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The task of physicians is to maintain life, to protect and re-establish health as well as to alleviate suffering and to accompany the dying until death, under consideration of the self-determination rights of patients. Increasingly more and differentiated options for this are becoming available in intensive care medicine. Within the framework of professional responsibility physicians must decide which of the available treatment options are indicated. This process of decision-making is determined by answering the following question: when and under which circumstances is induction or continuation of intensive care treatment justified? In addition to the indications, the advance directive of the patient is the deciding factor. Medical indications represent a scientifically based estimation that a therapeutic measure is suitable in order to achieve a defined therapy target with a given probability. The ascertainment of the patient directive is achieved in a graded process depending on the state of consciousness of the patient. The present article offers orientation assistance to physicians for these decisions which are an individual responsibility. [ABSTRACT FROM AUTHOR]

Objective. The aim of the study was to investigate the effect of lung volume changes on end-expiratory lung impedance change (ELIC) in mechanically ventilated patients, since we hypothesized that ELIC may be a suitable parameter to monitor lung volume change at the bedside. Design. Clinical trial on patients requiring mechanical ventilation. Settings. Intensive care units of a university hospital. Patients. Ten mechanically ventilated patients were included in the study. Intervention. Patients were ventilated in volume-controlled mode with constant flow and respiratory rate. In order to induce changes in the end-expiratory lung volume (EELV), PEEP levels were increased from 0 mbar to 5 mbar, 10 mbar, and 15 mbar. At each PEEP level EELV was measured by an open-circuit nitrogen washout manoeuvre and ELIC was measured simultaneously using Electrical Impedance Tomography (EIT) with sixteen electrodes placed on the circumference of the thorax and connected with an EIT device. Cross-sectional electro-tomographic measurements of the thorax were performed at each PEEP level, and a modified Sheffield back-projection was used to reconstruct images of the lung impedance. ELIC was calculated as the average of the end-expiratory lung impedance change. Results. Increasing PEEP stepwise from 0 mbar to 15 mbar resulted in an linear increase of EELV and ELIC according to the equation: y =0.98 × –0.68, r2 =0.95. Conclusion. EIT is a simple bedside technique which enables monitor lung volume changes during ventilatory manoeuvres such as PEEP changes. [ABSTRACT FROM AUTHOR]

s Sepsis is a systemic response to severe infection in critically ill patients and is among the most frequent causes of death in intensive care medicine. Every year between 44,000 and 95,000 persons suffer from this illness in Germany. With the help of a retrospective electronic chart analysis in three adult ICUs of three university hospitals we calculated by a bottom-up approach the direct costs of these patients yielding per patient costs of 23,297 euros on average. Linking the direct costs per patient with the incidence data, the total direct costs for severe sepsis in Germany per year were estimated to range from 1,025 to 2,214 million euros. Direct costs, however, were found to make up only about 28% of the burden of disease of severe sepsis. The indirect costs range between 2,622 and 5,660 million euros. Productivity loss due to premature death does account for the largest part of the indirect costs. In conclusion, severe sepsis imposes annual costs between 3,647 and 7,874 million euros to the German society. [ABSTRACT FROM AUTHOR]

Objective. To define the different types of costs incurred in the care of critically ill patients and to describe some of the most commonly used methods for measuring and allocating these costs. Design. Literature review. Definitions for opportunity, direct and indirect, fixed, variable, marginal, and total costs are described and interpreted in the context of the critical care setting. Two main methods of costing are described: the 'top-down' and 'bottom-up' methods together with a number of cost proxies, such as the use of weighted hospital days, diagnosis-related groups, severity and activity scores, and effective costs per survivor. Conclusions. The assessment and allocation of costs to critically ill patients is complex and as a result of the different definitions and methods used, meaningful comparisons between studies are plagued with difficulty. When undertaking a study looking to measure costs, it is important to state: (a) the aim of the cost assessment study; (b) the perspective (point of view); (c) the type of costs that need to be measured; and (d) the time span of assessment. By being explicit about the rationale of the study and the methods used, it is hoped that the results of economic evaluations will be better understood, and hence implemented within the critical care setting. [ABSTRACT FROM AUTHOR]

