The Effect of Chronic Anemia on Safety Period of Tracheal Intubation in Gynecology Patients

Every individual receiving a general anesthetic is at potential risk for developing a ''cannot intubate-cannot ventilate'' situation following anesthetic induction. Building up of oxygen reserves assumes great significance as this provides a longer duration of non-hypoxic apnea should one be faced with an unanticipated difficult airway. The main physiological functions of red blood cell hemoglobin are to deliver oxygen to the peripheral tissues. During anemia, a reduction in blood oxygen content occurs as a result of reduced Hb while arterial oxygenation and oxyhemoglobin saturation remain high. Previous studies about the duration of non-hypoxic apnoea focus on methods to improve the safety period of tracheal intubation. To our knowledge, there is no literature about the duration of non-hypoxic apnoea of anemia patients. The aim of this study was to assess the effect of chronic anemia on the duration of non-hypoxic apnoea during induction of anaesthesia.

After breathing for 3 minutes, anesthesia induction was conducted. The endotracheal tube position was confirmed after anesthesia induction. Patients were left apneic with the endotracheal tube open to room air. The non-hypoxic apneic period was recorded as the time (in seconds) taken for the drop in pulse saturation to 90% or an apneic period of 10 min elapsed, whichever was earlier.

Inclusion Criteria: patients scheduled to undergo general anesthesia American Society of Anesthesiologists Performance Status 1-2 adults Exclusion Criteria: Individuals with significant cardiorespiratory or cerebrovascular disease, difficult intubation history of epilepsy body mass index >25 kg/m2, and those who had smoking history in past 6 months