七氟醚或丙泊酚对允许性高碳酸血症改善控制性降压肩关节镜手术患者脑氧饱和度作用的影响

Effect of sevoflurane or propofol on cerebral oxygen saturation in patients with permissive hypercapnia undergoing con⁃trolled hypotension and arthroscopic shoulder surgery

目的通过实时监测控制性降压肩关节镜手术患者术中脑氧饱和度(cerebral oxygen saturation,rSO_(2))的变化,探讨七氟醚与丙泊酚对允许性高碳酸血症改善rSO_(2)作用的影响。方法选择择期行肩关节镜手术患者52例,ASA分级Ⅰ、Ⅱ级,年龄18~65岁,按随机数字表法分为两组(每组26例):七氟醚组(S组)与丙泊酚组(P组)。所有患者均采用相同的诱导方案,诱导后测定rSO_(2)基础值,术中S组用七氟醚维持麻醉,P组用丙泊酚维持麻醉,行控制性降压,调整通气策略逐渐升高P_(ET)CO_(2),并分别于30~35 mmHg(1 mmHg=0.133 kPa)、35~40 mmHg、40~45 mmHg、45~50 mmHg、50~55 mmHg水平稳定5 min后记录MAP、心率、BIS及rSO_(2)等数值。于术前1 d、术后第1天、术后第3天行简易精神状态检查(Mini-Mental State Examination,MMSE)量表调查,记录其评分及术后并发症发生情况。结果与rSO_(2)基础值比较,两组患者在控制性降压后rSO_(2)水平明显下降(P<0.05);与P_(ET)CO_(2)为30~35 mmHg阶段比较,维持P_(ET)CO_(2)于35~40 mmHg、40~45 mmHg、45~50 mmHg、50~55 mmHg阶段的rSO_(2)明显升高(P<0.05);S组较P组rSO_(2)随P_(ET)CO_(2)水平上升的趋势更显著,P_(ET)CO_(2)为50~55 mmHg时rSO_(2)水平S组较P组高(P<0.05),且S组P_(ET)CO_(2)为50~55 mmHg时与P_(ET)CO_(2)为30~35 mmHg时rSO_(2)数值的差值高于P组(P<0.05);与基础值测定阶段的MAP比较,两组患者P_(ET)CO_(2)为30~35 mmHg时MAP均明显下降(P<0.05);两组患者在P_(ET)CO_(2)各维持阶段下的MAP、心率及BIS差异无统计学意义(P>0.05)。两组患者各时点MMSE评分及术后恶心呕吐发生情况差异无统计学意义(P>0.05)。结论肩关节镜术中,丙泊酚或七氟醚麻醉维持时,允许性高碳酸血症均可有效改善控制性降压引起的rSO_(2)水平下降,相比丙泊酚,应用七氟醚维持麻醉时允许性高碳酸血症改善rSO_(2)的作用更为明显,但两种麻醉药物对术后认知功能的影响仍有待进一步考证。

Objective To discuss the effect of sevoflurane and propofol on cerebral oxygen saturation(rSO_(2))in patients with permissive hypercapnia through observing the real‑time changes of rSO_(2)in patients undergoing shoulder arthroscopic surgery and con‑trolled hypotension.Methods A total of 52 patients who were scheduled for shoulder arthroscopic surgery,American Society of Anes‑thesiologists(ASA)gradesⅠ‒Ⅱ,aged 18‒65 years,were enrolled.According to the random number table method,they were divided in‑to two groups(n=26):a sevoflurane group(group S)and a propofol group(group P).All patients underwent the same induction protocol,before determination of the basic value of rSO_(2).During surgery,sevoflurane or propofol was used for anesthesia induction for group S and group P,respectively.After controlled hypotension,we adjusted ventilation strategy to gradually increase the partial pressure of end‑tidal carbon dioxide(P_(ET)CO_(2)),and recorded the values of mean arterial pressure(MAP),heart rate,bispectral index(BIS)and rSO_(2)after P_(ET)CO_(2)reached 30‒35 mmHg(1 mmHg=0.133 kPa),35‒40 mmHg,40‒45 mmHg,45‒50 mmHg and 50‒55 mmHg and stabilized for 5 min.The Mini‑Mental State Examination(MMSE)questionnaire was conducted one day before operation,and the first day and third day after operation.The score of questionnaire and incidence of postoperative nausea and vomiting were recorded.Results Com‑pared with the basic value of rSO_(2),rSO_(2)in the two groups significantly decreased after controlled hypotension(P<0.05).Compared with the stage of 30‒35 mmHg of P_(ET)CO_(2),rSO_(2)in the stage of 35‒40 mmHg,40‒45 mmHg,45‒50 mmHg and 50‒55 mmHg of P_(ET)CO_(2)signif‑icantly increased(P<0.05).The rising trend of rSO_(2)along P_(ET)CO_(2)levels was more obvious in group S than that in group P.When P_(ET)CO_(2)was 50‒55 mmHg,rSO_(2)in group S was higher than that in group P(P<0.05).The difference of rSO_(2)between 50‒55 mmHg and 30‒35 mmHg in group S was higher than that in group P(P<0.05).Compared with MAP at baseline,MAP significantly decreased when P_(ET)CO_(2)was 30‒35 mmHg in the two groups.There was no significant difference in MAP,heart rate and BIS values between the two groups at various levels of P_(ET)CO_(2)(P<0.05).There was no significant difference in MMSE score and incidence of postoperative nausea and vomiting between the two groups(P<0.05).Conclusions When propofol or sevoflurane is used for anesthesia maintenance dur‑ing shoulder arthroscopic surgery,permissive hypercapnia can effectively improve the decrease of rSO_(2)caused by controlled hypoten‑sion.However,compared with propofol,permissive hypercapnia can improve rSO_(2)more significantly during anesthesia maintenance with sevoflurane.The effect of these two anesthetics on postoperative cognitive function remains to be further studied.