Autonomic tone in medical intensive care patients receiving mechanical ventilation and during a CPAP weaning trial.

Mechanical ventilator support and the resumption of spontaneous ventilation or weaning create significant alterations in alveolar and intrathoracic pressure that influence thoracic blood volume and flow. Compensatory autonomic tone alterations occur to ensure adequate tissue oxygen delivery, but autonomic responses may produce cardiovascular dysfunction with subsequent weaning failure. The authors describe autonomic responses of critically ill patients (n = 43) during a 24-hr period of mechanical ventilatory support and during the 24 hr that included their initial spontaneous breathing trial using continuous positive airway pressure.

Prevalence of myocardial ischemia during mechanical ventilation and weaning and its effects on weaning success.

Background: Myocardial ischemia may be considered both a consequence of weaning from ventilation and a potential cause of weaning failure. A limited number of investigations have evaluated myocardial ischemia during mechanical ventilation and weaning and its effect on weaning success. The purpose of this pilot investigation was to determine the prevalence of myocardial ischemia in a diverse group of medical intensive care unit (MICU) patients during baseline mechanical ventilation, during weaning using continuous positive airway pressure, and up to 24 hours after extubation and to evaluate the relationship between ischemia and weaning failure.

Hemodynamic changes during discontinuation of mechanical ventilation in medical intensive care unit patients.

Background: Cardiac dysfunction can prevent successful discontinuation of mechanical ventilation. Critically ill patients may have undetected cardiac disease, and cardiac dysfunction can be produced or exacerbated by underlying pathophysiology.

Objective: To describe and compare hemodynamic function and cardiac rhythm during baseline mechanical ventilation with function and rhythm during a trial of continuous positive airway pressure in medical intensive care patients.

The relationship between dermal pressure ulcers, oxygenation and perfusion in mechanically ventilated patients.

Background: More than 1.5 million hospitalized patients develop dermal pressure ulcers (DPUs) annually, which increases cost and prolongs length of stay. Mechanically ventilated patients may be at a high risk for DPU development, but research has not focused on the prevalence of dermal pressure ulcers in this population or the factors associated with dermal pressure ulcer development.