Cerebral emboli during cardiopulmonary bypass: effect of perfusionist interventions and aortic cannulas

Neuropsychological impairment is a very common complication of cardiopulmonary bypass (CPB). The principal cause of postoperative cognitive impairment is thought to be cerebral microemboli during CPB. We recently investigated the effects of perfusionist interventions and aortic cannulation techniques on cerebral emboli production during coronary bypass (CABG) surgery. Patients undergoing isolated CABG were monitored with continuous transcranial Doppler ultrasonography of the middle cerebral artery. Perfusionist interventions were defined as injections of drugs into the CPB circuit or acquisition of blood samples from the CPB circuit. Patients were randomized to receive either standard cannulation of the ascending aorta or cannulation of the distal aortic arch. Cerebral emboli were detected in all patients. The number of emboli per minute was markedly higher during perfusionist interventions than during other time periods. Patients with increased perfusionist interventions had worse neuropsychological outcomes. Cannulation of the distal aortic arch, with placement of the cannula tip beyond the cerebral vessels, resulted in significantly less cerebral emboli than cannulation of the ascending aorta. Perfusionist interventions are a common source of cerebral microemboli during CPB, and may contribute to postoperative neuropsychological impairment. Care should be taken to minimize the introduction of air into the bypass circuit during CPB. Provided it is performed safely, distal aortic arch cannulation is a useful technique for reducing cerebral emboli during cardiac surgery.     

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.     

Risk factors for cognitive dysfunction after coronary artery bypass graft surgery in patients with type 2 diabetes

OBJECTIVES: The mechanisms of postoperative cognitive dysfunction in patients with diabetes after coronary artery bypass grafting are not fully understood. We sought to determine which type 2 diabetes-related factors contributed to postoperative cognitive dysfunction at 7 days and 6 months after coronary artery bypass grafting. METHODS: One hundred eighty patients with type 2 diabetes who were scheduled for elective coronary artery bypass grafting were studied. As a control group, 100 patients without diabetes mellitus matched for age, sex, and educational level were examined. Hemodynamic parameters (arterial and jugular venous blood gas values) were measured during cardiopulmonary bypass. All patients underwent a battery of neurologic and neuropsychologic tests the day before surgery, 7 days after surgery, and 6 months after surgery. RESULTS: Age (odds ratio 1.5, 95% confidence interval 1.3-1.8, P = .03), presence of hypertension (odds ratio 1.8, 95% confidence interval 1.3-2.0, P = .01), jugular venous oxygen saturation less than 50% time (odds ratio 1.5, 95% confidence interval 1.1-2.0, P = .045), presence of ascending aorta atherosclerosis (odds ratio 1.5, 95% confidence interval 1.1-2.6, P = .01), diabetic retinopathy (odds ratio 2.0, 95% confidence interval 1.3-3.0, P = .01), and insulin therapy (odds ratio 2.0, 95% confidence interval 1.3-3.0, P = .05), were associated with cognitive impairment at 7 days. Insulin therapy (odds ratio 2.0, 95% confidence interval 1.3-3.8, P = .01), diabetic retinopathy (odds ratio 1.3, 95% confidence interval 1.2-2.9, P < .01), and hemoglobin A 1c (odds ratio 1.9, 95% confidence interval 1.3-3.1, P = .047) were associated with cognitive impairment at 6 postoperative months. CONCLUSIONS: Insulin therapy, diabetic retinopathy, and hemoglobin A 1c were factors in cognitive impairment at 7 days and 6 months after coronary artery bypass grafting in patients with type 2 diabetes.     

Cerebral microemboli during cardiopulmonary bypass: increased emboli during perfusionist interventions.

