Reproducibility of a standardized titration procedure for the initiation of continuous positive airway pressure therapy in patients with obstructive sleep apnoea

Background: Manual titration of continuous positive airway pressure (CPAP) under polysomnographic control is the method most commonly employed to esta blish the minimal effective pressure (P-eff) for the treatment of the obstr uctive sleep apnoea syndrome (OSA). To date, however, the reproducibility o f P-eff titrated in this way has not been investigated in any detail. Objec tives: The present study aims to establish the reproducibility of P-eff det ermined by manual titrations of CPAP under polysomnographic control in the sleep lab. Methods: In a group of 50 patients (5 women), with a mean (SD) a pnoea-hypopnoea index of 39.3 (21.8), apnoea index of 28.1 (20.9) and oxyge n desaturation index of 39.3 (22.6), with newly diagnosed OSA, manual titra tion of CPAP was performed on two consecutive nights using the following st andard titration protocol: starting at 4 mbar, CPAP was increased by steps of 1 mbar at intervals of at least 5 min, until no signs of airway obstruct ion could be seen, and arousals were no longer elicited. When no airway obs truction was detected over a period of 30 min, the pressure was lowered onc e during the night in steps of 1 mbar at intervals of at least 10 min, unti l obstructive events reappeared, whereupon the pressure was again increased as described above, until, once more, no signs of airway obstruction and n o arousals occurred. The second titration was carried out in a blind manner , that is the lab technician did not know the results of the first pressure titration. Results: The mean (SD) P-eff for all titrations was 8.1 mbar (2 .9). A high level of correlation was found between the P-eff titrated on th e first night and that titrated on the second night (Spearman correlation c oefficient = 0.89). In a few individual cases, however, differences of up t o 3 mbar were found between P-eff on the first night and P-eff on the secon d night. On average, the P-eff measured on the second night was 0.5 mbar (S D = 1.3, range: -2.0 to 3.0 mbar) higher than that of the first night. Conc lusions: With standardization of the manual titration of CPAP, P-eff is rea dily reproducible. In individual cases, however, a difference of as much as 3.0 mbar between the two titrations is possible. Copyright (C) 2001 S. Kar ger AG, Basel.