Norman J Manley

Effect of surface coating on platelet count drop during cardiopulmonary bypass

This study was designed to investigate the effect of surface coating on platelet count drop during cardiopulmonary bypass (CPB). Sixty patients undergoing open-heart surgery were randomly divided into three groups each receiving a different type of coated hollow-fiber membrane oxygenator. The patients were given either an uncoated oxygenator (noncoated group), an oxygenator coated with Carmeda® (Carmeda group) or an uncoated oxygenator with albumin in the priming solution (albumin group). Comparisons were made in platelet count pre-CPB, on bypass (15-25 min) and during the warming period. Calculations were used to account for the effect of hemodilution. The albumin group had significantly lower platelet count drops (-4.8 ± 7.1%) than the Carmeda group (11.0 ± 8.3%) and the noncoated group (20.3 ± 14.5%). Carmeda surface coating demonstrated some beneficial effects, but to a lesser degree than the albumin.

Obstruction of the True Lumen during Retrograde Perfusion of Type I Aortic Dissections: A Simplified Solution

Retrograde perfusion of the false lumen in cases of type I dissection of the thoracic aorta may not permit reperfusion of the coronary arteries when the aortic cross-clamp is removed. We have employed a Y connector between the coronary perfusion outlet of the oxygenator and cardioplegia delivery system. This allows reperfusion of the coronary arteries through the ascending aortic graft. As cardiopulmonary bypass is discontinued, the true aortic lumen is reexpanded and the false lumen collapsed by forward flow of blood from the heart. The successful use of this system is described.

Albumin in the cardiopulmonary bypass prime: how little is enough?:

Previous studies have demonstrated high transoxygenator pressures with noncoated hollow-fiber membrane oxygenators. These reports have been associated with dramatic platelet count drops during cardiopulmonary bypass (CPB). It has also been shown that adding human albumin to the prime of the bypass circuit reduces, if not eliminates, these problems. This study was conducted to determine what is the smallest amount of albumin added to the prime that will still display its protective effects. Eighty patients undergoing nonemergency open-heart surgery were randomly divided into four groups. Groups I and II received the Sarns Turbo 440 oxygenator with 0.0375 g of albumin/100 ml of prime and 0.125 g of albumin/100 ml of prime, respectively, added to the pump prime. Groups III and IV received the Medtronic Maxima-PRF oxygenator with 0.0375 g of albumin/100 ml of prime and 0.125 g of albumin/100 ml of prime, respectively, added to the pump prime. Pre-CPB, on CPB (15-20 min after the initiation of bypass) and warming hemoglobin, hematocrit and platelet counts were drawn on all patients. Net platelet count drop, which accounted for hemodilutional effects, was calculated for all specimens and compared to previous results obtained from the test oxygenators without albumin in the prime. The net platelet count drops for the study groups were as follows: • Sarns oxygenator with no albumin in the prime = 11.8 ± 12.5%; • Sarns oxygenator with 0.0375 g of albumin/100 ml prime = -3.7 ± 10.8%; • Sarns oxygenator with 0.125 g of albumin/100 ml prime = -2.0 ± 12.6%; • Medtronic oxygenator with no albumin in the prime = 20.1 ± 14.5%; • Medtronic oxygenator with 0.0375 g albumin/100 ml prime = -6.9 ± 8.7%; and • Medtronic oxygenator with 0.125 g albumin/100 ml prime = -14.0 ± 12.4%. Our results illustrate that adding as little as 0.0375 g albumin/100 ml prime (3 ml of 25% solution/2000 ml of prime) to the pump prime illicits the beneficial effects of surface coating on platelet loss during CPB.

Effect of Trillium™ Biopassive Surface coating of the oxygenator on platelet count drop during cardiopulmonary bypass

The new Trillium™ Biopassive Surface is a coating designed to minimize the adsorption of protein and the attachment of cells. In previous studies, we were able to demonstrate that, by coating the bypass circuit with small amounts of albumin, the drop in circulating platelet count seen with the newer low-prime hollow-fiber membrane oxygenators is eliminated. A study was undertaken to compare the Avecor Affinity™ oxygenator with albumin in the prime with the Trillium-coated Affinity. Fifty-six patients undergoing nonemergency open-heart surgery were randomly divided into two groups. One group (Albumin) received the Affinity oxygenator with 10 ml of 25% albumin added to the pump prime. The other group (Trillium) received the Trillium-coated Affinity oxygenator. To normalize the data for the effects of hemodilution, the mean net platelet count drop on bypass was calculated for each group. The Albumin group had a net platelet count drop of 0.81 ± 9.78%, while the Trillium group had a drop of 1.58 ± 13.0%. There was no significant statistical difference between the two groups. From our investigation, we concluded that Trillium Biopassive Surface coating affords the Affinity oxygenator the same protective effects on circulating platelet counts as adding albumin to the prime.

Effect of Carmeda BioActive Surface coating versus Trillium Biopassive Surface coating of the oxygenator on circulating platelet count drop during cardiopulmonary bypass.

An investigation was conducted to evaluate the effect that surface coating of the hollow-fiber membrane oxygenator had on circulating platelet count drop during cardiopulmonary bypass (CPB). Sixty patients undergoing non-emergency myocardial revascularization for coronary artery disease were randomly divided into two groups. Group one (n = 32) received the Carmeda®-coated Maxima-Plus PRF oxygenator while the patients in Group two (n = 28) received the Trillium™-coated Affinity oxygenator during CPB. The net platelet count drops for the pump specimen (15-20 min after the initiation of bypass) for the Carmeda and the Trillium groups were 3.6±15.8% and 6.2±10.2%, respectively. The net platelet count drop for the warming specimen for the Carmeda and the Trillium groups were 2.9±19.4% and 0.5±11.0%, respectively. There were no statistically significant differences between the groups. The authors conclude that using either the Carmeda®-coated Maxima-Plus PRF oxygenator or the Trillium™-coated Affinity® oxygenator afford similar benefits in regards to preserving circulating platelet counts during bypass.

Conventional approach to glucose management for diabetic patients undergoing coronary artery bypass surgery.

Continuous insulin infusion was not an effective mode of treatment in maintaining safe blood glucose levels (<200 mg/dl) during the intraoperative period of diabetic patients requiring open-heart surgery. The two modifications investigated to gain better control of the blood glucose were a change in the base solution of the cardioplegia and the use of a sliding insulin scale. Fifty patients including Type I and Type II diabetics were selected for the purpose of this study. The patients were then randomly divided into two groups categorized by the type of cardioplegic solution administered and the mode of insulin treatment. Group I patients received a dextrose 5%-based cardioplegic solution and blood glucose was treated via continuous intravenous insulin infusion. Group II patients received normal saline 0.9%-based cardioplegic solution and blood glucose was treated via sliding scale. Blood glucose levels were monitored pre- and postcardio- pulmonary bypass (CPB) and every 30 min while on CPB. Glucose values were analyzed by group t test. A p value of < 0.05 was considered statistically significant. When comparing Group I (mean=258 mg/dl) with Group II (mean= 158 mg/dl), there was a statistically significant difference between the glucose values at each of the time intervals when the glucose values were recorded. In conclusion, Group II maintained an acceptable blood glucose level (<200 mg/dl) throughout the entire intra- operative period, which suggests that the combination of the sliding insulin scale and modification of the base cardioplegic solution was an effective mode of treatment.