Effects of thoracic epidural anaesthesia on pulmonary venous admixture and oxygenation during one-lung ventilation

BACKGROUND: In this clinical randomized study, the effects of four anaesthesia techniques during one-lung ventilation [total intravenous anesthesia (TIVA) with or without thoracic epidural anaesthesia (TEA) (G-TIVA-TEA and G-TIVA), isoflurane anaesthesia with or without TEA (G-ISO-TEA and G-ISO)] on pulmonary venous admixture (Qs/Qt) and oxygenation (OLV) were investigated. METHODS: In 100 patients (four groups, 25 patients in each) undergoing thoracotomy, a thoracic epidural catheter was inserted pre-operatively. In G-TIVA-TEA and G-ISO-TEA, bupivacaine 0.1% + 0.1 mg/ml morphine was administered intra-operatively (10 ml of first bolus + 7 ml/h infusion). Propofol infusion or isoflurane concentration was adjusted to keep a bispectral index (BIS) of between 40 and 50 in all groups. FiO(2) was 0.8 during OLV and 0.5 before and after OLV. Partial arterial and central venous oxygen pressures (PaO(2) and PvO(2)), arterial and venous oxygen saturations and Qs/Qt values were recorded before, during and after OLV. RESULTS: During OLV, PaO(2) was significantly higher and Qs/QT significantly lower in G-TIVA-TEA and G-TIVA compared with G-ISO-TEA and G-ISO (PaO2: 188 +/- 36; 201 +/- 39; 159 +/- 33; 173 +/- 42 mmHg, respectively; Qs/Qt: 31.2 +/- 7.4; 28.2 +/- 7; 36.7 +/- 7.1; 33.7 +/- 7.7%, respectively). No statistical changes were observed in patients with TEA compared with without TEA in any measurement. CONCLUSION: During OLV, TEA does not significantly affect the oxygenation and Qs/Qt and can be used safely regardless of whether TIVA or inhalation techniques are used.     

硬膜外阻滞复合全麻对单肺通气期间气体交换的影响

目的 观察胸段硬膜外阻滞复合全麻对单肺通气期间气体交换的影响.方法 随机选择ASA Ⅰ～Ⅱ级择期开胸手术病人80例,将病人随机分为两组,全麻复合硬膜外麻醉组(A组)和全麻组(B组),每组40例.两组病人在开胸前双肺通气20 min(T1)时及开胸后单肺通气(OLV)30 min(T2)、60 min(T3)、120 min(T4)时,分别采动脉血及混合静脉血,观察病人动静脉血气情况并计算肺内分流率(Qs/Qt)值、肺泡-动脉血氧分压差(A-aDO2)和无效腔量/潮气量(Vd/Vt)值.结果 与T1相比,两组T2-4时Paw均升高(P<0.01),T2-4时Qs/Qt均增加(P<0.01),A-aDO2增加(P<0.01),PaO2降低(P<0.01),而Vd/Vt,血压、心率变化无统计学差异(P>0.05);与B组相比,A组T2-4时的Qs/Qt增加(P<0.01),A-aDO2增加(P<0.01),PaO2,降低(P<0.01),而Vd/Vt,血压、心率变化无统计学差异(P>0.05).结论 单肺通气期间硬膜外阻滞复合全麻对肺换气功能有影响,使Qs/Qt增加,PaO2下降,A-aDO2增大;对肺泡通气功能指标Vd/Vt影响甚微.     

