Normothermic cardiopulmonary bypass and cardioplegia reduce inotropic requirements and creatine kinase-MB after coronary artery bypass graft surgery

Purpose To determine whether normothermic cardiopulmonary bypass (CPB) and cardioplegia preserve myocardial function, reduce inotropic requirements, and reduce markers of myocardial ischemia following coronary artery bypass graft surgery (CABG). Methods We retrospectively reviewed the charts of 171 consecutive patients undergoing elective CABG by a single surgeon from April 1994 to December 1995. Hypothermic CPB with intermittent cold cardioplegia was used in 83 patients and normothermic CPB with intermittent warm cardioplegia in 88 patients. Demographic, surgical, hemodynamic, and inotropic requirements and laboratory data were reviewed. Results The duration of CPB was significantly shorter in the normothermic group (113±27vs 90±21 min;P<0.0001). After CPB the cardiac index was similar between groups, but significantly larger doses of both dopamine and dobutamine were required (8vs 5μg·kg⁻¹·min⁻¹,P<0.0001), and significantly more patients required norepinephrine administration in the hypothermic group (18%vs 6%;P=0.01). Postoperative peak values of creatine kinase MB fraction (CK-MB) were significantly lower in the normothermic group (80±60vs 55±54 IU·I⁻¹;P<0.0001). Conclusion Normothermic CPB and cardioplegia reduce inotropic requirements and CK-MB following CABG.     

Cerebral oxygenation is better during mild hypothermic than normothermic cardiopulmonary bypass

PURPOSE: Normothermic cardiopulmonary bypass (CPB) has been recently used in cardiac surgery. However, there is a controversy whether there is a difference in incidence of neurological disorder after coronary artery bypass graft (CABG) surgery between normothermic CPB and mild hypothermic CPB. In this study, we assessed the effects of normothermia and mild hypothermia (32 degrees C) during CPB on jugular oxygen saturation (SjvO2). METHODS: Twenty patients scheduled for elective CABG surgery were divided into two groups. Group 1 (n = 10) underwent normothermic (>35 degrees C) CPB, and Group 2 (n = 10) underwent mild hypothermic (32 degrees C) CPB. Alpha-stat blood gas regulation was applied. After inducing anesthesia, a 4.0 French fibre optic oximetry oxygen saturation catheter was inserted into the right jugular bulb to monitor SjvO2 continuously throughout anesthesia and surgery. RESULTS: The SjvO2 in the normothermic group was decreased at 20 (41.5+/-2.4%) and 40 min (43.8+/-2.8%) after the onset of CPB compared with control (53.9+/-5.4%, P<0.05). However, there was no change in SjvO2 in the mild hypothermic group during the study. No changes in jugular venous-arterial differences of lactate or creatine phosphokinase isoenzyme BB were observed in two groups during the study. CONCLUSIONS: Cerebral oxygenation, as assessed by SjvO2 was increased during mild hypothermic CPB than during normothermic CPB.     

Effects of mild hypothermic cardiopulmonary bypass on blood viscoelasticity in coronary artery bypass grafting patients

The purpose of this study was to determine the changes in blood viscoelasticity during and after coronary artery bypass grafting (CABG) and to identify correlations between blood viscoelasticity and patients' age, duration of cardiopulmonary bypass (CPB), and cross-clamp time. After Institutional Review Board approvals, patients (n = 10) who were subjected to mild hypothermic CPB were included in this study. Viscosity and elasticity were measured at strains of 0.2, 1, and 5 using a Vilastic-3 Viscoelasticity Analyzer. Arterial blood samples were collected pre-CPB, on normothermic CPB, hypothermic CPB, after rewarming, and after CPB. Viscosity and elasticity at strains of 0.2 and 1 were altered significantly during and after CPB compared to the pre-CPB (p < 0.01). In particular, elasticity of blood was diminished during normothermic bypass and could not be recovered after CPB (p < 0.01). Although there were strong correlations between blood viscoelasticity, duration of CPB, and cross-clamp time on normothermic CPB, only the patients' age showed a positive correlation between viscosity (r = 0.61, p = 0.05), and elasticity (r = 0.89, p < 0.001) after CPB. These results suggest that mild hypothermic CPB alters the blood viscoelasticity during and after CABG.     

