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Extracorporeal membrane oxygenation (ECMO) is used for most severe acute respiratory distress syndrome cases in specialized centers. Hemocompatibility of devices depends on the size and modification of blood contacting surfaces as well as blood flow rates. An interventional lung assist using arteriovenous perfusion of a low-resistance oxygenator without a blood pump (Novalung, Hechingen, Germany) or a miniaturized ECMO with reduced filling volume and a diagonal blood pump (Deltastream, Medos AG, Stolberg, Germany) could optimize hemocompatibility. The aim of the study was to compare hemocompatibility with conventional ECMO. Female pigs were connected to extracorporeal circulation for 24 h after lavage induced lung injury (eight per group). Activation of coagulation and immune system as well as blood cell damage was measured. A P value <0.05 was considered significant. Plasmatic coagulation was slightly activated in all groups demonstrated by increased thrombin-anti-thrombin III-complex. No clinical signs of bleeding or thromboembolism occurred. Thrombelastography revealed decreased clotting capacities after miniaturized ECMO, probably due to significantly reduced platelet count. These resulted in reduced dosage of intravenous heparin. Scanning electron microscopy of oxygenator fibers showed significantly increased binding and shape change of platelets after interventional lung assist. In all groups, hemolysis remained negligible, indicated by low plasma hemoglobin concentration. Interleukin 8 and tumor necrosis factor-alpha concentration as well as leukocyte count remained unchanged. Both devices demonstrated adequate hemocompatibility for safe clinical application, although a missing blood pump did not increase hemocompatibility. Further studies seem necessary to analyze the influence of different blood pumps on platelet drop systematically.

Objective: In conventional in vivo microscopy, a three dimensional illustration of tissue is lacking. Concerning the microscopic analysis of the pulmonary alveolar network, surgical preparation of the thorax and fixation of the lung is required to place the microscope's objective. These effects may have influence on the mechanical behaviour of alveoli. Relatively new methods exist for in vivo microscopy being less invasive and enabling an observation without fixation of the lung. The aim of this study was to compare a fibered confocal laser scanning microscopy (FCLSM) with optical coherence tomography (OCT) in a mouse and a rabbit model. Moreover, FCLSM was also used endoscopically in the rabbit model., Methods: Smallest possible thoracic windows were excised at the lower margin of the upper right lung lobe and an interpleural catheter inserted before re-coverage with a transparent membrane foil. The OCT-scanner was positioned by a motor driven translation stage. The imaging was gated to endinspiratory plateau. For CLSM, Fluorescein 0.1% was given into the central venous streak line. The confocal probe with a diameter of 650 microm was carefully positioned at the very same lung region. Images were directly recorded real-time and the observed region qualitatively compared with FD-OCT images. Additionally, in the rabbit model, CLSM was used endoscopically under bronchoscopic sight control. In a postprocessing analysis, images taken were analyzed and compared by using an "air index" (AI)., Results: In the mouse model, the very same region could be re-identified with both techniques. Concerning alveolar shape and size, qualitatively comparable images could be gained. The AI was 40.5% for the OCT and 40.1% for the CLSM images. In the rabbit, even an endoscopic view on alveoli was possible. Likewise AI was 43.2% for CLSM through the thoracic window and 43.6% from endoscopically. For the OCT an AI of 44.6% was analysed in the rabbit model., Conclusions: Both FD-OCT and CLSM provide high-resolution images of alveolar structure giving depth information that is beneficial to conventional microscopy. CLSM also facilitates endoscopic view on alveoli being well comparable to images gained through a thoracic window.

Purpose: Although animal studies document conflicting data on the influence of hypothermia on cytokine release in various settings, no data exist if hypothermia affects the inflammatory response after successful cardiopulmonary resuscitation., Materials and Methods: Arrest- and treatment-related variables of 71 patients were documented, and serum samples were analyzed for levels of interleukin 6, tumor necrosis factor-alpha, C-reactive protein, and procalcitonin immediately after hospital admission and after 6, 24, and 120 hours. At day 14, patients were dichotomized in those with good and bad neurological outcome., Results: Regardless of outcomes, interleukin 6 levels were significantly elevated by the use of hypothermia (n = 39). The rate of bacterial colonization was significantly higher in hypothermic patients (64.1 vs 12.5 %; P < .001). On the contrary, procalcitonin levels were, independent of the use of hypothermia, only significantly elevated in patients with bad neurological outcome. Hypothermic patients showed a strong trend to reduced mortality. However, there was no influence on neurological recovery., Conclusions: In this observational study, hypothermia influenced the inflammatory response after cardiopulmonary resuscitation and lead to a higher rate of bacterial colonization without altering ultimate neurologic recovery.

Background: In study, we investigated the effects of different tidal volumes on cerebral tissue oxygenation and cerebral metabolism in a porcine model of acute lung injury (ALI). We hypothesized that mechanical ventilation with low tidal (LT) volumes improves cerebral tissue oxygenation and metabolism after experimentally induced ALI., Methods: After inducing experimental ALI by surfactant depletion, we studied two conditions in 10 female pigs: 1) LT volume ventilation with 6 mL/kg body weight, and 2) high tidal (HT) volume ventilation with 12 mL/kg body weight. Variables of gas exchange, hemodynamic, continuous cerebral tissue oxygen tension (p(ti)O2), cerebral microdialysis, and systemic cytokines were analyzed. After induction of ALI, data were collected at 2, 4, and 8 h. The primary end point was the change in p(ti)O2. For group comparisons, a t-test was used. A value of <0.05 was considered to indicate statistical significance., Results: At baseline and after induction of ALI, no differences between groups were found in p(ti)O2; however, p(ti)O2 was significantly lower in the HT group after 4 and 8 h. PaO2 and PaCO2 showed no significant differences between the groups at all timepoints. Regarding cerebral microdialysis, a significantly higher level of extracellular lactate could be demonstrated after 2, 4, and 8 h in the HT group. The release of cytokines resulted in higher values for interleukin-6 and interleukin-8 in the HT group., Conclusion: Protective ventilation with LT yielded a significant improvement in cerebral tissue oxygenation and metabolism compared to HT ventilation in a porcine model of ALI. There was dissociation between arterial and cerebral tissue oxygenation. Cerebral oxygenation and metabolism might have possibly been impaired by a more distinctive inflammatory response in the HT group.