Controlled hypercapnia during one-lung ventilation in patients undergoing pulmonary resection

BACKGROUND: In a pilot study, the haemodynamic and gas exchange effects of acute hypercapoia during one-lung ventilation in thoracotomy patients were investigated. The effects of normocapnic one-lung ventilation (OLV-N) on haemodynamics and pulmonary gas exchange were compared with those of hypercapnic one-lung ventilation (OLV-H) in 14 patients undergoing pulmonary lobectomy. METHODS: Hypercapnia was induced by decreasing tidal volume until PaCO2 increased to 8-9 kPa. During OLV, minute ventilation was reduced from 8.8+/-1.7 to 4.2+/-0.7 l min(-1). RESULTS: Cardiac index (from 3.3+/-0.6 to 3.9+/-0.6 l min(-1), P<0.01) and pulmonary vascular resistance index (from 245+/-96 to 347+/-125 dyn s cm(-5) m(-2), P<0.05) increased during OLV-H, whereas systemic vascular resistance index decreased from 1952+/-403 to 1636+/-361 dyn s cm(-5) m(-2) (P<0.01). Pulmonary oxygenation remained unchanged. CONCLUSIONS: All patients had an uneventful course during OLV-H. The determinants of pulmonary oxygenation during hypercapnic one-lung ventilation remain to be further elucidated.     

A comparison of the effects of desflurane and isoflurane on arterial oxygenation during one-lung ventilation

In a randomised prospective cross-over study, we compared the effects of desflurane and isoflurane on arterial oxygenation, heart rate and mean arterial pressure during one-lung anaesthesia. Thirty patients scheduled for oesophagogastrectomy were randomly assigned to one of two groups. One group of 15 patients received desflurane to an end-tidal concentration of 6% in oxygen from induction until the end of 30 min of open chest one-lung ventilation in the lateral position. This was followed by isoflurane to an end-tidal concentration of 1.1% in oxygen for the next 30 min of one-lung ventilation. The other group of 15 patients received the two anaesthetic agents in the reverse order. We found no significant difference in arterial oxygenation, heart rate or mean arterial pressure between the two inhalational agents. In the subgroup of 10 patients with pulmonary artery catheters, we found no significant differences in mixed venous saturation, derived shunt or cardiac output. We conclude that during one-lung ventilation, the choice between desflurane and isoflurane does not significantly influence arterial oxygenation.     

秣醉药物对单肺通气时缺氧性肺血管收缩影响的研究进展

缺氧性肺血管收缩（hypoxicpuImonaryvasoconstriction，HPV）是肺血管发生快速、可逆的收缩反应，它可使低氧肺泡的血流减少而使氧合更充分的血液转移到通气较好的肺，减少无效通气和功能性分流，减少低氧血症的发生。本文将对单肺通气时影响缺氧性肺血管收缩的代表性麻醉药物以及相关研究进展进行综述。     

Gradient of bronchial end-tidal CO2 during two-lung ventilation in lateral decubitus position is predictive of oxygenation disorder during subsequent one-lung ventilation

Purpose  Hypoxemia is one of the major problems during one-lung ventilation (OLV). During two-lung ventilation (TLV) using a double-lumen bronchial tube, bronchial endtidal carbon dioxide partial pressure () can be determined on both sides, independently. The is mainly dependent on the pulmonary perfusion to each lung. If the degree of oxygenation disorder during OLV were to be predictable before starting OLV, this could provide time to prepare for any subsequent hypoxemia. The aim of this study was to investigate whether the difference of (D-) between the dependent and the nondependent lungs during TLV in the lateral decubitus position (LP) could be a predictive factor for the severity of oxygenation disorder under subsequent OLV. Methods  Eighteen patients undergoing lung surgery were enrolled in this study. Anesthesia was induced with intravenous thiopental and fentanyl, supplemented by the inhalation of sevoflurane. A left-sided double-lumen bronchial tube was placed. The was independently determined on each side during TLV in the supine position (SP) and at 10 min after changing the position from SP to LP. / inspiratory fraction of oxygen () was taken at 15 min after switching from TLV to OLV in LP. Results  The decrease of / at 15 min during OLV in LP correlated with the reduction of the D- predetermined during TLV in LP (r = 0.698; P < 0.01). Conclusion  The D- predetermined during TLV in LP could be a predictive factor for the severity of oxygenation disorder after starting OLV in LP.     

