Sreejit Melveetil S, Ramkumar Venkateswaran
Department of Anaesthesiology, MES Medical College and Hospital, Perinthalmanna, Malappuram, Kerala, India.
Department of Anaesthesiology, Kasturba Medical College, Manipal, Karnataka, India.
Indian J Anaesth. 2015 Apr;59(4):216-21. doi: 10.4103/0019-5049.154998.
Induction of general anaesthesia per se as also the use of 100% oxygen during induction of anaesthesia, results in the development of atelectasis in dependent lung regions within minutes of anaesthetic induction. We aimed to assess the effect of application of a continuous positive airway pressure (CPAP) of 5 cm H2O during pre-oxygenation and induction of anaesthesia on the period of apnoea before the occurrence of clinically significant desaturation.
In this prospective, randomised, and double-blind study, 40 patients posted for elective surgery were enrolled. Duration of apnoea was measured as the time from the administration of succinylcholine hydrochloride to the time when oxygen saturation fell to 93%. Student's t-test was used for comparing the duration of apnoea.
The safe duration of apnoea was found to be significantly longer in patients receiving CPAP of 5 cm H2O (Group P; n = 16) compared to the group receiving no CPAP (Group Z; n = 20), that is, 496.56 ± 71.68 s versus 273.00 ± 69.31 s (P < 0.001).
The application of CPAP of 5 cm H2O using a Mapleson A circuit with a fixed positive end-expiratory pressure device during 5 min of pre-oxygenation with 100% oxygen prior to the induction of anaesthesia provides a clearly longer duration of apnoea before clinically significant arterial desaturation occurs.
全身麻醉诱导本身以及麻醉诱导期间使用100%氧气，会在麻醉诱导数分钟内导致依赖肺区出现肺不张。我们旨在评估在预给氧和麻醉诱导期间应用5 cm H₂O的持续气道正压通气（CPAP）对临床显著去饱和发生前的呼吸暂停时间的影响。
在这项前瞻性、随机、双盲研究中，纳入了40例择期手术患者。呼吸暂停持续时间定义为从给予盐酸琥珀酰胆碱到氧饱和度降至93%的时间。采用学生t检验比较呼吸暂停持续时间。
发现接受5 cm H₂O CPAP的患者（P组；n = 16）的安全呼吸暂停持续时间明显长于未接受CPAP的组（Z组；n = 20），即496.56 ± 71.68秒对273.00 ± 69.31秒（P < 0.001）。
在麻醉诱导前用含固定呼气末正压装置的Mapleson A回路进行5分钟100%氧气预给氧期间应用5 cm H₂O的CPAP，可在临床显著动脉去饱和发生前提供明显更长的呼吸暂停持续时间。
