Is (re)titration of nasal continuous positive airway pressure for obstructive sleep apnoea necessary?

To assess changes in nasal continuous positive airway pressure (nCPAP) pressure requirements across time in obstructive sleep apnoea (OSA), and whether routine retitrations are indicated.

Most sleep laboratories perform one nCPAP titration, although some authors have found changes in pressures with time. A cohort of patients with OSA in a randomised controlled trial of nCPAP provided us with data on changes in titration pressures with time.

One hundred and one patients with symptomatic OSA (Epworth Sleepiness Scale > or =10, and >10 episodes/h of >4% dips in SaO(2) overnight) were recruited to a 1 month trial comparing real (autotitrated) and placebo nCPAP. At 1 month all patients were titrated and received real nCPAP thereafter. Eighty five were retitrated at about 6 months.

Average pressures did not change between the initial value and 1 month (95th centile, 8.47 (SD 3.00), 8.94 (2.85) cm H(2)O), although there were large individual changes (mean difference, +0.47, SD 2.30, range -5 to +6 cm H(2)O). There was a small fall at 6 months (mean difference -0.68, SD 2.60, range -6 to +6 cm H(2)O, P<0.03) with no suggestion that the changes from 1-6 months were clinically important.

This study suggests that routine nCPAP retitrations are not necessary. In conjunction with other published data, the night to night variation we found implies that a nCPAP calibration using an algorithm (based on obesity and OSA severity) might be as clinically successful as conventional one night titrations. However, further studies will be needed to specifically confirm this hypothesis.