Effect of CPAP Therapy on Mild OSA Measured by the Epworth Sleepiness Scale Betsy A. Vosnock Department of Biological Sciences, York College of Pennsylvania ABSTRACT Obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) are associated with excessive daytime somnolence (EDS). Both diseases can be effectively treated with continuous positive airway pressure (CPAP). However, most studies to date concentrate on patients with moderate to severe OSA. The objective of this study was to document the effectiveness of CPAP therapy in patients with mild OSA/UARS by measuring EDS before and after treatment with CPAP therapy. Twenty-five patients with a respiratory disturbance index (RDI) of less than twenty as documented by a diagnostic nocturnal polysomnography (NPSG) were selected and treated with CPAP. Patients completed an Epworth Sleepiness Scale (ESS) prior to treatment and after their follow up office visit with their physician. The ESS decreased post treatment with CPAP. This study concluded that EDS in patients with mild OSA/UARS decreased after wearing CPAP therapy as measured by the ESS. CPAP was an effective treatment for mild OSA/UARS. INTRODUCTION Epworth Sleepiness Scale How likely are you to doze off or fall asleep in the following situations? 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing Situation: Sitting and reading Watching TV Sitting inactive in a public place (e.g. a theater or meeting) As a passenger in a car for an hour without a break Lying down to rest in the afternoon when circumstances permit Sitting and talking to someone Sitting quietly after a lunch without alcohol LITERATURE CITED Ballester, E., Badia, J.R., Hernandez, L., Carrasco, E. de Pablo, J., Fornas, C., Rodriguez-Roisin, R. and Montserrat, J.M. 199 Evidence of the effectiveness of continuous positive airway pressure in the treatment of sleep apnea/hypopnea syndrome. American Journal of Respiratory and Critical Care Medicine 159: Gottlieb, D.J., Whitney, C.W., Bonekat, W.H., Iber, C., James, G.D., Lebowitz, M., Nieto, F.J. and Rosenberg, C.E Relationship of sleepiness to respiratory disturbance index: the sleep heart study. American Journal of Respiratory and Critical Care Medicine 159: Gottlieb, D.J., Yao, Q., Redline, S., Ali, T. and Mahowald, M.W Does snoring predict sleepiness independently of apnea and hypopnea frequency. American Journal of Respiratory and Critical Care Medicine 162: Kryger, M.H., Roth, T., and Dement, W.C Principles and practice of sleep medicine. 1st ed. W.B. Saunders Company, Philadelphia, Pa. Montserrat, J.M., Ferrer, M., Hernandez, L., Farre, R., Vilagut, G., Navajas, D., Badia, J.R., Carrasco, E., de Pablo, J. and Ballester, E Effectiveness of CPAP treatment in daytime function in sleep apnea syndrome. American Journal of Respiratory and Critical Care Medicine 164: Phillipson, E Sleep apnea-a major public health problem. The New England Journal of Medicine 328: Strohl, K.P. and Redline, S Recognition of obstructive sleep apnea. American Journal of Respiratory and Critical Care Medicine 154: ACKNOWLEDGEMENTS Yaroslav Lando, M.D., Department of Pulmonary Medicine, Lancaster General Hospital Karl W. Kleiner, Ph.D., Assistant Professor of Biology More than 100 million Americans fail to get a good night’s sleep and experience excessive daytime somnolence (EDS). There are over eighty-four sleep disorders that result in a diminished quality of life and health, and endanger public safety through sleep-related accidents. The Department of Transportation estimates that 200,000 reported automobile accidents each year may be sleep- related and twenty one percent of all drivers have fallen asleep behind the wheel at least once (Phillipson 1993). These sleep-related accidents may be the result of the two most common types of sleep disorders, obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) or snoring. OSA and UARS occur when the muscles of the soft palate and uvula relax, obstructing the airway. When the pressure to breath increases, muscles of the diaphragm and chest work harder resulting