Copyright of Anaesthesist is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Five commercially available oesophageal balloon catheters (OBCs) were tested to evaluate the accuracy in transmitting fast-changing pressure signals which can be observed, for example, during phrenic nerve stimulation.Setting: Research laboratory of a university hospital.Method: The OBCs tested varied in length (900-1390 mm) and inner diameter (0.9-1.5 mm) as well as in balloon material [latex or polyvinylchloride (PVC)]. A 180-cm tube served as a control. A sudden pressure drop was generated by the explosion of a pressurized latex balloon. The time between the pressure drop and 75, 50, 25 and 10% of the maximal pressure was measured.Results: The time intervals required to transduce a pressure drop of 90% varied between the different OBCs from 85 to 476 ms (control 32 ms). Transmission time was lower in OBCs with a larger inner diameter. Shortening the OBCs resulted in a further decrease in transmission time.Conclusion: The type of OBC used has an impact on signal processing. An OBCs with a short transmission time should be chosen, especially if fast pressure changes are to be evaluated such as during phrenic nerve stimulation. [ABSTRACT FROM AUTHOR]

Copyright of Intensivmedizin und Notfallmedizin is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Intensivmedizin und Notfallmedizin is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Intensivmedizin und Notfallmedizin is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To investigate the breathing pattern and the inspiratory work of breathing (WOBI) in patients with chronic obstructive pulmonary disease (COPD) assisted with proportional assist ventilation (PAV) and conventional pressure support ventilation (PSV). Design: Prospective controlled study. Setting: Intensive care unit of a university hospital. Patients: Thirteen COPD patients being weaned from mechanical ventilation. Interventions: All patients were breathing PSV and two different levels of PAV. Measurements and main results: During PAV (EVITA 2 prototype, Dräger, Germany), the resistance of the endotracheal tube (Ret) was completely compensated while the patients' resistive and elastic loads were compensated for by approximately 80 % and 50 % (PAV80 and PAV50), respectively. PSV was adjusted to match the same mean inspiratory pressure (Pinspmean) as during PAV80. Airway pressure, esophageal pressure and gas flow were measured over a period of 5 min during each mode. Neuromuscular drive (P0.1) was determined by inspiratory occlusions. Mean tidal volume (VT) was not significantly different between the modes. However, the coefficient of variation of VT was 10 ± 4.%, 20 ± 13 % and 15 ± 8 % during PSV, PAV80 and PAV50, respectively. Respiratory rate (RR) and minute ventilation (VE) were significantly lower during PAV80 as compared with both other modes, but the differences did not exceed 10 %. PAV80 and PSV had comparable effects on WOBI and P0.1, whereas WOBI and P0.1 increased during PAV50 compared with both other modes. Conclusion: Mean values of breathing pattern did not differ by a large amount between the investigated modes. However, the higher variability of VT during PAV indicates an increased ability of the patients to control VT in response to alterations in respiratory demand. A reduction in assist during PAV50 resulted in an increase in WOB and indices of patient effort. [ABSTRACT FROM AUTHOR]

Objective: To study a rewarming strategy for patients with severe accidental hypothermia using a simple veno-venous bypass in combination with a convective air warmer.Setting: Eighteen beds in a university hospital intensive care unit.Patients: Four adults admitted with a core temperature less than 30 degrees C. Hypothermia was caused by alcoholic intoxication in three patients and by drug overdose in one patient.Measurements and Main Results: All patients were rewarmed by a venovenous bypass and in three cases a convective air warmer was also used. At a bypass flow rate of 100-300 ml/min the mean increase in core temperature was 1.15 degrees C/h (Range: 1.1-1.2 degrees C/h). One patient died 2 days after rewarming as a consequence of a reactivated pancreatitis. The other three patients survived without neurological sequelae.Conclusion: This rewarming technique seems safe and effective and allowed the controlled rewarming of our patients who suffered from severe accidental hypothermia [ABSTRACT FROM AUTHOR]

