原位肝移植围术期混合静脉血氧饱和度改变及临床意义

目的 观察原位肝移植围术期混合静脉血氧饱和度（SvO2）的变化及其临床意义。方法 20例终末期肝硬化患者接受原位肝移植术。采用心排仪持续监测围术期SvO2、氧供（DO2）、氧耗（VO2）、氧摄取率（ER02）、体温、心排血量（CO）、平均动脉压（MAP）的变化，分析肝移植围术期SvO2与上述各指标的相关性。结果 SvO2在无肝期前15min较术前增高（P〈O．05），在无肝期30min较无肝期前15min显著降低（P〈0．05），在新肝期30min和术毕较术前均显著增高（P均〈O．05）。机体DO2、VO2在无肝期30min均显著降低（P均〈O、05），而在进入新肝期后均显著增高（P均〈O、05）；ERO2进入新肝期后显著增加（P〈O.05）。SvO2在各时间点均与VO2有显著相关性（P均〈O．05），而与DO2、血红蛋白无相关性（P均〉0．05）；SvO2术前与CO有显著相关性（P〈O．05），其他时间点均无相关性（P均〉O．05）。结论 原位肝移植围术期持续监测SvO2对于改善氧代谢具有重要的临床意义。     

麻醉对猪失血性休克模型血流动力学及氧动力学的影响

目的 探讨麻醉对猪失血性休克血流动力学及氧动力学的影响.方法 巴马香猪16头随机分为:麻醉休克组和清醒休克组,每组8头.按30 mL/kg放血建立失血性休克模型,记录建模前及建模后4 h内不同时点的核心体温、心率(HR)、平均动脉压(MAP)、肺动脉压(PAP)、肺动脉楔压(PAWP)、中心静脉压(CVP)、心输出量(CO)、血红蛋白(Hb)、混合静脉血氧饱和度(SvO2)及血气分析变化,并计算氧摄取率(O2ER)、氧供指数(DO2I)和氧耗指数(VO2I).结果 模型建立后清醒组动物核心体温略有下降,但麻醉组动物核心体温下降更加明显.两组的HR、MAP、PaO2、PaCO2及pH值未表现出明显差异,但清醒组乳酸水平明显高于麻醉组.尽管模型建立后两组的DO2I和VO2I都出现了相同幅度的下降,但清醒组的DO2I、VO2I和O2ER在模型建立前后都显著高于麻醉组.结论 麻醉可以减轻失血性休克后的氧代谢紊乱,麻醉引起的诱导性低温可能是造成这种现象的原因.     

自体输血对冠心病行冠脉搭桥手术病人血液学、血液动力学及氧合状况的影响

目的 观察自体输血对冠脉搭桥手术病人血液学、血液动力学及氧合状况的影响。方法 50例冠脉搭桥手术病人心功能Ⅱ一Ⅸ级年龄50—72岁，观测自体输血前后血液学，血液动力学及氧合的变化。结果 心脏复跳后RBC、HB、HCT、PLT明显降低，凝血酶原时间（PT）和活化部分凝血酶原时间（APTT）明显延长，PvO2，SvO2值明显降低，氧摄取率（O2ER）增高。术毕回输自体血后，HB和HCT明显回升，虽仍低于术前水平，但MAP、CVP、PCWP和CI维持稳定，混合静脉血氧分压（PvO2）和混合静脉血氧饱和度（SvO2）明显回升并在正常范围，QER明显回降。结论 中度血液稀释和回收式自体输血，术中应用于冠脉搭桥手术病人，对组织氧合状况及凝血功能影响不明显。     

危重病患者循环内皮细胞数量和氧代谢指标的动态变化

目的探讨危重病患者循环内皮细胞（CEC）数量、氧代谢指标的动态变化。方法35例危重病患者，20例健康体检者作为对照。用等密度梯度离心法分离血CEC，危重病患者右颈内静脉Swan Ganz导管血流动力学监测，于病后3、6、9和12d又各采集静脉血2mL，并记录其氧分压、血氧饱和度（SaO2）、血红蛋白（Hb）、CEC等指标，计算氧供（DO2）、氧耗（VO2）。结果危重病组与正常对照组比较，CEC数量明显增加，差异有显著性（P〈0.05）。危重病组患者3d内VO2随DO2增加的幅度增大，表明DO2和VO2呈病理性依赖关系；但3d后随着DO2增加，VO2的增加速度明显趋于平缓，VO2与DO2之间呈非依赖性关系。结论危重病患者血管内皮细胞功能受损，氧耗增加。     

