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Background: In mechanically ventilated acute respiratory distress syndrome (ARDS) patients infected with the novel coronavirus disease (COVID-19), we frequently recognised the development of pneumomediastinum and/or subcutaneous emphysema despite employing a protective mechanical ventilation strategy. The purpose of this study was to determine if the incidence of pneumomediastinum/subcutaneous emphysema in COVID-19 patients was higher than in ARDS patients without COVID-19 and if this difference could be attributed to barotrauma or to lung frailty., Methods: We identified both a cohort of patients with ARDS and COVID-19 (CoV-ARDS), and a cohort of patients with ARDS from other causes (noCoV-ARDS).Patients with CoV-ARDS were admitted to an intensive care unit (ICU) during the COVID-19 pandemic and had microbiologically confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. NoCoV-ARDS was identified by an ARDS diagnosis in the 5 years before the COVID-19 pandemic period., Results: Pneumomediastinum/subcutaneous emphysema occurred in 23 out of 169 (13.6%) patients with CoV-ARDS and in three out of 163 (1.9%) patients with noCoV-ARDS (p<0.001). Mortality was 56.5% in CoV-ARDS patients with pneumomediastinum/subcutaneous emphysema and 50% in patients without pneumomediastinum (p=0.46).CoV-ARDS patients had a high incidence of pneumomediastinum/subcutaneous emphysema despite the use of low tidal volume (5.9±0.8 mL·kg -1 ideal body weight) and low airway pressure (plateau pressure 23±4 cmH 2 O)., Conclusions: We observed a seven-fold increase in pneumomediastinum/subcutaneous emphysema in CoV-ARDS. An increased lung frailty in CoV-ARDS could explain this finding more than barotrauma, which, according to its etymology, refers to high transpulmonary pressure., Competing Interests: Conflict of interest: D.H.L. Lemmers has nothing to disclose. Conflict of interest: M. Abu Hilal has nothing to disclose. Conflict of interest: C. Bnà has nothing to disclose. Conflict of interest: C. Prezioso has nothing to disclose. Conflict of interest: E. Cavallo has nothing to disclose. Conflict of interest: N. Nencini has nothing to disclose. Conflict of interest: S. Crisci has nothing to disclose. Conflict of interest: F. Fusina has nothing to disclose. Conflict of interest: G. Natalini has nothing to disclose., (Copyright ©ERS 2020.)

Background and Aim: failed back surgery syndrome is one of the most important causes of chronic low back pain that involve the physiology of autonomic nervous system factors. Some genetic and molecular factor can be determinant in the development of failed back surgery syndrome and novel therapy are needed. Pulsed radiofrequency treatment could be an innovative treatment option for this syndrome., Methods: 44 patients classified with failed back surgery syndrome from the Poliambulanza Foundation Hospital of Brescia patients were treated with standard therapy for six months; 9 of these patients who showed no improvement were candidates for pulsed radiofrequency therapy for three months., Results and Conclusions: reduction of lumbar and radicular pain, disability and number of drug classes prescribed improved significantly (p <0.001) in patients treated with pulsed radiofrequency compared to whom that follow only the standard therapy. The role of the nervous system is important for understanding how pulsed radiofrequency can improve the health of patients with back pain. We suggest that some genetic and molecular studies are needed for better understand the role of this therapy in back pain.

Background: Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection is associated with hypercoagulability caused by direct invasion of endothelial cells and\or proinflammatory cytokine release. Thromboprophylaxis with enoxaparin is recommended by current guidelines, but evidence is still weak. The aim of this study was to assess the impact of thromboprophylaxis with enoxaparin on hospital mortality in patients admitted for Coronavirus disease 2019 (COVID-19). The effects of enoxaparin on intensive care admission and hospital length-of-stay were evaluated as secondary outcomes., Methods: Observational cohort study, with data collected from patients admitted to Poliambulanza Foundation with positive real time reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2 from 20th February to 10th May 2020. Multivariate logistic regression with overlap weight propensity score was used to model hospital mortality and intensive care admission, hospital length-of-stay was analyzed with a multivariate Poisson regression. Seven hundred and ninety nine (57%) patients who received enoxaparin at least once during the hospitalization were included in the enoxaparin cohort, 604 (43%) patients who did not were included in the control cohort., Findings: At the adjusted analysis enoxaparin was associated with lower in-hospital mortality (Odds Ratio 0·53, 95% C.I. 0·40-0·70) compared with no enoxaparin treatment. Hospital length-of-stay was longer for patients treated with enoxaparin (Incidence Rate Ratios 1·45, 95% C.I. 1·36-1·54). Enoxaparin treatment was associated with reduced risk of intensive care admission at the adjusted analysis (Odds Ratio 0·48, 95% C.I. 0·32-0·69)., Interpretation: This study shows that treatment with enoxaparin during hospital stay is associated with a lower death rate and, while results from randomized clinical trials are still pending, this study supports the use of thromboprophylaxis with enoxaparin in all patients admitted for COVID-19. Moreover, when enoxaparin is used on the wards, it reduces the risk of Intensive Care Unit admission., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 The Author(s).)

The sacroiliac joints connect the base of the sacrum to the ilium. When inflamed, they are suspected to cause low back pain. Inflammation of the sacroiliac joints is called sacroiliitis. The severity of the pain varies and depends on the degree of inflammation. Sacroiliitis is a hallmark of seronegative spondyloarthropathies. The presence or absence of chronic sacroiliitis is an important clue in the diagnosis of low back pain. This article aims to provide a concise overview of the anatomy, physiology, and molecular biology of sacroiliitis to aid clinicians in the assessment and management of sacroiliitis. For this narrative review, we evaluated articles in English published before August 2019 in PubMed. Then, we selected articles related to the painful manifestations of the sacroiliac joint. From the retrieved articles, we found that chronic sacroiliitis may be caused by various forms of spondyloarthritis, such as ankylosing spondyloarthritis. Sacroiliitis can also be associated with inflammatory bowel disease, Crohn's disease, gout, tuberculosis, brucellosis, and osteoarthritis, indicating common underlying etiological factors. The pathophysiology of sacroiliitis is complex and may involve internal, environmental, immunological, and genetic factors. Finally, genetic factors may also play a central role in progression of the disease. Knowing the genetic pre-disposition for sacroiliitis can be useful for diagnosis and for formulating treatment regimens, and may lead to a substantial reduction in disease severity and duration and to improved patient performance.

Importance: Many patients with coronavirus disease 2019 (COVID-19) are critically ill and require care in the intensive care unit (ICU)., Objective: To evaluate the independent risk factors associated with mortality of patients with COVID-19 requiring treatment in ICUs in the Lombardy region of Italy., Design, Setting, and Participants: This retrospective, observational cohort study included 3988 consecutive critically ill patients with laboratory-confirmed COVID-19 referred for ICU admission to the coordinating center (Fondazione IRCCS [Istituto di Ricovero e Cura a Carattere Scientifico] Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy) of the COVID-19 Lombardy ICU Network from February 20 to April 22, 2020. Infection with severe acute respiratory syndrome coronavirus 2 was confirmed by real-time reverse transcriptase-polymerase chain reaction assay of nasopharyngeal swabs. Follow-up was completed on May 30, 2020., Exposures: Baseline characteristics, comorbidities, long-term medications, and ventilatory support at ICU admission., Main Outcomes and Measures: Time to death in days from ICU admission to hospital discharge. The independent risk factors associated with mortality were evaluated with a multivariable Cox proportional hazards regression., Results: Of the 3988 patients included in this cohort study, the median age was 63 (interquartile range [IQR] 56-69) years; 3188 (79.9%; 95% CI, 78.7%-81.1%) were men, and 1998 of 3300 (60.5%; 95% CI, 58.9%-62.2%) had at least 1 comorbidity. At ICU admission, 2929 patients (87.3%; 95% CI, 86.1%-88.4%) required invasive mechanical ventilation (IMV). The median follow-up was 44 (95% CI, 40-47; IQR, 11-69; range, 0-100) days; median time from symptoms onset to ICU admission was 10 (95% CI, 9-10; IQR, 6-14) days; median length of ICU stay was 12 (95% CI, 12-13; IQR, 6-21) days; and median length of IMV was 10 (95% CI, 10-11; IQR, 6-17) days. Cumulative observation time was 164 305 patient-days. Hospital and ICU mortality rates were 12 (95% CI, 11-12) and 27 (95% CI, 26-29) per 1000 patients-days, respectively. In the subgroup of the first 1715 patients, as of May 30, 2020, 865 (50.4%) had been discharged from the ICU, 836 (48.7%) had died in the ICU, and 14 (0.8%) were still in the ICU; overall, 915 patients (53.4%) died in the hospital. Independent risk factors associated with mortality included older age (hazard ratio [HR], 1.75; 95% CI, 1.60-1.92), male sex (HR, 1.57; 95% CI, 1.31-1.88), high fraction of inspired oxygen (Fio2) (HR, 1.14; 95% CI, 1.10-1.19), high positive end-expiratory pressure (HR, 1.04; 95% CI, 1.01-1.06) or low Pao2:Fio2 ratio (HR, 0.80; 95% CI, 0.74-0.87) on ICU admission, and history of chronic obstructive pulmonary disease (HR, 1.68; 95% CI, 1.28-2.19), hypercholesterolemia (HR, 1.25; 95% CI, 1.02-1.52), and type 2 diabetes (HR, 1.18; 95% CI, 1.01-1.39). No medication was independently associated with mortality (angiotensin-converting enzyme inhibitors HR, 1.17; 95% CI, 0.97-1.42; angiotensin receptor blockers HR, 1.05; 95% CI, 0.85-1.29)., Conclusions and Relevance: In this retrospective cohort study of critically ill patients admitted to ICUs in Lombardy, Italy, with laboratory-confirmed COVID-19, most patients required IMV. The mortality rate and absolute mortality were high.