Background: The abdominal compartment syndrome (ACS) is a life-threatening condition and may affect any critically ill patient. Little is known about the recognition and management of the ACS in Germany., Methods: A postal questionnaire was sent to departments of surgery and anesthesia of German hospitals with more than 450 beds., Results: From the 222 eligible hospitals a total of 113 replies were received. Most respondents (95%) indicated that the ACS plays a role in their clinical practice. Measurement of intra-abdominal pressure (IAP) is not performed by 26% while it is routinely done by 30%. Intra-abdominal pressure is mostly (94%) assessed via the bladder pressure. Of the respondents 41% measure IAP only in those patients thought likely to develop ACS. Risk factors of the ACS would lead to IAP monitoring in 10-23% of cases. The majority (86%) would require signs of organ dysfunction together with exceeding the IAD threshold in order to opt for a surgical decompression. The attitude towards the critical threshold (>20 mmHg or >25 mmhg) divided respondents into two groups of similar size (39% compared to 47%, respectively)., Conclusions: German anesthesiologists and surgeons are familiar with the ACS. However, about one-quarter never measure IAP and there is a considerable variance as to which patients are at risk to develop ACS and how often IAP should be measured in these patients. This could indicate a lack of acceptance or simply a persisting need for more data concerning the avoidance and treatment of the ACS.

Background: Scientific evidence is accumulating that non-invasive ventilation (NIV) may be beneficial for different patient groups with acute respiratory insufficiency (ARI). The aim of the new S3 guidelines is to propagate evidence-based knowledge about the indications and limitations of NIV in clinical practice., Methods: A total of 28 experts from 12 German medical societies were involved in the process of development of the present guidelines. These experts systematically analyzed approximately 2,900 publications. Finally, the recommendations were discussed and approved in two consensus conferences., Results: In hypercapnic ARI, NIV reduces the length of stay and mortality during intensive care treatment [grade A recommendation (A)]. Patients with cardiopulmonary edema should be treated with continuous positive airway pressure (CPAP) or NIV (A). For immunocompromized patients with ARI, NIV reduces the mortality (A). In patients with postextubation respiratory failure and during weaning from mechanical ventilation, NIV reduces the risk of reintubation (A). For patients who decline to be ventilated invasively, NIV may be an acceptable alternative (B). Non-invasive ventilation can also successfully be used in pediatric patients with ARI caused by different reasons (C). In acute respiratory distress syndrome (ARDS) NIV cannot generally be recommended because the failure rate is relatively high., Conclusion: Non-invasive ventilation is still not as widely implemented in clinical medicine as would be expected on the basis of the scientific literature. The aim of the present guidelines is to further propagate NIV for the treatment of ARI.

Introduction: Non-invasive mechanical ventilation (NIV) has been used to treat acute respiratory failure (ARF) for approximately 20 years. This guideline addresses the indications for, and limitations of, NIV as treatment for ARF according to evidence-based criteria., Methods: A panel of experts from 12 scientific medical societies reviewed circa 2900 publications. The panel judged the clinical relevance of these studies and assessed the evidence presented in each, then held two interdisciplinary consensus conferences to formulate guideline recommendations and algorithms., Results: Whenever possible, NIV should be preferred to invasive mechanical ventilation, in order to avoid the risk of ventilator and tube-associated complications such as nosocomial pneumonia (grade of recommendation A). Particularly in patients with hypercapnic ARF, NIV reduces the rate of hospital-acquired pneumonia, the length of hospital stay and mortality in the intensive care unit and in the hospital (grade of recommendation A). NIV (or continuous positive airway pressure) is also recommended in cardiogenic pulmonary edema (grade of recommendation A), as treatment for ARF in immunocompromised patients (grade of recommendation A), to prevent postextubation failure, to facilitate weaning in patients with hypercapnic ARF (grade of recommendation A), and to improve dyspnea in palliative care (grade of recommendation C). NIV is not generally recommended in patients with hypoxic ARF because of its high failure rate of 30% to over 50% in such patients., Discussion: Although evidence indicates that NIV can be used as the treatment of first choice for several indications, it is still underutilized in the acute setting. These guidelines provide evidence-based information about the indications for, and limitations of, NIV in the treatment of ARF.

Using recruitment manoeuvres in acute lung injury remains a controversial issue because no convincing outcome data support their general use, although many physiological studies have demonstrated beneficial effects on lung compliance, end-expiratory lung volume and gas exchange. One of the reasons why physiologically meaningful observations do not translate into clear clinical benefit could be the heterogeneity of the studied patient population. In patients with consolidated lungs and only limited potential for recruitment, manoeuvres might be harmful, whereas in patients with high potential for recruitment they might be helpful. However, when those populations are mixed any signal may be lost because of counteracting effects, depending on how the patient population was mixed. We do not currently have any simple tool that may readily be applied at the bedside to assess the recruitment potential in an individual patient, which would be a sine qua non for identifying a homogeneous population in a recruitment study. Therefore, the method presented by Jacob Koefeld-Nielsen and colleagues in the previous issue of Critical Care provides us with a simple method that could be used at the bedside to assess recruitment potential before the manoeuvre is applied.

Aim: To compare a new method of non-invasive determination of cardiac output based on electrical velocimetry (EV-CO) with invasive thermodilution methods., Methods: Fifty critically ill patients were enrolled into the study. EV-CO was compared with cardiac output measured by a pulmonary artery catheter (PA-CO) in one group (n= 25) and by a femoral artery catheter (PiCCO-CO) in a second group (n= 25), by simultaneous measurements. Standard electrocardiography electrodes were used for non-invasive measurements, and EV-CO was calculated using the Bernstein-Osypka equation. The invasive measurements of PA-CO and PiCCO-CO were made by the injection of iced 0.9% saline and the recording of thermodilution curves., Results: The precision values of EV-CO, PA-CO and PiCCO-CO measurements were +/- 0.46 [95% confidence interval (95% CI), +/- 0.06], +/- 0.57 (95% CI, +/- 0.09) and +/- 0.48 l/min (95% CI, +/- 0.08 l/min), respectively. The mean differences between EV-CO and PA-CO or PiCCO-CO were -0.05 +/- 0.71 and 0.22 +/- 0.78 l/min, respectively. The lower and upper limits of agreement for the comparison of EV-CO with PA-CO were -1.47 and 1.37 l/min (95% CI, +/- 0.25 l/min), respectively. In the comparison of EV-CO and PiCCO-CO, lower and upper limits of -1.34 and 1.78 l/min (95% CI, +/- 0.27 l/min) were found. The percentage errors between EV-CO and PA-CO or PiCCO-CO were 26.5% and 26.4%, respectively., Conclusions: The values of cardiac output were statistically comparable between the groups. Therefore, electrical velocimetry is a suitable method to evaluate haemodynamic variables with clinically acceptable accuracy.

