早期乳酸清除率评估体外循环心脏手术患者预后

目的探讨早期乳酸清除率与体外循环心脏术后患者预后的关系。方法前瞻性观察并收集我院2006年3月至2010年2月体外循环心脏手术73例患者的临床资料。收集资料包括：（1）术前因素：性别、年龄、术前诊断、术前NYHA分级、APACHE11评分及左心室舒张末期内径。（2）术中因素：手术时间、主动脉阻断时间。（3）术后因素：术后出血量、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）、肺毛细血管嵌顿压（PAWP）、心输出量指数（CI）、动脉血乳酸、6h动脉血乳酸清除率、动脉血氧分压（PaO2）、混合静脉血氧饱和度（SvO2）、氧输送指数（DO2I）、氧耗指数（VO2I）及全身氧提取率（O2ext）。将患者分为存活组和死亡组,高乳酸清除率组（乳酸清除率〉30％）和低乳酸清除率组。首先应用单因素相关分析,筛选出两组有统计学意义的参数,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。结果高乳酸清除率组病死率[4．55％（2／44）]明显低于低乳酸清除率组[34．48％（10／29）],差异有统计学意义（X^2：11．889,P〈0．01）。单因素相关分析显示存活组与死亡组间APACHEⅡ评分[（16．9±2．9）分比（19．2±2．6）分,t=2．537],左心室舒张末期内径[（53．9±5．6）mm比（63．8±4．6）mm,t=5．847],主动脉阻断时间[（101．2±4-34．2）rain比（122．7±22．7）min,t=2．078],术后出血量[（464．0±158．8）ml比（603．2±159．5）ml,t=2．773],机械通气时间[（22．6±5．1）h比（28．8±5．2）h,t=3．857],动脉血乳酸[（3．5±1．3）mmol／L比（5．1±1．5）mmol／L,t=3．912],动脉血乳酸清除率[（38．8±17．4）％比（14．6±9．7）％,t：4．846],Sv02[（69．1±4．2）％比（59．2±6．9）％,t=5．847]差异有统计学意义（P〈0．05或P〈0．001）。多元回归分析昴示动脉向乳酸清除率、芹心宰舒张末期内径县体外循环心脏术后死亡的两个独立危险因素,优势比（OR）分别为7．773（95％CI1．364-44．306,P〈0．05）,15．186（95％CI2．758-83．162,P〈0．01）。结论早期血乳酸清除率可以作为评价体外循环心脏术后患者预后的重要指标。     

心脏瓣膜疾病患者术后出现心排血量减少的高危因素分析

目的:分析心脏瓣膜疾病患者术后出现心排血量减少的高危因素,以提高预后,改善心功能。方法:经诊断、纳入与排除后选取我院2018年1月-2019年1月收治的心脏瓣膜疾病手术患者120例,所有患者接受心脏瓣置换术,根据患者具体情况选择具体手术方法,术后密切观察患者生命体征,并给予相应得(的)辅助治疗。术前6个月患者接受飞利浦超声诊断检查,测量患者左室射血分数、左室舒张模内径、左心房内径、心排血量及术后心排血量,记录患者手术时间、体外循环转机时间、主动脉阻断时间、置换膜瓣数量。并分析心脏瓣膜疾病患者术后出现心排血量减少单因素与多因素。结果:120例患者中有24例心排血量减少,发生率20.00%,未减少96例(80%)。单因素分析结果显示,年龄、性别、术前左室舒张末内径、术前心胸比与术后排血量减少无关(P0.05),术前心功能分级、体外循环转机时间、置换膜瓣数量、术前左室输血分数、术中主动脉阻断时间、术前左室射血分数是排血量减少的单因素(P0.05)。术前心功能分级、体外循环转机时间、术前左室输血分数、术中主动脉阻断时间、术前左室射血分数是排血量减少的独立危险因素(P0.05),置换膜瓣与其无关。结论:重视脏瓣置换术前患者的术前心功能分级、体外循环转机时间、术前左室输血分数、术中主动脉阻断时间,选择合适的手术方式能有效预防心排血量减少,有利于提高预后。     

