Maximizing Use of Continuous Positive Airway Pressure in Stroke Rehabilitation Patients With Obstructive Sleep Apnea
Phase: NA
Conditions: Sleep Apnea, Obstructive, Stroke, Patient Adherence
Sponsor: University of Washington

Official title: Maximizing Use of Continuous Positive Airway Pressure in Stroke Rehabilitation 
Patients With Obstructive Sleep Apnea 
 
NCT number: 02809430 
 
Document date: March 10, 2019 
  
 

Design: Single-arm, open-label study 
Objectives: To assess the effectiveness of a multifaceted and intensive adherence program on 3-
month CPAP adherence and measures of stroke outcome (NIH stroke scale and Functional 
Independence Measure) among stroke patients undergoing inpatient rehabilitation (IPR) 
Methods: 
Eligible stroke patients (Table I) were enrolled and trialed auto-adjusting CPAP (4–20 cm H2 O; 
Dream Station, Philips Respironics) over a 3-night run-in period during IPR. Devices were 
interrogated for nightly usage, average pressure, and a residual apnea-hypopnea index (the 
respiratory events per hour of sleep). At the end of the run-in period, evidence of OSA was 
determined based on airflow resistance detected by the machine (see diagnosis of OSA below). 
Patients with evidence of OSA were eligible for CPAP treatment during IPR and after discharge 
from IPR. Nurses, respiratory therapists, sleep technologists, and clinical psychologists initiated 
the SCOUTS intensive CPAP adherence protocol during IPR emphasizing early CPAP tolerance, 
individual motivation (Table II) and support throughout the treatment period. The primary end 
point was CPAP adherence over 90 days from CPAP initiation, defined as ≥4 hours of use on 
≥70% of days. Secondary efficacy end points were changes in the motor and cognitive 
components of the Functional Independence Measure (FIM) between admission and 3 to 4 
months after discharge from IPR and in the National Institutes of Health Stroke Scale (NIHSS) 
between enrollment 
and 90 days. 
 
Diagnosis of obstructive sleep apnea (OSA)  
 
To avoid delays inherent to administering formal sleep studies and interpreting results during 
inpatient stroke rehabilitation, we utilized device detected flow resistance. Study participants 
were started on an auto-adjusting CPAP machine (DreamStation, Philips Respironics) both to 
rapidly diagnose OSA and to provide earlier treatment.1, 2 After a 3-night run-in period during 
inpatient rehabilitation, auto-adjusting CPAP devices were interrogated for the mean pressure 
over the run-in period and the nightly residual apnea-hypopnea index, based on flow 
measurements (AHIFlow). The diagnosis of OSA was determined based on data from the CPAP 
device downloads using one of two criteria: 1) average airflow limitation over the entire run-in 
period, defined as mean CPAP pressure ≥ 5 cm H2O over a minimum of 3 hours of use, OR 2) 
on-treatment AHIFlow ≥ 5 events/hour on any of the 3 nights. Participants were excluded if the 
download showed evidence of central sleep apnea with a clear airway index ≥ 10 or of complex 
sleep apnea with an AHIFlow ≥ 25.  
 
SCOUTS Intensive CPAP Adherence Program (iCAP)  
To improve CPAP use, a SCOUTS iCAP was initiated during IPR and targeted 3 aspects of 
adherence: CPAP tolerance, motivation and support. To improve CPAP tolerance, rehabilitation 
nurses, respiratory therapists and sleep technologists led an iterative process of device 
adjustments, mask interface changes, OSA education and encouragement. To enhance 
motivation for CPAP use, patients watched a patient testimonial video on CPAP and stroke 

recovery and met with a clinical psychologist for motivational interviewing (MI) during IPR to 
discuss patients’ readiness to change, confidence in using CPAP and coping techniques to adjust 
to CPAP use (see Table II). The 30-minute face-to-face MI sessions occurred within one week of 
starting auto-adjusting CPAP. The MI session were focused on building motivation to use CPAP 
and alter the subject’s decisional balance about using CPAP as it relates to patient-specific goals. 
To improve support, the adherence program included nightly visits by respiratory therapists 
during IPR to improve self-efficacy with CPAP and tailored written feedback prior to discharge 
from the IPR unit detailing CPAP download data, adjustments made during IPR and goals and 
barriers for CPAP use. Phone calls were also made weekly for one month after discharge from 
the IPR unit to encourage CPAP use and troubleshoot any device or mask problems.  
Efficacy Measures  
The National Institutes of Health Stroke scale (NIHSS; range, 0 to 42; higher scores indicate 
greater neurologic impairment) scores were obtained in-person on enrollment and at 90 ± 7 days 
from enrollment. The Functional Independence measure (FIM) scores were obtained as part of 
routine clinical care. The FIM included a motor and cognitive component (motor range, 13-91; 
cognitive range, 5 to 35; lower scores indicate greater functional disability). The admission FIM 
scores were obtained in-person by rehabilitation nurses and therapists upon admission to the IPR 
unit and follow-up FIM scores were obtained as part of routine clinical care through phone 
interview by IT Health Track, Inc., between 3 and 4 months from IPR unit discharge (mean 106 
days); telephone response rates are approximately 60%.  
Statistical Analyses  
We compared baseline demographics, stroke severity and rehabilitation characteristics by 
adherence, using t-tests and Chi-squared tests as appropriate. To evaluate for predictors of 
adherence (Table III), we performed logistic regression, adjusting for baseline demographic 
covariates determined a priori including age (≥ 65 years), race/ethnicity (White versus non-
White or Hispanic), sex, obesity (body mass index ≥30 kg/m2),baseline NIHSS score ≥ 5 and 
inpatient rehabilitation length of stay (weeks). As those with aphasia were noted to be adherent 
to CPAP, we added this stroke characteristic into separate models post-hoc.  
We examined for differences in baseline, 3-month and changes between baseline and 3- months 
in NIHSS, motor FIM and cognitive FIM by CPAP adherence using the t-test with unequal 
variances (Table IV). We also evaluated for association of CPAP adherence with 3-month 
NIHSS and cognitive FIM change using linear regression in models adjusting for age ≥ 65 years, 
sex, race/ethnicity, body mass index ≥ 30, and baseline NIHSS score at study enrollment (Table 
IV). Finally, we evaluated the proportion of adherent and non-adherent participants who had 
improvement in the cognitive FIM and NIHSS, which was greater than the mean improvement 
among the entire sample: ≥ 7 for cognitive FIM improvement and ≥ 4 for NIHSS improvement 
(Table V).  
 
