Bradycardias are associated with more severe effects on cerebral oxygenation in very preterm infants than in late preterm infants

Lisa M. Walter, Bushra Ahmed, Alexsandria Odoi, Hannah Cooney, Rosemary S.C. Horne, Flora Y. Wong

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Background: Commonly the magnitude and frequency of bradycardia is underestimated in the neonatal unit due to the long averaging time used in bedside oximeters. We aimed to assess the frequency and severity of bradycardia in preterm infants using the lowest averaging time (2 s) available on a clinical oximeter, compared with bradycardia detected using electrocardiogram (ECG), and whether bradycardia severity and postmenstrual age affected cerebral oxygenation. Methods: Preterm infants (10 M/9F) were studied longitudinally at 26–31 (very preterm) and 32–38 weeks (late preterm) postmenstrual age. Heart rate falls calculated from ECG were used to determine mild or moderate/severe (MS) bradycardias. Cerebral tissue oxygenation index (TOI, %) was recorded and fractional tissue oxygen extraction (FTOE) calculated. Results: Of the 615 bradycardias scored using ECG criteria, 10% were not detected by oximetry. TOI falls associated with bradycardias were greater for MS bradycardias compared with Mild for both groups (p < 0.001 for both). The FTOE associated with MS bradycardias was higher for the very preterm compared with the late preterm group (p < 0.001). In very preterm infants 61% of MS and 35% Mild bradycardias were associated with TOI nadirs below 55%. Conclusion: Even the most sensitive oximeter setting underestimates bradycardias. The cerebral effect from bradycardias in very preterm infants is more severe than in late preterm infants. Even the mild bradycardias are associated with falls in cerebral oxygenation. Routine NIRS monitoring of cerebral oxygenation in NICUs may increase staff awareness for interventions to reduce the repetitive falls in cerebral oxygenation in preterm infants.

Original languageEnglish
Pages (from-to)33-41
Number of pages9
JournalEarly Human Development
Volume127
DOIs
Publication statusPublished - 1 Dec 2018

Keywords

  • Cardiovascular
  • Neonatal
  • Oximetry
  • Tissue oxygenation index

Cite this

@article{e59473b576364adfbe56331591eb7116,
title = "Bradycardias are associated with more severe effects on cerebral oxygenation in very preterm infants than in late preterm infants",
abstract = "Background: Commonly the magnitude and frequency of bradycardia is underestimated in the neonatal unit due to the long averaging time used in bedside oximeters. We aimed to assess the frequency and severity of bradycardia in preterm infants using the lowest averaging time (2 s) available on a clinical oximeter, compared with bradycardia detected using electrocardiogram (ECG), and whether bradycardia severity and postmenstrual age affected cerebral oxygenation. Methods: Preterm infants (10 M/9F) were studied longitudinally at 26–31 (very preterm) and 32–38 weeks (late preterm) postmenstrual age. Heart rate falls calculated from ECG were used to determine mild or moderate/severe (MS) bradycardias. Cerebral tissue oxygenation index (TOI, {\%}) was recorded and fractional tissue oxygen extraction (FTOE) calculated. Results: Of the 615 bradycardias scored using ECG criteria, 10{\%} were not detected by oximetry. TOI falls associated with bradycardias were greater for MS bradycardias compared with Mild for both groups (p < 0.001 for both). The FTOE associated with MS bradycardias was higher for the very preterm compared with the late preterm group (p < 0.001). In very preterm infants 61{\%} of MS and 35{\%} Mild bradycardias were associated with TOI nadirs below 55{\%}. Conclusion: Even the most sensitive oximeter setting underestimates bradycardias. The cerebral effect from bradycardias in very preterm infants is more severe than in late preterm infants. Even the mild bradycardias are associated with falls in cerebral oxygenation. Routine NIRS monitoring of cerebral oxygenation in NICUs may increase staff awareness for interventions to reduce the repetitive falls in cerebral oxygenation in preterm infants.",
keywords = "Cardiovascular, Neonatal, Oximetry, Tissue oxygenation index",
author = "Walter, {Lisa M.} and Bushra Ahmed and Alexsandria Odoi and Hannah Cooney and Horne, {Rosemary S.C.} and Wong, {Flora Y.}",
year = "2018",
month = "12",
day = "1",
doi = "10.1016/j.earlhumdev.2018.08.008",
language = "English",
volume = "127",
pages = "33--41",
journal = "Early Human Development",
issn = "0378-3782",
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Bradycardias are associated with more severe effects on cerebral oxygenation in very preterm infants than in late preterm infants. / Walter, Lisa M.; Ahmed, Bushra; Odoi, Alexsandria; Cooney, Hannah; Horne, Rosemary S.C.; Wong, Flora Y.

