STUDY OBJECTIVES: To determine the impact of averaging window-length on the "desaturation" indexes (DIs) obtained via overnight pulse oximetry (SpO2) at high altitude. DESIGN: Overnight SpO2 data were collected during a 10-day sojourn at high altitude. SpO2 was obtained using a commercial wrist-worn finger oximeter whose firmware was modified to store unaveraged beat-to-beat data. Simple moving averages of window lengths spanning 2 to 20 cardiac beats were retrospectively applied to beat-to-beat SpO2 datasets. After SpO2 artifacts were removed, the following DIs were then calculated for each of the averaged datasets: oxygen desaturation index (ODI); total sleep time with SpO2 < 80% (TST < 80), and the lowest SpO2 observed during sleep (SpO2 low). SETTING: South Base Camp, Mt. Everest (5,364 m elevation). PARTICIPANTS: Five healthy, adult males (35 ± 5 y; 180 ± 1 cm; 85 ± 4 kg). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: 49 datasets were obtained from the 5 participants, totalling 239 hours of data. For all window lengths ≥ 2 beats, ODI and TST < 80 were lower, and SpO2 low was higher than those values obtained from the beat-to-beat SpO2 time series data (P < 0.05). CONCLUSIONS: Our findings indicate that increasing oximeter averaging window length progressively underestimates the frequency and magnitude of sleep disordered breathing events at high altitude, as indirectly assessed via the desaturation indexes.
STUDY OBJECTIVES: To determine the impact of averaging window-length on the "desaturation" indexes (DIs) obtained via overnight pulse oximetry (SpO2) at high altitude. DESIGN: Overnight SpO2 data were collected during a 10-day sojourn at high altitude. SpO2 was obtained using a commercial wrist-worn finger oximeter whose firmware was modified to store unaveraged beat-to-beat data. Simple moving averages of window lengths spanning 2 to 20 cardiac beats were retrospectively applied to beat-to-beat SpO2 datasets. After SpO2 artifacts were removed, the following DIs were then calculated for each of the averaged datasets: oxygen desaturation index (ODI); total sleep time with SpO2 < 80% (TST < 80), and the lowest SpO2 observed during sleep (SpO2 low). SETTING: South Base Camp, Mt. Everest (5,364 m elevation). PARTICIPANTS: Five healthy, adult males (35 ± 5 y; 180 ± 1 cm; 85 ± 4 kg). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: 49 datasets were obtained from the 5 participants, totalling 239 hours of data. For all window lengths ≥ 2 beats, ODI and TST < 80 were lower, and SpO2 low was higher than those values obtained from the beat-to-beat SpO2 time series data (P < 0.05). CONCLUSIONS: Our findings indicate that increasing oximeter averaging window length progressively underestimates the frequency and magnitude of sleep disordered breathing events at high altitude, as indirectly assessed via the desaturation indexes.
Authors: Valdir de Aquino Lemos; Hanna Karen Moreira Antunes; Ronaldo Vagner Thomatieli dos Santos; Fabio Santos Lira; Sergio Tufik; Marco Túlio de Mello Journal: Psychophysiology Date: 2012-07-16 Impact factor: 4.016
Authors: David G Davila; Kathy C Richards; Buddy L Marshall; Patricia S O'Sullivan; Leah A Osbahr; Regina B Huddleston; Jay C Jordan Journal: Sleep Date: 2003-02-01 Impact factor: 5.849
Authors: David G Davila; Kathy C Richards; Buddy L Marshall; Patricia S O'Sullivan; Ty G Gregory; Valerie J Hernandez; Shirley I Rice Journal: Chest Date: 2002-11 Impact factor: 9.410
Authors: Timon M Fabius; Jeffrey R Benistant; Lindsey Bekkedam; Job van der Palen; Frans H C de Jongh; Michiel M M Eijsvogel Journal: Sleep Breath Date: 2018-03-21 Impact factor: 2.816