Perioperative hyperinsulinaemic normoglycaemic clamp causes hypolipidaemia after coronary artery surgery

Background: Glucose–insulin–potassium (GIK) administration isadvocated on the premise of preventing hyperglycaemia and hyperlipidaemiaduring reperfusion after cardiac interventions. Current researchhas focused on hyperglycaemia, largely ignoring lipids, or othersubstrates. The present study examines lipids and other substratesduring and after on-pump coronary artery bypass grafting andhow they are affected by a hyperinsulinaemic normoglycaemicclamp. Methods: Forty-four patients were randomized to a control group (n=21)or to a GIK group (n=23) receiving a hyperinsulinaemic normoglycaemicclamp during 26 h. Plasma levels of free fatty acid (FFA), totaland lipoprotein (VLDL, HDL, and LDL)-triglycerides (TG), ketonebodies, and lactate were determined. Results: In the control group, mean FFA peaked at 0.76 (SEM 0.05) mmollitre^–1 at early reperfusion and decreased to 0.3–0.5mmol litre^–1 during the remaining part of the study. GIKdecreased FFA levels to 0.38 (0.05) mmol litre^–1 at earlyreperfusion, and to low concentrations of 0.10 (0.01) mmol litre^–1during the hyperinsulinaemic clamp. GIK reduced the area underthe curve (AUC) for FFA by 75% and for TG by 53%. The reductionin total TG was reflected by a reduction in the VLDL (–54%AUC) and HDL (–42% AUC) fraction, but not in the LDL fraction.GIK prevented the increase in ketone bodies after reperfusion(–44 to –47% AUC), but was without effect on lactatelevels. Conclusions: Mild hyperlipidaemia was only observed during early reperfusion(before heparin reversal) and the hyperinsulinaemic normoglycaemicclamp actually resulted in hypolipidaemia during the largestpart of reperfusion after cardiac surgery.     

Glucose,insulin and potassium for heart protection during cardiac surgery

Background. Coronary artery bypass grafting with hypothermiccardiac arrest and cardiopulmonary bypass (CPB) is associatedwith myocardial injury. Our study investigated whether an infusionof glucose, insulin and potassium (GIK) during elective coronaryartery bypass surgery decreases myocardial cell death. Methods. We measured cardiac troponin I (cTnI), a myofibrillarstructural protein, which is a sensitive and specific indicatorof myocytic injury. With ethics committee approval, 42 patientswere enrolled into a randomized, prospective, double-blindedstudy. In the GIK group, 500 ml of 50% dextrose solutioncontaining 100 IU insulin and potassium 80 mmol was infusedat the rate of 0.75 ml kg^–1 h^–1.Patients in the non-GIK group received 5% dextrose solutionat the same rate. Arterial blood samples were taken before inductionof anaesthesia, after removal of the aortic clamp and 6 and12 h after CPB. Results. In both groups there was an increase in cTnI concentration(P<0.05), which was greatest about 6 h after CPB. Atno time did the cTnI concentration differ between the two groups. Conclusion. The results suggest that GIK does not decrease theirreversible myocardial damage associated with routine coronaryartery bypass surgery. Br J Anaesth 2002; 88: 489–95     

乌司他丁对非体外循环冠状动脉旁路移植术病人围术期炎性反应的影响

目的观察乌司他丁对非体外循环冠状动脉旁路移植术(OPCABG)病人围术期炎性反应的影响。方法拟行OPCABG的病人24例,采用随机、双盲方法分为对照组(C组)和乌司他丁组(U组),每组12例。静脉注射咪达唑仑0.1mg/kg、芬太尼10～20μg/kg、哌库溴铵0.1mg/kg麻醉诱导后气管插管,机械通气,吸入1%～2%异氟烷、间断静脉注射芬太尼(2～5μg/kg,总量最高为50μg/ kg)、持续静脉输注哌库溴铵0.03～0.05mg·kg~(-1)·h~(-1)维持麻醉。U组麻醉诱导后开始恒速静脉输注乌司他丁6 000U/kg(30min内输完),然后以1 000 U·kg~(-1)·h~(-1)的速率持续静脉输注至手术结束。C组采用的同样方法输注等容量的生理盐水。分别在切皮前即刻(T_1)、冠状动脉全部吻合结束后0.5h (T_2)、术后2h(T_3)、6h(T_4)、18h(T_5)采集静脉血,测定血浆白细胞介素-6(IL-6)、IL-10、终末补体复合物(TCC)的浓度及CD11b/CD18的表达。结果与T_1比较,C组在T_(3,4)时IL-6浓度、T_3时IL-10浓度升高,T_(2-4)时CD11b/CD18表达升高,2组在T_2时TCC浓度均升高(P<0.05或0.01);与C组比较,U组在T_3时IL-6、IL-10浓度降低,在T_(2～4)时CD11b/CD18表达降低(P<0.05或0.01)。结论乌司他丁可在一定程度上抑制OPCABG病人围术期IL-6、IL-10浓度及CD11b/CD18表达的升高,具有减轻炎性反应的作用。     

