Outcome of acute respiratory distress syndrome in university and non-university hospitals in Germany.

BACKGROUND: This study investigates differences in treatment and outcome of ventilated patients with acute respiratory distress syndrome (ARDS) between university and non-university hospitals in Germany. METHODS: This subanalysis of a prospective, observational cohort study was performed to identify independent risk factors for mortality by examining: baseline factors, ventilator settings (e.g., driving pressure), complications, and care settings-for example, case volume of ventilated patients, size/type of intensive care unit (ICU), and type of hospital (university/non-university hospital). To control for potentially confounding factors at ARDS onset and to verify differences in mortality, ARDS patients in university vs non-university hospitals were compared using additional multivariable analysis. RESULTS: Of the 7540 patients admitted to 95 ICUs from 18 university and 62 non-university hospitals in May 2004, 1028 received mechanical ventilation and 198 developed ARDS. Although the characteristics of ARDS patients were very similar, hospital mortality was considerably lower in university compared with non-university hospitals (39.3% vs 57.5%; p = 0.012). Treatment in non-university hospitals was independently associated with increased mortality (OR (95% CI): 2.89 (1.31-6.38); p = 0.008). This was confirmed by additional independent comparisons between the two patient groups when controlling for confounding factors at ARDS onset. Higher driving pressures (OR 1.10; 1 cmH2O increments) were also independently associated with higher mortality. Compared with non-university hospitals, higher positive end-expiratory pressure (PEEP) (mean ± SD: 11.7 ± 4.7 vs 9.7 ± 3.7 cmH2O; p = 0.005) and lower driving pressures (15.1 ± 4.4 vs 17.0 ± 5.0 cmH2O; p = 0.02) were applied during therapeutic ventilation in university hospitals, and ventilation lasted twice as long (median (IQR): 16 (9-29) vs 8 (3-16) days; p < 0.001). CONCLUSIONS: Mortality risk of ARDS patients was considerably higher in non-university compared with university hospitals. Differences in ventilatory care between hospitals might explain this finding and may at least partially imply regionalization of care and the export of ventilatory strategies to non-university hospitals.

Aerosol delivery by an ultrasonic nebulizer during different mechanical ventilation settings in a lung model--a pilot study.

UNLABELLED: Aerosol delivery of Iloprost is a promising therapeutic approach. The aim of this study was to determine the output of an ultrasonic nebulizer in different ventilation set-ups at the tip of different endotracheal tubes. METHOD: In set-up A, an ultrasonic nebulizer was connected directly to the endotracheal tube. In set-up B, the nebulizer was incorporated into the inspiratory limb of the ventilator circuit; a bypass arrangement allowed to selectively direct the expiratory air discharged from the model lung. The test lungs were ventilated through a standard endotracheal tube (ET) and through a double-lumen tube (DLT). The nebulizer was filled with 5 ml of a Tc-99m 0.9%-NaCl solution. After nebulization, distribution of radioactivity was detected by gamma scintigraphy. RESULTS: Set-up A, ventilation in volume-controlled mode (VCV) via an ET: Delivered dose (1.61 +/- 0.41 ml), nebulization time 10.13 +/- 1.71 min. Set-up A, pressure-controlled ventilation (PCV), via a DLT: Delivered dose (1.33 +/- 0.88 ml), nebulization time 13.27 +/- 2.58 min. Set-up B, VCV mode via an ET: Delivered dose (1.57 +/- 0.44 ml), nebulization time (25.9 +/- 3.8 min). Set-up B, PCV mode, via a DLT: Delivered dose (1.3 +/- 0.17 ml), nebulization time (25.6 +/- 4.0 min). Set-up B did not yield a significantly higher output (p < 0.05), but the nebulization time was significantly longer (p > 0.05) compared with set-up A. CONCLUSION: Set-ups which involve connecting the nebulizer directly to an ET or a DLT exhibit sufficient output of aerosol and short nebulization times.

Thromboelastometry-guided administration of fibrinogen concentrate for the treatment of excessive intraoperative bleeding in thoracoabdominal aortic aneurysm surgery.

