间歇正压及呼气末正压通气对人体眼内压的影响

目的：探讨机械通气对人体眼内压（IOP）的影响,以避免不适当的机械通气对眼的损伤。方法：选择ASAI-II级择期手术患者10例。术前无中枢、心、肺、肝、肾疾患及眼外伤、青光眼等眼部疾病史。采用阻滞麻醉加健忘镇痛气管内插管法。术中间断静注γ-OH维持睡眠。以Drager SA-2型麻醉机行间歇正压通气（IPPV）或不同压力值的呼气末正压通气（PEEP,5cmH2O及10cmH2O）。分别于通气前、通气20min及撤机20min记录监测指标。结果：3种不同通气条件下,中心静脉压（CVP）及IOP在上机20min均比基础值上升（P〈0.01）。IPPV时,IOP从（1.7±0.2）kPa升至（2.0±0.3）kPa,PEEP为5cmH2O及10cmH2O时,IOP分别从（1.8±0.2）kPa升至（2.5±0.2）kPa和（1.9±0.2）kPa升至（2.9±0.3）kPa。3种通气方式间亦有显著差异（P〈0.01）。全部指标在撤机20min时均恢复至基础水平（P〉0.05）。CVP与IOP之间有很好的相关性（R=0.61,P〈0.01）。结论：严重眼外伤,内眼手术要求术后避免高眼压者和青光眼者若需机械通气,最好选用IPPV,必须用PEEP时,呼气末正压勿大于10cmH2O,通气中应监测IOP,避免严重并发症的发生。

Effects of intermittent positive pressure ventilation and positive end-expiratory pressure on intraocular pressure

Objective：To investigate the effects of intermittent positive pressure ventilation （IPPV） and positive end-expiratory pressure （PEEP） on intraocular pressure （IOP）. Methods： Ten patients without evidence of ocular disease were studied. Epidural block anesthesia combined with endotracheal intubation and intraoperative γ-OH sedation was performed in all patients. They were ventilated with IPPV and PEEP（5 cmH2O and 10 cmH2O）. The BP, PETCO2, CVP and IOP were measured simultaneously before ventilation, 20 min after start of ventilation and 20 min after ventilation. Results：IOP increased significantly from （1.7±0.2） kPa to （2.0±0.3） kPa in IPPV（P〈0.01）, and from （1.8±0.2） kPa to （2.5±0.2） kPa in 5 cmH2O PEEP （P〈0.01）, while from （1.9±0.2） kPa to （2.9±0.3） kPa during 10 cmH2O PEEP （P〈0.01）. CVP also increased significantly （P〈0.01） in parallel with IOP under the three modes of ventilation. Conclusion：IOP can remain normal range during IPPV or minimum PEEP, higher PEEP can produce a significant rise of IOP and may be dangerous.