Copyright of Langenbecks Archiv fuer Chirurgie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Unlabelled: During pressure support ventilation (PSV), the timing of the breathing cycle is mainly controlled by the patient. Therefore, the delivered flow pattern during PSV might be better synchronised with the patient's demands than during volume-assisted ventilation. In several modern ventilators, inspiration is terminated when the inspiratory flow decreases to 25% of the initial peak value. However, this timing algorithm might cause premature inspiration termination if the initial peak flow is high. This could result not only in an increased risk of dyssynchronization between the patient and the ventilator, but also in reduced ventilatory support. On the other hand, a decreased peak flow might inappropriately increase the patient's inspiratory effort. The aim of our study was to evaluate the influence of the variation of the initial peak-flow rate during PSV on respiratory pattern and mechanical work of breathing.Patients: Six patients with chronic obstructive pulmonary disease (COPD) and six patients with no or minor nonobstructive lung pathology (control) were studied during PSV with different inspiratory flow rates by variations of the pressurisation time (Evita I, Drägerwerke, Lübeck, Germany). During the study period all patients were in stable circulatory conditions and in the weaning phase.Method: Patients were studied in a 45 degrees semirecumbent position. Using the medium pressurization time (l s) during PSV the inspiratory pressure was individually adjusted to obtain a tidal volume of about 8 ml/kg body weight. Thereafter, measurements were performed during five pressurization times (< 0.1, 0.5, 1, 1.5, 2 s defined as T 0.1, T 0.5, T 1, T 1.5 and T 2) in random order, while maintaining the pressure support setting at the ventilator. Between each measurement steady-state was attained. Positive end-exspiratory pressure (PEEP) and FIO2 were maintained at prestudy levels and remained constant during the study period. Informed consent was obtained from each patient or his next of kin. The study protocol was approved by the ethics committee of our medical faculty. Gas flow was measured at the proximal end of the endotracheal tube with a pneumotachometer (Fleisch no. 2, Fleisch, Lausanne, Switzerland) and a differential pressure transducer. Tracheal pressure (Paw) was determined in the same position with a second differential pressure transducer (Dr. Fenyves & Gut, Basel, Switzerland). Esophageal pressure (Pes) was obtained by a nasogastric balloon-catheter (Mallinckrodt, Argyle, NY, USA) connected to a further differential pressure transducer of the same type as described above. The balloon was positioned 2-3 cm above the dome of the diaphragm. The correct balloon position was verified by an occlusion test as described elsewhere. The data were sampled after A/D conversion with a frequency of 20 Hz and processed on an IBM-compatible PC. Software for data collection and processing was self-programmed using a commercially available software program (Asyst 4.0, Asyst Software Technologies, Rochester, NY, USA). Patient's inspiratory work of breathing Wpi (mJ/l) was calculated from Pes/ volume plots according to the modified Campbell's diagram. Dynamic intrinsic PEEP (PEEPidyn) was obtained from esophageal pressure tracings relative to airway pressure as the deflection in Pes before the initiation of inspiratory flow Patient's additive work of breathing (Wadd) against ventilator system resistance was calculated directly from Paw/V tracings when Paw was lower than the pressure on the compliance curve. Two-way analysis of variance (ANOVA) was used for statistical analysis, followed by post hoc testing of the least significant difference between means for multiple comparisons. Probability values less than 0.05 were considered as significant.Results: COPD patients had significantly higher pressure support than control patients. With decreasing inspiratory flow, Wpi increased significantly in COPD patients.(ABSTRACT TRUNCATED) [ABSTRACT FROM AUTHOR]