Background: In acute lung injury, ventilation avoiding tidal hyperinflation and tidal recruitment has been proposed to prevent ventilator-associated lung injury. Information about dynamic recruitment may be obtained from the characteristics of pressure-volume (PV) curves or the profile of pressure-time (Paw-t) curves., Methods: Six anesthetized pigs with lung lavage-induced acute lung injury were ventilated with lung-protective settings. We measured the effects of a standard recruitment maneuver on hysteresis area and ratio obtained from the PV curve and on the stress index obtained from the Paw-t curve and correlated this with aerated and nonaerated lung volumes as measured by multislice computed tomography., Results: Hysteresis area and ratio correlated with aerated lung volume (r = 0.886). The recruitment maneuver resulted in an increase in aerated (+12%) and a decrease (-18%) in nonaerated lung. Hysteresis area correlated with alveolar recruitment, represented by an increase in aerated lung (r = 0.886) and a decrease in nonaerated lung (r = -0.829) during tidal ventilation. The stress index was always >1 and indicated tidal hyperinflation only. Values did not change after the recruitment maneuver and did not correlate with any other lung volume., Conclusions: Parameters derived from the PV curve may help in characterizing the lung aeration of the lung and in indicating recruitment. In the presence of lung-protective ventilator settings, the stress index derived from the Paw-t curve was not able to indicate recruitment.

Objective: To test the hypothesis that ventilation with 3 mL/kg tidal volume combined with extracorporeal CO2 removal by arteriovenous interventional lung assist reduces ventilator-associated organ injury in experimental acute lung injury when compared with ventilation with 6 mL/kg tidal volume without interventional lung assist., Design: Prospective, randomized, controlled trial., Setting: A university research laboratory., Subjects: A total of 14 pigs weighing 46 +/- 4 kg (mean +/- sd)., Interventions: Acute lung injury was induced by repeated lung lavages until Pao2 was <100 mm Hg, with Fio2 of 1.0 and positive end-expiratory pressure of 5 cm H2O, for 1 hr without additional lavages. Animals were randomized to an interventional group with a tidal volume of 3 mL/kg with interventional lung assist (n = 7) or to a control group with a tidal volume of 6 mL/kg without interventional lung assist (n = 7) for 24 hrs. Organ function in vivo was determined by laboratory analyses, including calculations of pulmonary ventilation/perfusion distribution. Histologic assessment of organ injury was performed post mortem after 24 hrs., Measurements and Main Results: In both groups, gas exchange improved in the course of the study (p < .05). However, in contrast to control animals, animals with lower tidal volumes and interventional lung assist had severe ventilation/perfusion mismatch, as indicated by increased perfusion to lung areas with a low ventilation/perfusion ratio (p < .05). Other variables of organ function in vivo and results of histologic examination post mortem did not reveal any statistical difference between groups., Conclusions: Combined ventilation with lower tidal volumes and extracorporeal CO2 removal as compared with traditional low tidal volumes without extracorporeal CO2 removal is not associated with differences in organ injury. Obviously, ventilation with tidal volumes of <6 mL/kg may cause pulmonary de-recruitment when positive end-expiratory pressure is not adequately increased., ((C) 2007 Lippincott Williams & Wilkins, Inc.)

Background: Cranial hypertension coincides with a reduction in cerebral blood flow as well as in oxygen delivery and influences outcome. In this study, we monitored changes in energy-related metabolites in the porcine cortex during an increase of intracranial pressure (ICP) and to determine the level at which damage occurs., Methods: Male domestic pigs (32-40 kg) were anesthetized, mechanically ventilated, and randomly assigned to either the experimental (n = 6) or control groups (n = 5). A microdialysis probe (CMA 70) was inserted into the cortex to measure extracellular dialysate concentrations of lactate, pyruvate, glucose, glutamate, and glycerol. Every hour an increase of 10 mm Hg in ICP was preformed in the experimental group by infusion of artificial cerebrospinal fluid into the ventricular system of the brain until a maximum ICP of 50 mm Hg was reached., Results: We demonstrated a significant increase of lactate and glycerol compared with control at ICP values > or =30 mm Hg and cerebral perfusion pressure (CPP) below 50 mm Hg. The increase of ICP to > or =40 mm Hg in conjunction with a reduction in CPP below 40 mm Hg led to a significant increase in the lactate/pyruvate-ratio and glutamate, as well as a decrease of glucose in relation to control., Conclusions: Our data strongly suggest that, during a defined ICP increase, lower CPP values may be tolerable until severe damage occurs. Borderline ICP and CPP values of 30 and 40 mm Hg, respectively, could be advised.

Background: Since October 2003 new regulations for qualifications to practice medicine in Germany now require compulsory courses in anaesthesiology. Therefore, existing curricular activities had to be changed from facultative courses for a small number of interested students to compulsory activities for all students., Methods: Previous data of the department of anaesthesiology at the University Hospital Aachen (Germany) were collected and taken into consideration for the development of a new curriculum: The result was a course consisting of a tutorial with integrated "basic skill training", practical training in the operating theatre and a simulation-based session, in addition to two series of lectures. An evaluation by the students was carried out using EvaLuna as a tool for web-based on-line evaluation and faculty members had to fill out a standardized questionnaire., Results: The different parts of the curriculum received the highest scores of all courses in the undergraduate medical school curriculum. Best results were achieved by the anaesthesia-simulation session followed by the tutorial and the practical training., Conclusion: The feedback of faculty members as well as the results of students' evaluation approved the developed concept of integrating anaesthesia-relevant issues into the formal medical school curriculum. Nevertheless, the on-line evaluation system EvaLuna provided additional suggestions for future improvements in the newly created curriculum.

Acute lung injury (ALI) is of paramount importance for modern intensive care since it is one of the most frequent conditions necessitating admission to an ICU. ALI is characterised by severe life threatening hypoxemia which is based on ventilation perfusion mismatching within the lung. This is mostly resulting from atelectasis formation due to primary or secondary inflammation of lung tissue. Many studies showed that this inflammatory process is not restricted to the respiratory system but might result in non pulmonary organ failure and hemodynamic compromise as well. Mechanical ventilation is considered the hallmark treatment for ALI patients aimed to recruit lung tissue and thereby reverse hypoxemia without causing additional lung injury potentially resulting from overdistention or cycling collapse during expiration. Scientific evidence shows us that prevention of ventilator induced lung injury by protective ventilation with reduced tidal volumes is resulting in better clinical outcomes. Moreover, different technologies and adjunctive therapies have been suggested based on their pathophysiology. All these treatment options will be summarized in this article. Given the clear evidence for protective ventilation and bearing in mind that clinical application of this easy concept is still not widespread we will focus on this aspect.

