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Biomedical subjects

G Wimmer-Greinecker

Publications and source records attributed to G Wimmer-Greinecker.

At least 37 records · Page 2Linked to original sources
PubMed2001

Computer-enhanced totally endoscopic sequential arterial coronary artery bypass.

Minimally invasive coronary artery bypass grafting of the anterior wall using a left anterior small thoracotomy became a routine procedure within the last 3 years. The introduction of robotics into the cardiosurgical practice in 1998 has finally enabled totally endoscopic closed chest procedures. We report two patients with totally endoscopic left internal thoracic artery bypass grafting to the left anterior descending artery and the first diagonal branch in sequential arterial revascularization technique using the daVinci surgical system.

Cardiopulmonary Bypass↗
PubMed2001

Hemodynamics and gas exchange during carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting.

BACKGROUND: In addition to single-lung ventilation (SLV), positive-pressure CO2 insufflation is mandatory for totally endoscopic coronary artery bypass grafting. Studies on the effects of unilateral CO2 insufflation on hemodynamics produced controversial results, and bilateral insufflation has not been studied to our knowledge. The present study sought to investigate hemodynamics and gas exchange during unilateral and bilateral CO2 insufflation in patients who underwent totally endoscopic coronary artery bypass grafting. METHODS: Eleven hemodynamic and gas exchange variables were monitored during 22 totally endoscopic coronary artery bypass grafting procedures with unilateral (n = 17) or bilateral (n = 5) CO2 insufflation at a pressure of 10 to 12 mm Hg. Data were obtained at baseline with double-lung ventilation, after institution of SLV, during insufflation, after cardiopulmonary bypass during SLV, and after return to double-lung ventilation. RESULTS: Arterial oxygen tension decreased significantly during SLV, whereas the peak inspiratory pressure increased. In addition, central venous pressure and heart rate increased significantly during insufflation, but mean arterial pressure remained unchanged. Although the end-tidal CO2 pressure did not change, arterial carbon dioxide tension increased progressively to a maximum of 44.6 +/- 5.9 mm Hg during unilateral insufflation, and 55.7 +/- 14.6 mm Hg during bilateral insufflation (p < 0.05 versus baseline and between groups). Mixed venous oxygen saturation declined during SLV regardless of CO2 insufflation and recovered to baseline once double-lung ventilation was restarted. Left and right ventricular ejection fractions remained unaltered. No patient required inotropic or vasopressor support. CONCLUSIONS: Carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting with SLV had no adverse effects on hemodynamics. In contrast to a moderate increase of arterial carbon dioxide tension during unilateral insufflation, markedly elevated arterial carbon dioxide tension levels remain a cause of concern during bilateral insufflation.

Adult↗
PubMed2001

Correction of simple congenital heart defects in infants and children through a minithoracotomy.

BACKGROUND: Minimally invasive surgical techniques in pediatric cardiac surgery have evolved throughout the last 10 years. Advantages of minimally invasive procedures include excellent cosmetic results and superior postoperative outcome. However, safety of minimally invasive techniques has to be proven. METHODS: In 21 female infants and children, a right anterolateral thoracotomy was performed. Mean age was 7.1 years (0.5 to 16.6 years) and mean body weight was 20.8 kg (8.3 to 56 kg). The following defects were repaired: atrial septum defect type II (n = 14); partial atrioventricular septum defect (n = 3); partial anomalous pulmonary venous connection (n = 2); ventricular septum defect (n = 2); mitral valve insufficiency (n = 1); and resection of an embolized atrial septum defect occluder (n = 1). In two cases, aortic cross-clamping was performed by using a transthoracic clamp. In 5 patients, femoral cannulation was performed. Skin incisions were limited to 4 to 7 cm. RESULTS: There was no operative or late mortality. Mean operation time, bypass time, and aortic cross-clamp time were 138 (95 to 275), 72 (32 to 179), and 35 (12 to 120) minutes, respectively. Mean postoperative mechanical ventilation time, mean intensive care unit stay, and mean hospital stay were 3.9 hours (1 to 12 hours), 1.4 days (1 to 3 days), and 12 days (8 to 18 days), respectively. Postoperative complications included hemorrhage in 1 patient requiring surgical intervention. Mean follow-up period was 13.3 months (1 to 36 months). All patients were in New York Heart Association class I postoperatively. Trivial mitral insufficiency was evident in 1 patient operated for partial atrioventricular septum defect. CONCLUSIONS: A small right anterolateral thoracotomy as a minimally invasive technique in pediatric cardiac surgery is a safe and suitable alternative in the operative management of simple congenital heart defects. Cosmetic results are superior, however, improved postoperative outcome has to be proven.

