ADEQUACY OF PRESCRIBING POSITIVE AIRWAY PRESSURE THERAPY BY MASK FOR SLEEP-APNEA ON THE BASIS OF A PARTIAL-NIGHT TRIAL

We tested the hypothesis that a prescription for positive-pressure the rapy (including pressure level, patient-device interface, and positive -pressure modality, e.g., CPAP or BiPAP(TM)) for obstructive sleep apn ea (OSA) can be developed on the same night as the polysomnographic (P SG) diagnosis is made. Fifty consecutive patients with OSA in whom a p artial-night PSG diagnosis was made (PSG(D)) underwent a therapeutic t rial of positive-pressure therapy during the remainder of the night (P SG-PP(P)). The average apnea index during PSG(D) was 54.96 +/- 36.3 (m ean +/- SD). On a subsequent full-night PSG (PSG-PP(F)), the prescript ion was tested. Thirty-one of the 50 patients were satisfactorily trea ted with CPAP, without variation of the interface during both PSG-PP(P ) and PSG-PP(F). In these patients the average pressure prescription w hile receiving PSG-PP(F) was statistically higher than during PSG-PP(P ) (11.77 +/- 3.6 versus 10.56 +/- 3.6 cm H2O, respectively, p = 0.002) . In 14 of these 31 patients (45%) some alteration in pressure require ment was necessary during PSG-PP(F). Eleven patients required 2.5 cm H 2O higher pressure and three patients required 5 cm H2O higher pressur e during PSG-PPF than during PSG-PP(P). There was a change of interfac e across the two therapeutic trials in 15 patients. Although the avera ge pressure required by the 10 of these patients who continued to rece ive CPAP (i.e., did not require a change to BiPAP) was statistically t he same across both trials (13 +/- 3.5 versus 14 +/- 2.9 cm H2O, PSG-P P(P) and PSG-PP(F), respectively, p = 0.22), six of them required 2.5 cm H2O more pressure, and one required 5 cm H2O less pressure during t he full-night trial. This distribution of pressure changes appeared si milar to that observed in patients who maintained the same interface d uring both PSG tests. Eight patients required a change in positive-pre ssure modality across the two trials. Of these, seven changed from CPA P to BiPAP during PSG-PP(F). We conclude that although a majority of p atients with OSA can obtain a satisfactory prescription for positive-p ressure therapy on the same night as the diagnosis is made, a substant ial proportion of them will require alterations of that prescription, including changes in pressure, patient-device interface, or positive-p ressure modality.