不同剂量抑肽酶对非体外循环下冠状动脉搭桥术病人围术期炎性反应的影响

目的比较两种剂量抑肽酶对非体外循环下冠状动脉搭桥术(OPCAB)病人围术期白细胞介素-6(IL-6)、白细胞介素-10(IL-10)和肌钙蛋白I(TnI)的影响。方法39例OPCAB病人随机分为对照组(C组)、全量抑肽酶组(AH组)、半量抑肽酶组(AL组),每组13例。AH组:抑肽酶2．0×106 KIU溶于100 ml生理盐水中,于麻醉诱导后经30min恒速静脉输注完毕,然后以0．5×106 KIU／h速率静脉输注抑肽酶至手术结束;AL组:给药方法同上,抑肽酶剂量为AH组的一半。C组:输注同等容量生理盐水。分别在麻醉诱导后即刻(基础值)、冠状动脉血管吻合结束后0．5 h、术后2 h、6 h、18 h采集中心静脉血,测定IL-6、IL-10和TnI。结果与基础值相比,血浆IL-6、IL-10和TnI术后均升高(P<0．05)。与C组相比,两用药组血浆IL-6、IL-10和TnI水平术后降低,术后18 h胸液引流量减少(P<0．05);但两用药组间差异均无统计学意义。结论全量和半量抑肽酶均能抑制OPCAB病人围术期炎性反应,减轻心肌损伤,减少术后失血。对OPCAB病人半量抑肽酶为推荐剂量。     

Effect of low-dose ketamine on inflammatory response in off-pump coronary artery bypass graft surgery

Background: Off-pump coronary artery bypass graft surgery (OPCAB) is stillassociated with a marked systemic inflammatory response. Theaim of this study was to investigate whether pre-emptive, lowdose of ketamine, which has been reported to have anti-inflammatoryactivity in on-pump coronary artery bypass surgery, could reduceinflammatory response in low-risk patients undergoing OPCAB. Methods: In this prospective randomized-controlled trial, 50 patientswith stable angina and preserved myocardial function undergoingOPCAB were randomly assigned to receive either 0.5 mg kg^–1of ketamine (Ketamine group, n=25) or normal saline (Controlgroup, n=25) during induction of anaesthesia. Inflammatory markersincluding C-reactive protein (CRP), interleukin (IL)-6, tumournecrosis factor- (TNF-), and cardiac enzymes were measured previousto induction (T1), 4 h after surgery (T2), and the first andsecond days after the surgery (T3 and T4). Results: There were no significant intergroup differences in the serumconcentrations of the CRP, IL-6, and TNF- and cardiac enzymes.Pro-inflammatory markers and cardiac enzymes, except TNF-, wereall increased after the surgery compared with baseline valuesin both groups. Conclusions: Low-dose ketamine administered during anaesthesia inductiondid not exert any evident anti-inflammatory effect in termsof reducing the serum concentrations of pro-inflammatory markersin low-risk patients undergoing OPCAB.     

Circulatory effects of potassium, glucose and insulin following open-heart surgery

The cardiovascular effects of an acute infusion of potassium, glucose and insulin (PGI) were investigated in 10 subjects following valve replacement surgery. All required circulatory support with isoprenaline and no additional improvement in cardiac function could be demonstrated following PGI. Pressures in both atria rose out of proportion to the volume infused and there were biochemical changes which suggested that haemodilution had occurred. These findings were attributed to the administration of hypertonic dextrose solution and this also resulted in hyperglycaemia, glycosuria and an osmotic diuresis.     