Aim of the Study: There is consent that the use of automated external defibrillators (AED) by laypersons improves survival rates in case of cardiac arrest, but no evident consensus exists on the content and duration of training for this purpose. Acceptance of the implementation of Public Access Defibrillation programmes will depend on practical and target-oriented training concepts. The aim of this prospective randomised interventional study was to evaluate long-term effects of a specific, minimal training programme on using semiautomatic and fully automatic AEDs in simulated cardiac arrest., Materials and Methods: In a mock cardiac arrest scenario 59 medical students with no specific previous medical education were tested during their first semester at medical school. Students who passed any medical emergency training were excluded. The subjects were evaluated before and after attending specified instructions of 15 min duration and after a period of 6 months. Main end points were time to first shock, electrode-positioning and safety throughout the procedure., Results: Mean time to first shock without prior instructions was 77.7+/-17.05 s. After instruction there was a significant improvement to 56.5+/-9.5 s (p

Aim of the Study: External chest compression (ECC) is an essential part of cardiopulmonary resuscitation and usually performed without any adjuncts. Although different supportive devices have been developed, none have yet been implemented as a standard procedure to guide rescuers in resuscitation. This study investigates the effects of the CPREzy-pad on ECC performed by first year medical students during simulated cardiac arrest., Materials and Methods: Two hundred and two subjects were randomised and asked to perform 5 min of single-rescuer-CPR. Group 1 (n = 111) was taught classic ECC, followed by ECC with the CPREzy and was tested in ECC with the CPREzy. Group 2 (n = 91) was taught and tested in classic ECC only. One week later each group was divided: Group 1A was tested in ECC with the CPREzy again; Group 1B was tested in classic ECC. Group 2A was taught and tested in ECC with CPREzy; Group 2B was tested in classic ECC again. Primary endpoints were compression rate (90-110/min) and compression depth (40-50mm)., Results: Comparing groups 1 and 2, ECC was significantly superior with CPREzy (correct rate: 93.7% versus 19.8%, p < or = 0.01; depth: 71.2% versus 34.1%, p < or = 0.01). The group tested with CPREzy initially 1 week later (2A; n = 36) improved significantly in correct compression rate (19.8% versus 88.9%, p < or = 0.01) and compression depth (34.1% versus 75.0%, p < or = 0.02). The control-group (2B; n = 55) without CPREzy demonstrated poor performance in both evaluations (correct rate: 19.8% versus 25.5%, depth: 34.1% versus 43.6%)., Conclusion: CPREzy as a simple portable and re-usable device is able to improve performance of ECC in simulated cardiac arrest.

Background: Emergency medical service (EMS) systems in Europe have developed differently due to legal, educational and organisational aspects. The aim of the present study was to compare cardiopulmonary resuscitation (CPR) outcomes and characteristics in three differently organised and staffed EMS systems in close vicinity., Methods: We analysed the charts of patients treated in the EMS systems of the cities of Aachen (Germany), Heerlen (The Netherlands) and Eupen (Belgium), retrospectively. Main outcome measures were the rate of return of spontaneous circulation (ROSC), hospital discharge and cerebral performance after 1 year. Furthermore, factors influencing neurological outcome and the incidence of cross-border emergency assistance were assessed., Results: Of 852 patients found unresponsive with no palpable pulse and/or the absence of breathing, CPR was performed in 322 patients. The overall rate of ROSC was 44.1 and 13.7% of patients were discharged alive. A good neurological outcome was observed in 95.5% of survivors. The rate of ventricular fibrillation was significantly higher (46.9% versus 21.9 and 21.2%, p < 0.05) and the total amount of epinephrine given during CPR significantly lower (4.5+/-5.2 mg versus 9.8+/-10.8 and 8.4+/-6.2 mg, p < 0.05) in the Dutch system. No significant differences in outcome variables were observed between the systems. Neurological outcome was favourable when the arrest was witnessed, occurred in a public place, the initial rhythm was shockable, a low total amount of adrenaline (epinephrine) was given and the call-response interval was short. In 1.2% of the cases cross-border emergency care was provided., Conclusions: Despite medical and organisational discrepancies, outcomes of CPR in three neighbouring EMS systems are comparable. Neurological outcome is influenced by demographical, organisational and medical factors. Cross-border emergency assistance for CPR is almost undetectable and needs improvement.

It has been shown that global anoxia leads to dramatic changes in the diffusion properties of the extracellular space (ECS). In this study, we investigated how changes in ECS volume and geometry in the rat somatosensory cortex during and after transient hypoxia/ischemia correlate with extracellular concentrations of energy-related metabolites and glutamate. Adult male Wistar rats (n = 12) were anesthetized and subjected to hypoxia/ischemia for 30 min (ventilation with 10% oxygen and unilateral carotid artery occlusion). The ECS diffusion parameters, volume fraction and tortuosity, were determined from concentration-time profiles of tetramethylammonium applied by iontophoresis. Concentrations of lactate, glucose, pyruvate and glutamate in the extracellular fluid (ECF) were monitored by microdialysis (n = 9). During hypoxia/ischemia, the ECS volume fraction decreased from initial values of 0.19 +/- 0.03 (mean +/- S.E.M.) to 0.07 +/- 0.01 and tortuosity increased from 1.57 +/- 0.01 to 1.88 +/- 0.03. During reperfusion the volume fraction returned to control values within 20 min and then increased to 0.23 +/- 0.01, while tortuosity only returned to original values (1.53 +/- 0.06). The concentrations of lactate and glutamate, and the lactate/pyruvate ratio, substantially increased during hypoxia/ischemia, followed by continuous recovery during reperfusion. The glucose concentration decreased rapidly during hypoxia/ischemia with a subsequent return to control values within 20 min of reperfusion. We conclude that transient hypoxia/ischemia causes similar changes in ECS diffusion parameters as does global anoxia and that the time course of the reduction in ECS volume fraction correlates with the increase of extracellular concentration of glutamate. The decrease in the ECS volume fraction can therefore contribute to an increased accumulation of toxic metabolites, which may aggravate functional deficits and lead to damage of the central nervous system (CNS).

Objectives: It is not clear whether the mechanical properties of the respiratory system assessed under the dynamic condition of mechanical ventilation are equivalent to those assessed under static conditions. We hypothesized that the analyses of dynamic and static respiratory mechanics provide different information in acute respiratory failure., Design: Prospective multiple-center study., Setting: Intensive care units of eight German university hospitals., Patients: A total of 28 patients with acute lung injury and acute respiratory distress syndrome., Interventions: None., Measurements: Dynamic respiratory mechanics were determined during ongoing mechanical ventilation with an incremental positive end-expiratory pressure (PEEP) protocol with PEEP steps of 2 cm H2O every ten breaths. Static respiratory mechanics were determined using a low-flow inflation., Main Results: The dynamic compliance was lower than the static compliance. The difference between dynamic and static compliance was dependent on alveolar pressure. At an alveolar pressure of 25 cm H2O, dynamic compliance was 29.8 (17.1) mL/cm H2O and static compliance was 59.6 (39.8) mL/cm H2O (median [interquartile range], p < .05). End-inspiratory volumes during the incremental PEEP trial coincided with the static pressure-volume curve, whereas end-expiratory volumes significantly exceeded the static pressure-volume curve. The differences could be attributed to PEEP-related recruitment, accounting for 40.8% (10.3%) of the total volume gain of 1964 (1449) mL during the incremental PEEP trial. Recruited volume per PEEP step increased from 6.4 (46) mL at zero end-expiratory pressure to 145 (91) mL at a PEEP of 20 cm H2O (p < .001). Dynamic compliance decreased at low alveolar pressure while recruitment simultaneously increased. Static mechanics did not allow this differentiation. The decrease in static compliance occurred at higher alveolar pressures compared with the dynamic analysis., Conclusions: Exploiting dynamic respiratory mechanics during incremental PEEP, both compliance and recruitment can be assessed simultaneously. Based on these findings, application of dynamic respiratory mechanics as a diagnostic tool in ventilated patients should be more appropriate than using static pressure-volume curves.

