辅酶Q10在换瓣术中对心肌缺血再灌注损伤的作用

目的：探讨换瓣术ＣＰＢ中ＣｏＱ１０对心肌缺血再灌注损伤的作用。方法：将２４例行体外循环心脏瓣膜置换术患者分为两组。对照组应用冷停跳液灌注，试验组于心肌冷停跳液中加入辅酶Ｑ１０（２ｍｇ／ｋｇ）。观察血浆丙二醛（ＭＤＡ），心肌三磷酸腺苷（ＡＴＰ），能量储备（ＥＣ），心肌超微结构（线粒体计分）。结果：（１）再次证实存在心肌缺血再灌注损伤；（２）试验组较对照组减轻了心肌缺血再灌注过程中血浆ＭＤＡ升高；心肌能量保存较多；超微结构改变较轻。结论：冷停跳液内加入辅酶Ｑ１０能减少氧自由基产生，抗脂质过氧化，稳定细胞膜，改善心肌能量代谢，从而对瓣膜置换术中心肌缺血再灌注损伤产生一定保护作用。为较有效的心肌保护方法，应用于临床是可行的。     

Plasma hypoxanthine levels during crystalloid and blood cardioplegias: warm blood cardioplegia increases hypoxanthine levels with a greater risk of oxidative stress

BACKGROUND: Patients undergoing cardiopulmonary bypass (CPB) are subjected to severe oxidative stress, and frequently show evidence of acute lung injury post surgery. Associations between acute lung injury, oxidative stress, and aberrant ATP catabolism have been made and prompted us to consider whether the purine metabolites xanthine and hypoxanthine alter significantly during CPB when different types of cardioplegia are used. METHODS: Experimental design: retrospective follow up study on stored plasma samples from patients randomly selected to receive either warm blood, cold blood, or crystalloid cardioplegia. Setting: adult intensive care unit of post graduate teaching hospital. Patients: thirty-eight patients undergoing aortic valve replacement, with or without artery grafting. Operation was carried out by a single surgeon. Interventions: all patients received either a homograft aortic valve or a stentless porcine valve. RESULTS: No significant differences in xanthine levels at any time points during CPB, or between the different cardioplegic groups. Hypoxanthine levels were, however, significantly higher in patients receiving warm blood cardioplegia (74.84+/-16.715 microM, p=0.0151), and was most marked at time point 3 when the aortic cross clamp was released. Patients receiving crystalloid cardioplegia showed higher levels of hypoxanthine (44.56+/-10.16 microM) than those receiving cold blood cardioplegia (21.57+/-7.106 microM). CONCLUSIONS: Considering these data together, it suggests that aberrant ATP catabolism, characteristic of ischaemia/reperfusion, is further disturbed during warm blood cardioplegia leading to a marked increase in plasma hypoxanthine levels. This has the potential to further increase oxidative stress during CPB.     

Changes in intraerythrocyte electrolytes in open-heart cardiosurgical interventions

The changes of erythrocyte Na, K, C1, and Mg during open-heart surgery were studied in 10 patients undergoing aorto-coronary bypass and in 10 patients undergoing valvular replacement and chronically treated with digitalis and diuretics. The results showed: initial Mg levels lower in both groups of patients than in 10 healthy subjects utilized as controls (p less than .01); higher initial Na levels in patients treated with digitalis and diuretics than in controls (p less than .001); no electrolyte change during extracorporeal circulation; significantly increased Na values at the end of surgery and in the 1st postoperative day, that were probably caused by erythrocyte damage during CPB. The increase was observed following the CPB because of the slow rate of erythrocyte Na changes.     