Effects of propofol vs sevoflurane on arterial oxygenation during one-lung ventilation

Background: The inhibitory effect of anaesthetic agents on hypoxic pulmonaryvasoconstriction may depend upon their dose, especially whenusing a volatile agent. The aim of this randomized open studywas to compare the effects of sevoflurane and propofol, as primaryanaesthetic agents, on oxygenation during one-lung ventilation(OLV), with their administration being adjusted to maintainbispectral index (BIS) values between 40 and 60. Methods: Eighty patients scheduled for a lobectomy, receiving an epiduralmixture of ropivacaine and sufentanil, were randomly assignedto Group S (maintenance with sevoflurane) or Group P (maintenancewith propofol). After placement of a double-lumen tube, thelungs were ventilated at an inspiratory fraction of oxygen of1.0, a tidal volume of 6 ml kg^–1, and 12 bpm. Arterialblood gas samples were taken as follows: during two-lung ventilationbefore OLV, and during the first 40 min of OLV. Results: Fifteen patients were excluded (incorrect placement of the tubeor BIS outside the desired range). The two groups were comparablein terms of demographic variables, haemodynamic, and BIS levelsduring the operation. Four patients in each group had a Sp_O2<90%.Mean of the lowest Pa_O2 was 16.3 (7.5) kPa in Group S and 17.7(9.3) kPa in Group P (ns). Conclusions: Sevoflurane and propofol had similar effect on Pa_O2 during OLVwhen their administration is titrated to maintain BIS between40 and 60.     

通气侧肺吸入伊洛前列素对肺动脉压和缺氧性肺血管收缩的影响

目的 探讨雾化吸入伊洛前列素对大鼠单肺通气(one-lung ventilation,OLV)期间肺动脉压和缺氧性肺血管收缩(hypoxic pulmonary vasoconstriction,HPV)的影响。方法 雄性SD大鼠30只,随机分为A、B、C三组,每组10只。原位离体肺灌注模型建立后,调整气管导管深度致左侧肺OLV,FiO_2为100%,打开连接于呼吸回路的雾化器,A组吸入生理盐水,B组吸入伊洛前列素0.05μg·kg-1·min-1,C组吸入伊洛前列素0.1μg·kg~(-1)·min~(-1),记录灌注10min(T_1)、雾化吸入10min(T_2)和OLV 1h(T_3)的平均肺动脉压(MPAP)及左心房引流液氧分压(PaO_2)。通过测量T_1、T_2和T_3时的左心房引流液PaO_2计算氧合指数(oxygenation index,OI)。实验结束分别取双侧肺组织进行电镜检查。结果 与T_1时比较,T_2、T_3时三组MPAP明显升高(P0.05);T_2、T_3时B、C组MPAP明显低于A组(P0.05),且C组MPAP明显低于B组(P0.05)。与T_1时比较,T_2、T_3时三组OI明显降低(P0.05);T_2、T_3时C组OI明显高于B组(P0.05)。相对于B、C组通气侧,A组通气侧与A、B、C组非通气侧Ⅱ型肺泡上皮细胞核膜外突内陷,部分板层小体排空。结论 在大鼠原位肺灌注模型中,单肺通气期间雾化吸入伊洛前列素能明显降低平均肺动脉压,减少肺内分流并增加氧合。     

Effects of sevoflurane and propofol on pulmonary shunt fraction during one-lung ventilation for thoracic surgery