心脏术后混合静脉血氧饱和度监测的临床意义

目的:探讨36例心脏术后混合静脉血氧饱和度监测的临床意义。方法:36例病人分别于心脏术后半小时(Ⅰ组)及术后6～8h(Ⅱ组),分别测定动脉血PH值、氧分压(PaO2)、氧饱和度(SaO2)和混合静脉血pHv值、氧分压(PvO2)、氧饱和度(SvO2)及计算出氧利用率(O2ER)。并按SvO2均数分为≤65%(A组,n=11)、>65%(B组,n=25)两组。统计两组患者的ICU停留时间、在院期间并发症发生数。结果:心脏术后病人的氧耗明显增加,SvO2与O2ER呈明显的负相关,A组术后低心排、心律失常、低氧血症发生率及ICU停留时间和B组间有显著差异。结论:SvO2是衡量心脏术后病人组织氧供需平衡的良好指标。心脏术后早期SvO2水平可影响术后并发症的发生。     

连续性肾脏替代治疗患者动脉血乳酸和氧合指数监测的意义

目的:探讨血乳酸、氧合指数在脓毒症所致的多脏器功能失常综合征(MODS)患者行连续性肾脏替代治疗(CRRT)时疾病严重度监测中的意义.方法:对ICU 21例脓毒症所致MODS行CRRT治疗的患者,CRRT时行APACHEⅡ评分,监测动脉血气分析和乳酸值,记录比较CRRT治疗前后APACHEⅡ评分、动脉血乳酸水平及氧合指数的变化,以及死亡组和存活组动脉血乳酸水平和氧合指数的差异.结果:存活患者CRRT治疗前后动脉血乳酸含量、APACHEⅡ评分、氧合指数和乳酸清除率有显著性改变.死亡组由于病情重,其APACHEⅡ评分、动脉血乳酸含量、氧合指数治疗前后均无明显改善.存活组患者的初始APACHEⅡ评分、动脉血乳酸含量较死亡组低而氧合指数较死亡组高,乳酸清除率亦较死亡组高.结论:监测血乳酸浓度、血乳酸清除率及氧合指数可以较好评估脓毒症所致MODS患者CRRT治疗的疾病严重性和预后.     

动脉血和混合静脉血的氧监测在心脏术后中的应用

目的　研究 37例心脏术后病人的动脉血和混合静脉血的氧监测的临床意义。方法　 37例病人分别于术后入ICU时 (术后Ⅰ组 )、术后 6～ 18h(术后Ⅱ组 )及术后 8～ 2 4h(术后Ⅲ组 ) ,测定动脉血pH值、氧分压 (PaO2 )、氧饱和度 (SaO2 )和混合静脉血pHv值、氧分压 (PvO2 )、氧饱和度 (SvO2 )及计算出氧利用率 (O2 ER)。结果　心脏术后病人的氧耗明显增加 (P <0 0 1) ,SvO2 与O2 ER呈明显的负相关 ,术后Ⅰ组、术后Ⅱ组及术后Ⅲ组的r值分别为 - 0 9198、- 0 92 6 0及 - 0 916 6 (P值均 <0 0 0 1)。结论　SvO2 是衡量心脏术后病人组织氧供需平衡的良好指标。     

心脏瓣膜置换后早期住院患者死亡因素分析

背景：积极加强对高危患者心脏瓣膜置换前、中和置换后的处理,可降低心脏瓣膜置换后早期死亡率。 目的：分析心脏瓣膜病患者置换治疗后早期住院死亡的危险因素,提高手术治愈率。方法：回顾分析488例心脏瓣膜病患者行手术治疗作为临床资料;以置换后早期住院死亡为研究终点,采用单素及多因素Logistic回归方法分析置换后早期死亡的危险因素。结果与结论：488例心脏瓣膜置换患者中,置换后早期死亡27例,总死亡率5.5%。主要的死亡原因是低心排综合征、恶性心律失常、多器官功能衰竭。单因素分析显示：年龄≥60岁、心功能IV级、联合瓣膜手术以及同期冠状动脉旁路移植、左室射血分数≤50%、左室舒张末内径≥70 mm、体外循环时间≥120 min、主动脉阻断时间≥ 60 min与心脏瓣膜后死亡的发生具有相关性（P 〈 0.05）。多因素Logistic回归分析结果：年龄≥ 60岁、心功能IV级、瓣膜手术同期冠状动脉旁路移植、体外循环时间≥120 min、左室射血分数≤50% 、左室舒张末内径≥70 mm是影响心瓣膜置换后早期死亡的独立危险因素。重视围手术期处理,针对这些因素合理把握手术指征、选择合适的手术方式以及心肌保护,可以进一步降低这类患者手术并发症和病死率。     

