The effect of oxygenator choice on hypotension during cardiopulmonary bypass

Cardiopulmonary bypass (CPB) exposes blood to artificial surfaces, which induces a systemic inflammatory activation.This may contribute to hypotension during CPB. A perceived difference between two membrane oxygenators was noted. Data were collected on 222 consecutive patients; four were excluded from the analysis due to having emergency operations. One hundred and twelve (51%) patients received the Apex oxygenator whilst 106 (49%) received the Quadrox. There was no difference between the two groups in the primary outcome; 90/112 patients (80%) in the Apex group and 77/106 (73%) in the Quadrox group (p=0.18, OR: 0.65; 95% CI: 0.34, 1.22) received meteraminol due to marked hypotension during CPB. There was also no difference in the secondary outcomes, length of stay in ICU (22.8 versus 22.7 hours, (OR 0.79, 95% CI: 0.42, 1.48, p=0.16) and length of stay in hospital (8.5 days versus 8.0 days (OR: 0.83, 95% CI: 0.48, 1.45; p=0.52). The choice of oxygenator between the Apex and Quadrox does not have an effect on hypotension in cardiac surgery.     

氨茶碱对心肌的保护作用

目的探讨氨茶碱在体外循环(CPB)心脏瓣膜置换术中的心肌保护作用及其可能机制。方法将择期行心脏瓣膜置换术的30例风湿性心脏瓣膜病患者随机分为氨茶碱组和对照组,每组各15例。氨茶碱组麻醉诱导后静脉滴注氨茶碱(5 mg/kg)。分别测定CPB转流前及术后不同时期血浆肌钙蛋白Ⅰ(cTnI)、心肌环磷酸腺苷(cAMP)和髓过氧化物酶(MPO)以及主动脉血/冠状静脉窦血中性粒细胞(PMN)比值等;同时观察血流动力学等临床指标。结果两组患者各临床指标差异均无统计学意义;升主动脉开放后两组cTnI均比CPB前升高,但氨茶碱组显著低于对照组;升主动脉开放后30 min,两组cAMP均降低,但氨茶碱组心肌cAMP含量显著高于对照组,MPO活性及主动脉血,冠状静脉窦血PMN比值显著低于对照组。结论在CPB心脏瓣膜置换术中,氨茶碱具有一定的心肌保护作用;其机制可能与升高心肌cAMP、抑制白细胞对心肌组织的浸润有关。     

Monitoring of CO2 exchange during cardiopulmonary bypass: the effect of oxygenator design on the applicability of capnometry

The correlation between pCO2 values in blood and in exhaust gas from the oxygenators was examined during cardiopulmonary bypass (CPB) using one bubble oxygenator and three membrane oxygenators. Forty-seven CPBs were performed, 17 with Compactflow (Dideco, Italy), 10 with Maxima (Medtronic Inc., USA), 10 with Cobe CML (Cobe Laboratories, USA) membrane oxygenators and 10 with Hi-Flex (Dideco, Italy) bubble oxygenators. Blood samples were taken both from arterial and venous lines of the oxygenator. A capnometer was connected to the oxygenator gas exhaust port and CO2 fraction was measured at the time of drawing blood samples. CO2 pressure in the gas phase was calculated from the product of the CO2 fraction and water vapour-corrected barometric pressure. Blood gases were measured at 37 degrees C and the pCO2 value was corrected to the temperature of the arterial line. The correlation between blood and exhaust gas pCO2 was good in all the oxygenators examined, ranging from 0.921 to 0.976. The standard error of estimate (SEE) was in the range of about +/- 2 mmHg for all the oxygenators. The systematic error (slope and intercept of the correlation line) varied depending on the construction of the oxygenator, with countercurrent design having the best overall correspondence. Based on the results of this study it can be concluded that arterial or venous CO2 pressure can be monitored with a capnometry device coupled to the oxygenator gas outlet port.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