Forty patients requiring one-lung ventilation (OLV) for thoracicsurgery were randomly assigned to receive propofol (4-6 mg kg^–1h^–1) or sevoflurane (1 MAC) for maintenance of anaesthesia.Three sets of measurements were taken: (i) after 30 min of two-lungventilation (TLV), (ii) after 30 min of one-lung ventilation(OLV-1) in the supine position and (iii) during OLV in the lateralposition (OLV-2) with the chest open and before surgical manipulationof the lung. There were no differences between groups in patientcharacteristics or preoperative condition. Increases in shuntfraction during OLV-1 were 17.4% and 17.2% (P=0.94), those duringOLV-2 were 18.3% and 16.5% (P=0.59) for the propofol and sevofluranegroup, respectively. Cardiac index and other haemodynamic andrespiratory variables were similar for the two groups. We concludethat inhibition of hypoxic pulmonary vasoconstriction by sevofluranemay only account for small increases in shunt fraction and thatmuch of the overall shunt fraction during OLV has other causes. Br J Anaesth 2001; 86: 38–43     

Improvement of arterial oxygenation by selective infusion of prostaglandin E1 to ventilated lung during one-lung ventilation

Background:One-lung anesthesia provides a better surgical field for thoracic procedures but also impairs the arterial oxygenation and venous admixture. During one-lung ventilation, pulmonary vasoconstriction is assumed to be present within both ventilated and collapsed lungs. We propose that arterial oxygenation could be optimized by offsetting the vasoconstriction within the microcirculation of ventilated lung. Method:In an anesthetized dog model, incremental doses of prostaglandin E₁ (PGE₁) were selectively infused into the main trunk of the pulmonary artery of the ventilated lung after one-lung ventilation for 60 min (PGE₁ group, n=9). Arterial oxygenation and calculated venous admixture (Qs/Qt) was also assessed in a time-course control group (Control group, n =5). During two-lung ventilation (FIO₂: 0.66), arterial PO₂ and venous admixture was 44.22 ± 3.5 kPa and 10.7±2.3%, respectively. One-lung ventilation (FIO₂: 0.66) with left lung collapsed reduced arterial PO₂ to 11.6±1.7 kPa and increased venous admixture to 40.7±5.8% (P<0.001). Venous O₂ tension also decreased from 6.3±0.7 kPa to 5.0±0.6 kPa with a slight increase in mean pulmonary artery pressure and pulmonary vascular resistance (P <0.05). Results: During selective infusion of PGE₁ at a dose of 0.04 to 0.2 μg kg^-1 min^-1, there was a dose-dependent improvement in arterial PO₂ with a parallel reduction of venous admixture during one-lung ventilation. Arterial PO₂ increased to a maximum of 23.0±4.3 kPa, and the venous admixture decreased significantly to a minimum of 27.4±4.2% by PGE₁ at a dose of 0.04-0.4 μg kg^-1 min^-1 (P<0.01). PGE₁ resulted in a small increase in cardiac output and decreases of pulmonary pressure and pulmonary vascular resistance at a relatively high dose of 0.4 μg kg^-1 min^-1 during selective infusion (P<0.05). Conclusion: These results suggest that a selective pulmonary artery infusion of PGE₁ to the ventilated lung within the dose range of 0.04-0.4 μg kg^-1 min^-1 is practical and effective to improve arterial oxygenation and reduce venous admixture during one-lung ventilation.     

单肺通气时间对左胸一切口食管癌患者术后肺部并发症的影响

目的探讨食管癌切除术中单肺通气时间对患者术后肺部并发症和呼吸功能的影响。方法食管癌切除术患者65例,所有患者术中均持续单肺通气,按单肺通气时间长短分为A组(2小时)、B组(2~3小时)和C组(3小时),分别记录术中单肺通气时间、术前(T1)、术后30分钟(T2)及术后24小时(T3)PaO_2和PaCO_2值、术后肺部并发症发生例数、并发呼吸衰竭例数及术后总住院时间,分析并比较不同单肺通气时间对3组患者血气指标、术后肺部并发症及术后住院时间的影响。结果 A组患者PaO_2值在T3时间点为(92.77±14.97)mmHg,C组为(79.97±9.91)mmHg,两组比较,差异有统计学意义P0.05);3组间PaO_2值在T1、T2时间点、PaCO_2值在T1、T2、T3时间点间比较,差异均无统计学意义(P0.05);B组术后肺炎发生率为61.3%(19/31),C组术后肺炎发生率为68.8%(11/16),均显著高于A组(22.2%,4/18,P均0.01,C组术后肺不张发生率为43.8%(7/16),A组为5.6%(1/18),两组比较,差异有统计学意义(P0.05);C组术后平均住院时间(12.88±1.67)天,A组(10.83±1.30)天,两组比较,差异有统计学意义(P0.01)。3组患者术后并发呼吸衰竭例数比较,差异无统计学意义(P0.05)。结论食管癌患者术中长时间单肺通气可增加术后肺部并发症的发生率,延长术后住院时间。     

