From the Department of Anesthesiology and Critical Care Medicine, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
Division of Anesthesia, Critical Care and Pain, Tel Aviv Medical Center, Sackler School of Medicine, Tel Aviv, Israel.
Anesth Analg. 2019 Mar;128(3):513-522. doi: 10.1213/ANE.0000000000003503.
Intrathecal morphine provides excellent analgesia after cesarean delivery; however, respiratory events such as apnea, bradypnea, and hypoxemia have been reported. The primary study aim was to estimate the number of apneas per subject, termed "apnea alert events" (AAEs) defined by no breath for 30-120 seconds, using continuous capnography in women who underwent cesarean delivery.
We performed a prospective, observational study with institutional review board approval of women who underwent cesarean delivery with spinal anesthesia containing 150-µg intrathecal morphine. A STOP-Bang obstructive sleep apnea assessment was administered to all women. Women were requested to use continuous capnography and pulse oximetry for 24 hours after cesarean delivery. Nasal sampling cannula measured end-tidal carbon dioxide (EtCO2) and respiratory rate (RR), and oxygen saturation (SpO2) as measured by pulse oximetry. Capnography data were defined as "valid" when EtCO2 >10 mm Hg, RR >5 breaths per minute (bpm), SpO2 >70%, or during apnea (AAE) defined as "no breath" (EtCO2, <5 mm Hg) for 30-120 seconds. Individual respiratory variable alerts were 10-second means of EtCO2 <10 mm Hg, RR <8 bpm, and SpO2 <94%. Nurse observations of RR (hourly and blinded to capnography) are reported.
We recruited 80 women, mean (standard deviation [SD]) 35 (5) years, 47% body mass index >30 kg/m2/weight >90 kg, and 11% with suspected obstructive sleep apnea (known or STOP-Bang score >3). The duration of normal capnography and pulse oximetry data was mean (SD) (range) 8:28 (7:51) (0:00-22:32) and 15:08 (6:42) (1:31-23:07) hours:minutes, respectively; 6 women did not use the capnography. There were 198 AAEs, mean (SD) duration 57 (27) seconds experienced by 39/74 (53%) women, median (95% confidence interval for median) (range) 1 (0-1) (0-29) per subject. Observation of RR by nurses was ≥14 bpm at all time-points for all women, r = 0.05 between capnography and nurse RR (95% confidence interval, -0.04 to 0.14). There were no clinically relevant adverse events for any woman. Sixty-five women (82%) had complaints with the capnography device, including itchy nose, nausea, interference with nursing baby, and overall inconvenience.
We report 198 AAEs detected by capnography among women who underwent cesarean delivery after receiving intrathecal morphine. These apneas were not confirmed by the intermittent hourly nursing observations. Absence of observer verification precludes distinction between real, albeit nonclinically significant alerts with capnography versus false apneas. Discomfort with the nasal sampling cannula and frequent alerts may impact capnography application after cesarean delivery. No clinically relevant adverse events occurred.
鞘内注射吗啡可在剖宫产术后提供良好的镇痛效果；然而，已报道出现呼吸暂停、呼吸过缓、低氧血症等呼吸事件。主要研究目的是使用连续二氧化碳描记术估计每位接受剖宫产手术并接受 150-μg 鞘内吗啡的女性的呼吸暂停次数，即通过无呼吸 30-120 秒定义的“呼吸暂停警报事件”（AAE）。
我们进行了一项前瞻性、观察性研究，研究对象为接受脊髓麻醉下剖宫产术的女性，麻醉中含有 150-μg 鞘内吗啡。对所有女性进行 STOP-Bang 阻塞性睡眠呼吸暂停评估。要求女性在剖宫产术后 24 小时内使用连续二氧化碳描记术和脉搏血氧饱和度监测仪。鼻采样管测量呼气末二氧化碳（EtCO2）和呼吸频率（RR），以及脉搏血氧饱和度（SpO2），由脉搏血氧饱和度仪测量。当 EtCO2 >10 mm Hg、RR >5 次/分钟（bpm）、SpO2 >70%或出现呼吸暂停（AAE）定义为“无呼吸”（EtCO2，<5 mm Hg）30-120 秒时，定义为“有效”的二氧化碳描记术数据。个别呼吸变量警报为 10 秒 EtCO2 <10 mm Hg、RR <8 bpm 和 SpO2 <94%的平均值。报告护士观察到的 RR（每小时和对二氧化碳描记术盲法）。
我们招募了 80 名女性，平均（标准差[SD]）年龄为 35（5）岁，47%的体重指数>30 kg/m2/体重>90 kg，11%的人怀疑患有阻塞性睡眠呼吸暂停（已知或 STOP-Bang 评分>3）。正常二氧化碳描记术和脉搏血氧饱和度数据的持续时间分别为平均（SD）（范围）8:28（7:51）（0:00-22:32）和 15:08（6:42）（1:31-23:07）小时：分钟；有 6 名女性未使用二氧化碳描记术。有 198 次 AAE，53%的女性经历了 39/74 名女性的 57（27）秒的持续时间，中位数（95%置信区间中位数）（范围）1（0-1）（0-29）次/受试者。所有女性在所有时间点的护士观察到的 RR 均≥14 bpm，二氧化碳描记术和护士 RR 之间的相关性为 r = 0.05（95%置信区间，-0.04 至 0.14）。没有任何女性出现任何临床相关不良事件。65 名女性（82%）对二氧化碳描记术设备有抱怨，包括鼻子瘙痒、恶心、干扰护理婴儿和整体不便。
我们报告了 198 次通过二氧化碳描记术检测到的接受鞘内吗啡后剖宫产术后女性的呼吸暂停事件。这些呼吸暂停未通过每小时的护士间歇性观察得到证实。由于缺乏观察者的验证，因此无法区分二氧化碳描记术与真实但无临床意义的警报之间的真正呼吸暂停与假呼吸暂停。对鼻采样管的不适和频繁的警报可能会影响剖宫产术后的二氧化碳描记术应用。没有发生任何临床相关的不良事件。