Objective: To investigate patient characteristics and factors that increase the risk of being admitted to intensive care and that influence survival in cases of SARS-CoV-2 pneumonia., Patients and Methods: One-hundred and ninety-one SARS-CoV-2 patients were admitted to the "Fondazione Poliambulanza di Brescia" Hospital (Brescia, Lombardy, Italy) in the period 1st March 2020 to 11th April 2020. Data on demographics, clinical presentation at admission, co-morbidities, pharmacological treatment, admission to intensive care and death was recorded. Logistic regression and survival analysis were carried out to investigate the risk of being admitted to intensive care and the risk of death., Results: The mean age of the study cohort was 64.6±9.9 years (range 20-88). Median BMI was 28.5±5 kg/m2. Fever (81%) and dyspnea (65%) were the most common symptoms on admission. Most of patients (63%) had at least one co-existing disease. The 157 (82%) patients admitted to intensive care were more likely to be of intermediate age (60-69 years; OR 3.23, 95% CI 1.32-8.38), overweight (OR 2.66, 95% CI 1.02-7.07) or obese (OR 5.63, 95% CI 1.73-21.09) and with lymphocytopenia (OR 2.75, 95% CI 1.17-6.89) than the 34 patients admitted to the ordinary ward. During intensive care, 50% of patients died and their death was associated with older age (HR 2.06, 95% CI 1.07-3.97), obesity (HR 2.23, 95% CI 1.15-4.35) and male gender (HR 1.9, 95% CI 1.02-3.57)., Conclusions: We found that admission to intensive care and poor survival were associated with advanced age and higher body mass index, albeit with differences in statistical significance. Pre-existing diseases and symptoms on admission were not associated with different clinical outcomes. Interestingly, male gender was more prevalent among SARS-CoV-2 patients and was related negatively to survival, but it was not associated with more frequent admission to intensive care.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has led to widespread use of hydroxychloroquine and azithromycin despite the lack of conclusive evidence for their safety and efficacy. We evaluated the association between treatment with hydroxychloroquine and/or azithromycin and hospital mortality as the primary outcome. We compared the hospital mortality of patients treated with hydroxychloroquine alone, azithromycin alone, or their combination to the mortality of patients who received neither drug. A logistic multivariate model with overlap weight propensity score was used for estimation of odds ratios (ORs) with 95% confidence intervals (95% CIs). One thousand four hundred and three patients with SARS-CoV-2 infection were admitted to the hospital. At the time of the analysis, the outcome was available for 1376 (98%) of them. Five hundred and eighty-seven patients (42%) received azithromycin and 377 patients (27%) received hydroxychloroquine, alone or in combination. In-hospital mortality was 26%. After the adjusted analysis, azithromycin alone was associated with lower mortality (OR 0.60, 95% CI 0.42-0.85) compared to no treatment. Hydroxychloroquine alone (OR 0.76, 95% CI 0.53-1.08) and the combination of azithromycin and hydroxychloroquine (OR 1.13, 95% CI 0.77-1.69) were not associated with hospital mortality. In this cohort of patients, azithromycin alone was associated with lower hospital mortality but hydroxychloroquine was not associated with increased or reduced mortality. While we await randomized clinical trials, these data support the use of azithromycin in novel coronavirus disease 2019 (COVID-19) and can contribute to better understanding of its role in further meta-analyses.

Importance: In December 2019, a novel coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) emerged in China and has spread globally, creating a pandemic. Information about the clinical characteristics of infected patients who require intensive care is limited., Objective: To characterize patients with coronavirus disease 2019 (COVID-19) requiring treatment in an intensive care unit (ICU) in the Lombardy region of Italy., Design, Setting, and Participants: Retrospective case series of 1591 consecutive patients with laboratory-confirmed COVID-19 referred for ICU admission to the coordinator center (Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy) of the COVID-19 Lombardy ICU Network and treated at one of the ICUs of the 72 hospitals in this network between February 20 and March 18, 2020. Date of final follow-up was March 25, 2020., Exposures: SARS-CoV-2 infection confirmed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay of nasal and pharyngeal swabs., Main Outcomes and Measures: Demographic and clinical data were collected, including data on clinical management, respiratory failure, and patient mortality. Data were recorded by the coordinator center on an electronic worksheet during telephone calls by the staff of the COVID-19 Lombardy ICU Network., Results: Of the 1591 patients included in the study, the median (IQR) age was 63 (56-70) years and 1304 (82%) were male. Of the 1043 patients with available data, 709 (68%) had at least 1 comorbidity and 509 (49%) had hypertension. Among 1300 patients with available respiratory support data, 1287 (99% [95% CI, 98%-99%]) needed respiratory support, including 1150 (88% [95% CI, 87%-90%]) who received mechanical ventilation and 137 (11% [95% CI, 9%-12%]) who received noninvasive ventilation. The median positive end-expiratory pressure (PEEP) was 14 (IQR, 12-16) cm H2O, and Fio2 was greater than 50% in 89% of patients. The median Pao2/Fio2 was 160 (IQR, 114-220). The median PEEP level was not different between younger patients (n = 503 aged ≤63 years) and older patients (n = 514 aged ≥64 years) (14 [IQR, 12-15] vs 14 [IQR, 12-16] cm H2O, respectively; median difference, 0 [95% CI, 0-0]; P = .94). Median Fio2 was lower in younger patients: 60% (IQR, 50%-80%) vs 70% (IQR, 50%-80%) (median difference, -10% [95% CI, -14% to 6%]; P = .006), and median Pao2/Fio2 was higher in younger patients: 163.5 (IQR, 120-230) vs 156 (IQR, 110-205) (median difference, 7 [95% CI, -8 to 22]; P = .02). Patients with hypertension (n = 509) were older than those without hypertension (n = 526) (median [IQR] age, 66 years [60-72] vs 62 years [54-68]; P < .001) and had lower Pao2/Fio2 (median [IQR], 146 [105-214] vs 173 [120-222]; median difference, -27 [95% CI, -42 to -12]; P = .005). Among the 1581 patients with ICU disposition data available as of March 25, 2020, 920 patients (58% [95% CI, 56%-61%]) were still in the ICU, 256 (16% [95% CI, 14%-18%]) were discharged from the ICU, and 405 (26% [95% CI, 23%-28%]) had died in the ICU. Older patients (n = 786; age ≥64 years) had higher mortality than younger patients (n = 795; age ≤63 years) (36% vs 15%; difference, 21% [95% CI, 17%-26%]; P < .001)., Conclusions and Relevance: In this case series of critically ill patients with laboratory-confirmed COVID-19 admitted to ICUs in Lombardy, Italy, the majority were older men, a large proportion required mechanical ventilation and high levels of PEEP, and ICU mortality was 26%.

The purpose of this review is to summarize the pathophysiology of complex regional pain syndrome (CRPS), the underlying molecular mechanisms, and potential treatment options for its management. CRPS is a multifactorial pain condition. CRPS is characterized by prolonged or excessive pain and changes in skin color and temperature, and/or swelling in the affected area, and is generally caused by stimuli that lead to tissue damage. An inflammatory response involving various cytokines and autoantibodies is generated in response to acute trauma/stress. Chronic phase pathophysiology is more complex, involving the central and peripheral nervous systems. Various genetic factors involved in the chronicity of pain have been identified in CRPS patients. As with other diseases of complex pathology, CRPS is difficult to treat and no single treatment regimen is the same for two patients. Stimulation of the vagus nerve is a promising technique being tested for different gastrointestinal and inflammatory diseases. CRPS is more frequent in individuals of 61-70 years of age with a female to male ratio of 3 : 1. Menopause, migraine, osteoporosis, and asthma all represent risk factors for CRPS and in smokers the prognosis appears to be more severe. The pathophysiological mechanisms underlying CRPS involve both inflammatory and neurological pathways. Understanding the molecular basis of CRPS is important for its diagnosis, management, and treatment. For instance, vagal nerve stimulation might have the potential for treating CRPS through the cholinergic anti-inflammatory pathway., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this article., (Copyright © 2020 Manuela Baronio et al.)

Background: Viral infectivity depends on interactions between components of the host cell plasma membrane and the virus envelope. Here we review strategies that could help stem the advance of the SARS-COV-2 epidemic., Methods and Results: We focus on the role of lipid structures, such as lipid rafts and cholesterol, involved in the process, mediated by endocytosis, by which viruses attach to and infect cells. Previous studies have shown that many naturally derived substances, such as cyclodextrin and sterols, could reduce the infectivity of many types of viruses, including the coronavirus family, through interference with lipid-dependent attachment to human host cells., Conclusions: Certain molecules prove able to reduce the infectivity of some coronaviruses, possibly by inhibiting viral lipid-dependent attachment to host cells. More research into these molecules and methods would be worthwhile as it could provide insights the mechanism of transmission of SARS-COV-2 and, into how they could become a basis for new antiviral strategies.