A pathological increase of intraabdominal pressure (IAP) is frequently observed in severely ill patients suffering from surgical diseases. This may lead to the abdominal compartment syndrome (ACS) which is characterized by an IAP >20 mmHg (>2.67 kPa) and failure of one or more organ systems. The mortality of ACS exceeds 60%. Knowledge concerning the sequelae of ACS is abundant, however, measurement of IAP is not routinely performed even if patients present with corresponding risk factors. This is probably due to a variable incidence of ACS and scepticism regarding the results of bladder pressure measurement. However, measurement of IAP can now be performed semi-automatically, continuously and in a standardized fashion. The therapy of ACS, i.e. decompression laparotomy and laparostomy, is undisputed. Since a heterogeneous group of patients can be affected, monitoring of IAP is indicated in patients needing intensive care. A consistent registration of IAP will improve knowledge and guidelines regarding the therapy of a pathologically increased IAP. Nevertheless, patients in whom ACS is suspected should be decompressed as soon as possible.

Objective: The early phase of acute respiratory distress syndrome (ARDS) is characterized by impaired respiratory mechanics, ventilation-perfusion mismatch, and severe hypoxemia. Partial ventilatory support can effectively unload the respiratory workload and improve pulmonary gas exchange with less hemodynamic compromise. The partial ventilatory support mode most indicated in early phases of ARDS has not been determined. This study compares the effects of assisted ventilatory techniques on breathing pattern, gas exchange, hemodynamic function, and respiratory effort with those of controlled mechanical ventilation in similarly sedated subjects., Design: Prospectively randomized crossover animal study., Setting: Animal research laboratory., Subjects: Eleven anesthetized and mechanically ventilated pigs., Interventions: Acute lung injury was induced by lung lavage. Pressure-controlled ventilation (PCV), pressure-controlled assisted ventilation (P-ACV), bilevel positive airway pressure (BIPAP), and pressure support ventilation (PSV) with equal airway pressures and sedation were applied in random order., Measurements and Main Results: Gas exchange, respiratory effort, and hemodynamic function were measured, and ventilation-perfusion distributions were calculated by multiple inert-gas-elimination techniques. The results revealed that partial ventilatory support was superior to PCV in maintaining adequate oxygenation and hemodynamic function with reduced sedation. The effects of P-ACV, BIPAP, and PSV were comparable with respect to gas exchange and hemodynamic function, except for a more pronounced reduction in shunt during BIPAP. P-ACV and PSV were superior to BIPAP to reduce respiratory drive and work of breathing. PSV affected the pattern of breathing and deadspace to a greater degree than did P-ACV., Conclusions: In acute lung injury, P-ACV preserves oxygenation and hemodynamic function with less respiratory effort compared with BIPAP and reduces the need for sedation compared with PCV.

For patients with most severe acute respiratory distress syndrome (ARDS) conservative treatment with lung protective ventilation is often not sufficient to prevent life-threatening hypoxemia and additional strategies are necessary. Extracorporeal lung assist (ECLA) or extracorporeal membrane oxygenation (ECMO) using capillary membrane oxygenators can provide sufficient gas exchange and lung rest. In 2 randomized trials mortality was unchanged for ECMO. Today an technically enhanced ECMO is used for most severe ARDS using clinical algorithm and different case studies demonstrated a survival rate about 56%. Today miniaturized ECMO with optimized blood pumps and oxygenators are available and could enhance safety and clinical management. Another approach is an arterio-venous pumpless interventional lung assist (ILA) with a low resistance oxygenator. Advantages seem a simplified clinical management and less blood trauma. At present new devices are developed for chronic respiratory failure or bridge to lung transplant. Oxygenators with even less flow resistance could be implanted paracorporeal using the right ventricle as driving force. An intravascular oxygenator has been developed using the combination of a miniaturized blood pump and an oxygenator for implantation in the vena cava. Well designed clinical trials are necessary to demonstrate a clinical benefit for these experimental devices.

Although recruitment of atelectatic lung is a common aim in acute respiratory distress syndrome (ARDS), the effects of a recruitment maneuver have not been assessed quantitatively. By multislice spiral CT (MSCT), we analyzed the changes in lung volumes calculated from the changes in the CT values of hyperinflated (V(HYP)), normally (V(NORM)), poorly (V(POOR)) and nonaerated (V(NON)) lung in eight mechanically ventilated pigs with saline lavage-induced acute lung injury before and after a recruitment maneuver. This was compared to single slice analysis near the diaphragm. The increase in aerated lung was mainly for V(POOR) and the less in V(NORM). Total lung volume and intrathoracic gas increased. No differences were found for tidal volumes measured by spirometry or determined by CT. The inspiratory-expiratory volume differences were not different after the recruitment maneuver in V(NON) (from 62+/-18 ml to 43+/-26 ml, P = 0.114), and in V(NORM) (from 216+/-51 ml to 251+/-37 ml, P = 0.102). Single slice analysis significantly underestimated the increase in normally and poorly aerated lung. Quantitative analysis of lung volumes by whole lung MSCT revealed the increase of poorly aerated lung as the main mechanism of a standard recruitment maneuver. MSCT can provide additional information as compared to single slice CT.

Hirudin serves as an alternative anticoagulant for extracorporeal blood circulation. Comparing anticoagulation with hirudin (2.5 or 5.0 microg/mL) and heparin (2.0 or 4.0 IU/mL) human blood was circulated in a modified 'Chandler System' using PVC-tubes for 2 hours at 37 degrees C. Activation of coagulation (thrombin-antithrombin III-complex, prothrombin fragment 1+2 and D-Dimer), platelet (platelet factor 4 - PF4) and complement systems was analyzed. Both heparin concentrations and 5.0 microg/dL hirudin led to as significantly less activated plasmatic coagulation as 2.5 microg/dL hirudin. Decreased levels of PF4 and anaphylatoxin C5a (p<0.05) as well as terminal complement complex demonstrated improved hemocompatibility after anticoagulation with heparin in contrast to hirudin. Because initial coagulation cascade, platelet activation and complement activation is less influenced by hirudin than by heparin, hemocompatibility is more dependent on the characteristics of the biomaterials used. This predestines hirudin as anticoagulant for in vitro studies analyzing hemocompatibility of biomaterials or surface modifications.