We report the case of a 35-year-old male who was admitted to the intensive care unit because of somnolence due to accidental hypothermia. Initial examination showed a Glasgow coma score of 10 and a rectal temperature of 27.4 degrees C. Because of stable circulatory conditions, there was no mandatory indication for rewarming by means of cardiopulmonary bypass. We rewarmed the patient with an extracorporeal veno-venous haemofiltration device combined with a countercurrent fluid warmer. An average increase in body temperature of 1.34 degrees Ch-1 could be obtained. We conclude that the described technique represents an effective and well-controllable method for treatment of hypothermia in patients with stable haemodynamic conditions. Because of the availability of the required equipment, this method can also be practised in hospitals without cardiac surgical departments and cardiopulmonary bypass facilities. [ABSTRACT FROM AUTHOR]

A commercially available C1 inhibitor (C1-INH) concentrate was used for short-term prophylaxis before surgery in two patients with hereditary angioneurotic oedema. The patients suffered from recurrent subcutaneous and submucosal oedema of the face, extremities, and gastrointestinal tract as the result of a hereditary C1-INH deficiency. Both patients were receiving tranexamic acid or danazol therapy as oral long-term prophylaxis. Over the years the patients underwent several operations in regional and general anaesthesia, with mask ventilation or intubation. The C1-INH plasma concentrations measured preoperatively were always very low (0.02-0.06 g/l, normal range 0.15-0.35 g/l), despite the oral long-term prophylaxis. Substitution treatment with 500-1000 U C1-INH was performed 1 h before surgery. No side effects were seen following the concentrate infusions. With this substitution treatment no specific symptoms of hereditary angioneurotic oedema were recognized in either case. The measurement of C1-INH plasma concentration 2 h or 4 h after C1-INH substitution showed a marked rise in both patients, though normal values were not reached in either. We suggest that infusion of C1 concentrate is an appropriate form of preoperative substitution treatment in patients with hereditary angioneurotic oedema, in view of the lower risk of infection than with infusion of fresh-frozen plasma and the observed effectiveness. [ABSTRACT FROM AUTHOR]

In clinical practice, the administration of supplementary albumin often depends on the measured plasma concentration of total protein (TPC). A TPC of less than 5 g/dl is generally accepted as an indication for albumin therapy, assuming an albumin concentration of less than 2.5 g/dl. However, a physiological relation between TPC and albumin cannot be expected in critically ill patients, and thus, measurement of TPC may be misleading as an indicator for the use of albumin. Therefore, we investigated the sensitivity and specificity of TPC testing for diagnosing hypoalbuminaemia requiring treatment. METHODS. In this prospective study, 210 consecutive patients were included. Protein electrophoresis was performed three times a week; the second electrophoresis was selected for evaluation. Applied statistical analysis revealed the number of positive total protein tests indicating hypoalbuminaemia requiring treatment (sensitivity) and the number of negative with tolerable reduced albumin concentrations (specificity). RESULTS. Of the investigated patients, 27.6% had normal TPCs between 6.2 and 8.0 g/dl. In 81.9% of cases an albumin concentration below 3.5 g/dl was found, while 43 patients had a concentration below 2.5 g/dl. The sensitivity and specificity of TPC measurement for the diagnosis of clinically relevant hypoalbuminaemia (albumin concentration < 2.5 g/dl) was calculated at different cutoff points for total protein. With a TPC of 6.0 g/dl, the sensitivity was 0.96 and the specificity 0.44. With a cutoff point of 5.0 g/dl, the sensitivity was reduced to 0.65 and specificity increased to 0.86. Finally, with a TPC of 4.0 g/dl sensitivity was 0.25 and specificity almost 1. CONCLUSIONS. Depending on the cutoff point for TPC, a relevant albumin requirement would frequently not be detected. In other cases, a need for albumin would be assumed from a reduced TPC even though the albumin concentration still exceeded 2.5 g/dl. Therefore, determination of TPC is not a suitable indicator of the need for albumin replacement. As a result, we suggest routine determination of albumin concentrations instead of TPC. [ABSTRACT FROM AUTHOR]

