Perioperative serum levels of tumour-necrosis-factor alpha (TNF-alpha), IL-1 beta, IL-6, IL-10 and soluble IL-2 receptor in patients undergoing cardiac surgery with cardiopulmonary bypass without and with correction for haemodilution

Cardiac surgery with cardiopulmonary bypass (CPB) leads to a systemic inflammatory response with secretion of cytokines. Alterations in the serum concentrations of cytokines have important prognostic significance. Reports on cytokine release during cardiac surgery with CPB have yielded conflicting results. Haemodilution occurs with the onset of CPB resulting in large fluid shifts during the perioperative course of cardiac procedures. In the present study we compare the perioperative course of serum concentrations of TNF-alpha, IL-1beta, IL-6, IL-10 and sIL-2R with and without correction for haemodilution in patients undergoing coronary artery bypass grafting (CABG) surgery. Twenty male patients undergoing elective CABG surgery with CPB and general anaesthesia using a balanced technique with sufentanil, isoflurane and midazolam were enrolled into the study. Serum levels of TNF-alpha, IL-1beta, IL-6, IL-10 and sIL-2R were measured using commercially available ELISA kits. Simultaneous haematocrit values were obtained at all sample times. Statistical analysis was performed by non-parametric analysis of variance and t-tests for data corrected for haemodilution and data that were not corrected for haemodilution. Adjusted significance level was P < 0.01. Intra-operatively, up to the second post-operative day PCV values were significantly decreased compared with preoperative values. Cytokine measurements not corrected for haemodilution were significantly lower than the corrected values. The perioperative haemodilution and decrease in PCV may lead to an underestimation of the cytokine secretion in post-operative patients. We conclude that cytokine measurements were significantly influenced by the perioperative haemodilution and the subsequent decrease in PCV and may in part account for the varying results reported in the literature regarding cytokine release in patients undergoing CABG surgery.

Pulmonary surfactant composition early in development of acute lung injury after cardiopulmonary bypass: prophylactic use of surfactant therapy

Cardiopulmonary bypass surgery (CPB) causes lung injury and at least 2% of adult patients and more children develop the most severe from acute respiratory distress syndrome (ARDS). Pulmonary surfactant deficiency contributes to the pathogenesis of ARDS. It has been proposed that surfactant therapy immediately after CPB might arrest progression to ARDS. However, many patients develop only mild lung injury after CPB. Thus early markers are needed to identify those patients at highest risk to guide selection for treatment. The aim of this study was to determine whether changes in surfactant phospholipids occur, and reflect severity of lung injury within the first few hours after bypass. Because of the relatively low incidence of ARDS in adult patients, this study was conducted using young pigs highly susceptible to bypass-induced lung injury. Eight pigs were given 2 hours bypass. Six controls underwent 'sham' bypass. At 3 h after bypass pulmonary vascular endothelial permeability was assessed by transcapillary leakage of radiolabelled transferrin. A 4 hour broncho-alveolar lavage (BAL) was used to assess intra-alveolar levels of surfactant, inflammatory cells and oedema protein. Bypass caused falls in arterial oxygenation and lung compliance (P < 0.01), but at this early stage in progression of lung injury BAL surfactant phospholipid and albumin levels were within the control range indicating that the alveolar epithelium had not yet suffered major damage. The main abnormalities were increases in vascular endothelial permeability (P < 0.01), BAL neutrophils (P < 0.01), total protein and sphingomyelin (SM) (P < 0.05). Lung histology showed that the main damage was interstitial oedema located around the bronchioles and their associated vessels. A single instilled dose of surfactant phospholipids in 5 animals caused excess in vivo supplementation and did not reduce the early pathophysiologic changes. Our findings suggest that surfactant phospholipid deficiency does not make a major contribution in the initial stages of lung injury after CPB, and that excessive phospholipid supplementation at this stage can be deleterious.

Complete atrioventricular canal defect: surgical considerations

Complete atrioventricular canal defect is a serious and complex cardiac anomaly that is frequently associated with other congenital cardiac defects. Its natural course is ultimately fatal; 80% of children born with this defect will die within 2 years. Long-term medical therapy for complete atrioventricular canal defect is ineffective; therefore, either palliative or curative surgery is required. The risk of corrective surgery for this defect in infancy has steadily decreased because of improvements in surgical techniques, anesthesia, and postoperative management. This report describes our current surgical technique for primary corrective repair of complete atrioventricular canal defect, with a review of recent results of this procedure in 34 patients.

