Brazilian Journal of Anesthesiology
https://bjan-sba.org/article/doi/10.1590/S0034-70942003000400003
Brazilian Journal of Anesthesiology
Scientific Article

Comparação entre ventilação controlada a volume e a pressão no tratamento da hipoxemia no período pós-operatório de cirurgia de revascularização do miocárdio

Comparison between pressure controlled and controlled mandatory ventilation in the treatment of postoperative hypoxemia after myocardial revascularization

Fábio Bonini Castellana; Luiz Marcelo Sá Malbouisson; Maria José Carvalho Carmona; Célia Regina Lopes; José Otávio Costa Auler Júnior

http://dx.doi.org/10.1590/S0034-70942003000400003 Braz J Anesthesiol, vol.53, n4, p.440-448, 2003
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Resumo

JUSTIFICATIVA E OBJETIVOS: Ventilação controlada à pressão tem sido utilizada como modalidade ventilatória de eleição em pacientes que desenvolvem hipoxemia importante no período pós-operatório de cirurgia de revascularização do miocárdio. Contudo não existem estudos mostrando que a ventilação controlada à pressão é mais efetiva na reversão da hipoxemia pós-operatória que ventilação controlada a volume. O objetivo deste estudo foi comparar os efeitos de ventilação controlada à pressão e ventilação controlada a volume sobre a oxigenação sistêmica em pacientes que desenvolvem hipoxemia caracterizada por uma relação PaO2/FiO2 menor que 200 no período pós-operatório imediato de cirurgia cardíaca. MÉTODO: Sessenta e um pacientes com relação PaO2/FiO2 menor que 200 foram alocados em um grupo submetido à ventilação controlada a pressão e outro a volume. O volume corrente, a freqüência respiratória, a relação inspiração/ expiração e a pressão positiva ao final da expiração foram as mesmas no dois grupos. Após a admissão na UTI e após períodos de 1 ou 2 horas de ventilação mecânica, a relação PaO2/FiO2 e o shunt pulmonar foram quantificados. RESULTADOS: Houve um aumento significativo na relação PaO2/FiO2 e uma diminuição significativa no shunt pulmonar após 1 ou 2 horas de ventilação mecânica; contudo não foram observadas diferenças entre as modalidades ventilatórias. CONCLUSÕES: As modalidades ventilatórias controladas a volume e pressão foram igualmente eficientes no tratamento da hipoxemia observada em pacientes no pós-operatório imediato de cirurgia de revascularização do miocárdio, mostrando que o padrão de administração do fluxo inspiratório é pouco relevante para o tratamento da hipoxemia pós-operatória.

Palavras-chave

CIRURGIA, CIRURGIA, COMPLICAÇÕES, VENTILAÇÃO

Abstract

BACKGROUND AND OBJECTIVES: 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.

Keywords

COMPLICATIONS, SURGERY, SURGERY, VENTILATION

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