Biomedical subjects
J Briegel
Publications and source records attributed to J Briegel.
Acute respiratory distress syndrome.
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Risk factors for systemic fungal infections in liver transplant recipients.
The risk factors for systemic fungal infections were analysed retrospectively in 186 orthotopic liver transplant procedures performed in 152 patients between June 1985 and January 1993. The total incidence of systemic fungal infections was 16.5% (25/152). The incidence of disseminated candidiasis, aspergillosis, and combined candidiasis and aspergillosis was 6.5% (n = 10), 7.2% (n = 11) and 2.6% (n = 4), respectively. Mortality associated with systemic fungal infections was 80% (20 of 25 patients). There were ten cases of disseminated candidiasis, with 4 patients surviving, and 11 cases of invasive aspergillosis, with 1 patient surviving. All patients with combined systemic fungal infection died. To identify perioperative risk factors, 39 variables were used to compare patients with systemic fungal infections versus those without fungal infections. Fourteen variables were significantly associated with systemic fungal infections by univariate analysis. A consecutive logistic regression analysis revealed that the amount of fresh frozen plasma transfused due to poor initial function of the allograft and acute renal failure requiring hemofiltration were independently significant risk factors for systemic fungal infections. There was no statistical correlation between systemic fungal infections and the underlying liver disease, previous long-term corticosteroids and the postoperative immunosuppressive therapy. Risk factors identified in this study should be considered in the postoperative care of the individual liver transplant recipient. In our study a poor initial function of the hepatic allograft substantially increased the risk of systemic fungal infection.
[Continuous measurement of cardiac output with pulse contour analysis].
Pulse contour cardiac output (PCCO) is an easily applicable method for continuous measurement of cardiac output in critically ill patients. Calculation of stroke volume is possible by analysing the area under the systolic part of the arterial pulse pressure waveform together with an individual calibration factor (Zao) to account for the individually variable vascular impedance. Since vascular impedance is potentially affected by altered vascular tone, it was the aim of the present study to examine the validity of PCCO in ICU patients receiving various dosages of a variety of vasoactive drugs. PATIENTS AND METHODS. Continuous cardiac output was measured in 20 ICU patients for a total of 110 h using the pulse contour method. The precision of PCCO was determined in comparison with its calibration reference, the thermodilution method (TDCO): (1) during administration of vasoactive drugs at a constant rate and (2) during conditions with altered vascular tone and haemodynamics elicited by changes in vasoactive drug dosage. For this purpose, the patients received varying dosages of vasoactive drugs (dopamine, dobutamine, epinephrine, norepinephrine, nitroglycerin, prostacyclin and urapidil). RESULTS. A total of 165 data sets was obtained, each consisting of the average of four capnometrically triggered TDCO measurements and the corresponding PCCO values. The relative difference between methods (+/- 2 SD) was +/- 23.9% (SD 0.85 l.min-1; r = 0.93) if a single calibration at the beginning of measurement series was performed (Fig. 2). The bias of the mean cardiac output values of both methods was -0.09 l.min-1. The precision of PCCO improved to +/- 15.7% by additional calibrations (SD 0.56.min-1; r = 0.96; bias 0.003 l.min-1). Data of two patients showed that recalibration may be necessary after extreme haemodynamic changes due to septic shock or cooling. Alteration of vascular tone by clinically used dosage of vasoactive drugs, however, had no destabilizing effect on the pulse contour method. CONCLUSIONS. It could be demonstrated that PCCO provides a valuable method for continuous cardiac output measurement in the intensive care setting with a precision comparable to that of thermodilution.
Evaluation of a new continuous thermodilution cardiac output monitor in critically ill patients: a prospective criterion standard study.