Glutamine administration in patients undergoing cardiac surgery and the influence on blood glutathione levels

Background: Cardiac surgery with an extracorporeal circulation cardiopulmonary bypass (CPB) is characterized by an oxidative stress response. Glutathione (GSH) belongs to the major antioxidative defense. In metabolic stress, glutamine (GLN) may be the rate-limiting factor of GSH synthesis. Decreased GLN plasma levels were observed after various critical states. We evaluated, in patients undergoing open heart surgery with CPB, the effects of a peri-operative GLN supplementation on GSH in whole blood and assessed their influence on the Sequential Organ Failure Assessment score and the intensive care unit length of stay.
Methods: In this prospective, randomized, double-blinded study, we included 60 patients (age older than 70 years, ejection fraction <40% or mitral valve replacement) undergoing an elective cardiac surgery with CPB. We randomly assigned each subject to receive an infusion with either GLN (0.5 g/kg/day, group 1) or an isonitrogeneous, isocaloric, isovolemic amino acids solution (group 2) or saline (group 3).
Results: From the first post-operative day GLN plasma levels in group 1 were significantly increased compared with the other groups. With saline GSH the levels decreased significantly post-operatively compared with GLN. We observed a significant correlation between GLN delivery and GSH levels.
Conclusions: A peri-operative high-dose GLN infusion increased plasma GLN concentrations and maintained the GSH levels after cardiac surgery with CPB.     

Off-pump coronary artery bypass attenuates transient hepatocellular damage after myocardial revascularization

OBJECTIVE: Cardiopulmonary bypass (CPB) affects hepatocellular integrity and occasionally results in liver dysfunction after cardiac surgery. Performing coronary artery bypass graft surgery without CPB may help to reduce the risk of this complication and better preserve perioperative liver function. This study compared perioperative hepatocellular damage in patients undergoing on-pump and off-pump bypass surgery. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Patients scheduled for elective on-pump (n = 21) and off-pump (n = 17) coronary artery bypass surgery. MEASUREMENTS AND MAIN RESULTS: Liver function was assessed by serum levels of alcohol dehydrogenase (AD) and alpha-glutathione S-transferase (alpha-GST), which serve as more sensitive indices of hepatocellular injury than do conventional transaminases. Arterial blood was sampled at 6 stages: after induction of anesthesia (baseline); at the end of CPB in the on-pump group or on completion of the last distal anastomosis in the off-pump group; at the end of surgery; and 6 hours, 12 hours, and 24 hours after the end of anesthesia. The off-pump patients showed significantly lower increases in serum AD and alpha-GST levels than did the on-pump group. AD and alpha-GST values increased in the on-pump patients after the initiation of CPB and peaked at the end of surgery, with a return to baseline at 12 hours and 24 hours after the end of anesthesia. No clinically relevant liver dysfunction was observed in either group. CONCLUSIONS: CPB induced transient subclinical hepatocellular damage, whereas off-pump revascularization attenuated this damage.     

Preoperative autologous blood donation with cardiac surgery

BACKGROUND: Preoperative autologous blood donation is commonly used to reduce exposure to homologous blood transfusions among patients undergoing elective cardiac surgery. The purpose of this study was to ascertain how much volume of predonated autologous blood need to avoid of homologous blood transfusion in cardiac procedure. METHODS: One hundred twenty-eight patients underwent scheduled cardiac procedure between January 1998 and December 1999. Group 1: 400 ml predonated, operation without cardiopulmonary bypass (CPB) [n = 33], group 2: 800 ml predonated, operation without CPB (n = 23), group 3: 800 ml predonated, operation with CPB (n = 36), group 4: 1,200 ml predonated, operation with CPB (n = 36). Surgical procedures underwent only off-pump coronary artery bypass grafting (OPCAB) in groups 1 and 2. In groups 3 and 4 included coronary artery bypass grafting (CABG), valve replacement, CABG + valve replacement and atrial septal defect repair. RESULTS: There were no significant differences in mean body weight, mean preoperative hematocrit values or mean volume of intraoperative blood loss between groups 1 and 2. There were no significant differences in mean age, mean body weight, mean preoperative and postoperative day-7 hematocrit values, mean volume of intraoperative blood loss or mean CPB time between groups 3 and 4. The mean postoperative day-7 hematocrit value was significantly lower in group 1 than in group 2. Homologous blood transfusion was avoided in 63.6% of those with predonation of group 1 versus 100% at group 2 (p < 0.05), 86.1% at group 3 versus 94.4% at group 4 (p < 0.05). In group 3, all patients who underwent redo operation or CABG + valve replacement needed homologous blood transfusion. CONCLUSIONS: Autologous blood transfusion is effective for reducing the homologous blood requirement. It also seems that predonation of 800 ml may be sufficient to avoid homologous blood transfusion in cardiac surgery, however predonation of 1,200 ml is desirable in cases of redo operation or CABG + valve replacement.     

