BACKGROUND: High-frequency jet ventilaion is considered a reliable technique for anesthesia and critical care including respiratory failure but there are adverse reactions such as carbon dioxide retension and dry of respiratory mucosa. The purpose of this study was to confirm the effects of combined high- frequency jet ventilation (HFJV) and converntional mechanical ventilation (CMV) on the cardiovascular system, arterial blood gases tension and mean airway pressure in 9 Korea mongrel dogs with pulmonary edema induced by oleic acid. METHODS: During CMV with 20 breaths/minute, 10 ml/kg of tidal volume and F1O2 1.0, parameers were evaluated (base line value). When pulmonary edema was developed, HFJV was applied initially with 120 breaths/minute, inspiratory time 30% and driving pressure 40 psi F1O2 1.0 for 60 minutes (control value) and thereafter simultaneous use of CMV was applied with the tidal volume of 10 ml/kg and each respiratory rate 8, 4, 2, 1, 0.5 per minute for 30 minutes. RESULTS: Combined application of HFJV and CMV (above repiratory rate 1 per minute) achieved the improvement of oxygenation and carbon dioxide elimination, and Paw was decreased without undesirable effects on cardiovascular system in case of the induced pulmonary edema. CONCUSIONS: From above results we recommanded that HFJV combined with CMV may be a useful method of treatment for respiratory failure.