Fournier's gangrene is a necrotising soft-tissue infection of the scrotum and perineal region caused by gram-negative and gram-positive Enterobacteriaceae. The disease is characterised by its unique appearance, its speed of onset, and its high mortality. CASE REPORT. A 26-year-old male presented to the emergency room complaining of a painful, tremendously swollen scrotum and penis (Fig. 1) that had developed within the past 24 h. Later, slurred speech, pallor, and hypotension were recognised, leading to the patient's admission to the intensive care unit. Suspecting a severe internal haemorrhage, vigorous volume therapy was started using crystalloids and colloids until blood and fresh frozen plasma were available. One hour later, septic shock was presumed and therapy augmented by IV antibiotics, tracheal intubation, and mechanical ventilation. Despite all efforts, the patients condition deteriorated rapidly and he died a few hours later due to multiple organ failure in septic shock. Postmortem, a perforated external hemorrhoidal node was found to be the primary focus of sepsis. Microbiologic cultures revealed Escherichia coli in blood and tissue samples. DISCUSSION. Fournier's gangrene is a rare disease; nevertheless, its clinical picture has to be recognised immediately in order to provide appropriate treatment in time. It occurs predominantly in males after minor trauma, colorectal or urological disease, and perineal or abdominal surgery. Fournier's gangrene usually begins with itching and pain in the scrotal region followed by swelling and dark-blueish discolouration of the scrotum and penis, occasionally including the lower abdominal wall. Fever and chills are usually present. The illness progresses to severe prostation and septic shock with a mortality of 20%-50%. Tissue cultures mostly reveal E. coli, gram-positive enterococci, Pseudomonas, Proteus, and various anaerobes. The treatment should include immediate radical surgical debridement, i.v. administration of broad-spectrum antibiotics, and cardiopulmonary support. CONCLUSION. The dramatic course of Fournier's gangrene requires early recognition, extensive surgical debridement, as well as intensive care treatment in order to prevent irreversible septic shock. [ABSTRACT FROM AUTHOR]

Objective: Validation of an open-circuit multibreath nitrogen washout technique (MBNW) for measurement of functional residual capacity (FRC). The accuracy of FRC measurement with and without continuous viscosity correction of mass spectrometer delay time (TD) relative to gas flow signal and the influence of baseline FIO2 was investigated. Design: Laboratory study and measurements in mechanically ventilated patients. Setting: Experimental laboratory and anesthesiological intensive care unit of a university hospital. Patients: 16 postoperative patients with normal pulmonary function (NORM), 8 patients with acute lung injury (ALI) and 6 patients with chronic obstructive pulmonary disease (COPD) were included. Interventions: Change of FIO2 from baseline to 1.0. Measurements and main results: FRC was determined by MBNW using continuous viscosity correction of TD (TDdyn), a constant TD based on the viscosity of a calibration gas mixture (TD0) and a constant TD referring to the mean viscosity between onset and end of MBNW (TDmean). Using TDdyn, the mean deviation between 15 measurements of three different lung model FRCs (FRCmeasured) and absolute volumes (FRCmodel) was 0.2 %. For baseline FIO2 ranging from 0.21 to 0.8, the mean deviation between FRCmeasured and FRCmodel was −0.8 %. However, depending on baseline FIO2, the calculation of FRC using TDmean and TD0 increased the mean deviation between FRCmeasured and FRCmodel to 2–4 % and 8–12 %, respectively. In patients ( n = 30) the average repeatability coefficient was 6.0 %. FRC determinations with TDmean and TD0 were 0.8–13.3 % and 4.2–23.9 % (median 2.7 % and 8.7 %) smaller than those calculated with TDdyn. Conclusion: A dynamic viscosity correction of TD improves the accuracy of FRC determinations by MBNW considerably, when gas concentrations are measured in a sidestream. If dynamic TD correction cannot be performed, the use of constant TDmean might be suitable. However, in patient measurements this can cause an FRC underestimation of up to 13 %. [ABSTRACT FROM AUTHOR]