Effect of off-pump coronary surgery with right ventricular assist device on organ function and inflammatory response: a randomized controlled trial

BACKGROUND: Right ventricular assist devices (RVADs) have been proposed to improve exposure of the coronary arteries in off-pump surgery. In this study we investigated the impact of the A-Med RVAD on inflammatory response and organ function in patients undergoing coronary artery bypass grafting. METHODS: Sixty patients were prospectively randomized to conventional surgery with cardiopulmonary bypass (CPB) and cardioplegic arrest, beating heart surgery (off-pump), or beating heart surgery with the RVAD. Serial blood samples were collected postoperatively, for analysis of inflammatory markers, troponin I, protein S100, and free hemoglobin. Renal tubular function was assessed by measuring urine N-acetyl-glucosaminidase activity. RESULTS: No hospital deaths or major postoperative complications occurred in the study population. Interleukin-6, interleukin-8, C3a, and troponin I levels after surgery were significantly higher in the CPB group compared with the off-pump and RVAD groups. Free hemoglobin levels immediately after the operation, peak and total S100 levels, and N-acetyl-glucosaminidase activity were also significantly higher in the CPB group. CONCLUSIONS: Off-pump coronary revascularization, with or without RVAD, reduces inflammatory response, myocardial, neurologic, and renal injury, and decreases hemolysis when compared with conventional surgery with CPB and cardioplegic arrest.     

Markers of inflammation and oxidative stress in patients undergoing CABG with CPB with and without ventilation of the lungs: a pilot study

Cardiopulmonary bypass triggers systemic inflammation and systemic oxidative stress. Recent reports suggest that continuous ventilation during cardiopulmonary bypass (CPB) can affect the outcome of patients after cardiac surgery. We investigated the influence of lung ventilation on inflammatory and oxidative stress markers during coronary artery bypass graft (CABG) with CPB in 13 patients with (Group 2) or without (Group 1) ventilation of the lungs with small tidal volume (4 ml/kg). IL-10 and elastase in blood were elevated in both groups with a peak at the end of CPB (P<0.05) and returned to the baseline at 24 h after surgery. A significant increase in Trolox Equivalent Antioxidant Capacity (TEAC) was observed in both groups (P<0.05). Glutathione peroxidase (GPx) was significantly elevated 24 h after surgery only in Group 1 (P<0.05). There was a significant decrease in alpha-tocopherol 24 h after surgery in both groups (P<0.05). The inflammatory response observed during CPB is not directly influenced by continuous ventilation of the lungs with small tidal volumes. The modulation of antioxidant defense systems by ventilation needs further investigation.     

Serum Concentrations of Procalcitonin After Cardiac Surgery

Abstract Background and Aim: Monitorization of complications in patients underlying cardiac surgery may be difficult because cardiopulmonary bypass (CPB) can lead to a systemic inflammatory response syndrome because of exposure of blood to nonphysiological surfaces. The purpose of the study was to establish the baseline levels of procalcitonin (PCT) after cardiac surgery in our population in order to analyze a possible induction of the inflammatory response that might interfere with the diagnosis of infection by PCT. Methods: Serum samples from patients undergoing coronary artery bypass grafting or valve replacement were collected at the time of admission to intensive care unit, after surgery as well as in the first and second postoperative days. Patients were followed for the development of postoperative complications. PCT levels were measured by immunoluminometric assay. Results: The mean PCT values were significantly higher in the first postoperative day in all the groups except the control group. No increased PCT levels were found related neither to duration of CPB, nor to time of aortic clamping. Only patients who presented complications had significantly increased PCT values immediately after surgery (p = 0.004), in the first postoperative day (p < 0.0001), and in the second postoperative day (p < 0.0001) with respect to those who recovered uneventfully. Conclusions: A slight and transient increase in PCT levels was observed in the first postoperative day after cardiac surgery. Significant elevation of PCT was only observed when complications were present.     

