Metocurine kinetics in patients undergoing operations requiring cardiopulmonary bypass

Metocurine kinetics were determined in 10 patients undergoing operations requiring hypothermic cardiopulmonary bypass (CPB) and nine patients of similar age undergoing operations of similar duration but not requiring CPB. The metocurine dosage regimen was a bolus of 0.3 mg/kg given concomitantly with the commencement of an infusion at a rate of 0.04 mg/kg/hr; this regimen was designed to produce and maintain a plasma metocurine concentration associated with 95% depression of the twitch response. Metocurine kinetics were affected minimally by hypothermic CPB. The kinetic parameters including volumes of distribution at steady state of 0.35 L/kg and 0.34 L/kg and elimination clearances of 1.3 ml/min/kg and 1.1 ml/min/kg in the control and CPB groups, respectively, are in agreement with the results of others. Changes in neuromuscular blockade with the onset of CPB and the return to original blockade intensities with rewarming suggest a decreased sensitivity to the effects of metocurine at lower temperatures.     

Low systemic vascular resistance: differential diagnosis and outcome

OBJECTIVE: To determine the frequency and prognosis of the various causes of low systemic vascular resistance (SVR). DESIGN: Analysis of consecutive patients over a 5-year period; retrospective review. SETTING: Medical intensive care unit of a large university hospital. PATIENTS: Fifty-five patients with unexplained hypotension and a SVR less than 800 dynes x s/cm5. BACKGROUND: There are minimal data in the medical literature determining the frequency or outcome of patients with a low SVR that is unrelated to sepsis or the sepsis syndrome. We retrospectively reviewed and analyzed all hemodynamic data in a large university hospital over a 5-year period to determine the frequency and prognosis of the various causes of low SVR. Fifty-five patients with unexplained hypotension and a SVR less than 800dynesxs/cm5were identified. MAIN RESULTS: Twenty-two patients (Groups 1 and 2) met the criteria for sepsis syndrome. The mean SVR for this group was 445 +/- 168 dynesxs/cm5 with an associated mortality of 50%. Group 3 contained 20 patients with possible sepsis. Thirteen patients (Group 4) were nonseptic. The mean SVR of this group was 435 +/- 180 dynes x s/cm5 with an associated mortality of 46%. Extremely low SVR (below 450 dynes x s/cm5) was associated with a significantly higher mortality regardless of the etiology. CONCLUSIONS: At least a quarter of patients with hypotension and a low SVR have nonseptic etiologies. The patients with nonseptic etiologies have a similar mortality to septic patients. Clinicians should be aware of the wide spectrum of conditions that induce a low SVR.     

The use of the iSTAT portable analyzer in patients undergoing cardiopulmonary bypass

Objective. To evaluate the utility of the iSTAT blood analyzer, a bedside device for hematocrit, sodium, potassium, and glucose measurement during cardiopulmonary bypass (CPB).Methods. Forty patients scheduled for elective CPB were evaluated prospectively. In addition to using the iSTAT analyzer, blood samples were analyzed at four time points: following induction of anesthetic, 10 min. after initiation of CPB, 60 min. after initiation of CPB, and following heparin neutralization by protamine. Blood glucose concentration was measured by the hospital laboratory using a Kodak Analyzer and by a glucose meter, electrolytes were evaluated by the Kodak Analyzer and BGE (a device which is commonly used for satellite laboratory determinations of electrolyte and blood gas results), and hematocrit samples were measured by the hospital laboratory using an NE 8,000 and a centrifuge. The means and standard deviations of the differences between the methods were calculated.Results. The hematocrit values determined by the iSTAT machine, when adjusted for the level of total protein (according to manufacturer's directions), differed from the laboratory values by 0.53 = 1.46 percentage points. An alternative to measuring total protein and making the adjustment is simply adding 1 % to the hematocrit in the pre-CPB period and 3% on-CPB or post-CPB, which we found to yield values that differed from the laboratory by 0.52 ± 1.42 percentage points. For all four tests (hematocrit, sodium, potassium, and glucose) the iSTAT had a similar relationship to the laboratory values as did the other commonly used means (centrifuge, BGE, and glucose meter) of clinical evaluation.Conclusion. In summary, we found that in patients undergoing CPB, the iSTAT values agreed sufficiently well with standard laboratory values and that the iSTAT instrument can be relied upon for bedside measurements.Presented in part at the Annual Meeting of the Society of Cardiovascular Anesthesiologists, Philadelphia, PA, May 1995, and at the 70th meeting of the IARS, Washington DC, March 1996. Supported in part by a grant by iSTAT Corporation.     

