[abstract] THE USE OF PRESSURE-CONTROL VENTILATION TO MECHANICALLY VENTILATE CRITICALLY ILL ADULT AND PEDIATRIC PATIENTS

Abstract

BACKGROUND: Presently, there is no industry standard addressing mechanical ventilation within the multiplace chamber. In preparing to treat critically ill patients, we found very limited information on mechanical ventilator use in Class-A Hyperbaric Chambers. Most HBO2 programs use volume-control mechanical ventilation which requires constant manipulation during HBO2 treatments.. We hypothesized the physical characteristics of pressure-control ventilation would readily compensate for the changes in atmospheric pressure during treatments. MATERIALS AND METHODS: The Servo 900C (Maquet, Inc.) ventilator was modified for use in the chamber by the Biomedical Engineering Dept. A dual Siemens test lung was used to simulate the human lung. The ventilator was set in pressure control mode, respiratory rate (RR) of 12 breaths per minute, distending pressure of 22 cm H20 and inspiratory time of 1.0 sec. to deliver an expired tidal volume of 1.0L at sea level. Data was collected continuously at five test conditions: 1) sea level; 2) during descent; 3) 3 ATA; 4) 6 ATA; 5) during ascent. All data was collected from the electronic ventilator unit and mean values (+ SD) calculated. Patients were connected to the ventilator prior to compression and remained on the ventilator throughout the entire treatment. RESULTS: RR and exhaled tidal volumes remained unchanged during the 5-test conditions. No adjustments to the ventilator settings were required at any time during any of the treatments. To date, 9 patients (7 Adults, 2 Pediatric) have been successfully ventilated for over 25 treatments using the pressure-control mode for ventilation in our hyperbaric chamber. No untoward events were associated with mechanical ventilation during the treatments. CONCLUSIONS: Pressure-control ventilation is our standard for mechanically ventilating patients undergoing hyperbaric oxygen treatments.