The effects of glucocorticoid therapy on inflammatory responses to coronary artery bypass graft surgery

HYPOTHESIS: Delayed or reduced polymorphonuclear leukocyte (PMN) apoptosis may contribute to prolongation of systemic inflammation after cardiopulmonary bypass. BACKGROUND/OBJECTIVE: Preoperative administration of glucocorticoids has been used ostensibly to attenuate the systemic inflammation associated with cardiopulmonary bypass. Therefore, this study evaluated, in patients undergoing cardiopulmonary bypass, the efficacy of glucocorticoids in restoring peripheral blood PMN apoptosis and modulating PMN surface receptors (CD95, tumor necrosis factor receptor [TNFR]) known to be involved in proapoptotic or antiapoptotic signal transduction. DESIGN: Randomized control study. SETTING: Medical school and affiliated tertiary care hospital. PATIENTS: Thirteen patients undergoing coronary artery bypass grafting. INTERVENTION: Patients were randomly assigned to the control group (n = 7) or to receive 1 g of methylprednisolone sodium succinate on anesthetic induction (n = 6). MAIN OUTCOME MEASURES: Blood samples were drawn before induction, 20 minutes after sternotomy and bypass, immediately postoperatively, and on postoperative day 1. Isolated PMNs were incubated for 6 hours with or without the CD95 agonist CH 11. Polymorphonuclear leukocyte apoptosis was measured using propidium iodide-RNAase staining and flow cytometry. Levels of PMN cell-associated receptors (TNFR and CD95), cytokines (TNF-alpha, interleukin 6 [IL-6], IL-8, and IL-10), and soluble receptors (sTNFR1 and sTNFR2) were measured. RESULTS: In all 13 patients, spontaneous and Fas-mediated PMN apoptosis decreased more than 80% from baseline (P<.001) by postoperative day 1. Polymorphonuclear leukocyte CD95 increased (P<.003) by postoperative day 1 compared with baseline, whereas PMN TNFR was unchanged. Methylprednisolone administration did not modulate PMN apoptosis or immunocyte receptor expression; however, such treatment did decrease postoperative IL-6 secretion (P<.001) and increase postoperative IL-10 secretion (P<.001). CONCLUSIONS: The complications of major surgery include persistent inflammation, which can lead to multisystem organ failure. Polymorphonuclear leukocyte resistance to apoptosis may contribute to this process. A single preoperative dose of glucocorticoids did not effect PMN apoptosis or receptor phenotype.     

The effects of propofol on lipid peroxidation and inflammatory response in elective coronary artery bypass grafting

OBJECTIVE: To determine whether the antioxidant and anti-inflammatory properties of propofol confer benefit in adult patients undergoing elective coronary artery bypass grafting. DESIGN: Prospective, blinded, randomized, controlled clinical investigation. SETTING: Single-center, university teaching hospital and academic research laboratory. PARTICIPANTS: Twenty-one adult patients (11 control, 10 intervention) with chronic stable angina and normal ventricular function scheduled to undergo elective coronary artery bypass grafting. INTERVENTIONS: All patients received a standardized fentanyl-isoflurane anesthetic. Fifteen minutes before reperfusion, patients in the intervention group received a target-controlled infusion of propofol, continued for 4 hours after cross-clamp release. Patients in the control group received saline administered in a similar fashion. MEASUREMENTS: Serum concentration of malondialdehyde (MDA) (from systemic and coronary sinus blood); systemic concentrations of interleukins 4, 6, 8, and 10; and systemic leukocyte functions (respiratory burst, phagocytosis, and beta(2) integrin expression) were measured up to 36 hours after reperfusion. RESULTS: A high serum malondialdehyde concentration was detected in the coronary sinus in control patients, 10 minutes after reperfusion; serum malondialdehyde was not detected in the coronary sinus at this time in patients who received propofol (41.4 [15.6-1,150] micromol/L v 0, p = 0.004). Interleukin-8 concentrations increased 2 and 4 hours after reperfusion in the control group. Interleukin-6 concentrations were greater in the control group than the propofol group 4 hours after clamp release (289.1 [165.2-561] rhog/mL v 153.2 (58.2-280.3) rhog/mL, respectively, p = 0.003). Mean dose of propofol was 31.7 mg/kg during the study period. CONCLUSION: Clinically relevant concentrations of propofol may attenuate free radical-mediated and inflammatory components of myocardial reperfusion injury in patients undergoing elective coronary artery bypass graft surgery.     