无创正压通气对心脏手术后急性呼吸衰竭的疗效观察

目的：观察无创正压通气对体外循环条件下心脏手术后的急性呼吸衰竭的疗效。方法：对12例体外循环条件下进行的心脏直视手术后出现的急性呼吸衰竭的患者，经面罩选择压力支持S/T模式进行呼吸支持，观察治疗前后呼吸频率(R)、pH、动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、动脉血氧饱和度(SaO2)、混合静脉血氧饱和度(SvO2)及氧供(DO2)的变化情况。结果:呼吸机支持后，10例患者的R下降，PaO2、SaO2、SvO2及DO2上升，另2例患者无创正压通气失败，改为气管插管，行有创通气。结论：无创正压通气可有效地治疗部分心脏手术术后急性呼吸衰竭。     

静脉-静脉体外膜肺氧合支持治疗对体外循环心脏手术后难治性低氧血症患者预后的影响

目的 观察体外循环心脏手术后发生难治性低氧血症患者行静脉-静脉体外膜肺氧合(veno-venous extracorporeal membrane oxygenation, VV-ECMO)支持的疗效,探讨其发生院内死亡的影响因素。方法 体外循环心脏手术后发生难治性低氧血症患者12例,均行VV-ECMO支持治疗,治疗时间均≥24 h,观察患者VV-ECMO治疗期间发生插管处出血、术区出血、鼻出血、泵功能障碍、肺部感染等并发症发生情况及VV-ECMO撤机成功情况;比较VV-ECMO治疗前与治疗24 h后氧合指数、血浆乳酸水平、心率、平均动脉压、血管活性药物指数。根据患者存活出院情况分为死亡组4例和生存组8例,比较2组年龄、VV-ECMO治疗前急性生理学与慢性健康评估(Acute Physiology and Chronic Health EvaluationⅡ, APACHEⅡ)评分、VV-ECMO治疗24 h氧合指数等临床资料;采用多因素logistic回归分析体外循环心脏手术后难治性低氧血症患者行VV-ECMO治疗后发生院内死亡的影响因素。结果 12例患者VV-ECMO治疗时间为(1...     

高龄患者冠状动脉旁路移植术早期死亡危险因素分析

目的:比较高龄冠心病患者术后早期死亡的危险因素与非高龄患者的不同.方法:选择行单纯冠状动脉旁路移植手术患者820例,高龄组(年龄≥70岁)222例,对照组(年龄<70岁)598例.收集患者入院后的相关资料,危险因素分为术前变量、术中变量及术后变量,进行统计学分析.结果:影响高龄患者早期死亡的危险因素为:术前合并COPD(OR=7.653)、OPCAB(OR=6.785)、体外循环时间(OR=1.263).结论:对于高龄患者术前合并COPD及体外循环时间延长是高龄组患者术后早期死亡的独立危险因素:高龄患者更易从OPCAB中获益.     

