R B Govindan1, An Massaro2, Gilbert Vezina3, Taeun Chang4, Adre du Plessis5. 1. Fetal Medicine Institute, Children's National Medical Center, Washington, DC, USA; The George Washington University School of Medicine, USA. Electronic address: rgovinda@childrensnational.org. 2. The George Washington University School of Medicine, USA; Neonatology, Children's National Medical Center, Washington, DC, USA. 3. The George Washington University School of Medicine, USA; Diagnostic Imaging and Radiology, Children's National Medical Center, Washington, DC, USA. 4. The George Washington University School of Medicine, USA; Neurology, Children's Medical Center, Washington, DC, USA. 5. Fetal Medicine Institute, Children's National Medical Center, Washington, DC, USA; The George Washington University School of Medicine, USA.
Abstract
BACKGROUND AND OBJECTIVE: To identify the optimal epoch length for power spectral analysis of cardiac beat-to-beat intervals (BBi) in critically ill newborns. MATERIALS AND METHOD: BBi of 49 term newborns undergoing therapeutic hypothermia for hypoxic-ischemic encephalopathy with well-defined outcomes (good outcome (n = 28): no or mild brain injury and adverse outcome (n = 21): moderate or severe brain injury or death) served as test population. A power spectrum of BBi was calculated with an autoregressive model in three different epoch lengths: 2 min, 5 min, and 10 min. Spectral power was quantified in three different frequency bands: very low-frequency (0.016-0.04 Hz), low-frequency (0.05-0.25 Hz), and high-frequency (0.3-1 Hz). In each frequency band, the absolute power and the normalized power were calculated. Furthermore, standard deviation (SDNN) of BBi was calculated. These metrics were compared between the outcome groups with a receiver operator characteristic (ROC) analysis in 3-h windows. The ROC curve area >0.7 was regarded as a significant separation. RESULTS: The absolute spectral powers in all three epoch lengths in all three frequency bands and SDNN distinguished the two outcome groups consistently for most time points. The spectral metrics calculated with a 2-min epoch length performed as well as the five- and 10-min epoch lengths (paired t-test P < 0.05). CONCLUSION: Spectral analysis of BBi in 2-min epoch shows a similar discriminatory power as longer epoch lengths. A shorter epoch also has clinical advantages for translation into a continuous real-time bedside monitor of heart rate variability in the intensive care unit.
BACKGROUND AND OBJECTIVE: To identify the optimal epoch length for power spectral analysis of cardiac beat-to-beat intervals (BBi) in critically ill newborns. MATERIALS AND METHOD:BBi of 49 term newborns undergoing therapeutic hypothermia for hypoxic-ischemic encephalopathy with well-defined outcomes (good outcome (n = 28): no or mild brain injury and adverse outcome (n = 21): moderate or severe brain injury or death) served as test population. A power spectrum of BBi was calculated with an autoregressive model in three different epoch lengths: 2 min, 5 min, and 10 min. Spectral power was quantified in three different frequency bands: very low-frequency (0.016-0.04 Hz), low-frequency (0.05-0.25 Hz), and high-frequency (0.3-1 Hz). In each frequency band, the absolute power and the normalized power were calculated. Furthermore, standard deviation (SDNN) of BBi was calculated. These metrics were compared between the outcome groups with a receiver operator characteristic (ROC) analysis in 3-h windows. The ROC curve area >0.7 was regarded as a significant separation. RESULTS: The absolute spectral powers in all three epoch lengths in all three frequency bands and SDNN distinguished the two outcome groups consistently for most time points. The spectral metrics calculated with a 2-min epoch length performed as well as the five- and 10-min epoch lengths (paired t-test P < 0.05). CONCLUSION: Spectral analysis of BBi in 2-min epoch shows a similar discriminatory power as longer epoch lengths. A shorter epoch also has clinical advantages for translation into a continuous real-time bedside monitor of heart rate variability in the intensive care unit.
Authors: Stephanie R Yiallourou; Hannah Poole; Pallavi Prathivadi; Alexsandria Odoi; Flora Y Wong; Rosemary S C Horne Journal: Sleep Med Date: 2014-09-02 Impact factor: 3.492
Authors: Seetha Shankaran; Abbot R Laptook; Richard A Ehrenkranz; Jon E Tyson; Scott A McDonald; Edward F Donovan; Avroy A Fanaroff; W Kenneth Poole; Linda L Wright; Rosemary D Higgins; Neil N Finer; Waldemar A Carlo; Shahnaz Duara; William Oh; C Michael Cotten; David K Stevenson; Barbara J Stoll; James A Lemons; Ronnie Guillet; Alan H Jobe Journal: N Engl J Med Date: 2005-10-13 Impact factor: 91.245
Authors: Umit D Ulusar; R B Govindan; James D Wilson; Curtis L Lowery; Hubert Preissl; Hari Eswaran Journal: Conf Proc IEEE Eng Med Biol Soc Date: 2009