Pre-treatment with hyperoxia before coronary artery bypass grafting - effects on myocardial injury and inflammatory response

BACKGROUND: In experimental studies, exposure to hyperoxia for a limited time before ischaemia induces a low-grade systemic oxidative stress and evokes an (ischaemic) preconditioning-like effect of the myocardium. We hypothesised that hyperoxia before cardioplegia could protect the myocardium against necrosis and stunning caused by ischaemia-reperfusion. METHODS: Forty patients undergoing coronary artery bypass grafting were randomly exposed to an oxygen fraction of 0.4 or > 0.96 in inspired air on an average of 120 min before cardioplegia. Blood for troponin I, creatine kinase-MB, lactate, glutathione and interleukin-6 was sampled from arterial and coronary sinus cannulae during 20 min of reperfusion. Additional arterial samples were drawn 60 min after declamping and in the first post-operative morning. The cardiac index and right and left ventricular stroke work indices were measured before sternotomy and up to 12 h post-operatively. RESULTS: Troponin I, creatine kinase-MB and lactate did not differ between the groups. Hyperoxic pre-treatment had no impact on the post-operative haemodynamic indices measured with the thermodilution pulmonary artery catheter. More oxidised glutathione was released in the hyperoxia group in the first minute of reperfusion (P = 0.015). Hyperoxic pre-treatment abolished the myocardial release of interleukin-6 during 20 min of reperfusion (P = 0.021 vs. controls). In the first post-operative morning, interleukin-6 was higher in the hyperoxia group [127.0 (86.0-140.0) vs. 85.2 pg/ml (66.6-94.5 pg/ml); P = 0.016]. Conclusions: Exposure to >96% oxygen before cardioplegia did not attenuate ischaemia-reperfusion injury of the heart in patients undergoing coronary artery bypass grafting. The only potentially beneficial effect observed was the decreased transmyocardial release of interleukin-6.     

Coronary artery spasm during coronary artery bypass surgery: its diagnosis, treatment and prevention

Between 1982 and 1983, we experienced four cases of hemodynamic collapse accompanied by an ST-segment depression in the ECG lead II, shortly after the cessation of cardiopulmonary bypass. The bypass graft flows monitored in these patients during the hemodynamic collapse episodes were remarkably low. In three cases, nitroglycerin (0.5-1 mg) was injected directly into the vein graft, which increased the graft flow suddenly, returned the ST-segment to the baseline, and improved the circulatory condition. Since 1984, however, diltiazem has been used in the cardioplegic solution and postoperative drip infusion. Due to the introduction of this drug, coronary artery spasm has not been seen in any of our patients since. These findings show that the monitoring of ST-segment changes and bypass graft flows are useful in the early diagnosis of coronary artery spasm after myocardial revascularization. Direct infusion of nitroglycerin into the vein graft is effective for the treatment of spasm, while diltiazem is useful in the prevention of coronary artery spasm incidental to myocardial revascularization.     

Coronary artery spasm during coronary artery bypass surgery: Its diagnosis,treatment and prevention

Between 1982 and 1983, we experienced four cases of hemodynamic collapse accompanied by an ST-segment depression in the ECG lead II, shortly after the cessation of cardiopulmonary bypass. The bypass graft flows monitored in these patients during the hemodynamic collapse episodes were remarkably low. In three cases, nitroglycerin (0.5–1 mg) was injected directly into the vein graft, which increased the graft flow suddenly, returned the ST-segment to the baseline, and improved the circulatory condition. Since 1984, however, diltiazem has been used in the cardioplegic solution and postoperative drip infusion. Due to the introduction of this drug, coronary artery spasm has not been seen in any of our patients since. These findings show that the monitoring of ST-segment changes and bypass graft flows are useful in the early diagnosis of coronary artery spasm after myocardial revascularization. Direct infusion of nitroglycerin into the vein graft is effective for the treatment of spasm, while diltiazem is useful in the prevention of coronary artery spasm incidental to myocardial revascularization.     

