Prospective randomized trial of normothermic versus hypothermic cardiopulmonary bypass on cognitive function after coronary artery bypass graft surgery.

BACKGROUND: Despite significant advances in cardiopulmonary bypass (CPB) technology, surgical techniques, and anesthetic management, central nervous system complications occur in a large percentage of patients undergoing surgery requiring CPB. Many centers are switching to normothermic CPB because of shorter CPB and operating room times and improved myocardial protection. The authors hypothesized that, compared with normothermia, hypothermic CPB would result in superior neurologic and neurocognitive function after coronary artery bypass graft surgery. METHODS: Three hundred patients undergoing elective coronary artery bypass graft surgery were prospectively enrolled and randomly assigned to either normothermic (35.5-36.5 degrees C) or hypothermic (28-30 degrees C) CPB. A battery of neurocognitive tests was performed preoperatively and at 6 weeks after surgery. Four distinct cognitive domains were identified and standardized using factor analysis and were then compared on a continuous scale. RESULTS: Two hundred twenty-seven patients participated in 6-week follow-up testing. There were no differences in neurologic or neurocognitive outcomes between normothermic and hypothermic groups in multivariable models, adjusting for covariable effects of baseline cognitive function, age, and years of education, as well as interaction of these with temperature treatment. CONCLUSIONS: Hypothermic CPB does not provide additional central nervous system protection in adult cardiac surgical patients who were maintained at either 30 or 35 degrees C during CPB.     

Prospective Randomized Trial of Normothermic versus Hypothermic Cardiopulmonary Bypass on Cognitive Function after Coronary Artery Bypass Graft Surgery

Background : Despite significant advances in cardiopulmonary bypass (CPB) technology, surgical techniques, and anesthetic management, central nervous system complications occur in a large percentage of patients undergoing surgery requiring CPB. Many centers are switching to normothermic CPB because of shorter CPB and operating room times and improved myocardial protection. The authors hypothesized that, compared with normothermia, hypothermic CPB would result in superior neurologic and neurocognitive function after coronary artery bypass graft surgery.

Methods : Three hundred patients undergoing elective coronary artery bypass graft surgery were prospectively enrolled and randomly assigned to either normothermic (35.5-36.5[degrees]C) or hypothermic (28-30[degrees]C) CPB. A battery of neurocognitive tests was performed preoperatively and at 6 weeks after surgery. Four distinct cognitive domains were identified and standardized using factor analysis and were then compared on a continuous scale.

Results : Two hundred twenty-seven patients participated in 6-week follow-up testing. There were no differences in neurologic or neurocognitive outcomes between normothermic and hypothermic groups in multivariable models, adjusting for covariable effects of baseline cognitive function, age, and years of education, as well as interaction of these with temperature treatment.     

Cardiopulmonary bypass in surgery for interrupted aortic arch

Interrupted aortic arch is a complicated congenital heart defect. Because of its anatomic features, the conventional cardiopulmonary bypass (CPB) procedure is not suitable for the surgery of this type of lesion. Thus, we conducted a retrospective study of CPB in surgery for the disease. Ten patients with interrupted aortic arch underwent surgery by one of three different CPB methods, including profound hypothermia with circulatory arrest in four cases, profound hypothermia with low flow rate in five cases, and normothermia in one case. In profound hypothermic CPB, both ascending aorta and main pulmonary artery were cannulated. Through these two cannulas, the flow was pumped to the upper and lower body separately to cool down the body temperature. After cooling, the main pulmonary artery cannula was removed and interrupted aortic arch was corrected either under low flow rate perfusion or under circulatory arrest. After this, the other intracardiac lesions were repaired under conventional CPB. At the end of CPB, one patient demonstrated third-degree atria-ventricular block and required reinstituting CPB and a second procedure to repair the ventricular septal defect (VSD). In the intensive care unit, one patient developed lung infection and dyspnea after extubation that required intubation and mechanical ventilation for another several days. Another patient required 3 days of peritoneal dialysis caused by low cardiac output, hyperkalemia, and oliguria. All patients survived. The mechanical ventilation times were from 8 hours to 8 days and stays in the intensive care unit were from 4 to 12 days. Profound hypothermic cardiopulmonary bypass either with low flow rate or with circulatory arrest is equally the preferable choice for the surgery of interrupted aortic arch.     