OBJECTIVE: Thoracoabdominal aortic aneurysm operations are associated with extensive blood loss and high requirements for allogeneic blood product transfusion. We assessed the efficacy of intraoperative post-cardiopulmonary bypass administration of fibrinogen concentrate in elective thoracoabdominal aortic aneurysm surgery. METHODS: In a retrospective group (group A, n = 12) of patients undergoing elective thoracoabdominal aortic aneurysm surgery, clinically relevant diffuse bleeding after weaning from cardiopulmonary bypass was treated with allogeneic blood products (platelet concentrates, followed by fresh frozen plasma) according to a predetermined algorithm. In a prospective group (group F, n = 6) a first therapy step with fibrinogen concentrate was added to the algorithm. The dose of fibrinogen concentrate was estimated by using thromboelastometric data (ROTEM FIBTEM). Before each step of hemostatic therapy, blood loss in the range of 60 to 250 g per 5 minutes was confirmed. RESULTS: In group F, administration of 7.8 +/- 2.7 g of fibrinogen concentrate established hemostasis, completely avoiding intraoperative transfusion of fresh frozen plasma and platelet concentrates. Transfusion of blood products after cardiopulmonary bypass and during the 24 hours after surgical intervention was markedly lower in group F than in group A (2.5 vs 16.4 units; 4/6 patients in group F required no transfusion of blood products), as was 24-hour drainage volume (449 vs 1092 mL). Fibrinogen plasma levels, standard coagulation parameters, and hemoglobin and hematocrit values were comparable between the 2 groups on the first postoperative day. CONCLUSIONS: FIBTEM-guided post-cardiopulmonary bypass administration of fibrinogen concentrate resulted in improved intraoperative management of coagulopathic bleeding in thoracoabdominal aortic aneurysm operations and reduced transfusion and 24-hour drainage volume.

Skin impedance correlates to sedation grade, plasma propofol concentrations and bispectral index during a target-controlled infusion of propofol.

BACKGROUND AND OBJECTIVE: Sympathetic activity, measured as changes in electrical skin impedance, may be used to assess the adequacy of general anaesthesia. The aim of this prospective study was to evaluate electrical skin impedance in comparison with bispectral index values and the Observer's Assessment of Alertness and Sedation (OAAS) scale during propofol infusion. METHODS: Electrical skin impedance was measured with an electrosympathicograph. In 22 patients and eight healthy volunteers, anaesthesia was induced and maintained with propofol that was administered via a target-controlled infusion pump at increasing plasma concentrations. Bispectral index, electrosympathicograph and OAAS values were compared at six successive predicted target plasma concentrations (T 1-6: 0, 1.3, 1.7, 2.0, 2.4 and 2.8 microg ml(-1)). RESULTS: The changes in the electrical skin impedance measured with the assistance of the electrosympathicograph correlated with the changes in bispectral index values at each measurement time point and during the whole course (P < 0.0001), with the target plasma propofol concentrations (P < 0.0001), and with the OAAS scale (P < 0.0001). CONCLUSION: The observed correlations between electrical skin impedance, predicted plasma concentrations of propofol and OAAS scale appear to justify further investigation of skin impedance as a depth of anaesthesia monitor.

The effects of fibrinogen levels on thromboelastometric variables in the presence of thrombocytopenia.

BACKGROUND: The binding of fibrinogen and fibrin to platelets is important in normal hemostasis. The extent of platelet-fibrin interaction can be measured as the viscoelastic strength of clot by rotational thromboelastometry (ROTEM). In this study, we investigated the effect of fibrinogen concentration and its relative contribution to overall clot strength using ROTEM. METHODS: Blood samples were collected from healthy volunteers. The effects of platelet count on clot strength, determined by maximum clot elasticity (MCE), were evaluated on ROTEM using platelet-rich plasma (PRP) adjusted with autologous plasma to generate a range of platelet counts. PRPs were adjusted to 10 x 10(3) mm(-3), 50 x 10(3) mm(-3), and 100 x 10(3) mm(-3) and spiked with fibrinogen concentrates at 550 and 780 mg/dL. The effect of fibrin polymerization on clot strength, independent of platelet attachment, was analyzed by the cytochalasin D-modified thromboelastometry (FIBTEM) method. Additional retrospective analysis of clot strength (MCE) in two groups of thrombocytopenic patients was conducted. RESULTS: Clot strength (MCE) decreased at a platelet count below 100 x 10(3) mm(-3), whereas increases in MCE peaked and reached a plateau at platelet counts from 400 x 10(3) mm(-3). Increasing fibrinogen concentrations in PRP increased clot strength in a concentration-dependent manner, even at low platelet counts (10 x 10(3) mm(-3)). The positive correlation between clot strength and plasma fibrinogen level was also confirmed in the analysis of the data obtained from 904 thrombocytopenic patients. CONCLUSIONS: These in vitro and clinical data indicate that the clot strength increases in a fibrinogen concentration-dependent manner independent of platelet count, when analyzed by ROTEM. The maintenance of fibrinogen concentration is critical in the presence of thrombocytopenia. EXTEM (extrinsic activation) and FIBTEM may be useful in guiding fibrinogen repletion therapy.

