[Comparison between pressure controlled and controlled mandatory ventilation in the treatment of postoperative hypoxemia after myocardial revascularization].
OBJECTIVE
Pressure controlled ventilation (PCV) has been used as the ventilation mode of choice in coronary artery bypass graft surgery patients who develop severe hypoxemia in the immediate postoperative period. However, there are no evidences showing that pressure controlled ventilation is more effective in reversing postoperative hypoxemia than controlled mandatory ventilation (CMV). This study aimed at comparing the effects of both ventilation modes on systemic oxygenation in cardiac surgery patients who develop hypoxemia characterized by PaO2/FiO2 ratio lower than 200 in the immediate postoperative period.


METHODS
Participated in this study 61 consecutive patients with PaO2/FiO2 ratio lower than 200 who were randomly allocated in two groups according to the ventilatory mode (CMV and PCV). Tidal volume, respiratory rate, inspiration/expiration ratio and positive end-expiratory pressure were kept constant throughout the study in both groups. PaO2/FiO2 ratio and pulmonary shunt were obtained 1 or 2 hours after ICU admission.


RESULTS
A significant increase in PaO2/FiO2 ratio and a decrease in pulmonary shunt were observed in both groups one or two hours after mechanical ventilation. However, no differences were observed between both ventilatory modes.


CONCLUSIONS
Both ventilatory modes were equally effective in reversing hypoxemia observed in the immediate cardiac surgery postoperative period. Results show that inspiratory flow patterns are not relevant in the treatment of post cardiac surgery hypoxemia.
Castellana
Fábio Bonini
FB
Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil.
Malbouisson
Luiz Marcelo Sá
LM
Carmona
Maria José Carvalho
MJ
Lopes
Célia Regina
CR
Auler Júnior
José Otávio Costa
JO