抑制一氧化氮合成对犬感染性休克的影响

目的：探讨一氧化氮（NO）在感染性休克中的作用机制，及抑制NO合成的治疗学意义。方法：10只健康杂种狗予戊巴比妥麻醉，大肠杆菌内毒素（LPS）60μg·kg-1·h-1×30min静脉滴注，继以生理盐水（NS）15ml·kg-1·h-1维持。随机分成两组。组Ⅰ、组Ⅱ在LPS开始注射后60min分别单剂注射NS30ml、NS30ml＋L-硝基精氨酸（LNNA）20mg·kg-1。观察血液动力学、氧动力学、尿NO3/NO2（NOx）、血浆内皮素（ET）变化。结果：LPS注射后60min两组动物均呈典型高动力状态，平均动脉压（MAP）、体循环阻力（SVRI）明显下降，心脏指数（CI）轻度增加。LPS使氧输送（DO2）、氧耗（VO2）增加。尿NOx升高。LNNA使MAP恢复至基础水平，SVRI、PVRI显著升高且超过基础值；CI下降，DO2、VO2减少，PvO2上升，尿NOx低于组Ⅰ，而ET明显高于组Ⅰ。结论：LPS诱导的犬感染性休克的血液动力学异常与NO过多释放有关，NO抑制LPS引起的ET释放。LNNA虽可逆转低血压，但对感染性休克的整体治疗不利。     

体外循环中空气法胃粘膜pH值与氧供 氧耗的变化

目的观察体外循环（CPB）中空气法胃粘膜pH值与氧供、氧耗的变化了解体外循环期间胃粘膜的血流灌注。方法选择择期行体外循环心脏手术30例，麻醉后置入TONO胃管通过空气法胃粘膜张力模块自动持续监测胃粘膜二氧化碳分压（PgCO2），在监护仪中输入麻醉诱导后30min、体外循环30min、60min、停体外循环后30min和60min时间点的动脉和混合静脉血气分析结果，计算获得各时点的胃粘膜pH值（pHi）、氧供（DO2）和氧耗（VO2）等数据。结果PgCO2在CPB期间明显低于术前（P〈0．01），停CPB后恢复到术前水平；pHi的变化体外环循期间显著升高（P〈0．01），停CPB后恢复术前水平；DO2和VO2变化：CPB期间明显低于术前（P〈0．01），停CPB后明显高于CPB期间（P〈0．01），停CPB 60min后明显高于术前（P〈0．01）。结论本研究中的病例在低温体外循环期间未存在胃肠粘膜血流灌注不足。     

颅脑外伤患者围手术期氧代谢特点及临床意义

目的:探讨颅脑外伤患者围手术期的氧动力学变化特点以及与临床转归的关系.方法:对2004年6月至2006年6月我科收治的8例颅脑外伤患者在围手术期进行Swan-Ganz漂浮导管监测,并根据同时间点的动脉、混合静脉血氧分压、氧饱和度、血红蛋白等指标,计算出氧供(DO2)、氧耗(VO2)和氧摄取率.结果:非多器官功能衰竭(MODS)患者随着DO2的上升VO2上升缓慢,出现"平台效应",MODS存活组和MODS死亡组VO2随着DO2的上升而继续上升,出现病理性氧依赖.结论:颅脑外伤MODS患者氧摄取已出现明显障碍,导致VO2对DO2的病理依赖,治疗中应尽可能提高DO2水平,可能会减轻颅脑外伤患者MODS的发生和发展.     

