Effects of two methods of preoxygenation on mean arterial pressure, cardiac output, peak airway pressure, and postsuctioning hypoxemia.

Abstract

Our purpose was to determine which method of preoxygenation (ventilator versus manual resuscitation bag [MRB]) produced minimal changes in mean arterial pressure (MAP), cardiac output (CO), and peak airway pressure and prevented postsuctioning hypoxemia in patients after coronary artery bypass graft surgery. Three lung inflation breaths at F10(2) 1.0 were delivered at 12 and 14 cc/kg of lean body weight via ventilator or MRB, followed by 10 seconds of continuous endotracheal suctioning. This sequence was repeated three times. The MRB produced a greater (12 mm Hg) increase in MAP than the ventilator (9 mm Hg), which was not statistically significant (p less than 0.09). MRB caused a larger increase to CO than the ventilator, but this was not statistically significant (p less than 0.10). The MRB generated significantly (p less than 0.000) higher mean airway pressures (45 mm Hg) than the ventilator (23 mm Hg); the larger the volume the higher the pressure. Both methods effectively prevented postsuctioning hypoxemia; the larger the volume the higher the PaO2.