Successful management after cardiopulmonary bypass without administration of protamine in a patient with severe food allergy--beneficial result with the use of heparin-coated bypass circuit

We experienced the anesthetic management for cardiac surgery without the administration of protamine in a patient with severe food allergy. The patient, a 15-year-old boy, who had been avoiding many kinds of food including fish due to severe food allergy, received a correction of ventricular septal defect under cardiopulmonary bypass (CPB). To detect intraoperative drugs, including protamine, which might induce allergic reaction, we performed intradermal tests and prick tests. We used heparin-coated bypass circuit to minimize the amount of heparin necessary for anticoagulation during CPB. After CPB, hemostasis was achieved without the administration of protamine, and the patient received neither transfusion nor blood product throughout the perioperative period. Avoidance of protamine is advisable if the patient is allergic to food especially fish. The use of heparin-coated bypass circuit should be considered to establish hemostasis without protamine after CPB and to reduce blood products.     

Single-stage unifocalization and correction with median sternotomy in complex pulmonary atresia

OBJECTIVE: This study assessed the surgical and post-operative outcome of single-stage complete unifocalization and repair procedure in patients with complex pulmonary atresia. METHODS: From 1999 to 2001, we performed complete unifocalization and correction in 10 patients with complex pulmonary atresia. Their ages ranged from 10 months to 17 years. All patients were evaluated with pulmonary angiography and divided into two groups according to the development of native pulmonary arteries. Group I patients had hypoplastic pulmonary arteries and MAPCAs and Group II patients had only MAPCAs without native pulmonary arteries. With median sternotomy, all MAPCAs were prepared and anastomozed to native pulmonary arteries in group I patients or on a pericardial roll in group II patients without using cardiopulmonary bypass. Right ventricle to pulmonary arterial continuity was established with a valved conduit under CPB. VSD was closed in two patients. RESULTS: Eight patients had complete repair without VSD closure. They were followed periodically with pulmonary angiography. Two patients developed congestive heart failure. One of them was reoperated and VSD was closed. The other patient died because of untractable congestive heart failure. The decision for VSD closure was made in two patients due to suitable pulmonary arterial vascular tree. However, one of them had to be reoperated and VSD patch was removed. This patient died because of sepsis on the postoperative 26th day. We are following the rest of the patients with echocardiography and pulmonary angiography. CONCLUSION: Single stage complete unifocalization and repair should be the treatment of choice in patients with complex pulmonary atresia. This procedure provides a significant development in neopulmonary arterial system. However, the accurate criterias for VSD closure are still controversial. After the operation, these patients had to be followed closely with echocardiography and pulmonary angiography because of the absolute risk of congestive heart failure in patients with VSD left open.     

Differential brain and body temperature during cardiopulmonary bypass--a randomised clinical study.