Adolescent↗
PubMed2001

Conventional carbon dioxide application does not reduce cerebral or myocardial damage in open heart surgery.

BACKGROUND: Open heart surgery is associated with a significant risk of cerebral and myocardial dysfunction, which is attributed in part to air embolism from incompletely deaired cardiac chambers. To evaluate the impact of carbon dioxide (CO2) insufflation to the thoracic cavity, a prospective randomized study was designed. METHODS: A total of 62 elective patients were randomly assigned to CO2 insufflation (group I, n = 31) or control (group II, n = 31). According to the Parsonnet risk score, 16 patients in group I (52%) and 10 patients in group II (32%) were categorized as being at either high risk or extremely high risk. RESULTS: In group II, perioperative mortality was 16.1% (5 patients); in group I, 1 patient died (ns). Creatine kinase MB isoenzyme, as a marker of myocardial damage, was more elevated in group I after surgery (38.0 +/- 4.1 vs 28.0 +/- 2.1, p = 0.02). Neurocognitive test scores did not reveal significant postoperative differences between groups. CONCLUSIONS: Although mortality was lower with CO2 insufflation, no benefit could be demonstrated for markers of cardiac ischemic damage or neurocognitive outcome in this high-risk population. As CO2 concentrations in the thoracic cavity did not necessarily reach anticipated levels, our method of application is in question.

Aged↗
PubMed2001

Leukocyte filtration in the early reperfusion phase on cardiopulmonary bypass reduces myocardial injury.

Improved myocardial protection and cardiopulmonary bypass (CPB) have limited, but not abolished, intraoperative myocardial damage due to surgical reperfusion injury after release of the aortic crossclamp. In this double-blind, randomized study, we evaluated whether short-term leukocyte filtration during reperfusion may further reduce myocardial damage. Thirty-eight patients with coronary artery disease were randomly assigned to CPB with (group I; n = 19) or without leukocyte filtration (group II; n = 19). There was no difference in bypass time or crossclamp time between the groups. No patient in group I required catecholamines, whereas three patients in group II were supported with adrenaline or dobutamine on the first and second postoperative day. In addition, troponin T plasma levels were lower in group I (p < 0.05), whereas other markers for tissue injury (CK, CK-MB, LDH, S-GOT and S100B) did not differ. In conclusion, leukocyte filtration during reperfusion may further improve CPB by reducing myocardial damage.

Aged↗
PubMed2001

Timing of leukocyte filtration during cardiopulmonary bypass.

The effects of leukocyte filtration on the outcome of cardiac surgery with cardiopulmonary bypass (CPB) have been shown by numerous investigators. In the majority of cases a leukocyte filter is placed in the arterial line instead of a standard arterial line filter and used throughout CPB. However, protocols to optimize onset and duration of leukocyte filtration have not been sufficiently evaluated to date. In this paper, current efforts to improve such protocols are demonstrated and discussed. These efforts are based on studies of leukocyte pathogenicity during cardiac surgery. A first study (double-blind randomized) was performed in routine coronary artery bypass graft (CABG) patients to evaluate whether short-term leukocyte filtration during reperfusion by release of the aortic crossclamp would reduce reperfusion-associated myocardial damage. Further data compare the efficacy of three different filtration concepts to reduce CPB- and/or reperfusion-associated leukocyte pathogenicity. Clinical endpoints, standard laboratory variables and functional in vitro assays are provided and discussed.

