Spontaneous ventilation with laryngeal mask airway for general anesthesia in patients undergoing radical mastectory

Objective To investigate the effects of laryngeal mask anesthesia(LMA) for general anesthesia on the respiration and hemodynamics functions in patients undergoing radical mastectory.Methods Forty patients of American Society of Anesthesiologists(ASA) status Ⅰ or Ⅱ,who were scheduled for elective radical mastectory under general anesthesia,were randomly allocated to either spontaneous ventilation group(SV group) or intermittent positive pressure ventilation group(IPPV group).Spontaneous respiration was maintained in SV group;the laryngeal mask was intubated when the lower jaw was relaxed;mechanical ventilation was given till simultaneous respiration recovered.IPPV group received routine anesthesia induction and anesthesia maintenance.The systolic and diastolic blood pressure(SBP and DBP),heart rate(HR),pulse oxygen saturation(SpO2),minute volume of ventialtion(VE),end-expired CO2 tension(PETCO2),inspiratory concentration of sevoflurane(CINSEV),and expiratory concentration of sevoflurane(CETSEV) were recorded at different time points.The blood samples were taken from each group for blood gas analysis.Results ① Satisfactory intubation conditions were obtained in both groups.The time of induction was significantly longer(P0.01)and the CETSEV before intubation in SV group was significantly higher than those in the IPPV group(P0.01).Both groups had different degrees of respiration inhibition.The period of awareness and the incidence of agitation were similar between the two groups(both P0.05).② SBP,DBP,SpO2 and HR were similar between the two groups(all P0.05).The VE at T1,T2 was significantly lower than at T0 in SV group(both P0.05);PETCO2 at T2 was significantly higher than at T0(P0.01).The PETCO2 at T1,T2 in SV group were significantly higher than those in IPPV group(P0.05 or 0.01).③ The blood gas analysis in each group had normal results in both groups.PH at T6 was significantly lower than that at T0(P0.05、0.01).The(PaCO2) at T6 in IPPV group was significantly higher than at T0(P0.05).Conclusion Spontaneous ventilation with LMA for general anesthesia in patients undergoing radical mastectory can help to maintain the hemodynamics and respiratory function at normal range,which may substitute mechanical ventilation.