Percutaneous interventions for treating ischemic complications of aortic dissection.

The aim of this study was to evaluate the role of percutaneous interventions in treating ischemia complicating aortic dissection. Forty-five patients with ischemia complicating aortic dissection were treated by balloon fenestration, true lumen stenting, angioplasty, or thrombolysis. Clinical and laboratory examinations were performed before and after intervention, and at the end of follow-up (median 37 months). Eighteen dissections were acute, 9 sub-acute, and 18 chronic. Mesenterohepatic ischemia resolved in 16 of 18 patients; lactate and SGOT values fell from 2.89 to 1.23 mmol/L (p=0.006) and from 165.9 to 59.7 U/L (p=0.034), respectively. In patients with renal ischemia, creatinine levels fell from 360.1 to 196.3 micromol/L (p=0.007) accompanied by a significant reduction in blood pressure. Limb-threatening ischemia resolved in three of four patients; in 21 claudicants, the mean walking distance improved from 272 to 1,283 m (p=0.001). Spinal ischemia resolved completely or partially in six of eight patients. Adjunctive surgical measures were necessary in six patients. Overall 30-day mortality in the 45 patients was 6.7%; all three deaths were in patients with acute dissections (mortality in this subgroup 16.7%). Ischemia complicating aortic dissection can be effectively treated by percutaneous interventions resulting in good early and mid-term outcomes.

Prevention of central venous catheter related infections with chlorhexidine gluconate impregnated wound dressings: a randomized controlled trial.

The objective of the study was to evaluate the effectiveness of chlorhexidine-impregnated sponges for reducing catheter-related infections of central venous catheters inserted for cancer chemotherapy. The method used was a randomized, prospective, open, controlled clinical study (three-step group sequential analysis protocol). The patients were from two high dependency units at a university hospital undergoing chemotherapy for haematological or oncological malignancies requiring central venous catheters (CVCs) expected to remain in place for at least 5 days. Six hundred and one patients with 9,731 catheterization days were studied between January 2004 and January 2006. Patients admitted for chemotherapy received chlorhexidine and silver sulfadiazine-impregnated triple-lumen CVCs under standardized conditions and were randomized to the groups receiving a chlorhexidine gluconate-impregnated wound dressing or a standard sterile dressing. Daily routine included clinical assessment of the insertion site (swelling, pain, redness), temperature, white blood count and C-reactive protein. Catheters remained in place until they were no longer needed or when a CVC-related infection was suspected. Infection was confirmed with blood cultures via the catheter lumina and peripheral blood cultures according to the time-to-positivity method. Six hundred and one patients were included. The groups were comparable with respect to demographic and clinical data. The incidence of CVC-related infections were 11.3% (34 of 301) and 6.3% (19 of 300) in the control and chlorhexidine-impregnated wound dressing groups, respectively (p=0.016, relative risk 0.54; confidence interval 0.31-0.94). Especially, catheter-related infections at internal jugular vein insertions could be reduced (p=0.018). No adverse effects related to the intervention were observed. The use of chlorhexidine-impregnated wound dressings significantly reduced the incidence of CVC-related infections in patients receiving chemotherapy.

Complex myograph allows the examination of complex muscle contractions for the assessment of muscle force, shortening, velocity, and work in vivo.

BACKGROUND: The devices used for in vivo examination of muscle contractions assess only pure force contractions and the so-called isokinetic contractions. In isokinetic experiments, the extremity and its muscle are artificially moved with constant velocity by the measuring device, while a tetanic contraction is induced in the muscle, either by electrical stimulation or by maximal voluntary activation. With these systems, experiments cannot be performed at pre-defined, constant muscle length, single contractions cannot be evaluated individually and the separate examination of the isometric and the isotonic components of single contractions is not possible. METHODS: The myograph presented in our study has two newly developed technical units, i.e. a). a counterforce unit which can load the muscle with an adjustable, but constant force and b). a length-adjusting unit which allows for both the stretching and the contraction length to be infinitely adjustable independently of one another. The two units support the examination of complex types of contraction and store the counterforce and length-adjusting settings, so that these conditions may be accurately reapplied in later sessions. RESULTS: The measurement examples presented show that the muscle can be brought to every possible pre-stretching length and that single isotonic or complex isometric-isotonic contractions may be performed at every length. The applied forces act during different phases of contraction, resulting into different pre- and after-loads that can be kept constant - uninfluenced by the contraction. Maximal values for force, shortening, velocity and work may be obtained for individual muscles. This offers the possibility to obtain information on the muscle status and to monitor its changes under non-invasive measurement conditions. CONCLUSION: With the Complex Myograph, the whole spectrum of a muscle's mechanical characteristics may be assessed.

