Objective To investigate the effect of different sputum suction methods on the incidences of pulmonary infections in patients with mechanical ventilation.Methods Four hundred and sixty-six patients with mechanical ventilation were randomly divided into study group(n=219)and control group(n=247).The two groups were treated with continued balloon filling and airway humidification.Besides,the control group received conventional open sputum suction and the study group closed continuous negative pressure sputum suction.The two groups were compared in terms of incidence of pulmonary infections.Result The incidence of the study group(8.2%)was significantly lower than that of the control group(14.6%)(χ2=4.58,P<0.05).Conclusion Compared with the traditional open conventional sputum suction method,closed continuous negative pressure sputum suction may be more effective in reducing the incidence of pulmonary infection in patients with mechanical ventilation.