Background: Post-traumatic cerebral infarction (PTCI) is common after traumatic brain injury (TBI). It is unclear what the occurrence of a PTCI is, how it impacts the long-term outcome, and whether it adds incremental prognostic value to established outcome predictors., Methods: This was a prospective multicenter cohort study of moderate and severe TBI patients. The primary objective was to evaluate if PTCI was an independent risk factor for the 6-month outcome assessed with the Glasgow Outcome Scale (GOS). We also assessed the PTCI occurrence and if it adds incremental value to the International Mission for Prognosis and Clinical Trial design in TBI (IMPACT) core and extended models., Results: We enrolled 143 patients, of whom 47 (32.9%) developed a PTCI. In the multiple ordered logistic regression, PTCI was retained in both the core and extended IMPACT models as an independent predictor of the GOS. The predictive performances increased significantly when PTCI was added to the IMPACT core model (AUC = 0.73, 95% C.I. 0.66-0.82; increased to AUC = 0.79, 95% CI 0.71-0.83, p = 0.0007) and extended model (AUC = 0.74, 95% C.I. 0.65-0.81 increased to AUC = 0.80, 95% C.I. 0.69-0.85; p = 0.00008). Patients with PTCI showed higher ICU mortality and 6-month mortality, whereas hospital mortality did not differ between the two groups., Conclusions: PTCI is a common complication in patients suffering from a moderate or severe TBI and is an independent risk factor for long-term disability. The addition of PTCI to the IMPACT core and extended predictive models significantly increased their performance in predicting the GOS., Trial Registration: The present study was registered in ClinicalTrial.gov with the ID number NCT02430324.

Background: In some patients with auto-positive end-expiratory pressure (auto-PEEP), application of PEEP lower than auto-PEEP maintains a constant total PEEP, therefore reducing the inspiratory threshold load without detrimental cardiovascular or respiratory effects. We refer to these patients as "complete PEEP-absorbers." Conversely, adverse effects of PEEP application could occur in patients with auto-PEEP when the total PEEP rises as a consequence. From a pathophysiological perspective, all subjects with flow limitation are expected to be "complete PEEP-absorbers," whereas PEEP should increase total PEEP in all other patients. This study aimed to empirically assess the extent to which flow limitation alone explains a "complete PEEP-absorber" behavior (i.e., absence of further hyperinflation with PEEP), and to identify other factors associated with it., Methods: One hundred patients with auto-PEEP of at least 5 cmH2O at zero end-expiratory pressure (ZEEP) during controlled mechanical ventilation were enrolled. Total PEEP (i.e., end-expiratory plateau pressure) was measured both at ZEEP and after applied PEEP equal to 80 % of auto-PEEP measured at ZEEP. All measurements were repeated three times, and the average value was used for analysis., Results: Forty-seven percent of the patients suffered from chronic pulmonary disease and 52 % from acute pulmonary disease; 61 % showed flow limitation at ZEEP, assessed by manual compression of the abdomen. The mean total PEEP was 7 ± 2 cmH2O at ZEEP and 9 ± 2 cmH2O after the application of PEEP (p < 0.001). Thirty-three percent of the patients were "complete PEEP-absorbers." Multiple logistic regression was used to predict the behavior of "complete PEEP-absorber." The best model included a respiratory rate lower than 20 breaths/min and the presence of flow limitation. The predictive ability of the model was excellent, with an overoptimism-corrected area under the receiver operating characteristics curve of 0.89 (95 % CI 0.80-0.97)., Conclusions: Expiratory flow limitation was associated with both high and complete "PEEP-absorber" behavior, but setting a relatively high respiratory rate on the ventilator can prevent from observing complete "PEEP-absorption." Therefore, the effect of PEEP application in patients with auto-PEEP can be accurately predicted at the bedside by measuring the respiratory rate and observing the flow-volume loop during manual compression of the abdomen.

Objective: The history of left ventricular reconstruction has demonstrated that the full spectrum of recoverable physiologic parameters is essential for a good functional result. We report the long-term outcome of a new surgical technique that arranges myocardial fibers in a near-normal disposition, also recovering left ventricular twisting., Methods: Between May 2006 and October 2013, 29 consecutive patients with previous anterior myocardial infarction and heart failure symptoms underwent physiologic left ventricular reconstruction surgery and coronary revascularization. Patients were examined by means of standard echocardiography and 2-dimensional speckle tracking at 8 time steps until 7 years after surgery. Ten geometric and functional parameters were evaluated at each step and analyzed by the linear mixed model test., Results: Hospital mortality was 0%. The mean percentage of indexed end-diastolic and end-systolic volume reduction was 45.7% and 50.9%, respectively. Ejection fraction and all of the volumes were significantly different in the postoperative period with a steady correction during time. Diastolic parameters were not worsened by surgical reconstruction. Ejection fraction and deceleration time showed a significant improvement during time. Left ventricular torsion increased immediately after the surgical correction from 2.8 ± 4.4 degrees to 8.7 ± 3.9 degrees (P = .02) and was still present 4 years after surgery., Conclusions: Surgical conduction of ventricular reconstruction should be standardized to achieve the full spectrum of recoverable physiologic parameters. The renewal of ventricular torsion should be pursued as an adjunctive element of ventricular efficiency, mainly in ventricles that work at a critical level in the Frank-Starling relationship and pressure-volume loop., (Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Previous physiological studies have identified factors that are involved in auto-PEEP generation. In our study, we examined how much auto-PEEP is generated from factors that are involved in its development., Methods: One hundred eighty-six subjects undergoing controlled mechanical ventilation with persistent expiratory flow at the beginning of each inspiration were enrolled in the study. Volume-controlled continuous mandatory ventilation with PEEP of 0 cm H2O was applied while maintaining the ventilator setting as chosen by the attending physician. End-expiratory and end-inspiratory airway occlusion maneuvers were performed to calculate respiratory mechanics, and tidal flow limitation was assessed by a maneuver of manual compression of the abdomen., Results: The variable with the strongest effect on auto-PEEP was flow limitation, which was associated with an increase of 2.4 cm H2O in auto-PEEP values. Moreover, auto-PEEP values were directly related to resistance of the respiratory system and body mass index and inversely related to expiratory time/time constant. Variables that were associated with the breathing pattern (tidal volume, frequency minute ventilation, and expiratory time) did not show any relationship with auto-PEEP values. The risk of auto-PEEP ≥5 cm H2O was increased by flow limitation (adjusted odds ratio 17; 95% CI: 6-56.2), expiratory time/time constant ratio <1.85 (12.6; 4.7-39.6), respiratory system resistance >15 cm H2O/L s (3; 1.3-6.9), age >65 y (2.8; 1.2-6.5), and body mass index >26 kg/m(2) (2.6; 1.1-6.1)., Conclusions: Flow limitation, expiratory time/time constant, resistance of the respiratory system, and obesity are the most important variables that affect auto-PEEP values. Frequency expiratory time, tidal volume, and minute ventilation were not independently associated with auto-PEEP. Therapeutic strategies aimed at reducing auto-PEEP and its adverse effects should be primarily oriented to the variables that mainly affect auto-PEEP values., (Copyright © 2016 by Daedalus Enterprises.)

Background: Evidence on pain management highlights the importance of a multidisciplinary approach in order to achieve optimal therapeutic results. Such programs can be guaranteed by the Centers for Pain Management (CPMs), in which multidisciplinary teams are able to provide advanced and specialized activities for the assessment, diagnosis and treatment of chronic benign pain. To date, information related to healthcare supply and the organizational structure of these centers in Italy is incomplete. The aim of this paper was to provide an overview of the healthcare network of the CPMs in the Lazio region., Methods: A descriptive survey was conducted in all the 37 CPMs existing in the Lazio region in 2011 of which 28 participated., Results: CPMs were located either in Universities or in public or private hospital facilities. They included a clinic, a Day Hospital service, Day surgery and day-beds. CPMs were managed by anaesthesiologists who, in most instances, did not work in a multidisciplinary team. The number of other health professionals available, such as nurses, psychologists and physiotherapists, was limited. CPMs mainly provided drug therapy, Complementary Alternative Medicine (CAM) and complex interventional treatments. The median waiting time was 30 days. The clinics were not homogeneously distributed in the region with a higher concentration in Rome (56%), followed by other provinces of the Lazio region (26%) and the province of Rome (18%). Clearly, Rome was the city which offered the greatest range of healthcare services and the highest number of consultations with patients, which significantly differed from those of the other areas (χ²=19.6 p<0.01)., Conclusions: In 2011, the availability of CPMs was not equally distributed throughout the territory, and there was an over-utilization of the facilities in Rome and an under-utilization in the provincial areas. Moreover, this study showed a lack of a multi-professional approach to chronic pain management.

Introduction: The beneficial effect of low tidal volume (TV) ventilation strategy on mortality in patients with acute respiratory distress syndrome (ARDS) has been attributed to the protective effect on ventilator-induced lung injury, and yet its effect on cardiovascular function might also play an important role. The aim of this study was to assess whether low TV ventilation improves cardiac output and oxygen delivery compared with high TV ventilation strategy in patients with ARDS., Methods: In this crossover randomized clinical trial 16 ARDS patients were recruited in an intensive care unit at a university-affiliated hospital. Each patient was ventilated for 30 min with low (6 mL/kg) and 30 min with high (12 mL/kg) TV. The two experimental periods, applied in random order and with allocation concealment, were separated by 30 min of basal ventilation. Minute ventilation was constantly maintained by appropriate respiratory rate changes., Results: Compared with high TV ventilation, low TV ventilation showed decreased pH (7.37 vs. 7.41, P = 0.001) and increased PaCO₂ (49 vs. 43 mmHg; P = 0.002). Cardiac index and oxygen delivery index were increased with low compared with high TV ventilation (3.9 vs. 3.5 L.min⁻¹.m⁻², P = 0.012, and 521 vs. 463 mL.min⁻¹.m⁻², P = 0.002, respectively), while oxygen extraction ratio decreased (0.36 vs. 0.44, P = 0.027). In four patients oxygen extraction ratio was >0.5 during high TV but not during low TV strategy. The magnitude of the change in cardiac index was positively associated with PaCO₂ variation (P = 0.004), while it was unrelated to the magnitude of changes in TV and airway pressure. The decrease of cardiac index was predicted by PaCO₂ reduction, with and area under ROC curve of 0.72., Conclusions: Our findings suggest that a low TV ventilation strategy increases cardiac index and oxygen delivery, thus supporting the hypothesis that the beneficial effect of low TV ventilation in patients with ARDS could be partially explained by hemodynamic improvement. In other words, low tidal volume ventilation could be protective also for the cardiovascular system and not only for the lung. The slight increase of PaCO₂ during low TV ventilation seems to predict the increase of cardiac index., Trial Registration: ClinicalTrials.gov: NCT00713713.