重型肝炎肝移植围术期血流动力学变化及监测意义

目的 探讨重型肝炎患者肝移植围术期血流动力学的变化。方法 10例重型肝炎患者行原位肝移植术。麻醉诱导后经右颈内静脉放入肺动脉导管，左桡动脉放置动脉导管，通过换能器连接HP多功能监测仪及Edwards持续心排监测仪，持续监测心排血量(CO)、平均动脉压(MAP)等血流动力学参数，记录体循环阻力(SVR)、肺循环阻力(PVR)、心脏指数(CI)、每搏指数(SI)等相关指标。结果 ①术中心率(HR)增快，MAP在无肝早期和新肝早期均降低；中心静脉压(CVP)变化显著，在无肝期明显下降，新肝早期急剧增高，新肝60min后逐渐下降；平均肺动脉压(MPAP)的变化与平均肺动脉楔压(PAWP)的变化一致，均在无肝期显著下降，新肝早期急剧增高。②SVR在手术开始前处于较低水平，无肝期开始后进行性升高，新肝期开始时较无肝期明显下降；PVR在新肝期变化最明显，早期显著升高后逐渐降至术前水平。③左室作功指数(LVSWI)在无肝期显著下降，新肝期1min继续下降后逐渐升高；右室作功指数(RVSWI)在无肝期显著下降，新肝期逐渐升高。④CO及C1始终处于高水平，无肝期较无肝前期明显下降，新肝期逐渐升高至较术前更高水平。结论 重型肝炎患者原位肝移植围术期血流动力学的变化以无肝期和新肝期最显著，但CO一直处于高输出状态。SVR变化复杂，受血压、血容量、血管活性药物等多种因素影响。围术期监测血流动力学可指导加强麻醉管理，对预防和控制心功能不全、低血容量具有重要意义。     

异氟烷麻醉对失血性休克血液循环和氧代谢的影响

目的 研究异氟烷麻醉对失血性休克(HS)血液循环和氧代谢的影响.方法 巴马小型猪16只,随机分为两组(n=8):清醒对照组(C组)和麻醉实验组(A组).两组猪分别于清醒和异氟烷麻醉两种状态下在15 min内按全身血容量的40%(即按30 mL/kg计算)匀速放血制备休克模型,监测放血前和放血后4 h内不同时间点的肺动脉温度(TP)、心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)、平均肺动脉压(MPAP)、肺动脉楔压(PAWP)、心输出量(CO)、混合静脉血氧饱和度(SmvO2)及血气指标;计算每搏输出量(SV)、体循环阻力(SVR)、氧摄取量(Ca-vO2)、氧供(DO2)、氧耗(VO2)和氧摄取率(O2ER);记录每头猪的生存时间.结果 HS发生后,C组和A组HR分别增快至(193±19)次/min和(126±16)次/min,其后C组逐渐下降,A组变化较小;C组MAP和CO下降后回升较快、幅度较大,于HS 90 min分别回升至80 mm Hg和1.5 L/min以上,而A组回升不明显;但两组SVR增加较一致,且A组MPAP降低后回升较明显.HS导致两组DO2和VO2均分别降低至200 mL/min和150 mL/min以下,但A组下降并维持在更低水平,其O2ER、Ca-vO2和乳酸(LA)依然较低,SmvO2较高;两组猪在4 h内均存活.结论 异氟烷麻醉下,HS机体血流动力学应激代偿反应明显减弱,心血管系统受抑明显,氧供减少,但氧耗降低更显著,氧动力学失衡明显减轻.     

生脉注射液对脓毒性休克绵羊血流动力学及氧代谢的影响

目的探讨生脉注射液对脓毒性休克绵羊血流动力学及氧代谢的影响。方法用静脉注射内毒素脂多糖（LPS）的方法诱导绵羊脓毒性休克模型。以生脉注射液1ml／kg缓慢静脉注射，观察治疗前以及治疗后即刻、30、60和120min时绵羊血流动力学和氧代谢的变化。结果18只脓毒性休克绵羊给予生脉注射液后即刻出现平均动脉压（MAP）、平均肺动脉压（MPAP）、心排血指数（CI）、左室作功指数（LVSWI）、右室作功指数（RVSWI）均显著升高（P均〈0．05），并在其后的120min内保持稳定；中心静脉压（CVP）、肺动脉嵌顿压（PAWP）、体循环阻力指数（SVRI）、肺循环阻力指数（PVRI）在注射生脉注射液前后无明显改变（P均〉0．05）。给药后即刻组织氧供给（DO2）就较给药前显著增加（P均〈0．05），自给药后30min组织氧消耗（VO2）显著增加（P均〈0．05）；氧摄取率（O2ER）和血中乳酸（Lac）水平无明显改变（P均〉0．05）。结论生脉注射液可以通过改善心功能而显著改善脓毒性休克绵羊的血流动力学效应，同时通过提高DO2和组织利用氧的能力而改善组织氧代谢。     

