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.     

单肺麻醉的研究现状

单肺麻醉即单肺通气(OLV)麻醉,目的在防止血液或分泌物流向健侧肺;为手术操作提供相对静止的手术野。但是,OLV时,无通气侧肺的血液没有得到氧合就回到左心,可致静脉血掺杂,PaO2降低;无通气侧肺泡的低氧可致低氧性肺血管收缩(HPV),使非通气侧肺血流减少并转向通气肺,由此使QS/QT减少,PaO2降低有所改善,但仍有约10％的病人发生显着低氧血症。所以,如何降低OLV时的QS／QT和怎样提高PaO2是单肺麻醉的关键问题。     

单肺通气中低氧血症的防治进展

单肺通气为剖胸手术提供了良好的手术条件,但因其引起低氧血症的发生率高,威胁病人的安全,是对麻醉医 生的重大挑战。本文介绍了单肺通气中低氧血症的原因及其防治方法进展。     

单肺通气方法和低氧血症防治

单肺通气（简称ＯＬＶ）的主要目的是为了防止病侧肺的分泌物或血液流入对侧肺，确保气道通畅和避免交叉感染或病灶扩散，同时为手术创造有利条件。本文结合近年的研究进展对此进行简要介绍。ＯＬＶ适应证目前临床适应证包括以下几方面：①湿肺：尤其是每天痰量＞１５ｍｌ...     

单肺通气中低氧血症的防治进展

单肺通气为剖脑手术提供了良好的手术条件，但因其引起低氧血症的发生率高，威胁病人的安全，是对麻醉医生的重大挑战。本文介绍了单肺通气中低氧血症的原因及其防治方法进展。     

小剂量乌拉地尔对单肺通气期间动脉氧合及血流动力学的影响

目的 观察小剂量乌拉地尔对单肺通气(OLV)期间动脉氧合及血流动力学的影响.方法 择期行食管癌根治术患者100例,随机均分为两组,分别在OLV期间持续静脉输注乌拉地尔4 μg· kg-1 ·min-1(U组)和等容量生理盐水(C组).记录两组双肺通气20 min(T0)、OLV 20 min (T1)、30 min(T2)、45 min(T3)、60min(T4)时的氧合指标及血流动力学指标.结果 与T0时比较,T1～T4时两组患者PaO2均明显降低,Qs/Qt明显升高(P＜0.01).与T1时比较,T3、T4时U组患者PaO2显著升高,Qs/Qt显著降低(P＜0.05) ;T4时C组患者PaO2明显升高,Qs/Qt明显降低(P＜0.05).与C组比较,T3、T4时U组患者PaO2明显升高,Qs/Qt明显降低(P＜0.05).两组各时点MAP、HR差异无统计学意义.结论 小剂量乌拉地尔可改善OLV期间动脉氧合,减少肺内分流,但对血流动力学无明显影响.     

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。     

单肺通气预测PaO2的临床评价

单肺通气 (ＯＬＶ)时 ,由于肺内分流的增加 ,造成动静脉血掺杂 ,从而使ＰａＯ2 降低 ,约有 10 %的病人可发生显著低氧血症[1] 。ＯＬＶ麻醉前预测ＰａＯ2 ,对于病人低氧血症的预防和治疗显得尤为重要。我们就Ｓｌｉｎｇｅｒ等[2 ] 提出的预测ＯＬＶ时ＰａＯ2 的公式作了临床验证 ,现报告如下。资料与方法一般资料　选择ＡＳＡⅠ～Ⅱ级的择期开胸手术病人 30例 ,男 2 4例 ,女 6例 ,平均年龄 5 3岁。右侧开胸 13例 ,左侧开胸 17例。肺手术 18例 ,非肺手术 12例。肺功能正常 16例 ,轻至中度混合性通气功能障碍 14例。麻醉方法　术前肌注苯巴比…     

