Zhang Yonghai, Li Bin, Xu Chang, Wu Yan, Ma Ling, Yang Fan, Ma Hanxiang, Ni Xinli
Department of Anesthesiology and Perioperative Medicine, General Hospital of Ningxia Medical University, Yinchuan, China.
Department of Anesthesiology, People's Hospital of Ningxia Hui Autonomous Region, Yinchuan, China.
Front Med (Lausanne). 2025 May 1;12:1574634. doi: 10.3389/fmed.2025.1574634. eCollection 2025.
Inverse ratio ventilation theoretically increases oxygenation in obese patients. However, it is unknown whether the use of inverse ratio ventilation prolongs the safe apnea time during the induction of anesthesia. The primary objective of our study was to compare the safe apnea time between obese surgical patients receiving inverse ratio ventilation and conventional ratio ventilation during the induction of anesthesia.
This study is a prospective, randomized controlled trial. Forty obese patients who underwent elective operation under general anesthesia with endotracheal intubation were randomly allocated into the conventional ratio ventilation (CRV) group ( = 20) and inverse ratio ventilation (IRV) group ( = 20). After the patients were preoxygenated through a face mask for 3 min, anesthesia induction was performed. When the patients lost consciousness and spontaneous breathing disappeared, non-invasive positive pressure ventilation was performed for 5 min, and the inspiratory-to-expiratory (I:E) ratio was set as 1:2 in the CRV group and 2:1 in the IRV group. Heart rate, systolic blood pressure, diastolic blood pressure, and pulse oxygen saturation were recorded at four time points: (i) before pre-oxygenation (T), (ii) pre-oxygenation for 3 min (T), (iii) non-invasive positive pressure ventilation for 3 min (T), and (iv) non-invasive positive pressure ventilation for 5 min (T). Arterial blood was collected at T, T, and T for arterial blood gas analysis, and arterial oxygen partial pressure and carbon dioxide partial pressure were recorded. The patient's expiratory oxygen fraction at T, T, and T were recorded. Peak airway pressure, plateau pressure and mean airway pressure were record at T and T. The safe apnea time was recorded in both groups.
Forty patients completed the study. Baseline parameters were comparable between the two groups. Safe apnea time was significantly longer (210.40 ± 47.47 vs. 153.80 ± 41.54 s, mean difference [95% CI], 56.55 [28.00-85.10], = 0.0003) and the expired O fraction was higher (87.60 ± 2.39 vs. 91.60 ± 1.79, mean difference [95% CI], 4.00 [2.65-5.35], < 0.0001) at T in the IRV group compared to the CRV group.
Volume-controlled inverse ratio ventilation at an I:E ratio of 2:1, compared to conventional ratio ventilation, provided a longer safe apnea time and higher expired O fraction in obese patients during the induction of anesthesia.
反比通气理论上可增加肥胖患者的氧合。然而，在麻醉诱导期间使用反比通气是否会延长安全无呼吸时间尚不清楚。我们研究的主要目的是比较肥胖手术患者在麻醉诱导期间接受反比通气和传统通气比通气时的安全无呼吸时间。
本研究是一项前瞻性、随机对照试验。40例行全身麻醉气管插管择期手术的肥胖患者被随机分为传统通气比组（CRV组，n = 20）和反比通气组（IRV组，n = 20）。患者通过面罩预充氧3分钟后进行麻醉诱导。当患者意识消失且自主呼吸消失时，进行无创正压通气5分钟，CRV组吸气与呼气（I:E）比设定为1:2，IRV组设定为2:1。在四个时间点记录心率、收缩压、舒张压和脉搏血氧饱和度：（i）预充氧前（T₀），（ii）预充氧3分钟时（T₁），（iii）无创正压通气3分钟时（T₂），（iv）无创正压通气5分钟时（T₃）。在T₀、T₁和T₃采集动脉血进行动脉血气分析，记录动脉血氧分压和二氧化碳分压。记录患者在T₁、T₂和T₃时的呼气氧分数。在T₂和T₃记录气道峰压、平台压和平均气道压。记录两组的安全无呼吸时间。
40例患者完成研究。两组基线参数具有可比性。与CRV组相比，IRV组在T₃时的安全无呼吸时间显著更长（210.40 ± 47.47 vs. 153.80 ± 41.54秒，平均差值[95%CI]，56.55[28.00 - 85.10]，P = 0.0003），呼气氧分数更高（87.60 ± 2.39 vs. 91.60 ± 1.79，平均差值[95%CI]，4.00[2.65 - 5.35]，P < 0.0001）。
与传统通气比通气相比，在肥胖患者麻醉诱导期间，I:E比为2:1的容量控制反比通气可提供更长的安全无呼吸时间和更高的呼气氧分数。
