Effects of inhalation of different concentrations of nitrous oxide on intracuff pressure of the laryngeal mask airway in patients during general anesthesia
10.3760/cma.j.issn.0254-1416.2009.04.005
- VernacularTitle:吸入不同浓度氧化亚氮对全麻患者双腔喉罩囊内压的影响
- Author:
Zhenhua QU
;
Jun WANG
- Publication Type:Journal Article
- Keywords:
Nitrous oxide;
Anesthesia,general;
Laryngeal masks
- From:
Chinese Journal of Anesthesiology
2009;29(4):305-307
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effects of inhalation of different concentrations of nitrous oxide on intracuff pressure (ICP) of the laryngeal mask airway (LMA) in patients during general anesthesia. Methods Forty-right ASA Ⅰ or Ⅱ patients aged 25-64 yr undergoing elective operations under general anesthesia were randomly divided into 4 groups (n=12 each): group C (100 %O2, group N2 (65 % O2 + 35%N2O), group N2 (50%O2 + 50 % N2O), and group N3 (35%O2 + 65%N2O). A suitable model of the LMA was selected according to height and weight. Anesthesia was induced with Ⅳ propofol 1.5-2.0 mg/kg, fentanyl 2-3 μg/kg, lidocaine 1-2 mg/kg and vecuronium 0.08-0.1 mg/kg and maintained with intravenous infusion of propofol and intermittent boluses of fentanyl and vecuronium. After the successful placement of LMA, the air was injected into the cuff to make intracuff pressure (ICP) reach 40 cm H2O (baseline). The ICP were recorded at 15, 30, 45, 60, 75 and 90 min (T1-6) following inhalation of N2O. Results The ICP grandually increased with the increase in the concentration of N2O (P<0.05). The ICP decreased at T2-6 in group C, but increased at T2-6 in group N1 and at T1-6 in group N2,3 as compared with baseline(P<0.05). There was a positive correlation between the ICP and inhalation time in group N1-3(r1-3=0.968,0.987,0.973 respectively, P<0.05). Conclusion The inhalation of N2O can increase the ICP in concentration- and time-dependent manners,