OBJECTIVE: Maintenance of normothermia during cardiopulmonary bypass (CPB) may have advantages over hypothermia but there is a potential increased hazard of neurological injury. A novel aortic cannula (Cobra catheter, Cardeon Corp., Cupertino, CA, USA) which compartmentalises the aorta may allow simultaneous brain cooling during maintained corporeal normothermia. We investigated the thermal efficacy of this technique. METHODS: We randomized 60 adult patients to normothermic CPB (n=30, temp=35 degrees C) or to differential temperature management (Cobra cannula). Nasopharyngeal (NPT) and jugular bulb (JB) temperatures were used as surrogates for brain temperature while bladder temperature (BLT) represented the body (corporeal) temperature. Brain (radial) and corporeal (femoral) mean arterial pressure (MAP) together with jugular bulb and mixed venous saturations were monitored to assess perfusion adequacy. Transcranial Doppler was used to assess high intensity transient signals (HITS). All patients had neuropsychometric assessment pre-operatively and at 1 and 8 weeks post-operatively. RESULTS: Demographic and CPB variables were comparable. A 3.2+/-0.46 degrees C differential between BLT and NPT was reached in all Cobra patients after 5.5+/-3.6 min (P<0.001). A 5 degrees C differential was reached in 29 patients after 12+/-7.5 min. The mean difference was 6.6+/-1 degrees C. MAP was maintained above 50 mmHg and venous saturations above 60% in both groups throughout. Blood requirements, extubation time and ITU stay were no different. Embolic counts and neuropsychometric outcomes were not different between groups. CONCLUSIONS: Differential temperature management using the Cobra aortic catheter is possible. Further studies are necessary to establish whether the hypothesized advantages of combining corporeal normothermia with brain hypothermia can be realised.     

Anesthesia for percutaneous transcatheter closure of perimembranous ventricular septal defect

OBJECTIVE: To review the anesthetic management for percutaneous transcatheter closure of perimembranous ventricular septal defect (VSD) with an Amplatzer asymmetric occluder device and to highlight the hemodynamic effects and potential complications associated with its delivery. DESIGN: Retrospective review of prospectively collected data. SETTING: University-affiliated teaching hospital. PARTICIPANTS: Nine consecutive children undergoing elective percutaneous transcatheter closure of perimembranous VSD. INTERVENTIONS: General anesthesia with sevoflurane for cardiac catheterization and percutaneous transcatheter device placement. MEASUREMENTS AND MAIN RESULTS: Ten anesthetics were delivered in 9 children ages 23 to 65 months with perimembranous VSD for attempted placement of an Amplatzer asymmetric device. The device was successfully placed in 7 patients. In 1 patient the device embolized to the right femoral artery, and was retrieved with a bioptome. Fluoroscopy time (59.8 +/- 17.24 min) was prolonged compared to that in other studies of placement of this device. All patients had episodes of arrhythmia and hemodynamic disturbance. Arrhythmias ranged from atrial or ventricular ectopic events to various degrees of atrioventricular block. Complete heart block occurred during the procedure in 1 patient and after the procedure in another patient. Hypotensive episodes occurred in 7 patients, and were attributed to arrhythmias in 5 patients and hypovolemia in 2 patients. Two patients were given blood transfusions after the procedure because they had signs of hypovolemia and a greater than 10% decrease in hemoglobin levels. CONCLUSIONS: Anesthesia for perimembranous VSD occluder placement is associated with hemodynamic instability, arrhythmias, prolonged procedure times, and inevitable and sometimes substantial blood loss.     

Importance of anesthetic management for the patients with systolic anterior motion after mitral valve plasty

Systolic anterior motion (SAM) after mitral valve plasty (MVP) occurs at an incidence of 1 to 4%. The management is related to this condition. Three patients developed SAM just after MVP. In the first patient, a 51-year-old man, volume loading and methoxamine were employed, which elevated arterial pressure, but led to a severer catastrophe. This suggested the indication of mitral valve replacement to the surgeons. The second patient, a 75-year-old woman, underwent re-annuloplasty after the first MVP because of incomplete correction. Before the separation from the second CPB, continuous dopamine infusion was started because we feared that the long CPB time would have impaired LV function. The TEE showed the catastrophe, but it disappeared just after the discontinuation of the dopamine infusion and the administration of propranolol and norepinephrine. The last patient was a 72-year-old woman. For the catastrophe, propranolol was given and an immediate improvement followed with TEE showing no evidence of the catastrophe. The goal for anesthetic management of the catastrophe after MVP is to decrease the hyperdynamic ventricular contraction. We managed SAM by volume loading and discontinuation of beta-stimulants and/or administration of beta-blockers.     