OBJECTIVE: To evaluate the accuracy of a new continuous cardiac output monitor (one based on the thermodilution principle) in critically ill patients. DESIGN: Criterion standard study. SETTING: Multidisciplinary intensive care unit in a university hospital. PATIENTS: Fourteen critically ill patients, with different diseases, requiring pulmonary artery catheterization. INTERVENTIONS: In two patients with a left ventricular assist system, a defined, sudden 1 L/min change in cardiac output was carried through to evaluate the in vivo response time of the continuous cardiac output monitoring system. In the remaining 12 patients, cardiac output was altered by varying the dose of catecholamines, by volume loading, or by varying the level of sedation. In four patients, a rapid infusion of cold saline was given through a central venous catheter to test the performance of the system under these conditions. MEASUREMENTS AND MAIN RESULTS: Cardiac output was monitored continuously. A total of 163 (13 to 18 per patient) bolus determinations of cardiac output were performed, using the conventional thermodilution technique and simultaneously using the indocyanine green dye dilution technique. The range of cardiac output was 3.8 to 15.6 L/min. The results of the continuous thermodilution method were compared with the results of the bolus thermodilution and the dye dilution methods, respectively. The mean difference (bias) +/- SD of differences (precision) was 0.35 +/- 1.01 L/min for continuous vs. bolus thermodilution and 0.34 +/- 1.01 L/min for continuous thermodilution vs. indocyanine green dye dilution. Linear regression (correlation) analyses were y = 0.95x + 0.76 (r2 = .91) for continuous and bolus thermodilution and y = 0.93x + 0.87 (r2 = .91) for continuous thermodilution and dye dilution. The 75% in vivo response time was 10.5 mins. The infusion of cold isotonic saline led to erroneous continuous cardiac output values. When the conventional bolus thermodilution and dye dilution techniques were compared, mean difference was -0.01 +/- 0.54 L/min and the results of linear regression analyses were y = 0.97x + 0.22 (r2 = .97). CONCLUSIONS: Continuous cardiac output measurement using the thermodilution technique is reasonably accurate and is reliable and applicable in routine clinical practice, and therefore may add to patient safety. However, the response time is too slow for the immediate detection of acute changes in cardiac output. Some clinical conditions such as the rapid infusion of cold solutions can interfere with the continuous cardiac output measurement. Conventional bolus thermodilution and indocyanine green dye dilution methods showed good agreement and can be used interchangeably.
Long-term evaluation of a continuous intra-arterial blood gas monitoring system in patients with severe respiratory failure.
OBJECTIVE: The purpose of this study was to evaluate the reliability and accuracy of a new continuous intra-arterial blood gas monitoring system (IABG; PB3300, Puritan Bennett) over a prolonged period of time (> 7 days). DESIGN: Prospective criterion standard study. SETTING: Anesthesiological intensive care unit in a university hospital. PATIENTS: 11 sensors were tested in 10 mechanically ventilated patients with severe respiratory failure. INTERVENTIONS: PO2, PCO2, and pH measured using IABG were compared to values obtained from 2 conventional blood gas analyzers. The quality of blood pressure tracings was assessed using a scoring system consisting of 5 grades. RESULTS: The median study period was 205h/sensor (range: 169-506h). 320 blood samples were obtained. The ranges of measured parameters were: PO2 = 46-433 mmHg, PCO2 = 25-79 mmHg, pH = 7.25-7.55. The mean (SD) differences for the whole study period were: -4.3 (11.9) mmHg for PO2, for the clinically important range (PO2 < 150 mmHg) -1.9 (5.4) mmHg, -2.8 (4.5) mmHg for PCO2, and -0.03 (0.04) for the pH value. The MD (SD) in relation to the sensor lifetime were for days 1-3: -1.1 (5.1) mmHg for PO2, -0.4 (3.9) mmHg for PCO2, and -0.01 (0.03) for the pH value; for days 4-6: -1.5 (6.0) mmHg for PO2, -3.3 (4.0) mmHg for PCO2, and -0.03 (0.03) for the pH value; for days 7-9: -2.5 (4.7) mmHg for PO2, -5.1 (4.6) mmHg for PCO2, and -0.04 (0.04) for the pH value; for days > 9: -4.9 (4.4) mmHg for PO2, -5.3 (4.1) mmHg for PCO2, and -0.05 (0.03) for the pH value. CONCLUSIONS: The IABG reliably measured blood gases and pH values with acceptable clinical performance based on the overall results. There was, however, a decline in the agreement of the sensors and conventional values with increasing sensor lifetime. The mean differences (bias) and the standard deviation of differences (precision) of PO2, PCO2 and the pH values were acceptable for clinical purposes up to day 6. The arterial blood pressure tracings and blood withdrawal were not adversely affected. No side effects due to the sensors occurred. In summary, a prolonged sensor use for a period of up to 6 days appears to be reasonable. This system offers on-line information on oxygenation, ventilation, and acid-base status and allows immediate detection of acute and potentially life-threatening events.