in momentary awakenings or arousals from sleep. These brief awakenings are not generally remembered but may happen hundreds of times each night resulting in EDS. Warning signs of sleep apnea include loud snoring, falling asleep at inappropriate times such as at work or while driving, lack of concentration, forgetfulness, irritability, anxiousness, or depression. OSA is associated with a low level of blood oxygen, high blood pressure and irregular heart beats (Strohl and Redline 1996). Continuous positive airway pressure (CPAP) is 98% corrective for OSA and UARS (Ballester et al. 1999). Many studies have been performed evaluating the effectiveness of CPAP treatment in daytime function in patients with OSA. However, they neglect patients with mild OSA/UARS. A study that documents the effectiveness of CPAP therapy in patients with mild OSA and measures EDS would bridge the gaps in the knowledge of patients with this category of OSA. EDS is subjectively measured by the Epworth Sleepiness Scale (ESS) (Gottlieb 2000). HYPOTHESIS The null hypothesis is that there is no difference in the effectiveness of CPAP therapy on patients with mild OSA/UARS as measured by the Epworth Sleepiness Scale. METHODS RESULTS CONCLUSIONS CRITERIA 25 patients were studied with a respiratory disturbance index (RDI) of less than 20 as documented by an in laboratory diagnostic nocturnal polysomnography (NPSG) at Lancaster General Hospital Sleep Disorders Center, an AASM accredited sleep center in Lancaster, Pa. RDI was the number of apneas and hypopneas divided by the number of minutes of sleep. A total RDI factored in the number of snoring events and represented the true number of momentary awakenings that disrupted sleep. EXPERIMENT A standard twenty one channel polygraph was recorded at 10 mm/sec via Nihon-Kohden polysomnograph machine for both the diagnostic and therapeutic NPSG. NPSG data was scored in accordance with the criteria set forth by Rechtschaffen and Kales (Kryger 1989). Therapeutic NPSG with CPAP titration was started at 5 cm H2O and titrated by 1 cm H20 until all apneas, hypopneas and snoring were eliminated. CPAP pressure was prescribed and used for at least thirty consecutive nights for six to eight hours per night. An Epworth Sleepiness Scale (ESS) was completed prior to the therapeutic NPSG and after the thirty day trial period. ESS is a popular self-completion sleep scale in which patients rate on a scale of zero to three the likelihood that they would fall asleep in eight common situations. A score of zero indicates no EDS whereas a score of twenty-four exhibits the maximum degree of EDS. A score of nine indicates pathological sleepiness. Figure 2. Mean + s.e. (N=25) respiratory disturbance index (RDI = number of apneas and hypopneas/minutes of sleep) with and without snoring pre and post treatment with CPAP therapy. Asterisks indicate an extremely significant difference between RDI’s with and without snoring pre treatment and post treatment with CPAP from a paired t-test (p < ). Pre and post therapy ESS scores and RDI with and without snoring were collected and compared using the t-test function in INSTAT. 1.CPAP was found to be an effective treatment for mild OSA/UARS. 2.RDI (with and without the snoring) decreased in patients with mild OSA/UARS post treatment with CPAP duplicating the results of Montserrat et al. (2001) and Ballester et al. (1999). Montserrat et al. (2001) and Ballester et al. (1999) examined patients with moderate to severe OSA. Therefore, despite skepticism from the health insurance industry, CPAP as treatment for mild OSA/UARS was beneficial. 3.EDS as measured by the ESS decreased after wearing CPAP therapy as in the Sleep Heart Health Study conducted by Gottlieb et al. (1999). The Sleep Heart Health Study suggested that ESS correlated with the RDI. In other words, as RDI decreased, the ESS decreased. Figure 2. Mean + s.e. (N=25) Epworth Sleepiness Scale(ESS) pre and post treatment with CPAP. Asterisks indicate a significant difference between ESS from a paired t- test (p value=0.0156).