姑息性大动脉调转手术的麻醉管理

目的 总结姑息性大动脉调转手术(palliative arterial switch operation,PASO)的麻醉管理. 方法 回顾性总结分析28例于我院行PASO的完全性大动脉转位合并室间隔缺损(transposition of the great arteries with ventricular septal defect,TGA/VSD)或Taussing-Bing综合征患者的临床资料.28例患者年龄中位数为4岁(1月～25岁),体重中位数为12.5 kg(3.6～43kg),术前均诊断为重度肺动脉高压,术前SpO2波动在44％～91％. 结果 所有患者麻醉过程平稳,平均CPB时间为(223±81) min,平均主动脉阻断时间为(153±32) min.平均室间隔补片留孔大小为(5.3±1.5) mm.术后机械辅助通气时间中位数为36 h(7～408 h),ICU停留时间中位数为5.5 d(2～27 d).术后平均SpO2为(96±2)％,与术前比较,差异有统计学意义(P＜0.05).住院死亡5例(18％),余好转出院.出院患者中5例在出院后的1～5年间行介入残余室缺分流堵闭术. 结论 充分的术前准备和评估,平顺的麻醉诱导和维持,围手术期肺动脉高压的处理,早期合理地应用血管活性药物以及出凝血功能的调整,有利于PASO的成功.     

5kg以下低体重婴儿室间隔缺损的外科治疗

目的报道低体重婴儿室间隔缺损(VSD)伴肺动脉高压的外科手术修补结果和体会.方法1994年3月至1999年12月,对50例2～11月龄,体重3.2～5.0?kg的VSD病婴采用中度低温体外循环行补片修补术.全组术前均伴中度以上肺动脉高压(Pp/Ps平均为0.68±0.09).结果住院死亡2例,住院死亡率为4%,死亡原因分别为心包压塞和脑昏迷.术后主要并发症为肺部感染、肺动脉高压危象和心律失常.结论对5?kg以下低体重婴儿的较大VSD采用外科手术修补可以取得满意效果.     

体外循环对室间隔缺损婴儿手术后肺功能的影响

目的评估体外循环(CPB)对是否合并肺动脉高压先天性室间隔缺损(V SD)婴儿手术后肺功能的影响。方法行V SD修补术婴儿20例,根据是否合并肺动脉高压分为肺动脉高压组和无肺动脉高压组,每组各10例。分别于CPB前、CPB后3 h、6 h、9 h、12 h、15 h、18 h、21 h和24h测定肺功能,并记录手术后机械通气时间和重症监护时间。结果CPB前无肺动脉高压组婴儿肺功能各项指标显著优于肺动脉高压组(P<0.01),但CPB后各时间段除呼吸指数(R I)外其它指标均较术前显著降低(P<0.05),尤以CPB后9 h、12 h和15h较明显(P<0.01)。肺动脉高压组CPB后3h肺功能指标较CPB前改善,但在CPB后9h、12h和15h仍明显较CPB前差(P<0.05);CPB后21h、24h两组婴儿肺功能指标开始接近CPB前。结论CPB对V SD婴儿术后肺功能均有不同程度的损害,但对合并肺动脉高压的婴儿,手术带来的益处超过了CPB对肺的损害;积极改善术后心功能,可避免术后肺功能低谷的出现;若术后心功能稳定、无反应性肺动脉高压和肺动脉高压危象的发生,术前合并肺动脉高压的婴儿同样也能早期撤离呼吸机。     

Modified ultrafiltration lowers adhesion molecule and cytokine levels after cardiopulmonary bypass without clinical relevance in adults.