Comparison of inhaled iloprost and nitric oxide in patients with pulmonary hypertension during weaning from cardiopulmonary bypass in cardiac surgery: a prospective randomized trial.

OBJECTIVE: The objective of this study was to compare the efficacy of inhaled iloprost and nitric oxide (iNO) in reducing pulmonary hypertension (PHT) during cardiac surgery immediately after weaning from cardiopulmonary bypass (CPB). DESIGN: A prospective randomized study. SETTING: A single-center university hospital. PARTICIPANTS: Forty-six patients with PHT (mean pulmonary artery pressure (mPAP) > or = 26 mmHg preoperatively at rest, after anesthesia induction, and at the end of CPB) scheduled to undergo cardiac surgery were enrolled. INTERVENTIONS: Patients were randomly allocated to receive iloprost (group A, n = 23) or iNO (group B, n = 23) during weaning from CPB. MEASUREMENTS AND MAIN RESULTS: Heart rate, mean arterial pressure, central venous pressure, pulmonary artery pressure (PAP), pulmonary capillary wedge pressure, and left atrial pressure were recorded continuously. Iloprost and iNO were administered immediately after the end of CPB before heparin reversal. Both substances caused significant reductions in mean PAP (mPAP) and pulmonary vascular resistance (PVR) and significant increases in cardiac output 30 minutes after administration (p < 0.0001). However, in a direct comparison, iloprost caused significantly greater reductions in PVR (p = 0.013) and mPAP (p = 0.0006) and a significantly greater increase in cardiac output (p = 0.002) compared with iNO. CONCLUSIONS: PHT after weaning from CPB was significantly reduced by the selective pulmonary vasodilators iNO and iloprost. However, in a direct comparison of the 2 substances, iloprost was found to be significantly more effective.

Effects of pharmacological intervention on coagulopathy and organ function in xenoperfused kidneys.

BACKGROUND: Following pig to primate kidney transplantation, xenogenic activation of the coagulation (XAC) system of the recipient eventually leading to organ dysfunction and disseminated intravascular coagulation (DIC) can be observed. METHODS: Using an ex-vivo perfusion circuit based on low-dose heparin-mediated anticoagulation and exogenous complement inhibition by C1- Inhibitor (C1-Inh), we have analysed XAC following contact of human blood with porcine endothelium. Porcine kidneys (n = 23) were recovered following in situ cold perfusion with histidine-tryptophan-ketoglutarate (HTK) solution and were connected to a perfusion circuit utilizing freshly drawn pooled human AB blood. RESULTS: Kidney survival during organ perfusion with human blood, CI-Inh, heparin but without any further pharmacological intervention was 126 +/- 78 min. XAC was observed with significantly elevated levels of D-dimer and thrombin antithrombin complexes (TAT). Pharmacological intervention with nitroprusside and prostacycline resulted in increased organ survival (220 +/- 28 min and 180 +/- 85 min respectively) but failed to inhibit XAC. In contrast, addition of activated protein C (APC) significantly reduced the increase in D-dimer and TAT and prolonged organ survival to 240 min (+/-0). On histology, no remarkable signs of XAC were observed. CONCLUSIONS: We conclude that exogenous APC is able to reduce XAC in this ex vivo perfusion model.

Renal transplantation normalized hydrogen peroxide production of neutrophils within the first day.

