[Comparison between flexible laryngeal mask airway and reinforced tracheal tube used for lumbar vertebral surgery in prone position].

OBJECTIVE: To estimate the safety and feasibility of flexible laryngeal mask airway (FLMA) for lumbar vertebral surgery in prone position.

METHODS: In the study, 120 adult patients scheduled for lumbar vertebral surgery under intravenous general anesthesia were divided into group FLMA and reinforced tracheal tube (RTT) group at random. Heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded at the beginning of anesthesia induction (T0) and on the time of artificial airway intubation (T1), 1 min after intubation (T2), extubation (T3), 1 min after extubation (T4) as well. The number and time required for intubation were recorded. Peak airway pressure (PPEAK ), airway sealing pressure (PAS ) in group FLMA and fiberoptic bronchoscopy scale (FBS) were recorded after artificial airway intubation, turned over into prone position and after the operation started, as well as on the time of 1 hour after the operation started, 2 hours after operation started and when the operation stopped. Finally, respiratory complications after extubation, including hypoxemia, laryngospasm, coughing, vomiting, hoarseness, and pharyngalgia, were observed and whether there was blood or sewage inside and outside the artificial airway was recorded.

RESULTS: There was no difference in the number and time required for intubation between the two groups (P>0.05). There was no difference in PPEAK and FBS between the two groups, and also the same at the different time points in each group (P>0.05). PAS in group FLMA was the same at the diverse time points during anesthesia (P>0.05) and always higher than PPEAK in the perioperative period. In group FLMA, there was no difference in HR, SBP and DBP between the time points of T2 and T1, also of T4 and T3 (P>0.05). In group RTT, HR, SBP and DBP were significantly higher between the time points of T2 and T1 (P<0.01); SBP was significantly higher between the time points of T4 and T3 (P<0.01), DBP and HR were higher between the time points of T4 and T3 (P<0.05). SBP in group FLMA was significantly lower than in group RTT at T2 (P<0.01), HR and DBP were lower than those in group RTT simultaneously (P<0.05). On the time point of T4, SBP, DBP and HR in group FLMA were lower than those in group RTT (P<0.05). The incidence of coughing and pharyngalgia after extubation was significantly lower in group FLMA than in group RTT (P<0.01), with the incidence of hoarseness was lower in group FLMA than in group RTT (P<0.05). There was no difference in the incidence of hypoxemia, vomiting and blood seen outside the cuff between the two groups (P>0.05) while no laryngospasm and sewage seen outside the artificial airway in each group.

CONCLUSION: For suitable patients, FLMA can be used in mechanical ventilation forlumbar vertebral surgery in prone position with more stable circulation and less respiratory complications than RTT. Further clinical validation is needed for the safety of FLMA.