Effects of β_2 agonist salbutamol aerosol on the uptake of sevoflurane in elderly patients with chronic obstructive pulmonary disease / 复旦学报（医学版）

ABSTRACT

Objective To investigate the effects of β_2 agonist salbutamol aerosol on the uptake of sevoflurane in elderly patients with chronic obstructive pulmonary disease (COPD). Methods A randomized, placebo-controlled and double-blinded trial was designed. Twenty-six patients were recruited and randomly allocated to salbutamol group (group E, n=13) and placebo group (group C, n=13). Eligible patients were elderly patients with ASA physical status Ⅱ-Ⅲ, a body mass index (BMI) between 18 and 30 kg/m~2, well-defined clinical diagnosis of COPD. Routine monitoring (consists of a three-lead ECG, pulse oximetry, noninvasive blood pressure and expired gas analysis) was instituted and 500 mL Ringer's lactate solution was administered. Bispectral index (BIS) monitoring was initiated prior to induction. All subjects were received inhaled aerosol 200 μg according to manufacturers' recommendations 30 minutes before induction of anesthesia. Controlled ventilation was applied after the trachea was intubated. When stable hemodynamics was maintained for 5 minutes, fresh gas flow was set to 2 L/min with 2% sevoflurane in admixture, then HR, invasive arterial blood pressure (IABP), SpO_2, P_(ET)CO_2, bispectral index (BIS), minimum alveolar concentration (MAC), concentrations of inhaled sevoflurane (F_I) and end-tidal (F_E) were recorded at 1, 2, 3, 4, 5, 7,10, and 15 minutes after inhalation of sevoflurne. The P_(peak) and P_(plat) were also measured in 1, 5, and 10 minutes after the successful endotracheal intubation. Results Compared to the placebo group, the F_E was significantly higher at 2, 3, 4, and 5 minutes in experiment group. Peak airway pressure and plateau pressure in experiment group were strikingly lower than control group (P<0.05). There was no statistical significance about BIS variations between these groups in respective time in spite of increased MAC (P>0.05). Conclusions The increasing rate of alveolar concentration of sevoflurane was accelerated after the administration of inhaled salbutamol aerosol (200 μg) 30 minutes before induction of anesthesia, it might increase the uptake of sevoflurane.