Background and purpose: Following coronary artery bypass grafting (CABG) respiratory failure is inevitable, therefore, invasive ventilation is used in patients. This study was conducted to investigate the effect of airway pressure release ventilation (APRV) on arterial blood gas (ABG) of patients after CABG.

Materials and methods: This study was conducted in 32 patients in Mashhad Imam Reza Hospital, 2014. The patients were randomly divided into two groups (n= 16 per group). The two groups received synchronized intermittent mandatory ventilation (SIMV). Then the patients in group I were switched to APRV while in group II SIMV continued for another half an hour. Afterwards, group I received SIMV and group II received APRV for half an hour. In all three stages the values for ABG were recorded. Data was then analyzed in SPSS.

Results: The mean values of PaCO₂ showed no significant changes in three stages between the two groups (P>0.05) but the mean values of PaO₂ in APRV stage in first group (P< 0.001 and P< 0.01) and second group (P< 0.003 and P< 0.002) showed significant increases compared to that of the first and second SIMV mode.

Conclusion: APRV led to improvement of oxygenation.