Search

Positive end-expiratory pressure (PEEP) can potentially modulate inspiratory effort (ΔPes), which is the major determinant of self-inflicted lung injury. Does high PEEP reduce ΔPes in patients with moderate-to-severe ARDS on assisted ventilation? Sixteen patients with Pa o 2 /F io 2 ≤ 200 mm Hg and ΔPes ≥ 10 cm H 2 O underwent a randomized sequence of four ventilator settings: PEEP = 5 cm H 2 O or PEEP = 15 cm H 2 O + synchronous (pressure support ventilation [PSV]) or asynchronous (pressure-controlled intermittent mandatory ventilation [PC-IMV]) inspiratory assistance. ΔPes and respiratory system, lung, and chest wall mechanics were assessed with esophageal manometry and occlusions. PEEP-induced alveolar recruitment and overinflation, lung dynamic strain, and tidal volume distribution were assessed with electrical impedance tomography. ΔPes was not systematically different at high vs low PEEP (pressure support ventilation: median, 20 cm H 2 O; interquartile range (IQR), 15-24 cm H 2 O vs median, 15 cm H 2 O; IQR, 13-23 cm H 2 O; P =.24; pressure-controlled intermittent mandatory ventilation: median, 20; IQR, 18-23 vs median, 19; IQR, 17-25; P =.67, respectively). Similarly, respiratory system and transpulmonary driving pressures, tidal volume, lung/chest wall mechanics, and pendelluft extent were not different between study phases. High PEEP resulted in lower or higher ΔPes, respiratory system driving pressure, and transpulmonary driving pressure according to whether this increased or decreased respiratory system compliance (r = −0.85, P <.001; r = −0.75, P <.001; r = −0.80, P <.001, respectively). PEEP-induced changes in respiratory system compliance were driven by its lung component and were dependent on the extent of PEEP-induced alveolar overinflation (r = −0.66, P =.006). High PEEP caused variable recruitment and systematic redistribution of tidal volume toward dorsal lung regions, thereby reducing dynamic strain in ventral areas (pressure support ventilation: median, 0.49; IQR, 0.37-0.83 vs median, 0.96; IQR, 0.62-1.56; P =.003; pressure-controlled intermittent mandatory ventilation: median, 0.65; IQR, 0.42-1.31 vs median, 1.14; IQR, 0.79-1.52; P =.002). All results were consistent during synchronous and asynchronous inspiratory assistance. The impact of high PEEP on ΔPes and lung stress is interindividually variable according to different effects on the respiratory system and lung compliance resulting from alveolar overinflation. High PEEP may help mitigate the risk of self-inflicted lung injury solely if it increases lung/respiratory system compliance. ClinicalTrials.gov ; No.: NCT04241874; URL: www.clinicaltrials.gov [Display omitted] [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Patients with severe respiratory failure due to COVID‐19 who are not under mechanical ventilation may develop severe hypoxemia when complicated with spontaneous pneumomediastinum (PM). These patients may be harmed by invasive ventilation. Alternatively, veno‐venous (V‐V) extracorporeal membrane oxygenation (ECMO) may be applied. We report on the efficacy of V‐V ECMO and invasive ventilation as initial advanced respiratory support in patients with COVID‐19 and acute respiratory failure due to spontaneous PM.This was a retrospective cohort study performed between March 2020 and January 2022. Enrolled patients had COVID‐19 and acute respiratory failure due to spontaneous PM and were not invasively ventilated. Patients were treated in the intensive care unit (ICU) with invasive ventilation (invasive ventilation group) or V‐V ECMO support (V‐V ECMO group) as the main therapeutic option. The primary outcomes were mortality and ICU discharge at 90 days after ICU admission.Twenty‐two patients were included in this study (invasive ventilation group: 13 [59%]; V‐V ECMO group: 9 [41%]). The V‐V ECMO strategy was significantly associated with lower mortality (hazard ratio [HR] 0.33 [95% CI 0.12–0.97], p = 0.04). Five (38%) patients in the V‐V ECMO group were intubated and eight (89%) patients in the invasive ventilation group required V‐V ECMO support within 30 days from ICU admission. Three (33%) patients in the V‐V ECMO group were discharged from ICU within 90 days compared to one (8%) patient in the invasive ventilation group (HR 4.71 [95% CI 0.48–45.3], p = 0.18).Preliminary data suggest that V‐V ECMO without invasive ventilation may improve survival in COVID‐19‐related acute respiratory failure due to spontaneous PM. The study's retrospective design and limited sample size underscore the necessity for additional investigation and warrant caution. [ABSTRACT FROM AUTHOR]

• Machine learning-based prediction models can catalog, classify, and correlate large amounts of multimodal data to aid clinicians at diagnostic, prognostic, and therapeutic levels. • A variety of the prediction models, prediction intervals, and prediction windows were identified to facilitate timely diagnosis of ventilator-associated pneumonia (VAP). • There is a need for dynamic machine learning models using time-depended predictors to predict real-time risk of VAP and related outcomes. Machine learning-based prediction models can catalog, classify, and correlate large amounts of multimodal data to aid clinicians at diagnostic, prognostic, and therapeutic levels. Early prediction of ventilator-associated pneumonia (VAP) may accelerate the diagnosis and guide preventive interventions. The performance of a variety of machine learning-based prediction models were analyzed among adults undergoing invasive mechanical ventilation. This systematic review and meta-analysis was conducted in accordance with the Cochrane Collaboration. Machine learning-based prediction models were identified from a search of nine multi-disciplinary databases. Two authors independently selected and extracted data using predefined criteria and data extraction forms. The predictive performance, the interpretability, the technological readiness level, and the risk of bias of the included studies were evaluated. Final analysis included 10 static prediction models using supervised learning. The pooled area under the receiver operating characteristics curve, sensitivity, and specificity for VAP were 0.88 (95 % CI 0.82–0.94, I2 98.4 %), 0.72 (95 % CI 0.45–0.98, I2 97.4 %) and 0.90 (95 % CI 0.85–0.94, I2 97.9 %), respectively. All included studies had either a high or unclear risk of bias without significant improvements in applicability. The care-related risk factors for the best performing models were the duration of mechanical ventilation, the length of ICU stay, blood transfusion, nutrition strategy, and the presence of antibiotics. A variety of the prediction models, prediction intervals, and prediction windows were identified to facilitate timely diagnosis. In addition, care-related risk factors susceptible for preventive interventions were identified. In future, there is a need for dynamic machine learning models using time-depended predictors in conjunction with feature importance of the models to predict real-time risk of VAP and related outcomes to optimize bundled care. [ABSTRACT FROM AUTHOR]

Background: During Pressure Support Ventilation (PSV) an inspiratory hold allows to measure plateau pressure (Pplat), driving pressure (∆P), respiratory system compliance (Crs) and pressure-muscle-index (PMI), an index of inspiratory effort. This study aims [1] to assess systematically how patient's effort (estimated with PMI), ∆P and tidal volume (Vt) change in response to variations in PSV and [2] to confirm the robustness of Crs measurement during PSV. Methods: 18 patients recovering from acute respiratory failure and ventilated by PSV were cross-randomized to four steps of assistance above (+ 3 and + 6 cmH2O) and below (-3 and -6 cmH2O) clinically set PS. Inspiratory and expiratory holds were performed to measure Pplat, PMI, ∆P, Vt, Crs, P0.1 and occluded inspiratory airway pressure (Pocc). Electromyography of respiratory muscles was monitored noninvasively from body surface (sEMG). Results: As PSV was decreased, Pplat (from 20.5 ± 3.3 cmH2O to 16.7 ± 2.9, P < 0.001) and ∆P (from 12.5 ± 2.3 to 8.6 ± 2.3 cmH2O, P < 0.001) decreased much less than peak airway pressure did (from 21.7 ± 3.8 to 9.7 ± 3.8 cmH2O, P < 0.001), given the progressive increase of patient's effort (PMI from -1.2 ± 2.3 to 6.4 ± 3.2 cmH2O) in line with sEMG of the diaphragm (r = 0.614; P < 0.001). As ∆P increased linearly with Vt, Crs did not change through steps (P = 0.119). Conclusion: Patients react to a decrease in PSV by increasing inspiratory effort—as estimated by PMI—keeping Vt and ∆P on a desired value, therefore, limiting the clinician's ability to modulate them. PMI appears a valuable index to assess the point of ventilatory overassistance when patients lose control over Vt like in a pressure-control mode. The measurement of Crs in PSV is constant—likely suggesting reliability—independently from the level of assistance and patient's effort. [ABSTRACT FROM AUTHOR]

