Superior effect of dexmedetomidine used for induction of general anesthesia: prolonging duration of non-hypoxic apnoea

Objective To evaluate the effect of dexmedetomidine on the duration of non-hypoxic apnoea when used for induction of general anesthesia. Methods Eighty female patients, aged 18-64 yr, with body mass index of 18.5-24.9 kg/m2, of American Society of Anesthesiology physical status Ⅰ or Ⅱ, with Mallampati grade Ⅰ or Ⅱ, scheduled for elective surgery with general anesthesia requiring tracheal intubation, were divided into 2 groups (n=40 each) by a random number table method: dexmedetomidine group (group D) and conventional group (group C). Dexmedetomidine 0.5 μg/kg was intravenously infused over 10 min in group D, and the normal saline 40 ml was intravenously infused in group C. In two groups, pure oxygen 8 L/min was inhaled via the closed mask, 3 min later fentanyl 3 μg/kg, etomidate 0.3 mg/kg and rocuronium 0.6 mg/kg were intravenously injected in turn, assisted ventilation was not performed in this period.The anesthesia machine was immediately connected to perform mechanical ventilation when SpO2 was reduced to 92% after tracheal intubation.Arterial blood samples were collected for blood gas analysis, and PaO2 was recorded at the time of entering the operation room, immediately before inhaling pure oxygen, at the beginning of injecting fentanyl, and when SpO2 was decreased to 92%.The development of adverse cardiovascular events during the trial, and duration of non-hypoxic apnoea were recorded. Results Compared with group C, the incidence of adverse cardiovascular events was significantly decreased, and the duration of non-hypoxic apnoea was prolonged, and no significant change was found in PaO2 at the time of entering the operation room, immediately before inhaling pure oxygen, at the beginning of injecting fentanyl, and when SpO2 was decreased to 92% in group D (P<0.05). Conclusion Dexmedetomidine can prolong the duration of non-hypoxic apnoea and raise the safety of endotracheal intubation during general anesthesia induction when used for induction of general anesthesia. Key words: Dexmedetomidine; Anesthesia, general; Duration of non-hypoxic apnoea