We report on two sisters, 17 and 12 years of age, with clinical features suggesting narcolepsy with cataplexy (NC): daytime sleepiness, spontaneous and emotionally triggered sudden falls to the ground, and overweight/obesity. MSLT showed borderline sleep latency, with 1 and 0 sleep onset REM periods. HLA typing disclosed the DQB1*0602 allele. Video-polygraphy of the spells ruled out NC diagnosis by demonstrating their easy elicitation by suggestion, with wake EEG, electromyographic persistence of muscle tone, and stable presence of tendon reflexes (i.e., pseudo-cataplexy), together with normal cerebrospinal hypocretin-1 levels. Our cases emphasize the need of a clear depiction of cataplexy pattern at the different ages, the usefulness of examining ictal neurophysiology, and collecting all available disease markers in ambiguous cases.

Background: The purpose of this study was to evaluate early and midterm results of tibial bypasses comparing precuffed expanded polytetrafluoroethylene (PTFE) graft (Distaflo) and heparin-bonded PTFE graft (Propaten) with a distal vein patch., Methods: This is a retrospective cohort analysis evaluating patients who underwent PTFE femorocrural bypasses between April 2004 and December 2010 at the Vascular Surgery Division of the Poliambulanza Foundation Hospital (Brescia, Italy). Results were analyzed in terms of primary and secondary graft patency, limb salvage, and survival with univariate (Kaplan-Meier curves and log-rank test) and multivariate (Cox regression) analyses., Results: After analyzing many patients, we found 79 femorotibial bypass PTFE grafts. We used a Propaten graft and vein patch in 40 patients and a Distaflo graft in 39 patients. The two groups were comparable for main risk factors, except for age. Indication for surgical revascularization was critical limb ischemia in all patients. In 54 cases (68%), it was a redo bypass because of a previously failed revascularization. Perioperative mortality within 30 days from intervention was 2.5%, whereas overall mortality during follow-up was 29%, with a 36-month survival rate of 58% (95% confidence interval [CI]: 0.44-0.77) on life table analysis. We observed a significant difference between two groups in terms of survival at 36 months (Propaten: 0.84 [95% CI: 0.69-1]; Distaflo: 0.21 [95% CI: 0.07-0.63]; P < 0.001; 95% CI: 0.07-0.63; odds ratio [OR]: 0.21). At 24 months, the two groups (Propaten vs. Distaflo) were equivalent in terms of primary patency (Propaten: 0.33 [95% CI: 0.21-0.53]; Distaflo: 0.47 [95% CI: 0.32-0.70]; P = 0.793), secondary patency (Propaten: 0.36 [95% CI: 0.23-0.57]; Distaflo: 0.49 [95% CI: 0.33-0.72]; P = 0.855), and limb salvage (Propaten: 0.65 [95% CI: 0.51-0.84]; Distaflo: 0.57 [95% CI: 0.41-0.79]; P = 0.18). At Cox regression analysis, age of >80 years (P < 0.04; 95% CI: 0.23-0.95; OR: 0.47), peroneal artery distal anastomosis (P < 0.04; 95% CI: 1.04-5.62; OR: 2.42), simultaneous adjunctive procedures (P < 0.02; 95% CI: 1.21-17.74; OR: 4.64), and redo bypass (P < 0.05; 95% CI: 1-6.26; OR: 2.5) were associated with long-term poorer primary patency rates. Postoperative treatment with warfarin therapy compared with antiplatelet therapy was independently associated with better secondary patency (P < 0.04; 95% CI: 0.20-0.95; OR: 0.44) and limb salvage (P < 0.03; 95% CI: 0.11-0.87; OR: 0.32) rates., Conclusions: Distaflo and Propaten with a distal vein patch in our experience have similar patency and limb salvage results, although further randomized and larger studies are necessary. Postoperative anticoagulation therapy seems better than antiplatelet therapy in terms of patency and limb salvage rate., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Mean arterial pressure above 65 mmHg is recommended for critically ill hypotensive patients whereas they do not benefit from supranormal cardiac output values. In this study we investigated if the increase of mean arterial pressure after volume expansion could be predicted by cardiovascular and renal variables. This is a relevant topic because unnecessary positive fluid balance increases mortality, organ dysfunction and Intensive Care Unit length of stay., Methods: Thirty-six hypotensive patients (mean arterial pressure < 65 mmH) received a fluid challenge with hydroxyethyl starch. Patients were excluded if they had active bleeding and/or required changes in vasoactive agents infusion rate in the previous 30 minutes. Responders were defined by the increase of mean arterial pressure value to over 65 mmHg or by more than 20% with respect to the value recorded before fluid challenge. Measurements were performed before and at one hour after the end of fluid challenge., Results: Twenty-two patients (61%) increased arterial pressure after volume expansion. Baseline heart rate, arterial pressure, central venous pressure, central venous saturation, central venous to arterial PCO2 difference, lactate, urinary output, fractional excretion of sodium and urinary sodium/potassium ratio were similar between responder and non-responder. Only 7 out of 36 patients had valuable dynamic indices and then we excluded them from analysis. When the variables were tested as predictors of responders, they showed values of areas under the ROC curve ranging between 0.502 and 0.604. Logistic regression did not reveal any association between variables and responder definition., Conclusions: Fluid challenge did not improve arterial pressure in about one third of hypotensive critically ill patients. Cardiovascular and renal variables did not enable us to predict the individual response to volume administration., Trial Registration: ClinicalTrials.gov: NCT00721604.

We have previously reported that treatment of colorectal cancer cells with mesalazine results in the up-regulated expression of a novel member of the cadherin protein superfamily, named μ-protocadherin, which is able to sequester β-catenin on plasmatic membrane of treated cells inhibiting its proliferation signalling pathway. This finding suggests that μ-protocadherin could exert an oncosuppressive effect on colorectal epithelium. The purpose of our study was to assess whether μ-protocadherin expression is down-regulated during colorectal carcinogenesis. This issue was addressed by analyzing the messenger RNA and protein expression of μ-protocadherin in normal and tumor colorectal cell samples using a combination of quantitative real-time polymerase chain reaction, microarray analysis, and immunohistochemical examination. To better contextualize the role played by μ-protocadherin in the pathogenesis of colorectal cancer, this last assay was also extended to β-catenin, E-cadherin, and Ki-67 proteins. The results obtained evidenced that (1) levels of μ-protocadherin transcript were down-regulated in all the analyzed colorectal cancer samples as compared with normal mucosa; (2) expression of μ-protocadherin protein was completely lost in most analyzed colorectal cancer samples (71%); (3) μ-protocadherin retains β-catenin on the plasmatic membrane of normal colon enterocytes, which implies that β-catenin is released from this site and translocated to the nucleus in colorectal cancer cells. Our data consequently suggest that down-regulation of μ-protocadherin expression is a common event in colorectal carcinogenesis and might therefore play an important role in this pathologic process., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Properly titrated opiates decrease respiratory rate but do not affect tidal volume or induce respiratory acidosis., Objective: To determine whether remifentanil improves breathing pattern or reduces inspiratory effort in patients with acute respiratory failure and tachypnea or rapid shallow breathing., Methods: We studied 14 patients who developed tachypnea and/or rapid shallow breathing if the pressure support level was reduced. During pressure support ventilation, each patient received 30-min infusions, separated by 30 min, of remifentanil and placebo. Measurements were obtained before commencing and before stopping each infusion, and after 3 min of unassisted breathing. The main outcomes were rapid shallow breathing index and change in pressure-time product., Results: Remifentanil did not significantly affect tidal volume. During pressure support ventilation, remifentanil infusion reduced respiratory rate, pressure-time product, and cardiovascular double product (heart rate × systolic arterial pressure) without modifying the sedation score. Mean P(aCO(2)) showed a small and clinically negligible increase during remifentanil, but P(aCO(2)) increased more in the hypercapnic patients than in the normocapnic patients. Remifentanil reduced the rapid shallow breathing index after 3 min of unassisted breathing., Conclusions: Remifentanil improved respiratory pattern and decreased inspiratory muscles effort in patients with tachypnea or rapid shallow breathing, but did not affect oxygenation or sedation. Though the acid-base balance did not show clinically relevant changes on average, we cannot exclude the possibility that remifentanil might prolong weaning in hypercapnic patients. (Clinical-Trials.gov registration NCT00665119.)

