A home-made IMV-CPAP system for difficult to wean patients.

A continuous, high flow gas was incorporated into the conventional intermittent mandatory ventilation (IMV) circuit attached to the pressure or volume cycled ventilator which had no built-in IMV mode. These created a continuous flow IMV-CPAP system. During the spontaneous breathing period, the gas flow was high enough to raise a 5-6 cm H2O CPAP level and cause minimal airway pressure fluctuation, an indicator of reduced breathing work. Sixteen patients who were unable to tolerate T-piece weaning were weaned successfully by this IMV-CPAP system. They were medical and surgical patients with prolonged ventilatory support (10-62 days). The respiratory mechanics prior to weaning were relatively marginal. Tidal volume, minute volume and respiratory rate were 260.71 +/- 104 cc, 9.71 +/- 3.54 LPM and 30.29 +/- 5.31/minute respectively. During the weaning course arterial pCO2 retained gradually to their steady states in chronic CO2 retaining patients. This resulted in very minimal fluctuations in arterial pH. All patients were weaned successfully with the average weaning duration of 14.19 days.