Diaphragm ultrasound (DU) has been used in adult and pediatric critical patients in relation to prediction of extubation success or to detect diaphragm dysfunction, but there is a lack of evidence in neonates. Our aim is to study the evolution of diaphragm thickness in preterm infants, as well as related variables. This prospective monocentric observational study included preterm infants born before 32 weeks (PT32). We performed DU to measure right and left inspiratory and expiratory thickness (RIT, LIT, RET, and LET) and calculated the diaphragm-thickening fraction (DTF) in the first 24 h of life and then weekly until 36 weeks postmenstrual age, death, or discharge. Using multilevel mixed-effect regression, we evaluated the influence of time since birth on diaphragm measurements, as well as bronchopulmonary dysplasia (BPD), birth weight (BW), and days of invasive mechanical ventilation (IMV). We included 107 infants, and we performed 519 DUs. All diaphragm thickness increased with time since birth, but the only additional variable that influenced this growth was BW: beta coefficients RIT = 0.00006; RET = 0.00005; LIT = 0.00005; and LET = 0.00004, p < 0.001. Right DTF values remained stable since birth but left DTF increased with time only in infants with BPD. Conclusion: In our population we found that the higher the BW, the higher diaphragm thicknesses at birth and follow-up. Contrary to the previously published findings in adult and pediatric settings, we were unable to describe a relationship between days of IMV and diaphragm thickness in PT32. The final diagnosis of BPD does not influence this increase either, but it does increase left DTF. What is Known: • Diaphragm thickness and diaphragm thickening fraction have been related to the time on invasive mechanical ventilation in adults and pediatric patients, as well as with extubation failure. • Very few evidence is yet available on the use of diaphragmatic ultrasound in preterm infants. What is New: • Birth weight is the only variable related to diaphragm thickness in preterm infants born before 32 weeks postmenstrual age. • Days of invasive mechanical ventilation do not influence diaphragm increase in thickness in preterm infants. [ABSTRACT FROM AUTHOR]

Background: A specific magnesium level is essential to be maintained to ensure appropriate neuromuscular excitability and cardiac function; an increase or decrease in its levels usually leads to critical abnormality. Hypomagnesemia in critically ill patients has many potential ramifications and is found to be an important factor in hindering their recovery. Thus, the study aimed to assess the serum magnesium levels in critically ill participants and explore its effect on their condition. Methods: A prospective observational study was conducted for 21 months, from February 2019 to October 2020, among all critically ill participants admitted to the medical intensive care unit (ICU) of a tertiary care hospital. The Acute Physiology and Chronic Health Evaluation II score questionnaire was used to determine the severity of their condition and blood samples were collected within 24 h of their ICU admission for analysis. Results: One hundred participants were enrolled, of which 40% were between the age group of 46 and 65 years and 71% were males. Among all participants with hypomagnesemia, 52% were diabetic, 19% had a history of alcohol use disorder, and 27% had normal calcium and potassium levels. Hypomagnesemia significantly correlated with a longer duration of ICU stay among participants. Conclusion: A significant correlation was observed between hypomagnesemia and increased ICU length of stay and mortality but not the duration of mechanical ventilation. Monitoring and appropriate supplementation of serum magnesium is recommended to limit further comorbidity and mortality in the critical care setting. [ABSTRACT FROM AUTHOR]

Background: Evidence and recommendations for hygiene management in home mechanical ventilation (HMV) are rare. In Germany, few regionally limited studies show poor hygiene management or a lack of its implementation. This scoping review of international literature identified the evidence in hygiene management for ventilated patients in the home care setting which has to be implemented for infection prevention and control. Methods: A review of international literature was conducted in CINAHL, PubMed and Web of Science. The search focused on four key domains: HMV, hygiene management, home care setting, and methicillin-resistant Staphylococcus aureus (MRSA). Data of included studies were extracted using a data charting sheet. Extracted data were assigned to the categories (1) study description, (2) setting and participants, and (3) hygiene management. Results: From 1,718 reviewed articles, n = 8 studies met inclusion criteria. All included studies had a quantitative study design. The approaches were heterogeneous due to different settings, study populations and types of ventilation performed. Regarding aspects of hygiene management, most evidence was found for infectious critical activities (n = 5), quality management for hygiene (n = 4), and training and education (n = 4). This review identified research gaps concerning kitchen hygiene, relatives and visitors of HMV patients, and waste management (n = 0). Discussion: Overall evidence was rather scarce. Consequently, this review could not answer all underlying research questions. No evidence was found for measures in hygiene management relating to ventilated patients' relatives. Evidence for kitchen hygiene, waste management and interaction with relatives is available for inpatient care settings. However, this may not be transferable to outpatient care. Binding legal requirements and audits may help regulate the implementation of HMV hygiene measures. Conclusion: Infection control programmes included qualified personnel, hygiene plans, and standards for MRSA and multidrug-resistant organisms (MDRO). The appropriateness of hygiene management measures for outpatient care is the basis for their application in practice. [ABSTRACT FROM AUTHOR]

Background: Evidence and recommendations for hygiene management in home mechanical ventilation (HMV) are rare. In Germany, few regionally limited studies show poor hygiene management or a lack of its implementation. This scoping review of international literature identified the evidence in hygiene management for ventilated patients in the home care setting which has to be implemented for infection prevention and control.Methods: A review of international literature was conducted in CINAHL, PubMed and Web of Science. The search focused on four key domains: HMV, hygiene management, home care setting, and methicillin-resistant Staphylococcus aureus (MRSA). Data of included studies were extracted using a data charting sheet. Extracted data were assigned to the categories (1) study description, (2) setting and participants, and (3) hygiene management.Results: From 1,718 reviewed articles, n = 8 studies met inclusion criteria. All included studies had a quantitative study design. The approaches were heterogeneous due to different settings, study populations and types of ventilation performed. Regarding aspects of hygiene management, most evidence was found for infectious critical activities (n = 5), quality management for hygiene (n = 4), and training and education (n = 4). This review identified research gaps concerning kitchen hygiene, relatives and visitors of HMV patients, and waste management (n = 0).Discussion: Overall evidence was rather scarce. Consequently, this review could not answer all underlying research questions. No evidence was found for measures in hygiene management relating to ventilated patients' relatives. Evidence for kitchen hygiene, waste management and interaction with relatives is available for inpatient care settings. However, this may not be transferable to outpatient care. Binding legal requirements and audits may help regulate the implementation of HMV hygiene measures.Conclusion: Infection control programmes included qualified personnel, hygiene plans, and standards for MRSA and multidrug-resistant organisms (MDRO). The appropriateness of hygiene management measures for outpatient care is the basis for their application in practice. [ABSTRACT FROM AUTHOR]

