To evaluate the effectiveness of mechanical ventilation and a number of complications in respiratory depression patients cawsed by elapidea snake bite, study has conducted on 66 patients, bitten by bungarus multicintus snake, treatmented on poison control center at Bach Mai Hospital in Hanoi with two methods of mechanical ventilation: high Vt (12-15 ml/kg) and average Vt (10 ml/kg) combinating with 5 cm H2O PEEP, obtained the following ,results: - The average duration of ventilation: 9.8 + or - 7.1 days. - 2 ventilation methods are effective in improving blood oxygen and effects of treatment and prevention atelectasis, however ventilation with' high Vt (12-15 ml/kg) atelectasis better reserve than Vt 10 ml/kg + 5 cm H20 PEEP.- Complications of pneumonia is mainly related to mechanical ventilation (54.5 percent). - The most common etiologic agent of pneumonia is A.baumannii (45 percent), followed by P.aeruginosa, K.pneumonia, S.aureus and Candida albicans are 25 percent occupancy rate, common in patients with long-term ventilation ( 10 days).