盐酸戊乙奎醚对心脏瓣膜置换术患者CPB期间心肌NF-κB活性及血浆TNF-α水平的影响

目的 探讨盐酸戊乙奎醚对心脏瓣膜置换术患者CPB期间心肌NF-κB活性及血浆TNF-α水平的影响.方法 择期CPB下行心脏瓣膜置换术的患者45例,性别不限,年龄18～64岁,体重指数20～22 kg/m~2,NYHA心功能分级Ⅱ或Ⅲ级,随机分为3组(n=15):对照组(C组)和不同剂量盐酸戊乙奎醚组(P_1组和P_2组).P_1组和P_2组于手术开始即刻由中心静脉分别注射盐酸戊乙奎醚0.05和0.1mg/kg,C组给予等容量生理盐水.于CPB开始前和CPB期间测定心肌NF-κB的活性和血浆TNF-α及心肌肌钙蛋白I(cTnI)的浓度,并观察心肌组织病理学结果.结果 与CPB开始前比较,三组CPB期间血浆TNF-α和cTnI的浓度升高,心肌NF-κB活性增强(P＜0.01);与C组比较,P_1组和P_2组CPB期间血浆TNF-α和cTnI的浓度降低,心肌NF-κB活性减弱(P＜0.01);P_1组和P_2组CPB期间血浆TNF-α、cTnI的浓度和心肌NF-κB活性比较差异无统计学意义(P＞0.05).P_1组和P_2组心肌病理学损伤较C组减轻.结论 CPB前静脉注射盐酸戊乙奎醚0.05、0.1 mg/kg可减轻心脏瓣膜置换术患者心肌再灌注损伤,其机制与抑制心肌NF-κB活性和血浆TNF-α浓度的升高,从而减轻炎性反应有关.     

Can late survival of patients with moderate ischemic mitral regurgitation be impacted by intervention on the valve?

BACKGROUND: Ischemic mitral regurgitation is known to be associated with poor long-term outcome after coronary artery bypass grafting; however, our ability to alter that outcome with intervention on the valve is unclear. The decision to address the valve is most challenging for patients with only moderate mitral regurgitation, particularly with the popularization of off-pump surgery. We therefore reviewed early and late outcomes of patients undergoing revascularization with or without mitral valve surgery. METHODS: Patients with moderate mitral regurgitation undergoing revascularization with and without mitral surgery between January 1991 and September 1996 were identified retrospectively. Operative notes were reviewed and patients with structural valve disease excluded. Perioperative events and late outcomes as determined by telephone contact and search of the social security death index (survival data 97% complete) were compared. RESULTS: One hundred seventy-six patients with moderate mitral regurgitation underwent revascularization alone (n = 142) or with mitral repair or replacement (n = 34). Those undergoing revascularization alone had a higher serum creatinine, somewhat less mitral regurgitation, and lower New York Heart Association functional class preoperatively. Operative mortality was greater with valve surgery (21% vs 9%, p = 0.047). Actuarial survival of both groups at 5 years was similar (52% vs 58%, p = NS); however, when stratified by preoperative functional class, those with more advanced heart failure preoperatively had superior late survival if their mitral valve was intervened upon. CONCLUSIONS: The late survival of patients with ischemic mitral regurgitation undergoing coronary revascularization remains poor; however, intervention on the mitral valve appears to benefit those with symptomatic heart failure.     