Correlating the severity of paraquat poisoning with specific hemodynamic and oxygen metabolism variables

OBJECTIVE: To investigate the hemodynamics and oxygen metabolism of patients with varying degrees of severity of paraquat poisoning. DESIGN: Prospective, observational, clinical study. SETTING: Intensive care unit in a university hospital. PATIENTS: Forty-three consecutive patients with paraquat and/or diquat poisoning were classified into three groups by the severity index of paraquat poisoning (SIPP; hr/mg/L). INTERVENTIONS: Standard treatments included specific respiratory management, fluid resuscitation, and aggressive circulatory support. MEASUREMENTS AND MAIN RESULTS: Serum paraquat and diquat levels were measured at arrival, and SIPP was calculated. The cardiac index (CI), left ventricular stroke work index (LVSWI), systemic vascular resistance index (SVRI), oxygen delivery index (DO2I), oxygen consumption index (VO2I), and oxygen extraction ratio (O2ER) were measured at 6, 12, 24, 36, 48, 72, and 96 hrs postadmission. A significant inverse correlation between SIPP and survival time was found in 31 fatal cases (r = .85; p < .001). In the SIPP 10-50 group, CI, DO2I, VO2I, and O2ER were maintained at higher levels than in the SIPP group of <10 (p < .05), whereas SVRI decreased significantly (p < .05). In the SIPP group of >50, CI, LVSWI, SVRI, DO2I, and VO2I decreased, whereas O2ER had a tendency to increase progressively. There was a significant correlation between SVRI and SIPP, O2ER and SIPP, and O2ER and SVRI 24 hrs after admission, respectively (p < .001). CONCLUSIONS: Paraquat poisoning is characterized by high oxygen consumption with high oxygen extraction, with the degree of derangement based on the severity index. The development of a marked imbalance between increased oxygen demand and decreased oxygen supply because of myocardial depression might be a possible cause of death in circulatory failure.     

环境低温对非麻醉猪失血性休克血流动力学及氧代谢的影响

目的 探讨环境低温对非麻醉猪失血性休克血流动力学及氧代谢的影响.方法 沈阳军区总医院动物中心提供的巴马香猪16头随机(随机数字法)分为:室温休克组和低温休克组,每组8头.按30 mL/kg放血建立失血性休克模型,记录建模前及建模后4h内不同时点的核心体温、心率、平均动脉压、中心静脉压、心输出量、混合静脉血氧饱和度及血气等变化,并计算氧摄取率、氧供指数和氧耗指数.采用SPSS11.0软件包行计量资料的成组t检验.结果 模型建立后室温组动物的核心体温略有下降,环境低温使核心体温下降更加明显.低温组动物的病死率较室温组明显增加(P＜0.05).休克导致氧供和氧耗明显下降.室温组和低温组的血流动力学指标、氧供和氧耗的差异无统计学意义,但两者在pH值、乳酸和氧提取率上差异具有统计学意义(P＜0.05).结论 环境低温加重了失血性休克后的氧代谢紊乱,使预后进一步恶化.     

原位肝移植非静-静脉转流围术期肺氧合及肺内分流的变化

目的观察非体外静静脉转流术下原位肝移植(OLT)围术期肺氧合功能及肺内分流的改变。方法对19例晚期肝病行OLT手术的患者采用静吸复合麻醉,无肝期均未使用体外静静脉转流术。常规经右颈内静脉放置SwanGanz导管持续监测心排血量(CO),测定肺氧合功能及肺内分流率。分别在麻醉诱导后、无肝前30min、无肝30min、新肝30min和术毕抽取桡动脉血和肺动脉血进行血气分析,记录不同时期的动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)和心排血指数(CI),计算肺泡动脉氧分压差(PAaO2)。根据肺内分流标准模型公式计算肺内分流率(Qs/Qt)。结果麻醉诱导后吸入氧浓度(FiO2)1.00情况下,PaO2为(385.0±56.4)mmHg(1mmHg=0.133kPa),PAaO2和Qs/Qt均明显高于正常参考值。麻醉诱导后各项指标与无肝前30min相比差异均无显著性;无肝30minCO和CI明显下降(P均<0.01),Qs/Qt明显下降(P<0.05);新肝30minPaO2、PaCO2均明显升高(P均<0.05),PAaO2明显下降(P<0.05),CO和CI均明显升高(P均<0.01);术毕CO和CI也均明显升高(P均<0.05),并维持在较高的水平,Qs/Qt明显下降(P<0.05),但PaO2、PaCO2、PAaO2则均无明显变化。结论OLT患者非静静脉转流术前和术中均存在明显的肺氧合功能障碍。     

