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Impact of continuous positive airway pressure (CPAP) on chronic cough in obstructive sleep apnoea (OSA) – A randomized controlled trial
Abstracts / Sleep Medicine 14S (2013) e93–e164
http://dx.doi.org/10.1016/j.sleep.2013.11.200
e95
3
Department of Respiratory Medicine, King’s College Hospital, Australia Department of Thoracic Medicine, Concord Repatriation General Hospital, University of Sydney, Australia 4
Mechanism of sudden cardiac death in obstructive sleep apnea, revisited A. Chan 1, N. Antonio 2 1 Chanwell Clinic Institute for Heart & Sleep Disorders, Stanford University School of Medicine (1993–2012), United States 2 Chanwell Clinic Institute for Heart & Sleep Disorders, United States
Introduction: Obstructive sleep apnea (OSA) raises the risk of sudden cardiac death (SCD) by 300–400% depending on the severity of OSA. However published reports raised the association between OSA and SCD but not the mechanism of SCD. It is known that OSA exerts profound oxidative stress in the cardiovascular system. Repetitive nocturnal hypoxemia and arousals lead to ischemia reperfusion, cellular degeneration, and apoptosis, cardiac remodeling such as diastolic and systolic dysfunctions; which provide fertile environment for reentrant arrhythmias. Increase temporal dispersion in myocardial depolarization has been shown to enhance the genesis of malignant arrhythmias that in turn raise sudden death risk. We postulated that OSA leads to higher incidence of SCD due to reentrant arrhythmias initiated by ventricular extrasystoles that excite myocardial fibers at the height of its vulnerable period, reentrant beats trigger runs of ventricular tachycardia and ventricular fibrillation. Materials and methods: We deployed microvolt T-wave alternans (MTWA) as a tool to measure myocardial vulnerability. We attempted to determine if OSA leads to higher incidence of positive microvolt T-wave alternan (MTWA+); thus higher risk for arrhythmic death; and correlated MTWA result with severity of OSA as measured by apnea hypopnea index (AHI). 201 (M/F 1.1/1) patients with OSA of varying severity underwent MTWA in a random manner. We segmented the patients into MTWA positive (MTWA+), MTWA Indeterminate (MTWAI), MTWA negative (MTWA-). We then analyzed the MTWA result in relation to AHI. It has been shown that MTWA+ and MTWAI patients have higher risk of SCD usually from ischemia and cardiomyopathy. Results: There was a higher incidence of MTWA+ (p-value < 0.004) and MTWAI (p-value < 0.001) in severe OSA ‘‘AHI 30–50’’ and unusually severe OSA ‘‘AHI >50’’ MTWA+ (p-value < 0.003), MTWAI (p-value < 0.001 respectively). These two subgroups of OSA could be at higher risk for arrhythmic deaths since MTWA+ and MTWAI patients have higher mortality rate from malignant arrhythmias than MTWA . Conclution: sp020The severity of OSA is directly proportional to the incidence of MTWA positive (MTWA+) and MTWA indeterminate test (MTWAI). Severe and unusually severe OSA patients could be at higher risk of arrhythmic death than milder OSA as measured by MTWA. Acknowledgements: Cambridge Heart sold the equipment and supplies to Chanwell Clinic in the performance of MTWA test. http://dx.doi.org/10.1016/j.sleep.2013.11.201
Impact of continuous positive airway pressure (CPAP) on chronic cough in obstructive sleep apnoea (OSA) – A randomized controlled trial K. Chan 1, G. Cossa 2, S. Birring 3, L. Laks 4, A. Ing 4 1 Department of Respiratory Medicine, Campbelltown Hospital, University of Sydney, Australia 2 Respiratory Investigation Unit, Concord Repatriation General Hospital, Australia
Introduction: Recent studies have suggested that chronic cough is prevalent in patients with sleep- disordered breathing (SDB). We investigated the effect of continuous positive airway pressure (CPAP) on cough in patients with obstructive sleep apnoea (OSA) and chronic cough in a randomised controlled trial. Materials and methods: 22 consecutive patients with OSA confirmed on polysomnography (respiratory disturbance index (RDI) >15/h) and chronic cough >2 months were recruited. All patients underwent a CPAP titration study. 