个体化预测体外循环心脏术后严重高乳酸血症风险列线图模型的构建

目的 构建个体化预测体外循环心脏术后严重高乳酸血症风险列线图模型。方法 选取2020年1月至2022年12月于江苏省人民医院行体外循环心脏手术的患者作为为训练集,按照相同标准选取2023年1月至2023年6月的患者作为验证集。收集训练集患者的临床资料,根据严重高乳酸血症发生情况将患者分为严重高乳酸血症组和非严重高乳酸血症组。使用单因素和多因素Logistic回归分析体外循环心脏术后发生严重高乳酸血症的危险因素,并建立相关列线图预测模型。采用一致性指数(C-index)、校准曲线、受试者工作特征(ROC)曲线和决策曲线评估模型的预测效能。结果 训练集入组的469例体外循环心脏手术患者中,严重高乳酸血症组61例,非严重高乳酸血症组408例。两组ASA分级、NYHA心功能分级、体外循环时间、手术时间、急性肾损伤和呼吸机使用时间比较差异有统计学意义(P<0.05)。多因素Logistic回归分析显示,ASA分级为Ⅳ～Ⅴ级、NYHA心功能分级为Ⅲ～Ⅳ级、体外循环时间≥120 min、手术时间≥5 h、急性肾损伤和呼吸机使用时间≥24 h是体外循环心脏术后发生严重高乳酸血症的独立危险因素(P...     

完全性肺静脉异位引流术后低心排血量综合征的相关危险因素分析

目的分析完全性肺静脉异位引流（TAPVC）术后低心排血量综合征（LCOS）的危险因素。 方法选择从2014年1月至2018年1月在首都医科大学附属北京安贞医院小儿心脏中心进行TAPVC术的153例患儿，根据术后是否出现LCOS，将患儿分为LCOS组（50例）和无LCOS组（103例）。比较两组患儿术前、术中及术后的临床资料，采用Logistic回归分析TAPVC术后LCOS的影响因素。 结果LCOS组患儿围手术期病死率显著高于无LCOS组[22.0%（11/50）vs. 3.9%（4/103），χ² = 12.493，P < 0.001]。LCOS组和无LCOS组患儿年龄[3（1，5）个月vs. 5（2，12）个月，H = 2.722，P = 0.006]、体质量[5.2（4.5，6.0）kg vs. 6.0（5.0，8.0）kg，H = 3.519，P < 0.001]、术前左心室舒张末期内径[15（13，17）mm vs. 18（15，23）mm，H = 4.170，P < 0.001]、术前房间隔缺损大小[6（4，8）mm vs. 8（6，11）mm，H = 3.368，P = 0.001]、术前血氧饱和度[85（80，86）% vs. 85（82，87）%，H = 2.168，P = 0.030]、术中体外循环时间[100（75，137）min vs. 88（70，109）min，H = 2.459，P = 0.014]及是否延迟关胸（χ² = 4.484，P = 0.034）比较，差异均有统计学意义。将年龄、体质量、术前左心室舒张末期内径、术前房间隔缺损大小、术前血氧饱和度、延迟关胸及术中体外循环时间纳入Logistic回归分析，结果显示，术前左心室舒张末期内径[比值比（OR）= 0.851，95%置信区间（CI）（0.732，0.989），P = 0.035]、术前血氧饱和度[OR = 0.901，95%CI（0.829，0.979），P = 0.014]是行TAPVC术后出现LCOS的保护因素，而术中体外循环时间[OR = 1.012，95% CI（1.001，1.022），P = 0.028]是其危险因素。 结论应密切关注TAPVC患儿术前左心室舒张末期内径、血氧饱和度及术中体外循环时间，若发现LCOS的征象，应尽早干预以改善患儿的预后。     