BACKGROUND: Microemboli to the cerebral circulation occur during cardiopulmonary bypass (CPB) and can contribute to postoperative neurologic dysfunction. Cerebral microemboli are known to occur during specific surgical interventions, but the source of a large proportion of emboli remains unexplained. We investigated whether interventions by the perfusionist could account for the appearance of cerebral microemboli. METHODS: Transcranial Doppler ultrasonography was used to continuously monitor the middle cerebral artery of 18 patients undergoing coronary artery bypass grafting. The CPB circuit consisted of a softshell venous reservoir, a hollow-fiber membrane oxygenator, and a 32-microm arterial filter. The mean embolic rate was calculated for three time periods: (1) during surgical interventions (aortic cannulation and decannulation, cross-clamp application and removal, CPB start and end, and start of cardiac ejection); (2) during perfusionist interventions (blood sampling and drug administration into the venous reservoir); and (3) during baseline (all other time periods during CPB). RESULTS: Microemboli were detected in all patients (mean +/- standard deviation, 207+/-142 per patient, median, 132). The number of emboli per minute was significantly (p < 0.001) higher during perfusionist interventions (6.9+/-4.5) than during surgical interventions (1.5+/-1.5) or during baseline (0.4+/-0.5). Drug administration resulted in a higher embolic rate than blood sampling. CONCLUSIONS: Interventions by the perfusionist account for a large proportion of previously unexplained cerebral microemboli during CPB. These emboli likely represent air bubbles that are not eliminated by the arterial line filter. Although further studies of additional types of CPB circuits are required, we believe that air in the venous reservoir should be avoided whenever possible to minimize the risk of neurologic injury.     

Pulmonary abnormalities after coronary arterial bypass grafting operation: cardiopulmonary bypass versus mechanical stabilization

BACKGROUND: Cardiopulmonary bypass has been implicated in causing poor pulmonary gas exchange postoperatively in patients undergoing coronary artery bypass grafting procedures. This randomized prospective study was conducted to determine whether patients undergoing coronary artery bypass grafting operations using cardiac stabilization and thereby avoiding cardiopulmonary bypass will have improved pulmonary function postoperatively. METHODS: Fifty-eight patients were randomized to one of two groups: coronary artery bypass grafting operation with stabilization or coronary artery bypass grafting operation with cardiopulmonary bypass. Preoperative and postoperative pulmonary gas exchange measurements were performed on intubated patients, including the arterial partial pressure of oxygen on 100% inspired oxygen, the alveolar-arterial oxygen gradient, and pulmonary shunt. Static and dynamic lung compliance measurements were performed postoperatively. Hemodynamic variables (including creatine kinase-MB and troponin levels), intubation time, postoperative bleeding, and blood transfusions were compared. RESULTS: Both study groups had a large decrease in arterial partial pressure of oxygen on 100% inspired oxygen (p < 0.0001) and a significant postoperative increase in the alveolar-arterial oxygen gradient (p < 0.0001). There was no statistical difference in the postoperative gas exchange between the two groups; however, the postoperative pulmonary shunt was significantly better in the stabilization group (24% versus 31%, p = 0.03). The patients were extubated in the intensive care unit earlier in the stabilization group (8.2 hours versus 9.2 hours, not significant). The mean static and dynamic lung compliance postoperatively was lower in the stabilization group, although not statistically significant (p = 0.06). CONCLUSIONS: Coronary artery bypass grafting operation using cardiac stabilization technique is safe and avoids the risk of cardiopulmonary bypass. The pulmonary gas exchange postoperatively is comparable to standard cardiopulmonary bypass procedures, but a reduced postoperative pulmonary shunt was seen in the stabilization group.     

The superiority of pulmonary function after minimally invasive direct coronary artery bypass

OBJECTIVE: We determined whether minimally invasive direct coronary artery bypass (MIDCAB) leads to excellent postoperative pulmonary function, and which contributes more to this--minithoracotomy or avoidance of cardiopulmonary bypass. METHODS: Pulmonary function 1 week before and 2 weeks after surgery was evaluated in 8 patients undergoing MIDCAB (Group M), 10 undergoing off-pump coronary artery bypass (Group O), and 12 undergoing conventional coronary artery bypass grafting (Group C). Parameters were adjusted by their predicted values and postoperative values were expressed as a ratio to preoperative ones. RESULTS: Only Group M maintained postoperative vital capacity and forced expiratory volume in 1 second close to the preoperative level and thus, showed significantly better recovery than Groups O and C. No significant difference was seen between Groups O and C. CONCLUSIONS: MIDCAB provides better recovery of pulmonary function early postoperatively than other procedures thanks to minithoracotomy rather than avoidance of cardiopulmonary bypass.     