Thermodilution cardiac output may be incorrect in patients on venovenous extracorporeal lung assist.
Cardiac output measurement is part of routine monitoring in critically ill patients. In patients on extracorporeal lung assist, thermodilution cardiac output measurement may lead to erroneous results caused by indicator loss into the extracorporeal circuit. Seven patients on venovenous extracorporeal lung assist were studied using different extracorporeal blood flows. We compared conventional thermodilution cardiac output determinations with dye dilution cardiac output measurement, with dye injection into the pulmonary artery. The latter method is not affected by the extracorporeal circuit. The conventional thermodilution method overestimated cardiac output up to a maximum of 300%, providing results up to 10 L/min higher than true cardiac output. The mean difference between thermodilution and true cardiac output as determined by dye dilution with pulmonary artery indicator injection was 3.0 +/- 2.41 L/min. There was no correlation between thermodilution cardiac output values and true cardiac output (r = 0.06). We conclude that conventional thermodilution is not a suitable method for cardiac output measurement in patients on extracorporeal lung assist, especially if high extracorporeal blood flows are applied.
Isovolemic hemodilution alters the ratio of whole-body to large-vessel hematocrit (F-cell ratio). A prospective, randomized study comparing the volume effects of hydroxyethyl starch 200,000/0.62 and albumin.
OBJECTIVE: To evaluate potential changes in the ratio of whole-body/large-vessel hematocrit (f-cell ratio) during isovolemic hemodilution and to compare the volume effects of 2 different plasma exchange solutions (hydroxyethyl starch 200,000/0.62 6% and human albumin 5%). DESIGN: Prospective, randomized, controlled trial. SETTING: Operating theater in a university hospital. PATIENTS: 24 gynecological patients scheduled for elective surgery. INTERVENTIONS: Isovolemic hemodilution was performed using 2 different plasma exchange solutions. Plasma volume was determined using dye dilution technique before and after hemodilution. The volume of withdrawn blood was measured from the change in weight of the blood bags taking into account the specific gravity of blood. RESULTS: The volume of administered plasma exchange solutions exceeded the amount of withdrawn blood by 80 +/- 47 ml (p < 0.001). Plasma volume was 3,067 +/- 327 ml before and 3,517 +/- 458 ml after hemodilution. Using red cell volumes calculated from measured plasma volumes and peripheral hematocrit, a deficit of 249 +/- 133 ml (p < 0.0001) in red cells after hemodilution appeared with the measured withdrawn red cell volumes taken into account. This finding can be explained by a change in the f-cell ratio during isovolemic hemodilution. The volume effect of the exchange solutions was 1.05 for hydroxyethyl starch and 0.95 for albumin. CONCLUSIONS: The results demonstrate that a change in the f-cell ratio occurs during isovolemic hemodilution. The estimation of red cell volume or plasma volume changes by using either the hematocrit or plasma or red cell volume determinations together with the hematocrit may lead to erroneous results.
[Noninvasive ventilation after lung transplantation].