Use of pre-operatively obtained platelets and plasma in patients undergoing cardiopulmonary bypass

Thirty-seven patients requiring cardiopulmonary bypass were prospectively studied and assigned to plateletpheresis or control groups in a non-randomized, non-blinded fashion according to apheresis exclusion criteria and our ability to perform apheresis within 24 hours of surgery. Patients were grouped by potential for hemostatic abnormalities following a risk point factor assignment established for this study. The study indicated improvement of hemostasis with autologous platelets and plasma as demonstrated by clinical and laboratory parameters and by overall blood component utilization. We conclude that pre-operative plateletpheresis in this patient population is feasible, safe, and effective.     

The use of the iSTAT portable analyzer in patients undergoing cardiopulmonary bypass

Objective. To evaluate the utility of the iSTAT blood analyzer, a bedside device for hematocrit, sodium, potassium, and glucose measurement during cardiopulmonary bypass (CPB).Methods. Forty patients scheduled for elective CPB were evaluated prospectively. In addition to using the iSTAT analyzer, blood samples were analyzed at four time points: following induction of anesthetic, 10 min. after initiation of CPB, 60 min. after initiation of CPB, and following heparin neutralization by protamine. Blood glucose concentration was measured by the hospital laboratory using a Kodak Analyzer and by a glucose meter, electrolytes were evaluated by the Kodak Analyzer and BGE (a device which is commonly used for “satellite laboratory” determinations of electrolyte and blood gas results), and hematocrit samples were measured by the hospital laboratory using an NE 8,000 and a centrifuge. The means and standard deviations of the differences between the methods were calculated.Results. The hematocrit values determined by the iSTAT machine, when adjusted for the level of total protein (according to manufacturer's directions), differed from the laboratory values by 0.53 = 1.46 percentage points. An alternative to measuring total protein and making the adjustment is simply adding 1 % to the hematocrit in the pre-CPB period and 3% on-CPB or post-CPB, which we found to yield values that differed from the laboratory by 0.52 ± 1.42 percentage points. For all four tests (hematocrit, sodium, potassium, and glucose) the iSTAT had a similar relationship to the laboratory values as did the other commonly used means (centrifuge, BGE, and glucose meter) of clinical evaluation.Conclusion. In summary, we found that in patients undergoing CPB, the iSTAT values agreed sufficiently well with standard laboratory values and that the iSTAT instrument can be relied upon for bedside measurements. Presented in part at the Annual Meeting of the Society of Cardiovascular Anesthesiologists, Philadelphia, PA, May 1995, and at the 70th meeting of the IARS, Washington DC, March 1996. Supported in part by a grant by iSTAT Corporation.     

Use of ranitidine in children undergoing cardiopulmonary bypass

Sixty children aged 6 wk to 10 yr were studied. The children were undergoing cardiopulmonary bypass (CPB) for correction of congenital heart defects. The aim of the study was to provide prophylaxis for stress-induced gastric ulceration by elevating the gastric pH to at least 3.5. Two infusion regimes of ranitidine were compared: 0.1 and 0.2 mg/kg.h. The period of study was from induction of anesthesia until the end of the first 24 h after surgery. Both regimes were effective. The 0.2-mg/kg.h infusion produced a significantly higher plasma concentration of ranitidine throughout the study period without any additional clinical benefit. Both regimes produced, within 3 h of cessation of CPB, a significant elevation in mean gastric pH to at least 5.3. This paper concludes that 0.1-mg/kg.h infusion of ranitidine is a safe and efficacious regime for the critically ill pediatric patient.     