Factors Associated with Postoperative Cognitive Dysfunction in Patients Undergoing Cardiac Surgery

Purpose Central nervous system complications continue to be major causes of morbidity and mortality after cardiac surgery. The purpose of this study was to identify the risk factors for postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery. Methods Eighty-eight patients scheduled for elective CABG were studied. After the induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb for the continuous monitoring of jugular venous oxygen hemoglobin saturation (SjvO₂). The hemodynamic parameters and arterial and jugular venous blood gases were measured during cardiopulmonary bypass (CPB). All patients underwent a battery of neurological and neuropsychological tests one day before the operation and at 6 months after the operation. Results The incidence of a cognitive decline at 6 months was 24/88 (27.3%). Greater age (P = 0.04), the presence of renal failure (P < 0.001), and diabetes mellitus (P < 0.001) were more frequent in the patients with postoperative cognitive dysfunction at 6 months after the operation than in patients without cognitive dysfunction. Age (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0–1.7; P = 0.04), diabetes mellitus (OR, 1.8; 95% CI, 1.2–2.4; P < 0.01), and presence of renal failure (OR, 2.8; 95% CI, 2.4–4.3; P < 0.01) were associated with cognitive impairment at 6 months postoperatively. However, there was no relationship between the presence of atherosclerosis in the ascending aorta and postoperative cognitive dysfunction after CABG surgery. Conclusions A greater age, diabetes mellitus, and renal failure were found to be risk factors for development of cognitive impairment at 6 months after CABG with CPB.     

Time course of changes in jugular venous oxygen saturation during hypothermic or normothermic cardiopulmonary bypass in patients with diabetes mellitus

BACKGROUND: Preexisting diabetic mellitus is a risk factor determining postoperative neurological disorders. The present study assesses the effects of normothermic and hypothermic cardiopulmonary bypass (CPB) on jugular venous oxygen saturation (SjvO2)in patients with preexisting diabetic mellitus. METHODS: Sixteen diabetic patients who underwent elective coronary artery bypass grafting surgery were randomly divided into two groups: Group DN (n=8, diabetic patients) underwent normothermic CPB (>35 degrees C), and group DH (n=8, diabetic patients) underwent hypothermic CPB (32 degrees C). Controls were 16 age-matched non-diabetic patients (normothemic group, CN: n=8; hypothemic group, CH: n=8). A 4.0 F fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb to continuously monitor SjvO2 values. Hemodynamic parameters and arterial and jugular venous blood gases were measured seven times. RESULTS: Cerebral desaturation, which was defined as SjvO2 values below 50%, was observed during normothermic CPB in diabetic patients (at the onset of CPB: 46+/-3%, at 20 min after onset of CPB: 49+/-3%, means+/-SD, respectively). No cerebral desaturation occurred in diabetic and control patients during hypothermic CPB. CONCLUSIONS: Patients with preexisting diabetes mellitus experienced cerebral desaturation during normothermic CPB.     

Oxygenation within the first 120 h following coronary artery bypass grafting. Influence of systemic hypothermia (32 degrees C) or normothermia (36 degrees C) during the cardiopulmonary bypass: a randomized clinical trial

BACKGROUND: Lung function is often impaired after cardiac surgery performed under cardiopulmonary bypass (CPB). Normothermic CPB has become more common, but it remains unknown whether it reduces post-operative lung function compared with hypothermic CPB. The aim of this study was to investigate oxygenation within the first 120 h after systemic hypothermia and normothermia under CPB. METHODS: Thirty patients undergoing coronary artery bypass grafting (CABG) were randomized to either hypothermic (32 degrees C) or normothermic (36 degrees C) CPB. Oxygenation was studied by a simple method for the estimation of intrapulmonary shunt and ventilation-perfusion (V/Q) mismatch pre-operatively and 4, 48 and 120 h post-operatively by changing Fio2 in four to six steps. V/Q mismatch was described with DeltaPo2 (normal values, 0-2.38 kPa). RESULTS: Shunt and V/Q mismatch (DeltaPo2) increased post-operatively in both groups (P<0.01), with no differences between the groups, and with the nadir values 48 h after surgery, i.e. shunt of 15% (5.8-25%) and DeltaPo2 of 3.0 kPa (0.8-14 kPa) [values given as median (range)]. CONCLUSIONS: Impaired oxygenation is prevalent and prolonged following CABG, with equal intensity after hypothermic and normothermic CPB.     