We compared the risk of pulmonary aspiration in patients whose lungs were mechanically ventilated through a laryngeal mask airway (35 630 procedures) or tracheal tube (30 082 procedures). Three cases of pulmonary aspiration occurred with the laryngeal mask airway and seven with the tracheal tube. There were no deaths related to pulmonary aspiration. The incidence and outcome of pulmonary aspiration detected in this study were similar to those previously reported. The adjusted odds ratio (OR) for pulmonary aspiration with the laryngeal mask airway was 1.06 (95% CI 0.20-5.62). Unplanned surgery (OR 30.5, 95% CI 8.6-108.9) and male sex (OR 8.6, 95% CI 1.1-68) were associated with an increased risk of aspiration and age < 14 years with a reduced risk (OR 0.21, 95% CI 0.07-0.64). There were contraindications and exclusions to the use of the laryngeal mask airway but in this selected population the use of an laryngeal mask airway was not associated with an increased risk of pulmonary aspiration compared with a tracheal tube.

We report 2 outbreaks of Opisthorchis felineus infection caused by the consumption of tench filets (Tinca tinca) from a lake in Italy. Of the 22 infected persons, 10 (45.4%) were asymptomatic. When present, symptoms (fever, nausea, abdominal pain, and myalgias) were mild. Eosinophilia occurred in all infected persons.

Purpose: Resection line infiltration (RLI) after surgical treatment represents an unfavorable prognostic factor in advanced gastric cancer. We performed a retrospective analysis of 89 patients with resection line involvement who did not undergo reoperation., Methods: On behalf of the Italian Research Group for Gastric Cancer, we present the characteristics and outcome of 89 patients who were submitted to surgical resection for gastric cancer from 1988 to 2001 and did not undergo reoperation because of disease extension or associated pathologies., Results: RLI was significantly higher in patients with T4 tumors and diffuse histological type. Anastomotic leakages were observed in 4.8% of infiltrated esophageal resection margins, whereas 1.9% of infiltrated duodenal resection lines showed duodenal fistulas. Five-year overall survival of patients with RLI was 29%. Prognosis was not affected by RLI in early forms (100% 5-year survival); however, 5-year survival in T2 and T3 stages was significantly lower with respect to the same stages without residual tumor. The influence of RLI on prognosis was confirmed in N0 as well as in N1 and N2 patients. RLI also was an independent prognostic at multivariate analysis (odds ratio = 1.5; 95% confidence interval, 1.08-2.08; P = 0.0144)., Conclusions: RLI significantly affects long-term survival of advanced gastric cancer. The impact on prognosis is independent of lymph node involvement. Patients in good general condition for whom radical surgery is possible should be considered for reoperation.

Background: Complete surgical resection of gastric cancer is potentially curative, but long-term survival is poor., Methods: Patients with histologically proven adenocarcinoma of the stomach of stages IB, II, IIIA and B, or IV (T4N2M0) and treated with potentially curative surgery were randomly assigned to follow-up alone or to intravenous treatment with four cycles (repeated every 21 days) of PELF (cisplatin [40 mg/m(2), on days 1 and 5], epirubicin [30 mg/m(2), days 1 and 5], L-leucovorin [100 mg/m(2), days 1-4], and 5-fluorouracil [300 mg/m(2), days 1-4] in a hospital setting. Frequencies and severity of adverse events were determined. Overall survival (OS) and disease-free survival (DFS) were compared between the treatment arms using Kaplan-Meier analysis and a Cox proportional hazards regression model. All statistical tests were two-sided., Results: From January 1995 through September 2000, 258 patients were randomly assigned to chemotherapy (n = 130) or surgery alone (n = 128). Patient characteristics were well balanced between the two arms. Among those who received chemotherapy, grade 3 or 4 toxic effects including vomiting, mucositis, and diarrhea were experienced by 21.1%, 8.4%, and 11.8% of patients, respectively. Leucopenia, anemia, and thrombocytopenia of grade 3 or 4 were experienced by 20.3%, 3.3%, and 4.2% of patients, respectively. After a median follow-up of 72.8 months, 128 patients (49.6%) experienced recurrence and 139 (53.9%) deaths were observed, one toxicity-related. Relative to treatment with surgery alone, adjuvant chemotherapy did not increase disease-free survival (hazard ratio [HR] of recurrence = 0.92; 95% confidence interval [CI] = 0.66 to 1.27) or overall survival (HR of death = 0.90; 95% CI = 0.64 to 1.26)., Conclusions: Our results failed to provide proof of an effect of adjuvant chemotherapy with PELF on overall survival or disease-free survival. The estimated effect of chemotherapy (10% reduction in the hazard of death or relapse) is modest and consistent with the results of meta-analyses of adjuvant chemotherapy without platinum agents.

Aims: The proportion between metastatic and examined lymph nodes (N-ratio) has been proposed as an independent prognostic factor in patients with gastric cancer. In the present work we validated the reliability of N-ratio in a large, multicenter series., Patients and Methods: We retrospectively reviewed the data of 1853 patients who underwent radical resection for gastric carcinoma. Survival of patients with >15 (Group-1, n=1421) and those with < or =15 (Group-2, n=432) lymph nodes examined was separately analyzed in order to evaluate the influence of lymph node dissection on disease staging. N-ratio categories (N-ratio 0, 0%; N-ratio 1, 1-9%; N-ratio 2, 10-25%; N-ratio 3, >25%) were determined by the best cut-off approach., Results: At multivariate analysis, N-ratio (but not TNM N-category) was retained as an independent prognostic factor both in Group-1 and Group-2 (HR for N-ratio 1, N-ratio 2 and N-ratio 3=1.67, 2.96 and 6.59, and 1.56, 2.68 and 4.28, respectively). After a median follow-up of 45.5 months, the 5-year overall survival rates of TNM N0, N1 and N2 patients were significantly different in Group-1 vs Group-2. This was not the case when adopting the N-ratio classification, suggesting that a low number of excised lymph nodes can lead to patients being understaged using the N-category, but not N-ratio. Moreover, N-ratio identified subsets of patients with significantly different survival rates within TNM N1 and N2 categories in both groups., Conclusions: N-ratio is a simple and reproducible prognostic tool that can stratify patients with gastric cancer, including those cases with limited lymph node dissection. These data support the rationale to propose the implementation of N-ratio into the current TNM staging system.

Purpose: To assess the frequency and magnitude of changes in lower rectal cancer resulting from preoperative therapy and its impact on sphincter-saving surgery. Preoperative therapy can increase the rate of preserving surgery by shrinking the tumor and enhancing its distance from the anal sphincter. However, reliable data concerning these modifications are not yet available in published reports., Methods and Materials: A total of 98 cases of locally advanced cancer of the lower rectum (90 Stage uT3-T4N0-N+ and 8 uT2N+M0) that had undergone preoperative therapy were studied by endorectal ultrasonography. The maximal size of the tumor and its distance from the anal sphincter were measured in millimeters before and after preoperative therapy. Surgery was performed 6-8 weeks after therapy, and the histopathologic margins were compared with the endorectal ultrasound data., Results: Of the 90 cases, 82.5% showed tumor downsizing, varying from one-third to two-thirds or more of the original tumor mass. The distance between the tumor and the anal sphincter increased in 60.2% of cases. The median increase was 0.73 cm (range, 0.2-2.5). Downsizing was not always associated with an increase in distance. Preserving surgery was performed in 60.6% of cases. It was possible in nearly 30% of patients in whom the cancer had reached the anal sphincter before the preoperative therapy. The distal margin was tumor free in these cases., Conclusion: The results of our study have shown that in very low rectal cancer, preoperative therapy causes tumor downsizing in >80% of cases and in more than one-half enhances the distance between the tumor and anal sphincter. These modifications affect the primary surgical options, facilitating or making sphincter-saving surgery possible.

Purpose: To investigate whether the ratio between metastatic and examined lymph nodes (N ratio) is a better prognostic factor as compared with traditional staging systems in patients with gastric cancer regardless of the extension of lymph node dissection., Patients & Methods: We retrospectively reviewed the data of 1853 patients who underwent radical resection for gastric carcinoma at 6 Italian centers. Patients with >15 (group 1, n = 1421) and those with 25%) were determined by the best cut-off approach., Results: After a median follow-up of 45.5 months (range, 4-182 months), the 5-year overall survival of N0, N1, and N2 patients of group 1 versus group 2 was 83.4% versus 74.2% (P = 0.0026), 54.3% versus 44.3% (P = 0.018), and 32.7% versus 14.7% (P = 0.004), respectively, suggesting that a low number of excised lymph nodes can lead to the understaging of patients. N ratio identified subsets of patients with significantly different survival rates within N1 and N2 stages in both groups. At multivariate analysis, the N ratio (but not N stage) was retained as an independent prognostic factor both in group 1 and group 2 (HR for N ratio 1, N ratio 2, and N ratio 3 = 1.67, 2.96, and 6.59, and 1.56, 2.68, and 4.28, respectively). In our series, the implementation of N ratio led to the identification of subgroups of patients prognostically more homogeneous than those classified by the TNM system., Conclusion: N ratio is a simple and reproducible prognostic tool that can stratify patients with gastric cancer also in case of limited lymph node dissection. These data may represent the rational for improving the prognostic power of current UICC TNM staging system and ultimately the selection of patients who may most benefit from adjuvant treatments.