单肺通气期间麻醉期用药对肺内分流的影响

背景 低氧血症是单肺通气(one lung ventilation,OLV)期间最常见的并发症.缺氧性肺血管收缩(hypoxic pulmonary vasoconstriction,HPV)是肺血管对局部低氧分压的反射性收缩,可以减少肺内分流(pulmonary shunt fraction,Qs/Qt)、维持动脉血氧分压(partial pressure of arterial oxygen,PaO2)、防止低氧血症的发生.目的 探讨OLV期间麻醉期用药对Qs/Qt的影响,指导临床应用.内容 综述OLV期间麻醉期用药对机体HPV、Qs/Qt和PaO2的影响.趋向 OLV期间麻醉期用药可以对HPV产生抑制或增强作用,从而影响Qs/Qt和PaO2.临床上要避免使用抑制HPV作用、增加Qs/Qt的药物,防止患者出现低氧血症.     

参附注射液对肺叶切除术患者单肺通气期间气道阻力和氧合功能的影响

目的 评价参附注射液对肺叶切除术患者单肺通气期间气道阻力和氧合功能的影响.方法 择期胸段硬膜外阻滞复合全麻下行肺叶切除术患者60例,性别不限,年龄50 ～ 80岁,体重指数20 ～ 29 kg/m2,ASA分级Ⅱ级,采用随机数字表法,将其随机分为2组(n=30):生理盐水对照组(C组)和参附注射液组(S组).麻醉诱导前,S组静脉输注参附注射液4.5 ml·kg-1 ·h-1 20 min;C组静脉输注等容量生理盐水.分别于单肺通气前、单肺通气30、60min及术毕时记录气道峰压,并采集动脉血样,测定PaO2,计算氧合指数.结果 与C组比较,S组单肺通气30、60 min时气道峰压降低,氧合指数升高(P＜0.05).结论 参附注射液可降低肺叶切除术患者单肺通气期间气道阻力,提高氧合功能,提示其具有肺保护作用.     

Effects of sevoflurane compared with those of isoflurane on arterial oxygenation and hemodynamics during one-lung ventilation

Purpose. This study was designed to compare the effects of sevoflurane and isoflurane on Pao₂ and hemodynamic variables during one-lung ventilation (OLV) in surgical patients. Methods. Twelve patients undergoing an esophageal procedure with thoracotomy for which a long period of OLV was required were studied using a randomized crossover design. Group 1 received 1.2% isoflurane from the induction of anesthesia until 30 min after starting OLV, and then received 1.7% sevoflurane during the remaining period. In group 2, the order of the anesthetics was reversed. All experimental procedures were performed in the left lateral decubitus position with the chest opened. Arterial and mixed venous blood gases and cardiac outputs were analyzed immediately before OLV, during OLV, and after resumption of two-lung ventilation (TLV). Results. OLV produced lower Pao₂ and higher venous admixture (Q _s/Q _t) values than TLV. However, there was no significant difference between sevoflurane and isoflurane in Pao₂ or Q _s/Q _t during OLV. Other hemodynamic variables except for Pvˉo₂ showed no significant differences between the anesthetics. Conclusion. The effects of sevoflurane on Pao₂ and the hemodynamic variables were similar to those of isoflurane during TLV and OLV in the lateral decubitus position. Received for publication on January 29, 1999; accepted on August 6, 1999     

