Forty-four patients were studied for a mean of 14 months (range, 8 to 39 months) after beginning the treatment. Data on the use of CPAP are detailed in Table 1. At the end of the study, 41 patients still used their apparatus every night, and the apparatus was used all night by 36 patients. At this time the quantitative study of the mean length of time that the apparatus was used, determined with a time counter, gave an average of 6.02 ± 2.48 h per night, compared to 7 ± 1.65 h based on the patients’ estimates of use. Thirty of the 44 initial patients (68 percent) fell within the compliant group, characterized by use of the apparatus every night throughout the night, with a time counter measurement of over 5 h per night on the average. Side effects related to treatment by nocturnal ventilation with CPAP (Table 2) were mainly cutaneous erosion of the bridge of the nose, which occurred in 52 percent (23) of the treated patients. Other side effects were rhinitis, leakage, or intolerance of the materials constituting the mask. Some disadvantages encountered were directly related to the apparatus, such as noise, which was 46 dB HL measured at 1 m from the apparatus. The noise was judged to be annoying in 20 percent (9) of the cases. Ten patients had to have separate rooms, and four patients had to have their apparatus changed due to the noise. The apparatus was found to limit the freedom of patients in 20 percent (9) of the cases and represented a professional disturbance for 23 percent (10) of the patients. Eleven patients changed their apparatus during the course of treatment: 8 due to noise and the other 3 due to the size and weight of the mask. One patient ended the treatment after 2 months of use due to substantial rhinorrhea with persistent nasal obstruction, despite local treatment of symptoms. canadianfamilypharmacy
Compliance was studied as a function of the year of use. Compliance remained stable in 1989, 1990, and 1991 (5 h 25 min, 5 h 23 min, and 5 h 26 min, respectively). The correlation between the objective average length of time that the apparatus was used (counter reading) and morphometric and pulmonary function tests is not significant.
A significant reduction was found in the AH I (p = 0.001) and a marked improvement was seen in the percentage of slow-wave sleep (p = 0.001) and rapid-eye-movement (REM) sleep (p = 0.03) during nasal CPAP (Table 3). Similarly, analysis of hypersomnia scores (Fig 1 and Table 3) confirms a significant reduction (p = 0.001) in diurnal sleepiness according to the change in the hypersomnia score from 3.84 ± 1.59 to 1.7 ± 1.5 between the initial consultation before treatment and the testing at the end of the study.
The correlation between the average length of time that the apparatus was used and the initial polysomnographic recording parameters was significant for (1) the AHI (p = 0.013; r = 0.37), (2) the proportion of light sleep (p = 0.045; r = 0.30), and (3) slow-wave sleep (p = 0.037, r = -0.31). A significant correlation was also found between the daily use of nasal CPAP and (1) the difference in the AHI (p = 0.025; r = – 0.34), (2) the difference in mean oxygen saturation during sleep (p = 0.013; r = 0.38), and (3) the difference in hypersomnia scores (p = 0.006; r = – 0.40) obtained before and after treatment. There was no significant correlation between the daily use and the sex of the patient or the type of mask.
Table 1—Use of CPAP
|Patient||Estimated Use per Night, h||Counter Data, h per Nightf||No. of Nights per Week||AllNightLongt||Group§|
Table 2—Side Effects of CPAP
|Side Effect||CompliantGroup(n = 30)||Noncompliant Group (n = 14)|
|Noise||5 (17)||3 (21)|
|Bulk||3 (10)||4 (29)|
|Heaviness||2 (7)||4 (29)|
|Cutaneous erosion||16 (53)||7 (50)|
|Rhinitis||3 (10)||3 (21)|
|Limited autonomy||7 (23)||4 (29)|
|Professional disturbance||5 (17)||5 (36)|
Table 3—Characteristics of Patients
|Data||AHI||Sa02, %||Sleep Stage, %||SleepinessScore|
|Mean During Night||Awake||Lowest During Night||LightSleep||Slow-waveSleep||REMSleep|
|Before treatment||51.9 ± 26.6||86.7 ± 5.7||93.4 ± 2.7||66.2 ± 17.1||71.9 ± 14.5||13.5 ± 12.5||13.9 ± 9.6||3.84 ± 1.59|
|With treatment||6.23 ± 26.8||91.4 ± 4.8||93.5 ± 2.4||84.6 ± 7.9||60.3 ± 15.2||20.6 ± 10.4||18.3 ± 10.7||1.70 ± 1.50|
|Difference||45.6 ± 26.9||4.7 ± 5.6||0.1 ± 2.08||18.4 ± 17.8||11.6 ± 17.2||7.1 ± 9.7||4.4 ± 10.9||2.13 ± 1.83|
Figure 1. Evolution of hypersomnia scores under nasal CPAP. Hypersomnia score corresponds to number of “yes” answers for six questions concerning daytime sleepiness: (1) tired in the morning, after getting up; (2) lapse of attention while reading book or watching television; (3) falling asleep under any circumstances; (4) lapse of memory; (5) fighting sleep during day; and (6) nap after lunch. Therefore, the greater the sleepiness, the greater the hypersomnia score. Note shift of hypersomnia score to lowest values with nasal CPAP Full bar indicates score with treatment, and shaded bar indicates initial treatment score.