A prospective, randomized study of the effects of prostacyclin on neuropsychologic dysfunction after coronary artery operation

This randomized, double-blind study was designed to evaluate the effect of prostacyclin (epoprostenol) on the incidence and severity of postoperative neuropsychologic dysfunction in patients undergoing coronary artery operation. Four days before operation and 1 week after operation, 100 patients having coronary artery bypass grafting underwent detailed neurologic and psychologic examinations and computed tomographic scans of the brain. The psychologic examination was repeated 2 months after operation. During cardiopulmonary bypass, all patients received 300 U/kg of heparin and then either buffer-diluent or prostacyclin (12.5 ng/kg/min from the time of heparinization until onset of cardiopulmonary bypass and 25 ng/kg/min during cardiopulmonary bypass). No deaths or major neurologic complications occurred in this series. Ninety-six patients completed the psychologic and neurologic evaluations 1 week after operation; 74 of these patients were evaluated psychologically 2 months after operation. Psychologic testing demonstrated similar declines in postoperative performance in both the prostacyclin-treated and the control groups; these changes were no longer present in either group 2 months after operation. Results of neurologic examinations and computed tomographic scans of the brain were unchanged. We conclude that the administration of prostacyclin during cardiopulmonary bypass in patients undergoing routine coronary artery operation has no effect on perioperative cognitive changes.     

Neurocognitive impairment and driving performance after coronary artery bypass surgery.

OBJECTIVE: Neurocognitive impairment is common after cardiac surgery but few studies have examined the relationship between postoperative neuropsychological test performance and everyday behavior. The influence of postoperative cognitive impairment on car driving has previously not been investigated. The purpose of this study was to evaluate neurocognitive function and driving performance after coronary artery bypass grafting (CABG). METHODS: Twenty-seven patients who underwent coronary artery bypass grafting with standard cardiopulmonary bypass technique and 20 patients scheduled for percutaneous coronary intervention (PCI) under local anesthesia (control group) were enrolled in this prospective study conducted from April 1999 to September 2000. Complete data were obtained in 23 and 19 patients, respectively. The patients underwent neuropsychological examination with a test battery including 12 tests, a standardized on-road driving test and a test in an advanced driving simulator before and 4-6 weeks after intervention. RESULTS: More patients in the coronary artery bypass grafting group (n=11, 48%) than in the percutaneous coronary intervention group (n=2, 10%) showed a cognitive decline after intervention (P=0.01). In the on-road driving test, patients who underwent coronary artery bypass grafting deteriorated after surgery in the cognitive demanding parts like traffic behavior (P=0.01) and attention (P=0.04). Patients who underwent percutaneous intervention deteriorated in maneuvering of the vehicle (P=0.04). No deterioration was detected in the simulator in any of the groups after intervention. Patients with a cognitive decline after intervention also tended to drop in the on-road driving scores to a larger extent than did patients without a cognitive decline. CONCLUSION: This study indicates that cognitive functions important for safe driving may be influenced after cardiac surgery.     

Early neurobehavioral disorders after cardiac surgery: a comparative analysis of coronary artery bypass graft surgery and valve replacement

OBJECTIVE: To analyze neurobehavioral disorders in the early postoperative period after valve replacement and coronary artery bypass graft (CABG) surgery. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Patients undergoing elective cardiac surgery with cardiopulmonary bypass; 42 patients in the valve replacement surgery group and 42 patients in the CABG surgery group, with both groups matched post hoc for age, sex, and preoperative cognitive status. MEASUREMENTS AND MAIN RESULTS: All subjects were investigated preoperatively as well as 2 and 7 days postoperatively with a comprehensive neuropsychologic and neuropsychiatric assessment. The groups did not significantly differ with respect to the incidence of postoperative neuropsychiatric disorders. Valve replacement surgery patients exhibited more severe neuropsychologic deficits and showed a slower recovery than patients who underwent CABG surgery. In both groups, postoperative neuropsychologic alterations were most marked in fluency, arithmetic, and memory performance. CONCLUSION: These results indicate that patients after valve replacement surgery have a higher risk of postoperative neuropsychologic alterations mainly attributable to temporal lobe dysfunction. This finding corresponds to a specific vulnerability of hippocampal structures to transient hypoxia.     