The objective of this prospective randomised clinical study was to determine the differences in the tracheal, oesophageal and rectal temperature in spontaneously breathing or mechanically ventilated dogs. A total of thirty dogs were allocated to the SPO-group breathing spontaneously (n = 15) or the MEC-group ventilated mechanically (n = 15). Anaesthesia was established using a medetomidine-butorphanol-propofol-isoflurane combination. The tracheal (T-Tra), oesophageal (T-Oes), rectal (T-Rec), inspired gas (T-Gas), room (T-Room) temperatures, respiratory frequency (fR), heart rate (HR), mean arterial pressure (MAP) and end-tidal carbon dioxide concentration (ETCO2) were measured after connecting to a re-breathing system (baseline) and subsequently in 10-minute intervals for 60 minutes. The data were analysed using ANOVA and Steel-Dwass tests (P < 0.05). In the SPO-group, the T-Tra, was significantly lower at T30, T40, T50, T60, the T-Oes and T-Rec at T40, T50, T60, compared to the baseline. In the MEC-group, the T-Tra and T-Oes was significantly lower at T30, T40, T50, T60, the T-Rec at T40, T50, T60, compared to the baseline. In the SPO-group, the fR was significantly lower for all the times and the ETCO2 higher at T10, T20, T30, T40, T50 compared to the MEC-group. No other differences were detected. During anaesthesia, there is a comparable decrease in body temperatures, regardless of whether the dogs are breathing spontaneously or ventilated mechanically. [ABSTRACT FROM AUTHOR]

Purpose: Air pollutant exposure constitutes a serious risk factor for the emergence or aggravation of (existing) pulmonary disease. The impact of pre-intensive care ambient air pollutant exposure on the duration of artificial ventilation was, however, not yet established.Methods: The medical records of 2003 patients, admitted to the intensive care unit (ICU) of the Antwerp University Hospital (Flanders, Belgium), who were artificially ventilated on ICU admission or within 48 h after admission, for the duration of at least 48 h, were analyzed. For each patient's home address, daily air pollutant exposure [particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM2.5) and ≤ 10 µm (PM10), nitrogen dioxide (NO2) and black carbon (BC)] up to 10 days prior to hospital admission was modeled using a high-resolution spatial-temporal model. The association between duration of artificial ventilation and air pollution exposure during the last 10 days before ICU admission was assessed using distributed lag models with a negative binomial regression fit.Results: Controlling for pre-specified confounders, an IQR increment in BC (1.2 µg/m3) up to 10 days before admission was associated with an estimated cumulative increase of 12.4% in ventilation duration (95% CI 4.7-20.7). Significant associations were also observed for PM2.5, PM10 and NO2, with cumulative estimates ranging from 7.8 to 8.0%.Conclusion: Short-term ambient air pollution exposure prior to ICU admission represents an unrecognized environmental risk factor for the duration of artificial ventilation in the ICU. [ABSTRACT FROM AUTHOR]

Purpose: To describe the variability and determinants of the effect of extracorporeal CO2 removal (ECCO2R) on tidal volume (Vt), driving pressure (ΔP), and mechanical power (PowerRS) and to determine whether highly responsive patients can be identified for the purpose of predictive enrichment in ECCO2R trial design.Methods: Using data from the SUPERNOVA trial (95 patients with early moderate acute respiratory distress syndrome), the independent effects of alveolar dead space fraction (ADF), respiratory system compliance (Crs), hypoxemia (PaO2/FiO2), and device performance (higher vs lower CO2 extraction) on the magnitude of reduction in Vt, ΔP, and PowerRS permitted by ECCO2R were assessed by linear regression. Predicted and observed changes in ΔP were compared by Bland-Altman analysis. Hypothetical trials of ECCO2R, incorporating predictive enrichment and different target CO2 removal rates, were simulated in the SUPERNOVA study population.Results: Changes in Vt permitted by ECCO2R were independently associated with ADF and device performance but not PaO2/FiO2. Changes in ΔP and PowerRS were independently associated with ADF, Crs, and device performance but not PaO2/FiO2. The change in ΔP predicted from ADF and Crs was moderately correlated with observed change in ΔP (R2 0.32, p < 0.001); limits of agreement between observed and predicted changes in ΔP were ± 3.9 cmH2O. In simulated trials, restricting enrollment to patients with a larger predicted decrease in ΔP enhanced the average reduction in ΔP, increased predicted mortality benefit, and reduced sample size and screening size requirements. The increase in statistical power obtained by restricting enrollment based on predicted ΔP response varied according to device performance as specified by the target CO2 removal rate.Conclusions: The lung-protective benefits of ECCO2R increase with higher alveolar dead space fraction, lower respiratory system compliance, and higher device performance. ADF and Crs, rather than severity of hypoxemia, should be the primary factors determining whether to enroll patients in clinical trials of ECCO2R. [ABSTRACT FROM AUTHOR]

Objective: To explore the applicative effect of laryngeal mask and endotracheal intubation for patients with respiratory failure in the pre-hospital care and emergency treatment. Methods: 92 cases of patients with respiratory failure who were rescued by emergency medicine department in The 174th Hospital of PLA from January 2016 to May 2018 were selected.All patients were divided into group A and group B according to different ventilation methods. Group A were used laryngeal mask artificialventilation to carry out pre-hospital care, it had a total of 47 cases. Group B were used endotracheal intubation and artificial ventilation to carry out pre-hospital care, it had a total of 45 cases. The vital signs of respiratory rate(RR), heart rate(HR) and blood oxygen saturation (SpO2) were compared between the two groups before treatment and 1h after treatment. The time of laryngeal mask and endotracheal intubation, one-time success rate and success rate of cardiopulmonary resuscitation were compared, and the complications of the two groups were recorded. Results: There was no significant difference in HR,RR and SpO2 between the two groups before treatment (P>0.05). 1 h after treatment, the HR and RR in the two groups were lower than before treatment, the SpO2 was higher than before treatment(P<0.05). 1 h after treatment, there was no significant difference in HR, RR and SpO2 between the two groups (P>0.05). The laryngeal mask insertion time in group A was significantly shorter than group B, and the one-time success rate in group A was obviously higher than group B, the differences between the two groups were statistically significant (P<0.05). There was no significant difference in the success rate of cardiopulmonary resuscitation between the two groups(P>0.05). The incidence of complications in group A were 2.13%(1/47), were lower than 13.33%(6/45) in group B, and the differences were statistically significant(P<0.05). Conclusion: The effect of laryngeal mask ventilation and endotracheal intubation ventilation is basically the same, but the operation is simpler and safer, it can shorten the insertion time of intubation, increase the one-time success rate, and strive for rescue time. [ABSTRACT FROM AUTHOR]

Aim: From 2014 to 2015, studies were conducted on the use of a closed contour of artificial circulation on the basis of the National Research Center for Cardiac Surgery in the city of Astana, Kazakhstan.\The purpose of this study was to evaluate how effective the closed and open contours of artificial circulation in reducing the risk of post-operative complications. Methods: The study included 100 patients who underwent surgery for stable angina pectoris of coronary heart disease; they underwent coronary artery bypass surgery. Group 1 included 50 patients, with an average age of 62 ± 8 years, undergoing coronary artery bypass grafting using a closed contour of artificial circulation. Group 2 included 50 patients, with an average age of 62 ± 7 years, underwent aortocoronary bypass using an open contour of artificial circulation. For all the initial indices of the group were homogeneous. The time of aortic clamping in both groups was the same, indicating that the same surgeons performed the operation. Total time of artificial circulation was less in the first group than in the second group (57 min ± 12.5 and 64 min ± 16.7, respectively; P = 0.04), because the reperfusion time was less in Group 1 (20.2 min ± 7 and 23.9 min ± 9, respectively; P = 0.04). The average number of grafts was 3 ± 0.67 in the control group, 3 ± 0.53 in the comparative group. Post-operative analysis of laboratory indicators was taken 6 h after operation. Results: The level of erythrocytes in the first group by the end of 6 h after operation was higher, than in the second group 4.13 × 1012 ± 0.59 and 3.38 × 1012 ± 0.52 (P = 0.001), respectively; the level of hemoglobin (Hb) was 115.04 g/L ± 14.7 and 104.1 g/L ± 11.26 (P = 0.05), respectively; the level of hematocrit was 33.1 ± 3.89 and 29.89 ± 4.06 (P = 0.001), respectively; the level of platelets was 246 ±52 and 199 ± 40 (P = 0.001), respectively; leukocytes, C-reactive protein (CRP) levels, body temperature, respiratory rate, and heart rate are reduction in the first group: The level of leukocytes was 11.67 × 109 ± 3.8 and 14.02 × 109 ± 4.3 (P = 0.03), respectively; the level of CRP was 1.4 mg/dl ± 2.4 and 2.2 mg/dl ± 1.9 (P = 0.04), respectively; body temperature was 36.7 ± 0.33 and 38.1±0.7 (P = 0.01), respectively; respiratory rate in 1 min was 17 ± 1.6 and 20 ± 2.02 (P = 0.01), respectively; and heart rate in 1 min was 69 ± 11 and 75 ± 15 (P = 0.02), respectively. Stay by day of the patient in the hospital in the first group was also less and was 10.14 ± 3.8 and 11.32 ± 4.2 (P = 0.04), respectively. The time the patient spent on artificial ventilation in the first group was less, 486 min ± 125 and 646 ± 213 (P = 0.01), respectively. Conclusion: The closed contour can be confidently applied to patients with complex concomitant diseases, as the risk of a systemic inflammatory response decreases, and the level of red blood remains higher in comparison with the open contour of the artificial circulation. [ABSTRACT FROM AUTHOR]