Bleeding is still the most common complication during extracorporeal membrane oxygenation (ECMO) for temporary cardio-circulatory support. We present a case of a young man suffering from intractable hemorrhage during ECMO support, who was pre-treated with glycoprotein IIb/IIIa receptor antagonist Tirofiban due to a suspicion of myocardial ischemia. After failure of conventional hemostatic means, hemostasis was achieved by the donation of recombinant Factor VIIa (rFVIIa). Aspects of bleeding control during extracorporeal circulatory support, the use of Tirofiban and rFVIIa are discussed.

Introduction: Atelectasis is a common finding in acute lung injury, leading to increased shunt and hypoxemia. Current treatment strategies aim to recruit alveoli for gas exchange. Improvement in oxygenation is commonly used to detect recruitment, although the assumption that gas exchange parameters adequately represent the mechanical process of alveolar opening has not been proven so far. The aim of this study was to investigate whether commonly used measures of lung mechanics better detect lung tissue collapse and changes in lung aeration after a recruitment maneuver as compared to measures of gas exchange, Methods: In eight anesthetized and mechanically ventilated pigs, acute lung injury was induced by saline lavage and a recruitment maneuver was performed by inflating the lungs three times with a pressure of 45 cmH2O for 40 s with a constant positive end-expiratory pressure of 10 cmH2O. The association of gas exchange and lung mechanics parameters with the amount and the changes in aerated and nonaerated lung volumes induced by this specific recruitment maneuver was investigated by multi slice CT scan analysis of the whole lung., Results: Nonaerated lung correlated with shunt fraction (r = 0.68) and respiratory system compliance (r = 0.59). The arterial partial oxygen pressure (PaO2) and the respiratory system compliance correlated with poorly aerated lung volume (r = 0.57 and 0.72, respectively). The recruitment maneuver caused a decrease in nonaerated lung volume, an increase in normally and poorly aerated lung, but no change in the distribution of a tidal breath to differently aerated lung volumes. The fractional changes in PaO2, arterial partial carbon dioxide pressure (PaCO2) and venous admixture after the recruitment maneuver did not correlate with the changes in lung volumes. Alveolar recruitment correlated only with changes in the plateau pressure (r = 0.89), respiratory system compliance (r = 0.82) and parameters obtained from the pressure-volume curve., Conclusion: A recruitment maneuver by repeatedly hyperinflating the lungs led to an increase of poorly aerated and a decrease of nonaerated lung mainly. Changes in aerated and nonaerated lung volumes were adequately represented by respiratory compliance but not by changes in oxygenation or shunt.

Since June 2002, revised regulations in Germany allow medical faculties to implement new curricular concepts. The medical faculty of the Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Germany, decided to start a major reform experiment in winter 2003, focussing on an interdisciplinary integration of organs and organ systems such as the cardiovascular or respiratory system. Furthermore, students will have contact with patients at an early stage of their studies. Thus, re-organisation of course contents should lead to a chance to improve practical experience. With the public having the right to expect that physicians and all physicians in training possess a basic knowledge of emergency medical care and the necessary skills to manage acute problems, it was decided to start the first year of the Medical Reform Curriculum Aachen with 3 weeks interdisciplinary introduction into emergency medical care. The task consisted of defining interdisciplinary core objectives and the need to implement teaching and learning principles necessary for further education. Due to this, the content of this course should have practical relevance for the students concerning their practical experiences in the future. The result is an introductory course in emergency medical care in the first semester, coordinated with the lectures. Besides skill training on basics of emergency medical care (basic life support (BLS), early defibrillation), practical training in other lifesaving techniques (e.g., immobilisation skills) and basic principles of daily clinical care are included. In addition, personal safety and a standard algorithm for assessing the patient are covered by problem-based learning sessions. The course evaluation data clearly showed acceptance of the new approach and enhances possibilities of extending implementation of relevant topics concerning emergency medical care within the Medical Reform Curriculum Aachen.

Introduction: There is evidence that use of automated external defibrillators (AEDs) by laypersons improves rates of survival from cardiac arrest, but there is no consensus on the optimal content and duration of training for this purpose. In this study we examined the use of semiautomatic or automatic AEDs by laypersons who had received no training (intuitive use) and the effects of minimal general theoretical instructions on their performance., Methods: In a mock cardiac arrest scenario, 236 first year medical students who had not previously attended any preclinical courses were evaluated in their first study week, before and after receiving prespecified instructions (15 min) once. The primary end-point was the time to first shock for each time point; secondary end-points were correct electrode pad positioning, safety of the procedure and the subjective feelings of the students., Results: The mean time to shock for both AED types was 81.2 +/- 19.2 s (range 45-178 s). Correct pad placement was observed in 85.6% and adequate safety in 94.1%. The time to shock after instruction decreased significantly to 56.8 +/- 9.9 s (range 35-95 s; P < or = 0.01), with correct electrode placement in 92.8% and adequate safety in 97%. The students were significantly quicker at both evaluations using the semiautomatic device than with the automatic AED (first evaluation: 77.5 +/- 20.5 s versus 85.2 +/- 17 s, P < or = 0.01; second evaluation: 55 +/- 10.3 s versus 59.6 +/- 9.6 s, P < or = 0.01)., Conclusion: Untrained laypersons can use semiautomatic and automatic AEDs sufficiently quickly and without instruction. After one use and minimal instructions, improvements in practical performance were significant. All tested laypersons were able to deliver the first shock in under 1 min.

Background: Survivors of acute respiratory distress syndrome exhibit neuropsychological sequelae that might be attributable to hippocampal damage. The authors sought to determine the effects of hypoxemia in a pig model of acute lung injury on the hippocampal region and the release of S-100 protein in comparison to a control group in which hypoxemia was induced by reducing the inspired oxygen fraction., Methods: Hypoxemia was induced in 14 female pigs by repeated lung lavages (lung injury group; n = 7) or by reducing the inspired oxygen fraction (hypoxia-only group; n = 7). Hemodynamic variables, gas exchange, and serum concentrations of S-100 protein were measured at baseline, after induction of acute lung injury, and subsequently for 12 h. Animals were euthanized, and the brains were removed for histopathologic examination., Results: Comparable blood gases were seen in both groups. Serum S-100 protein concentrations were comparable for both groups at baseline. At all other time points, S-100 concentrations were significantly higher in the lung injury group. Neuropathologic examination showed basophilic and shrunken neurons of the pyramidal cell layer in the hippocampal CA1 subregion of all pigs in the lung injury group. Few abnormalities were seen in the hypoxia-only group., Conclusions: The same degree of hypoxemia induced in a lavage model of acute lung injury results in greater brain damage assessed by S-100 protein and histopathologic findings when compared to a group in which hypoxemia at the same degree was induced by reducing the inspired oxygen fraction. This suggests that acute lung injury leads to neuropathologic changes independent of hypoxemia.