Myocardial circulatory and metabolic effects of isoflurane and sufentanil during coronary artery surgery

The global and regional coronary hemodynamic and myocardial metabolic effects of isoflurane administered intraoperatively as an adjunct to sufentanil were studied in seven of nine patients who experienced increased systemic arterial pressure while undergoing elective coronary artery bypass grafting. All patients were premedicated and maintained on their preoperative medications (beta-blockers, nitrates, Ca++ entry blockers) up to and including the morning of surgery. Systemic and pulmonary hemodynamics and global (coronary sinus, CS) and regional (great cardiac vein, GCV) coronary blood flows were measured, and blood samples were obtained for systemic and myocardial metabolic parameters: after induction with 30 mcg/kg of sufentanil and 0.12 mg/kg vecuronium (FIO2 1.0), but prior to incision (control); 5 min after sternotomy; and during ventilation with isoflurane-oxygen. Heart rate, cardiac output, stroke volume, and GCV/CS flow ratio did not change throughout the study. Neither global nor regional myocardial lactate production was detected in any patient at any time, and the electrocardiogram (lead II, V5) remained unchanged. In response to sternotomy, seven of nine patients experienced an increase in mean systemic arterial pressure of 20% or more (27 +/- 3% from control values), due to an elevation in systemic vascular resistance (30 +/- 5%). Coronary sinus (CS) and great cardiac vein (GCV) flows, as well as CS and GCV lactate extractions, were unchanged 5 min after sternotomy. Both global and regional myocardial oxygen extraction increased, while coronary venous oxygen content decreased. Isoflurane was administered in a dose that restored systemic arterial pressure to baseline values (inspired concentration 0.75-1.0%).(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of propofol on neutrophil function, lipid peroxidation and inflammatory response during elective coronary artery bypass grafting in patients with impaired ventricular function

Background. Coronary artery bypass grafting (CABG) with cardiopulmonarybypass elicits a potent reperfusion injury and inflammatoryresponse, more intense in patients with impaired myocardialfunction. Propofol has antioxidant properties which may attenuatesuch a response. Methods. In total, 27 patients with impaired left ventricularfunction undergoing CABG were randomly allocated to receiveeither target-controlled infusion propofol (P) or saline (S)immediately before aortic cross-clamp release until 4 h afterreperfusion. Troponin-I, Urinary 8-epi PGF-2 isoprostane, coronarysinus and systemic malondialdehyde concentrations, Interleukin-6(IL-6), -8 and -10 concentrations and leucocytes function studies(neutrophil respiratory burst, phagocytosis, CD-11b and CD-18expression) were measured. Results. Propofol decreased MDA coronary sinus concentrationat 1, 3 and 5 min after reperfusion (P<0.01); 60 min afterreperfusion a significant difference between the two groupsin systemic MDA concentrations was also seen. IL-6 concentrationincreases were significantly greater in Group S than Group P,4 h after reperfusion [1118 (1333) pg ml^–1 vs 228 (105)pg ml^–1, P<0.01]. Serum IL-8 concentrations did notincrease significantly in either group. Compared with baselinevalues IL-10 concentrations decreased after reperfusion butthe values were higher in the propofol group than in the controlgroup [22 (16) vs 11 (4) pg ml^–1, P<0.05]. No differencein leucocyte function or urinary isoprostane concentrationswas demonstrated. Conclusion. Propofol attenuates free-radical-mediated lipidperoxidation and systemic inflammation in patients with impairedmyocardial function undergoing CABG.     

The effects of aprotinin and steroids on generation of cytokines during coronary artery surgery.