Gastric tonometry and venous oximetry in cardiac surgery patients

OBJECTIVE: To determine the relationship between gastric intramucosal pH and several other indices of splanchnic perfusion in patients undergoing cardiopulmonary bypass. DESIGN: Prospective, single-arm study. SETTING: University Hospital. METHODS: Elective cardiac surgery patients (n = 8), free of hepatic disease, were studied. Before anesthetic induction, a triple-lumen, heparin-bonded fiberoptic catheter was inserted into the hepatic vein under fluoroscopic guidance. An identical catheter was inserted into the pulmonary artery. After endotracheal intubation, a nasogastric tube modified to permit measurement of gastric intramucosal pH was inserted into the stomach. Systemic oxygen delivery (DO2), and arterial, mixed venous, hepatic venous, and femoral venous blood gases and lactate concentrations were recorded at the following times: immediately before induction of anesthesia (time 1); during atrial cannulation (time 2); after 30 mins of hypothermic cardiopulmonary bypass (time 3); 15 mins after termination of cardiopulmonary bypass (time 4); and 1 hr after arrival in the ICU (time 5). Hepatic venous hemoglobin saturation (SO2) and mixed venous hemoglobin saturation (SvO2) were monitored continuously from times 1 to 5. Gastric intramucosal pH was recorded at times 2, 3, 4, and 5. The hepatic catheter was removed as soon as the last samples were collected in the ICU. RESULTS: The square of the weighted mean correlation coefficients (rw)2 for gastric intramucosal pH vs. hepatic venous lactate concentrations, gastric intramucosal pH vs. hepatic venous PO2, and gastric intramucosal pH vs. hepatic venous pH were (rw)2 = .50, (rw)2 = .58, and (rw)2 = .32, respectively. Systemic DO2, hepatic venous lactate concentrations, hepatic venous PO2, and hepatic venous pH were significant determinants in the multiple regression model for gastric intramucosal pH (r2 = .89). There were significant differences between SvO2 and hepatic venous SO2 at times 4 and 5. CONCLUSION: Gastric intramucosal pH may provide a minimally invasive way to monitor the adequacy of splanchnic DO2 in patients undergoing cardiopulmonary bypass. Additional data are necessary to determine whether low gastric intramucosal pH is truly a marker of supply-dependent oxygen uptake across the hepatosplanchnic vascular bed under these conditions.     

基于氧合指数指导下的进阶式肺康复训练结合俯卧位通气对重度老年ARDS患者心肺功能及血气指标的影响

目的 探究基于氧合指数指导下的进阶式肺康复训练结合俯卧位通气对重度老年急性呼吸窘迫综合征(ARDS)患者心肺功能及血气指标的影响.方法 选取128例重度老年ARDS患者,采用随机数字表法将患者分为对照组和观察组,每组64例,对照组给予俯卧位机械通气和肢体被动活动,观察组增加基于氧合指数指导下的进阶式肺康复训练,对比2组...     

Continuous monitoring of mixed venous oxygen saturation during aortic operations.

OBJECTIVE: To systematically analyze the changes in mixed venous oxygen saturation (delta SvO2) during aortic operations with tube, aortobi-iliac, and aortobifemoral grafts. DESIGN: Survey of consecutive patients. SETTING: Teaching community hospital. PATIENTS: Thirty-one patients (22 male, 9 female, mean age 67 +/- 10 yrs), undergoing elective operations for aortic aneurysms (n = 25) and aortoiliac occlusive disease (n = 6). INTERVENTIONS: SvO2 was recorded throughout the operation. Cardiac output, mean pulmonary arterial pressure, arterial oxygen saturation (SaO2), and arterial pH were measured before and immediately after the unclamping of the aortic graft. RESULTS: In all patients, unclamping the aorta resulted in a marked reduction of mean SvO2, with no change in the cardiac output or SaO2. The unclamping of tube grafts was associated with a significant reduction in arterial pH (p less than .01) and in SvO2 (p less than .001), when compared with unclamping of bifurcation grafts. A significant (p less than .05) increase in mean pulmonary arterial pressure was observed after unclamping the aorta in patients with tube grafts. Despite a longer clamp time, unclamping the second limb of a bifurcation graft resulted in a smaller delta SvO2, when compared with that observed after unclamping the first limb (12% vs. 6%; p less than .01). The delta SvO2 after unclamping limb II was only 2% in aortobifemoral grafts and 9% in aortobi-iliac grafts. CONCLUSIONS: Reperfusion via extensive pelvic and lumbar collaterals in patients with aortoiliac occlusive disease reduces the delta SvO2 after aortic unclamping. Monitoring the changes in SvO2 during different types of aortic reconstruction helps to define precisely the physiologic alterations that occur in the course of these operations.     

Is body surface area still the best way to determine pump flow rate during cardiopulmonary bypass?