丙泊酚对大鼠单肺通气缺氧性肺血管收缩及肺泡气体交换的影响

目的观察丙泊酚对大鼠单肺通气急性缺氧性肺血管收缩（HPV）以及氧合的影响。方法 40只SD大鼠随机均分为四组:空白组（灌注液组,P₁组）、灌注液加入丙泊酚36mg/L组（P₂组）、24mg/L组（P₃组）、12mg/L组（P₄组）。双肺通气记录流量-压力曲线,利用非线性回归计算肺血管膨胀系数（α）和固有阻力（R₀）。随后行单肺通气,记录单肺通气肺动脉压（PAP）及流出液PO₂,并计算各组的PAP百分比（△PAP%）、PO₂百分比（△PO₂%）。结果△PAP%P₁组高于其它三组,而P₄组高于P₂组（P<0.01或P<0.05）;单肺P₂组氧合指数（OI）显著低于其它三组（P<0.01）;四组单肺OI显著低于同组双肺OI（P<0.01）;P₂组△PO₂%显著高于其它三组（P<0.05）。结论丙泊酚剂量依赖性抑制单肺通气的HPV,但气体交换功能只有在达到一定的程度方受影响。     

A coaxial technique for facilitating one-lung ventilation

A tube for bronchial intubation is described. A long (48 cm), small bore (5.0 mm internal diameter), cuffed, bronchial plastic tube is inserted coaxially within a large bore tracheal tube (10.0 mm) used for ventilation. The inner tube is designed primarily as a blocker to be inserted with a fibreoptic or optical bronchoscope, but can be effected blindly with a stylet. Several methods of inserting the inner tube and ensuring correct placement were used in 10 males undergoing thoracic surgery. If the bronchial cuff is inflated the tube can be used either as a blocker or as a conduit for suction and conventional and differential ventilatory techniques. Early clinical experience suggests that the technique is an alternative method of facilitating one-lung ventilation.     

单肺通气时PETCO2与PaCO2的关系

对２６例ＡＳＡＩ～Ⅱ级开胸肺手术的患者，分为Ａ、Ｂ两组，分别以双肺通气（ＴＬＶ）为对照行单肺通气（ＯＴＶ）或ＯＴＶ ＋术侧肺用Ｂａｉｎ回路行ＣＰＡＰ，测量ＴＬＶ３０分，ＯＬＶ３０分、６０分和Ｒ－ＴＬＶ３０分的ＰＥＴＣＯ２和ＰａＣＯ２值，观察两者的关系。结果表明，两组中ＯＬＶ时的ＰＥＴＣＯ２和ＰａＣＯ２均正常，但较ＴＬＶ时有升高的趋势（Ｐ＜０．０５），Ｒ－ＴＬＶ后又复原（Ｐ＞０．０５）；两组间ＯＬＶ时的测量值无差异（Ｐ＞０．０５），而ＰＥＴＣＯ２与Ｐ。ＣＯ２有密切的相关性（Ｐ＜０．０５）；Ｐ（ａ－ＥＴ）ＣＯ２和ＰＥＴＣＯ２的计算值在不同通气时无显著性差异，说明ＰＥＴＣＯ２可作为一种无创监测手段指导ＯＬＶ时的通气效果。     

Performance of electrical impedance tomography in detecting regional tidal volumes during one-lung ventilation

Background: Electrical impedance tomography (EIT) is becoming a new medical imaging modality for continuous monitoring of regional lung function in the intensive care unit or operating room. The aim of our study was to evaluate the performance of EIT in detecting regional tidal volumes in patients during volume-controlled mechanical ventilation of one or both lungs.
Methods: Ten adult patients undergoing elective thoracic surgery were included. EIT measurements were performed with the Goe-MF II EIT system. Data were collected before surgery during ventilation of both, the right and left lungs. Tidal volumes of 800 and 400 ml were applied during bilateral and unilateral ventilation, respectively.
Results: Ventilation-related impedance changes determined in the whole chest cross-section during the right and left lung ventilation did not significantly differ from each other and were equal to 47.6±5.6% and 48.5±7.8% (mean±SD) of the value determined during bilateral ventilation. During unilateral ventilation, EIT clearly separated the ventilated and non-ventilated lung regions; nevertheless, ventilation-related impedance changes were also detected at the non-ventilated sides in areas corresponding to 3.4±4.1% and 12.4±6.9% of the scan halves during ventilation of the left and right lung, respectively. Changes in global tidal volumes were adequately detected by EIT during both bilateral and unilateral lung ventilation.
Conclusion: Although good separation of the ventilated and non-ventilated sides of the chest was possible, the data indicate that reliable quantification of regional tidal volumes during asymmetric or inhomogeneous distribution patterns requires regions-of-interest analysis.     

