The physiological effects of carbon dioxide (CO2) insufflation in laparoscopic surgery have been well studied [1]. The pneumoperitoneum causes cardiovascular and respiratorypathophysiology which includes a decrease in venous return, ejection fraction, stroke volume and functional residual capacity, as well as an increase in ventilatory pressures, hypoxemia and hypercarbia [2]. Most of these effects will revert back to normal upon deflation of the abdomen. Intrathoracic insufflation of CO2increases central venous pressure and pulmonary capillary wedge pressure, decreases cardiac index and cause tachycardia [3]. Due to these changes the use of high insufflation pressures (8-12 mm Hg) during thoracoscopy has been cautioned against in hypovolemic patients and those with poor left ventricular function [4]. The effect of CO2insufflation in thoracoscopic surgery on respiratory physiology has however not been extensively documented. Studies in either patients with minimal pulmonary disease undergoing cardiac surgery [5,6] or healthy patients undergoing thymectomy [7] or thoracoscopy [8], either found no abnormalities in arterial or end tidal CO2(ETCO2) or a rise of 10 mm Hg or less but focused on the hemodynamic effects.The use of CO2insufflation is not considered the standard surgical exposure for thoracoscopic surgery for thoracic resections. More commonly passive lung deflation is used with the exception of pediatric patients [9,10,11].The respiratory effects of passive lung deflation with one lung ventilation (OLV) for thoracic resections have been documented previously [12,13]. These studies noted problems with oxygenation but no difficulties with ventilation. The surgeons at our institution however feel strongly that the use of thoracic CO2insufflation provides better visualization in adults and it is the predominant method used by them [14].As anaesthesiologists we were unsure of the ventilatory effects of CO2insufflation in an older patient population with coexisting lung pathology undergoing thoracoscopic surgery. Our goal was therefore to evaluate perioperative ETCO2and PaCO2as well as capture any clinically significant complications of hypercarbia in patients undergoing thoracoscopic surgery with CO2insufflation.
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机译：腹腔镜手术中二氧化碳（CO2）吹入的生理效应已得到充分研究[1]。气腹会引起心血管和呼吸道病理生理，包括静脉回流，射血分数，中风量和功能残余能力的降低，以及通气压力，低氧血症和高碳血症的增加[2]。腹部放气后，大多数这些影响将恢复正常。胸腔内注入二氧化碳会增加中心静脉压和肺毛细血管楔压，降低心脏指数并引起心动过速[3]。由于这些变化，在低血容量患者和左心室功能较差的患者中，在胸腔镜检查时应注意避免使用高吹气压力（8-12 mm Hg）[4]。然而，胸腔镜手术中二氧化碳吹入对呼吸生理的影响尚未得到广泛记录。对接受心脏外科手术的极少肺部疾病患者[5,6]或进行胸腺切除术[7]或胸腔镜检查[12]的健康患者的研究，均未发现动脉或潮气末CO2（ETCO2）异常或升高10 mm Hg或更少，但主要集中在血液动力学效应上。CO2吹入法不被视为胸腔镜手术进行胸腔切除术的标准手术暴露量。除小儿患者外，更常见的是被动肺通气[9,10,11]。胸腔切除术中被动肺通气伴一肺通气（OLV）的呼吸作用已有文献报道[12,13]。这些研究指出了充氧问题，但通气没有困难。但是，我们机构的外科医生强烈感到，使用胸腔内二氧化碳注入技术可以使成年人更好地进行可视化，这是他们使用的主要方法[14]。作为麻醉师，我们不确定在并存的老年患者中进行二氧化碳注入的通气效果正在进行胸腔镜手术的肺部病理。因此，我们的目标是评估胸腔镜手术中CO2注入患者的围手术期ETCO2和PaCO2以及捕获任何临床上明显的高碳酸血症并发症。
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