Effects of N-acetylcysteine on pulmonary function in patients undergoing coronary artery bypass surgery with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has been implicated in causing poor pulmonary gas exchange postoperatively in patients undergoing coronary artery bypass grafting (CABG) procedures. In this prospective, randomized, double-blind, placebo-controlled study, we examined the pulmonary effects of N-acetylcysteine (NAC) in patients undergoing CABG. Twenty patients undergoing elective CABG and early tracheal extubation were randomized into two groups. Group I (ten patients) received a physiologic salt solution as a placebo in a continuous intravenous infusion for one hour before CPB and 24 hours after CPB; Group II (ten patients) received 100 mg/ kg NAC intravenously for one hour before CPB and 40 mg/kg/day at 24 hours after CPB. Perioperative hemodynamic and pulmonary data were recorded. Postoperative tracheal extubation was accomplished at the earliest appropriate time. The postoperative clinical course was similar in the two groups. Both groups exhibited significant postoperative increases in A-a oxygen gradient (p < 0.01), but patients in Group II exhibited significantly lower increases in postoperative A-a oxygen gradient (p < 0.006). Other hemodynamic and pulmonary data (pulmonary capillary wedge pressure, pulmonary vascular resistance (PVR), cardiac index (CI), shunt flow, dynamic lung compliance and static lung compliance) exhibited no differences between the groups. There was no significant difference in terms of intubation time. The malondialdehyde (MDA) increase in Group II following CPB was found to be significantly lower than in Group I (p = 0.043). This clinical study reveals that administration of NAC to patients undergoing elective CABG with CPB improves systemic oxygenation. There was no effect in other pulmonary parameters and in terms of intubation time.     

体外循环心脏手术患者围术期血清miR-208a表达变化

目的:探讨在体外循环下行心脏手术患者围术期血清中mi R-208a的变化。方法:采用实时荧光定量RT-PCR(RT-q PCR)检测20例在体外循环下行心脏瓣膜置换术患者围术期血清mi R-208a表达的变化,并与血清肌酸激酶同工酶(CK-MB)和心肌肌钙蛋白I(c Tn I)水平进行对比分析。结果:患者血清mi R-208a的表达水平在手术前很低,在主动脉阻断后开始升高(P<0.05),在主动脉开放后达到峰值(P<0.01),术后24 h下降,但仍较术前显著升高。皮尔森相关分析显示mi R-208a的表达与CK-MB和c Tn I变化呈正相关(P<0.05)。结论:血清mi R-208a可作为体外循环下心脏手术中心肌损伤的标志物。     

乌司他丁对小儿体外循环术后肺损伤的保护作用

目的探讨乌司他丁（Ulinastatin,UTI）对小儿体外循环（cardiopulmonary bypass,CPB）术后肺损伤的保护作用。方法先天性心脏病择期手术患儿27例被随机分为对照组（C组）和试验组（U组）。C组不给药,U组于麻醉诱导后、CPB开始时和主动脉开放时分别给予乌司他丁总量的1／3（15000万U／kg）。于麻醉诱导后（T1）、CPB结束即刻（L）以及CPB术后1h（T3）、12h（T4）和24h（T5）测动脉血浆中IL-8和中性粒细胞弹性蛋白酶（Neutrophil Elastase,NE）水平。于CPB术后1h、2h及4h测动脉血气,并监测CPB术后肺功能指标肺泡．动脉氧分压差（PA-aO2）、氧合指数（OI）。结果CPB结束即刻和术后1h时间点U组NE水平均显著低于C组对应值（P〈0．05）。CPB术后1h时U组IL-8显著低于C组（P〈0．05）。CPB术后1h U组的OI、PA-aO2显著低于C组（P〈0．05）。结论乌司他丁可通过抑制IL-8和NE的过度释放,对小儿CPB诱发的肺损伤起一定的保护作用。     

前列腺素E_1对体外循环心脏手术后肾功能的保护作用

目的探讨前列腺素E1(PGE1)对体外循环(CPB)心脏手术后肾功能的保护作用。方法将60例心功能Ⅱ、Ⅲ级的心脏瓣膜置换术患者随机分成2组,每组30例。实验组:PGE1以100 ng/mL加入预充液中。对照组只给等量生理盐水;观察两组CPB后4、12 h肾功能的变化。结果麻醉前两组患者年龄、体重、CPB时间、血肌酐(CR)、尿β2微球蛋白(β2-MG)、尿N-乙酰-β-D-氨基葡萄糖苷酶(NAG)值比较无显著差异(P>0.05);血CR两组CPB后与麻醉前比较无显著差异(P>0.05);尿β2-MG、尿NAG值CPB后较麻醉前高,且实验组明显低于对照组(P<0.05)。结论在体外循环心脏手术中应用PGE1对肾功能有保护作用。     