Postoperative hypoxia is a contributory factor to cognitive impairment after cardiac surgery

OBJECTIVE: Cognitive dysfunction and postoperative hypoxia are common sequelae of coronary artery bypass grafting, but there has been no study to determine whether there is any relationship between them. METHODS: Arterial blood gas measurements were performed before surgical intervention and on the second and fifth postoperative day, and neuropsychological assessments were performed before surgical intervention and 5 days and 3 months postoperatively by using a battery of 10 psychometric tests in 175 patients undergoing coronary artery bypass grafting. An estimate of overall performance on the battery at each assessment point was provided by a simple aggregate cognitive index score calculated from the mean z scores of 4 normally distributed test variables. Multiple regression analysis was performed by using the cognitive index score at day 5 as the dependent variable, with age, sex, duration of the operation, presence or absence of cardiopulmonary bypass, preoperative cognitive index score, and arterial oxygenation and percentage of saturation at day 5 as independent variables. RESULTS: The mean cognitive index score decreased significantly in 115 (66%) patients who agreed to neuropsychological test battery assessment on the fifth postoperative day but improved significantly beyond baseline at 3 months. Mean arterial oxygen tension and percentage of saturation decreased significantly 2 days after the operation and, although improving over the following 3 days, remained decreased at day 5. Decreased cognitive index scores at day 5 strongly predicted cognitive impairment at 3 months (r = 0.36). The only significant independent predictors of the day 5 cognitive index score in the multiple regression analysis were preoperative cognitive index score and arterial oxygenation tension at day 5 (r = 0.24, P <.03). CONCLUSIONS: We report a significant correlation between postoperative cognitive dysfunction and hypoxia 5 days after coronary artery bypass grafting. This finding might have therapeutic implications because early postoperative cognitive dysfunction influences long-term impairment.     

Off-pump coronary artery bypass grafting does not decrease the incidence of atrial fibrillation

BACKGROUND: Postoperative atrial fibrillation remains a significant source of morbidity after coronary artery bypass grafting. We reviewed the data on 2,569 patients to determine if the absence of cardiopulmonary bypass resulted in a lower incidence of atrial fibrillation. METHODS: All patients undergoing coronary artery bypass grafting without cardiopulmonary bypass from January 1, 1997 through June 30, 2001 were evaluated for postoperative atrial fibrillation. The data of 252 patients with no cardiopulmonary bypass (group 1) were reviewed and compared with three other patient groups. Group 2 consisted of 1,470 patients using cardiopulmonary bypass during the same study period. Group 3 consisted of 841 patients with a similar number of grafts as the study group but using cardiopulmonary bypass. Group 4 consisted of historical data for 847 patients operated on using cardiopulmonary bypass collected from January 1995 through December 1996. Prophylactic beta-blockade was instituted in January 1997. Groups 1 to 3 received this treatment, but group 4 did not. RESULTS: Group 1 had an incidence of atrial fibrillation of 8.8%. Groups 2, 3, and 4 had incidences of atrial fibrillation of 11.6%, 9.4%, and 28.0%, respectively. When compared with group 1, the incidence of atrial fibrillation in group 4 was statistically different (p <. 0001). CONCLUSIONS: Avoiding cardiopulmonary bypass did not aid the reduction of atrial fibrillation at our institution.     

Endotoxemia in coronary artery bypass surgery: a comparison of the off-pump technique and conventional cardiopulmonary bypass

OBJECTIVES: The endotoxemia associated with cardiac surgery is thought to be dominantly influenced by the use of cardiopulmonary bypass. The objectives of this study were to assess the relative contribution of cardiopulmonary bypass on endotoxemia apart from cardiac surgical access and to improve our understanding of the potential benefits of off-pump procedures. METHODS: Thirty patients undergoing coronary artery bypass grafting were followed up prospectively. The patients were divided into 2 equal groups: those who underwent bypass grafting through a sternotomy incision without cardiopulmonary bypass (off-pump group) and those who underwent bypass grafting through a sternotomy incision with cardiopulmonary bypass (CPB group). Blood sampling for endotoxin, lactate, and cardiac index measurements were performed during the following time points: (1) after sternotomy; (2) during the coronary occlusion period in the off-pump group and during aortic clamping in the CPB group; (3) after removal of the coronary occlusion sutures in the off-pump group and after removal of the aortic clamp in the CPB group; (4) 30 minutes after the completion of all distal anastomoses in the off-pump group and immediately after weaning from cardiopulmonary bypass in the CPB group; (5) 1 hour postoperatively; and (6) 12 hours postoperatively. RESULTS: Endotoxin and lactate levels were significantly (P <.05) lower in the off-pump group at all sampling time points, except after sternotomy. CONCLUSIONS: In conclusion, this study has shown that endotoxemia during coronary artery bypass surgery seems mainly to be associated with cardiopulmonary bypass procedure. The relatively lower endotoxin levels observed in off-pump surgery might contribute to improved postoperative recovery.     