Six hours after an uncomplicated extended resection of ovarian cancer, postoperative arterial bleeding led to life-threatening blood loss in a 44-yr-old Jehovah's Witness who refused blood transfusion. Haemoglobin (Hb) decreased from 2.5 g dl(-1) directly after the emergency laparotomy, followed by a 10 h immeasurable period (below detectable minimum value of the analyser), to a measurable minimum of 1.5 g dl(-1) after 20 h. Haematopoiesis was induced by high-dose i.v. erythropoietin therapy (600 IU kg(-1)) and continued on days 3, 6, 8, 10 and 13. Iron, folic acid and vitamins were given as supplements. The patient needed ventilatory assistance for 18 days and some inotropic support. Complications included increases in pancreatic enzymes and liver enzymes, jaundice and skin necrosis at the fingertips and toes. Myopathy led to transient tetraparesis. Haemoglobin rose from 1.5 to 3.4 g dl(-1) (day 10) and the patient was discharged from the intensive care unit with haemoglobin 6.5 g dl(-1) on day 24. She made a full recovery and is still free of cancer in remission.

Over the last years, several observational studies have suggested that extracorporeal lung assist (ECLA) may be an important contribution to clinical algorithms for the treatment of most severe acute respiratory distress syndrome (ARDS). Today ECLA is used only as a rescue therapy in life threatening gas exchange disorders if maximal conventional therapy fails to prevent from hypoxemia. With subsequent reduction of complications and improvement of biocompability, extracorporeal membrane oxygentation (ECMO) indications may be extendend to treat patients earlier and not only in rescue situations along the original idea to buy the lung some time to heal by avoiding further ventilator associated lung injury. Veno-venous ECMO therapy at present is an important therapeutic option in severe ARDS with persisiting life threatening gas exchange disorder as a rescue therapy. The development of smaller, less complex and more secure ECMO or pumpless veno-arterial ECLA systems has the potential to perform controlled studies of its use in ARDS and potentially expand indications.

Objective: Measurements from the pulmonary pressure-volume (PV) curve have been proposed to adjust ventilator settings. We investigated the effects of repeated construction of an inflation PV curve implemented in a standard ventilator on recruitment or derecruitment in acutely injured lungs., Design and Setting: Prospective experimental animal study in eight anesthetized and mechanically ventilated pigs., Interventions: Acute lung injury was induced by lung lavage and animals were ventilated in volume controlled mode with PEEP 10 cmH(2)O. The PV curve was constructed five times repeatedly by constant pressure rise, after which ventilation with the preset PEEP was resumed immediately. Studies of hemodynamics, lung mechanics, blood gases and computed tomography were carried out before and after maneuvers., Measurements and Results: Derecruitment was assessed as an increase in nonaerated lung volume (V(NON)), and V(PEEP) was the end-expiratory volume difference between PEEP and ZEEP. There was a significant decrease in PaO(2) from 90.4+/-33.3 to 70.9+/-36.3 mmHg and a rise in venous admixture from 47.8+/-12.7 to 59.1+/-16.6%. V(PEEP) was reduced from 244 to 202 ml. A corresponding decrease in normally aerated lung volume was observed, while regression analysis revealed increase in V(NON) depending on the amount of preexisting atelectasis., Conclusions: Repeated generation of the PV curve with a readily available tool resulted in worsened oxygenation. Derecruitment of the lungs occurred with loss of PEEP at the start of the maneuver, which could not be recovered by a maximum inflation pressure of 40 cmH(2)O. Repeated use of the investigated tool should be cautioned, and users should consider measures to preserve aerated lung volumes.

Purpose of Review: To provide some practical and clinical considerations that may guide users through the decision process when choosing mechanical ventilators, Recent Findings: Although the complexity of mechanical ventilators is steadily increasing, the importance of many devices developed over the course of the technical evolution is still a matter of discussion. Recent data demonstrate that the technical performance of equivalent ventilators (ie, machines of the same generation and category) is pretty similar, suggesting that the different manufacturers keep in step with new developments. Thus, other factors than technical limitations will probably influence the choice of ventilators. Among them the ability of the staff to understand the rationale of the different devices and controls as well as deal with the complexity of the ventilator may be particularly important., Summary: Choosing mechanical ventilators should begin by defining the algorithms of how to ventilate a patient. Once this is done, a ventilator should allow the transformation of specific strategies into practice and the adaptation of the mechanical support to the needs of the individual patient. This procedure is crucially important, because ventilator therapy should always be determined by the physician and based on solid physiologic rationales rather than by the technical features of the machine.

Iloprost, a prostacyclin analogue with a prolonged plasma half-life has beneficial effects in chronic pulmonary hypertension, whereas the effects in acute lung injury (ALI) are unknown. The present study was performed to evaluate the cardiopulmonary effects of iloprost in experimental ALI. ALI was induced in 18 pigs by repeated lung lavage. Animals were randomised to controls, i.v. or inhaled iloprost for 15 min. Haemodynamics, gas exchange and ventilation-perfusion distribution were measured at the end of iloprost application and after 1 and 2 h. As a short-term effect, both i.v. and inhaled iloprost significantly decreased pulmonary artery pressure without major effects on gas exchange or systemic haemodynamics. After 1 and 2 h, a reduction of pulmonary hypertension was no longer present. As a long-term effect, inhaled, but not i.v., iloprost decreased pulmonary shunt and significantly improved gas exchange after 1 and 2 h. In conclusion, the single application of iloprost revealed short-term pulmonary vasodilation without other major cardiopulmonary effects. However, inhaled iloprost improved gas exchange due to a decrease of pulmonary shunt as a long-term effect, possibly as a result of a reduction of lung oedema formation.

Sedation and analgesia are relevant aspects for the adequate treatment of patients in an intensive care unit. Recent drug developments and new strategies for ventilation provide improved sedation management allowing better adaptation to the clinical background and individual needs of the patient. This article provides an overview on the application of different substance groups. Focus is placed on newly developed pharmaceuticals such as dexmedetomidine. Another aspect is scoring system-related and EEG-based monitoring of depth of sedation. Modern concepts of analgesia and sedation for ICU patients have been developed based on the interaction of different parameters such as adaptive sedation and analgesia management (ASAM).

During the last years biochemical neuromonitoring with various molecules such as S-100 protein has become popular. A huge number of investigations both experimental and clinical have been undertaken to determine diagnosis and prognosis of patients with acute neurologic diseases. This article gives a review on the current knowledge, indications and limitations on the use of S-100 protein with regard to most of the acute neurological diseases an intensivist is confronted with in everyday practice.