In the present study, we compared indices of respiratory-induced variation obtained from direct arterial blood pressure measurement with analogous indices obtained from the plethysmogram measured by the pulse oximeter to assess the value of these indices for predicting the cardiac output increase in response to a fluid challenge. Thirty-two fluid challenges were performed in 22 hypotensive patients who were also monitored with a pulmonary artery catheter. Hemodynamic and plethysmographic data were collected before and after intravascular volume expansion. Patients were classified as nonresponders if their cardiac index did not increase by 15% from baseline. Nonresponding patients had both lower arterial pulse variation ([10 +/- 4]% vs [19 +/- 13]%, P = 0.020) and lower plethysmographic pulse variation ([12 +/- 7]% vs [21 +/- 14]%, P = 0.034) when compared with responders. Fluid responsiveness was similarly predicted by arterial and plethysmographic pulse variations (area under ROC curve 0.74 vs 0.72, respectively, P = 0.90) and by arterial and plethysmographic systolic variation (area under ROC curve 0.64 vs 0.72, respectively, P = 0.50). Nonresponders were identified by changes in pulse variation both on arterial and plethysmographic waveform (area under ROC curve 0.80 vs 0.87, respectively, P = 0.40) and by changes in arterial and plethysmographic systolic variations (area under ROC curve 0.84 vs 0.80, respectively, P = 0.76). In the population studied, plethysmographic dynamic indices of respiratory-induced variation were just as useful for predicting fluid responsiveness as the analogous indices derived from direct arterial blood pressure measurement. These plethysmographic indices could provide a noninvasive tool for predicting the cardiac output increase by administering fluid.

We analyzed ventilation-induced changes in arterial blood pressure and photoplethysmography from waveforms obtained by monitoring 57 patients in the operating room and intensive care unit. Analysis of systolic and pulse pressure variations during positive pressure ventilation, DeltaUp, DeltaDown, and changes in the preejection period on both arterial and photoplethysmographic waveforms were possible in 49 (86%) patients. The pulse pressure variation and preejection period were similar when calculated using both arterial blood pressure and photoplethysmography, whereas the other variables were different. Photoplethysmographic pulse variation >9% identified patients with arterial pulse pressure variation >13% (area under ROC curve = 0.85) or DeltaDown >5 mm Hg (area under ROC curve = 0.85). In hypotensive patients, photoplethysmographic pulse variation >9% remained the best threshold value (pulse pressure variation >13%: area under ROC curve = 0.90; DeltaDown >5 mm Hg: area under ROC curve = 0.93) for predicting fluid responsiveness. In conclusion, this study showed that pulse variations observed in the arterial pressure waveform and photoplethysmogram are similiar in response to positive pressure ventilation. Furthermore, photoplethysmographic pulse variation > 9% identifies patients with ventilation-induced arterial blood pressure variation that is likely to respond to fluid administration.

Aims and Background: The availability of new drugs offers the opportunity to improve the outcome of locally advanced rectal cancer. Raltitrexed and oxaliplatin are effective in advanced colorectal cancer with acceptable toxicity and can act as radiation enhancers as shown in phase I-II studies. The aim of the study was thus to determine the recommended dose of oxaliplatin concomitantly administered with raltitrexed and concurrent preoperative radiotherapy in patients with stage II-III extraperitoneal rectal cancer., Methods: From September 2001 to September 2002, 18 consecutive patients with T3/T4 rectal cancer were treated at our Institution with preoperative chemoradiation followed by surgery after 6-8 weeks. Pelvic radiotherapy was delivered at a dose of 45 Gy in 25 fractions in 5 weeks followed by a 5.4 Gy boost at 1.8 Gy daily. Concomitant chemotherapy consisted of 3 mg/m2/i.v. of raltitrexed on days 1, 19, 38 of radiotherapy treatment with incremental doses of oxaliplatin according to dose finding rules (4 dose levels: 65, 85, 110, 130 mg/m2). Dose-limiting toxicity for oxaliplatin was defined as either grade 3-4 hematological or grade 3-4 gastrointestinal or neurological toxicity. We studied a minimum of 3 patients at each dose level., Results: Three patients were treated at 65, 85, and 110 mg/m2/i.v., respectively, while 9 patients were recruited at the last dose level. Neither grade 3-4 gastrointestinal nor neurological toxicity were documented. Dose-limiting toxicity was documented in 2/9 subjects at the 130 mg/m2 level consisting of grade 3 transient asymptomatic leukopenia. Thirteen patients developed transient increase of one or more liver enzymes (grade 3-4) and 2 patients developed grade 3 perineal dermatitis. All patients received the programmed dose of radiotherapy. The chemotherapy regimen was not completed in 4 cases due to grade 2 protracted leukopenia., Conclusions: The maximum tolerated dose of oxaliplatin was not reached at the maximum dose level (i.v.); 130 mg/m2 can therefore be defined as the recommended dose. The combination of oxaliplatin with raltitrexed and radiotherapy can be considered feasible and well tolerated.

Background: Resection line involvement has been indicated as an important prognostic factor for gastric cancer. Its late detection renders the choice of treatment difficult for surgeons., Materials and Methods: We describe the multicenter experience of a group of 11 patients with early gastric carcinoma (EGC) and positive resection confirmed at histological examination who did not undergo surgical retreatment for reasons of associated disease, surgical considerations on duodenal stump, or patient refusal., Results: The gastric margin was involved in 4 patients, and 7 patients had duodenal resection line involvement. No surgical complications or postoperative deaths were observed. Five and 8-year survival was 100% and 86%, respectively. The only patient who relapsed did not have lymph node involvement and died from liver metastases, without local recurrence., Conclusions: It is sometimes difficult to accurately define the resection line in gastric cancer surgery, especially in the early stages of disease, but because of the strongly negative prognostic value of an infiltrated margin, frozen sections are recommended if neoplastic invasion is suspected and a new resection is always recommended if possible. Nevertheless, the good prognosis of resected EGC patients with resection line involvement must be considered before submitting patients with associated diseases to radical surgical retreatment.

Aims and Background: Adjuvant 5-FU chemotherapy plus radiotherapy represents the standard treatment for radically resected rectal cancer at high risk of relapse according to the NIH Consensus Conference. The therapeutic gain was obtained with a high rate of severe treatment-related toxicity and a suboptimal patient compliance with this regimen. Raltitrexed is a specific thymidylate synthase inhibitor with a convenient administration schedule, acceptable toxicity and radiosensitizing properties, as the published phase I trials in combination with radiotherapy have shown. The aim of this prospective multicenter phase II study was to evaluate the feasibility, gastrointestinal and hematological acute toxicity of raltitrexed in combination with radiotherapy in rectal cancer patients., Methods: From September 2000 to June 2004, 50 patients with radically resected stage II-III rectal adenocarcinoma were treated. All patients were evaluable for compliance and acute toxicity. Within 45-60 days of surgery, each patient underwent concomitant adjuvant radiochemotherapy. Radiotherapy was administered to the pelvis (plus perineum after abdominoperineal resection) with photon beam energy exceeding 5 MV, 3-4 fields, 45 Gy/25 fractions/5 weeks plus a boost delivered to the site of resected disease with 3-4 fields, 9 Gy/5 fractions/1 week to a total dose of 54 Gy. The boost dose was administered after complete exclusion of the small bowel from the treatment volumes; if this was not possible a total dose of 50.4 Gy was given. Raltitrexed was administered intravenously at a dose of 3 mg/m2 as a bolus injection on days 1 and 22 of radiotherapy one hour before treatment, for a total of two cycles. Each patient underwent weekly clinical evaluation and laboratory tests. Toxicity was assessed by the WHO scale., Results: Forty-five (90%) patients completed the established treatment. Acute severe toxicity included grade III proctitis in 4/50 (8%), grade III-IV diarrhea in 4/50 (8%), grade III perineal dermatitis in 4/50 (8%) and grade III leukopenia in 2/50 (4%) patients; five patients (10%) experienced a transient grade Ill increase in their liver biochemistry values., Conclusions: Our data related to acute toxicity and patient compliance proved the feasibility of this adjuvant radiochemotherapy treatment. A longer follow-up is necessary to evaluate the effectiveness of this new regimen in terms of disease-free and overall survival.

Purpose: In advanced rectal cancer, chemoradiation can induce downstaging until complete disappearance of the tumor or its persistence in minimal form. The complete sterilized and the minimal residual disease often are considered similar. We evaluated the specific incidence of these two conditions and analyzed their impact in terms of local recurrence, distant metastasis, and survival., Methods: We studied 139 uT3/T4 N0/N+ rectal cancers, treated with preoperative chemoradiation and curative surgery after six to eight weeks. We evaluated ypTNM stage and tumoral regression, according to the five degrees proposed by Dworak, with special attention to 4 and 3 (sterilized and minimal residual disease)., Results: Tumor downstaging occurred in 65 patients (46.7 percent), including 25 sterilized lesions (17.9 percent) and 24 minimal residual disease (17.2 percent). In median follow-up of 30 months, none of the patients with sterilized disease developed local or distant recurrence. Among patients with minimal residual disease, none developed local recurrence, whereas two (8.3 percent) developed distant metastasis, and one died from disease. In patients with gross residual disease (Grade 2, 1, 0) the percentage of local recurrence was 8.8 percent, distant recurrence 26.6 percent, and 13.3 percent died from disease. The difference between three groups is statistically significant as regards local and distant recurrence., Conclusions: After preoperative therapy, the sterilized disease shows an excellent prognosis. The minimal residual disease has an important numeric incidence. Its outcome is different, with a not-negligible risk of distant recurrence. The minimal residual disease has a much better prognosis in comparison with the gross residual disease.