Cardiopulmonary Bypass↗
PubMed2001

Abdominal complications after cardiac surgery.

OBJECTIVE: Abdominal complications after cardiac surgery are associated with a high mortality rate. Due to the absence of early specific clinical signs, diagnosis is often delayed. The present study seeks to determine predictive risk factors for subsequent gastrointestinal complications after cardiosurgical procedures. METHODS: Within 12 months, all patients (n = 1,116) who had undergone open heart surgery with cardiopulmonary bypass at our institution were studied for abdominal complications. To determine predictive factors, all case histories of the patients were analysed. RESULTS: Abdominal complications occurred in 23 (2.1%) patients during the postoperative intensive care unit (ICU) stay, ten of whom had to undergo subsequent abdominal surgery. Of these 23 patients, 20 died. Early complications occurred most likely on postoperative days 6 and 7, consisting of bowel ischaemia or hepatic failure. Late complications consisted of gastrointestinal bleeding, pseudomembraneous colitis, cholecystitis and septic rupture of a spleen. The relative risk for abdominal complications after cardiopulmonary bypass was highly increased in association with a cardiac index less than 2.0 l/min-1/(m2)-1 (22.1-fold), postoperative onset of atrial fibrillation (16.6-fold), emergency surgery (10.7-fold), need for vasopressors (10.1-fold), need for intra-aortic balloon counterpulsation (8.6-fold), and the need for re-exploration within the first 24 hours (8.4-fold). All patients with necrotic bowel disease had elevated serum lactate levels. Furthermore, both cardiopulmonary bypass and aortic clamping times were significantly prolonged in patients who developed gastrointestinal complications. CONCLUSIONS: A number of predictive factors has been described to contribute to the development of abdominal complications subsequently after cardiac surgery on cardiopulmonary bypass. Knowledge of these factors may lead to earlier identification of patients at increased risk and may allow for more efficient and earlier interventions.

Abdomen↗
PubMed2001

Heparin coating of the extracorporeal circuit combined with leukocyte filtration reduces coagulation activity, blood loss and blood product substitution.

BACKGROUND: Cardiopulmonary bypass is associated with activation of the coagulation cascade. Occasionally, this results in postoperative hemorrhage and consequently the need for blood products associated with increasing costs and risk of infection. Contact activation of the intrinsic coagulation pathway, and damage to cellular blood components with the release of proteolytic substances from neutrophil granulocytes have been linked to these coagulation disorders. METHODS: Eighteen routine CABG-patients were randomly assigned to totally heparin coated circuits (Bioline coating) combined with leukocyte filtration in a double blind protocol (group I), 34 patients served as controls (group II). Leukocyte filters were activated before release of the aortic crossclamp. Coagulation activity, postoperative blood loss, and substitution with blood products were assessed. RESULTS: Blood loss in the first 24h after surgery was significantly lower with combined application of heparin coating and leukocyte filters (group I) vs. controls (group II) (526+/-78 ml vs. 786+/-88 ml; p<0.05). Thrombin formation represented by prothrombin fragments 1+2 was significantly lower in group I vs. group II after declamping of the aorta (2.1+/-0. 3 nmol/L vs. 4.0+/-0.3 nmol/L; p<0. 05). Group I showed higher AT II plasma than group II (48.8+/-3.2% vs. 41.5+/-1.77%; p<0.05). CONCLUSIONS: Leukocyte filtration during reperfusion in heparin coated cardiopulmonary bypass circuits is associated with lower coagulation activation, decreased blood loss and reduced transfusion of packed red cells in elective CABG patients.

