The changes of respiratory mechanics during sevoflurance anesthesia induction in children with laryngeal papillomatosis

Abstract

Objective To observe the changes of respiratory mechanics with anemometer during sevoflurane inhalational anesthesia induction in children with laryngeal papillomatosis and in normal children, and to obtain the objective quantization parameter of predicting difficult ventilation/intubation and the effect of anesthesia deepened by controlled ventilation. Methods Twenty dyspneic children with laryngeal papillomatosis (L group) and 20 normal children (C group) were included in this study. General anesthesia was induced with intravenous ketamine 1 mg/kg and inhalation of oxygen 2 L/min +7% sevoflurane. The respiratory mechanics parameters were measured with an anemometer at four time points of anesthesia induction: T1, 1 min after intravenous ketamine,T2, initiation of sevoflurane inhalation,T3, 3 min after sevoflurane inhalation,T4, 2 min after controlled ventilation. Results The mean velocities [(1.48±0.20) m/s and(1.26±0.18) m/s], maximum velocities[(1.72±0.25) m/s and(1.97±0.31) m/s] of both inspiratory and expiratory airflows at T1 were higher in group L compared with group C (P 0.05). At T3 and T4, the ratios of mean inspiratory velocity to maximum inspiratory velocity were smaller in in group L (0.612±0.030 and 0.613±0.032) than in group C(P 0.05). Conclusion During sevoflurane inhalational anesthesia induction in children with laryngeal papillomatosis, hypoventilation is compensated by increased work of breathing. With anesthesia being deepened,upper airway obstruction is becoming more serious. It has not obvious effect that anesthesia induction was deepened with inhalational sevoflurane by controlled ventilation. Key words: Anemometer; Laryngeal papillomatosis; Sevoflurane; Anesthesia induction; Respiratory mechanics