For over four decades, pump flow rate during cardiopulmonary bypass (CPB) has been estimated using body surface area (BSA). As patients presenting for heart surgery are increasingly obese, this approach may no longer be appropriate and other estimates of systemic metabolism should be used, such as body mass index and lean body mass. Mixed venous oxygen saturation (SvO2) is a robust and independent estimate of the global efficacy of CPB. The aim of this study was to determine which factors, including body surface area, body mass index and lean body mass, best predict SvO2 during CPB. Forty-eight patients undergoing elective cardiac surgery requiring CPB were studied. Patients' height, weight and skinfold thickness at four sites (biceps, triceps, subscapularis and suprailiac) were measured. Body surface area, lean body mass and body mass index were then calculated. Pump flow rate was maintained at 2.4 L/min/ m2 during CPB as per standard unit protocol. Arterial and mixed venous blood samples were taken during the cooling, stable hypothermia and rewarming phases of CPB. Nasopharyngeal temperatures and flow rates were recorded contemporaneously. The blood samples were analysed for oxygen saturation, haemoglobin concentration and partial pressures of oxygen and carbon dioxide. The values of the three time points were meaned. All potential predictor variables were then univariately correlated with mixed venous oxygen saturation (SvO2). Those correlating significantly (p < 0.1) were entered into a multivariate linear regression model. Nasopharyngeal temperature (beta = 0.615, p < 0.001) and lean body mass (beta = 0.256, p < 0.028) were the only significant predictors of SvO2 (r2 = 0.433, p2 < 0.001). Pump flow rates maintained at 2.4 L/min/m2 throughout CPB results in relative over-perfusion during hypothermia. Lean body mass may be a more sensitive estimate of systemic metabolism and, therefore, may provide a more accurate means of determining pump flow rate than body surface area in patients undergoing heart surgery.     

Use of a combined right ventricular ejection fraction-oximetry catheter system for coronary bypass surgery.

OBJECTIVE: To evaluate the reproducibility and accuracy of a new pulmonary artery catheter system that provides both right ventricular ejection fraction and continuous venous oxygen saturation monitoring. DESIGN: Criterion standard study. SETTING: University medical center. PATIENTS: A consecutive sample of ten patients undergoing elective coronary artery bypass surgery provided informed consent for the study. Exclusion criteria included emergency surgery or clinically important preoperative tricuspid regurgitation as assessed by echocardiography. None of the patient sample was excluded. MEASUREMENTS: Catheter-derived mixed venous and arterial oximetry data were compared with simultaneous values obtained using conventional laboratory cooximetry methods. Measurements were performed before cardiopulmonary bypass and intermittently up to 48 hrs after cardiopulmonary bypass. The variability of cardiac output and computed right ventricular ejection fraction was also assessed concurrently with the oximetry analysis. RESULTS: A significant correlation was observed for mixed venous oxygen saturation between catheter-derived and laboratory cooximetry data (r2 = .81, p < .01). Similarly, arterial oxygen saturation values obtained from pulse oximetry and laboratory values were significantly related (r2 = .81, p < .01). The coefficient of variation for each set of five repeated measurements for cardiac output was 8%, and for computed right ventricular ejection fraction, it was 16%. CONCLUSIONS: The combined catheter system provides the means to monitor both mixed venous oxygen saturation and right ventricular ejection fraction. These data provide a reliable and detailed assessment of cardiopulmonary function that should prove beneficial in the critical care setting.     

