Mutetwa E N, Shumbairerwa S, Crawford A, Madzimbamuto F D, Chimoga T, Marange-Chikuni D
Cent Afr J Med. 2015 Sep-Dec;61(9-12):61-5.
Acid base alterations occur during laparoscopy with carbon dioxide insufflation. The purpose of this study was to investigate the effects of low tidal volume ventilation on acid base status during pneumoperitonium.
30 patients undergoing laparoscopic surgery under General Anaesthesia were ventilated with tidal volume of 6 ml/kg and respiratory rate of 12 breaths/minute. Arterial blood gas analysis was done before, during and after C02 pneumoperitoneum. Arterial haemoglobin oxygen saturation by pulse oximetry (SPO2) and EtC02 were monitored continuously throughout the laparoscopy. Respiratory adjustments were done for EtCO2 levels above 60mmHg or SPO2 below 92% or adverse haemodynamic changes.
low tidal volume ventilation during pneumoperitoneum resulted in a significant elevation in PaCO2 (p<0.001) and a fall of pH (p <0.001), ion bicarbonate (HCO3-) (p = 0.011), and base excess (ABE) (p <0.001). A correlation was found between the EtCO2 and PaCO2 during pneumoperitoneum. Oxygenation was well maintained during pneumoperitoneum. No ventilatory adjustments were instituted on any of the patients as they maintained EtCO2 below 60mmHg throughout pneumoperitoneum.
Ventilation with low tidal volume during pneumoperitoneum causes a mixed respiratory and metabolic acidosis. EtCO2 is still a good non-invasive monitor for estimation of PaCO2 during low tidal volume ventilation during pneumoperitoneum.
腹腔镜二氧化碳气腹手术过程中会发生酸碱改变。本研究的目的是调查低潮气量通气对气腹期间酸碱状态的影响。
30例接受全身麻醉的腹腔镜手术患者采用6 ml/kg潮气量和12次/分钟呼吸频率进行通气。在二氧化碳气腹前、气腹期间和气腹后进行动脉血气分析。在整个腹腔镜手术过程中持续监测脉搏血氧饱和度（SPO2）测定的动脉血红蛋白氧饱和度和呼气末二氧化碳（EtCO2）。对于EtCO2水平高于60mmHg或SPO2低于92%或出现不良血流动力学变化的情况进行呼吸调整。
气腹期间低潮气量通气导致动脉血二氧化碳分压（PaCO2）显著升高（p<0.001），pH值、离子碳酸氢盐（HCO3-）（p = 0.011）和碱剩余（ABE）下降（p <0.001）。气腹期间发现EtCO2与PaCO2之间存在相关性。气腹期间氧合维持良好。由于所有患者在整个气腹期间EtCO2均维持在60mmHg以下，因此未对任何患者进行通气调整。
气腹期间低潮气量通气会导致混合性呼吸性和代谢性酸中毒。EtCO2仍然是气腹期间低潮气量通气时估计PaCO2的良好无创监测指标。