Objective: To compare the effects of norepinephrine and metaraminol on hemodynamics in septic shock patients., Design and Setting: Open-label, controlled clinical trial in the general intensive care unit of a university-affiliated hospital., Patients and Participants: Ten consecutive septic shock patients receiving norepinephrine to maintain the mean arterial pressure higher than 65 mmHg., Interventions: Patients were monitored with pulmonary artery catheter and indirect calorimetry. At the baseline hemodynamic variables were obtained during norepinephrine infusion. Subsequently norepinephrine was replaced by metaraminol infusion in a dose sufficient to keep mean arterial pressure constant. After 20 min of stable arterial pressure a new set of measurement was repeated., Measurements and Results: Mean arterial pressure did not differ significantly with norepinephrine or metaraminol; there was no relationship between the norepinephrine and metaraminol doses. Replacement norepinephrine with metaraminol did not modify hemodynamic variables; in particular there were no changes in heart rate, stroke volume index, pulmonary artery occlusion pressure, or oxygen consumption index., Conclusions: This study shows that metaraminol increases arterial pressure as does norepinephrine in septic shock patients. Despite similar effects of norepinephrine and metaraminol, there was no relationship between the dose of the two drugs.

Background: The power of breathing (PoB) is used to estimate the mechanical workload of the respiratory system. Aim of this study was to investigate the effect of different tidal volume-respiratory rate combinations on the PoB when the elastic load is constant. In order to assure strict control of the experimental conditions, the PoB was calculated on an airway pressure-volume curve in mechanically ventilated patients., Methods: Ten patients received three different tidal volume-respiratory rate combinations while minute ventilation was constant. Respiratory mechanics, PoB and its elastic and resistive components were calculated. Alternative methods to estimate the elastic workload were assessed: elastic work of breathing per litre per minute, elastic workload index (the square root of elastic work of breathing multiplied by respiratory rate) and elastic double product of the respiratory system (the elastic pressure multiplied by respiratory rate)., Results: Despite constant elastance and minute ventilation, the elastic PoB showed an increment greater than 200% from the lower to the greater tidal volume, accounting for approximately 80% of the whole PoB increment. On the contrary, elastic work of breathing per litre per minute, elastic workload index and elastic double product did not change., Conclusion: Changes in breathing pattern markedly affect the PoB despite constant mechanical load. Other indexes could assess the elastic workload without tidal volume dependence. Power of breathing use should be avoided to compare different mechanical loads or efficiencies of the respiratory muscles when tidal volume is variable.

Background: The pressure-time product (PTP) is often used to compare conditions with different breathing patterns. Being the pressure-time product calculated with pressures changes over a minute, mechanical load and inspiration time per minute should be its main determinants. The aim of this study was to investigate if the method of PTP computation is affected by the breathing pattern when mechanical load and inspiratory time per minute are constant., Methods: Respiratory mechanics and the PTP developed by the ventilator were calculated in 10 mechanically ventilated patients at three different respiratory rate/tidal volume combinations, provided that minute ventilation and inspiratory time per minute were constant., Results: The static elastance did not change at different tidal volumes. Despite the constant elastic load over a minute, the elastic PTP showed an increment greater than 200% from the higher to the lower respiratory rate, responsible for approximately 80% of the whole PTP increment. On the contrary a 'corrected' elastic PTP (calculated using the square root of the elastic pressure-time area), the elastic double product of the respiratory system and the mean elastic pressure per minute, did not significantly change., Conclusions: Changes in breathing pattern markedly affected the PTP independently by the mechanical load and the inspiratory time per minute. In these conditions it could not correctly estimate the metabolic cost of breathing. The use of a 'corrected' PTP, the mean inspiratory pressure per minute or the double product of the respiratory system, could overcome this limitation.

Study Objective: To compare the frequency of airway seal and sore throat with the LMA-ProSeal (PLMA) and the standard Laryngeal Mask Airway (LMA) during laparoscopic surgery., Design: Prospective, controlled, randomized, nonblinded clinical study., Setting: University-affiliated hospital., Patients: 60 adult, ASA physical status I, II, and III patients undergoing laparoscopic surgery with general anesthesia, without contraindication to the use of the laryngeal mask., Interventions: Patients were randomized to receive mechanical ventilation [tidal volume (V(T)) 7 mL/kg(-1); positive end-expiratory pressure (PEEP) 10 cmH(2)O] through the PLMA or the standard LMA, both equipped with a gastric tube., Measurements: Heart rate, arterial pressure, inspiratory and expiratory V(T), airway pressure, end-tidal CO(2) partial pressure, and pulse oximetry were recorded. The leak fraction was calculated as the difference between the inspiratory and expiratory V(T) divided by the inspiratory V(T). Postoperative sore throat frequency was scored in the recovery room ("early") and 1 week after surgery ("late")., Main Results: All patients were successfully ventilated through the assigned laryngeal mask. The leak fraction was 7 +/- 3% with the LMA and 7 +/- 4% with the PLMA (p = 0.731). In one patient, the PLMA drainage tube was not patent despite a leak fraction of 5%, and there was no clinically detectable air leak. During the recovery room stay, the frequency of sore throat was scored as mild in 13% and 10% of patients with the standard LMA and the PLMA, respectively, and was absent in the remaining patients (p = 0.99, between groups). There were no differences in the frequency of sore throat between the "early" and "late" evaluations (p = 0.99)., Conclusions: The PLMA and the LMA show similar airtight efficiency during laparoscopy. The patency of the PLMA drainage tube should always be confirmed. The sore throat evaluation performed in recovery room appears as reliable as later evaluations.

We describe a case of small bowel obstruction due to prosthetic mesh migration. A 67-year-old male, who had undergone prosthetic repair of inguinal hernia 3 years before, was admitted for a mechanical small bowel obstruction. Laparotomy revealed the penultimate ileal loop choked by an adhesion drawing it towards a polypropylene mesh, firmly attached to the parietal peritoneum of the inguinal region. The intestinal loop was released; the mesh was embedded deep with continuous whip suture after folding the parietal peritoneum. The patient was dismissed on the 11th postoperative day surgically healed. The "tension-free" technique is undoubtedly the gold standard for hernia repair. However, it is not free of complications, mostly due to technical errors, of which the surgeon must be aware, both when he is responsible for correcting defects in the wall, as well as when he has to face an occlusion in a patient who has undergone plastic surgery for inguinal hernia.

Background: The ProSeal Laryngeal Mask Airway (PLMA) ventilation tube is narrower and shorter than the standard Laryngeal Mask Airway (LMA) and is without the vertical bars at the end of the tube. In this randomized, crossover study, PLMA and LMA resistances were compared., Methods: Respiratory mechanics was calculated in 26 anesthetized, mechanically ventilated patients with both LMA and PLMA. The laryngeal mask positioning was fiberoptically evaluated. Differences in the respiratory mechanics of the LMA and the PLMA were attributed to the differences between the laryngeal masks., Results: In the total study population the airway resistance was 1.5 +/- 2.6 hPa.l-1.s-1 (P = 0.005) higher with the PLMA than with the LMA. During the PLMA use, the peak expiratory flow reduced by 0.02 +/- 0.05 l min-1 (P = 0.046), the expiratory resistance increased by 0.6 +/- 1.3 hPa.l-1.s-1 (P = 0.022), and the time constant of respiratory system lengthened by 0.09 +/- 0.18 s (P = 0.023). These differences doubled when the LMA was better positioned than the PLMA, whereas they disappeared when the PLMA was positioned better than the LMA., Conclusions: The standard LMA offers a lower resistive load than the PLMA. Moreover, the fitting between the laryngeal masks and the larynx, as fiberoptically evaluated, plays a major role in determining the resistive properties of these devices.

Introduction: Short bowel disruption following blunt abdominal trauma is rare and hard to diagnose and to treat. Death rate depends both on timing of surgical procedure and on associated lesions., Material and Methods: We show a case of short bowel isolated lesion following fall from mountain bike, III degree in O.I.S. Classification. Abdominopelvic US and helicoidal CT scan were performed, reveling pneumoperitonaeum due to hollow viscus disruption. Surgical procedure was performed within five hours from trauma., Results: No complications occurred in postoperative period. Upper alimentary tract X-ray proved a regular transit, without any fistula. Patient was discharged on 13th day., Conclusion: Laparotomy must not be delayed if there is any doubt about bowel conditions: it's demonstrated that timing of surgical procedure is related to prognosis. If haemodynamic status of the patient allows, careful abdomen CT evaluation is mandatory; adequate nutritional support in postoperative period is also very important.

Background: The ProSeal laryngeal mask airway (PLMA) may have advantages over the laryngeal mask airway (LMA) in obese patients. We tested this hypothesis in a clinical setting., Methods: Sixty obese patients (BMI >30) were randomized to receive mechanical ventilation (tidal volume 7 ml kg(-1), PEEP 10 cm H(2)O), through either the PLMA or the LMA. A gastric tube was used in all patients. Cuff pressure was set at 60 cm H(2)O and increased progressively until excessive leak occurred. The incidence of sore throat was assessed at recovery and after 1 week., Results: The mean leak fraction was 6.1 (SD 2.9)% with the LMA and 6.4 (3.5)% with the PLMA (P=0.721). With the PLMA, with no sign of ventilation problems, the drainage tube was not patent in three patients. The cuff pressure was >100 cm H(2)O in 38% of the LMA group and 7% of the PLMA group (P=0.05). The incidence of sore throat was similar in both groups and it was similarly scored in the recovery room and 1 week after surgery., Conclusions: Both the PLMA and the LMA can be used for mechanical ventilation of obese patients. The patency of the PLMA drainage tube needs to be checked constantly even when an optimal airtight seal is present. In obese patients the LMA requires a greater cuff pressure than the PLMA, but sore throat is not related to the cuff pressure. Sore throat assessment in the recovery room appears as reliable as assessment later.

