Reexploration for bleeding is a risk factor for adverse outcomes after cardiac operations

OBJECTIVE: Although previous studies have included early reexploration for bleeding as a risk factor in analyzing adverse outcomes after cardiac operations, reexploration for bleeding has not been systematically examined as a multivariate risk factor for increased morbidity and mortality after cardiac surgery. Furthermore, multivariate predictors of the need for reexploration have not been identified. Accordingly, we performed a retrospective analysis of 6100 patients requiring cardiopulmonary bypass from January 1, 1986, to December 31, 1993. METHODS: Eighty-five patients who had ventricular assist devices were excluded from further analysis because of the prevalence of bleeding and the significant morbidity and mortality associated with placement of a ventricular assist device, unrelated to reexploration. In the remaining 6015 patients, potential adverse outcomes analyzed included operative mortality, mediastinitis, stroke, renal failure, adult respiratory distress syndrome, prolonged mechanical ventilation, sepsis, atrial arrhythmias, and ventricular arrhythmias. To control for the confounding effects of other risk factors, we performed a multivariate logistic regression analysis. Potential covariates considered in the logistic model included age, sex, race, history of reoperation, urgency of the operation, congestive heart failure, prior myocardial infarction, renal failure, diabetes, hypertension, chronic obstructive pulmonary disease or stroke, and the bypass and crossclamp time. RESULTS: The overall incidence of reexploration was 4.2% (253/6015). Four independent risk factors--increased patient age (p < 0.001), preoperative renal insufficiency (p = 0.02), operation other than coronary bypass (p < 0.001), and prolonged bypass time (p = 0.0.3)--were identified as predictors of the need for reexploration. The preoperative use of aspirin, heparin, or thrombolytic agents and the bleeding time were not identified as predictors. Reexploration for bleeding was identified as a strong independent risk factor for operative mortality (p = 0.005), renal failure (p < 0.0001), prolonged mechanical ventilation (p < 0.0001), adult respiratory distress syndrome (p = 0.03), sepsis (p < 0.0001), and atrial arrhythmias (p = 0.006). CONCLUSION: These data indicate that meticulous attention to surgical hemostasis and possibly application of recently developed modalities designed to facilitate perioperative correction of coagulopathy could improve outcomes after cardiac operations.     

Intravenous diltiazem and acute renal failure after cardiac operations

BACKGROUND: Perioperative administration of intravenous diltiazem to patients undergoing cardiac procedures has been shown to decrease the incidence of ischemia and arrhythmias. However, after adopting this practice in our cardiac surgery program, we perceived an increased incidence of postoperative renal dysfunction. METHODS: A directed record review of postoperative renal function was conducted for consecutive patients undergoing cardiac operation for the time periods before and after adoption of prophylactic intravenous diltiazem (0.1 mg.kg-1.h-1 for 24 hours). The two groups were compared using chi 2 and two-sample t tests. The risk of development of postoperative renal failure was modeled with logistic regression. RESULTS: Diltiazem-treated patients (n = 271) were similar to the control patients (n = 143) in terms of age (64 versus 61 years; p = 0.14), ejection fraction (0.46 versus 0.47; p = 0.61), baseline serum creatinine level (1.2 versus 1.1 mg/dL; p = 0.27), prevalence of comorbid conditions, and surgical characteristics. The prevalence of left main coronary artery disease was lower in the diltiazem group than the control group (39% versus 52%; p = 0.01). During the 7-day postoperative period, the average peak serum creatinine level was higher in the diltiazem group (1.7 +/- 0.9 mg/dL; mean +/- 1 standard deviation) than the control group (1.5 +/- 0.5 mg/dL; p = 0.003). The incidence of acute renal failure requiring dialysis was 4.4% in the diltiazem group versus 0.7% in the control group (p = 0.04). There was no difference in length of hospitalization or mortality. The risk of acute renal failure was strongly associated with intravenous diltiazem (adjusted odds ratio [AOR] 6.3; p = 0.08), age (AOR 2.5 per 10 years; p = 0.07), baseline serum creatinine (AOR 4.8 per 1 mg/dL; p = 0.02), the presence of left main coronary disease (AOR 5.3; p = 0.02), and the presence of cerebrovascular disease (AOR 4.5; p = 0.05). CONCLUSIONS: Our retrospective analysis suggests that prophylactic use of intravenous diltiazem in patients undergoing cardiac operations was associated with increased renal dysfunction. Further studies of the risk and benefits of intravenous diltiazem in this setting should be undertaken.     

