小潮气量过度通气对俯卧位脊柱手术患者眼内压和颅内压的影响:一项双盲随机对照试验

Small tidal volume hyperventilation relieves intraocular and intracranial pressureelevation in prone spinal surgery:a randomized controlled trial

目的探讨不同通气模式对全麻俯卧位脊柱手术患者眼内压及颅内压的影响。方法选择2022年11月~2023年6月接受全麻下俯卧位脊柱手术患者,随机纳入常规通气组(n=36)与小潮气量过度通气组(n=36)。常规通气组Vt 8 mL/kg,Fr 12~15/min,维持etCO_(2)在35~40 mmHg;小潮气过度通气组Vt 6 mL/kg,Fr 18~20/min,维持etCO_(2)在30~35 mmHg。以手持式眼压计测量双眼眼内压(IOP),以床旁实时超声在眼球后3 mm处测量视神经鞘直径(ONSD),分别在麻醉前(T0),麻醉完成即刻(T1),俯卧位摆放即刻(T2),手术进行2 h(T3),术毕转至平卧位即刻(T4),术后30 min(T5)记录IOP、ONSD以及循环及呼吸指标,进行组间及组内比较,同时分析二者的相关影响因素。结果与T1相比,两组患者在T3、T4时刻IOP与ONSD均显著上升(P<0.05),过度通气组IOP测值在T3、T4时明显低于常规通气组(P<0.05),ONSD值在T4时低于常规通气组(P<0.05);相关性分析发现IOP与手术时长(r=0.779,P<0.001)及术中etCO_(2)呈现相关[r=-0.248(T3),P<0.001;r=-0.251(T4),P<0.001],ONSD仅与手术时长有关(r=0.561,P<0.05),而IOP与ONSD二者间无明显相关性[r=0.178(T3),P>0.05;r=0.165(T4),P>0.05]。结论全麻下俯卧位脊柱手术可显著增加患者IOP与ONSD,过度通气模式可以一定程度缓解俯卧位手术所致IOP与ONSD升高。

Objective To investigate the effects of different ventilation strategies on intraocular pressure(IOP)and intracranial pressure in patients undergoing spinal surgery in the prone position under general anesthesia.Methods Seventy-two patients undergoing prone spinal surgery under general anesthesia between November,2022 and June,2023 were equally randomized into two groups to receive routine ventilation(with Vt of 8mL/kg,Fr of 12-15/min,and etCO_(2)maintained at 35-40 mmHg)or small tidal volume hyperventilation(Vt of 6 mL/kg,Fr of18-20/min,and etCO_(2)maintained at 30-35 mmHg)during the surgery.IOP of both eyes(measured with a handheld tonometer),optic nerve sheath diameter(ONSD;measured at 3 mm behind the eyeball with bedside real-time ultrasound),circulatory and respiratory parameters of the patients were recorded before anesthesia(T0),immediately after anesthesia induction(T1),immediately after prone positioning(T2),at 2 h during operation(T3),immediately after supine positioning after surgery(T4)and 30 min after the operation(T5).Results Compared with those at T1,IOP and ONSD in both groups increased significantly at T3 and T4(P<0.05).IOP was significantly lower in hyperventilation group than in routine ventilation group at T3 and T4(P<0.05),and ONSD was significantly lower in hyperventilation group at T4(P<0.05).IOP was positively correlated with the length of operative time(r=0.779,P<0.001)and inversely with intraoperative etCO_(2)at T3(r=-0.248,P<0.001)and T4(r=-0.251,P<0.001).ONSD was correlated only with operation time(r=0.561,P<0.05)and not with IOP(r=0.178,P>0.05 at T3;r=0.165,P>0.05 at T4).Conclusion Small tidal volume hyperventilation can relieve the increase of IOP and ONSD during prone spinal surgery under general anesthesia.