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.     

Normothermia: Ideal temperature for cardio pulmonary bypass

Background Hypothermic systemic perfusion has remained as an integral part of Cardiopulmonary bypass (CPB). Myocardial and Cerebral protection has been claimed as advantage of hypothermia. Normothermic CPB has been proved to be a safe alternative with good myocardial and cerebral protection. Material & Methods From March 2000 to Oct 2003, 346 cases were done under CPB with normothermic Systemic and myocardial perfusion. The age range being 7 months to 80 years with a mean of 43.69±20.41 years. The M:F ratio is 236∶110. (2.14∶1). The procedures performed include congenital heart disease, valve procedures, coronary artery bypass grafting and others. The following peri- and postoperative data were analysed statistically to evaluate the efficacy of Normothermic CPB. Total CPB time was 101.24±50.45 minutes, time interval between onset of CPB and aortic cross clamp was 5.23±2.31 minutes and release of cross clamp and off CPB was 7.34±3.85 minutes. Arrhythmia occurred during weaning off CPB in 5 (1.44%) patients. Ionotropes used during weaning from CPB in 93 (26.87%) patients of which 76 (21.96%) cases required only dopamine. Vasodilators required during weaning off CPB in 15 (4.33%) patients. Development of systemic hyperthermia during rewarming was in 1 (0.28%) case & difference of central and peripheral blood pressure in 7 (2.03%) cases. Postoperative ventilation duration was 5.04±4.79 hours. Total bleeding was 237±115 mls, re-exploration was done in 6 (1.73%) cases. Postoperative neurological complication in 2 (0.57%), renal impairment requiring dialysis in 2 (0.57%) & GI bleed in 2 (0.57%) cases. Mortality was in 6 cases of which 1 (0.28%) was due to inability to wean off from CPB. Conclusion We conclude normothermic systemic and myocardial perfusion during CPB is physiological, reduces morbidity and is a safe alternative to hypothermic CPB.     

Release of brain-specific creatine kinase and neuron-specific enolase into cerebrospinal fluid after hypothermic and normothermic cardiopulmonary bypass in coronary artery surgery

BACKGROUND: Coronary artery bypass (CABG) surgery is successfully managed with normothermic cardiopulmonary bypass (CPB) using warm blood cardioplegia. The lack of the protective effect of hypothermia, however, might make the central nervous system vulnerable. METHODS: Thirty-six patients were randomized into normothermic CPB (36-37 degrees C) (NTCPB group, n=18) and hypothermic CPB (28 degrees C) (HTCPB group, n=18) in order to examine whether normothermic or hypothermic CPB induces the release of the intracellular brain enzymes, creatine kinase (CK), its brain-specific isoenzyme (CK-BB), and neuron-specific enolase (NSE) into cerebrospinal fluid (CSF). In addition, clinical neurologic examination and neuropsychologic assessment were done preoperatively, 5 d and 11-23 mo postoperatively. RESULTS: One patient in each group suffered a stroke after surgery. Two patients in the normothermic group had minor neurologic complications. The cognitive decline after operation was similar in the NTCPB and HTCPB groups. CSF enzymes from normothermic and hypothermic CABG patients without gross neurologic complications were not significantly higher than CSF enzymes from orthopaedic reference patients. CABG patients with neurologic complications had higher enzyme concentrations. Cognitive decline after the operation correlated statistically significantly with CSF enzyme concentrations in the NTCPB group, but not in the HTCPB group. CONCLUSION: CABG operation without major neurologic complication does not induce the release of CK, CK-BB or NSE enzymes into CSF, irrespective of whether the CPB is normothermic or hypothermic.     