A randomized study of carbon dioxide management during hypothermic cardiopulmonary bypass

Eighty-six patients undergoing coronary artery bypass graft (n = 63) or intracardiac (n = 23) surgery were randomly assigned with respect to the target value for PaCO2 during cardiopulmonary bypass. In 44 patients the target PaCO2 was 40 mmHg, measured at the standard electrode temperature of 37 degrees C, while in 42 patients the target PaCO2 was 40 mmHg, corrected to the patient's rectal temperature (lowest value reached: mean 30.1, SD 1.9 degrees C). Other salient features of bypass management include use of bubble oxygenators without arterial filtration, flows of 1.8-2.4 l.min-1.m-2, mean hematocrit of 23%, and mean arterial blood pressure of approximately 70 mmHg, achieved by infusion of phenylephrine or sodium nitroprusside. Neuropsychologic function was assessed with series of tests administered on the day prior to surgery, just before discharge from the hospital (mean 8.0, SD 5.8 days postoperatively, n = 82), and again 7 months later (mean 220.7, SD 54.4 days postoperatively, n = 75). The scores at 8 days showed wide variability and generalized impairment unrelated to the PaCO2 group or to hypotension during cardiopulmonary bypass. At 7 months no significant difference was observed in neuropsychologic performance between the PaCO2 groups. Regarding cardiac outcome, there were no significant differences between groups in the appearance of new Q-waves on the electrocardiogram, the postoperative creatine kinase-MB fraction, the need for inotropic or intraaortic balloon pump support, or the length of postoperative ventilation or intensive care unit stay. These findings support the hypothesis that CO2 management during cardiopulmonary bypass at moderate hypothermia has no clinically significant effect on either neurobehavioral or cardiac outcome.     

Drew-Anderson technique attenuates systemic inflammatory response syndrome and improves respiratory function after coronary artery bypass grafting

BACKGROUND: Cardiopulmonary bypass causes inflammatory reactions leading to organ dysfunction postoperatively. This study was undertaken to determine whether using patients' own lungs as oxygenator in a bilateral circuit (Drew-Anderson Technique) could reduce systemic inflammatory response to cardiopulmonary bypass, improving patients clinical outcome following coronary artery bypass grafting. METHODS: A prospective randomized controlled trial involving 30 patients, divided in two groups of 15 patients each, undergoing elective coronary artery bypass grafting, was undertaken. In the Drew-group bilateral extracorporeal circulation using patient's lung as oxygenator was performed. The other patients served as control group, where standard cardiopulmonary bypass procedure was used. RESULTS: Pro-inflammatory and anti-inflammatory mediators were measured. Peak concentrations of proinflammatory interleukin-6, interleukin-8, were significantly lower in 15 patients undergoing Drew-Anderson Technique compared with the concentrations measured in 15 patients treated with standard cardiopulmonary bypass technique. Differences in patient recovery were analyzed with respect to time of intubation, blood loss, intrapulmonary shunting, oxygenation, and respiratory index. In patients undergoing uncomplicated coronary artery bypass grafting procedures bilateral extracorporeal circulation using the patients' own lung as oxygenator provided significant biochemical and clinical benefit in comparison to the standard cardiopulmonary bypass procedure. CONCLUSIONS: This prospective randomized clinical study has demonstrated that exclusion of an artificial oxygenator from cardiopulmonary bypass circuit significantly decreases the activation of inflammatory reaction, and that interventions that attenuate this response may result in more favorable clinical outcome.     

Comparison of cerebral embolization during off-pump and on-pump coronary artery bypass surgery

BACKGROUND: Coronary artery bypass surgery with cardiopulmonary bypass carries a significant risk of perioperative brain injury. At least 1% to 5% will suffer a stroke, and at 3-months postoperatively approximately 30% are reported to have cognitive impairment assessed by neuropsychologic testing. In off-pump surgery cardiopulmonary bypass is not used and instrumentation on the ascending aorta is reduced. The main aim of this study was to assess if off-pump surgery reduces intraoperative cerebral embolization. METHODS: This was a prospective and randomized study of two comparable groups with regard to age, sex, years of education, preoperative cognitive functioning, and surgical characteristics. Fifty-two patients (29 off-pump) were monitored by the use of transcranial Doppler ultrasound for cerebral microembolization during surgery. Preoperative and postoperative clinical, cerebral magnetic resonance imaging, and neuropsychologic examinations were also carried out. RESULTS: There was a significant reduction in the number of cerebral microemboli during off-pump compared with on-pump surgery (16.3 [range 0 to 131] versus 90.0 [range 15 to 274], p < 0.0001). No significant difference with regard to the incidence of neuropsychologic performance (decline in 29% off-pump, 35% on-pump) or neuroradiologic findings at 3 months was found, and there was no association between the number of cerebral microemboli and cognitive outcome. CONCLUSIONS: This study clearly demonstrates that off-pump surgery leads to a reduction in intraoperative cerebral microembolization. A significant reduction in the number of off-pump patients with cognitive decline or ischemic brain lesions on cerebral magnetic resonance imaging could not be demonstrated in this relatively small patient population.     