急性血小板分离对心脏直视手术患者血流动力学的影响

目的评价急性血小板分离对心脏直视手术患者血流动力学的影响。方法选择拟择期在心肺转流(CPB)下行心脏直视手术患者30例,ASA分级Ⅱ或Ⅲ级。采用随机数字表法,将患者随机分为两组:对照组(C组,n=15)和急性血小板分离组(APP组,n=15)。APP组在麻醉诱导及中心静脉置管后行APP,提取富血小板血浆保存至CPB结束鱼精蛋白中和肝素后输入,C组不行APP。记录APP组中心静脉置管成功后(T1)、APP开始后5min(T2)、10min(T3)、15min(T4)、20min(T5)和APP结束(T6)的心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)、心脏指数(CI)、每搏量指数(SVI)、全身血管阻力指数(SVRI)及每搏量变异度(SVV)等,C组在相应时间点记录上述血流动力学指标。结果与T1时比较,APP组T3～T6时CVP显著降低(P<0.05或0.01),T2～T6时SVV显著增高(P<0.01),其余指标差异无统计学意义;C组各项指标差异均无统计学意义。与C组比较,APP组T4～T6时CVP显著降低(P<0.01),T2～T6时SVV显著增高(P<0.01)。与C组比较,APP组患者去氧肾上腺素使用量和使用率显著增高(P<0.01)。结论 APP会减少心脏手术患者血容量,但并不明显减少患者心排血量,通过适当使用血管活性药,仍能保持血流动力学的稳定。     

Predictors for heparin resistance in patients undergoing coronary artery bypass grafting

Heparin resistance (HR) is a common event in cardiac operations. At present, no clear recognition of the risk factors for HR has been reached. The aim of this study was to determine a predictive model for HR, based on the preoperative patient's profile. Two hundred consecutive patients scheduled for elective coronary artery bypass operations were enrolled in a prospective trial. Demographics, type of preoperative anticoagulation therapy and preoperative coagulation profile were collected and statistically analysed with respect to the evidence of a HR. Heparin resistance was defined as at least one activated clotting time < 400 s after heparinization and/or the need for purified antithrombin III (AT-III) administration. With a multivariate analysis we could identify five predictors for HR: AT-III < or = 60%; preoperative subcutaneous heparin therapy; intravenous heparin therapy; platelet count > or = 300000 cells/mm3; age > or = 65 years. We conclude that HR is a predictable event. In the presence of all the risk factors, the likelihood of HR is 99%; in the absence of all of them, it is 10%. Predicting HR allows us to apply many possible therapeutic strategies.     

血管加压素对心肺转流术后血管麻痹综合征患者血流动力学的影响

目的评价血管加压素对心肺转流术(CPB)后血管麻痹综合征患者血流动力学的影响。方法选取CPB下心脏手术后发生血管麻痹综合征患者14例,分为去甲肾上腺素(NE)组(NE组)和血管加压素(AVP)组(AVP组)。NE组患者输注NE维持平均动脉血压>65 mmHg,当NE输注速率>0.4μg/(kg.min)则加用AVP 0.01～0.04 U/min;AVP组患者输注AVP0.01～0.04 U/min,必要时使用NE维持患者平均动脉血压>65 mmHg。于血管麻痹综合征诊断时(T1,基础值)、注药后24 h(T2)、48 h(T3)、72 h(T4)分别记录两组患者心率(HR)、平均动脉压(MAP)、平均肺动脉压(MPAP)、心排血量(CO)、肺毛细血管楔压(PCWP)、中心静脉压(CVP)及尿量,计算体循环血管阻力(SVR)及肺循环血管阻力(PVR)。并记录儿茶酚胺药物使用量及不良反应。结果两组患者年龄、体重、性别构成比,术前EF、术前治疗用药情况、CPB时间、主动脉阻断时间比较差异无统计学意义(P>0.05)。两组患者血压维持稳定。与NE组比较,AVP组SVR T2时增加;HR T2～3时显著降低(P<0.05);NE需要量T2～4明显降低(P<0.05);尿量明显增加(P<0.05)。结论 AVP可以改善CPB术后血管麻痹综合征患者的血流动力学。     