A new cannula and an old method for aortic cannulation in infants

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Successful treatment of acute postoperative right heart failure with low-dose prostaglandin e(1) and assisted circulation

Immediately after undergoing emergency mitral valve replacement, a 60-year-old woman suffered acute postoperative right heart failure and could not be weaned from cardiopulmonary bypass, despite treatment with multiple drugs. Circulatory assistance was instituted by means of femoro-femoral bypass with a roller pump and a hollow-fiber oxygenator; inotropic drugs and drugs aimed at reducing pulmonary vascular resistance (nitroprusside, moxaverine, and isoproterenol) were also given. The patient's systolic pulmonary pressure underwent a progressive decrease, but her systolic systemic pressure remained below 60 mmHg until 8.5 hours after aortic clamp release, when we were able to begin an infusion of prostaglandin E(1), a drug not readily available in our hospital. Fifteen minutes after the infusion was started, at 5 ng/kg/min, the patient's systolic systemic pressure reached 85 mmHg and her systolic pulmonary pressure decreased to 55 mmHg. During the next 2 hours, epinephrine treatment was discontinued, and the assisted circulatory flow was reduced to 0.5 L/min/m(2), while the PGE(1) infusion was increased to 10 ng/kg/min. Assisted circulation was soon discontinued, and the patient's hemodynamic condition remained stable.

Primary malignant fibrous histiocytoma of the right ventricle and main pulmonary trunk with a review of the literature

We report the case of a 76-year-old man with a malignant fibrous histiocytoma of the right ventricle and main pulmonary trunk, diagnosed through echocardiography and catheterization. Extensive resection of the right ventricular outflow tract, pulmonary valve apparatus, and main pulmonary trunk was performed, and the defect was repaired with a valveless ventriculo-pulmonary Dacron graft. The patient recovered uneventfully, and was doing well 18 months after surgery. To our knowledge, this is only the 15th case of primary malignant fibrous histiocytoma of the heart that has been documented in the literature since histologic criteria and cases were published in 1977-78, and the 2nd such case of a primary tumor that has arisen in a right cardiac chamber. The case is presented in detail, along with a review of the literature since 1978.

A comparison of flat-sheet and hollow-fiber membrane oxygenators: the Shiley M-2000 vs. the Bentley BOS-CM 40

To compare new flat-sheet and hollow-fiber membrane oxygenators for use in cardiopulmonary bypass, we randomly divided 40 coronary artery surgery patients into 2 groups of 20 patients each. The Shiley M-2000 flat-sheet membrane oxygenator was used in 1 group, and the Bentley BOS-CM40 hollow-fiber membrane oxygenator was used in the other group. Both oxygenators allowed for adequate transfer of oxygen and carbon dioxide. At the end of perfusion, the platelet counts were significantly lower and the arterial pH significantly higher in the Shiley group than in the Bentley group. The other hematologic parameters, as well as postoperative blood losses, were similar in the 2 groups, but were also similar to those reported earlier with respect to bubble oxygenators. On the basis of these results, we conclude that, for routine short-term perfusion, these new membrane oxygenator models, while marginally different from one another, offer no real advantage over bubble models.

A prospective study of the clinical benefits of prostacyclin in 554 cardiopulmonary bypass procedures

Abnormal bleeding after cardiopulmonary bypass (CPB) may result from incomplete neutralization of heparin, increased fibrinolytic activity, consumption of coagulation factors, or from a reduction in the number of circulating platelets together with impairment of platelet function. Although researchers have reason to believe that hemostasis after CPB could be improved with prostacyclin (PGI(2)), a potent inhibitor of platelet aggregation, the drug's clear-cut benefits in this respect have not yet been confirmed. After conducting an initial study concerning the fate of platelets during CPB, in which we determined that PGI(2) had a protective effect, we investigated the effects of PGI(2) infusion during CPB on postoperative blood loss in 554 open-heart surgery patients, 200 of whom underwent valve replacement, 200 of whom had coronary artery bypass grafting (CABG), and 154 of whom underwent repeat valve replacement or CABG. The patients were divided into 2 groups: 277 patients (the study group) received both heparin and PGI(2) during CPB, whereas the remaining 277 patients (the control group) were given heparin alone. Of the patients who underwent surgery for the first time, those treated with PGI(2) had a reduced mean blood loss (p < 0.05 only in CABG patients) in comparison with those who received heparin alone. Of the patients who underwent redo operations, those who received PGI(2) had a nonsignificant tendency toward reduced blood loss. The mean difference in blood loss between the study group and the control group had no clinical relevance, however, because it was less than the smallest practical unit of measurement (i.e., 1 unit of blood).

Complement activation during cardiac and thoracic vascular operations

To study complement activation, we evaluated nine patients who underwent cardiac operations requiring cardiopulmonary bypass (CPB) and nine other patients who underwent thoracic vascular operations without CPB. Concentration of C3, as measured by radioimmunoassay, was used as an indicator of complement activation (C3a is a complement-degradation product). In the CPB patients, the C3a level increased tenfold (from baseline value) after the onset of bypass, and continued to increase during bypass. Protamine produced an additional twofold increase in the C3a value, to a peak of 5461 +/- 1360 ng/ml. By 12 hours after surgery, the C3a level had decreased to normal (400 ng/ml). In the non-CPB patients, C3a remained at baseline levels until the administration of protamine, which caused a tenfold increase to a peak of 2281 +/- 293 ng/ml; C3a levels returned to normal 6 hours after operation. The peak postprotamine C3a levels were significantly higher (p < 0.01) in the CPB group than in the non-CPB group. This finding was due to the fact that, during CPB, complement activation occurs via the alternative pathway; the administration of protamine then causes additional activation via the classical pathway. During thoracic vascular operations, however, complement activation occurs only in response to protamine, via the classical pathway.