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.     

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.     

帕瑞昔布钠对单肺通气患者术后早期认知功能的影响

目的：探讨帕瑞昔布钠对单肺通气（One-lung ventilation,OLV）患者术后早期认知功能的影响。方法选择择期全麻下行 OLV 肺叶切除术患者60例,并将60例随机分为对照组（C组）和帕瑞昔布钠组（P 组）,每组30例。全麻诱导前30 minP 组患者静脉给予帕瑞昔布钠40 mg,C组患者给予等体积的生理盐水。采集麻醉诱导前30 min（T0）、OLV 即刻（T1）、OLV 30 min（T2）、OLV 60 min（T3）、膨肺后30 min（T4）、术后120 min（T5）6个时间点桡动脉和颈内静脉球部血行血气分析,并计算脑氧摄取率（CERO2）,记录乳酸含量。酶联免疫吸附（ELISA 法）检测血浆肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）含量,于术前1 d、术后1 d、术后3 d 及术后7 d 采用简易智能量表（MMSE）行认知功能评分。结果与 T0时点比较,两组患者血乳酸含量 T2、T3、T4时点明显升高（P ＜0．05或0．01）。P 组患者血乳酸含量在 T3和 T4时点分别为（1．79±0．47）mmol／L 和（1．64±0．49）mmol／L,与 C 组比较明显下降（P ＜0．05）;TNF-α水平在 T1、T2、T3、T4和 T5时点分别为（9．53±2．17）pg／ml、（10．21±1．73）pg／ml、（12．58±2．32）pg／ml、（10．54±1．86）pg／ml 和（7．39±1．25）pg／ml,与 C 组比较明显下降（P ＜0．05）,IL-6水平 T1、T2、T3、T4和 T5分别为（39．46±10．54）pg／ml、（37．87±15．05）pg／ml、（53．57±15．56）pg／ml、（47．74±13．53）pg／ml 和（38．68±11．41）pg／ml,与 C 组比较明显下降（P ＜0．05）。与 T0时点比较,两组患者 CERO2值于T2、T3时点明显升高（P ＜0．05）。术后7 d,P 组患者认知功能障碍发生率为15．0％,C 组为26．0％,两组比较差异有统计学意义（P ＜0．05）。结论帕瑞昔布钠可降低 OLV 患者术后早期认知功能障碍的发生率,其机制可能与降低围术期血乳酸含量、抑制机体炎性反应有关。     

Low dose methylprednisolone prophylaxis to reduce inflammation during one-lung ventilation

Background: The specific aim of this study was to examine the efficacy of a low dose of methylprednisolone in minimizing inflammatory response in juvenile piglets when given 45–60 min prior to onset of one‐lung ventilation. Methods: Twenty piglets aged 3 weeks were assigned to either the control group (n = 10) or methylprednisolone group (n = 10). The animals were anesthetized and after 30 min of ventilation, they had their left lung blocked. Ventilation was continued via right lung for 3 h. The left lung was then unblocked. Following another 30 min of bilateral ventilation, the animals were euthanized and both lungs were harvested. The methylprednisolone group had a single dose (2 mg·kg^?1) of methylprednisolone given i.v. 45–60 min prior to onset of one‐lung ventilation. Physiological parameters (PaO₂, resistance, and compliance) and markers of inflammation (tumor necrosis factor [TNF]‐α, interleukin [IL]‐1β, IL‐6, and IL‐8) were measured at baseline and every 30 min thereafter. Lung tissue homogenates from both collapsed and ventilated lungs were analyzed for TNF‐α, IL‐1β, IL‐6, and IL‐8. Results: The methylprednisolone group had higher partial pressure of oxygen (P = 0.01), lower plasma levels of TNF‐α (P = 0.03) and IL‐6 (P = 0.001) when compared with control group. Lung tissue homogenate in the methylprednisolone group had lower levels of TNF‐α (P < 0.05), IL‐1β (P < 0.05), and IL‐8 (P < 0.05) in both the collapsed and the ventilated lungs. Conclusions: In a piglet model of one‐lung ventilation, use of prophylactic methylprednisolone prior to collapse of the lung improves lung function and decreases systemic pro‐inflammatory response. In addition, in the piglets who received methylprednisolone, there were reduced levels of inflammatory mediators in both the collapsed and ventilated lungs.