体外循环机在宫外孕手术自体血回输中的临床应用

近年来,随着输血技术的改进,常规的输血工作从理论上、观念上以及技术上都发生着重大的变革.目前临床用血日益增多,血源日趋紧张;另外,异体输血可带来不良反应(如输血反应等)和血源性传染病(如肝炎、艾滋病等),因此,自体血回输越来越受到重视,同时更受到病人、家属、术者的认可和接受.我院于1997年开始,对宫外孕大出血手术病人运用国产体外循环机进行术中血液回输,效果较满意.现报告如下.     

Dexamethasone reduces postoperative troponin levels in children undergoing cardiopulmonary bypass

OBJECTIVE: We previously demonstrated that dexamethasone treatment before cardiopulmonary bypass in children reduces the postoperative systemic inflammatory response. The purpose of this study was to test the hypothesis that dexamethasone administration before cardiopulmonary bypass in children correlates with a lesser degree of myocardial injury as measured by a decrease in cardiac troponin I release. DESIGN: A prospective, randomized, double-blind study. SETTING: The cardiac surgery operating room and intensive care unit of a pediatric referral hospital. SUBJECTS: Twenty-eight patients who underwent open-heart surgery for congenital heart defects. INTERVENTIONS: Patients received either placebo (group I, n = 13) or dexamethasone, 1 mg/kg iv (group II, n = 15), 1 hr before initiation of cardiopulmonary bypass. Plasma cardiac troponin I samples were obtained at three time points: immediately before study agent (sample 1), 10 mins after protamine sulfate administration after cardiopulmonary bypass (sample 2), and 24 hrs postoperatively (sample 3). MEASUREMENTS AND MAIN RESULTS: Mean cardiac troponin I levels (+/-sd) were significantly lower at sample time 3 in group II (dexamethasone; 33.4 +/- 20.0 ng/mL) vs. group I (control; 86.9 +/- 81.1) (p =.04). CONCLUSION: Dexamethasone administration before cardiopulmonary bypass in children resulted in a significant decrease in cardiac troponin I levels at 24 hrs postoperatively. We postulate that this may represent a decrease in myocardial injury, and, thus, a possible cardioprotective effect produced by dexamethasone.     

体外循环心脏术后死亡危险因素分析

目的 探讨体外循环心脏术后死亡可能的危险因素.方法 回顾性分析江苏省苏北人民医院从2005年3月至2006年6月体外循环心脏手术36例患者的临床资料.死亡组入选标准:(1)体外循环心脏手术患者;(2)术前心功能Ⅰ-Ⅲ级;(3)术前无其它脏器功能不全;(4)术后28 d内患者死亡;其中死亡组6人,存活组30例.调查内容包括:(1)术前因素:性别,年龄,术前诊断,术前NYHA分级,APACHEⅡ评分,左室舒张末内径.(2)术中因素:手术时间,主动脉阻断时间.(3)术后因素:出血量,机械通气时间,以及术后6h血流动力学及氧代谢指标:心率(HR),中心静脉压(CVP),肺动脉嵌顿压(PAWP),心输出量指数(CI),动脉血乳酸,动脉氧分压(PaO2),混合静脉血氧饱和度(SvO2),氧输送指数(DO2I),氧耗指数(VO2I),全身氧提取率(O2ext).所有数据应用SPSS10.0 for windows统计学软件包进行统计学分析.首先应用单因素相关分析,筛选出两组有显著差异的参数,然后再对这些参数进行多元回归分析,从中找出体外循环心脏术后死亡的独立危险因素.结果 单因素相关分析显示两组间APACHEⅡ评分,左室舒张末内径,主动脉阻断时间,机械通气时间,动脉血乳酸,SvO2等差异有统计学意义(P＜0.05).多元回归分析显示左室舒张末期内径,动脉血乳酸是体外循环心脏术后死亡的两个独立危险因素(P＜0.05).结论 左室舒张末期内径和动脉血乳酸可以作为评价体外循环心脏术后预后的重要指标.