Effect of chronic anemia on duration of non-hypoxic apnea during tracheal intubation after induction of general anesthesia in female patients

Abstract

Objective To evaluate the effect of chronic anemia on duration of non-hypoxic apnea during tracheal intubation after induction of general anesthesia in female patients.Methods Seventy-five ASA physical status Ⅰ or Ⅱ patients,aged 20-40 yr,of Mallampati class Ⅰ or Ⅱ,with body mass index ＜ 25 kg/m2,were enrolled in the study.According to the test results of hemoglobin (Hb),the patients were allocated into 3 groups (n =25 each):Hb ＞ 110 g/L group (group A),Hb 90-110 g/L group (group B),and 70 g/L ＜ Hb ＜ 90 g/L group (group C).Each patient inhaled 100％ oxygen through a mask with oxygen flow of 8 L/min and 3 min later anesthesia was induced with general anesthesia.Assisted ventilation was not performed during induction.After tracheal intubation,artificial ventilation was performed with pure oxygen when SpO2 decreased to 90％.The time from beginning of apnea to SpO2 of 90％ (duration of non-hypoxic apnea),and the minimum SpO2 and the maximum PET CO2 during the period of observation were recorded.Immediately before oxygen inhalation via a mask,immediately after beginning of apnea,and at the time for SpO2 decreasing to 90％,arterial blood samples were taken from 10 patients randomly chosen from each group for blood gas analysis.Results Compared with group A,the duration of non-hypoxic apnea was significantly shortened,and no significant change was found in the minimum SpO2 in B and C groups,and the maximum PET CO2 and PaCO2 while SpO2 decreasing to 90％ were decreased in group C.Compared with group B,the duration of non-hypoxic apnea was signifi.cantly shortened,PaCO2 while SpO2 decreasing to 90％ was decreased,and no significant change was found in the minimum SpO2 and the maximum PET CO2 in group C.Conclusion Mild and moderate chronic anemia shortens the duration of non-hypoxic apnoea to about 6.0 and 3.5 min,respectively,during tracheal intubation after induction of general anesthesia in female patients. Key words: Anemia; Anesthesia, general ; Intubafion, intratracheal ; Non-hypoxic apnoea