Aged↗
PubMed2000

Vitamins C and E protect isolated cardiomyocytes against oxidative damage.

There is considerable evidence that oxygen free radicals are involved in reperfusion injury of ischemic myocardium. Epidemiologic studies showed an inverse correlation between plasma levels of alpha-tocopherol (vitamin E) and ascorbic acid (vitamin C) and mortality from ischemic heart disease. The present study examines the influence of both vitamins on the toxic effects of singlet oxygen on isolated rat cardiomyocytes. Freshly isolated cardiomyocytes from adult rats were exposed to singlet oxygen which was generated by photoactivation of the photosensitive dye rose bengal (10(-7) M). This procedure induced irreversible hypercontracture in about 95% of rod-shaped cardiomyocytes within 15 min after onset of photoactivation of rose bengal. Pretreatment with vitamin C (10(-5) to 10(-2) M) or E (10(-6) to 10(-3) M) reduced the number of hypercontracted cells after exposure to singlet oxygen in a concentration-dependent manner. Simultaneous application of both vitamins (vitamin E 10(-6) M plus vitamin C 10(-5) M or vitamin E 10(-5) M plus vitamin C 10(-4) M) revealed a marked overadditive protective effect against oxidative damage as compared with the single application of each vitamin. Our data show that alpha-tocopherol and ascorbic acid exert direct protective actions on isolated cardiomyocytes against oxidative damage and provide an overadditive effect if administered simultaneously.

Animals↗
PubMed2000

Uncontrolled reoxygenation by initiating cardiopulmonary bypass is associated with higher protein S100 in cyanotic versus acyanotic patients.

BACKGROUND: The systemic reoxygenation injury produced by initiating cardiopulmonary bypass (CPB) in infants with cyanotic heart disease may be associated with cerebral dysfunction and injury. Increased protein S100 (S100) serum levels may indicate cerebral and blood brain barrier damage as well as inflammatory changes, therefore serving to quantify these changes. The present clinical study assessed S100 in cyanotic patients undergoing CPB with normoxic versus hyperoxic paO2 in acyanotic cases and in controls without CPB. METHODS: 43 patients with congenital heart disease aged 5 days to 15 years (mean 4.4 years) were enrolled consecutively and divided in four groups: (1) Cyanotic infants undergoing controlled normoxic reoxygenation on CPB (n = 12), (2) cyanotic infants undergoing uncontrolled hyperoxic reoxygenation on CPB (n = 9), (3) acyanotic infants operated with CPB (n = 16) and (4) patients operated without CPB (n = 6). Blood samples were collected after induction of anesthesia (A), up to 4 hours after surgery (B) and at postoperative day one (C). RESULTS: Preoperative S100 serum levels [microg/l] in all groups were below clinical relevance. S100 increased markedly after surgery in groups 1 and 2. Differences in postoperative S100 levels were significant between groups 1 (0.45 +/- 0.13) and 3 (0.35 +/- 0.09; p = 0.018), between groups 2 (1.41 +/- 0.47) and 3 (p = 0.01), and between groups 2 and 4 (0.29 +/- 0.09; p = 0.045). There were no significant differences in postoperative S100 levels (B) between groups 1 and 2 (p = 0.05), groups 1 and 4 (p = 0.05), or groups 3 and 4 (p = 0.93). CONCLUSION: Uncontrolled hyperoxic reoxygenation on CPB for surgical correction of congenital heart defects is associated with higher S100 levels in cyanotic infants as compared to acyanotic patients undergoing comparable operations.

Adolescent↗
PubMed1999

Effect of internal thoracic artery preparation on blood loss, lung function, and pain.