OBJECTIVE: To compare the efficacy of aprotinin and methylprednisolone in reducing cardiopulmonary bypass (CPB)-induced cytokine release, to evaluate the effect of myocardial cytokine release on systemic cytokine levels, and to determine the influence of cytokine release on perioperative and postoperative hemodynamics. DESIGN: Prospective, randomized clinical trial. SETTING: University teaching hospital and clinics. PARTICIPANTS: Thirty patients undergoing elective coronary artery bypass graft surgery. INTERVENTION: Patients were randomly allocated into groups treated with aprotinin (n = 10) or methylprednisolone (n = 10) or into an untreated control group (n = 10). Aprotinin-treated patients received aprotinin as a high-dose regimen (6 x 10(6) KIU), and methylprednisolone-treated patients received methylprednisolone (30 mg/kg intravenously) before CPB. MEASUREMENTS AND MAIN RESULTS: Patients were analyzed for hemodynamic changes and alveolar-arterial PO2 difference (AaDO2) until the first postoperative day. Plasma levels of proinflammatory cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, IL-6, and IL-8) were measured in peripheral arterial blood immediately before the induction of anesthesia, 5 minutes before CPB, 3 minutes after the start of CPB, 2 minutes after the release of the aortic cross-clamp, 1 hour after CPB, 6 hours after CPB, and 24 hours after CPB; and in coronary sinus blood immediately before CPB and 2 minutes after the release of the aortic cross-clamp. The hemodynamic parameters did not differ among the groups throughout the study. After CPB, AaDO2 significantly increased (p < 0.05) in all groups. A significant decrease in AaDO2 was observed in aprotinin-treated patients at 24 hours after CPB compared with the other groups (p < 0.05). TNF-alpha level from peripheral arterial blood significantly increased in control patients 1 hour after CPB (p < 0.01) and did not significantly increase in methylprednisolone-treated patients throughout the study. In all groups, IL-6 levels increased after the release of the aortic cross-clamp and reached peak values 6 hours after CPB. At 6 hours after CPB, the increase in IL-6 levels in methylprednisolone-treated patients was significantly less compared with levels measured in control patients and aprotinin-treated patients (p < 0.001). In control patients, IL-8 levels significantly increased 2 minutes after the release of the aortic cross-clamp (p < 0.05), and peak values were observed 1 hour after CPB (p < 0.01). IL-8 levels in control patients were significantly higher compared with patients treated with aprotinin and patients treated with methylprednisolone 1 hour after CPB (p < 0.05). CONCLUSION: This study showed that methylprednisolone suppresses TNF-alpha, IL-6, and IL-8 release; however, aprotinin attenuates IL-8 release alone. Methylprednisolone does not produce any additional positive hemodynamic and pulmonary effects. An improved postoperative AaDO2 was observed with the use of aprotinin.     

Atrioventricular block in coronary artery bypass surgery: perioperative predictors and impact on mortality

Introduction

Disturbances of the cardiac conduction system are frequent in the postoperative period of coronary artery bypass surgery. They are mostly reversible and associated with some injury of the conduction tissue, caused by the ischemic heart disease itself or by perioperative factors.

Objective

Primary: investigate the association between perioperative factors and the emergence of atrioventricular block in the postoperative period of coronary artery bypass surgery. Secondary: determine the need for temporary pacing and of a permanent pacemaker in the postoperative period of coronary artery bypass surgery and the impact on hospital stay and hospital mortality.

Methods

Analysis of a retrospective cohort of patients submitted to coronary artery bypass surgery from the database of the Postoperative Heart Surgery Unit of the Sao Lucas Hospital of the Pontifical Catholic University of Rio Grande do Sul, using the logistic regression method.

Results

In the period from January 1996 to December 2012, 3532 coronary artery bypass surgery were carried out. Two hundred and eighty-eight (8.15% of the total sample) patients had atrioventricular block during the postoperative period of coronary artery bypass surgery, requiring temporary pacing. Eight of those who had atrioventricular block progressed to implantation of a permanent pacemaker (0.23% of the total sample). Multivariate analysis revealed a significant association of atrioventricular block with age above 60 years (OR=2.34; CI 95% 1.75-3.12; P<0.0001), female gender (OR=1.37; CI 95% 1.06-1.77; P=0.015), chronic kidney disease (OR=2.05; CI 95% 1.49-2.81; P<0.0001), atrial fibrillation (OR=2.06; CI 95% 1.16-3.66; P=0.014), functional class III and IV of the New York Heart Association (OR=1.43; CI 95% 1.03-1.98; P=0.031), perioperative acute myocardial infarction (OR=1.70; CI 95% 1.26-2.29; P<0.0001) and with the use of the intra-aortic balloon in the postoperative period of coronary artery bypass surgery (OR=1.92; CI 95% 1.21-3.05; P=0.006). The presence of atrioventricular block resulted in a significant increase in mortality (17.9% vs. 7.3% in those who did not develop atrioventricular block) (OR=2.09; CI 95% 1.46-2.99; P<0.0001) and a longer hospital stay (12.75 days x 10.53 days for those who didn''t develop atrioventricular block) (OR=1.01; CI 95% 1.00-1.02; P=0.01).