The objective of this study is to determine the incidence of post-extubation acute laryngeal lesions in a pediatric intensive care unit (PICU) and potential risk factors. Children, aged 28 days to 5 years, admitted to the PICU who required endotracheal intubation for at least 24 h were enrolled. Exclusion criteria were a previous intubation, history of laryngeal disease, current or past tracheostomy, the presence of craniofacial malformations and patients considered on palliative care. All patients underwent flexible fiber-optic laryngoscopy (FFL) not later than 8 h after extubation. A blinded researcher identified and classified laryngeal lesions based on recorded media. 231 children were enrolled between November 2005 and December 2015. At FFL examination, 102 children (44.15%) presented moderate to severe laryngeal lesions. On a multivariable analysis, we found that for each additional day with repositioning of the endotracheal tube, there was an increase of 7.3% (RR 95% CI 1.012-1.137; P = 0.018) on the baseline risk of developing moderate to severe acute laryngeal lesions. Furthermore, for each additional dose of sedation per day of intubation, there was also an increase of 3.5% on the same baseline risk (RR 95% CI 1.001-1.070; P = 0.041). The amount of tube repositioning episodes and the need for extra doses of sedation (as a proxy for possible agitation) were found to be associated with acute laryngeal lesions. Adequate sedation and minimized tube repositioning should be pursued to possibly prevent the development of post-extubation airway compromise. [ABSTRACT FROM AUTHOR]

Objective: Aim of this study was to investigate retrospectively, the intensive care mortality rates and predictors of mortality in patients over 65 years who were admitted to intensive care units of a training and research hospital with acute respiratory failure due to chronic obstructive pulmonary disease (COPD). Material and Methods: One hundred seventeen cases who were admitted between 1 January 2009 - 1 May 2016 were enrolled in this retrospective study. Patients data were collected from hospital's electronic data management system and analyzed with computer based statistical calculation program SPSS 21. Comparison of measurable data with normal distribution was made by t-test. Mann Whitney U-test was performed to compare parameters without normal distribution. Chi-square test was used to compare qualitative data. Multivariable logistic regression analysis was performed for parameters to determine risk factors for mortality. For all analyzes, p<0,05 was accepted significant. Results: Mean age of the patients included in the study was 75.9±6.4. Fifty of the cases (42,7%) were women. Of the cases, 93 (79,4%) were accepted from the emergency department, 17 (14,5%) from another center and 7 (6,1%) from the clinic. The mean length of stay in intensive care unit was 28.6±32.2 days. Most common comorbidities were hypertension (39.3%), chronic renal failure (17.9%) and diabetes mellitus (17.1%). Forty-one (35%) of the cases had Glasgow Coma Score <8 at the admission to the intensive care unit. The mean APACHE II Score was 26.4±7.3 and the intensive care mortality rate was 50 percent. Age of the patients (p=0.012), Glasgow Coma Score <8 (p=0.005) and vazopressor requirement (p<0.001) were found to be statistically significant in univariate analysis. Glasgow Coma Score (p=0.001) and vazopressor requirement (p<0.001) were found to be significant in the multivariate logistic regression analysis. The causes of death were ventilator related pneumonia/sepsis in 47 (79.7%), heart failure in 9 (15.3%), myocardial infarction in 2 (3.4%), and pneumothorax in 1 (1.6%). Conclusion: Considering the increase in the geriatric population, the Glasgow Coma Score and vasopressor requirement seem to be two useful parameters for predicting prognosis of patients with acute exacerbation of COPD in this age group. [ABSTRACT FROM AUTHOR]

Objectives: In mechanical ventilation, normoventilation in terms of PCO2 can be achieved by titration of the respiratory rate and/or tidal volume. Although a linear relationship has been found between changes in respiratory rate and resulting changes in end-tidal cO2 (△PetCO2) as well as between changes in respiratory rate and equilibration time (teq) for mechanically ventilated patients without lung injury, it is unclear whether a similar relationship holds for acute lung injury or altered hemodynamics.Design: We performed a prospective randomized controlled animal study of the change in PetCO2 with changes in respiratory rate in a lung-healthy, lung-injury, lung-healthy + altered hemodynamics, and lung-injury + altered hemodynamics pig model.Setting: University research laboratory.Subjects: Twenty mechanically ventilated pigs.Interventions: Moderate lung injury was induced by injection of oleic acid in 10 randomly assigned pigs, and after the first round of measurements, cardiac output was increased by approximately 30% by constant administration of noradrenalin in both groups.Measurements and Main Results: We systematically increased and decreased changes in respiratory rate according to a set protocol: +2, -4, +6, -8, +10, -12, +14 breaths/min and awaited equilibration of Petco2. We found a linear relationship between changes in respiratory rate and △PetCO2 as well as between changes in respiratory rate and teq. A two-sample t test resulted in no significant differences between the lung injury and healthy control group before or after hemodynamic intervention. Furthermore, exponential extrapolation allowed prediction of the new PetCO2 equilibrium and teq after 5.7 ± 5.6 min.Conclusions: The transition between PetCO2 equilibria after changes in respiratory rate might not be dependent on moderate lung injury or cardiac output but on the metabolic production or capacity of cO2 stores. Linear relationships previously found for lung-healthy patients and early prediction of PetCO2 equilibration could therefore also be used for the titration of respiratory rate on the PetCO2 for a wider range of pathologies by the physician or an automated ventilation system. [ABSTRACT FROM AUTHOR]

Accurate monitoring of flow rate and volume exchanges is essential to minimize ventilator-induced lung injury. Mechanical ventilators employ flowmeters to estimate the amount of gases delivered to patients and use the flow signal as a feedback to adjust the desired amount of gas to be delivered. Since flowmeters play a crucial role in this field, they are required to fulfill strict criteria in terms of dynamic and static characteristics. Therefore, mechanical ventilators are equipped with only the following kinds of flowmeters: linear pneumotachographs, fixed and variable orifice meters, hot wire anemometers, and ultrasonic flowmeters. This paper provides an overview of these sensors. Their working principles are described together with their relevant advantages and disadvantages. Furthermore, the most promising emerging approaches for flowmeters design (i.e., fiber optic technology and three dimensional micro-fabrication) are briefly reviewed showing their potential for this application. [ABSTRACT FROM AUTHOR]

Background: Medical officers frequently need to initiate the management of critically ill patients requiring endotracheal intubation and mechanical ventilation. The knowledge of hospital-based medical officers at a South African secondary hospital was evaluated on indications for endotracheal intubation and the initiation of mechanical ventilation in adults (defined as persons aged 13 years and older). Method: Data were collected through questionnaires using 18 multiple-choice questions. Questionnaires consisted of a short test on the basic principles of intubation and the initiation of mechanical ventilation. Results: Forty-four medical officers participated in this study, conducted in 2008. The mean test score for medical officers taking the test was 6.2, with a range of 2-10, out of a possible 15 marks. 77.3% of participants answered fewer than half of the questions correctly. Nobody answered more than 70% of the questions correctly. More than two thirds of the medical officers could not correctly identify indications for endotracheal intubation, 97.7% of medical officers could not correctly identify all of the contraindications to orotracheal intubation, and 97.7% were unable to choose appropriate initial ventilator settings. Conclusion: Most medical officers at this secondary hospital were lacking in essential knowledge needed to make decisions on which patients required intubation and how to initiate mechanical ventilation. Pre- and postgraduate training on these basic principles needs to improve. [ABSTRACT FROM AUTHOR]

