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Biomedical subjects

H Burchardi

Publications and source records attributed to H Burchardi.

At least 19 recordsLinked to original sources
PubMed1996

Inhibition of interleukin-6 synthesis in an animal model of septic shock by anti-C5a monoclonal antibodies.

The complement activation fragment C5a was recently shown to induce interleukin (IL)-6 synthesis by peripheral blood mononuclear cells. To understand better the role of C5a in cytokine regulation in vivo, we investigated the effects of complement depletion by cobra venom factor (CVF) or of anti-C5a monoclonal antibodies (mAb) on IL-6 generation in an animal model of septic shock. Complement-depleted pigs which were subsequently challenged with Escherichia coli generated significantly (p < 0.05) less IL-6 during the 6-h observation period than complement-sufficient controls. To address specifically the role of C5a in IL-6 regulation, we produced a C5a(57-74) peptide-specific mAb (T13/9) which neutralizes the bioactivity of porcine C5a. The mAb T13/9 does not cross-react with the precursor protein C5. The pretreatment of pigs with anti-C5a mAb T13/9 prior to the induction of sepsis resulted in a decrease of over 75% in serum IL-6 bioactivity compared to control animals (p < 0.0001). These results indicate a role for C5a in the modulation of IL-6 synthesis in Gram-negative bacteremia.

Amino Acid Sequence↗
PubMed1996

[The use of a C1-inhibior concentrate for short-term preoperative prophylaxis in two patients with hereditary angioedema].

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.

Adult↗
PubMed1996

[Variation in inspiratory gas flow in pressure support ventilation. The effect on respiratory mechanics and respiratory work].

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)

Adult↗
PubMed1996

[Severe, accidental hypothermia: active rewarming with a simple extracorporeal veno-venous warming-circuit].

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.

Adult↗
PubMed1996

New strategies in mechanical ventilation for acute lung injury.

In the fluid-filled lungs of early adult respiratory distress syndrome (ARDS) the dependent parts are compressed and atelectatic; whereas, the nondependent areas remain aerated and functional. Ventilating these considerably restricted lungs carries the risk of overinflation and ventilatory-induced lung injury (baro-volutrauma). The consequences for adjusting mechanical ventilation are: 1) reducing tidal volumes in order to avoid alveolar hyperinflation and excessive alveolar pressures; 2) considering permissive hypercapnia if adequate CO2 elimination cannot be maintained; 3) keeping open the unstable alveoli by positive end-expiratory pressure (PEEP) (external or intrinsic). However, the large variations in regional lung compliance make it improbable that an optimal external PEEP level beneficial for the whole lung will be found; 4) using intrinsic PEEP in the inverse ratio ventilation (IRV) mode which varies with differences in regional ventilatory kinetics. No clinical study has yet convincingly demonstrated the benefit of IRV compared to conventional ventilation, controlled clinical long-term trials are not yet available; and 5) using superimposed spontaneous breathing which may be considerably more effective in opening up collapsed alveoli, combined with intentional intrinsic PEEP this is achieved in airway pressure release ventilation (APRV). Other new principles of mechanical ventilation, such as "proportional assist ventilation" or "tracheal gas insufflation" must still be considered as experimental.

Adult↗
PubMed1995

Effect of low-level PEEP on inspiratory work of breathing in intubated patients, both with healthy lungs and with COPD.

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.

Acute Disease↗
PubMed1995

[The determination of total protein is not a suitable diagnosis for the treatment of hypoalbuminemia in intensive care patients].

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.

Adolescent↗
PubMed1994

[Determination of intrinsic PEEP during mechanical ventilation. Validation of a new optional method of measurement provided by the EVITA mechanical ventilator].