1 patient did not tolerate CPAP. 21 Patients were randomised to receive sham CPAP (4 cm H2O) or CPAP at pressures determined by the titration study for 1 month. The primary outcomes were objective 24-h cough count via the Leicester Cough Monitor (LCM), subjective cough severity via the visual analogue scale (VAS) and cough related quality of life via the Leicester Cough Questionnaire (LCQ). Results: 13 (7 males) patients received sham CPAP and 8 (6 males) received titrated CPAP. There were no significant differences between groups [sham vs CPAP mean (SD)] in age [54.5 (2.8) years vs 59.9 (5.2) years, p = 0.34], BMI [37.4 (1.9) vs 32.5 (1.3), p = 0.08], RDI [41.5 (7.4) vs 36.5 (6.7), p = 0.65], baseline 24-h cough count [302.9 (66.0) vs 257.4 (57.5), p = 0.64],VAS [56.9 (6.9) vs 54.3 (6.7), in mm] and LCQ score [14.0 (1.0) vs 14.3 (1.3)]. After 1 month there were no significant changes in 24-h cough count in the sham CPAP group [ 93.9 (222.2), p = 0.15] but there was significant improvement in the titrated CPAP group [ 192.6 (162.1), p = 0.01]. There were no significant changes in VAS in the sham CPAP group [ 9.9 (28.5), p = 0.25] but there was significant improvement in the titrated CPAP group [ 26.75 (31.9), p = 0.05]. There were no significant changes in LCQ in the sham CPAP group [ 0.50 (5.0), p = 0.73] or titrated CPAP group [ 1.47 (5.1), p = 0.44]. Conclusion: CPAP may reduce objective and subjective cough severity in patients with cough associated with OSA. Acknowledgements: University of Western Sydney. http://dx.doi.org/10.1016/j.sleep.2013.11.202
Chan score predicts presence and severity of sleep apnea at the bedside before polysomnogram sleep test M. Chan 1, A. Chan 2, A. Ly 2, N. Lim 2 1 Internal Medicine, Yale New Hospital, United States 2 Chanwell Clinic Institute for Heart & Sleep Disorders, United States
Introduction: Obstructive sleep apnea–hypopnea (OSAH) increases the risk for metabolic syndrome, heart failure, myocardial infarction, stroke, sudden cardiac death and vehicular accidents. In spite of the wide prevalence of OSAH, physicians often miss the signs and symptoms of OSAH, thus a large number of undiagnosed patients remain at great risks. Furthermore, most effective methods of diagnosing OSAH or identifying its symptoms require the observation of a sleep technician, an overnight in-lab polysomnogram, and/or a portable home sleep-monitor which can be both costly and time consuming. As a result, we devised a method of predicting OSAH by assigning weighted numerical values that considers a patient’s age, history of snoring, Epworth Sleepiness Scale (ESS), body mass index (BMI), and upper airway structure (Mallampati classification). Purpose: To predict the presence and severity of OSAH (in the form of an AHI
http://dx.doi.org/10.1016/j.sleep.2013.11.200
e95
3
Department of Respiratory Medicine, King’s College Hospital, Australia Department of Thoracic Medicine, Concord Repatriation General Hospital, University of Sydney, Australia 4
Mechanism of sudden cardiac death in obstructive sleep apnea, revisited A. Chan 1, N. Antonio 2 1 Chanwell Clinic Institute for Heart & Sleep Disorders, Stanford University School of Medicine (1993–2012), United States 2 Chanwell Clinic Institute for Heart & Sleep Disorders, United States
Introduction: Obstructive sleep apnea (OSA) raises the risk of sudden cardiac death (SCD) by 300–400% depending on the severity of OSA. However published reports raised the association between OSA and SCD but not the mechanism of SCD. It is known that OSA exerts profound oxidative stress in the cardiovascular system. Repetitive nocturnal hypoxemia and arousals lead to ischemia reperfusion, cellular degeneration, and apoptosis, cardiac remodeling such as diastolic and systolic dysfunctions; which provide fertile environment for reentrant arrhythmias. Increase temporal dispersion in myocardial depolarization has been shown to enhance the genesis of malignant arrhythmias that in turn raise sudden death risk. We postulated that OSA leads to higher incidence of SCD due to reentrant arrhythmias initiated by ventricular extrasystoles that excite myocardial fibers at the height of its vulnerable period, reentrant beats trigger runs of ventricular tachycardia and ventricular fibrillation. Materials and methods: We deployed microvolt T-wave alternans (MTWA) as a tool to measure myocardial vulnerability. We attempted to determine if OSA leads to higher incidence of positive microvolt T-wave alternan (MTWA+); thus higher risk for arrhythmic death; and correlated MTWA result with severity of OSA as measured by apnea hypopnea index (AHI). 