急性等容血液稀释对犬单肺通气期间肺分流与氧合的影响

目的 观察犬单肺通气期间，不同程度急性等容血液稀释对肺分流和氧供、氧耗等的影响。方法 12只健康杂种犬，基础麻醉后插入双腔气管导管，股动、静脉置管。稳定30分钟（HD0）后，以血定安等速置换全血，分别达到轻度（HD1）、中度（HD2）、重度（HD3）和极重度（HD4）血液稀释四个阶段。每阶段均分为双肺通气（TLV）和单肺通气（ OLV），分别于各阶段TLV、OLV15分钟后测量分流（Qs/Qt)及氧供（DO2）、氧耗（VO2）等各指标变化。结果 随着HD程度的加深，平均动脉压、心输出量、肺血管阻力（PVR）、平均肺动脉压（MPAP）、氧分压、DO2等趋于降低，氧摄取率（EPO2）、血乳酸、Qs/Qt趋于增加，到HD3、HD4时已出现DO2－VO2依赖性降低及无氧酵解征象。与TLV时相比，OLV期间HD0、HD1及HD2组PVR、MPAP增高明显（P＜0．01）。而HD3、H4D4组变化不大（P＞0．05） ；OLV时QS／Qt增加更为明显，HD2、HD3及HD4组分别较基值增加74％、164％及177％（P＜0．01） 。结论 缺氧、ANHD均为影响Qs/Qt与氧合的重要因素，OLV时ANHD应以不低于中度为准。     

比较地氟醚、丙泊酚在单肺通气时对肺内分流的影响

目的　探讨地氟醚与丙泊酚在单肺通气期间对肺内分流、动脉氧分压的影响。方法　30例胸科手术病人 ,随机分为地氟醚组 (D组 ,1MAC)和丙泊酚组 (P组 ,6mg·kg 1·h 1)行循环紧闭麻醉。在手术前分别于平卧位双肺通气 30min、平卧位单肺通气 30min、侧卧位单肺通气 30min ,采集动脉血和混合静脉血行血气分析 ,计算肺内分流率。结果　在单肺通气后 ,D组和P组肺内分流增加明显 (P <0 0 1)。但平卧位分别增加 14 1%和 13 3% (P >0 0 5 ) ,侧卧位分别增加 13 2 %和12 7% (P >0 0 5 ) ,两组间无显著性差异。D组和P组动脉氧分压明显下降 (P <0 0 1) ,且平卧位比侧卧位下降更为明显。结论　 1MAC地氟醚在循环紧闭麻醉单肺通气期间对肺内分流和动脉氧合无明显的抑制。     

单肺通气期间体位对血液氧合的影响

目的比较单肺通气(OLV)期间不同体位对血液氧合及肺内分流的影响。方法15例择期开胸食管癌根治术病人,ASAⅠ~Ⅱ级,于仰卧位双肺通气(TLV)(T1)、仰卧位OLV 30 min(T2),侧卧位开胸前OLV 30 min(T3)分别进行动静脉血气分析,并计算肺内分流率(Qs/Qt)。结果T2与T1比较,动脉血氧分压(PaO2)、混合静脉血氧分压(P-VO2)、动脉血氧饱和度(SaO2)、混合静脉血氧饱和度(S-VO2)和静脉血氧饱和度(CvO2)明显下降,Qs/Qt明显升高(P<0.01),动脉血氧含量(CaO2)明显下降(P<0.05)。T2与T1相比,PaO2明显下降,Qs/Qt明显升高(P<0.01),SaO2明显下降(P<0.05),P-VO2、S-VO2、CaO2和CvO2无明显变化。T2与T3比较,PaO2和S-VO2明显下降,Qs/Qt明显升高(P<0.01)。P-VO2、SaO2和CvO2明显降低(P<0.05)。结论T3较T2能明显改善血液氧合,减少肺内分流。