The Journal of Thoracic and Cardiovascular Surgery, Vol 90, 287-290, Copyright © 1985 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
The effect of ventilation on systemic blood gases in the presence of left ventricular ejection during cardiopulmonary bypass
RA Moore, JD Gallagher, BP Kingsley, G Lemole, D Kerns and DL Clark
The effect of pulmonary ventilation upon systemic arterial blood gases
during cardiopulmonary bypass in the presence of left ventricular ejection
was evaluated in 20 adult male patients undergoing coronary artery bypass
grafting. Following rewarming, establishment of a sinus rhythm, and
production of a pulse pressure of at least 20 mm Hg on the arterial
pressure trace caused by left ventricular ejection, arterial blood gases
were obtained from the arterial and venous extracorporeal circuits and the
radial arterial cannula. Patients were then randomly assigned to a
nonventilation (n = 10) or a ventilation (n = 10) group. The ventilation
group was given 10 breaths/min with 100% oxygen at a tidal volume of 10
ml/kg. Whereas the nonventilation group received apneic oxygenation at zero
end-expiratory pressure. After 5 minutes the arterial blood gas data were
again obtained. Significant findings (p less than 0.05) included decreases
in systemic carbon dioxide tension and increases in systemic pH in the
ventilation group and decreases in systemic oxygen tension in the
nonventilation group. Although the changes in the arterial blood gases were
significant, these changes occurred well within the limits of clinical
acceptability. It is concluded that left ventricular ejection for short
periods during full cardiopulmonary bypass does not necessitate pulmonary
ventilation.