Infectious mediastinitis after cardiac operations: computed tomographic findings

BACKGROUND: Infectious mediastinitis after cardiac operations is of great concern to cardiac surgeons because of its poor prognosis. Prompt surgical interventions such as debridement and irrigation are the key to treatment of infectious mediastinitis. METHODS: We surveyed retrospectively the cases of 722 consecutive cardiac surgery patients at our hospital. Mediastinitis developed in 21 patients after the cardiac operation. We performed computed tomography in 11 of these patients before resternotomy and in 10 patients as the control 2 to 3 weeks after the cardiac operation. RESULTS: Mediastinal soft tissue swelling was seen in 7 patients, bilateral pleural effusion was found in 9 patients, sternal dehiscence or sternal erosion was observed in 8 patients, and subcutaneous fluid accumulation was found in 7 of the mediastinitis group. Unilateral pleural effusion was seen in 6 and bilateral effusion in 1, and mediastinal soft tissue swelling was seen in 1 patient of the control group. CONCLUSIONS: Our study showed that mediastinal soft tissue mass combined with bilateral pleural effusion can be a characteristic computed tomography finding in poststernotomy infectious mediastinitis, and that chest computed tomography is more sensitive to detecting sternal dehiscence, sternal erosion, and subcutaneous fluid accumulation.     

Predicting the occurrence of adverse events after coronary artery bypass surgery

Approximately 15% of patients with mitral valve disease will experience left atrial thrombosis and its consequences. The etiology and diagnosis of left atrial thrombosis are reviewed, stressing the importance of blood stagnation as the most important etiologic factor. Atrial fibrillation, a left atrial diameter greater than 60 mm and absence of significant mitral regurgitation are predictors of left atrial thrombosis in mitral stenosis. Left atrial thrombus can be detected in 50% of patients with all three factors; all influence blood stagnation. Smoke-like echoes in the left atrium, detected by echocardiography, provide a semi-quantitative assessment of left atrial blood stagnation. The incidence of thrombi in patients with well marked smoke-like echoes is 60%, while in those without this echocardiographic finding it is only 9%. Smoke-like echoes provide an early warning system of conditions in the left atrium likely to lead to thrombosis unless the patient is anticoagulated.     

Rapid safe central venous access in children and adults undergoing open cardiac operations

A technique is described for percutaneous placement of central venous catheters under direct vision in children and adults undergoing open heart operations. The method is reliable, rapid, and safe, and avoids blind attempts at obtaining vascular access.     

Hyperamylasemia after cardiac surgery in infants and children

OBJECTIVE: This study was conducted to clarify the incidence of hyperamylasemia after cardiac surgery in infants and children. DESIGN AND PATIENTS: 186 infants and children operated on at Children's Hospital. Helsinki, during an 11-month period were enrolled in the study. Serum samples were taken before and on 3 consecutive days after cardiac surgery at the intensive care unit and before discharge from the hospital. MEASUREMENTS: We measured serum total amylase and serum pancreatic amylase with two different assays (1) reduction of salivary amylase from total amylase activity and (2) measurement of mass concentration with monoclonal antibodies. RESULTS: Preoperative values for both total amylase and pancreatic isoenzymes were strongly age-related. At least one of the three tests showed postoperative hyperamylasemia (> +/- 2 SD above starting values of the age group and maximal value > 3 times the individual starting value) in 64/186 (34%) patients. 22/186 (12%) patients had abnormal results in all assays. A more than tenfold rise in pancreatic amylase, suggesting pancreatitis, was found in 14 patients (8%). Mortality was 21% in this subgroup, but 5% in the rest of the patients. Hyperamylasemia was more common after 1 year of age, and after open-heart surgery, especially homograft implantation or cardiac transplantation. CONCLUSIONS: Hyperamylasemia is a common finding after cardiac surgery in pediatric patients. Amylase isoenzyme measurements are needed for clinical decision making. Age-group-related reference values are mandatory for the right interpretation of amylase values.     