1113例心脏瓣膜置换手术后急性肾损伤的临床分析

目的 研究不同类型心脏瓣膜置换手术后急性肾损伤（AKI）的发病情况及其危险因素。 方法 采用前瞻性队列研究。收集本院心外科2009年4月1日至2010年3月31日期间进行心脏瓣膜置换手术患者的临床资料,采用多因素回归方法筛选出各类心脏瓣膜置换患者术后发生AKI的危险因素。AKI诊断标准为48 h内Scr上升≥26.4 μmol/L或较基础值增加≥50%;和（或）尿量<0.5 ml?kg-1?h-1达6 h。结果 1113例瓣膜置换手术患者术后AKI发病率为33.24%,AKI患者住院病死率为6.49%,其死亡风险较非AKI患者增加5.373倍 （P < 0.01）。心脏瓣膜置换伴冠脉搭桥手术术后AKI发病率为75.00%,显著高于其它瓣膜置换手术类型（P < 0.01）。多因素非条件Logistic回归分析表明,年龄（每增加10岁）、男性、术中体外循环时间≥120 min以及心脏瓣膜置换合并冠脉搭桥手术是术后发生AKI的独立危险因素,OR值分别为1.455、2.110、1.768和2.994。 结论 AKI是心脏瓣膜置换手术后常见的严重并发症。心脏瓣膜置换合并冠脉搭桥手术术后更容易发生AKI。高龄、男性、术中体外循环时间≥120 min以及心脏瓣膜置换合并冠脉搭桥手术是心脏瓣膜置换术后发生AKI的独立危险因素。     

High oxygen concentration exacerbates cardiopulmonary bypass-induced lung injury

OBJECTIVE: To investigate the effect of ventilation with 100% oxygen on lung injury associated with surgery involving cardiopulmonary bypass (CPB). DESIGN: A prospective randomized study. SETTING: University hospital. PARTICIPANTS: Thirty patients undergoing coronary artery bypass graft surgery with CPB. INTERVENTIONS: Patients were randomized to receive 100% oxygen (Oxygen group) or 50% oxygen (Air group) throughout surgery. During CPB, patients' lungs in the Air group were flushed with air and in the Oxygen group with 100% oxygen. MEASUREMENTS AND MAIN RESULTS: Lung injury was evaluated by arterial oxygen tension-inspired oxygen concentration (PaO2-FIO2) ratio and cytokine levels (tumor necrosis factor-alpha and interleukin-8) in blood and bronchoalveolar lavage fluid measured before and after CPB. The lowest PaO2-FIO2 value was observed after 40 minutes following the completion of CPB in both groups. PaO2-FIO2 values 6 hours after CPB were not different from baseline in the Air group but remained lower (359+/-63 mmHg and 298+/-78 mmHg; p = 0.013) in the Oxygen group. Blood cytokine levels rose during surgery in both groups. Bronchoalveolar lavage levels of interleukin-8 did not change, whereas tumor necrosis factor-alpha increased only in the Oxygen group (p = 0.035). CONCLUSIONS: A significant decrease of oxygenation was observed in the early post-CPB period in both groups of patients, with delay in recovery in patients treated with 100% oxygen. A larger increase of the proinflammatory cytokines was found in patients treated with 100% oxygen. High oxygen concentrations during surgery with CPB should be used only when specifically required.     

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.     

Hydroxyethylrutosides during extracorporeal circulation: effect on erythrocyte deformability

The effect of hydroxyethylrutosides (HR) on erythrocyte deformability was studied in 13 adult patients subjected to extracorporeal circulation, in seven cases for single valve replacement and in six for coronary bypass operations. A single dose of 1.5 g HR was given by slow intravenous injection immediately before the cardiopulmonary bypass. The controls were 13 patients undergoing the same operations but without HR. In the HR-medicated valve group there was only 3% decrease in erythrocyte deformability following extracorporeal circulation, in contrast to a 41% (p less than 0.01) decrease in the control valve group. Among the coronary patients there was no such difference between the HR and the control groups, with deformability decreasing by 21 and 26%, respectively (both significant, p less than 0.05). HR administered before extracorporeal circulation thus had significant prophylactic effect on red cell deformability in patients undergoing valve replacement. Such beneficial action may improve nutritional blood flow, thereby reducing the number of postoperative complications in various organs. With higher doses and/or longer periods of administration, a favorable effect of HR might be possible also in patients subjected to coronary surgery.     