Lindbergh and the biological sciences (a personal reminiscence)

In 1929 Charles Lindbergh became interested in the development of a heart-bypass pump to enable open-heart surgery, and was introduced to Alexis Carrel. Carrel persuaded Lindbergh to work instead on a perfusion system for the culture of whole organs outside the body, and by 1934-when I met Lindbergh in Copenhagen-he already had developed a pump with floating glass valves that allowed precise regulation of perfusion pressure and rate. I joined Lindbergh and Carrel at the Rockefeller Institute to work on organ culture, using the pump. My subsequent contact with Lindbergh came at Columbia, where I experimented with hemocyanin as a blood substitute, and (much later) at Huntington Medical Research Institutes, where I found his pump useful in the study of cholesterol uptake by arteries.

Development of the roller pump for use in the cardiopulmonary bypass circuit

In 1937, John Gibbon proposed his concept of extracorporeal circulation as an aid to cardiac surgery. Subsequently, a number of different types of pumps were tried in the extracorporeal circuit. Today, the pump used most often is a positive displacement twin roller pump, originally patented by Porter and Bradley in 1855. The rotary pump has undergone some minor modifications prior to its use in clinical cardiopulmonary bypass. Cardiovascular surgeons owe much to Porter and Bradley for an invention that has proved both efficient and effective for cardiopulmonary bypass and has allowed operations on an open heart in a relatively dry, bloodless field.

Postcardiotomy right ventricular failure: experience with pulmonary arterial balloon counterpulsation and pulmonary arterial venting

From 1981 through 1985, 3,057 patients underwent cardiac operations using cardiopulmonary bypass (CPB) at our institution. When we reviewed these cases, we found that in ten cases (0.32%) right ventricular or biventricular failure had prevented weaning from CPB. All ten patients were also refractory to pharmacologic intervention and to systemic intraaortic balloon pumping. Two patients had isolated right ventricular failure, and the other eight had biventricular failure. Four patients had had previous pulmonary hypertension. Of the ten patients who could not be weaned, three were treated with pulmonary arterial balloon counterpulsation (PABC), and seven underwent pulmonary arterial venting (PAV). Procedures performed concomitantly with PABC included left heart bypass in one case and creation of an atrial septal defect in another case. All of the PAV group underwent concomitant intraaortic balloon pumping. One PABC patient and four PAV patients could be weaned from CPB. All who were treated with PABC eventually died, but there are three long-term survivors in the PAV group. In light of this study, biventricular unloading with PAV appears to be a valid method of treating right ventricular or biventricular failure.

Scanning electron microscopy of circulating platelets reveals new aspects of platelet alteration during cardiopulmonary bypass operations

Seventeen male patients undergoing cardiopulmonary bypass (CPBP) surgery for aorto-coronary bypass grafting were investigated by scanning electron microscopy (SEM) for alterations of the surface morphology of circulating platelets. An initial decline in the percentage of unactivated smooth discocytes (SD) to 87 +/- 12% was found after thoracotomy. Three minutes after the onset of CPBP, the percentage of SD had dropped drastically to 59 +/- 13%, and by the 8th minute of CPBP it had dropped to its lowest point (49 +/- 19%). On the other hand, the percentage of shape-changed platelets (SC) increased to 17 +/- 9% after 3 minutes, and the percentage of pseudopod discocytes (PD) to 25 +/- 13% after 8 minutes. Surprisingly, a remarkable recovery of platelet morphology could be observed after even 15 minutes of CPBP, and by the end of bypass 78 +/- 15% of the circulating platelets had regained the smooth discoid (SD) appearance of unactivated platelets. We conclude that this recovery of platelet morphology is due to an increasing insensitivity of the platelets to activating stimuli during the course of CPBP. Our study provides evidence that the only major platelet activation occurs during the first minutes of CPBP, and that CPBP-caused platelet activation is much less pronounced than generally believed.

Effect of dextrose-crystalloid priming solution on fluid requirements and urine output during cardiopulmonary bypass

We examined the influence of the addition of dextrose to crystalloid cardiopulmonary bypass priming solution. Ten patients received only lactated Ringer's solution during the perioperative period and as their cardiopulmonary bypass priming solution, while ten others, managed identically in all other respects, received only 5% dextrose in lactated Ringer's solution (D5LR). During cardiopulmonary bypass, patients who did not receive glucose required more supplementary fluid (20.0 vs 2.2 ml Kg(-1) hr(-1)) to maintain adequate flow rates, but made less urine (1.1 vs 2.8 ml Kg(-1)) than their glucose-treated cohorts. Postoperative hemoglobin was significantly lower in the group receiving lactated Ringer's solution (-14%) but not in the patients receiving D5LR (-6%). We conclude that the addition of dextrose to a crystalloid priming solution decreases intraoperative fluid requirements and helps restore precardiopulmonary bypass hemoglobin without the need for diuretics or blood products.