OBJECTIVE: Cardiac surgery with cardiopulmonary bypass (CPB) results in expression of cytokines and adhesion molecules (AM) with subsequent inflammatory response. The purpose of the study was to evaluate the clinical impact of modified ultrafiltration (MUF) and its efficacy in reducing cytokines and AM following coronary artery bypass grafting (CABG) in adults. METHODS: A prospective randomized study of 97 patients undergoing elective CABG was designed. Fifty patients were operated on using normothermic and 47 patients using hypothermic CPB. The normothermic group was subdivided into a group with modified ultrafiltration (n = 30) and a group without MUF (n = 20). In the hypothermic group 30 patients received MUF compared to 17 patients serving as controls. MUF was instituted after CPB for 15 min through the arterial and venous bypass circuit lines. Cytokines (IL-6, IL-8, TNF-alpha, IL-2R) and adhesion molecules (sE-selectin, sICAM-1) were measured preoperatively, pre-MUF, in the ultrafiltrate, 24 h, 48 h and 6 days after surgery by chemiluminescent enzyme immunometric assay or enzyme-linked immunosorbent assay (ELISA). Clinical parameters were collected prospectively until discharge. RESULTS: In all patients AM and cytokines were significantly elevated after normothermic and hypothemic CPB. AM and cytokines were significantly higher in hypothermia compared to normothermia. In hypothermic CPB sE-selectin was decreased after 24 h by 37% (P < 0.0063) and by 40% (P < 0.0027) after 48 h postoperatively. ICAM-1 was reduced by 43% (P < 0.0001) after 24 h and by 60% (P < 0.0001) after 6 days. Similar results were seen in cytokines with reduction up to 60% after 24 h. Changes after 48 h were noticeable but not significant. Reduction of AM and cytokines after normothermic CPB was minimal. Neither in normothermia, nor in hypothermia has sIL-2R been effectively removed from the circulation. There were no significant differences in the clinical variables between the patients with or without MUF. CONCLUSION: AM and cytokines are significantly elevated after hypothermic CPB compared to normothermic CPB. MUF led to a significant reduction in cytokine and AM levels after hypothermic CPB, except for IL-2R. MUF showed minimal effect in normothermia. We conclude that MUF is an efficient way to remove cytokines and AM. However, we were unable to demonstrate any significant impact of MUF in outcome of adults after elective CABG.     

Active cooling during open repair of thoraco-abdominal aortic aneurysms improves outcome.

OBJECTIVE: Evaluate impact of active cooling with partial cardiopulmonary bypass (CPB) and low systemic heparinization during open repair of thoracoabdoninal aortic aneurysms. METHODS: Prospective analysis of 100 consecutive patients undergoing surgical repair of thoracoabdominal aortic aneurysms. Partial CPB and normothermic (36 degrees C) or hypothermic (29 degrees C) perfusion was selected in accordance to the surgeons preference. In the hypothermic group, aortic cross clamp was applied when the target temperature of the venous blood was achieved and rewarming was started after declamping. RESULTS: 52/100 patients (62.2+/-10.9 years) received normothermic and 48/100 patients hypothermic perfusion (63.8+/-10.6 years: NS). Emergent procedures accounted for 18/52 (35%) with normothermia vs. 21/48 (44%: NS) with hypothermia. The number of aortic segments (eight = maximum including arch and bifurcation) replaced was 3.9+/-1.5 with normothermia vs. 4.1+/-1.5 with hypothermia (NS); Crawford type II aneurysms accounted for 21/52 patients (40%) for normothermia vs. 20/48 (42%:NS) for hypothermia. Total clamp time was 38+/-21 min with normothermia vs. 47+/-28 min with hypothermia (P=0.05). Pump time was 55+/-28 min with normothermia vs. 84+/-34 min with hypothermia (P=0.001). Mortality at 30 days was 8/52 patients (15%) with normothermia vs. 2/48 (4%) with hypothermia (P=0.06; odds ratio = 4.1). Parapareses/plegias occurred in 4/52 patients (8%) with normothermia vs. 4/48 (8%) with hypothermia (NS). Revisions for bleeding were required in 4/52 patients (8%) with normothermia vs. 2/48 patients (4%) with hypothermia (P=0.38). Revisions for distal vascular problems were necessary in 5/52 patients (10%) with normothermia vs. 2/48 (4%) with hypothermia (P=0.25). Freedom from death, paraplegia, and surgical revision was 89.9% with normothermia vs. 94.8% with hypothermia (P=0.04; odds ratio 2.0). CONCLUSIONS: Active cooling during repair of thoracoabdominal aortic aneurysms allows for longer cross-clamp times, more complex repairs and improves outcome.     