Epidural anesthesia may attenuate lipid peroxidation during aorto-femoral surgery

PURPOSE: To determine the effect of epidural anesthesia (EP) on oxygenation of the chronically ischemic limb in patients undergoing aorto-femoral bypass grafting and to assess whether it produces an alteration of lipid peroxidation and antioxidant status following revascularization. METHODS: In this prospective, randomized, single-blinded study 40 ASA II or III patients undergoing elective aorto-femoral bypass grafting were allocated to receive general anesthesia (group GA, n = 20), or epidural + GA (group EP, n = 20) during surgery. Femoral venous blood-gas status, activities of the protecting antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-px), glutathione reductase (GSH-rd), glutathione (GSH) and thiobarbituric acid-reactive substances (TBARS) as a marker of lipid peroxidation were determined in blood samples taken from the femoral vein at different intervals before and after revascularization. RESULTS: Before the induction of anesthesia in group EP, femoral venous PO(2) [mean (standard deviation), 95% confidence interval] increased after achieving an adequate level of blockade by EP extending to the dermatomal level of T6-8 [29.32 (4.6), 26.34-32.30 to 36.29 (4.6), 33.37-39.22 mmHg, P < 0.05]. Femoral venous PO(2) was similar in both groups thereafter. In the GA group a significant increase in erythrocyte TBARS was observed immediately after restoration of blood flow when compared with baseline values [221.32 (102), 148.35-294-29 to 337.26 (123) 248.99-425.53 nmol*g(-1) hemoglobin, P < 0.01] but not at any other moment. In the EP group TBARS did not increase throughout the study. Within group comparisons revealed no significant differences in GSH, GSH-px, GSH-rd and SOD. CONCLUSION: In patients with atherosclerotic aorto-iliac occlusive disease EP may possibly attenuate lipid peroxidation following revascularization but has no effect on antioxidant enzyme activities.     

Long-term Angiotensin-converting Enzyme Inhibitor Treatment Attenuates Adrenergic Responsiveness without Altering Hemodynamic Control in Patients Undergoing Cardiac Surgery

Background: The sympathoadrenal and the renin-angiotensin systems are involved in blood pressure regulation and are known to be markedly activated during cardiac surgery. Because unexpected hypotensive events have been reported repeatedly during anesthesia in patients chronically treated with angiotensin-converting enzyme (ACE) inhibitors, the authors questioned whether renin-angiotensin system blockade would alter the hemodynamic control through attenuation of the endocrine response to surgery and/or through attenuation of the pressor effects of exogenous catecholamines.

Methods: Patients with preserved left ventricular function undergoing mitral valve replacement or coronary revascularization were divided into two groups according to preoperative drug therapy: patients receiving ACE inhibitors for at least 3 months (ACEI group, n = 22) and those receiving other cardiovascular drug therapy (control group, n = 19). Anesthesia was induced using fentanyl and midazolam. Systemic hemodynamic variables were recorded before surgery, after anesthesia induction, during sternotomy, after aortic cross-clamping, after aortic unclamping, as well as after separation from cardiopulmonary bypass (CPB) and during skin closure. Blood was sampled repeatedly up to 24 h after surgery for hormone analysis. To test adrenergic responsiveness, incremental doses of norepinephrine were infused intravenously during hypothermic CPB and after separation from CPB. From the dose-response curves, pressor (defined as mean arterial pressure changes), and vasoconstrictor (defined as systemic vascular resistance changes) effects were analyzed, and the slopes and the dose of norepinephrine required to increase mean arterial pressure by 20% were calculated (PD20).