BACKGROUND: Hemodialysis patients are in a state of oxidant stress. In renal transplantation reactive oxygen species (ROS) are considered to be important factors of ischemia-reperfusion injury. Neutrophils produce ROS as part of the host defense against invading bacteria. This study was designed to investigate whether neutrophil function in hemodialysis patients is immediately affected by renal transplantation. METHODS: We evaluated the neutrophil respiratory burst and phagocytic activity in renal transplant patients with living-related donor (LRD) and cadaveric donor (CAD) grafts using flow cytometry techniques. Twenty patients (LRD = 6, CAD = 14) and 20 healthy volunteers were included in the study. Venous blood samples were drawn before anesthesia, 5 min before reperfusion, 1 h and 1, 3 and 7 days after reperfusion. RESULTS: Before surgery, a significant increase in hydrogen peroxide production in neutrophils was seen for both renal transplantation groups compared to healthy subjects. Within 24 h after reperfusion hydrogen peroxide production almost decreased to normal values. The phagocytic capacity of neutrophils was continuously depressed. There were no differences between the CAD and LRD groups. CONCLUSIONS: We found that the enhanced respiratory burst activity of patients with chronic renal failure decreased to normal values within 1 day following renal transplantation. Our results suggest that reduced respiratory burst activity resulting in a diminished risk of tissue damage by the uncontrolled production of ROS.

Prospective investigation into the influence of various stressors on skin impedance.

BACKGROUND: The control mechanisms during general anesthesia include circulation parameters and vegetative reactions. A possible way to quantify vegetative reactions is to measure the impedance of the skin. An activation of the eccrine sweat glands via sympathetic sudomotor fibers induces a secretion of sweat, which generates a drop in skin impedance. The aim of the present study was to investigate the influence which different stressors and measurement electrodes have upon skin impedance. MATERIAL AND METHOD: The changes in skin impedance and were measured after application of various stimuli (T1 value at rest, T2 acoustic stimulus, T3 visual stimulus, T4 tactile stimulus, T5 pain stimulus, T6 Valsalva manoeuvre, T7 forced inspiration/expiration). About 62 awake subjects underwent four standardized test sequences, during which several types of electrodes and recording sites (palmarly, plantarly) were explored. RESULTS: All physiological (T6-T7) and external stimuli (T2-T5) led to significant changes in skin impedance (14.9 +/- 18.2 kOmega) and heart rate. These changes happened independently of BMI, gender and measurement electrode types. The time it took to react to the stimuli was significantly shorter for palmar applications than that obtained from plantar sites. The reaction times were as follows: palmarly 1.2 +/- 0.5 seconds for solidgel electrodes and 1.15 +/- 0.5 seconds for hydrogel electrodes, plantarly 2.3 +/- 1.0 seconds for solidgel electrodes and 2.21 +/- 1.2 seconds for hydrogel electrodes. The forced inspiration and expiration manoeuvres generated greater variations in skin impedance than did pain stimulus and acoustic stimulus. Measurements that were performed with solidgel electrodes revealed significantly greater average decreases in skin impedance following exposure to a stimulus. CONCLUSION(S): External, but primarily also physiological stressors, generate direct and reproducible variations in skin impedance. Solidgel ECG electrodes should be used for all measurements.

Assessment of precision and reproducibility of a new myograph.

BACKGROUND: The physiological characteristics of muscle activity and the assessment of muscle strength represent important diagnostic information. There are many devices that measure muscle force in humans, but some require voluntary contractions, which are difficult to assess in weak or unconscious patients who are unable to complete a full range of voluntary force assessment tasks. Other devices, which obtain standard muscle contractions by electric stimulations, do not have the technology required to induce and measure reproducible valid contractions at the optimum muscle length. METHODS: In our study we used a newly developed diagnostic device which measures accurately the reproducibility and time-changed-variability of the muscle force in an individual muscle. A total of 500 in-vivo measurements of supra-maximal isometric single twitch contractions were carried out on the musculus adductor pollicis of 5 test subjects over 10 sessions, with ten repetitions per session. The same protocol was performed on 405 test subjects with two repetitions each to determine a reference-interval on healthy subjects. RESULTS: Using our test setting, we found a high reproducibility of the muscle contractions of each test subject. The precision of the measurements performed with our device was 98.74%. Only two consecutive measurements are needed in order to assess a real, representative individual value of muscle force. The mean value of the force of contraction was 9.51 N and the 95% reference interval was 4.77-14.25 N. CONCLUSION: The new myograph is a highly reliable measuring device with which the adductor pollicis can be investigated at the optimum length. It has the potential to become a reliable and valid tool for diagnostic in the clinical setting and for monitoring neuromuscular diseases.

In vivo myograph measurement of muscle contraction at optimal length.