BACKGROUND: Postoperative blood loss, respiratory distress, and pain after coronary artery operation were assessed in a prospective, randomized, clinical study comparing two techniques of internal thoracic artery preparation. METHODS: In group A (n = 57) the internal thoracic artery was dissected with the entire surrounding connective tissue after opening the pleura, using routine lateral pleural drainage. In group B (n = 55) a venoarterial pedicle was prepared without surrounding muscle leaving the pleura intact. We assessed blood loss, clinical outcome, lung function, location, intensity, and quality of pain 6 days and 3 months after the operation. RESULTS: Significantly higher blood loss was observed in group A (A, 608+/-58 mL; B, 470+/-48 mL; p = 0.027). Forced expiratory volume in 1 second was significantly decreased in group A 6 days after surgery (A, 76.0%+/-1.6%; B, 83.2%+/-1.6%; p = 0.020). The forced expiratory volume in 1 second correlated to inspiratory vital capacity, which confirmed the advantage of the venoarterial technique (A, 0.771+/-0.021; B, 0.832+/-0.020; p = 0.003). Vital capacity was significantly higher in the venoarterial group at 3 months (A, 85.2%+/-2.1%; B, 98.5%+/-1.2%; p = 0.009), but not on postoperative day 6. The incidence of pleural effusion and atelectasis was significantly higher in group A (effusion: A, 52.6%; B, 23.6%; p = 0.002; atelectasis: A, 42.1%; B, 20.0%, p = 0.015). Sternal pain (A, 36.8%; B, 9.1%; p = 0.001) and suspenders pain (A, 33.3%; B, 7.3%; p = 0.001) occurred more often in group A. When using a multidimensional pain score, patients in group A experienced significantly sharper (6 days: A, 6.7+/-0.3; B, 3.3+/-0.2; p = 0.018; 3 months: A, 3.5+/-0.3; B, 1.4+/-0.3; p = 0.046) and more annoying pain (6 days: A, 7.6+/-0.2; B, 2.7+/-0.1; p = 0.036; 3 months: A, 6.6+/-0.3; B, 2.3+/-0.2; p = 0.040). CONCLUSIONS: These results demonstrate that the venoarterial preparation technique is superior to conventional internal thoracic artery preparation regarding postoperative blood loss, lung function, and pain.

Female↗
PubMed1999

Tracheostomy in cardiosurgical patients: surgical tracheostomy versus ciaglia and fantoni methods.

BACKGROUND: Patients requiring prolonged mechanical ventilation are not uncommon in a cardiosurgical intensive care unit. Elective tracheostomy is considered the airway treatment of choice in these patients. METHODS: To evaluate different techniques for tracheostomy, we prospectively investigated 120 patients who had conventional open (n = 40), minimally invasive percutaneous dilatational (n = 40), or translaryngeal (n = 40) tracheostomy techniques. The main areas of investigation included oxygenation index (partial pressure of arterial oxygen divided by fraction of inspired oxygen), complications, infection, and cost. RESULTS: The oxygenation index decreased in almost every patient, regardless of the technique used, but the extent of decrease was significantly lower in both minimally invasive techniques compared with the conventional method. Overall complication rate was 12.5% both in open tracheostomy and in percutaneous dilatational tracheostomy, whereas no complications occurred in translaryngeal tracheostomy procedures. Bacterial contamination of the tracheostomy site was found in 35% of the open tracheostomies, whereas no infection was seen in percutaneous dilatational or translaryngeal tracheostomies. In terms of costs, PDT ($506) and TLT ($362) were both much cheaper than open tracheostomy ($699). CONCLUSIONS: Percutaneous dilatational and translaryngeal tracheostomies are safe and cost-effective procedures that can be done easily at the patient's bedside and thus are attractive alternatives to conventional surgical tracheostomy in long-term airway access in a cardiosurgical intensive care unit.

Adult↗
PubMed1999

Synthetic protein treated versus heparin coated cardiopulmonary bypass surfaces: similar clinical results and minor biochemical differences.