Off-pump versus on-pump coronary artery bypass surgery and postoperative pulmonary dysfunction

OBJECTIVE: To investigate how off-pump coronary artery bypass grafting (CABG) affects postoperative pulmonary function when compared with on-pump CABG. DESIGN: Prospective clinical study. SETTING: University-affiliated teaching hospital. PARTICIPANTS: Adult patients (n = 39) undergoing elective coronary artery bypass surgery with or without cardiopulmonary bypass. INTERVENTIONS: Two groups of patients were compared: 19 consecutive patients undergoing off-pump CABG surgery and 20 consecutive patients undergoing conventional CABG surgery. MEASUREMENTS AND MAIN RESULTS: Pulmonary function tests (flow volume loops and lung volumes with plethysmography) were done preoperatively and 72 hours postoperatively. Arterial blood gases and PaO2/FIO2 were measured at various stages. Sequential chest x-rays were obtained and evaluated for pleural changes, pulmonary edema, and atelectasis. In both groups, PaO2/FIO2 ratios decreased progressively throughout the perioperative period, with no significant differences between the groups at any stage during the study. There was a significant decline in postoperative pulmonary function tests in both groups, but there was no difference between groups at 72 hours postoperatively. No differences were found in the time to extubation, atelectasis scores, or postoperative complications. CONCLUSIONS: Off-pump CABG does not confer major protection from postoperative pulmonary dysfunction compared with CABG surgery with CPB. Strategies for minimizing pulmonary impairment after CABG surgery should be directed to factors other than the use of CPB.     

冠状动脉搭桥术患者围手术期皮质醇昼夜人泌节律与神经心理状态的研究

目的研究冠状动脉搭桥术患者围手术期皮质醇昼夜节律变化与神经心理状态的关系.方法选择在低温体外循环或非体外循环下行冠状动脉搭桥术的男性患者40例,分为体外循环组和非体外循环组,每组20例.在术中特定时点和术后每3 h抽血1次持续到术后24 h.用放射免疫法检测血浆皮质醇的含量.于术前1 d、术后7～10 d及术后3个月,应用抑郁自评量表、焦虑状态/特性询问表和神经心理量表评估抑郁和焦虑程度以及认知功能.结果术后24 h体外循环组和非体外循环组分别有3例和7例患者表现为昼夜节律性分泌,其余患者则无昼夜节律性分泌.体外循环组和非体外循环组患者术后抑郁评分高于术前(P<0.01),而体外循环组患者术后7～10 d焦虑状态显著重于非体外循环组患者(P<0.05);体外循环组患者的数字广度测验(逆向)评分低于非体外循环组患者(P<0.05);斯特鲁字色干扰测验的改正反应和阻塞反应较非体外循环组患者显著减退(P<0.05).体外循环组患者术后皮质醇昼夜分泌节律紊乱与抑郁程度和斯特鲁字色干扰测验的改正反应相关, 而非体外循环组患者皮质醇分泌节律紊乱则与抑郁程度、数字广度测验(顺向)、符号数字模式测验和斯特鲁字色干扰测验的改正反应相关.抑郁程度与认知功能的某些项目相关.结论冠状动脉搭桥术患者围手术期皮质醇昼夜分泌节律紊乱,这种紊乱直接或通过情感状态间接与认知功能相关.     