Hemostatic Activation and Inflammatory Response during Cardiopulmonary Bypass: Impact of Heparin Management

Background: Cardiac surgery involving cardiopulmonary bypass (CPB) leads to fulminant activation of the hemostatic-inflammatory system. The authors hypothesized that heparin concentration-based anticoagulation management compared with activated clotting time-based heparin management during CPB leads to more effective attenuation of hemostatic activation and inflammatory response. In a randomized prospective study, the authors compared the influence of anticoagulation with a heparin concentration-based system (Hepcon HMS; Medtronic, Minneapolis, MN) to that of activated clotting time-based management on the activation of the hemostatic-inflammatory system during CPB.

Methods: Two hundred elective patients (100 in each group) undergoing standard cardiac surgery in normothermia were enrolled. No antifibrinolytic agents or aprotinin and no heparin-coated CPB systems were used. Samples were collected after administration of the heparin bolus before initiation of CPB and after conclusion of CPB before protamine infusion.

Results: There were no differences in the pre-CPB values between both groups. After CPB there were significantly higher concentrations (P < 0.05) for heparin and a significant reduction in thrombin generation (25.2 +/- 21.0 SD vs. 34.6 +/- 25.1), d-dimers (1.94 +/- 1.74 SD vs. 2.58 +/- 2.1 SD), and neutrophil elastase (715.5 +/- 412 SD vs. 856.8 +/- 428 SD), and a trend toward lower [beta]-thromboglobulin, C5b-9, and soluble P-selectin in the Hepcon HMS group. There were no differences in the post-CPB values for platelet count, adenosine diphosphate-stimulated platelet aggregation, antithrombin III, soluble fibrin, Factor XIIa, or postoperative blood loss.     

Neuronal and astroglial injuries in patients undergoing coronary artery bypass grafting and aortic arch replacement during hypothermic cardiopulmonary bypass

More than 50% of patients suffer neuropsychologic impairment after cardiac surgery. We measured neuron-specific enolase (NSE) and S-100 protein (S-100) in patients' serum as putative markers of neuronal and astroglial cell injury, respectively. Group I (n = 13) underwent coronary artery bypass grafting (CABG) with mild hypothermic cardiopulmonary bypass (CPB); Group II (n = 6) underwent aortic arch replacement with deep hypothermic CPB; Group III (n = 8) underwent CABG under normothermia without CPB. During and after the operation, serum levels of NSE and S-100 were significantly increased only in Groups I and II (during CPB), NSE still being increased 12 h after surgery in Group II. This suggests that neuronal and astroglial cell injuries are more likely in patients undergoing CABG with mild hypothermic CPB or aortic arch replacement with deep hypothermic CPB than in those undergoing CABG under normothermia without CPB. However, these increases of NSE and S-100 failed to reflect clinical brain damage. Rather, an electroencephalogram, was only capable of detecting neurologic complications after surgery. Implications: Neuronal and astroglial cell injuries are likely to occur during coronary artery bypass grafting with mild hypothermic cardiopulmonary bypass (CPB) or aortic arch replacement with deep hypothermic CPB. Conversely, patients undergoing coronary artery bypass grafting without CPB under normothermic conditions may be less likely to suffer brain cell injury.     