OBJECTIVE: Complications associated with cardiopulmonary bypass (CPB) have gained more attention due to increased interest in coronary artery bypass grafting without CPB. The impact of heparin coating of CPB circuits has been discussed controversially. The present study examines if the treatment of the oxygenator surface with a synthetic protein may serve as an alternative to a completely heparin coated circuit. METHODS: Fifty-eight patients undergoing coronary artery bypass grafting with CPB were randomly assigned to completely heparin coated circuits or synthetic protein treated oxygenators in a double blind protocol, focussing on the inflammatory reaction resulting in membrane damage, coagulation changes and markers of cerebral injury or dysfunction. Treatment groups did not differ as to preoperative demographics, and intraoperative clinical data. Patients with any neurologic disease or risk factors for cerebral dysfunction were not included in the study. RESULTS: Postoperative clinical data did not differ between groups. Both surface treatments resulted in similar coagulation activation, hyperfibrinolysis and disseminated intravascular coagulation. Platelet count displayed a difference in favour of the heparin coated group (P = 0.029). Increased leukocyte activation reflected by rising myeloperoxidase concentrations on CPB was present in both synthetic protein and heparin coating groups. Interleukins 6 and 8 reacted similarly, but interleukin 8 increased significantly more (P = 0.0061) at the end of surgery in patients treated with protein treated oxygenators. The same pattern was observed for complement activation as determined by total complement complex (P = 0.006). Both surface changes resulted in moderately increased S-100B protein and neuron specific enolase, without difference between groups. Both markers did not reach concentrations associated with clinical manifestation of cerebral injury. CONCLUSIONS: These results in routine patients with short bypass time, imply that protein treated oxygenators are associated with a limited increase of biochemical markers similar to heparin coating. However, significantly lower interleukin 8 release and complement activation can be achieved by heparin coating. The protein treatment is a standard feature of the oxygenator examined in both groups. It is not associated with additional cost and therefore appropriate for use in routine patients.

Aged↗
PubMed1999

Patient selection for Port-Access multi vessel revascularization.

Minimally invasive multivessel revascularization is rarely performed due to the difficult exposure of the aorta as well as the complete coronary anatomy through a small thoracotomy. The Port-Access technique bears additional contraindications for this procedure, which limits its potential as compared with other approaches to 'less invasive surgery'. Our aim was to show the applicability of this surgical technique to a wide range of patients with coronary artery disease. In our initial experience with this method (31 patients), the quality of anastomoses, graft patency, and clinical outcome are good, and do not differ from standard multivessel coronary artery bypass grafting. Port-Access multivessel revascularization can be performed safely and is appropriate for a large patient population.

Cardiac Catheterization↗
PubMed1998

Neuropsychological changes after cardiopulmonary bypass for coronary artery bypass grafting.

BACKGROUND: An alarming incidence (1% to 83%) of neuropsychological dysfunction has been reported after operations using cardiopulmonary bypass (CPB). The present clinical study re-evaluates these complications with current CPB technology in a strictly selected low-risk group of coronary artery bypass (CABG) patients. METHODS: 76 CABG patients, without history of stroke or internal carotid artery stenosis, were examined before, 5 days after, and 2 months after surgery. A neuropsychological test battery was employed according to the "Statement of Consensus on Assessment of Neurobehavioral Outcomes after Cardiac Surgery". Tests include the Block Design Test (problem-solving strategies, recognition and analysis of forms), the Trail Making Test (cognitive achievement at speed), and the Digit Span Test (short-term memory and memory of figures). RESULTS: Both postoperative test scores were not significantly decreased as compared to preoperative values. In contrast, neuron specific enolase (NSE) and S100 b protein, biochemical markers of cerebral injury, increased markedly during and immediately after surgery (NSE preop.: 7.07 +/- 2.40 ng/ml, 1 h postop.: 13.64 +/- 4.50 ng/ml, p < 0.001; S100 b preop.: 0.04 +/- 0.07 ng/ml, after crossclamp: 0.90 +/- 0.69 ng/ml, p < 0.001). One patient displayed postoperative transitional syndrome, another patient suffered from transitory paresis and hypesthesia of the left arm, which disappeared during hospital stay. CONCLUSIONS: Biochemical markers demonstrate significant postoperative cerebral injury during and immediately after CPB. However, CPB for CABG does not lead to marked impairment of neuropsychological scores, and clinically relevant neurological findings were observed in one patient only.