Intrinsic positive end-expiratory pressure (PEEPi) occurring during mechanical ventilation depends on expiratory time constants, expiratory volume and expiration time as well as on external flow resistance (tubes, valves, etc.). It is not routinely determined in mechanically ventilated patients, but it is necessary to optimize respirator settings. The aim of the present study was the validation of an automated PEEPi determination method implemented in the respirator EVITA (Drägerwerke, Lübeck) in mechanically ventilated patients with acute lung failure. PATIENTS. The method was validated in ten sedated, myorelaxed patients with respiratory insufficiency of different etiologies (five with restrictive, and five with obstructive pulmonary disease). PEEPi was determined using the volume constant ventilatory mode at ZEEP or at an external PEEP of 5 as well as 10 cm H2O. METHOD. PEEPi was first determined with the automated method implemented in the EVITA (five measurements at each end-expiratory pressure level; PEEPEvita). Steady-state was attained between each measurement. These values were compared to the results obtained with end-expiratory occlusion (external, computer-controlled valve in the inspiratory limb of the circuit) at the respective pressure levels (PEEPEEO). The average of five measurements at each PEEP level with each method was defined as PEEPi for the particular ventilatory situation. Gas flow was measured at the proximal end of the endotracheal tube with a heated pneumotachometer (Fleisch no. 2, Fleisch, Lausanne, Switzerland) and a differential pressure transducer. Tracheal pressure was determined in the same position with a further differential pressure transducer (Dr. Fenyves & Gut, Basel, Switzerland). After A/D conversion, data were sampled with a frequency of 20 Hz and processing as well as for control of the occlusion valve was self-programmed. For the statistical analysis we used the Mann-Whitney U-test or Wilcoxon signed-ranks test; a P value less than 0.05 was considered significant. RESULTS. At the given respiratory setting and without PEEP patients with obstructive lung disease had a higher PEEPi (median: 6.4 cm H2O; range: 5.0-9.6 cm H2O) than those with restrictive pulmonary disease (median: 2.3 cm H2O; range: 0.8-3.0 cm H2O) (P < 0.05). Increasing external PEEP to 5 or 10 cm H2O significantly decreased the pressure difference between PEEPi and external PEEP (P < 0.05), but was unable to eliminate it completely. There was no statistically significant difference between PEEPEEO and PEEPEvita (P = 0.43; Wilcoxon signed-ranks tests). Regression analysis showed a highly significant correlation between PEEPEEO and PEEPEvita values (r = 0.985, P < 0.001; y = 1.03 x-0.18). DISCUSSION. PEEPi occurs during ventilation in patients with obstructive and restrictive lung disease. The difference between external end-expiratory pressure and PEEPi decreases with increasing external PEEP. However, PEEPi may increase with increasing external PEEP in some instances. The reason for this may be that the PEEPi determined at the proximal end of the endotracheal tube represents only a mean value of different PEEPi values of various lung regions. Increasing external PEEP only partially alters this mean value due to an effect on PEEPi values lower than external PEEP. The PEEPi values measured by the EVITA respirator compared with classical end-expiratory occlusion with an external valve were nearly identical. Unfortunately, PEEPi measurement of the EVITA can only be performed during controlled and not during assisting (PSV, BIPAP etc.) ventilation. Optimal respirator settings require a knowledge of PEEPi (i.e., adaption of external PEEP for lowering the work of breathing in COPD patients or prolongation of the expiratory phase to avoid unwanted side effects of an occult PEEPi on the circulation). Since mo

Aged↗
PubMed1994

[Fulminating E. coli sepsis in Fournier's gangrene].

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.

Adult↗
PubMed1994

A rational basis for the measurement of free phenytoin concentration in critically ill trauma patients.

Phenytoin binding to serum proteins and factors influencing protein binding were investigated in 38 critically ill trauma patients. In 24% of these patients, the free fraction of phenytoin was < or = 10%, whereas in 76%, the free phenytoin fraction was increased > 10%--up to 24%. Nonantiepileptic comedication, sex, or age had no influence on phenytoin binding in any of the 38 patients. Elevated free phenytoin fraction was found in those with hypoalbuminemia and hepatic and renal impairments. In these patients, the free phenytoin fraction should be measured routinely.

Adolescent↗
PubMed1994

Long-term effects of two different ventilatory modes on oxygenation in acute lung injury. Comparison of airway pressure release ventilation and volume-controlled inverse ratio ventilation.

A total of 18 patients with acute lung injury (ALI) were sequentially ventilated with two different modes of mechanical ventilation, each applied for a period of 24 h: (1) volume-controlled inverse ratio ventilation (VC-IRV), (2) airway pressure release ventilation (APRV). The individual sequence of both ventilatory modes was randomized. Ventilatory minute volume was adjusted for a PaCO2 of 35 to 45 mm Hg at the beginning of the study during the first ventilatory mode and then kept constant within preset limits. Hemodynamic variables were stable and similar during the 24-h periods of VC-IRV and APRV as well. Despite the lower sedation and spontaneous breathing during APRV, oxygen uptake was similar during both ventilatory modes. During the 24-h period of VC-IRV there was no relevant change of either airway pressures, alveolo-arterial O2 tension difference (AaDO2)/fraction of inspired oxygen (FIO2) or venous admixture. In contrast, peak airway pressures (Pawmax) during APRV were significantly lower (about 30%; p < 0.01), and decreased further within 24 h (p < 0.05). During APRV AaDO2/FIO2 and venous admixture improved significantly with time after more than 8 h (AaDO2/FIO2: 487 versus 414 mm Hg; p < 0.01; venous admixture: 20.6 versus 13.9%; p < 0.01; medians of onset versus end). The improvement was significantly different between both ventilatory modes (p < 0.01). We conclude that this indicates a progressive alveolar recruitment over time during ventilation with APRV.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1994

The effect of anaesthesia on renal function.

