An investigation of the validity of the Lifeshirt in comparison to standard polysomnography in the detection of obstructive sleep apnea.

BACKGROUND: Due to the cost and waiting times for traditional sleep studies, there is great interest in finding alternatives for the diagnosis of sleep apnea. Several alternatives exist, including ambulatory devices. Our laboratory utilized one such device, a form-fitting vest called the Lifeshirt, and compared its accuracy to that of polysomnography (PSG). METHODS: PSG was performed with simultaneous utilization of the Lifeshirt on 50 individuals who met screening criteria for obstructive sleep apnea. Participants came to the sleep laboratory approximately 2 h before their normal bedtime. A sleep technician prepared each participant for PSG and Lifeshirt monitoring. "Lights Out" occurred when the participant was ready for bed, and time in bed was standardized to approximately 7 h. PSGs were scored by experienced personnel in our laboratory, while Lifeshirt data were sent electronically to the Lifeshirt manufacturer for analysis. The major variable that was compared between PSG and Lifeshirt was the apnea hypopnea index (AHI), or the number of apneas and hypopneas per hour. Due to incomplete data on two participants, analyses were completed on 48 individuals. RESULTS: Sensitivity of the Lifeshirt ranged from .85 (AHI of > or =5) to 1.00 (AHI of > or =25). Specificity ranged from .67 to 1.00. Using the Bland-Altman technique of determining agreement, the mean difference between the AHI of the Lifeshirt and PSG was 1.02 (+/-16.36). When these values are plotted, every case falls within the limits of agreement, with one exception. CONCLUSIONS: The Lifeshirt compared favorably with PSG and could be used with considerable confidence for the screening of patients with suspected obstructive sleep apnea.

Occurrence of nighttime gastroesophageal reflux in disturbed and normal sleepers.

BACKGROUND & AIMS: It is not uncommon in a sleep laboratory to encounter individuals who have complaints of disturbed sleep, but who do not meet the criteria for a sleep disorder when evaluated by polysomnography. Because gastroesophageal reflux is known to occur in many individuals without their awareness, it is possible that some of these individuals might be suffering from reflux that is disturbing their sleep. METHODS: Eighty-one individuals with complaints of disturbed or unrefreshing sleep, but no complaints of heartburn, were recruited. A comparison group of 39 individuals with neither sleep nor heartburn complaints also was studied. Both groups were studied on 2 separate occasions by simultaneous polysomnography and pH monitoring to detect the presence of nighttime gastroesophageal reflux and to determine sleep outcomes. RESULTS: In the disturbed-sleep group 27% of subjects had at least one reflux event compared with 33% in the normals. In the subjects who experienced reflux, the disturbed-sleep group had a significantly greater percentage of acid exposure time compared with the normals (9.5% vs 1.6%; P < .05). Participants in the disturbed-sleep group also had a longer sleep-onset latency (P < .05) and less total sleep time (P < .05) compared with the normal sleepers. CONCLUSIONS: Among individuals with complaints of disturbed sleep, there was a subset of individuals who had significant gastroesophageal reflux. We speculate that sleep-related gastroesophageal reflux may play a role in producing disturbed sleep in individuals without heartburn and otherwise unexplained sleep disturbance.

Associations between subjective night sweats and sleep study findings.

BACKGROUND: In 2 previous studies, patients reporting night sweats were found to be more likely to have other sleep-related symptoms. Sleep apnea is often mentioned as a possible cause of night sweats, but there is little evidence to support this assertion. METHODS: Retrospective review of data from 2 sleep laboratories in Oklahoma City, Oklahoma. Analyses included bivariate and multivariate tests of associations between reported night sweats and other sleep-related symptoms, scores on specific sleep inventories, and findings from polysomnography. RESULTS: Patients who reported night sweats were more likely to report daytime fatigue (P = .001); creepy/crawly feelings in their legs (P = .003); kicking during sleep (P = .004); snoring (P = .03); nighttime breathing trouble (P < .0001); awakening in the night with aches and pains (P < .0001); and waking in the morning with a headache (P = .0002) and still tired (P = .002) as compared with those who did not report night sweats. They also had higher mean scores on the Epworth Sleepiness Scale (P < .0001). However, there was no statistically significant association between reported night sweats and sleep onset latency, arousal index, apnea hypopnea index, periodic leg movement index, or total sleep time. CONCLUSIONS: Subjective night sweats are associated with a variety of other sleep-related symptoms, but we could find no evidence for an association between subjective night sweats and objective evidence of specific sleep disorders.

Acidic and non-acidic reflux during sleep under conditions of powerful acid suppression.

BACKGROUND: During sleep, individuals are uniquely vulnerable to acid reflux. Acid reflux during sleep has been studied by a number of investigators, but non-acid reflux is largely unexplored. METHODS: In this study, 15 individuals with significant subjective complaints of heartburn were treated with esomeprazole, 40 mg bid, and with placebo, in random order, for 1 week each. After 1 week of treatment, participants underwent combined impedence/pH monitoring and polysomnography. In both drug and placebo conditions, these procedures were done after participants consumed a meal designed to increase the likelihood of reflux events. RESULTS: Total reflux events and acid reflux events were significantly decreased with proton-pump inhibitor (PPI) treatment as compared to placebo. Nonacid reflux events were more common with PPI treatment as compared to placebo, but this result was not statistically significant. The ratio of non-acidic to acidic events was significantly greater with PPI treatment, however. Similar results were found for reflux events that occurred only during sleep. Proximal migration of acidic vs non-acidic reflux events was found to be similar. There was no difference in sleep architecture between placebo and drug conditions. CONCLUSION: PPI treatment reduced overall reflux events, but non-acidic reflux events were relatively more likely to occur with PPI treatment. The occurrence of these non-acidic reflux events on PPI might conceivably explain why some individuals continue to have symptoms after PPI treatment.

The effect of 1 week of continuous positive airway pressure treatment in obstructive sleep apnea patients with concomitant gastroesophageal reflux.

STUDY OBJECTIVES: Patients with obstructive sleep apnea (OSA) have a very high incidence of gastroesophageal reflux (GER). Previous studies have shown that the use of continuous positive airway pressure (CPAP) reduces the frequency of reflux events, but these studies only assessed the effect of a single night of treatment. The aim of this study was to assess the effect of 1 week of CPAP treatment on reflux in patients with OSA and GER. DESIGN: Sixteen patients with OSA and GER were recruited. Polysomnography followed by 24-h, continuous esophageal pH monitoring were performed at baseline. Patients with an apnea-hypopnea index (AHI) > 20/h and 24-h acid contact time (ACT) of at least 6% were included. As part of the polysomnography-qualifying evaluation, all patients underwent CPAP titration to reduce the AHI to < 10/h. Patients were then sent home receiving nasal CPAP for 1 week; after 1 week, esophageal pH monitoring was repeated while receiving CPAP. MEASUREMENTS AND RESULTS: The AHI fell from 63.3 +/- 38.5 to 3.2 +/- 2.2/h (mean +/- SD) [p < 0.001]. Total ACT fell from 13.9 +/- 11.6 to 5.6 +/- 2.7% (p < 0.001). The upright ACT was reduced from 12.4 +/- 6.8 to 6.8 +/- 3.8% (p = 0.01), and the supine (during the sleeping interval) ACT was reduced from 16.3 +/- 18.8 to 3.8 +/- 7.6% (p < 0.01). Eighty-one percent of the patients had a reduction in supine ACT to within the normal range (< 4%). CONCLUSIONS: In OSA patients with significant heartburn complaints, CPAP would appear to be an efficacious approach to the treatment of both disorders.