高容量血液滤过对脓毒症合并急性呼吸窘迫综合征血流动力学和氧代谢的影响

目的探讨连续性高容量血液滤过(HVHF)对严重脓毒症合并急性呼吸窘迫综合征(ARDS)的呼吸、血流动力学和氧代谢的影响。方法选择由各种病因导致的12例脓毒症并发ARDS患者,全部病例均在呼吸机支持下每日连续给予床边HVHF(置换液流量80ml·kg-1·h-1)治疗12~18h,观察治疗前后患者炎性介质〔肿瘤坏死因子α(TNFα)、白细胞介素6(IL6)、IL8、IL10〕、氧合指数(PaO2/FiO2)、急性生理学与慢性健康状况评分系统(APACHE)评分、多器官功能障碍综合征(MODS)评分和胸腔液体容量(TFC)的变化。通过Swan Ganz导管获得心排血量(CO)、外周循环阻力(SVR)、肺循环阻力(PVR)、平均肺动脉压(MPAP)、肺动脉楔压(PAWP)、动脉血氧含量(CaO2)、混合静脉血氧含量(CvO2)、氧消耗(VO2)、氧输送(DO2)和氧摄取率(O2ER)。结果HVHF48h后的MPAP、PVR和TFC均明显下降(P均<0.05)。HVHF72h后,TNFα、IL6和IL8含量较HVHF前均明显下降(P均<0.05),DO2、O2ER和VO2逐渐稳定,并伴随动脉氧分压(PaO2)、PaO2/FiO2和气道峰压(Ppeak)的改善(P<0.05或P<0.01)。结论连续性HVHF可通过清除部分细胞因子,减少TFC,改善严重脓毒症合并ARDS患者的呼吸、血流动力学和氧代谢。     

Effects of positive end-expiratory pressure on tissue gas tensions and oxygen transport

To determine whether positive end-expiratory pressure (PEEP) impairs peripheral tissue oxygenation, hemodynamic variables including blood and subcutaneous tissue gas tensions were measured at 0, 5, 10, 15, and 20 cm H2O of PEEP, in 9 patients who were being mechanically ventilated for acute pulmonary failure. Increasing the level of PEEP produced parallel decreases in cardiac output and oxygen delivery (DO2 = cardiac output X arterial oxygen content); however, there were no significant changes in mean arterial blood pressure (MAP), oxygen consumption (VO2), mixed-venous oxygen tension (PvO2), pH, or base excess. Subcutaneous tissue oxygen (PtO2) and carbon dioxide (PtCO2) tensions, which were directly measured in the femoral region by a mass spectrometer, also remained at their baseline levels (zero end-expiratory pressure). We concluded that peripheral tissue oxygenation is not impaired up to the level of 20 cm H2O of PEEP, even though DO2 significantly decreases.     