Objective: To describe current arrangements for postgraduate training and speciality status for intensive care medicine in Europe, and to compare these with three other geographical regions: the Middle East, North America, and Australia and New Zealand.Methods: An iterative survey, by questionnaire and direct discussion, of council members of the European Society of Intensive Care Medicine, national specialist societies with involvement in intensive care, and national experts, representing four geographical regions and 47 countries.Results: For the purposes of analysis, countries with common training structures have been grouped together; the denominator therefore includes both countries and regions. Formal training programmes in intensive care medicine (ICM) are available in 18 (85%) of the 21 countries or regions surveyed. Twelve (57%) offer multidisciplinary access to intensive care training with a common core curriculum. In six (28%) training in ICM is available solely through anaesthesia. The duration of intensive care training required for recognition as a specialist in the 18 countries or regions with a formal programme ranges from 18 to 30 months, with a median of 24 months. All countries assess competence in intensive care, but methods for doing so vary widely. Eighteen countries or regions offer specialist registration (accreditation) in ICM; in 12 this is provided as dual accreditation in a base speciality and in ICM.Conclusions: There is substantial support for multidisciplinary training in ICM, as demonstrated by collaborative interspeciality developments in many countries. We propose that these national developments should be strengthened within Europe by the recognition of 'supra-speciality' status for ICM by the European Commission, and by the establishment of a multidisciplinary Board for training in ICM, with international agreement on core competencies and duration of training programmes, and a common approach to the assessment of competence through formal examination. [ABSTRACT FROM AUTHOR]

Objective: The evaluation of incidences and relating factors of severe persisting critical illness polyneuropathy (CIP) in survivors of multiple organ failure (MOF).Design: Prospective study with an entry period of 24 months. Electrophysiological studies for the diagnosis of CIP were performed 1 or 2 days before the patients were discharged from the intensive care unit (ICU). Factors which might have been related to the development of CIP were identified by a retrospective chart analysis.Setting: The interdisciplinary ICU of a university hospital.Patients: Thirty-three patients who survived MOF. Sixteen of these critically ill patients developed severe sepsis due to nosocomial infections with gram-negative bacteria.Results: In seven survivors of MOF and sepsis typical electrophysiological features of CIP, like spontaneous fibrillations and low compound muscle action potentials, were detectable at the time of discharge from the ICU. Seventeen patients with MOF following multiple trauma who developed no sepsis, and nine survivors of MOF with sepsis showed no signs of persisting CIP at the end of their ICU stay. Chart analysis revealed that eight survivors of MOF with sepsis and without the development of CIP had been treated with intravenous immunoglobulin (IVIG) with a dosage of 0.3 g/kg per day for 3 days immediately (within 24 h) after the diagnosis of sepsis. Four out of seven patients with MOF and sepsis who developed CIP were transferred to our ICU after the onset of sepsis and had not received IVIG treatment. The IVIG treatment in three patients was delayed for more than 24 h after the diagnosis of sepsis and was then omitted. Obviously not related to the development of CIP were aminoglycoside antibiotics, steroids, nutritional disturbances and episodes of hypotension or hypoxia. Neuromuscular blocking agents were not used during intensive care treatment.Conclusions: A high incidence of severe CIP persisting until the day of discharge from the ICU was related to gram-negative sepsis but not to MOF alone. Retrospective chart analysis suggested that early application of IVIG may prevent or mitigate this severe complication. However, these results have to be confirmed in a prospective, placebo-controlled study. [ABSTRACT FROM AUTHOR]