A prospective, randomized study of endothelin and postoperative recovery in off-pump versus conventional coronary artery bypass surgery

OBJECTIVE: The objectives are 2-fold: (1). to serially determine endothelin (ET) levels in arterial vascular compartments in patients undergoing coronary artery bypass surgery using either cardiopulmonary bypass or off-pump techniques, and (2). to define potential relationships between endothelial levels and specific perioperative parameters of patient recovery. METHODS: In a prospective, randomized study, endothelin plasma content was measured from patients undergoing coronary artery bypass grafting using either off-pump techniques (OPCAB group, n = 25) or conventional cardiopulmonary bypass (CPB group, n = 25) before surgery, before and after coronary artery anastomosis, and 6 and 24 hours postoperatively. Specific indices of patient recovery including pulmonary artery pressures, ventilation requirement, and hospital stay were documented for patients in both study groups. RESULTS: Postoperative systemic arterial ET levels were significantly increased by 200% in the CPB group and 50% in the OPCAB group. ET levels remained significantly higher in the CPB group relative to the OPCAB group throughout the postoperative period of observation (p < 0.05). Pulmonary artery pressures, ventilation requirement, and hospital stay were significantly increased in patients in the CPB group. CONCLUSIONS: Postoperative ET levels were higher in patients who underwent CPB for coronary artery bypass surgery. Increased ET in the postoperative period may contribute to a more complex recovery from coronary artery bypass surgery in patients undergoing cardiopulmonary bypass.     

Centrifugal versus roller head pumps for cardiopulmonary bypass: effect on early neuropsychologic outcomes after coronary artery surgery

OBJECTIVE: To test the hypothesis that routine use of a centrifugal pump in the cardiopulmonary bypass circuit would result in a lower incidence of early neuropsychologic deficit when compared with conventional roller pumps. DESIGN: Prospective, randomized, double-blind. SETTING: University teaching hospital. PARTICIPANTS: Patients (n = 103) scheduled for elective coronary artery surgery. INTERVENTIONS: Patients were randomized into group C (centrifugal pump for cardiopulmonary bypass; n = 54) and group R (roller pump for cardiopulmonary bypass; n = 49). MEASUREMENTS AND MAIN RESULTS: A neuropsychologic test battery of 6 standard tests was administered before surgery and 5 days after surgery. An abnormal test result was defined as deterioration by >1 group SD from an individual's preoperative test performance. There were no significant differences between groups in preoperative or surgical parameters, intensive care unit stay, or hospital stay. There were no significant differences in the incidence of neuropsychologic deficit for patients with a deficit in at least 1 test (group C, 33%; group R, 51%; odds ratio, 0.48; 95% confidence interval, 0.22 to 1.06) or patients with a deficit in >/=2 tests (group C, 6%; group R, 18%; odds ratio, 0.26; 95% confidence interval, 0.07 to 1.03). In group R, there were more individual test deficits per patient than in group C (p = 0.04). CONCLUSION: There was no significant difference in the incidence of neuropsychologic deficit postoperatively with routine use of centrifugal pumps. The larger number of individual test deficits in the roller pump group suggest that further studies to assess the potential neuropsychologic benefits of the use of centrifugal pumps are warranted.     

Decreased cerebral emboli during distal aortic arch cannulation: a randomized clinical trial.

BACKGROUND: Cerebral emboli occur during cardiopulmonary bypass and are a principal cause of postoperative neurologic dysfunction. We hypothesized that arterial cannulation of the distal aortic arch, with placement of the cannula tip beyond the left subclavian artery, will result in fewer cerebral microemboli than conventional cannulation of the ascending aorta. METHODS: Patients undergoing coronary bypass surgery with a single crossclamp technique were randomized to receive cannulation of the distal aortic arch (n = 17) or standard cannulation of the ascending aorta (control group, n = 17). Trendelenburg positioning was used whenever possible. Cerebral emboli were quantified by continuous transcranial Doppler monitoring of the middle cerebral artery. RESULTS: Baseline demographics were similar for the 2 groups of patients, including cardiopulmonary bypass and crossclamp times. Cerebral microemboli were detected during cardiopulmonary bypass in all patients, with a range of 17 to 627 emboli. The total number of detected emboli was lower in the arch cannulation group (152 +/- 33, mean +/- standard error of the mean) than in the conventional cannulation group (249 +/- 35, P =.04). Embolization rates were lower in distal arch patients than in control patients during cardiopulmonary bypass (2.0 +/- 0.3 vs 4.2 +/- 0.9 per minute, respectively, P =.03). Reduction in cerebral emboli by distal arch cannulation was most pronounced during perfusionist interventions. CONCLUSIONS: Cannulation of the distal aortic arch results in less cerebral microembolism than conventional cannulation of the ascending aorta. Provided it is performed safely, distal arch cannulation may be an important surgical option for patients with severe atherosclerosis of the ascending aorta.