Aged↗
PubMed1997

Heparin-induced thrombocytopenia type II: perioperative management using danaparoid in a coronary artery bypass patient with renal failure.

An 84-year-old patient with heparin-induced thrombocytopenia (HIT), global cardiac decompensation, and acute renal failure underwent a cardiosurgical intervention using an extracorporeal circuit. For systemic anticoagulation danaparoid (Orgaran) was applied as a heparin substitute preoperatively and maintained for systemic anticoagulation during ECC despite it being eliminated by the kidney. The postoperative recovery was prolonged due to bleeding complications. During cardiopulmonary bypass (216 min) the target level of anti-factor Xa was 1.5 UI/ml. This required continuous infusion and an occasional bolus of danaparoid. Coagulation in the extracorporeal circuit was observed twice at plasma levels below 1.4 IU/ml. There were no thromboembolic or neurologic events. We did not retransfuse blood from the extracorporeal circuit or the cardiotomy reservoir after bypass, but because elimination of danaparoid was impaired in this patient and there is no neutraliser available antifactor Xa postoperatively exceeded 0.6 IU/ml for 30 hours. Diffuse bleeding with tamponade resulted. Weaning the patient from the respirator was achieved 12 hours after the last re-exploration. From the 4th postoperative day 750 IU of danaparoid were administered twice daily subcutaneously for thrombosis prevention. On the 6th postoperative day discharge from the ICU was possible. We conclude that the application of danaparoid for cardiopulmonary bypass in patients suffering from acute renal failure may be complicated by hemorrhage.

Acute Kidney Injury↗
PubMed1997

Influence of case scheduling on outcome in cardiac surgery.

OBJECTIVE: Whether scheduling of patients for cardiac surgery as dictated by the availability of cardiopulmonary machines (CPBM) may influence postsurgical outcome, thought not to be an issue in the past, is unknown. EXPERIMENTAL DESIGN AND SETTING: Cardiac surgical outcomes were compared between two consecutive 12 months intervals surrounding the acquisition of a second CPBM by our department in a general hospital. PATIENTS: Patients in Group A (n=416) underwent surgery when only 1 CPBM was available (February 1990-January 1991) and in Group B (n=603) when 2 CPBM were used (February 1991 to January 1992). A cohort, Group C, consisted of patients (n=73), found only in Group A, scheduled as a 3rd and 4th operative case in the same day. RESULTS: There were no significant differences in demographic and clinical characteristics, the duration of ICU stay or hospital discharge between groups A and B. The surgical or technical staff did not change, and the nurse to patient ratio remained constant. Median total bypass time was significantly greater in Group B (80 vs 73 min in Group A, p<0.05), but the frequency of mortality within the first 14 postoperative days was nevertheless lower in Group B than in Group A (3.3% vs 4.6%, respectively, p<0.05). Recurrent myocardial infarction, postoperative bleeding, arrhythmia, pulmonary embolism, acute renal failure, and duodenal ulcer were also significantly higher in Group A compared to Group B (p<0.05). The excess in postoperative complications could be attributed mainly to Group C. Overall, the relative risk for morbidity and mortality decreased when a second CPBM was implemented (p<0.001). CONCLUSIONS. Postoperative complications in our unit were significantly reduced by acquisition of a second CPBM permitting two cases to be started concomitantly early in the day. This data may be valuable to guide decision analysis in departments which need to expand resources in order to cope with the demand of expanding clinical case load.

Aged↗