Results: At no time did the systemic hemodynamics and the need for vasopressor support differ between the two treatment groups. However, for anesthesia induction, significantly less fentanyl and midazolam were given in the ACEI group. Although plasma renin activity was significantly greater in the ACEI group throughout the whole 24-h study period, plasma concentrations of angiotensin II did not differ between the two groups. Similar changes in catecholamines, angiotensin II, and plasma renin activity were found in the two groups in response to surgery and CPB. The pressor and constrictor effects of norepinephrine infusion were attenuated markedly in the ACEI group: the dose-response curves were shifted to the right and the slopes were decreased at the two study periods; PD20 was significantly greater during hypothermic CPB (0.08 micro gram/kg in the ACEI group vs. 0.03 micro gram/kg in the control group; P < 0.05) and after separation from CPB (0.52 micro gram/kg in the ACEI group vs. 0.13 micro gram/kg in the control group; P < 0.05). In both groups, PD20 was significantly less during hypothermic CPB than in the period immediately after CPB.     

Aortic valve replacement. Aortic root versus coronary sinus perfusion with blood cardioplegic solution.

The role of retrograde coronary sinus cardioplegia in patients undergoing aortic valve replacement for aortic stenosis alone or in combination with myocardial revascularization has not been fully defined. Sixty-three patients undergoing elective aortic valve replacement received cold potassium blood cardioplegic solution via either the aortic root (36 patients) or the coronary sinus (27 patients). The patients were similar with respect to age, degree of aortic stenosis, ventricular function, severity of coronary artery disease, crossclamp time, completeness of revascularization, and mean volume and temperature of the infusion solution. The mean septal temperature and the release of myocardium-specific isoenzyme in the first 2 hours after crossclamp removal was higher in the retrograde group (p less than 0.008). Right and left ventricular function was preserved equally in the two groups, and volume-loading studies suggested improved diastolic performance in patients having retrograde cardioplegia. There were no differences between the two groups with respect to clinical outcome. We conclude that coronary sinus cardioplegia is as safe as aortic root perfusion for myocardial preservation in patients undergoing elective aortic valve replacement.     

Influence of a vital capacity maneuver on pulmonary gas exchange after cardiopulmonary bypass.

OBJECTIVE: To investigate the effect of a single, vital capacity breath (vital capacity maneuver [VCM]), administered at the end of cardiopulmonary bypass (CPB), on pulmonary gas exchange in patients undergoing coronary artery bypass graft surgery. DESIGN: Prospective, randomized, double-blind study. SETTING: University-affiliated hospital. PARTICIPANTS: Forty patients scheduled for elective coronary artery bypass graft surgery and early tracheal extubation. INTERVENTIONS: Patients were randomized to 1 of 2 groups. VCM patients received a VCM at the conclusion of CPB. Control patients received no VCM. MEASUREMENTS AND MAIN RESULTS: Intrapulmonary shunt (Q(S)/Q(T)), arterial oxygenation (PaO2), and alveolar-arterial oxygen gradients (P(A-a)O2) were measured after induction of anesthesia, CPB, intensive care unit (ICU) arrival, and extubation. The duration of postoperative intubation was recorded for each group. Q(S)/Q(T) increased significantly 30 minutes after CPB in the control group (15.7 +/- 1.8% to 27.4 +/- 2.6%; p = 0.01). In the VCM group, a small decrease in Q(S)/Q(T) occurred (16.1 +/- 2.0% to 14.9 +/- 2.0%). After ICU arrival and extubation, no significant difference in Q(S)/Q(T) existed between the 2 groups. With the exception of a higher P(A-a)O2 in the control group at induction of anesthesia, no differences in PaO2 or P(A-a)O2 were present between the 2 groups at any measurement interval. Patients who received a VCM were extubated earlier than the control group (6.5 +/- 2.1 hours v 9.4 +/- 4.2 hours; p = 0.01). CONCLUSION: The use of a VCM prevented an increase in Q(S)/Q(T) from occurring in the operating room. Although a VCM did not influence pulmonary gas exchange in the ICU, its application in the operating room appears to exert a beneficial effect on tracheal extubation times after cardiac surgery.