Weaning from short-term mechanical ventilation.

sor, associate dean for research, and director, Center for Nursing Research, University of Texas, School of Nursing, at Houston. Hemodynamic Stability Patients’ responses to both mechanical and spontaneous ventilation vary according to myocardial function and reserve capacity. Cardiac failure, which may not be apparent when a patient is receiving mechanical ventilation, can be exacerbated with transition to spontaneous ventilation. Signs of hemodynamic instability include an acute or gradual decrease in arterial blood pressure, tachycardia, bradycardia, dysrhythmias, weak peripheral pulses, decreased pulse pressure, acute or gradual increase in pulmonary capillary wedge pressure, decreased cardiac output, and decreased mixed venous oxygen saturation. Hemodynamic stability is difficult to evaluate when a patient is receiving vasoactive support, a common situation after cardiac surgery. Therefore, during weaning, hemodynamic parameters should be monitored closely in such patients.