Daniel Vena1,2, T Douglas Bradley1,3, Philip J Millar4,5, John S Floras3,4, Jonathan Rubianto1, Bojan Gavrilovic1, Elisa Perger1, Azadeh Yadollahi1,2. 1. Toronto Rehabilitation Institute - University Health Network, Toronto, Canada. 2. Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada. 3. Department of Medicine, University of Toronto, Toronto, Canada. 4. Toronto General Research Institute, University Health Network, Toronto, Canada. 5. Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
Abstract
STUDY OBJECTIVES: Postoperative development of obstructive sleep apnea (OSA) has been attributed to the fluid overloaded state of patients during the postoperative period. In this context, alterations in cardiac autonomic regulation caused by OSA may explain the increased postoperative risk for adverse cardiovascular events. This study tests the hypothesis that individuals with fluid overload-induced OSA will experience autonomic dysregulation, compared to those without fluid overload-induced OSA. METHODS:Twenty-one normotensive, nonobese (mean body mass index 24.5 kg/m2) males (mean age 37 years) underwent a sleep study. Participants were randomly assigned to infusion with saline during sleep either at the minimum rate (control) or as a bolus of 22 mL/kg body weight (intervention). Participants were blinded to the intervention and crossed over to the other study arm after 1 week. Measures of heart rate variability were calculated from electrocardiography recordings presaline and postsaline infusion in the intervention arm. Heart rate variability measures computed were: standard deviation of the RR interval; root mean square of successive differences; low-frequency, high-frequency, and total power; and the ratio of low-frequency to high-frequency power. RESULTS: Although presaline infusion values were similar, postsaline infusion values of the standard deviation of the RR interval and high-frequency power were lower in the group whose apnea-hypopnea index increased in response to saline infusion, compared to the group whose apnea-hypopnea index did not increase in response to saline infusion (P < .05 for both). CONCLUSIONS: Fluid overload-induced OSA is accompanied by a reduction in heart rate variability, consistent with vagal withdrawal. Future work should explore autonomic dysregulation in the postoperative period and its association with adverse events.
RCT Entities:
STUDY OBJECTIVES: Postoperative development of obstructive sleep apnea (OSA) has been attributed to the fluid overloaded state of patients during the postoperative period. In this context, alterations in cardiac autonomic regulation caused by OSA may explain the increased postoperative risk for adverse cardiovascular events. This study tests the hypothesis that individuals with fluid overload-induced OSA will experience autonomic dysregulation, compared to those without fluid overload-induced OSA. METHODS: Twenty-one normotensive, nonobese (mean body mass index 24.5 kg/m2) males (mean age 37 years) underwent a sleep study. Participants were randomly assigned to infusion with saline during sleep either at the minimum rate (control) or as a bolus of 22 mL/kg body weight (intervention). Participants were blinded to the intervention and crossed over to the other study arm after 1 week. Measures of heart rate variability were calculated from electrocardiography recordings presaline and postsaline infusion in the intervention arm. Heart rate variability measures computed were: standard deviation of the RR interval; root mean square of successive differences; low-frequency, high-frequency, and total power; and the ratio of low-frequency to high-frequency power. RESULTS: Although presaline infusion values were similar, postsaline infusion values of the standard deviation of the RR interval and high-frequency power were lower in the group whose apnea-hypopnea index increased in response to saline infusion, compared to the group whose apnea-hypopnea index did not increase in response to saline infusion (P < .05 for both). CONCLUSIONS: Fluid overload-induced OSA is accompanied by a reduction in heart rate variability, consistent with vagal withdrawal. Future work should explore autonomic dysregulation in the postoperative period and its association with adverse events.
Authors: Takatoshi Kasai; Shveta S Motwani; Dai Yumino; Susanna Mak; Gary E Newton; T Douglas Bradley Journal: Circ Heart Fail Date: 2012-06-07 Impact factor: 8.790
Authors: Thomas Penzel; Jan W Kantelhardt; Ludger Grote; Jörg-Hermann Peter; Armin Bunde Journal: IEEE Trans Biomed Eng Date: 2003-10 Impact factor: 4.538
Authors: Azadeh Yadollahi; Joseph M Gabriel; Laura H White; Luigi Taranto Montemurro; Takatoshi Kasai; T Douglas Bradley Journal: Sleep Date: 2014-10-01 Impact factor: 5.849