BACKGROUND: Current devices for measuring muscle contraction in vivo have limited accuracy in establishing and re-establishing the optimum muscle length. They are variable in the reproducibility to determine the muscle contraction at this length, and often do not maintain precise conditions during the examination. Consequently, for clinical testing only semi-quantitative methods have been used. METHODS: We present a newly developed myograph, an accurate measuring device for muscle contraction, consisting of three elements. Firstly, an element for adjusting the axle of the device and the physiological axis of muscle contraction; secondly, an element to accurately position and reposition the extremity of the muscle; and thirdly, an element for the progressive pre-stretching and isometric locking of the target muscle. Thus it is possible to examine individual in vivo muscles in every pre-stretched, specified position, to maintain constant muscle-length conditions, and to accurately re-establish the conditions of the measurement process at later sessions. RESULTS: In a sequence of experiments the force of contraction of the muscle at differing stretching lengths were recorded and the forces determined. The optimum muscle length for maximal force of contraction was established. In a following sequence of experiments with smaller graduations around this optimal stretching length an increasingly accurate optimum muscle length for maximal force of contraction was determined. This optimum length was also accurately re-established at later sessions. CONCLUSION: We have introduced a new technical solution for valid, reproducible in vivo force measurements on every possible point of the stretching curve. Thus it should be possible to study the muscle contraction in vivo to the same level of accuracy as is achieved in tests with in vitro organ preparations.

Continuous monitoring of central venous oxygen saturation in neonates and small infants: in vitro evaluation of two different oximetry catheters.

BACKGROUND: Accurate assessment and monitoring of the cardiocirculatory function are essential during major pediatric and pediatric cardiac surgery. Monitoring of the central venous oxygen saturation (ScvO(2)) may be a better indicator of tissue oxygenation and derangement of cellular oxygen utilization than the more commonly used vital parameters. Therefore, we compared oxygen saturation measurements with thin fiberoptic oximetry catheters and standard blood gas oximetry in an in vitro setting. METHODS: Two different size continuous fiberoptic oximetry catheters (2-4-F) were inserted in an extracorporeal circuit filled with human red blood cells in normal saline (haematocrit 30%, flow 600 ml.min(-1)). The results of fiberoptic oximetry were then compared with standard blood gas oximetry for a wide range of different oxygen saturations using linear regression. RESULTS: The oxygen saturations found ranged from 9% to 100%. The results of the two different fiberoptic oximetry catheters correlated significantly (r = 0.99, P < 0.0001) with standard blood gas oximetry. CONCLUSION: The results of fiberoptic oximetry are nearly identical with standard blood gas oximetry for a wide range of different oxygen saturations. Thin oximetry catheters can be inserted percutaneously even in neonates and small infants. The continuous monitoring of ScvO(2) may be beneficial, especially in patients who are in danger of developing low cardiac output or sudden cardiovascular collapse.

Effectiveness and safety of internal rectilinear biphasic versus monophasic defibrillation in patients undergoing cardiac surgery.

BACKGROUND: Recently it has been shown that biphasic external shocks are more effective in the treatment of ventricular fibrillation (VF) compared with monophasic external shocks in terms of number of defibrillation attempts and maximal energy used for termination of VF. Biphasic defibrillators apply different biphasic impulse forms, depending on technology. To the authors' knowledge, there are no existing data concerning the effects of rectilinear biphasic internal shocks in patients undergoing cardiac surgery. The purpose of this study was to compare monophasic with rectilinear biphasic internal shock waveforms for termination of VF in patients undergoing cardiac surgery. METHODS: One hundred thirty-four patients scheduled for elective cardiac surgery were prospectively randomized either to monophasic (group A) or biphasic (group B) internal defibrillation. Defibrillation was started with 7 J and increased stepwise to 30 J in each group until successful termination of VF after aortic declamping. The number of defibrillations, as well as the cumulative and maximal energy for termination of VF, were determined. Preoperatively, intraoperatively, and postoperatively troponin T, total creatine phosphokinase (CPK), and CPK- MB isoenzymes were measured. RESULTS: In 64 patients (47%) VF occurred. The groups consisted of 32 patients each. The number of defibrillations (1.3 +/- 0.6 v 1.9+/- 1.2; p = 0.013), maximal energy per patient (7.9 +/- 2.5 v 11.6 +/- 7.32; p = 0.006), and cumulative energy (10.1 +/-6.1 v 21.3 +/- 24.1; p = 0.016) for successful termination of VF were significantly reduced in group B. Troponin T, CPK, and CPK-MB did not differ between groups. CONCLUSIONS: Results of this study indicate that rectilinear biphasic internal defibrillation is more effective in the treatment of VF during cardiac surgery than is monophasic defibrillation. However, no significant difference in myocardial damage could be detected between groups.