Highlights: [•] Capnogram changes are studied in response to methacholine at different ventilatory frequencies. [•] Respiratory resistance and reactance are measured by the forced oscillation technique at 8Hz. [•] Capnogram time derivatives identified the bronchoconstriction even at high breathing rate. [•] Capnogram and time derivatives correlated significantly with respiratory reactance and/or resistance. [•] The capnogram may thus be useful to diagnose airway obstruction in young children. [ABSTRACT FROM AUTHOR]

Context: Non-invasive ventilation for people with chronic obstructive pulmonary disease is performed at home, after a brief period of training in the hospital setting, leaving the patient responsible for managing and executing it according to their medical prescription. Objectives: to build a theoretical framework of the process of adherence to a therapeutic regimen in chronic illness, on the basis of users and their family caregivers. The methodology used corresponds to Grounded Theory, originally developed by Glaser and Strauss. The principles and rules of open coding, axial coding and selective coding were used in data analysis. Results: the adherence of people with COPD to their therapeutic regimen takes place in a context of multidisciplinary intervention. Conclusion: nurses should be aware of strategies that require familiar support and involvement, knowledge acquisition and evaluation of the difficulties and benefits of implementing the therapy. [ABSTRACT FROM AUTHOR]

We describe the incidence and practice of prone positioning and determined the association of use of prone positioning with outcomes in invasively ventilated patients with acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19) in a national, multicenter observational study, performed at 22 intensive care units in the Netherlands. Patients were categorized into 4 groups, based on indication for and actual use of prone positioning. The primary outcome was 28-day mortality. Secondary endpoints were 90-day mortality, and ICU and hospital length of stay. In 734 patients, prone positioning was indicated in 60%—the incidence of prone positioning was higher in patients with an indication than in patients without an indication for prone positioning (77 vs. 48%, p = 0.001). Patients were left in the prone position for median 15.0 (10.5–21.0) hours per full calendar day—the duration was longer in patients with an indication than in patients without an indication for prone positioning (16.0 (11.0–23.0) vs. 14.0 (10.0–19.0) hours, p < 0.001). Ventilator settings and ventilation parameters were not different between the four groups, except for FiO2 which was higher in patients having an indication for and actually receiving prone positioning. Our data showed no difference in mortality at day 28 between the 4 groups (HR no indication, no prone vs. no indication, prone vs. indication, no prone vs. indication, prone: 1.05 (0.76–1.45) vs. 0.88 (0.62–1.26) vs. 1.15 (0.80–1.54) vs. 0.96 (0.73–1.26) (p = 0.08)). Factors associated with the use of prone positioning were ARDS severity and FiO2. The findings of this study are that prone positioning is often used in COVID-19 patients, even in patients that have no indication for this intervention. Sessions of prone positioning lasted long. Use of prone positioning may affect outcomes. [ABSTRACT FROM AUTHOR]

Background and objective Acute severe clinical deterioration of patients with cystic fibrosis ( CF) may mandate endotracheal intubation. The benefits of intubation were evaluated by examining which pre-admission parameters were associated with intensive care unit ( ICU) outcome and assessing the potential benefits of intubation for survivors in terms of time from ICU discharge to death. Methods A retrospective analysis of data from a single centre was undertaken. Results Thirty patients required intubation on 34 occasions (8 per 1000 admissions). Eleven patients died in ICU and 7 after ICU but not hospital discharge. Fifty-nine per cent of 22 patients intubated for pneumothorax and/or haemoptysis survived to hospital discharge. Of the twelve intubated for infective exacerbations, 33% survived to hospital discharge. Those who died after hospital discharge survived 447 days. There were no significant differences for survivors in reasons for intubation, colonizing organism, frequency of infective exacerbations, severity of illness or pulmonary physiology. Osteoporosis and a greater fall in body mass index over the 24 months prior were more frequent in non-survivors. Conclusions Patients with CF developing haemoptysis and/or pneumothorax should be admitted to ICU and intubated promptly, should this be required. Chronic disease markers may be more relevant prognostically than rates of hospitalization or forced expiratory volume in 1 s decline which should not be bars to invasive ventilation. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to detect the rate of follow-up with the latest information and the current level of knowledge held by medical personnel working in different medical fields about Basic Life Support (BLS). Methods The study group consisted of healthcare personnel working the in the province of Izmir. Three groups were designated as the sample groups according to their field of work. The survey questionnaires were prepared in accordance with the updates of Universal BLS guidelines, and they were presented to the study groups during face to face interviews. Results The evaluation of the current knowledge level of the medical personnel about BLS revealed that the knowledge rate of medical personnel on "the rate of cardiac massage and artificial ventilation" was detected as highest, whereas the rate of medical personnel's ability on ranking application steps was the lowest. Knowledge of health professional groups working in the field of pre-hospital emergency care about BLS was found to be statistically significantwhen compared to that of professional groups working in other medical fields. Conclusions The rate of medical personnels' following up with the latest information about Basic Life Support (BLS) is low. There are differences in the current level of knowledge between sample groups established according to their fields of work. [ABSTRACT FROM AUTHOR]

Being a patient in an intensive care unit can be extremely stressful. As well as having to cope with being critically ill, patients are subjected to an environment that can cause acute anxiety and confusion. This article describes the importance of the role of learning disability nurses in helping patients and their families to cope with this unfamiliar and demanding situation. [ABSTRACT FROM AUTHOR]

Abstract: Many patients undergo long-term artificial ventilation and their respiratory system mechanics should be monitored to detect changes in the patient''s state and to optimize ventilator settings. In this work the most popular algorithms for tracking variations of respiratory resistance (R rs ) and elastance (E rs ) over a ventilatory cycle were analysed in terms of systematic and random errors. Additionally, a new approach was proposed and compared to the previous ones. It takes into account an exact description of flow integration by volume-dependent lung compliance. The results of analyses showed advantages of this new approach and enabled to form several suggestions. Algorithms including R rs and E rs dependencies on airflow and lung volume can be effectively applied only at low levels of noise present in measurement data, otherwise the use of the simplest model with constant parameters is preferable. Additionally, one should avoid including the resistance dependence on airflow alone, since this considerably destroys the retrieved trace of R rs . Finally, the estimated cyclic trajectories of R rs and E rs are more sensitive to noise present in pressure than in the flow signal, and the elastance traces are estimated more accurately than the resistance ones. [Copyright &y& Elsevier]

Abstract: We describe the underlying theory, design and experimental evaluation of an electromechanical analogue infant lung to simulate spontaneous breathing patterns of preterm infants. The aim of this work is to test the possibility to obtain breathing patterns of preterm infants by taking into consideration the air compressibility. Respiratory volume function represents the actuation pattern, and pulmonary pressure and flow-rate waveforms are mathematically obtained through the application of the perfect gas and adiabatic laws. The mathematical model reduces the simulation interval into a step shorter than 1ms, allowing to consider an entire respiratory act as composed of a large number of almost instantaneous adiabatic transformations. The device consists of a spherical chamber where the air is compressed by four cylinder-pistons, moved by stepper motors, and flows through a fluid-dynamic resistance, which also works as flow-rate sensor. Specifically designed software generates the actuators motion, based on the desired ventilation parameters, without controlling the gas pneumatic parameters with a closed-loop. The system is able to simulate tidal volumes from 3 to 8ml, breathing frequencies from 60 to 120bpm and functional residual capacities from 25 to 80ml. The simulated waveforms appear very close to the measured ones. Percentage differences on the tidal volume waveform vary from 7% for the tidal volume of 3ml, down to 2.2–3.5% for tidal volumes in the range of 4–7ml, and 1.3% for the tidal volume equal to 8ml in the whole breathing frequency and functional residual capacity ranges. The open-loop electromechanical simulator shows that gas compressibility can be theoretically assessed in the typical pneumatic variable range of preterm infant respiratory mechanics. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the ability of atorvastatin pretreatment on the improvement of alveolar capillary hemodynamics and permeability, and on the protection of lung injury induced by high-stretch mechanical respiration. It applies the treatment on 24 secluded groups of normal rabbit lungs three days before the surgery, wherein lungs were ventilated for one hour. Results show that the high-pressure-no support group obtained more injury compared with low-pressure groups.