We describe a dermatofibrosarcoma protuberans (DFSP) of the breast and briefly report about such cases previously mentioned in the literature. A 27-year-old woman was referred because of the progressive increase, during pregnancy, of a mammary nodule located between the internal quadrants of the right breast. Its clinical and radiologic features suggested a fibroadenoma. Lumpectomy revealed a 3-cm, gray-whitish, fasciculated nodule. Histological examination showed a neoplasm characterized by a highly and monomorphic cellular proliferation of spindle-shaped cells, arranged in bundles displaying repetitive storiform growth pattern and infiltrating the adjacent mammary tissue. Lack of necrosis and low mitotic rate was observed. At immunohistochemistry the tumor cells were diffusely positive for vimentin and CD34, but negatively stained with CD99, bc-2, desmin, smooth-muscle actin, S100 protein and cytokeratins. A diagnosis of mammary dermatofibrosarcoma protuberans (DF-SP) was posed. Neoplastic involvement of surgical margins led to a subsequent quadrantectomy without regional lymphadenectomy. The patient was alive and disease-free at the 8-month follow-up. Mammary DFSP is rare. Its preoperative diagnosis is extremely difficult, particularly when radiologic images show an intraparenchymal lesion with round borders. We report such a case and briefly review the pertinent literature. Morphologic parameters to distinguish DFSP from other spindle cell lesions of the breast are discussed.

Background: The tracheal tube (TT) produces reversible bronchoconstriction and increases pulmonary airway resistance compared to the laryngeal mask airway (LMA). The possible persistence of this effect in the postoperative period has not been studied. The aim of this study was to compare the early postoperative pulmonary function in healthy patients undergoing minor surgical procedures with the LMA or with the TT., Methods: Sixty patients scheduled for saphenous vein stripping under general anaesthesia were randomised to receive the LMA or the TT. Before anaesthesia and 20 min after LMA or TT removal, pulse oxymetry values (SpO(2)) were recorded and patients performed forced spirometry in the supine position., Results: Preoperative pulmonary function was normal in both groups. There were no differences between groups in the preoperative respiratory function test and SpO(2). Following surgery SpO(2), forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and peak expiratory flow (PEF) decreased in both groups. The FEV1/FVC did not change in either of the groups. In the TT group, compared to patients using the LMA, there was a greater relative decrease of SpO(2) (2.7 +/- 2.7% vs. 1.3 +/- 2.2%, P=0.017), FEV1 (17.6 +/- 12.2% vs. 8 +/- 17.4%, P=0.008), FVC (15.8 +/- 12.4% vs. 9 +/- 13.4%, P=0.023) and PEF (20.6% +/- 15.3% vs. 8.1 +/- 33.3%, P=0.033)., Conclusions: This study demonstrates greater early postoperative respiratory restrictive syndrome and lower arterial oxygen saturation following tracheal intubation compared to LMA use in patients without respiratory disease.

Between 1997 and 2000, black dot of potato (Solanum tuberosum L.), caused by the polyphagous soilborne fungus Colletotrichum coccodes (Wallr.) Hughes, was observed each summer in fields located in Umbria (central Italy). Disease incidence ranged from 50 to 100%, and early potato cultivars were generally more susceptible than late-maturing ones. Disease symptoms were first observed during August as a yellowing and wilting of foliage in the tops of plants, followed by rotting of the roots and stems, which led to the premature death of 50 to 70% of plants. Setose1 sclerotia (300 to 500 mm in diameter) and acervuli of the fungus were found on roots and stems of infected plants. Acervuli produced hyaline, aseptate, cylindrical conidia (16 to 22 × 2.5 to 4.5 μm) formed on unicellular cylindrical phialidic conidiophores. The fungus was isolated from diseased stems and roots on potato dextrose agar (PDA) at pH 6.5. Pathogenicity of the fungus was confirmed by fulfilling Koch's postulates using 3- to 4-week-old potato plants of a local cultivar. A superficial 5-mm vertical cut was made with a scalpel into the base of potato stems (2 cm beneath the soil surface), and 5-mm-diameter plugs of PDA alone (control plants) or PDA plus fungal growth were placed over the cuts. The wounds were sealed with wet cotton swabs that were held in place with Parafilm. Symptoms that resembled those in the field were observed on inoculated plants 6 to 8 weeks postinoculation. Symptoms did not appear on the control plants. The same fungus was reisolated from the diseased plants. Based on morphological characteristics of sclerotia, acervuli, and conidia, as well as pathogenicity tests, the fungus was identified as C. coccodes. To our knowledge, this is the first report of C. coccodes as the causal agent of black dot of potato in central Italy. We did not observe foliar outbreaks of the disease, which were reported from the United States (2). In both 1921 (1) and 1951 (3), the fungus was reported to cause severe outbreaks of the disease in northern Italy. Since then, its presence in Italy has been rarely recorded in potato (4). The occurrence of extremely dry and hot weather conditions during the summers of 1997 to 2000, which are favorable for disease development, made the disease particularly severe. We cannot exclude the possibility that the disease may have been present in central Italy before our observations, as it can be misdiagnosed and its symptoms can be masked by the symptoms of other diseases. The significance of black dot in central Italy needs to be reappraised in terms of both yield loss and tuber quality. References: (1) C. Arnaudi. Atti Ist. Bot. Univ. Pavia. Ser. 3, 1:71, 1924. (2) A. W. Barkdoll and J. R. Davis. Plant Dis. 76:131, 1992. (3) G. Goidanich. Inf. Fitopatol. 1:5, 1951. (4) S. Vitale et al. J. Plant Pathol. 80:265, 1998.

Endorectal sonography may significantly help to evaluate rectal lymphoma. We report the sonographic findings in a case of rectal non-Hodgkin's MALT (mucosa-associated lymphoid tissue) lymphoma, including the monitoring of response to therapy and confirmation of recurrence, in a 45-year-old man. On endorectal sonography of the rectal wall, the mucosa was markedly thickened to 1.1 cm and was diffusely hypoechoic and risen into multiple polypoid folds. The submucosa and muscularis propria appeared normal. Multiple lymph nodes were visualized in the perirectal fat; they were homogeneously hypoechoic, were round or oval, and ranged from 1.0 cm to 2.6 cm. Endoscopic biopsies revealed a grade I non-Hodgkin's MALT lymphoma. Following chemotherapy, endorectal sonography showed that the surface of the rectal mucosa had a smoother appearance and near-normal thickness, but lymph nodes, although smaller, remained visible in the perirectal fat. Four months later, endorectal sonography demonstrated a local relapse of disease, with significant thickening of the rectal mucosa and multiple lymph nodes visible in the perirectal fat. Following high-dose chemotherapy for the recurrence, endorectal sonography demonstrated a near-normal appearance of the rectal mucosa., (Copyright 2001 John Wiley & Sons, Inc.)

Study Objective: To quantify the impact on peak airway pressure of pressure-controlled and volume-controlled ventilation during Laryngeal Mask Airway (LMA) use., Design: Prospective, crossover clinical study., Setting: University-affiliated hospital., Patients: 32 ASA physical status I and II patients undergoing general anesthesia with the LMA., Interventions: Patients were ventilated for three minutes both with pressure-controlled and volume-controlled ventilation, provided that tidal volume (V(T) ) and inspiratory time (It) were constant., Measurements and Main Results: The monitored parameters were electrocardiography, arterial blood pressure, pulse oximetry, capnography, neuromuscular transmission, airway pressure and flow, and concentration of ventilated vapors and gases. The actually delivered V(T) was similar with both types of ventilation (volume-controlled = 0.67 +/- 0.13 lt, pressure-controlled = 0.67 +/- 0.14 lt; p = 0.688). Peak airway pressure was lower during pressure-controlled ventilation (14.6 +/- 3.5 cmH(2)O) than during volume-controlled ventilation (16 +/- 4 cmH(2)O) (p < 0.001). Furthermore, we noted that the higher the airway pressure with volume-controlled ventilation, the greater was the reduction in airway pressure during pressure-controlled ventilation., Conclusions: Pressure-controlled rather than volume-controlled ventilation can improve the effectiveness of mechanical ventilation in patients with high airway pressure.

Background and Objective: Few and conflicting data are available regarding the changes of plasma potassium concentration during acute respiratory acidosis in human beings. This study compares the acute changes in plasma potassium concentration in acutely hypercapnic patients and in non-hypercapnic patients during general anaesthesia., Methods: Thirty-three patients undergoing interventional rigid bronchoscopy were studied. Ventilation of the lungs was randomly conducted using either spontaneous-assisted ventilation or intermittent negative-pressure ventilation. All patients received the same anaesthetic protocol. Arterial blood gases and osmolality, and plasma concentrations of glucose, sodium, potassium and chloride were measured., Results: Intraoperatively, PaCO2 was higher during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (9 +/- 1.8 vs. 5.4 +/- 1.2 kPa, P < 0.001) and the pH was also lower during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (7.24 +/- 0.07 vs. 7.4 +/- 0.08, P < 0.001). Plasma potassium concentration remained similar in both groups (3.8 +/- 0.2 mmol L(-1) with spontaneous-assisted ventilation vs. 3.7 +/- 0.4 mmol L(-1) with intermittent negative-pressure ventilation)., Conclusion: Acute respiratory acidosis does not affect plasma potassium concentration.