常温体外循环心脏不停跳手术对TNF-α影响的临床研究

目的 探讨常温体外循环（CPB）心脏不停跳手术对血清肿瘤坏死因子a（TNF-α）含量的影响及意义。方法 30例先天性房间隔缺损患者，随机分为观察组（n=15例）在常温心脏不停跳下手术；对照组（n=15例）在低温心脏停跳下手术。全组均在CPB前、结束即刻、结束后2h、结束后24h取静脉血样标本，运用酶联免疫吸附试验（ELISA）方法检测血清中TNF-α的含量。两组之间各检测点进行比较，并进行t检验，分析数值。结果 CPB结束后两组TNF-α含量均升高，观察组TNF-α在CPB结束后各时点的升高幅度低于对照组（P〈0．05）。结论 常温心脏不停跳手术可以减少TNF-α的释放，从而减轻CPB术后炎性反应。     

Comparison of a Duraflo II-coated cardiopulmonary bypass circuit and a trillium-coated oxygenator during open-heart surgery

BACKGROUND: Cardiopulmonary bypass (CPB) evokes a systemic inflammatory response. In attempting to improve the biocompatibility of the equipment, various methods to coat the inner surfaces of the CPB systems have been developed. The present study compares a Trillium Biopassive surface-coated Affinity oxygenator with a Duraflo II totally heparin-coated CPB system. METHODS: Low-risk patients admitted for primary coronary artery bypass grafting or aortic valve replacement were randomized to operation using the Trillium- or the Duraflo II-coated setups. Heparin concentration, complement activation (C3bc activation products and terminal complement complex (TCC)), platelet activation (platelet numbers and beta-thromboglobulin (BTG)), leukocyte activation (leukocyte numbers and myeloperoxidase (MPO)), coagulation (thrombin/antithrombin complexes (TAT)) and fibrinolytic activity (plasmin/alpha2-antiplasmin complexes (PAP)) were measured during CPB and two hours postoperatively. RESULTS: Platelet counts decreased during CPB, without significant intergroup differences. The median BTG concentration increased moderately in both groups and were slightly higher in the Trillium group during CPB (p < 0.05), but not postoperatively. Complement activation products (C3bc and TCC), leukocyte counts, MPO, TAT and PAP activity showed no differences between the two groups. CONCLUSIONS: There were small differences in the inflammatory response between the two extracorporeal circulation devices compared in this study.     

A clinical evaluation of platelet function, haemolysis and oxygen transfer during cardiopulmonary bypass comparing the Quantum HF-6700 to the HF-5700 hollow fibre membrane oxygenator

The continued improvement of oxygenators is an important aspect of patient safety during cardiopulmonary bypass (CPB). The purpose of this study was to compare the Bard William Harvey HF-5700 oxygenator to the upgraded Bard Quantum HF-6700, which has recently been introduced into clinical practice. No clinical evaluation of this device has been published to date. The two oxygenators differ principally in that the Quantum has a smaller priming volume, achieved at the expense of a smaller membrane surface area which could result in sub-optimal gas exchange characteristics, increased haemolysis and increased platelet dysfunction during CPB. Twenty adult patients undergoing elective, first time coronary artery bypass grafting (CABG) were randomly assigned either to the HF-5700 (n=10) or to the HF-6700 (n=10) group. One patient underwent mitral valve repair in addition to CABG and was excluded from further study. There were no statistically significant differences in either preoperative or operative parameters between the two groups. Samples were obtained at the start of CPB, at 30 min, 60 min, at the end of CPB and at 1 h following termination of CPB. No significant differences between the two groups were found in oxygen transfer, haemolysis (plasma haptoglobin levels) or platelet function (a novel platelet activating factor (PAF)-induced platelet activation test) at any of the time points during CPB. It was concluded that the Quantum HF-6700 matches the HF-5700 for the parameters studied, whilst having the advantage of requiring a smaller priming volume.     

