Heart rate variability of transported critically ill neonates

Neonatal heart rate variability: a contemporary scoping review of analysis methods and clinical applications

BACKGROUND

Neonatal heart rate variability (HRV) is widely used as a research tool. However, HRV calculation methods are highly variable making it difficult for comparisons between studies.

OBJECTIVES

To describe the different types of investigations where neonatal HRV was used, study characteristics, and types of analyses performed.

ELIGIBILITY CRITERIA

Human neonates ≤1 month of corrected age.

SOURCES OF EVIDENCE

A protocol and search strategy of the literature was developed in collaboration with the McGill University Health Center's librarians and articles were obtained from searches in the Biosis, Cochrane, Embase, Medline and Web of Science databases published between 1 January 2000 and 1 July 2020.

CHARTING METHODS

A single reviewer screened for eligibility and data were extracted from the included articles. Information collected included the study characteristics and population, type of HRV analysis used (time domain, frequency domain, non-linear, heart rate characteristics (HRC) parameters) and clinical applications (physiological and pathological conditions, responses to various stimuli and outcome prediction).

RESULTS

Of the 286 articles included, 171 (60%) were small single centre studies (sample size <50) performed on term infants (n=136). There were 138 different types of investigations reported: physiological investigations (n=162), responses to various stimuli (n=136), pathological conditions (n=109) and outcome predictor (n=30). Frequency domain analyses were used in 210 articles (73%), followed by time domain (n=139), non-linear methods (n=74) or HRC analyses (n=25). Additionally, over 60 different measures of HRV were reported; in the frequency domain analyses alone there were 29 different ranges used for the low frequency band and 46 for the high frequency band.

CONCLUSIONS

Neonatal HRV has been used in diverse types of investigations with significant lack of consistency in analysis methods applied. Specific guidelines for HRV analyses in neonates are needed to allow for comparisons between studies.

The effect of sleeping position on heart rate variability in newborns

Background

Lower heart rate variability (HRV) in a newborn might represent a risk factor for unfavourable outcome, a longer recovery after illness, and a sudden infant death. Our aim was to determine whether the newborn’s sleeping position is associated with HRV.

Methods

We performed a prospective clinical study in 46 hospitalized cardiorespiratory stable term newborns. During sleeping, we measured the parameters of HRV in four body positions (supine, supine with tilt, prone, prone with tilt).

Results

The TP (total power spectral density) was significantly higher when lying supine in comparison to prone (p = 0,048) and to prone with tilt (p = 0,046). The HF (high frequency of power spectral density) in the supine position without tilt tended to be higher compared to prone without tilt (p > 0,05). The LF (low frequency power) was significantly higher when lying supine compared to prone, both without tilt (p = 0,018). TP and HF showed a positive correlation with gestational but not postmenstrual age (p = 0.044 and p = 0.036, respectively).

Conclusions

In term newborns, sleeping position is associated with HRV. Higher TP and HF were found in the supine position, which might reflect better ANS stability. Gestational age positively correlated with TP and HF power, but only in supine position.

Trial registration

ISRCTN11702082, date of registration: March, 13th, 2020; retrospectively registered.

Pilot Testing a Robot for Reducing Pain in Hospitalized Preterm Infants

Optimizing neurodevelopment is a key goal of neonatal occupational therapy. In preterm infants, repeated procedural pain is associated with adverse effects on neurodevelopment long term. Calmer is a robot designed to reduce infant pain. The objective of this study was to examine the effects of Calmer on heart rate variability (HRV) during routine blood collection in preterm infants. In a randomized controlled pilot trial, 10 infants were assigned to either standard care ( n = 5, facilitated tucking [FT]) or Calmer treatment ( n = 5). HRV was recorded continuously and quantified using the area (power) of the spectrum in high and low frequency (HF: 0.15-0.40Hz/ms2; LF: 0.04-0.15 Hz/ms2) regions. Changes in HRV during three, 2-min phases (Baseline, Heel Poke, and Recovery) were compared between groups. Calmer infants had 90% greater parasympathetic activation ([PS] reduced stress) during Baseline, 82% greater PS activation during Poke, and 24% greater PS activation during Recovery than FT infants. Calmer reduced physiological preterm infant pain reactivity during blood collection.

Passive therapeutic hypothermia during ambulance and helicopter secondary neonatal transport in neonates with hypoxic brain injury: a 10-year retrospective survey

BACKGROUND

Therapeutic hypothermia is a method of treatment in newborns with hypoxic ischemic encephalopathy. Hypothermia should be initiated no later than 6 h after birth. The purpose of this study was to evaluate the quality of the passive therapeutic cooling during neonatal transport.

PURPOSE

The study aims to evaluate the efficiency of our transport in maintenance of target body temperature during transport.

METHODS

We conducted a 10-year retrospective study in neonates, transported by helicopter or ambulance, who received therapeutic passive-induced hypothermia during transport to the Department of Pediatric Surgery and Intensive Therapy at the University Medical Centre Ljubljana between September 1, 2006, and December 31, 2016.

RESULTS

Out of 68 transported newborns, 57 met the criteria for therapeutic induced hypothermia. Eight out of 51 (15.7%) were within therapeutic temperature zone before start of transport while 30 out of 57 (52.6%) were within therapeutic temperature zone at the end of transport. There was a negative correlation between the duration of transport and temperature at the admission (ρ = - 0.306; p = 0.026). A positive correlation was found between the body temperature before and at the end of transport (ρ = 0.410; p = 0,003). A positive correlation between axillary and rectal temperature on admission was found (ρ = 0,832; p < 0,0005). The type of transport, meteorological season, or gender differences did not affect any of measured parameters. Newborns who received chest compression had lower temperature.

CONCLUSION

Therapeutic temperature zone during transport was achieved in 52.6% of transported neonates. Axillary temperature positively correlated with rectal temperature on admission.