Background: One-lung ventilation is frequently used in thoracic surgery. However, hypoxic pulmonary vasoconstriction of the atelectatic lung may produce pulmonary hypertension. The objective of the present study was to compare the acute effects of intravenous versus aerosolized prostacyclin (PGI(2)) on pulmonary and systemic circulation., Methods: PGI(2) was administered in 11 anesthetized and unilaterally ventilated pigs by infusion (5, 10, and 20 ng/kg body weight/min) and by inhalation (4, 8, and 16 ng/kg body weight/min) in a cross-over design., Results: Infusion of PGI(2) reduced both pulmonary (PVR) and systemic vascular resistance (SVR). Due to a concomitant increase in cardiac index (CI) mean arterial (MAP) and pulmonary artery pressures (MPAP) did not change significantly. In contrast, aerosolized PGI(2) produced a significant decrease in PVR (-21.4 to -32.8%) and MPAP (-12.0 to -17.8%) without affecting SVR, MAP, and CI. Arterial oxygenation tension (p(a)O(2)) was not affected., Conclusion: During one-lung ventilation only aerosolized prostacyclin produced a selective pulmonary vasodilation.

Venous thromboembolism is a common and frequent complication of hospitalized patients. Some venous thromboembolisms may be subclinical, while others present as symptomatic deep vein thrombosis and/or pulmonary embolism. Venous thromboembolism and pulmonary embolism contribute significantly to inhospital morbidity and mortality. The risk of venous thromboembolism is aggravated by dispositional and/or expositional risk factors. In patients at intermediate or high risk of venous thromboembolism, additional pharmacological thromboembolism prophylaxis becomes mandatory.

With an incidence of 130,000 per year, sudden cardiac death is one of the most frequent causes of death in Germany. Each day 350 patients die from cardiac arrest. Survival depends essentially on the time delay before professional help arrives and sufficient resuscitation measures have been started. At present, survival of sudden cardiac death is reported to be in the range of 5-8%. In preclinical conditions, many studies have already shown a successful use of automated external defibrillators (AED) by first responders even if they are lay persons. Even in large hospitals with maximum care facilities, delays before beginning resuscitation measures can occur which results in a dramatic reduction of the survival rate. Therefore, it seems reasonable to use AED in large hospitals. For implementation, training programmes and a nationally standardized documentation of resuscitation events should be promoted.

Background: Extensive knowledge and skills in the basics of emergency medical care are of paramount importance for every physician and should therefore be an integral part of medical education., Methods: Regulations for medical licensure in Germany were revised by the administrative authorities in 2002 and as a consequence the Medical Faculty of the University of Aachen (Germany) decided to start the Medical Reform Curriculum Aachen. A multidisciplinary, problem-oriented and organ-related approach to medical education replaces the classical discrimination between basic and clinical sciences., Results: With AIX-PERT (AIX-la-Chapelle Program for Emergency medical care and Resuscitation Training), a program consisting of problem-based learning sessions was developed for introduction to the first year students. Defined teaching objectives in emergency medicine are now incorporated in undergraduate medical education., Conclusion: The extremely positive evaluation of the new approach encouraged us to promote AIX-PERT further. In the future the effects of success of this approach will be assessed by longitudinal studies of skills and knowledge during the continuing curriculum.

Objective: We investigated whether improvement in ventilation perfusion (.V(A)/.Q) distribution during mechanical ventilation using biphasic positive airway pressure (BIPAP) with spontaneous breathing may be attributed to an effectively increased transpulmonary pressure (P(TP)) and can also be achieved by increasing P(TP) during controlled ventilation., Design: In 12 pigs with saline lavage-induced lung injury we compared the effects of BIPAP to pressure-controlled ventilation with equal airway pressure (PCV(AW)) or equal transpulmonary pressure (PCV(TP)) on V(A)/.Q distribution assessed by the multiple inert gas elimination technique (MIGET)., Setting: Animal laboratory study., Measurements and Results: Intrapulmonary shunt was 33+/-11% during BIPAP, 36+/-10% during PCV(AW) and 33+/-15% during PCV(TP) ( p= n.s.). BIPAP resulted in higher PaO(2) than PCV(AW) (188+/-83 versus 147+/-82 mmHg, p < 0.05), but not than PCV(TP) (187+/-139 mmHg). Oxygen delivery was significantly higher during BIPAP (530+/-109 ml/min) versus 374+/-113 ml/min during PCV(AW) and 353+/-93 ml/min during PCV(TP) ( p < 0.005). Tidal volume with PCV(TP) increased to 11.9+/-2.3 ml/kg, compared to 8.5+/-0.8 with BIPAP and 7.6+/-1.4 with PCV(AW) ( p <0.001) and cardiac output decreased to 3.5+/-0.6 l/min (BIPAP 4.9+/-0.8 and PCV(AW) 3.9+/-0.8, p<0.006)., Conclusions: In experimental lung injury, BIPAP with preserved spontaneous breathing was effective in increasing regional P(TP), since pressure-controlled ventilation with the same P(TP) resulted in similar gas exchange effects. However, PCV(TP) caused increased airway pressures and tidal volumes, whereby, with BIPAP, less depression of oxygen delivery and cardiac output were observed. BIPAP could be useful in maintaining pulmonary gas exchange and slightly improving oxygenation without interfering with circulation as strongly as PCV does.

Aim: Increasing age and co-morbidities of patients admitted for surgery impose new challenges on the anesthesiologist., Methods: Review of current literature regarding the perioperative management of patients with chronic pulmonary disease., Results: If patients are treated adequately, surgery can be safely performed under regional and general anaesthesia. Major risk factors include type of surgery, type and duration of anesthesia, general health status and smoking history, but not certain lung function parameters. Regional anesthesia remains the first choice for intra- and postoperative care, and if general anesthesia is necessary, early extubation should be achieved. Non-invasive ventilation could be a possible alternative in weaning failure., Conclusion: Assessing the functional status of patients admitted to surgery remains a difficult task, and in patients identified at risk by clinical examination additional spirometry and blood gases may be helpful. If there are signs of respiratory failure, the anaesthetist should monitor the patient closely and invasively, yet there is no reason to deny any patient a substantially beneficial operation.

Subject: Mortality rates remain high for the acute respiratory distress syndrome (ARDS) despite standardised treatment algorithms. Little is known about prognostic factors and exclusion criteria for advanced treatment including extracorporeal membrane oxygenation (ECMO)., Methods: In an observational study design a cohort of 93 patients with severe ARDS admitted to a referral centre were analysed according to ventilatory and vital parameters., Results: Overall survival rate was 70% and in patients who received ECMO treatment it was 67%. In patients exhibiting relevant co-morbidity the odds ratio for fatal outcome increased to 4.7 (95% CI: 3.3-24.9), and patients with multiple organ failure had a 7.5-fold increase (95% CI: 2.3-25.2) for risk of death. Survivors demonstrated a more pronounced improvement in oxygenation ( p<0.05) and CO(2) removal ( p<0.05) than non-survivors., Conclusions: Advanced treatment of ARDS including ECMO represents a therapeutic option if none of the currently considered contraindications are present. An improvement in gas exchange parameters, but not a defined value per se may be useful as a prognostic factor for favourable outcome.