先天性心脏病患儿血管内皮生长因子单核苷酸多态性研究

目的 研究中国汉族人群中血管内皮生长因子VEGF 936C>T多态性与发生先天性心脏病危险的关系.方法 以PCR-RFLP技术分析105例先天性心脏病和167例非先天性心脏病患者VEGF基因 936C>T(rs3025039)多态性,比较不同基因型与先天性心脏病发生危险的关系;用ELISA法测定两组对象血浆VEGF浓度.结果 VEGF基因 936C>T 3种基因型在先天性心脏病组和非先天性心脏病对照组的分布差异不具有显著性,先天性心脏病组血浆VEGF的浓度明显高于对照组.结论 VEGF基因 936C>T多态性可能不是中国汉族人群先天性心脏病发生的危险因素,但VEGF增高可能与先天性心脏病某些并发症相关.     

体外循环中盐酸戊乙奎醚对肺损伤的保护作用

目的:研究盐酸戊乙奎醚时体外循环(CPB)炎症因子的影响及对肺损伤的保护作用.方法:24例择期首次行心脏瓣膜置换术患者,随机分为盐酸戊乙奎醚组(A组)和对照组(C组),每组12例.分别于诱导切皮前(T1)、转流30 min(T2)、停CPB 1 h(T3)、4 h(T4)、24 h(T5)抽取动脉血,测定红细胞压积和动脉血气分析,计算呼吸指数RI,测定血浆TNF-α、IL-6浓度.结果:两组间血浆IL-6、TNF-α水平和RI值在CPB前T1时差异无统计学意义(t≤1.82,P＞0.05).两组T2-5各时点TNF-α、IL-6均高于T1(F≥6.21,P＜0.05),A组T2-5各时点TNF-α、IL-6浓度明显低于C组同时点值(t≥2.41,P＜0.05),两组T3-T4时点RI均高于T1时点(F≥5.87,P＜0.05),A组中T3,T4时点RI较C组同时点明显降低(t≥2.38,P＜0.05).结论:盐酸戊乙奎醚能有效地抑制CPB心脏直视手术围术期炎症因子的释放,改善肺功能.     

体外循环手术中血小板单采对血液的保护作用

目的　探讨在体外循环心脏手术中血小板单采对血液的保护作用 ;方法　选择 2 0例行心脏瓣膜手术患者 ,随机分为实验组和对照组 ,实验组采用血小板单采技术 +常规体外循环 ,对照组只采用常规体外循环 ,其他血液保护措施两组相同 ;结果　①实验组血小板采集量均在患者血小板总数的 2 0 %以上 ;②实验组术中血液制品 (全血和血浆 )用量较对照组明显减少 ,差异有显著性 ;③两组间Hb及Hct各时点变化趋势一致 ;④围手术期患者血小板计数的动态变化两组差异不大 ,而实验组恢复较快 ;⑤实验组术后血小板聚集功能明显优于对照组 ,差异有显著性 ;⑥实验组术后凝血酶原恢复时间明显较对照组快 ,差异有显著性 ;⑦实验组术后各分时段引流量较对照组明显减少 ,差异有显著性。结论　体外循环术中血小板单采能够保护血小板免遭体外循环的破坏 ,明显减少术后出血 ,起到良好的血液保护作用。     

体外循环手术中C3、C4的检测意义

目的 了解体外循环(CPB)手术对病人血浆中C3、C4的影响。方法 用透射比浊法测定行心脏瓣膜置换术前后病人血浆中C3、C4浓度,并进行比较。结果 术前与术后血浆中C3、C4差异有显著性(P<0.05),血浆中C3、C4降低的谷值在CPB末。结论 CPB导致术后早期大量补体激活,易引起全身性炎症反应综合征(SIRS),减少补体激活程度可降低炎症反应强度。     

Cefamandole kinetics during cardiopulmonary bypass

The kinetics of cefamandole during cardiac surgery was studied in 16 adult patients given a single intravenous infusion of 20 mg/kg at the time of anesthesia induction. Five normal volunteers who received the same dose served as controls. Cardiopulmonary bypass (CPB) was found to signficantly increase the half-life (t 1/2) of cefamandole. The mean t 1/2 during CPB (113.2 min) was longer than the terminal t 1/2 in normal volunteers (52.0 min; p less than 0.005). Throughout CPB (maximum, 3,7 hr), cefamandole plasma levels were maintained above the minimum inhibitory concentration for those organisms most likely to cause postoperative infections. We conclude that if 20 mg/kg of cefamandole is given within an hour of the beginning of cardiovascular surgery, a supplemental dose is not needed until the patient has been on CPB for at least four hours.     