麻醉管理中应用快速康复外科策略对患者免疫功能的影响

目的探讨应用快速康复外科(enhanced recovery after surgery,ERAS)策略进行术中麻醉管理对腹腔镜直肠癌手术患者机体免疫功能的影响。方法前瞻性研究陕西省人民医院2013年1月至2015年1月进行腹腔镜直肠癌根治手术的患者90例,男51例,女39例,年龄48~70岁,ASAⅠ~Ⅲ级。采用随机数字表法,随机分为ERAS组(A组)和常规对照组(B组),每组45例。A组应用硬膜外麻醉联合全身麻醉,加强术中保温,限制术中液体的输入,术中和术后尽量采用短效麻醉药等一系列快速康复外科策略进行麻醉管理。B组采用常规麻醉管理。记录术前1d、术后1、3d的CRP、IL-6浓度以及CD3~+、CD4~+、CD8~+和CD4~+/CD8~+。结果与术前1d比较,术后3d两组患者CRP及IL-6浓度均明显升高(P0.05),术后3d两组患者CD3~+、CD4~+、CD8~+以及CD4~+/CD8~+明显下降(P0.05);术后3dA组CRP及IL-6浓度明显低于B组(P0.05),CD3~+、CD4~+、CD8~+以及CD4~+/CD8~+明显高于B组(P0.05)。结论直肠癌手术术中麻醉管理应用快速康复外科策略可以减轻手术对患者的应激反应,起到免疫保护作用。     

Mitochondrial myopathies and anaesthesia

The mitochondrial myopathies consist of a heterogeneous group of disorders caused by structural and functional abnormalities in mitochondria leading to involvement of the nervous system and muscles as well as other organ systems. The peculiar genetic characteristics of mitochondrial DNA impart distinctive properties to these disorders. The pathophysiology is presented. The methods employed in making the correct diagnosis, the preoperative patient assessment and correction of metabolic dysfunctions and anaesthetic techniques used, are highlighted. The conditions are briefly reviewed and suggestions are made for the safe anaesthetic management of affected patients.     

Effect of acid-base management with or without carbon dioxide on plasma phosphate concentration during and after hypothermic cardiopulmonary bypass.

Variations of the phosphate concentration in plasma were studied in two groups of 12 patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB). Management of the acid-base status differed between the groups, according to whether or not carbon dioxide was added to the anesthetic gas mixture during hypothermia ('pH-stat' vs. 'alpha-stat' mode) following correction vs. no correction of pCO2 and pH for body temperature. Phosphate variations throughout the study were mostly within normal limits. From the start to the end of CPB, the mean rise in phosphate levels was 70% in the pH-stat group and 37% in the alpha-stat group (p < 0.001). During 3 hours after CPB, the phosphate values continued to rise by a mean of 25% in the alpha-stat patients, but fell by a mean of 3% in the pH-stat patients (p < 0.001). Such different phosphate patterns during and immediately after CPB may reflect profound metabolic disturbances and may be related to the altering effects of CO2 addition and respiratory acidosis on intracellular metabolic activity and phosphate homeostasis.     

Hemostatic activation and inflammatory response during cardiopulmonary bypass: impact of heparin management