Shed mediastinal blood transfusion after cardiac operations: a cost-effectiveness analysis

BACKGROUND: Cardiac surgical patients consume a significant fraction of the annual volume of allogeneic blood transfused. Scavenged autologous blood may serve as a cost-effective means of conserving donated blood and avoiding transfusion-related complications. METHODS: This study examines 834 patients after cardiac operations at the University of Alabama Hospital. Data were collected on patients receiving unwashed, filtered, autologous transfusions from shed mediastinal drainage and those receiving allogeneic transfusions. The data were incorporated into clinical decision models; confidence intervals for parameters were estimated by bootstrapping sample statistics. Costs were estimated for transfusing both allogeneic and autologous blood. RESULTS: The study found a 54% reduction in transfusion risk or a mean reduction of 1.41 allogeneic units per case (95% confidence interval, 1.04 to 1.79 units). The process saved between $49 and $62 per case. CONCLUSIONS: The use of autologous blood has the potential to significantly reduce the costs and risks associated with transfusing allogeneic blood after cardiac operations.     

Risk factors for clinically important adverse events after protamine administration following cardiopulmonary bypass

OBJECTIVES: The purpose of this study was to determine risk factors for adverse events following protamine administration after cardiopulmonary bypass. BACKGROUND: Intravenous protamine administration is associated with a risk of severe systemic reactions. However, risk factors for these events have not been well delineated, thus hampering development of preventive strategies. METHODS: A case-control study nested within a cohort of consecutive patients undergoing surgery requiring cardiopulmonary bypass was performed. The primary case definition included those events (pulmonary hypertensive and systemic hypotensive) occurring within 10 min of protamine administration in the absence of other measurable causes of hemodynamic compromise. RESULTS: Comparing the 53 cases to the 223 control subjects, three risk factors were independently associated with events (multivariable odds ratio [95% confidence interval]): neutral protamine Hagedorn insulin use (8.18 [2.08, 32.2]); fish allergy (24.5 [1.24, 482.3]), and a history of nonprotamine medication allergy (2.97 [1.25, 7.07]). These risk factors demonstrated an increasingly strong association with progressively more specific case definitions. An estimated 39% of cardiopulmonary bypass patients had one or more of these risk factors. Prior intravenous protamine, central venous pressure prior to protamine, preoperative ejection fraction and the need for inotropes when coming off bypass did not exhibit statistically significant associations with events (all p > 0.15). Prior protamine allergy was associated specifically with an increased risk of pulmonary hypertension (multivariable odds ratio 189; 95% confidence interval 13, 2,856). CONCLUSIONS: Immunologic factors are important in predisposing individuals to protamine reactions, and a substantial proportion of patients are at considerably increased risk Strategies to reduce the risk of protamine-associated events are needed.     

Early events in erythropoietin-induced signaling

The cloning of the erythropoietin receptor (EpoR) in 1989 has allowed very rapid progress in our understanding of the early intracellular events that may be triggered by erythropoietin (Epo) in erythroid progenitor cells. From studies carried out primarily with cell lines expressing exogenous wild-type and mutant EpoRs, it appears that the activated EpoR is capable of triggering many of the same cascades that are utilized by receptors possessing endogenous tyrosine kinase domains. The major challenge over the next decade lies in seeing if these same signaling pathways are also utilized by normal Epo-responsive erythroid progenitors, discriminating between proliferation and differentiation inducing events in these cells, and determining whether various hematologic disorders can be attributed to aberrations in these signaling pathways.     

The benefits of active rewarming after cardiac operations: a randomized prospective trial

Studies were carried out to observe the species composition of mosquitos and to determine the vectors responsible for the transmission of filariasis in Grik, Perak, Malaysia. A total of 2,155 mosquitos belonging to 7 genera and 30 species were collected. Anopheles donaldi comprised 24.1% of the collection. Twelve out of 519 An. donaldi were infected with L3 larvae of Brugia malayi. The peak biting time was around 23.00-24.00 hours. The infective bites per month ranged from 0 to 6.3.     