Objective: Evaluation of low-level PEEP (5 cm H2O) and the two different CPAP trigger modes in the Bennett 7200a ventilator (demand-valve and flow-by trigger modes) on inspiratory work of breathing (Wi) during the weaning phase.Design: Prospective controlled study.Setting: The intensive care unit of a university hospital.Patients: Six intubated patients with normal lung function (NL), ventilated because of non-pulmonary trauma or post-operative stay in the ICU, and six patients recovering from acute respiratory failure due to exacerbation of chronic obstructive pulmonary disease (COPD), breathing either FB-CPAP or DV-CPAP with the Bennett 7200a ventilator.Interventions: The patients studied were breathing with zero end-expiratory pressure (ZEEP), as well as CPAP of 5 cm H2O (PEEP), with the following respiratory modes: the demand-valve trigger mode, pressure support of 5 cm H2O, and the flow-by trigger mode (base flow of 20 l/min and flow trigger of 2 l/min). Furthermore, Wi during T-piece breathing was evaluated.Measurements and Results: Wi was determined using a modified Campbell's diagram. Total inspiratory work (Wi), work against flow-resistive resistance (W(ires)), work against elastic resistance (Wiel), work imposed by the ventilator system (W(imp)), dynamic intrinsic positive end-expiratory pressure (PEEPidyn), airway pressure decrease during beginning inspiration (P(aw)) and spirometric parameters were measured. In the NL group, only minor, clinically irrelevant changes in the measured variables were detected. In the COPD group, in contrast, PEEP reduced Wi and its components W(ires) and Wiel significantly compared to the corresponding ZEEP settings. This was due mainly to a significant decrease in PEEPidyn when external PEEP was applied. Flow-by imposed less Wi on the COPD patients during PEEP than did demand-valve CPAP. Differences in W(imp) between the flow-by and demand-valve trigger models were significant for both groups. However, in relation to Wi these differences were small.Conclusion: We conclude that the application of low-level external PEEP benefits COPD patients because it reduces inspiratory work, mainly by lowering the inspiratory threshold represented by PEEPidyn. Differences between the trigger modes of the ventilator used in this study were small and can be compensated for by the application of a small amount of pressure support. [ABSTRACT FROM AUTHOR]

Considerable time and energy has been invested in the conception, modelling and evaluation of sophisticated severity scoring systems for ICU patients. These systems are created to enhance the precise estimation of hospital mortality for large ICU patient populations. Their current low sensitivity precludes their use for predicting out-come for individual ICU patients. However, severity scores can already be valuable for predicting mortality in groups of general ICU patients, and are very useful in the clinical trial setting. Outcome of ICU therapy, however, should incorporate more than mortality. Morbidity, disability and quality of life should also be taken into account; these factors were not taken into consideration in the design of the currently available severity scoring systems. At present, the severity scores have a very limited or no role in clinical decision-making for an individual patient, because they are based on a number of physiological and disease-oriented variables collected during the first 24 h after ICU admission. Future developments and subsequent validation of the dynamic process of clinical, physiological and organ-specific variables could improve the sensitivity and the value of severity scoring. Further collaborative developmental work in this field should be encouraged and supported across Europe and North America. [ABSTRACT FROM AUTHOR]

In severe status asthmaticus basic medical treatment often fails to improve the patient's condition. Mechanical ventilation in this situation is associated with a high incidence of serious complications. After the bronchodilating effect of moderate-dose magnesium sulfate in asthmatic patients had been demonstrated in previous studies we treated five mechanically ventilated patients with refractory status asthmaticus successfully with high dosages of MgSO4 IV (10-20 g within 1 h depending on the bronchodilating effect). MgSO4 resulted in a significant decrease of peak airway pressure (43.0 +/- 6.8 to 32.0 +/- 8.0 cmH2O) and inspiratory flow resistance (22.7 +/- 7.0 to 11.9 +/- 6.0 cmH2O.l-1.s-1) within 1 h. The resulting serum magnesium levels after one hour were up to threefold of the normal serum levels. Although a maintainance dose of 0.4 g/h had been administered continuously during the following 24 h serum magnesium decreased towards normal values within this time. The only relevant side-effect was a mild to moderate arterial hypotension in two of the five patients during the high dose administration period of MgSO4 which responded readily to dopamine treatment. [ABSTRACT FROM AUTHOR]