 

Table I. Main Selection Criteria  
Inclusion Criteria  
Informed consent 
 
Acute ischemic stroke or intraparenchymal hemorrhage  
 
Age ≥ 18 years  
 
Admission to inpatient stroke rehabilitation unit at Harborview Medical Center and the 
University of Washington Medical Center  
 
Exclusion Criteria  
 
Stroke related to bleeding disorder, substance abuse, tumor, vascular malformation, trauma or 
other secondary cause 
 
Active CPAP use at time of enrollment 
 
Advanced congestive heart failure (New York Heart Association class 3 or 4)  
 
Requiring supplemental oxygen or nasogastric feeding tube  
 
Participation in another research outcome study  
 
 

Table II. Motivational Interviewing Data Form  
Subject’s understanding of stroke and sleep apnea:  
 
Subject’s readiness to change:  
*Pre-contemplation  
*Contemplation  
*Preparation  
*Action  
*Maintenance  
 
Any small achievable subgoals: 
 * YES   
* NO 
 
Subject’s reason for using CPAP:  
*Stroke prevention  
*Stroke recovery  
*Sleep improvement  
*Other  
 
Subject’s reason for not using CPAP: 
  
*Claustrophobia 
 
*Anxiety 
 
*Sleep disturbance 
 
*Mask fit or leak problems  

 
*Device problems  
 
*Other 
 
On a scale of 1-10, how important do you think it is for you to treat sleep apnea and use the  
CPAP device?  
 
On a scale of 1-10, how confident are you in your ability to use the CPAP device from now until 
the next time we meet?  
 
 
 

Table III. Baseline factors associated with 3-month CPAP adherence, odds ratio (95% 
confidence interval)*  
*All models included age, sex, obesity and weeks on inpatient rehabilitation. Model 1 
additionally included race and baseline NIHSS ≥ 5; model 2 for race and aphasia; model 3 for 
race, aphasia and baseline NIHSS ≥ 5.  
 
Model 1  
Model 2  
Model 3  
White race  
10.9 (1.7, 701)  
3.7 (0.7, 19.8)  
8.2 (1.1, 62.3)  
Aphasia  
-----  
12.9 (1.3, 129)  
8.0 (0.7, 87.7)  
NIHSS≥5  
14.9 (1.9, 115.7)  
----  
10.6 (1.2, 92.6)  
 

Table IV. Improvement in cognitive FIM and NIHSS associated with CPAP adherence  
 
  
Adherent, mean (SD) 
Non-adherent, mean (SD) 
P-value* 
Baseline 3-months Change Baseline 3-months Change Unadjusted Adjusted 
 
Motor 
FIM† 
 
48.5 
(11.2) 
79.7 
(12.1) 
31.2 
(15.7) 
47.3 
(17.6) 
77.5 
(10.8) 
30.2 
(13.2) 
0.83 
0.65 
 
Cognitive 
FIM† 
 
24.1 
(6.9) 
32.4  
(3.7) 
8.2 
(6.5) 
28.5 
(3.9) 
33.1 
(2.4) 
4.6  
(3.0) 
0.03 
0.02 
 
NIHSS 
 ‡ 
 
6.5  
(4.3) 
2.7  
(3.1) 
-3.8 
(2.6) 
4.1  
(2.2) 
2.6  
(2.6) 
-1.6 
(2.2) 
0.003 
0.03 
 
CPAP indicates continuous positive airway pressure; SD, standard deviation; NIHSS, National 
Institutes of Health Stroke Scale; Cognitive FIM, cognitive component of Functional 
Independence measure 
 
* Difference between mean changes in outcome between adherent and non-adherent patients: 
unadjusted using t-test with unequal variances and adjusted for age, sex, body mass index, race 
and baseline NIHSS using linear regression  
 
† n=22 adherent group and n=12 non-adherent 
‡ n=30 adherent group and n=19 non-adherent  
 
 

Table V. Improvement in cognitive FIM and NIHSS associated with CPAP adherence  
Patient characteristics 
Adherent 
Non-adherent 
P-value 
Cognitive FIM improvement ³ 
7, n (%)* 
10 (45) 
3 (25) 
0.24 
NIHSS improvement ³ 4, n 
(%)† 
16 (53) 
3 (16) 
0.01 
 
* n=22 adherent group and n=12 non-adherent  
† n=30 adherent group and n=19 non-adherent 
 
 
 
  
 
 

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