围术期氧耗量的再评估

2020

12/11

米勒之声

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对围手术期VO2变化的评估在以前的文献中是不确定的，并且在当前高风险的外科人群中具有有限的普遍性。

本文由“小麻哥的日常”授权转载

围术期氧耗量的再评估：

一项对接受腹部大手术的老年患者的观察性研究

背景

腹部大手术中旨在优化氧气输送(DO₂)的围手术期血流动力学算法没有推荐、也不包括氧耗量(VO₂) 监测。对围手术期VO₂变化的评估在以前的文献中是不确定的，并且在当前高风险的外科人群中具有有限的普遍性。在一项前瞻性的非干预观察性研究中，我们调查了老年腹部手术病人在麻醉诱导后VO₂的变化，以及术中和术后DO₂相关的VO₂变化，并通过常规监测评估氧的摄取率(O₂ER)。

方法

在20名65岁以上、ASAII～IV、择期硬膜外联合全身麻醉行开放性上腹部手术的患者中采用间接量热法(QuarkRMR) 测定VO₂。在手术前20分钟、麻醉诱导后、术中和术后收集数据。同时，使用LiDCOplus 监测DO₂。根据动脉-中心静脉血氧含量计算氧的摄取率(O₂ER)。采用混合模型分析围手术期的变化。

结果

VO2在麻醉诱导后平均减少34% (95% CI: 28～39)。术后2小时，VO₂比清醒时减少24% (95% CI: 20 ~ 27)。术前DO₂平均为440(95% CI: 396~483) ml·min^-1·m^-2，麻醉期间DO₂平均下降37% (95%CI: 30～43)。评估的O₂ER无变化，术中为0.24(95%CI: 0.21～0.26)，术后增加到0.31(95% CI: 0.27～0.36)。术中 VO₂的变化与 DO₂和 O₂ER 的变化是平行的。

结论

全身麻醉使接受腹部大手术的老年病人的 VO₂减少了大约三分之一。术中VO₂和DO₂呈平行变化，且氧摄取量低。这些变化的相关性需要将结果和血流动力学干预措施相结合作进一步评估。

Peri-operative oxygen consumption revisited

An observational study in elderly patientsundergoing major abdominal surgery

BACKGROUND

Monitoring oxygen consumption (VO₂) is neither recommended nor included in peri-operativehaemodynamic algorithms aiming at optimising oxygen delivery (DO₂) in major abdominal surgery. Estimates of peri-operative VO₂ changes are uncertain in earlier publications and havelimited generalisability in the current high-risk surgical population. In aprospective non-interventional observational study in elderly patientsundergoing major abdominal procedures, we investigated the change of VO₂ after induction of anaesthesia and secondarily, thefurther changes during and after surgery in relation to DO₂ and estimated oxygen extraction ratio (O₂ER) by routine monitoring.

METHODS

VO₂ wasdetermined by indirect calorimetry (QuarkRMR) in 20 patients more than 65 years(ASA II to IV), scheduled for elective open upper abdominal surgery with combinedepidural and general anaesthesia. Data were collected during 20-minute periodspre-operatively and after anaesthesia induction, with subsequent measurementsduring surgery and postoperatively. Simultaneously, DO₂ was monitored using LiDCOplus. The O₂ER was estimated from arterial–central venous oxygen contentcalculation. Mixed models were used to analyse the peri-operative changes.

RESULTS

VO₂ decreasedafter induction of anaesthesia by a mean of 34% (95% CI, 28 to 39). After 2 hof surgery, VO₂ wasreduced by 24% (95% CI, 20 to 27) compared with the awake baselinemeasurements. Pre-operative mean DO₂ was 440 (95% CI, 396 to 483) ml min⁻¹ m⁻² anddecreased by a mean of 37% (95% CI, 30 to 43) during anaesthesia. The estimatedO₂ER didnot change intra-operatively 0.24 (95% CI, 0.21 to 0.26) but increasedpostoperatively to 0.31 (95% CI, 0.27 to 0.36). The changes of VO₂ were parallel with changes of DO₂ and O₂ER inthe intra-operative period.

CONCLUSION

General anaesthesia reduced VO₂ by approximately a third in elderly patients undergoingmajor abdominal surgery. Parallel changes of intra-operative VO₂ and delivery were demonstrated while oxygen extraction waslow. The relevance of these changes needs further assessment in relation tooutcomes and haemodynamic interventions.