201 (M/F 1.1/1) patients with OSA of varying severity underwent MTWA in a random manner. We segmented the patients into MTWA positive (MTWA+), MTWA Indeterminate (MTWAI), MTWA negative (MTWA-). We then analyzed the MTWA result in relation to AHI. It has been shown that MTWA+ and MTWAI patients have higher risk of SCD usually from ischemia and cardiomyopathy. Results: There was a higher incidence of MTWA+ (p-value < 0.004) and MTWAI (p-value < 0.001) in severe OSA ‘‘AHI 30–50’’ and unusually severe OSA ‘‘AHI >50’’ MTWA+ (p-value < 0.003), MTWAI (p-value < 0.001 respectively). These two subgroups of OSA could be at higher risk for arrhythmic deaths since MTWA+ and MTWAI patients have higher mortality rate from malignant arrhythmias than MTWA . Conclution: sp020The severity of OSA is directly proportional to the incidence of MTWA positive (MTWA+) and MTWA indeterminate test (MTWAI). Severe and unusually severe OSA patients could be at higher risk of arrhythmic death than milder OSA as measured by MTWA. Acknowledgements: Cambridge Heart sold the equipment and supplies to Chanwell Clinic in the performance of MTWA test. http://dx.doi.org/10.1016/j.sleep.2013.11.201
Impact of continuous positive airway pressure (CPAP) on chronic cough in obstructive sleep apnoea (OSA) – A randomized controlled trial K. Chan 1, G. Cossa 2, S. Birring 3, L. Laks 4, A. Ing 4 1 Department of Respiratory Medicine, Campbelltown Hospital, University of Sydney, Australia 2 Respiratory Investigation Unit, Concord Repatriation General Hospital, Australia
Introduction: Recent studies have suggested that chronic cough is prevalent in patients with sleep- disordered breathing (SDB). We investigated the effect of continuous positive airway pressure (CPAP) on cough in patients with obstructive sleep apnoea (OSA) and chronic cough in a randomised controlled trial. Materials and methods: 22 consecutive patients with OSA confirmed on polysomnography (respiratory disturbance index (RDI) >15/h) and chronic cough >2 months were recruited. All patients underwent a CPAP titration study. 1 patient did not tolerate CPAP. 21 Patients were randomised to receive sham CPAP (4 cm H2O) or CPAP at pressures determined by the titration study for 1 month. The primary outcomes were objective 24-h cough count via the Leicester Cough Monitor (LCM), subjective cough severity via the visual analogue scale (VAS) and cough related quality of life via the Leicester Cough Questionnaire (LCQ). Results: 13 (7 males) patients received sham CPAP and 8 (6 males) received titrated CPAP. There were no significant differences between groups [sham vs CPAP mean (SD)] in age [54.5 (2.8) years vs 59.9 (5.2) years, p = 0.34], BMI [37.4 (1.9) vs 32.5 (1.3), p = 0.08], RDI [41.5 (7.4) vs 36.5 (6.7), p = 0.65], baseline 24-h cough count [302.9 (66.0) vs 257.4 (57.5), p = 0.64],VAS [56.9 (6.9) vs 54.3 (6.7), in mm] and LCQ score [14.0 (1.0) vs 14.3 (1.3)]. After 1 month there were no significant changes in 24-h cough count in the sham CPAP group [ 93.9 (222.2), p = 0.15] but there was significant improvement in the titrated CPAP group [ 192.6 (162.1), p = 0.01]. There were no significant changes in VAS in the sham CPAP group [ 9.9 (28.5), p = 0.25] but there was significant improvement in the titrated CPAP group [ 26.75 (31.9), p = 0.05]. There were no significant changes in LCQ in the sham CPAP group [ 0.50 (5.0), p = 0.73] or titrated CPAP group [ 1.47 (5.1), p = 0.44]. Conclusion: CPAP may reduce objective and subjective cough severity in patients with cough associated with OSA. Acknowledgements: University of Western Sydney. http://dx.doi.org/10.1016/j.sleep.2013.11.202
Chan score predicts presence and severity of sleep apnea at the bedside before polysomnogram sleep test M. Chan 1, A. Chan 2, A. Ly 2, N. Lim 2 1 Internal Medicine, Yale New Hospital, United States 2 Chanwell Clinic Institute for Heart & Sleep Disorders, United States
Introduction: Obstructive sleep apnea–hypopnea (OSAH) increases the risk for metabolic syndrome, heart failure, myocardial infarction, stroke, sudden cardiac death and vehicular accidents. In spite of the wide prevalence of OSAH, physicians often miss the signs and symptoms of OSAH, thus a large number of undiagnosed patients remain at great risks. Furthermore, most effective methods of diagnosing OSAH or identifying its symptoms require the observation of a sleep technician, an overnight in-lab polysomnogram, and/or a portable home sleep-monitor which can be both costly and time consuming. As a result, we devised a method of predicting OSAH by assigning weighted numerical values that considers a patient’s age, history of snoring, Epworth Sleepiness Scale (ESS), body mass index (BMI), and upper airway structure (Mallampati classification). Purpose: To predict the presence and severity of OSAH (in the form of an AHI