Oxygen delivery-dependent oxygen consumption in acute respiratory failure

OBJECTIVE: To investigate whether oxygen consumption (VO2) is dependent on oxygen delivery (DO2) in adult respiratory distress syndrome (ARDS) and non-ARDS acute respiratory failure. DESIGN: Intervention study of a consecutive sample of patients admitted to the ICU with the diagnosis of acute respiratory failure. SETTING: Tertiary care center. PATIENTS: Thirteen consecutive patients with a diagnosis of ARDS and 11 with a diagnosis of respiratory failure not due to ARDS. Patients were monitored with an oximetric pulmonary artery catheter and mechanically ventilated. INTERVENTIONS: DO2 was decreased by the application of positive end-expiratory pressure (PEEP) (20 cm H2O), and subsequently increased by an iv infusion of dobutamine (10 micrograms/kg.min). RESULTS: After the application of PEEP, DO2 decreased significantly in both groups. However, VO2 decreased significantly (p less than .01) only in the ARDS group. When dobutamine was infused, DO2 increased significantly (p less than .01) in both groups, but VO2 increased only in ARDS patients. DO2 correlated significantly with VO2 both in ARDS (r2 = .81, p less than .01) and in non-ARDS (r2 = .38, p less than .05) patients. The correlation coefficient was significantly higher for ARDS than for non-ARDS patients. Comparing the slopes of the regression lines, a stronger dependency of VO2 on DO2 was found in ARDS than in non-ARDS respiratory failure (p less than .001). The oxygen extraction ratio correlated with DO2 in non-ARDS patients (r2 = .49, p less than .05), but not in ARDS patients. CONCLUSIONS: VO2 is dependent on DO2 over a wide range of DO2 values in acute respiratory failure. This dependency phenomenon is much stronger in ARDS than in respiratory failure due to other causes. Due to the abnormal dependency of VO2 on DO2, changes in the oxygenation status may not be reflected by changes in mixed venous oxygen saturation in ARDS.     

Early physiologic changes in canine fecal peritonitis

Oxygen delivery (DO2) and related variables were studied in eight dogs during severe untreated peritonitis induced by cecal ligation and perforation. The development of peritonitis was accompanied by abdominal fluid sequestration and significant increases in hemoglobin (Hgb), arterial oxygen content (CaO2), and P50. Changes in mixed venous PO2 (P-vO2), mixed venous saturation (S-vO2), DO2, oxygen uptake (VO2), cardiac index (CI), and arteriovenous O2 difference (C[a--v]O2) were not significant. When blood volume was returned to normal levels with dextran, CI rose and C(a--v)O2 decreased; P-vO2 increased and Hgb returned to baseline levels. In this animal model, sepsis and fluid sequestration produced an increase in blood O2 capacity and CaO2, which sustained DO2 and VO2. No changes were observed in P-vO2 or S-vO2. The hyperdynamic state of severe sepsis became evident only after reversing hemoconcentration by colloid infusion. The increase in P-vO2 and S-vO2 after volume loading is possibly related to primary septic mechanisms and/or to changes in DO2.     

'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates

Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO(2)), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO(2)), oxygen consumption (VO(2)), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO(2)), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO(2)) were calculated. All demographic parameters except for Hbflow and DO(2) correlated with NIRS parameters. Heart rate correlated with TOI, SvO(2), VO(2) and VR. SaO(2) correlated with FOE/FTOE. MAP correlated with Hbflow, DO(2), VO(2) and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO(2). Hb-blood correlated with FOE and VR. pCO(2) levels correlated with TOI and SvO(2). The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data.     

Oxygen consumption is increased in the postanesthesia period after burn excision

We studied the intraoperative and postoperative effects of anesthesia and wound excision on oxygen delivery and oxygen consumption after burn injury. Twenty adult sheep were studied: six had halothane anesthesia alone and 14 had anesthesia and third-degree burns over 15% of the total body surface. Body temperatures were maintained within 1 degree C of baseline value during the operations. The burns on six sheep were totally excised and hide from donor sheep was grafted 3 hours after injury; in eight sheep, excision and grafting were done 5 days after injury. We found that 3 hours of anesthesia in controls decreased oxygen delivery (DO2) by 22% +/- 6% and oxygen consumption (VO2) by 30% +/- 7% from waking baseline values primarily because of a decrease in cardiac output as oxygen (O2) extraction from hemoglobin also decreased. However, no base deficit developed. DO2 and (VO2) transiently increased to 9% +/- 3% above baseline value on the sheeps' return to the waking state. Anesthesia and wound excision, which began 3 hours after the burns were formed, decreased DO2 and VO2 by 25% +/- 4% and 32% +/- 4%, respectively, despite baseline filling pressures. However, a base deficit of -3 +/- 1 mEq/L developed during the two-hour operations, which began with the administration of anesthesia alone. Oxygen consumption increased to 25% +/- 6% above the waking baseline value upon each subject's return to the waking state. In the sheep treated 5 days after burn injury, DO2 decreased by 35% +/- 6% and VO2 decreased by 42% +/- 6% below the value during the waking hypermetabolic state when the sheep were under anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)