Risks of repeat sternotomy in pediatric cardiac operations

BACKGROUND: Repeat sternotomy has been associated with increased perioperative risks. METHODS: We reviewed 165 patients undergoing 192 repeat sternotomies between January 1985 and January 1997 (group 1) and a control group of 184 patients (group 2). The operations in group 1 were valve procedures in 94 patients, Fontan procedure in 46, ventricular septal defect closure in 10, pulmonary arterioplasty in 17, and others in 25; in group 2 ventricular or atrial septal defect closure in 120 patients, tetralogy of Fallot repair in 26, valve procedures in 16, bidirectional Glenn anastomosis in 7, repair of transposition of the great arteries in 7, pulmonary arterioplasty in 4, and others in 4. RESULTS: The hospital mortality was 2.6% in group 1 and 3.8% in group 2. Cardiac laceration occurred in 10 of 192 patients (5.2%), requiring emergent femorofemoral bypass in 6 patients. Two patients sustained an air embolism that was successfully treated with a hyperbaric chamber. Median total blood loss and requirements were not significantly different between the two groups. The length of stay in the intensive care unit and in the hospital were 4 days (range, 1 to 80 days) and 11 days (range, 1 to 135 days) in group 1, and 2 days (range, 1 to 87 days) and 7 days (range, 1 to 131 days) in group 2 (p < 0.02 and p < 0.002, respectively). The rate of complications was not significantly different in group 1 versus group 2. Overall survival was 97% (group 1) and 95% (group 2) at 120 months' follow-up (not significant). CONCLUSIONS: With careful surgical technique and judicious use of femorofemoral bypass, the risk of repeat sternotomy is minimized.     

Corrective operations in ureterocele in children

The authors analyze their experience in the treatment of 59 children aged 3 months--14 years with ureterocele of the single (22 patients) and double ureter (37 patients). Examination and surgical data showed that ureterocele in the operated on children was congenital and became a component of a complicated malformation of the distal ureter. Structural changes varied from minimal to total dysplasia reflected in the degree of the ureteral dilatation. These changes were characteristic for both normal and double ureters and served the base for treatment policy decision. In normal megaureter the authors performed resection of the distal ureter as well as ureterocele, modelling and neoplantation of the proximal segment according to the antireflux technique. Minor dilatation of the pelvic ureter (up to 1.0-1.5 cm dependent on the patient's age) indicated that structural alterations of its wall are confined to the submucosal segment. In view of this, surgical intervention involved only endovesicular electroperforation of ureterocele. The policy in the double ureter ureterocele was based on the same criteria.     

Upper extremity vascular access for continuous arteriovenous hemofiltration and dialysis after cardiac operations

BACKGROUND: There is increasing interest in the use of continuous arteriovenous hemofiltration/dialysis for treatment of profound renal failure after cardiovascular operations. Vascular access for this is usually accomplished by percutaneous cannulation of the femoral artery and vein, with the inherent risks of vascular trauma, patient immobilization, hemorrhage, or infectious complications. METHODS: Fifteen (0.36%) of 4,166 patients receiving cardiovascular surgical procedures sustained postoperative renal failure requiring treatment with continuous arteriovenous hemofiltration/dialysis. Each patient had creation of acute arteriovenous forearm access using a modified Allen-Brown shunt. Shunts were monitored continuously for hemorrhage, malfunction, infection, and thrombus, and were explanted when no longer required. RESULTS: Sixteen shunts were implanted in 15 patients over the 41-month period. All shunts functioned satisfactorily, with the duration of implantation ranging from 1 to 64 days. There were no infectious or hemorrhagic complications. CONCLUSIONS: The acute creation of a simple forearm shunt for postoperative continuous arteriovenous hemo-filtration/dialysis is preferred over femoral arterial and venous cannulation because it can be constructed rapidly and easily in the operating room or at the bedside, has a low complication rate, is available for immediate use, may be left in place indefinitely, does not interfere with patient mobilization or ambulation, and is easily removed.     

Addition of a thiazide: an effective remedy for furosemide resistance after cardiac operations

BACKGROUND: The frequent use of diuretic drugs in cardiac surgical practice contrasts with the lack of documentation regarding diuretic treatment in this setting. The aims of this study were to delineate the need for diuretic drugs in adult cardiac surgical practice and to evaluate the impact of adding a combination of 50 mg hydrochlorothiazide and 5 mg amiloride orally to patients responding poorly to furosemide. METHODS: Two hundred ten consecutive patients, 159 undergoing coronary artery bypass grafting procedures and 51 having valve operations, were studied. RESULTS: Seventy-seven patients received large doses of furosemide (> or = 80 mg/24 h) at some time during the postoperative course, and of these 20 responded poorly to furosemide (weight loss 0.3 +/- 0.2 kg) despite considerable fluid retention. The addition of hydrochlorothiazide and amiloride provided a prompt and effective remedy to relative furosemide resistance. Average weight loss was 2.3 +/- 0.2 kg (p < 0.01 compared with response to furosemide) and average diuresis was 2,949 +/- 156 mL in the following 24 hours. CONCLUSIONS: Relative furosemide resistance is common after cardiac operations. Thiazides, although they are mild diuretic agents, may serve as useful adjuncts in this setting.