BACKGROUND: Non-invasive mechanical ventilation (NIPPV) is an accepted choice of treatment in patients with chronic pulmonary disease and/or acute respiratory failure. Recently NIPPV was also proposed in the postoperative weaning period. PATIENTS AND METHODS: Six of 30 patients after lung transplantation were were extubated despite a weaning failure was predicted using well accepted weaning criteria. Therefore, the 6 patients were treated with intermittent-noninvasive ventilation using assisted modes of mechanical ventilation (PSV/CPAP). RESULTS: Both, oxygenation (increase in paO2: 18 mm Hg during PSV, 11 mm Hg during CPAP) and pulmonary mechanics (decrease in respiratory rate: 14/min during PSV, 10/min during CPAP; increase in tidal volume: 5 ml/kg during PSV, 3 ml/kg KG during CPAP) improved and the energy expenditure decreased (19% during PSV, 12% during CPAP). CONCLUSION: Non-invasive ventilation after lung transplantation enables earlier extubation and prevents weaning failure.
Low-dose hydrocortisone infusion attenuates the systemic inflammatory response syndrome. The Phospholipase A2 Study Group.
There is increasing evidence that the hypercortisolemia in inflammatory diseases suppresses the elaboration of proinflammatory cytokines, thus protecting the host from its own defence reactions. In severe sepsis and septic shock cortisol levels are usually elevated, but some patients may have relative adrenal insufficiency. This may contribute to the overwhelming systemic inflammatory response syndrome. We evaluated the impact of low-dose hydrocortisone infusion (10 mg/h) on the course of the systemic inflammatory response syndrome. This dose corresponds to a maximum secretory rate of cortisol achieved in corticotropin-stimulated healthy humans. In a prospective observational study 57 surgical patients with severe sepsis or septic shock were studied, of which in addition to the conventional treatment 12 patients were infused with low-dose hydrocortisone, and 45 were treated without any corticosteroid. In the longitudinal analysis the systemic inflammatory response--as judged by body temperature, cardiovascular response, and kinetics of inflammatory mediators such as phospholipase A2, C-reactive protein, and neutrophil elastase--started to differ in favor of the hydrocortisone-treated patients after 2 days of treatment (P < 0.05, Mann-Whitney U test). The difference disappeared after withdrawal of exogenous cortisol. Shock reversal was achieved in all patients treated with low-dose hydrocortisone. The data provide evidence that low-dose hydrocortisone infusion attenuates the systemic inflammatory response in human septic shock. From an immunological point of view a relative cortisol deficiency may contribute to the amplified immune response in systemic inflammatory diseases. A randomized clinical trial must clarify the impact of low-dose hydrocortisone infusion on the clinical course and outcome of septic shock patients.
[Continuous intravascular blood gas analysis. Clinical evaluation of a new fiber optic monitor].
Continuous monitoring of blood gases and pH could add substantially to patient safety. During the last decade, efforts have been made to develop continuous optochemical blood gas sensors. The initial evaluation of such fibreoptic-based systems showed major patient-interface problems [11]. We evaluated a new intra-arterial blood gas monitoring system (PB3300, Puritan-Bennett, Carlsbad CA) under routine clinical conditions. METHODS. After institutional review board approval and with written informed consent, 38 sensors were tested in 25 patients with acute respiratory failure (e.g., the acute respiratory distress syndrome, complications after lung transplantation). Two conventional bench-top blood gas analysers (ABL 520 and ABL 300, Radiometer, Copenhagen) served as criterion standards. The mean differences (bias) and standard deviations (SD) of the differences (precision) were calculated according to the method of Bland and Altman [2]. In addition, linear regression analysis and correlation coefficients were calculated. The quality of blood pressure tracings was assessed using a grading system. RESULTS. The median sensor lifetime was 81.3 h; 869 blood samples (median 14 per sensor) were analysed for the comparison of continuous and conventional blood gas analysis. The ranges for measured parameters were: pH: 6.92 to 7.55; PCO2: 20 to 83 torr; PO2: 31 to 518 torr. The mean differences (SD) were: pH: -0.03 (0.03) or -0.4 (0.4)%; PCO2: -2.6 (4.1) torr or -6.9 (10.9)%; PO2: -3.4 (10.5) torr or -2.9 (7.0)%. The results of linear regression analysis and the correlation coefficients are depicted in Table 2. The mean grade of blood pressure tracings was satisfactory for the clinical setting. CONCLUSIONS. The continuous blood gas monitor is sufficiently accurate and precise for clinical use. Bias and precision are better than those known from former studies evaluating fibreoptic blood gas monitors under experimental conditions [7]. Cost-effectiveness was not an issue of this study.