Clinical benefits of normothermic cardiopulmonary bypass on postoperative systemic metabolism

To evaluate the influence of body temperature during cardiopulmonary bypass (CPB) on postoperative systemic metabolism, 32 patients undergoing elective cardiac surgery were randomly assigned to either hypothermia (n = 16) or normothermia (n=16). Serial hemodynamic parameters and blood samples were obtained after surgery. CPB and operation times were significantly shorter and the platelet reduction ratio during CPB [= (platelets before CPB-platelets after CPB)/platelets before CPB] was significantly lower in normothermic patients than in hypothermic patients. The platelet reduction ratio was dependent on the minimum rectal temperature during CPB, the operation time, and the CPB time. In the early postoperative period, hypothermic patients had abnormally high systemic vascular resistance and a reduced cardiac index compared with the normothermic patients. There were no differences between 2 groups in postoperative hepatic and renal functions, changes in oxygen consumption, arterial-venous PCO₂ or arterial-venous pH gradient. This study suggested a beneficial influence of normothermic CPB on postoperative hemodynamics. Normothermic CPB was not associated with adverse effects on postoperative metabolic recovery.     

Normothermic cardiopulmonary bypass is beneficial for cognitive brain function after coronary artery bypass grafting--a prospective randomized trial.

BACKGROUND: Hypothermic and normothermic cardiopulmonary bypass (CPB) have resulted in apparently contradictionary cardiac and neurologic outcome. Cerebrovascular risk and cognitive dysfunction associated with normothermic CPB still remain uncertain. MATERIALS AND METHODS: In a prospective randomized study, we measured the effects of mildly hypothermic (32 degrees C, n=72) vs. normothermic (37 degrees C, n=72) CPB on cognitive brain function. All patients received elective coronary artery bypass grafting (mean age 62.1+/-6.3 years, mean ejection fraction 60.4+/-13%). Cognitive brain function was objectively measured by cognitive P300 auditory-evoked potentials before surgery, 1 week and 4 months after surgery, respectively. Additionally, standard psychometric tests ('trailmaking test A', 'mini-mental state') were performed and clinical outcome was monitored. RESULTS: Patients, operated with mild hypothermia, showed a marked impairment of cognitive brain function. As compared with before surgery (370+/-45 ms), P300 evoked potentials were prolonged at 1 week (385+/-37 ms; P<0.001) and even at 4 months (378+/-34 ms, P<0.001) after surgery, respectively. In contrast, patients operated with normothermic CPB, did not show an impairment of P300 peak latencies (before surgery 369+/-36 ms, 1 week after surgery 376+/-38 ms, n.s.; 4 months after surgery 371+/-32 ms, n.s.). Group comparison revealed a trend towards prolonged P300 peak latencies in the patient group undergoing mildly hypothermic CPB (P=0.0634) 1 week after surgery. Four months postoperatively, no difference between the two groups could be shown (P=n.s.) Trailmaking test A and mini mental state test failed to discriminate any difference. Five patients died (mild hypothermia n=3, normothermia n=2) postoperatively (cardiac related n=3, sepsis n=2). None of the patients experienced major adverse cerebrovascular events. CONCLUSIONS: Objective cognitive P300 auditory evoked potential measurements indicate, that subclinical impairment of cognitive brain function is more pronounced in patients undergoing mildly hypothermic CPB as compared with normothermic CPB for CABG.     

Postoperative atrial fibrillation: a comparison of off-pump coronary artery bypass surgery and conventional coronary artery bypass graft surgery

OBJECTIVE: To compare the incidence and pattern of onset of postoperative atrial fibrillation (AF) in patients undergoing coronary artery bypass graft (CABG) surgery with and without cardiopulmonary bypass (CPB). DESIGN: Retrospective, cohort-controlled study. SETTING: University hospital and tertiary referral center. PARTICIPANTS: A group of 108 consecutive patients who underwent primary off-pump coronary artery bypass (OP-CAB) surgery and a control group of 100 patients who underwent CABG surgery with CPB. All patients underwent surgery between January and September 1999. INTERVENTIONS: Patients in the OP-CAB surgery group were operated on by either of 2 surgeons. The CABG surgery group was drawn from the general pool of patients operated on by 1 of 10 surgeons. All patients underwent median sternotomy and received standard anesthesia and intensive care unit management for this institution. MEASUREMENTS AND MAIN RESULTS: Data from 99 OP-CAB surgery patients (data incomplete in 9 patients) were compared with data from 100 CABG surgery patients. General demographics were similar except the CABG surgery group received a higher mean number of distal anastomoses (3.3 v 3.0; p = 0.028) The incidence of AF was similar in both groups (OP-CAB surgery, 25% v CABG surgery, 18%; p = 0.228). The peak incidence of AF was postoperative day 2 in both groups. The median hospital length of stay was increased in patients developing AF. CONCLUSION: Avoiding CPB does not seem to reduce the incidence of postoperative AF in CABG surgery. The similar time distribution of onset of AF in OP-CAB surgery patients and CABG surgery patients may point toward a common cause.     

