Prolonged mechanical ventilation after open heart surgery
The mortality of patients who require prolonged mechanical ventilation for respiratory distress after open heart surgery is high. It is still very difficult to predict accurately who will require this treatment and who will survive. Moreover, the reasons why postoperative respiratory distress develops are not always clear. This paper is concerned with a series of such patients. The results with particular reference to the patients’ cardiac status and to the mode of death are discussed.
Twenty-five consecutive patients who required prolonged mechanical ventilation after open heart surgery for congenital or acquired heart disease and who met two criteria were included in this retrospective study. The first criterion was that to justify the term “prolonged mechanical ventilation” the patient required not less than 3 days of ventilator therapy. The second criterion was that in each case there was obvious clinical evidence of the need for it. Many critically ill patients are ventilated for some days after cardiac surgery without any attempt at spontaneous breathing. Such patients were included in this series only if they also showed clear evidence of respiratory distress when mechanical ventilation was interrupted. The criterion used in this center for initiating mechanical ventilation for respiratory distress after cardiac surgery, for deciding when to attempt its discontinuance and for the weaning procedure has been described,1–3 and was used in these cases. Basically, this approach relies heavily on clinical signs and pays little or no attention to the blood-gas state, which is commonly not analyzed until ventilator therapy . . .