Performance of patients with Obstructive Sleep Apnoea (OSA) on a steering simulation after six months treatment with Nasal Continuous Positive Airway Pressure (NCPAP)

Journal article

The long-term effect of nCPAP on steering performance in OSA has not been assessed. 42 OSA patients (Epworth Sleepiness Score (ESS) ≥ 10, and ≥ 10/hr >4% SaO2 dips) performed three simulator drives each lasting for 30 minutes, and maintenance of wakefulness tests (MWT) at baseline, 1 month and 6 months. Patients were randomised to receive either sub-therapeutic or real nCPAP (Lancet 1999, 352:2100). Patients were retitrated at 1 month to therapeutic nCPAP. Performance was quantified by the standard deviation of steering error across the drive (sd), and reaction time (reactn) to identification of a target digit. Results are median, significance by Wilcoxon test. Median Sub-therapeutic (n = 23) Therapeutic (n = 19) 5/95 MONTH P P MONTH P P centile 0 1 6 0/1 1/6 0 1 6 0/1 1/6 Steer 0.36 0.42 0.23 NS 0.003 0.44 0.20 0.19 0.004 NS Error 0.15 0.14 0.14 0.15 0.13 0.08 (sd) /1.4 /1.2 /0.8 /1.2 /0.7 /0.5 Reactn 2.8 3.2 2.5 NS 0.04 2.7 2.1 2.2 0.001 NS /sec 1.4 1.7 1.3 1.7 1.5 1.2 /5.3 /3.9 /3.6 /5.3 /3.4 /3.2 MWT 20.1 25.7 37.6 NS 0.002 19.5 38.3 40.0 0.001 0.02 /min 7.7 7.1/ 9.5 6.8 15 29 /40 40 /40 /35 /40 /40. Therapeutic NCPAP significantly improves simulated steering performance in OSA. Despite improvement at 6 months the steering performance did not return to that of a group of controls (sd 0.16(0.13/0.31), although reaction time and sleepiness measurements were normal. This differential outcome suggests factors other than sleepiness may contribute to the impaired steering simulation performance in OSA, which persists after treatment.

Authors: Hack, M; Choi, S; Mullins, R; Dow, S; Davies, R

• Journal: Thorax
• Volume: 54
• Issue: SUPPL. 3
• Publication date: 1999-12-01
• ISSN: 0040-6376
• Language: English