摘要
目的观察脊柱矫形术患者控制性降压时异氟醚对压力感受反射敏感性(BRS)的影响,探讨异氟醚控制性降压的机制。方法15例择期行脊柱侧凸矫形术的女性患者,年龄13～16岁, ASAⅠ或Ⅱ级。手术初期用硝酸甘油1μg·kg-1·min-1,速率逐渐升高,控制平均动脉压(MAP)55—65 mm Hg,当心率大于95次/min时,静脉注射艾司洛尔,使心率控制在90次/min以下,随后逐渐升高吸入异氟醚浓度至1.6%,降低硝酸甘油的输注速率直至停用硝酸甘油和艾司洛尔。分别于诱导前即刻、气管插管后即刻、平卧位呼气末异氟醚浓度0.7%时、俯卧位后即刻、呼气来异氟醚浓度1.3%时、停用硝酸甘油和艾司洛尔30 min、俯卧位呼气末异氟醚浓度0.7%时、平卧位后即刻测定BRS。结果当呼气末异氟醚浓度达到1.6%后(54±14)min停用硝酸甘油和艾司洛尔。随着异氟醚呼气末浓度的增加,BRS逐渐降低,停用硝酸甘油和艾司洛尔30 min时BRS最低(P<0.05或0.01)。结论异氟醚达到一定麻醉深度后抑制BRS,此作用是其控制性降压的机制之一。
Objective The purpose of this study was to investigate the effect of isoflurane on baroreflex sensitivity （BRS） during induced hypotension and to illucidate the mechanism of isoflurane-induced hypotension. Methods Fifteen female ASA Ⅰ or Ⅱ patients aged 13-16 yrs undergoing seoliosis surgery were studied. The patients were unpremedicated. Radial artery and internal jugular vein were cannulated for BP and CVP monitoring. ECG, BP and SpO2 were continuously monitored before and during anesthesia. Anesthesia was induced with midazolam 0.04 mg· kg^-1, fentanyl 2μg· kg^-1 and propefol 2 mg· kg^-1 . Tracheal intubation was facilitated with rocuronium 1 mg· kg^-1. Anesthesia was maintained with isoflurane inhalation and fentanyl infusion （0.4μg· kg^- 1· h^-1 ）. Nitroglycerin （NTG） was infused at 1 μg· kg^- 1 ·min^- 1 at the beginning of surgery to control MAP at 55-65 mm Hg and esmolol 20 mg was given i.v. to control HR 〈 90 bpm. Iseflurane concentration was then gradually increased to 1.6% （end-tidal concentration）. NTG infusion and esmolol bolus injection were then stopped. MAP was maintained at 55-65 mm Hg with isoflurane alone. BRS was measured according to Smyth H.S. et. al. Phenylephrine 50-100 μg was injected i.v. SP increased by 20-30 mm Hg. The R-R interval on ECG and SP were recorded within 5 min after phenylephrine injection. The linear regression analysis of the R-R intervals （ms） and the corresponding SP （mm Hg） was performed. The slope was BRS, if r^2 was 〉 0.8. BRS was measured before induction of anesthesia （T1 ）, immediately after intubation （T2）, when end-tidal concentration of isoflurane reached 0.7% （T3, supine） （T4, prone）, when end-tidal concentration of isoflurane reached 1.3% （T5 ）, at 30 min after NTG infusion and esmolal bolus injection were stopped （T6 ） when end-tidal concentration of isoflurane was decreased to 0.7% （prone, T7 ） and immediately after the patients were turned supine （T8 ）. Results When end-tidal isoflurane concentration reached 1.6%, the desired level of hypetension could be maintained without NTG infusion and esmolol injection. BRS gradually decreased with increasing end-tidal isoflurane concentration. BRS was the lowest at 30 min after termination of NTG infusion and esmolol bolus injection. Conclusion Isoflurane depresses BRS and BRS depression may be involved in the mechanism of isoflurane-induced hypotension.
出处
《中华麻醉学杂志》
CAS
CSCD
北大核心
2005年第8期569-571,共3页
Chinese Journal of Anesthesiology