Effect of normothermic versus hypothermic cardiopulmonary bypass on cytokine production and platelet function

BACKGROUND: Proinflammatory cytokines and platelets play a key role in the systemic inflammatory response associated with cardiopulmonary bypass (CPB). The aim of this study was to evaluate the effects of both hypothermic and normothermic CPB on platelet activation, cytokine production, as well as their possible correlations. METHODS: Twenty patients who underwent CABG were randomly assigned into two groups receiving hypothermic and normothermic CPB. Blood samples were obtained through a venous catheter at 6 time points. The following parameters were measured: in vitro platelet aggregation, in vivo platelet activation, complete and differential blood cell counts, plasma soluble P-selectin levels, plasma IL-6, IL-1beta and TNFalpha levels. RESULTS: The results demonstrated that platelet abnormalities could be observed to a greater extent during hypothermic rather than normothermic CPB. The occurrence of in vivo platelet activation was suggested by the presence of a significantly increased percentage of platelets expressing CD62P on their surface, as well as by a decreased in vitro platelet aggregation induced by different agonists. Complete and differential blood cell counts showed no substantial decrease in platelet number without differences between groups. The results obtained also showed the presence of a significant release of sP-selectin during CPB, as well as a more pronounced increase of plasma sP-selectin levels in patients undergoing hypothermic compared to normothermic CPB. A comparison of cytokine levels demonstrated a significant elevation of plasma IL-6 levels during either hypothermic or normothenmic CPB, paralleling the neutrophil rise, while no differences were observed for TNF-alpha levels. Conversely, plasma IL-1beta levels were significantly elevated during hypothermic, but not during normothermic CPB. CONCLUSIONS: Hypothermic CPB is responsible for a greater platelet activation and endothelial dysfunction than normothermic CPB, leading to more profound changes in the hemostatic and inflammatory systems, which, in turn, might be responsible for the higher incidence of postoperative complications reported during hypothermic CPB.     

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.     

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.     

Renal dysfunction after cardiac surgery with normothermic cardiopulmonary bypass: incidence,risk factors,and effect on clinical outcome

Renal dysfunction is a frequent and severe complication after conventional hypothermic cardiac surgery. Little is known about this complication when cardiopulmonary bypass (CPB) is performed under normothermic conditions (e.g., more than 36 degrees C). Thus, we prospectively studied 649 consecutive patients undergoing coronary artery bypass surgery or valve surgery with normothermic CPB. The association between renal dysfunction (defined as a > or =30% preoperative-to-maximum postoperative increase in serum creatinine level) and perioperative variables was studied by univariate and multivariate analysis. Renal dysfunction occurred in 17% of the patients. Twenty-one (3.2%) patients required dialysis. Independent preoperative predictors of this complication were: advanced age, ASA class >3, active infective endocarditis, radiocontrast agent administration <48 h before surgery, and combined surgery. When all the variables were entered, active infective endocarditis, radiocontrast agent administration, postoperative low cardiac output, and postoperative bleeding were independently associated with renal dysfunction. The in-hospital mortality rate was 27.5% when this complication occurred (versus 1.6%; P < 0.0001). Furthermore, postoperative renal dysfunction was independently associated with in-hospital mortality (odds ratio, 4.1 [95% confidence interval, 1.3-12.8]). We conclude that advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration, as well as postoperative hemodynamic dysfunction, are more consistently predictive of postoperative renal dysfunction than CPB factors. IMPLICATIONS: We found that postoperative renal dysfunction was a frequent and severe complication after normothermic cardiac surgery, independently associated with poor outcome. Independent predictors of this complication were advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration (the only preoperative modifiable factor), as well as postoperative hemodynamic dysfunction.     