体外循环冠状动脉旁路移植术后低氧血症的危险因素分析

目的 通过分析体外循环冠状动脉旁路移植术后低氧血症的危险因素,探讨体外循环冠状动脉旁路移植术后低氧血症的发生规律及特点.方法 我院2007年5月至2009年5月行体外循环冠状动脉旁路移植术483例,对86例术后发生低氧血症患者的相关因素进行单因素和多因素分析.结果 单因素分析显示:低氧血症组与非低氧血症组高龄(≥65岁)、长期吸烟、糖尿病、慢性阻塞性肺气肿、术前左心室射血分数＜45%、过度肥胖、血制品输入≥1000 ml等比例差异均有统计学意义(x2值分别为12.632、15.517、6.833、16.723、9.383、9.668、18.427,P均＜0.05);多因素分析显示:术前肺功能异常、体外循环时间过长(≥2 h)、血制品输入≥1000 ml、低蛋白血症以及肺部感染是术后低氧血症发生的独立危险因素(OR分别为9.912、15.658、9.716、7.673、3.835,95% CI分别为1.217～87.522、1.946～109.256、1.338～36.837、1.925～105.516、1.219～6.593).结论 体外循环冠状动脉旁路移植术后低氧血症是围术期多种因素共同作用的结果,提高对围术期低氧血症危险因素的认识,正确指导临床预防与治疗,可以避免术后低氧血症的发生.

Abstract：

Objective To analyze the risk factors of hypoxemia after coronary artery bypasses grafting (CABG) along with cardiopulmonary bypasses and to understand the regular pattern and characteristics of hypoxemia after CABG. Methods The risk factors of hypoxemia were studied by one way analysis and multivariate logistic regression analysis in 86 patients with hypoxemia after CABG along with cardiopulmonary bypass. Results One way analysis indicated that hypoxemia after CABG along with cardiopulmonary bypass was related to senility ( ≥ 65 years ), smoking history, diabetes mellitus, chronic obstructive pulmonary disease ( COPD), left ventricular ejection fraction ( LVEF ＜ 45 % ), obesity before operation, transfusion ( ≥ 1000 ml );multivariate analysis indicated that pulmonary dysfunction before operation, longer extracorporeal circulation time ( ≥2 h), hypoalbuminemia and pulmonary infection were independent risk factors of hypoxemia after CABG along with cardiopulmonary bypass. Conclusion Multiple risk factors contributed to hypoxemia after CABG along with cardiopulmonary bypass. Increase the awareness of risk factors of perioperative hypoxemia may guide the prevention and treatment, even alleviate or avoid the hypoxemia postoperatively.     

Effects of ventilation and nonventilation on pulmonary venous blood gases and markers of lung hypoxia in humans undergoing total cardiopulmonary bypass

OBJECTIVE: To assess the effects of lung oxygenation and ventilation vs. lung collapse on pulmonary markers of lung hypoxia. DESIGN: A prospective, nonrandomized, nonblinded comparative study. SETTING: University department of anesthesiology and cardiothoracic surgery. SUBJECTS: Twelve adult patients undergoing coronary bypass grafting requiring total cardiopulmonary bypass. INTERVENTIONS: Single lung ventilation during total cardiopulmonary bypass (tidal volume, 150 mL; respiratory rate, 6 breaths/min; inspiratory oxygen fraction, 0.5) while the contralateral lung was allowed to collapse completely without oxygenation. MEASUREMENTS AND MAIN RESULTS: At the beginning and at the end of total cardiopulmonary bypass (duration, 59-65 mins), blood was aspirated from the right and left pulmonary veins and the radial artery for measurement of blood gases and concentrations of endothelin-1, big-endothelin, thromboxane B2, lactate, and lactate dehydrogenase. Nonventilation during total cardiopulmonary bypass compared with ventilation resulted in lower pulmonary venous P(O2) values (57+/-15 torr [7.6+/-2.0 kPa] vs. 103+/-23 torr [13.7+/-3.1 kPa]) and higher thromboxane B2 concentrations (488+/-95 pg/mL vs. 434+/-92 pg/mL). The concentrations of endothelin-1, big-endothelin, lactate, and lactate dehydrogenase in the pulmonary veins did not differ significantly between nonventilated and ventilated lungs. CONCLUSIONS: Development of pulmonary tissue hypoxia during 1 hr of nonventilation and cardiopulmonary bypass with completely inhibited pulmonary arterial blood flow is unlikely, suggesting that enough oxygen is stored in or is provided to the collapsed lung. Thus, nonventilation during total cardiopulmonary bypass does not appear to contribute to postoperative respiratory dysfunction by causing pulmonary tissue hypoxia. These results, however, do not exclude that mechanical factors of ventilation might benefit the lung during cardiopulmonary bypass.