Abstract: The implementation of artificial ventilation schemes is necessary when respiration fails. One approach involves the application of high frequency oscillatory ventilation (HFOV) to the respiratory system. Oscillatory airflow in the upper bronchial tree can be characterized by Reynolds numbers as high as 104, hence, the flow presents turbulent features. In this study, transitional and turbulent flow within an asymmetric bifurcating model of the upper airway during HFOV are studied using large eddy simulation (LES) methods. The flow, characterized by a peak Reynolds number of 8132, is analysed using a validated LES model of a three-dimensional branching geometry. The pressures, velocities, and vorticity within the flow are presented and compared with prior models for branching flow systems. The results demonstrate how pendelluft occurs at asymmetric branches within the respiratory system. These results may be useful in optimising treatments using HFOV methods. [Copyright &y& Elsevier]

Abstract: This study classifies the mode of ventilation using respiratory rate, inhaled and exhaled carbon dioxide concentrations in anaesthetised patients. Thirty seven patients were breathing spontaneously (SPONT) and 50 were on a ventilator (intermittent positive pressure ventilation, IPPV). A data-based methodology for rule inference from trained neural networks, orthogonal search-based rule extraction, identified two sets of low-order Boolean rules for differential identification of the mode of ventilation. Combining both models produced three possible outcomes; IPPV, SPONT and ‘Uncertain’. The true positive rates were approximately maintained at 96% for IPPV and 93% for SPONT, with false positive rates of 0.4% for each category and 4.3% ‘Uncertain’ inferences. [Copyright &y& Elsevier]

Abstract: Rapid airway occlusions during mechanical ventilation are followed immediately by high-frequency pressure oscillations. To answer the question if the frequency of forced pressure oscillations is an indicator for partial obstruction of the endotracheal tube (ETT) we performed mathematical simulations and studies in a ventilated physical lung model. Model-derived predictions were evaluated in seven healthy volunteers. Partial ETT obstruction was mimicked by decreasing the inner diameter (ID) of the ETT. In the physical model ETTs of different ID were used. In spontaneously breathing volunteers viscous fluid was applied into the ETT''s lumen. According to the predictions derived from mathematical simulations, narrowing of the ETT''s ID from 9.0 to 7.0mm decreased the frequency of the pressure oscillations by 11% while changes of the respiratory system''s compliance had no effect. In volunteers, a similar reduction (10.9%) was found when 5ml fluid were applied. We conclude that analysis of pressure oscillations after flow interruption offers a tool for non-invasive detection of partial ETT obstruction. [Copyright &y& Elsevier]

Objectives – A review is given on various methods, preconditions and pitfalls of apnea testing for the diagnosis of brain death. Materials and methods – An extensive medical data base search was implemented by information gathered from books and our own experience with more than 2000 apnea tests. Results – While testing for apnea (AT) is considered indispensable worldwide, recommendations and handling differ. Rather than relying on elapsed time, a specific target value for the partial arterial pressure of carbon dioxide (PaCO2) should be aimed at being the maximum physiological stimulus for respiration. Methodological points are elaborated upon in detail for apneic oxygenation and hypoventilation. Conclusion – AT is an indispensable element of diagnosing brain death. Although with proper handling and adequate precautions AT is safe, it should be performed as a last resort. An international agreement on target values for the PaCO2 is desirable. [ABSTRACT FROM AUTHOR]

The mortality rate associated with respiratory failure due to invasive fungal infections after allogeneic hematopoietic stem cell transplantation (HSCT) is exceedingly high. We present a retrospective analysis of 4 HSCT recipients who survived long-term artificial respiration subsequent to pulmonary mycosis, and compare our current findings with historic data. Several clinical parameters indicate a remarkable improvement in the clinical courses of those patients in recent years: weaning time, extubation rate, and improvement of additional organ failures were all significantly better in patients treated after the emergence of new antimycotic agents, resulting in prolonged overall survival. We propose that our observations reflect an improved management of these patients, mainly because of the use of new antimycotics with alternative mechanisms of action and decreased toxicity, allowing for earlier, more aggressive, and more effective antifungal treatment approaches. In addition, the optimized use of new technologies designed to augment spontaneous breathing efforts by patients, mechanical ventilation, as well as the advantages of early tracheotomy will contribute to better outcomes in the treatment of respiratory failure due to pulmonary mycoses following allogeneic HSCT. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of mechanical ventilation on alveolar fibrinolytic capacity.Design and Setting: Randomized controlled animal study in 66 Sprague-Dawley rats.Subjects and Interventions: Test animals received intratracheal fibrinogen and thrombin instillations; six were killed immediately (fibrin controls), and the others were allocated to three ventilation groups (ventilation period: 225 min) differing in positive inspiratory pressure and positive end-expiratory pressure, respectively: group 1, 16 cmH2O and 5 cmH2O (n=17); group 2, 26 cmH2O and 5 cmH2O (n=16); group 3, 35 cmH2O and of 5 cmH2O (n=17). Ten animals that had not been ventilated served as healthy controls.Measurements and Results: After animals were killed, we measured D-dimers, plasminogen activator inhibitor (PAI) 1, and tumor necrosis factor alpha in the bronchoalveolar lavage fluid and calculated lung weight and pressure/volume (P/V) plots. The median D-dimer concentration (mg/l) decreased with increasing pressure amplitude (192 in group 1, IQR 119; 66 in group 2, IQR 107; 29 in group 3, IQR 30) while median PAI-1 (U/ml) increased (undetectable in group 1; 0.55 in group 2, IQR 4.55; 3.05 in group 3, IQR 4.85). PAI-1 level was correlated with increased lung weight per bodyweight (Spearman's rank correlation 0.708). Tumor necrosis factor alpha concentration was not correlated with PAI-1 level.Conclusions: Alveolar fibrinolytic capacity is suppressed during mechanical ventilation with high pressure amplitudes due to local production of PAI-1. [ABSTRACT FROM AUTHOR]

Abstract: Background: In spite of progress in science of medicine, the tetanus neonatal still exists in third world countries. Objective: to describe epidemiological, clinical features, treatment and evolution of the tetanus at new-borns in our experience. Materials and Methods: retrospective survey of 34 cases of tetanus neonatal in neonate intensive care of the children’s hospital in Rabat (Morocco) between 1990 and 2003. We analysed: the progress of pregnancy and the mother''s antitetanus vaccination, the conditions of delivery and the newborn''s contamination, the clinical picture, the treatment and the evolution. Results: pregnancies are not controlled in 70%. Nine percent of the women received two injections of antitetanus vaccination. The delivery produced at home in 56% of the cases. The septic section of the cord has been observed in 56% of the cases and the application of substances on the cord in 35% of the cases. The delay of consultation was on average of three days (1-10 days). The mean score of “Rhéa” was 4,3 and the mean score of “Patel and Jocq” was 3,5. The treatment was essentially sedation and mechanical ventilation. The main complication was the nosocomial pneumopathy (53%). The rate of death was 62%. Conclusion: the sanitary education lack increases the tetanus neonatal. This affection remains fatal. Currently, only the prevention is efficient. [Copyright &y& Elsevier]

