试验剂量芬太尼在预测术后持续吗啡静脉镇痛患者发生呼吸抑制的可能性

目的:评估试验剂量芬太尼所致低氧血症在预测术后吗啡静脉镇痛患者镇痛效果及发生呼吸抑制可能性中的作用。方法:在35例准备术后使用吗啡持续静脉镇痛(12μg·kg~(-1)·h~(-1))的患者术前静脉注射2μg/kg的芬太尼。结果:在吸空气状态下芬太尼注入后,有19人血氧饱和度(SpO_2)降至95％以下,16人SpO_2仍维持在95％或以上。在SpO_2降至95％以下的19例患者,术后使用吗啡持续静脉镇痛时,有8人在术后24或40 h清醒状态下发生呼吸抑制(SpO_2<95％),而在使用芬太尼后SpO_2大于或等于95％的患者中,无一人发生呼吸抑制(P<0.01)。术前使用芬太尼后最低的SPO_2与术后24和40 h的最低SpO_2显著相关(P<0.01),但与术后8、16、24和40 h时的镇痛效果无关(P>0.05)。结论:术前静脉注射芬太尼易致脱氧的患者,术后使用吗啡持续静脉镇痛时易于发生呼吸抑制,但其镇痛效果不一定好。

The Effect of Test Dose Fentanyl on Predicting Postoperative Respiratory Depression in Patients with Continuous Intravenous Morphine Analgesia

Objective: To evaluate the effect of test dose fentanyl on predicting postoperative analgesia and respiratory depression. Methods: Preoperatively the lowest pulse oximeter saturation ( SpO2 ) under room air breathing was measured after 2μg/kg of fentanyl given intravenously in 35 patients who were scheduled with continuous intravenous morphine analgesia(12μg@kg-1@h-1) postoperatively. Results: The test dose fentanyl resulted in respiratory depression in 19 of 35 cases, while 8 (42.1%) of the 19 cases developed respiratory depression postoperatively. However in the rest 16 patients, no patient (0) developed respiratory depression(P＜0.01 ). The fentanyl-induced lowest SpO2 significantly correlated with the lowest SpO2 postoperatively (P＜0.01). The analgesia effect in terms of verbal analogue scale was correlated neither with the fentanyl-induced lowest SpO2 nor with the lowest SpO2 postoperatively ( P＞0.05). Conclusion: The patient who was sensitive to fentanyl-induced respiratory depression would take a high risk to develop postoperative respiratory depression with intravenous morphine analgesia and the patient with respiratory depression does not always go with satisfactory analgesia.