Continuous intra-arterial blood gas and pH monitoring in critically ill patients with severe respiratory failure: a prospective, criterion standard study.
OBJECTIVE: To evaluate the routine clinical performance of a new intra-arterial fiberoptic blood gas sensor that provides continuous PO2, PCO2, and pH monitoring. DESIGN: Criterion standard study under routine clinical conditions. SETTING: Intensive care unit (ICU) in a university hospital. PATIENTS: Twenty-two sensors were tested in 13 patients with acute respiratory failure, including two patients receiving veno-venous extracorporeal lung assist. Patient selection was based on the necessity of frequent blood gas monitoring. MEASUREMENTS: Sensor-deprived PO2, PCO2, and pH values were compared with values obtained using two different conventional laboratory blood gas analyzers located in the ICU. The median study period was 72 hrs per sensor (range 8 to 170 hrs). The quality of blood pressure readings with the sensor introduced through the arterial catheter was assessed by a grading system. RESULTS: Mean differences between sensor-derived values and the average values of the two conventional blood gas analyzers were as follows: PO2 -2.4 +/- 6.5 (SD) torr (-0.3 +/- 0.9 kPa), PCO2 -2.9 +/- 3.9 torr (-0.4 +/- 0.5 kPa), and pH -0.04 +/- 0.03. Correlation coefficients were 0.99 (PO2), 0.94 (PCO2), and 0.89 (pH), respectively. The agreement between the two methods for PO2 measurement was better for the clinically important range of values (PO2 < 150 torr [< 20 kPa]) than for all measured PO2 values (range 30 to 522 torr [4 to 69.6 kPa]). Blood withdrawal and pressure readings were not adversely affected by the sensor. No side effects due to the insertion of the sensor were observed. CONCLUSIONS: The degree of agreement of intra-arterial blood gas sensor values with conventional blood gas analysis is within an acceptable range for routine clinical purposes. Acute changes in measured values are detected reliably. Continuous intra-arterial blood gas analysis can add substantially to the safety of patients with acute respiratory failure and can reduce blood sampling requirements for blood gas analysis.
Determination of plasma volume with indocyanine green in man.
We investigated the feasibility of using indocyanine green (ICG) for plasma volume (PV) determination in man. Duplicate PV measurements were carried out in 23 healthy subjects to test repeatability. ICG (0.25 mg/kg) was injected intravenously into one arm and venous blood was withdrawn from the opposite arm. Optical density of plasma samples from minute 3 to 9 was measured in a densitometer. ICG concentration at injection time was determined by monoexponential extrapolation. The mean (SD) difference (MD) was -23 ml (183) or -0.6% (5.7%). Linear regression revealed PV2 = 0.92.PV1 + 226 (r = 0.92). The PV values corresponded well with data from other studies. In 26 surgical patients PV was determined using two methods: 1) the same as in healthy subjects and 2) using a modification of this method in whole blood (PVB). For PVB measurement blood was drawn through a cuvette-densitometer from an arterial line. Calculations were the same as in PV determination except for the use of hematocrit to achieve plasma concentrations of ICG from whole blood. In patients MD were -53 ml (144) or -1.3% (4.3) for PV and -19 ml (161) or -0.3% (5.1) for PVB. Comparing PVB and PV revealed MD = -113 ml (149) or -3.3% (4.2). The whole blood method is easier to perform and reduces blood waste to almost zero. In conclusion, ICG is a suitable tracer for PV determination.
[Fulminant pulmonary embolism in the 35th gestational week. Sonographic detection of a thrombus in the inferior vena cava with normal cavography].