BACKGROUND: Cardiac surgery involving cardiopulmonary bypass (CPB) leads to fulminant activation of the hemostatic-inflammatory system. The authors hypothesized that heparin concentration-based anticoagulation management compared with activated clotting time-based heparin management during CPB leads to more effective attenuation of hemostatic activation and inflammatory response. In a randomized prospective study, the authors compared the influence of anticoagulation with a heparin concentration-based system (Hepcon HMS; Medtronic, Minneapolis, MN) to that of activated clotting time-based management on the activation of the hemostatic-inflammatory system during CPB. METHODS: Two hundred elective patients (100 in each group) undergoing standard cardiac surgery in normothermia were enrolled. No antifibrinolytic agents or aprotinin and no heparin-coated CPB systems were used. Samples were collected after administration of the heparin bolus before initiation of CPB and after conclusion of CPB before protamine infusion. RESULTS: There were no differences in the pre-CPB values between both groups. After CPB there were significantly higher concentrations ( < 0.05) for heparin and a significant reduction in thrombin generation (25.2 +/- 21.0 SD vs. 34.6 +/- 25.1), d-dimers (1.94 +/- 1.74 SD vs. 2.58 +/- 2.1 SD), and neutrophil elastase (715.5 +/- 412 SD vs. 856.8 +/- 428 SD), and a trend toward lower beta-thromboglobulin, C5b-9, and soluble P-selectin in the Hepcon HMS group. There were no differences in the post-CPB values for platelet count, adenosine diphosphate-stimulated platelet aggregation, antithrombin III, soluble fibrin, Factor XIIa, or postoperative blood loss. CONCLUSION: Compared with heparin management with the activated clotting time, heparin concentration-based anticoagulation management during CPB leads to a significant reduction of thrombin generation, fibrinolysis, and neutrophil activation, whereas there is no difference in the effect on platelet activation. The generation of fibrin even in the presence of high heparin concentrations most likely has to be attributed to the reduced antithrombin III concentrations or reduced inhibition of clot-bound thrombin. Therefore, in addition to maintenance of higher heparin concentrations, monitoring and substitution of antithrombin III should be considered to ensure more efficient antithrombin activity during CPB.     

Influence of bispectral index monitoring on decision making during cardiac anesthesia

STUDY OBJECTIVE: To assess bispectral index (BIS) monitoring on decision making during cardiac surgery with cardiopulmonary bypass (CPB) by measuring the number of preset standardized comments with and without knowing the BIS value and by classifying the interventions following the BIS data. DESIGN: Prospective, randomized study. SETTING: University Hospital. PATIENTS: One hundred twenty-one patients scheduled for elective cardiac surgery (89 coronary patients, 24 valve replacement patients, and 8 valve replacement and coronary surgery). INTERVENTIONS: Patients were divided into 3 groups. An observing anesthesiologist recorded on a special form ("parallel" anesthesia record) data from the devices of the workstation and the BIS monitor. Conditions in which BIS monitoring was subjectively considered that might have been useful in anesthetic decision making were recorded as "events." In group A (36 patients), the responsible anesthesiologist had continuous access to BIS information. In group B (44 patients), intraoperative anesthetic management was "blinded" to BIS values, whereas in group C (41 patients), the anesthesiologist observing the BIS monitor was free to inform the attending anesthesiologist about the BIS score. The number of events was considered as negatively reflecting the quality of the clinical course of a patient. The reduction of events was considered as improvement in decision making. All patients received the same anesthetic regimen (propofol + remifentanil). Monitoring was equal in all cases. Mild hypothermic CPB was applied in 73 patients. Statistical analysis used 1-way analysis of variance, Student 2-tailed t test, and chi2 analysis. MAIN RESULTS: Patient demographic data, underlying pathology, operation performed, hypothermia application, times of anesthesia, duration of operation, and CPB were similar in the 3 groups. In group B, the BIS value was considered by the observer as useful to know in 220 events (5.00 +/- 1.58 per patient). In group C, the BIS value was considered by the observer as useful to know in 143 events (3.49 +/- 1.31 per patient, P < 0.001) and, at the same time, the attending anesthesiologist was informed about BIS. In 112 (78.3%) cases, measures were taken. Titration of anesthetic drugs was done in 79 (70.5%) patients, whereas titration of vasoactive drugs was done in 9 (8.0%) patients, titration of both in 13 (11.6%) patients, and other diagnostic or corrective actions in 11 (9.8%) patients. Distributions of BIS values did not differ statistically (39.19 +/- 10.32, 37.38 +/- 10.21, and 38.29 +/- 10.01 in group A, group B, and group C, respectively). "Zenith" and "nadir" BIS values after induction also did not differ statistically. Awakening and extubation times were similar in both groups. CONCLUSIONS: Subjectivity, although reduced as much as possible, can play a confining role in the value of our results. The usefulness of BIS monitoring is shown by the fact that BIS data resulted in corrective measures. Attending anesthesiologist's actions, based on BIS information, reduced the events in group C.