Transfusion and bleeding in coronary artery bypass grafting: an on-pump versus off-pump comparison

Blood transfusion rates in coronary artery bypass grafting (CABG) surgery using cardiopulmonary bypass (CPB) are typically higher compared with off-pump CABG (OPCAB). However, few studies have specifically examined intraoperative hemodilution as a contributing factor. The aim of this retrospective review was to compare the effect of using CPB or OPCAB on red blood cell (RBC) transfusion and postoperative bleeding. The lowest intraoperative hematocrit (Hct) was used as marker of intraoperative hemodilution. We reviewed the perioperative data of all isolated CABG patients at a metropolitan hospital from January 2003 to June 2005. Stepwise regression analyses were performed to determine whether CPB was an independent predictor of RBC transfusion, reoperation for bleeding, or postoperative chest drainage. Of a total of 1043 patients, there were 433 CPB and 610 off-pump cases. CPB use was not significantly related to increased RBC transfusions (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.63-1.52; p = .921) and was associated with a lower incidence of reoperations for bleeding (OR, 0.4; 95% CI, 0.2-0.8; p = .009). There was less chest drainage over the first 12 hours in patients undergoing CPB (p < .0001); however, total postoperative chest drainage was not significantly related to operative procedure (p = .122). The lowest documented intraoperative Hct was a significant factor in RBC transfusions (OR, 0.89; p < .0001), an increased reoperation rate for bleeding (OR, 0.9; p = .001) and more postoperative chest drainage (log10-transformed: at 12 hours, b = -0.009, p < .0001; total, b = -0.006, p < .0001). CPB is not an independent risk factor in the incidence of RBC transfusions and is not associated with increased postoperative bleeding for isolated CABG. However, intraoperative hemodilution is an independent risk factor, with a lower intraoperative Hct associated with more RBC transfusions, increased reoperations for bleeding, and increased postoperative chest drainage. Addressing intraoperative hemodilution is important in minimizing CPB-associated morbidities.     

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.     

Coronary artery bypass grafting by warm blood cardioplegia and normothermic cardiopulmonary bypass

Warm blood cardioplegia and normothermic cardiopulmonary bypass (CPB) have been used in coronary artery bypass grafting (CABG). The method of myocardial protection was intermittent combined antegrade and retrograde warm blood cardioplegia with terminal warm blood cardioplegia. We performed elective CABG in 30 patients above the age of 70 years (elderly group). These patients were compared with 30 patients below 70 years who underwent elective CABG (young group). No significant differences were observed about the preoperative data between two groups. No significant differences were obtained in the postoperative cardiac function, cerebral or renal complication between two groups. Warm blood cardioplegia and normothermic CPB were not associated with adverse effects on postoperative recovery in elderly as well as young patients. We may conclude that warm blood cardioplegia with normothermic CPB is a safe procedure for CABG in elderly as well as young patients.     

Hemodynamic and hormonal responses to hypothermic and normothermic cardiopulmonary bypass.

Normothermic cardiopulmonary bypass (CPB) is used in cardiac surgery at some institutions. To compare hemodynamic and hormonal responses to hypothermic (29 degrees C) and normothermic nonpulsatile CPB, 20 adults undergoing coronary artery bypass graft and/or aortic valve replacement were studied. Hemodynamic measurements and plasma hormone concentrations were obtained from preinduction to the third postoperative hour. The two groups were given similar amounts of anesthetics and vasodilators. Systemic vascular resistance increased only during hypothermic CPB, and heart rate was higher at the end of hypothermic CPB. Postoperative central venous pressure and pulmonary capillary wedge pressure were lower after hypothermic CPB. Oxygen consumption decreased by 45% during hypothermic CPB, did not change during normothermic CPB, but increased similarly in the two groups after surgery; mixed venous oxygen saturation (SvO2) was significantly lower during normothermic CPB. Urine output and composition were similar in the two groups. In both groups, plasma epinephrine, norepinephrine, renin activity, and arginine vasopressin concentrations increased during and after CPB. However, epinephrine, norepinephrine, and dopamine were 200%, 202%, and 165% higher during normothermic CPB than during hypothermic CPB, respectively. Dopamine and prolactin increased significantly during normothermic but not hypothermic CPB. Atrial natriuretic peptide increased at the end of CPB and total thyroxine decreased during and after CPB, with no difference between groups. This study suggests that higher systemic vascular resistance during hypothermic CPB is not caused by hormonal changes, but might be caused by other factors such as greater blood viscosity. A higher perfusion index during normothermic CPB might have allowed higher SvO2.