Objective: Evaluation of new computer-controlled occlusion procedure for determination of intrinsic PEEP in mechanically ventilated patients and comparison with the standard end-expiratory occlusion method.Design: Prospective controlled study.Setting: Intensive care unit of a university hospital.Patients: 16 patients with acute respiratory failure of different degree and etiology. All patients were mechanically ventilated, heavily sedated and muscle paralyzed (non-depolarising relaxants). The type of ventilator, the inspiration/expiration ratio, FIO2 and PEEP were selected by the attending clinicians according to the patients' need and independently from the study.Interventions: Static compliance of the respiratory system (Cstat) was determined at varying external end-expiratory pressure settings: ZEEP (= ambient pressure), PEEP of 5 cmH2O and 10 cmH2O. All other ventilator settings were kept constant during the entire procedure.Measurements and Results: A computer-controlled occlusion method (SCASS) was used for determination of Cstat. Intrinsic PEEP was determined by SCASS as the extrapolated zero-volume intercept of the regression line of multiple pressure/volume data pairs (PEEPSCASSinspir and PEEPSCASSexpir). Directly thereafter intrinsic PEEP in this particular ventilatory setting was determined by end-expiratory occlusions (PEPPEEO). The intrinsic PEEP values of the different methods were nearly identical with a significant correlation (p < 0.0001). Mean values +/- SD: PEEPSCASSinspir 7.1 +/- 4.3 cmH2O; PEEPSCASSexpir 7.1 +/- 4.5 cmH2O; PEEPEEO 7.1 +/- 4.2 cmH2O.Conclusion: Since no significant difference between PEEPi values measured by the inspiratory and expiratory occlusion method (SCASS) was seen, this indicates that no alveolar recruitment occurred during the respiratory cycle. This study demonstrates that the automated occlusion method for measuring Cstat system can also be used with high accuracy for determination of intrinsic PEEP in mechanically ventilated patients. [ABSTRACT FROM AUTHOR]

Objective: Measurement of hydrogen peroxide concentrations in breath condensate of mechanically ventilated patients with ARDS and with risk factors for developing ARDS.Design: Open study in intensive care patients.Setting: Intensive care units of the Clinics of the University of Göttingen, a primary care center.Patients: 10 post-operatively ventilated patients as a control group and 26 patients with acute respiratory failure, 7 of them with ARDS, 12 with polytrauma, 4 with pneumonia, 3 with cardiogenic or nephrogenic pulmonary edema.Interventions: None.Measurements: Breath condensate was collected by a special cold trap and was analysed for H2O2 by a chemiluminescence method. Daily measurements were performed for 4.2 +/- 2.6 days (mean +/- SD) as soon as possible after manifestation of respiratory failure.Results: Patients with acute respiratory failure exhibited higher H2O2 concentrations than control patients (median 95 nmol/l, range 76-144 nmol/l), with the highest median value found in the ARDS group (552 nmol/l, range 154-893). After clinical improvement, H2O2 concentrations decreased to the range of the control group.Conclusion: Since high concentrations of H2O2 in breath condensate were only found in patients with ARDS or with risk factors for ARDS, the results add to the existing evidence that reactive oxygen species are associated with some acute lung diseases. [ABSTRACT FROM AUTHOR]

A new method for determination the static compliance of the respiratory system is described ("static compliance by automated single steps"--SCASS). In 12 ventilated patients pressure/volume (P/V) curves were determined by automated repetitive occlusion (6 s) at single volume steps and compared to the conventional syringe method (SM). All measurements were corrected for effects of temperature, humidity and pressure (THP). SM was found to be significantly influenced by intrapulmonary gas exchange causing an effective mean volume deficit of 217.4 +/- 65.7 ml (BTPS) at the end of the deflation. In contrast to that, the short duration of occlusion in SCASS minimize the gas exchange effects. The methodical differences between both methods result in overestimation of the inflation compliance in the uncorrected SM (SMuncorr: 83.4 +/- 12.6; SCASS: 76.0 +/- 11.9 ml/cmH2O. p less than 0.01) and underestimation of the deflation compliance resp. (SMuncorr: 58.3 +/- 7.5; SCASS: 79.1 +/- 15.0 ml/cmH2O. p less than 0.005). In contrast to the P/V curves by SM no significant hysteresis was found by SCASS. Gas exchange seems to be the main reason for the hysteresis. Even after correcting gas exchange and THP effects a significant hysteresis remained. The SCASS method avoids these problems and allows furthermore an accurate checking of leaks. [ABSTRACT FROM AUTHOR]

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