Abstract: The article objective is to raise the main lines for quality control in artificial ventilation in order to: 1) insure the quality and the security of care delivered to the patients; 2) satisfy the authorized requirements, in order to make them evolve. The entire survey rests on the patient physiological criteria’s with a particular focus about the patient’s comfort and survival compatibility conditions. A bibliographic research and staffing with physicians and physiologists permitted to deduct: 1) a physiological load notebook in terms of respiratory quality care: to ensure vital needs; 2) a clinical load notebook: to ensure the quality and the safety of ventilation; 3) a technical load notebook: Showing the good communication between the needs expressed by the doctors and the technological industrial answers. In order to maintain artificial ventilation performances, maintenances of the quality control are achieved periodically. This hierarchical proposal of control points to check during a preventive maintenance and a quality control in ventilation is proposed. The technical and organizational solutions proposed in the process of the maintenance and quality control permits to insure the patient’s security and quality of care. [Copyright &y& Elsevier]

A non-invasive and simple method of parameter estimation has been developed for the model-based decision support of the artificial ventilation in intensive care units. The parameter concerned was the respiratory shunt. Originally, the shunt had to be estimated using a numerical algorithm, which was slow and unreliable. The estimation process also required the knowledge of other parameters, whose values could only be obtained using invasive monitoring equipment. In this paper, the respiratory index is used for the shunt estimation. A linear regression model and a non-linear adaptive neuro-fuzzy inference system (ANFIS) model were used to describe the relationship between the respiratory index and the shunt. The shunts estimated using these models were then used to calculate the fractional inspired oxygen needed to attain the target arterial oxygen level of the model patient. The advisor also utilises population median values of the cardiac index and oxygen consumption index. This alleviates the need for invasive monitoring. In a simulation study, the mean squared error of the control using the ANFIS model was 0.75 kPa2 compared to 2.06 kPa2 using the linear regression model. Therefore, the performance of the FiO2 advisor was better when the shunt was estimated using the non-linear ANFIS model. [Copyright &y& Elsevier]

Objective: To measure the impact of changes in the fraction of inspired oxygen (FiO2) on systemic and cerebral oxygen supply in gas and liquid ventilated healthy animals.Design: Interventional prospective animal study.Setting: University research laboratory.Participants: Ten healthy, new-born piglets.Interventions: Variations in FiO2 during conventional mechanical ventilation (CMV) followed by partial liquid ventilation (PLV) with two different filling volumes of PF 5080 (10 vs. 30 ml/kg).Measurements and Results: Arterial blood gases were obtained 15 min after changing FiO2 and concentrations of cerebral oxygenated and total hemoglobin were determined with near infrared spectroscopy. During CMV an increase in FiO2 1.0 was associated with a constant rise in PaO2 but only a small increase in the cerebral concentration of oxygenated Hb. Initiation of PLV (at FiO2 of 1.0) caused a rapid drop in PaO2 towards values that were similar to CMV at FiO2 of 0.5. At FiO2 of 0.5 a reduction in oxygenated Hb was found in the 30 ml/kg filling group. Complete filling of the lungs with PFC caused a significant drop in total cerebral Hb concentration. CONCLUSIONS. According to our data, PLV in healthy lungs should be performed with a FiO2 of 1.0 and a small filling volume to avoid deterioration in cerebral oxygen supply. [ABSTRACT FROM AUTHOR]

Objective: To estimate the effect of artificial ventilation on regional cerebral blood flow, cardiovascular regulation, and cerebral oxidative metabolism in newborns.Design and Subjects: Comparison of three randomized treatment groups of newborn piglets: Group 1 (artificially ventilated sham-operated group; n =7); group 2 (artificially ventilated group with normoxia and moderate normocapnic hypoxia; n =7); group 3 (spontaneously breathing group with normoxia and moderate normocapnic hypoxia; n =6).Measurements and Results: Animals were anesthetized with 0.5% isoflurane in 70% nitrous oxide and 30% oxygen. Groups 1 and 2 were artificially ventilated. Animals in group 3 breathed spontaneously. Moderate normocapnic hypoxia was induced in groups 2 and 3 for 1 h by lowering the inspiratory oxygen fraction from 0.35 to 0.11. Mode of ventilation induced at most marginal effects on global cerebrovascular response, cardiovascular regulation, and cerebral oxidative metabolism. However, under normoxic conditions, regional cerebral blood flow of the medulla oblongata, pons, mesencephalon, thalamus, and cerebellum were markedly reduced in artificially ventilated piglets ( P <0.05). Moderate normocapnic hypoxia led to a marked increase in regional cerebral blood flow, which was significantly lower in the medulla oblongata, pons, mesencephalon, thalamus, and cerebellum of artificially ventilated piglets ( P <0.05).Conclusion: Artificial ventilation clearly induces reduced neuronal activity in the brain stem and cerebellum of newborn piglets. This is suggested by a considerably reduced blood flow in these regions under normoxia and moderate normocapnic hypoxia. However, there is no relevant detrimental effect on cardiovascular regulation and brain oxidative metabolism. [ABSTRACT FROM AUTHOR]

Mechanical stress during ventilation may cause or aggravate acute lung injury. This study investigates the influence of low vs. high tidal volume (Vt) on factors known to play key roles in acute lung injury: nitric oxide release, eNOS and iNOS gene expression, lipid peroxidation (LPO), and surfactant phospholipids (PL). Isolated rabbit lungs were subjected to one of three ventilation patterns for 135 min (Vt-PEEP): 6 ml/kg–0 cm H2O. 12 ml/kg–0 cm H2O 6 ml/kg–5 cm H2O, 12 ml/kg–0 cm H2O, and 6 ml/kg–5 cm H2O resulted in comparable peak inspiratory pressure (PIP). This allowed comparing low and high Vt without dependence on PIP. Ventilatory patterns did not induce changes in pulmonary artery pressure, vascular permeability (Kf,c), PIP or pulmonary compliance. High Vt in comparison with both of the low Vt groups caused an increase in BALF-nitrite (30.6±3.0* vs. 21.4±2.2 and 16.2±3.3 μM), BALF-PL (1110±19* vs. 750±68 and 634±82 μg/ml), and tissue LPO product accumulation (0.62±0.051* vs. 0.48±0.052 and 0.43±0.031 nmol/mg), *P<0.05 each. Perfusate nitrite and BALF-PL composition (assessed by use of 31P-NMR spectroscopy and MALDI-TOF mass spectrometry) did not differ among the groups. High Vt ventilation reduced eNOS gene expression but did not affect iNOS expression. The increased release of NO and the accumulation of LPO products may represent early lung injury while elevated BALF-PL may reflect distension-induced surfactant secretion. [Copyright &y& Elsevier]

Ventilator settings influence the development and outcome of acute lung injury. This study investigates the influence of low versus high tidal volume (Vt) on oxidative stress-induced lung injury.Isolated rabbit lungs were subjected to one of three ventilation patterns (Vt–positive end-expiratory pressure, PEEP): LVZP (6 ml/kg–0 cm H2O), HVZP (12 ml/kg–0 cm H2O), LV5P (6 ml/kg–5 cm H2O). These ventilation patterns allowed a comparison between low and high Vt without dependence on peak inspiratory pressure (PIP). Infusion of hypochlorite (1000 nmol/min) or buffer (control) was started at t=0 min. Pulmonary artery pressure (PAP), PIP and weight were continuously recorded. Capillary filtration coefficient [Kf,c (10−4 ml s−1 cm H2O−1 g−1)] was gravimetrically determined (−15/30/60/90/120 min).PIP averaged 5.8±0.6/13.9±0.6/13.9±0.4 cm H2O in the LVZP, HVZP and LV5P groups. PIP, Kf,c or PAP did not change in control groups, indicating that none of the ventilation patterns caused lung injury by themselves. Hypochlorite-induced increase in Kf,c but not hypochlorite-induced increase in PAP, was significantly attenuated in the LVZP-/LV5P- versus the HVZP-group (Kf,c,max. 1.0±0.23/1.4±0.40 versus 3.2±1.0*). Experiments with hypochlorite were terminated due to excessive edema (>50 g) at 97±2.2/94.5±4.5 min in the LVZP-/LV5P-group versus 82±3.8* min in the HVZP-group (*: P<0.05).Low Vt attenuated oxidative stress-induced increase in vascular permeability independently from PIP and PEEP. [Copyright &y& Elsevier]