Anaesthesia and surgical stress can affect renal function and body fluid regulation indirectly as well as directly. The indirect effects, through influences on haemodynamics, sympathetic activity and humoral regulation, are more pronounced than the direct ones. Inhalational anaesthetics generally reduce glomerular filtration rate and urine output, mainly by extra-renal effects that are attenuated by pre-operative hydration. Opioids, barbiturates and benzodiazepines also reduce glomerular filtration rate and urine output. The effects of regional anaesthesia seem to be less than those of general anaesthesia and are related to changes in systemic haemodynamics. These peri-operative alterations of renal function are usually transient and clinically insignificant. Mechanical ventilation decreases urine volume and sodium excretion to an extent that depends on the increase in intrathoracic pressure, though ADH release, unloading of baroreceptors and activation of the renin-angiotensin system may also be involved. The direct effects of anaesthesia which are dose- and agent-dependent include effects on autoregulation of renal blood flow, alteration in the effect of ADH, and effects on tubular transport of sodium and organic acids. The only proven direct toxic effect of any anaesthetic agent is the fluoride-related toxicity of methoxyflurane.

Anesthesia↗
PubMed1994

Cost containment: Europe. Germany.

The German healthcare system offers a social network guaranteeing almost complete healthcare coverage to the German population (prevention, treatment, and rehabilitation). The system is supported by a multistructured network of public and private healthcare insurers. Fees for public insurance are equally paid by employers and employees. Healthcare expenditures heavily impact the salary levels of employees and, as a result, production costs of employers. About one third of all national healthcare spending goes to hospital care. In 1991, there were ICUs in half of all German hospitals; 3.2% of all hospital beds were ICU beds. As in most countries, the expansion in national healthcare costs in the last decade has become a serious problem in Germany. At total of 8.1% of the entire German gross national product is spent on health care, which has led to drastic governmental healthcare reform that began in 1993. The key points of this reform are: a) strict limitations on hospital budgets at 1992 levels including a new structure of hospital financing; b) controlled reduction of expenditures for medical drugs (which were formerly at the highest level in Europe); and c) controlled restriction of regional distribution for physicians. In a large German university hospital (1,461 beds; 91 ICU beds) expenses for intensive care medicine comprise about 12% of all hospital spending (5,356 deutsche mark/patient). More than 60% of these expenses are for personnel; 37% go toward drugs and medical materials. There are several possible starting points for cost containment in intensive care medicine in Germany: a) a task-adapted, countrywide diffusion of ICUs within the different levels of hospitals; b) a more selective provision of intensive care medicine (primary as well as secondary) to patients, depending on patient needs; c) a centralized and task-oriented admission and discharge policy; and d) cost containment in the use of drug therapy by centralized hospital purchasing and by establishing strict, rational, therapeutic principles. Some examples of the author's personal experience follow. In all German hospitals, expenses for personnel are about 60% to 70%. These expenses are fixed by official, standard wages. Cost containment by further restricting the number of personnel impairs the care provided. Improvements in organization and management may contribute to a higher degree of personal motivation for employees and, in turn, may result in higher working efficiency.

Budgets↗
PubMed1994

Artificial ventilation: some unresolved problems.

In acute respiratory failure interstitial oedema, alveolar collapse, and multiple atelectasis are the main mechanisms which lead to increased venous admixture and impaired oxygenation. Thus the lung volume available for pulmonary gas exchange is considerably reduced. Since there is strong evidence that alveolar overdistension causes lung damage ('barotrauma/volutrauma') large tidal volumes and high airway pressures in mechanical ventilation have to be strictly avoided, even allowing hypoventilation ('permissive hypercapnia'). Recruitment of the collapsed alveoli by external or intrinsic PEEP, or by changing body position, is often possible. However, alveolar recruitment takes much longer than previously assumed: instead of occurring within one respiratory cycle ('inflection point'), it seems to take hours. This slow recruitment process can be effectively supported by a deliberate use of intrinsic PEEP as with inverse ratio ventilation, either in volume or pressure controlled mode. Assisted spontaneous breathing makes ventilatory support less invasive and offers considerable advantages for many patients, but there are still some restrictions. Individual adaptation may be difficult in some patients. New principles of assistance control ('proportional assist ventilation') may improve individual adaptation. New concepts for weaning in COPD patients seem to offer better clinical strategies.

Acute Disease↗
PubMed1993

Hydrogen peroxide in expired breath condensate of patients with acute respiratory failure and with ARDS.

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.

Adolescent↗
PubMed1993

High-dose intravenous magnesium sulfate in the management of life-threatening status asthmaticus.

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.

Adult↗
PubMed1993

Intrinsic PEEP determined by static pressure-volume curves--application of a novel automated occlusion method.

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.

Adult↗