Conclusions

In most cases, atrioventricular block in the postoperative period of coronary artery bypass surgery is transient and associated with several perioperative factors: age above 60 years, female sex, chronic kidney disease, atrial fibrillation, New York Heart Association functional class III or IV, perioperative acute myocardial infarction and use of an intra-aortic balloon. Its occurrence prolongs hospitalization and, above all, doubles the risk of mortality.     

The effects of morphine and halothane anaesthesia on urine norepinephrine during and after coronary artery surgery

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - Urine concentrations and excretion rates of norepinephrine were measured in 28 patients anaesthetized with halothane or...     

Effects of perioperative central neuraxial analgesia on outcome after coronary artery bypass surgery: a meta-analysis

BACKGROUND: Perioperative central neuraxial analgesia may improve outcome after coronary artery bypass surgery due to attenuation of stress response and superior analgesia. METHODS: MEDLINE and other databases were searched for randomized controlled trials in patients undergoing coronary artery bypass surgery with cardiopulmonary bypass who were randomized to either general anesthesia (GA) versus general anesthesia-thoracic epidural analgesia (TEA) or general anesthesia-intrathecal analgesia (IT). RESULTS: Fifteen trials enrolling 1178 patients were included for TEA analysis. TEA did not affect incidences of mortality (0.7% TEA vs. 0.3% GA) or myocardial infarction (2.3% TEA vs. 3.4% GA). TEA significantly reduced the risk of dysrhythmias with an odds ratio of 0.52, pulmonary complications with an odds ratio of 0.41, and time to tracheal extubation by 4.5 h and reduced analog pain scores at rest by 7.8 mm and with activity by 11.6 mm. Seventeen trials enrolling 668 patients were included for IT analysis. IT had no significant effect on incidences of mortality (0.3% IT vs. 0.6% GA), myocardial infarction (3.9% IT vs. 5.7% GA), dysrhythmias (24.8% vs. 29.1%), nausea/vomiting (31.3% vs. 28.5%), or time to tracheal extubation (10.4 h IT vs. 10.9 h GA). IT modestly decreased systemic morphine use by 11 mg and decreased pain scores by 16 mm. IT significantly increased the incidence of pruritus (10% vs. 2.5%). CONCLUSIONS: There were no differences in the rates of mortality or myocardial infarction after coronary artery bypass grafting with central neuraxial analgesia. There were associated improvements in faster time until tracheal extubation, decreased pulmonary complications and cardiac dysrhythmias, and reduced pain scores.     

Glucose and lactate balances in heart and leg after coronary surgery: influence of insulin infusion

Glucose and lactate balances in leg (representing mainly skeletal muscle) and heart were studied 1 hour after aortocoronary bypass surgery and insulin treatment. Seventeen men were randomized to receive 25 U fast-acting insulin as a bolus injection, followed by continuous infusion of 1 U/kg b.w. for 1 hour, or to serve as controls. In the leg a small glucose uptake was found while the lactate balance was negative. During the study period the lactate release increased further in the control group. In the myocardium no significant extraction of glucose or lactate could be demonstrated. Insulin treatment resulted in a fivefold increment of leg glucose uptake and in significant myocardial glucose uptake. Myocardial lactate balance was also improved by insulin treatment, with fractional extraction increased from 6 to 21%. It is concluded that myocardial carbohydrate metabolism is restricted in the early period after cardiac surgery, and that this seems to result from insulin resistance induced by the surgical trauma.