【摘要】 目的 观察单肺通气期间不同通气模式在小儿仰卧位非胸部手术时呼吸力学、血液动力学、动脉血氧分压的改变。方法 选择34例小儿,ASA Ⅰ-Ⅱ级,下腹部及四肢择期手术,麻醉诱导气管插管后,仰卧位,先行双肺通气,采用定容模式(TLV-VCV)潮气量为8-10 ml/kg,再行右侧单肺通气,采用定容模式(OLV-VCV),25 min后改为单肺定压通气(OLV-PCV),压力设定根据单肺定容的气道平台压而定。用旁气流通气监测法(SSS)监测呼吸力学参数:气道峰压(Ppeak)、气道平台压(Pplat)、气道阻力(Raw)、动态胸肺顺应性(Cdyn)、分钟通气量(MV)等,其中18例年龄>5岁、体重15kg以上患儿采用经食道超声多普勒监测仪监测血液动力学参数:心输出量(CO)、每搏量(SV)、外周血管阻力(SVR)、左心射血时间(INETi)、主动脉血流加速度(ACC)和主动脉血流速度(ABF),并取动脉血作血气分析(PaO2、PaCO2)。结果 OLV-VCV与TLV-VCV相比,Ppeak、Pplat、Raw明显升高(P<0.01),而Cayn、CO、SV下降(P<0.05-0.01),SVR明显升高(P<0.05),PaO2下降(P<0.01)。OLV-PCV与OLV-VCV比较,PaO2升高(P<0.05)。结论小儿单肺通气期间采用定压通气模式有利于改善肺泡氧合,减轻单肺通气造成的血氧分压下降。更多还原

【Abstract】 Objective To investigate the effect of different modes of one-lung ventilation ( OLV) on respiratory mechanics, hemodynamics and arterial oxygen tension ( PaO2) in pediatric patients. Methods Thirty-four ASA Ⅰ - Ⅱ patients (14 male, 20 female) aged 2-10 yr, weighing 8-26 kg undergoing abdominal surgery or operations on extremities were enrolled in this study. The patients were premedicated with intramuscular phenobarbital 2-3 mg · kg-1 and atropine 0.015 mg · kg-1 . In the operating room the patients were given intramuscular midazolam 0.25 mg· kg-1 and ketamine 2.5 mg · kg-1 before intravenous line and EGG, NIBP and SpO2 monitoring were established. Anesthesia was induced with intravenous fentanyl 3-5 μg kg-1 and vecuronium 0.1 mg· kg-1 and maintained with isoflurane inhalation supplemented with intermittent iv boluses of fentanyl and vecuronium. In patients aged over 5 yr Univent (Fuji Corpi) was inserted and left main bronchus was blocked during OLV. In patients less than 5 yr ordinary tracheal tube was inserted and was advanced into right main bronchus during OLV. Correct positioning of the tube was checked by fiberoptic bronchoscopy or auscultation. The test consisted of three steps : firstly two-lung ventilation (TLV) with volume-control mode; secondly OLV with volume-control mode;lastly OLV with pressure-control mode. During first and second step VT was set at 8-10 ml kg-1 and respiratory rate was adjusted to maintain PETCO2 between 4.5-6.0 kPa. During the third step (OLV with pressure-control mode) the inspiratory pressure was set according to the plateau pressure during step 1 and 2 (volume-control mode). Each step was maintained for 25 min before respiratory mechanics , hemodynamics and PaO2 were measured and recorded.Results During OLV with volume-control mode (second step) , peak pressure (Ppeak), plateau pressure (Pplat) and airway resistance (Raw) were significantly higher but dynamic compliance was significantly lower, cardiac output (CO) and stroke volume (SV) were significant lower but systemic vascular resistance (SVR) was significantly higher and PaO2 was significantly lower than those during first step (two lung ventilation with volume-control mode) (P<0.01 or 0.05). During third step (OLV with pressure-control mode) Pa02 was significantly increased as compared with that during second step ( P < 0.01). Conclusion During OLV, pressure-control mode provides better alveolar ventilation with higher PaO2 than volume-control mode in pediatric patients.更多还原