Pulmonary embolism is the most common cause of maternal death during pregnancy. CASE REPORT. We report a 28-year-old obstetric patient (35th gestational week) who was admitted to the hospital because of intermittent vaginal bleeding caused by placenta totalis et accreta. Eleven days after admission she suffered a cardiac arrest. After cardiopulmonary resuscitation, an emergency caesarian section was performed and a healthy child was delivered. Abdominal sonography (B-mode) showed a floating thrombus in the inferior vena cava. Perfusion scintigraphy and cavography were normal; a computed tomography i.v. contrast medium study confirmed the presence of the thrombus. An open thrombectomy was performed to protect the patient from further pulmonary emboli. After 8 days she left the intensive care unit without residual complications. CONCLUSION. This case emphasises the importance of bedside sonography as a diagnostic method of identifying the source of a thrombus in patients with suspected pulmonary embolism.
[Subcapsular hematoma of the liver in HELLP syndrome. An interdisciplinary emergency].
The HELLP-syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets), known as a complication during pregnancy, is associated with preeclampsia and may cause subcapsular liver hematomas. In case of hepatic rupture the lives of mother and unborn are threatened. Therefore, an interdisciplinary diagnostic and therapeutic approach is discussed and compared to two examples. The diagnosis of subcapsular liver hematoma must lead to urgent delivery through Cesarean section. Thereafter, the surgeon may decide between observation on an intensive care unit and urgent operation in case of hepatic rupture, without endangering the unborn.
Haemodynamic improvement in refractory septic shock with cortisol replacement therapy.
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Continuous intra-arterial oximetry, pulse oximetry, and co-oximetry during cardiac surgery.
This study evaluated arterial catheter oximetry versus pulse oximetry in eight patients (ASA III-IV) who underwent cardiac surgery. Co-oximeter saturation values served as the standard. Arterial oxygen saturation was determined simultaneously with these three methods at 162 prospectively defined points of measurement before, during, and after cardiopulmonary bypass (CPB). At the same times before and after CPB, arterial, pulmonary arterial, and central venous pressures, and cardiac output determinations were recorded. Saturation readings were obtained in more than 99% of measurements with catheter oximetry and in only 59% to 84% of measurements with pulse oximetry. Failure of pulse oximetry correlated with low mean arterial pressures and low cardiac outputs, but not with high systemic vascular resistance. The mean saturation values determined by catheter oximetry as well as by pulse oximetry differed from the mean values obtained by co-oximetry by less than 1% (= bias). The standard deviations of the individual differences between readings of catheter or pulse oximetry and readings of co-oximetry (= precision) were +/- 0.5% to +/- 1.0% for catheter oximetry and +/- 1.0% to +/- 1.2% for pulse oximetry. In summary, catheter oximetry was superior to pulse oximetry with regard to obtaining readings and to reliability of the obtained readings. Invasiveness and high costs influence the decision as to whether to use catheter oximetry, but if reliable and precise measurements of saturation are important at any time during surgery, pulse oximetry is an insufficient method and co-oximetry is a time-consuming method of analysis, whereas catheter oximetry is quick, reliable, and precise.
Effect of interpleural morphine on postoperative pain and pulmonary function after thoracotomy.
We have investigated the effect of interpleural morphine on postoperative pain and pulmonary function after thoracotomy. At the end of surgery, an interpleural catheter was inserted in 17 patients and, in a double-blind and randomized manner, either a bolus of morphine 2.5 mg interpleurally (i.p.) and normal saline i.v. (group I) or, as a control for systemic absorption, morphine 2.5 mg i.v. and i.p. saline (group II) was injected. After the initial bolus, a continuous infusion of morphine 0.5 mg h-1 i.p. and saline i.v. (group I) or morphine 0.5 mg i.v. and saline i.p. (group II) was maintained for 24 h. Postoperative pain was assessed by a visual analogue scale, a numerical rating scale and the McGill Pain Questionnaire. Pulmonary function was assessed by spirometry. Supplementary analgesics, side effects, degree of sedation, vital signs and chest tube drainage were recorded. All variables were assessed on the day before surgery and 1, 2, 3, 4, 5, 6 and 24 h and 7 days after surgery. Supplementary morphine was given upon request. There was no significant difference in any pain measure or postoperative pulmonary function variable between the groups. We conclude that, after thoracotomy, interpleural morphine does not provide superior analgesia or improve pulmonary function compared with systemic morphine.