The effect of zero-balanced ultrafiltration during cardiopulmonary bypass on S100b release and cognitive function

Zero-balanced ultrafiltration (ZBUF) might reduce the systemic inflammatory response (SIRS) during cardiopulmonary bypass (CPB) by removing inflammatory mediators. The objective of this study was to determine the effect of ZBUF on postoperative serum S100b levels, a marker of neuronal injury. In addition, the possible effects of ZBUF on postoperative neurocognitive function were assessed. Sixty patients undergoing elective coronary bypass grafting were randomly assigned either to a control group or to a protocol group in which ZBUF was performed. Serum S100b levels were measured five minutes after intubation, at the end of bypass and eight and 20 hours after arrival at the intensive care unit (ICU). Cognitive function was assessed with neuropsychological tests on the day before the operation and the sixth day after surgery. The S100b level at 20 hours after arrival at the ICU was 0.27 g/L (SD 0.16) in the control and 0.25 g/L (SD 0.12) in the group with ZBUF. There were no statistical differences at any time between the two groups. S100b was not detectable in the ultrafiltrate, indicating that these results were not obscured by washout of S100b. Thirteen patients (52%) in the control group and 14 patients (56%) in the ZBUF group showed a cognitive deficit. In conclusion, ZBUF during CPB does not decrease the release of S100b. This result is not affected by washout. ZBUF did not reduce the incidence of early neurocognitive deficits. The role of SIRS in the development of cognitive dysfunction following CPB remains to be resolved.     

The importance of pulmonary artery circulation during cardiopulmonary bypass

This study sought to determine changes in transpulmonary difference in blood cells and alveolar-arterial oxygen (A-aO2) gradient when pulmonary artery circulation was obstructed in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Eighteen patients were divided into group A (control group; X-clamp placed on aorta, n = 9) and group B (pulmonary ischaemia group; X-clamp placed on aorta and pulmonary artery, n = 9). Haematological parameters were compared before CPB and up to 90 min after declamping. A-aO2 gradient differences were compared before and 2 h and 6 h after declamping. A transpulmonary increase in leucocyte levels normalized after 60 min in group A but remained higher in group B. A transpulmonary increase in neutrophils normalized after 60 min in group A and 90 min in group B. Increased lymphocyte levels normalized after 30 min in group A and 90 min in group B. A-aO2 gradient was determined as: group A (294.8 +/- 74.3) and group B (321.2 +/- 73.3) before X-clamping; group A (132.7 +/- 22.7) and group B (236.6 +/- 41.5) 2 h after declamping; and group A (72.2 +/- 22.7) and group B (189.4 +/- 88.9) 6 h after declamping. When pulmonary artery circulation was obstructed during the X-clamping period, leucocyte, neutrophil and lymphocyte sequestration within both lungs increased, and an increased A-aO2 gradient was observed because of tissue damage. To prevent post-operative complications, precautions to maintain normal pulmonary artery circulation are recommended.     

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.     

体外循环术中高血糖对术后认知功能的影响

目的研究体外循环（CPB）心脏手术中高血糖症与术后认知功能障碍的关系。方法本院86例CPB下行心脏瓣膜置换术（CVR）或冠状动脉旁路移植术（CABG）的非糖尿病成年患者,在术前及术后6周用标准化神经系统检查进行认知功能评分,并在术中监测患者血糖水平,按照术中出现高血糖（〉200mg／dL）与否分为A、B两组,比较两组患者的术前术后认知功能评分,分析术中高血糖与术后认知功能障碍的关系。结果术中出现高血糖的患者,与术中未出现高血糖的患者比较,术后认知功能评分显著降低,认知功能障碍发生率明显增加（P〈0．01）。结论在接受体外循环手术的患者中,术中高血糖是术后出现认知功能障碍的独立毹险因素。