TRANSDIAPHRAGMATIC PRESSURE IN QUADRIPLEGIC INDIVIDUALS VENTILATED BYDIAPHRAGMATIC PACEMAKER

Background - Electrophrenic pacing can be used in the management of ve ntilatory failure in quadriplegic patients. A study was undertaken to determine the pattern of transdiaphragmatic pressure (PDI) during the conditioning phase of electrophrenic pacing to see if it had a possibl e role in optimising the process of conditioning. Methods - The tidal volume (TV) and PDI were measured in a group of six quadriplegic patie nts commencing ventilation by low frequency pulse stimulation (7-10 Hz ) and low respiratory rate stimulation (<10 breaths/min). Results - Ti dal volume increased between baseline and month 1 (4.33 ml/kg, p<0.001 ) and between months 1 and 2 (3.00 ml/kg, p<0 05) and then stabilised. PDI was higher during bilateral diaphragmatic pacing (mean (SD) 1.73 (0.30) kPa) than with either left (1.15 (0.34) kPa) or right (0.86 (0. 37) kPa) unilateral pacing. PDI varied throughout the observation peri od, probably by interaction between recovery of the diaphragmatic fibr es and the pacing regimen. Conclusions - Patients with quadriplegia du e to high spinal injury can be maintained with ventilation by continuo us electrophrenic pacing. The control criteria used in this study for pacing were tidal volume and the patient's tolerance, and the PDI meas urement did not contribute any additional information to help with man aging the conditioning process.