右美托咪定对全凭静脉麻醉患者单肺通气期间肺内分流及氧合的影响

Effect of dexmedetomidine on intrapulmonary shunt and oxygenation in patients undergoing total intravenous anesthesia during one-lung ventilation

目的 本研究旨在观察右美托咪定对全凭静脉麻醉患者单肺通气期间肺内分流和氧合的影响。方法 选择2016-10/2017-12期间宁夏医科大学总医院择期拟在全麻下行左开胸非肺叶切除患者40例,年龄18~65岁,体质量指数(BMI)18~25 kg/m2, ASA分级Ⅱ或Ⅲ级。随机分为右美托咪定组(D组, n=20)和生理盐水组(C组, n=20)。 D组在麻醉诱导前经静脉泵入右美托咪定负荷剂量(1 μg/kg), 10 min输注完后改为0.4 μg/(kg?h)持续泵注,手术结束前30 min停止用药。 C组泵注相同容量的生理盐水。记录患者麻醉前(T0)、双肺通气(TLV)后20 min(T1)、单肺通气(OLV)后30 min(T2)、单肺通气后1 h(T3)、恢复双肺通气后15 min(T4), 5个时间点的动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、收缩压(SBP)、舒张压(DBP)、平均动脉压(MAP)数值,计算肺内分流率(Qs/Qt)、氧合指数(PaO2/FiO2)、呼吸指数(A-aDO2/PaO2)。结果 两组患者在T0-T4时间点SBP、 DBP、 MAP、 HR组间比较差异无统计学意义,与T0比较C组、 D组患者在T1-T4时间点SBP、 DBP、 MAP、 HR均降低(P<0.05)。两组患者PaCO2组间比较差异无统计学意义。与C组比较, D组患者在T2、 T3时间Qs/Qt、 A-aDO2/PaO2明显降低, PaO2、 PaO2/FiO2明显升高(P<0.05)。与T1时间相比, T2、 T3时2组患者PaO2、 PaO2/FiO2明显降低(P<0.05), Qs/Ot、 A-aDO2/PaO2明显升高(P<0.05)。结论 全凭静脉麻醉患者在单肺通气期间使用右美托咪定可以在一定程度上减少肺内分流,有益于改善术中低氧血症。

Objective To investigate the effect of dexmedetomidine on intrapulmonary shunt and oxygenation in patients undergoing total intravenous anesthesia during one lung ventilation. Methods Forty American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients, aged 18-65 years, with body mass index of 18-25 kg/m2, scheduled for non-lobectomy of left thoracotomy under general anesthesia, in the General Hospital of Ningxia Medical University from October 2016 to December 2017, were included and randomly divided into two groups (n=20 each): Dexmedetomidine group (group D) and Saline group (group C). In group D, dexmedetomidine was intravenously pumped with loading dose (1 μg/kg) before induction of anesthesia. After 10 min of infusion, it was changed to 0.4 μg/(kg?h) for continuous pumping, and stopped 30 min before the end of surgery. The group C was administered same dose of 0.9% saline. ABG was performed before anesthesia (T0), 20 min after TLV (T1), 30 min (T2) and 1 h (T3) after OLV, and 15 min after T2 recovery (T4), then PaO2, Qs/Qt, PaO2/FiO2 and A-aDO2/PaO2 were calculated. Results There were no significant differences in SBP, DBP, MAP and HR between two groups at T0-T4. SBP, DBP, MAP and HR of both groups were significantly lower at T1-T4 than at T0 (P<0.05). There were no significant differences in PaO2 between the two groups at T1-T0. Compared with group C, Qs/Qt, and A-aDO2/PaO2 in group D were significantly lower at T2-T3 (P<0.05). PaO2 and PaO2/FiO2 were significantly increased (P<0.05). PaO2 and PaO2/FiO2 of both groups were significantly decreased at T2-T3, compared with these values at T1. Qs/Qt and A-aDO2/PaO2 were significantly increased in both groups at T2-T3 (P<0.05). Conclusion In patients under intravenous anesthesia, the use of dexamethasone during OLV can reduce intrapulmonary shunt which is beneficial to improving intraoperative hypoxemia.