In: Early Human Development, Vol. 127, 01.12.2018, p. 33-41.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Bradycardias are associated with more severe effects on cerebral oxygenation in very preterm infants than in late preterm infants

AU - Walter, Lisa M.

AU - Ahmed, Bushra

AU - Odoi, Alexsandria

AU - Cooney, Hannah

AU - Horne, Rosemary S.C.

AU - Wong, Flora Y.

PY - 2018/12/1

Y1 - 2018/12/1

N2 - Background: Commonly the magnitude and frequency of bradycardia is underestimated in the neonatal unit due to the long averaging time used in bedside oximeters. We aimed to assess the frequency and severity of bradycardia in preterm infants using the lowest averaging time (2 s) available on a clinical oximeter, compared with bradycardia detected using electrocardiogram (ECG), and whether bradycardia severity and postmenstrual age affected cerebral oxygenation. Methods: Preterm infants (10 M/9F) were studied longitudinally at 26–31 (very preterm) and 32–38 weeks (late preterm) postmenstrual age. Heart rate falls calculated from ECG were used to determine mild or moderate/severe (MS) bradycardias. Cerebral tissue oxygenation index (TOI, %) was recorded and fractional tissue oxygen extraction (FTOE) calculated. Results: Of the 615 bradycardias scored using ECG criteria, 10% were not detected by oximetry. TOI falls associated with bradycardias were greater for MS bradycardias compared with Mild for both groups (p < 0.001 for both). The FTOE associated with MS bradycardias was higher for the very preterm compared with the late preterm group (p < 0.001). In very preterm infants 61% of MS and 35% Mild bradycardias were associated with TOI nadirs below 55%. Conclusion: Even the most sensitive oximeter setting underestimates bradycardias. The cerebral effect from bradycardias in very preterm infants is more severe than in late preterm infants. Even the mild bradycardias are associated with falls in cerebral oxygenation. Routine NIRS monitoring of cerebral oxygenation in NICUs may increase staff awareness for interventions to reduce the repetitive falls in cerebral oxygenation in preterm infants.

AB - Background: Commonly the magnitude and frequency of bradycardia is underestimated in the neonatal unit due to the long averaging time used in bedside oximeters. We aimed to assess the frequency and severity of bradycardia in preterm infants using the lowest averaging time (2 s) available on a clinical oximeter, compared with bradycardia detected using electrocardiogram (ECG), and whether bradycardia severity and postmenstrual age affected cerebral oxygenation. Methods: Preterm infants (10 M/9F) were studied longitudinally at 26–31 (very preterm) and 32–38 weeks (late preterm) postmenstrual age. Heart rate falls calculated from ECG were used to determine mild or moderate/severe (MS) bradycardias. Cerebral tissue oxygenation index (TOI, %) was recorded and fractional tissue oxygen extraction (FTOE) calculated. Results: Of the 615 bradycardias scored using ECG criteria, 10% were not detected by oximetry. TOI falls associated with bradycardias were greater for MS bradycardias compared with Mild for both groups (p < 0.001 for both). The FTOE associated with MS bradycardias was higher for the very preterm compared with the late preterm group (p < 0.001). In very preterm infants 61% of MS and 35% Mild bradycardias were associated with TOI nadirs below 55%. Conclusion: Even the most sensitive oximeter setting underestimates bradycardias. The cerebral effect from bradycardias in very preterm infants is more severe than in late preterm infants. Even the mild bradycardias are associated with falls in cerebral oxygenation. Routine NIRS monitoring of cerebral oxygenation in NICUs may increase staff awareness for interventions to reduce the repetitive falls in cerebral oxygenation in preterm infants.

KW - Cardiovascular

KW - Neonatal

KW - Oximetry

KW - Tissue oxygenation index

UR - http://www.scopus.com/inward/record.url?scp=85053787496&partnerID=8YFLogxK

U2 - 10.1016/j.earlhumdev.2018.08.008

DO - 10.1016/j.earlhumdev.2018.08.008

M3 - Article

VL - 127

SP - 33

EP - 41

JO - Early Human Development

JF - Early Human Development

SN - 0378-3782

ER -