We present a case study of machine learning and data mining in intensive care medicine. In the study, we compared different methods of measuring pressure–volume curves in artificially ventilated patients suffering from the adult respiratory distress syndrome (ARDS). Our aim was to show that inductive machine learning can be used to gain insights into differences and similarities among these methods. We defined two tasks: the first one was to recognize the measurement method producing a given pressure–volume curve. This was defined as the task of classifying pressure–volume curves (the classes being the measurement methods). The second was to model the curves themselves, that is, to predict the volume given the pressure, the measurement method and the patient data. Clearly, this can be defined as a regression task. For these two tasks, we applied C5.0 and CUBIST, two inductive machine learning tools, respectively. Apart from medical findings regarding the characteristics of the measurement methods, we found some evidence showing the value of an abstract representation for classifying curves: normalization and high-level descriptors from curve fitting played a crucial role in obtaining reasonably accurate models. Another useful feature of algorithms for inductive machine learning is the possibility of incorporating background knowledge. In our study, the incorporation of patient data helped to improve regression results dramatically, which might open the door for the individual respiratory treatment of patients in the future. [Copyright &y& Elsevier]

Objective:In order to evaluate the pulmonary congestive state of patients being mechanically ventilated, an acetylene rebreathing method was employed. Measurement of pulmonary tissue volume by the acetylene (C2H2) rebreathing method was performed in 15 patients under artificial ventilation including four congestive heart failure cases, one renal failure case, and 12 healthy controls. Methodology: The subjects rebreathed mixed gas containing 0.65% C2H2, 10% argon (Ar), and 60% oxygen (O2) from end-tidal level, and inspiratory and expiratory gas concentrations were measured by a mass spectrometer. Correction for system volume reduction during rebreathing due to gas exchange and C2H2 concentration fluctuation was performed, pulmonary tissue volume was calculated from the C2H2 and Ar concentration difference at the time zero intercept. Time zero was assumed to be the time at which C2H2 and Ar concentration started to differ. Results: Pulmonary tissue volume per functional residual capacity and pulmonary tissue volume per pulmonary capillary blood flow for cases with congestive heart failure and renal failure cases were significantly higher than those for non-pulmonary congestion cases and normal controls. Conclusion: The measurement of pulmonary tissue volume by C2H2 rebreathing can be applied to the patients under artificial ventilation in order to quantitatively evaluate pulmonary congestion or edema. [ABSTRACT FROM AUTHOR]

Patients with severe lung injury usually have a high respiratory drive, resulting in intense inspiratory effort that may even worsen lung damage by several mechanisms gathered under the name "patient-self inflicted lung injury" (P-SILI). Even though no clinical study has yet demonstrated that a ventilatory strategy to limit the risk of P-SILI can improve the outcome, the concept of P-SILI relies on sound physiological reasoning, an accumulation of clinical observations and some consistent experimental data. In this review, we detail the main pathophysiological mechanisms by which the patient's respiratory effort could become deleterious: excessive transpulmonary pressure resulting in over-distension; inhomogeneous distribution of transpulmonary pressure variations across the lung leading to cyclic opening/closing of nondependent regions and pendelluft phenomenon; increase in the transvascular pressure favoring the aggravation of pulmonary edema. We also describe potentially harmful patient-ventilator interactions. Finally, we discuss in a practical way how to detect in the clinical setting situations at risk for P-SILI and to what extent this recognition can help personalize the treatment strategy. [ABSTRACT FROM AUTHOR]

We describe the practice of ventilation and mortality rates in invasively ventilated normal-weight (18.5 ≤ BMI ≤ 24.9 kg/m2), overweight (25.0 ≤ BMI ≤ 29.9 kg/m2), and obese (BMI > 30 kg/m2) COVID-19 ARDS patients in a national, multicenter observational study, performed at 22 intensive care units in the Netherlands. The primary outcome was a combination of ventilation variables and parameters over the first four calendar days of ventilation, including tidal volume, positive end–expiratory pressure (PEEP), respiratory system compliance, and driving pressure in normal–weight, overweight, and obese patients. Secondary outcomes included the use of adjunctive treatments for refractory hypoxaemia and mortality rates. Between 1 March 2020 and 1 June 2020, 1122 patients were included in the study: 244 (21.3%) normal-weight patients, 531 (47.3%) overweight patients, and 324 (28.8%) obese patients. Most patients received a tidal volume < 8 mL/kg PBW; only on the first day was the tidal volume higher in obese patients. PEEP and driving pressure were higher, and compliance of the respiratory system was lower in obese patients on all four days. Adjunctive therapies for refractory hypoxemia were used equally in the three BMI groups. Adjusted mortality rates were not different between BMI categories. The findings of this study suggest that lung-protective ventilation with a lower tidal volume and prone positioning is similarly feasible in normal-weight, overweight, and obese patients with ARDS related to COVID-19. A patient's BMI should not be used in decisions to forgo or proceed with invasive ventilation. [ABSTRACT FROM AUTHOR]

The relationship between artificial ventilation, cardiovascular status, and operant conditioning in the curarized rat was investigated in a series of studies. Two respiratory parameters, peak inspiratory pressure (PIP) and respiratory rate (RR), were sequentially altered in curarized rats while heart rate and variability, and mean blood pressure were recorded. Heart rate increases or decreases were also rewarded in curarized rats ventilated at differing PIP values, 20 cm H[sub2]O or 12 cm H[sub2]O. Heart rate and variability were also recorded in non-curarized rats. At PIP 12, heart rate and variability in the curarized rat was very similar to that or the non-curarized rat. These subjects responded to operant contingencies. Subjects ventilated at PIP 20, however, showed elevated, invariant, and unresponsive heart rates. Ventilation therefore, proved an important determinant of cardiovascular status and conditionability in the curarized rat. RR was not related to heart rate or variability. Neither PIP nor RR affected blood pressure. [ABSTRACT FROM AUTHOR]

Various criteria for weaning patients from ventilators in intensive care have been widely published. These criteria are increasingly incorporated into guidelines, protocols, and more recently, care pathways. We present a case where a patient's lungs were ventilated for 4 days with an infective exacerbation of chronic obstructive pulmonary disease (COPD). We successfully weaned off mechanical ventilation and rapidly extubated the patient's trachea utilizing deep sevoflurane anesthesia. Published weaning indices suggest that this would have been an inappropriate course of action at the time. However, our patient clearly benefited and avoided the need for tracheostomy and prolonged ventilation. [ABSTRACT FROM AUTHOR]

A two-year-old male Labrador was presented with cobra bite. Soon after arrival, the dog developed general muscular weakness and respiratory muscle paralysis. Manual artificial ventilation was initiated immediately and maintained, to support the life of the dog. Polyvalent antivenom could be administered only after three-and-a-half hours, because of not available in nearby vicinity. Muscular paralysis prevailed even after administering two vials of antivenom. Two doses of anticholinesterase drug were then given and the dog regained normal spontaneous muscular activity. The life of the dog was thus supported on manual artificial ventilation for 8½ hrs and anticholinesterase was found effective in reversing the respiratory muscle paralysis. To conclude, antivenom administration alone should not be relied upon in cases of cobra envenomation in dogs. Artificial ventilation should be employed to support the life when there is delay in administering antivenom and anticholinesterase drug should be given to reverse the respiratory muscle paralysis. [ABSTRACT FROM AUTHOR]

The article presents a case study of an infant with cystic fibrosis (CF). The symptoms of a respiratory tract infection observed on the patient are cited. The results of the arterial blood gases in air and chest radiograph are presented as well as the observations on his ventilation requirements. The study suggests that the lungs of the infant with CF are able to tolerate severe infection and a period of prolonged ventilation but are capable of showing considerable recovery.