Body temperature instability and respiratory morbidity in the very low birth weight infant: a multiple case, intensive longitudinal study

Jane L Ralphe,Susan G Silva,Robin B Dail,Debra H Brandon

doi:10.1186/s12887-020-02351-y

Jane L Ralphe, Susan G Silva + Show 2 more

Open Access

https://doi.org/10.1186/s12887-020-02351-y

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Abstract

BackgroundVery low birth weight (VLBW) infant thermal instability upon neonatal intensive care unit admission has been associated with respiratory morbidity; however, the association between ongoing thermal instability and respiratory morbidity remains unclear.MethodsA longitudinal data analysis was conducted on 12 VLBW infants. Chronic respiratory morbidity risk was defined as supplemental oxygen requirement (FiO2) or scheduled diuretic dosing at 36 weeks post-menstrual age. Acute respiratory morbidity was quantified as desaturations (SpO2<90%), bradycardia with desaturations (HR<100 and SpO2<90%), apnea, increase in FiO2 requirement, or increase in respiratory support. Multi-level, mixed-effects models and regression analysis examined the relationships between body temperature over the first 14 days of life and respiratory morbidities.ResultsBody temperature was not associated with chronic respiratory morbidity risk (p=0.2765). Desaturations, bradycardia with desaturations, increased FiO2 requirement, and increased respiratory support were associated with decreased body temperature (p<0.05). Apnea was associated with increased body temperature (p<0.05). The covariate-adjusted risk of desaturations (aOR=1.3), bradycardia with desaturations (aOR=2.2), increase in FiO2 requirement (aOR=1.2), and increase in respiratory support (aOR=1.2) were significantly greater during episodes of hypothermia.ConclusionVLBW infants are dependent on a neutral thermal environment for optimal growth and development. Therefore, the significant associations between hypothermia and symptoms of acute respiratory morbidity require further study to delineate if these are causal relationships that could be attenuated with clinical practice changes, or if these are concurrent symptoms that cluster during episodes of physiological instability.

Highlights

Very low birth weight (VLBW) infant thermal instability upon neonatal intensive care unit admission has been associated with respiratory morbidity; the association between ongoing thermal instability and respiratory morbidity remains unclear
This study examined the association between VLBW infant body temperatures and both chronic respiratory morbidity risk (CRMR) (i.e., Fraction of inspired oxygen (FiO2) requirement or scheduled diuretic use at 36 weeks postmenstrual age (PMA) and biomarkers for acute respiratory morbidity
Body temperatures and chronic respiratory morbidity risk Descriptive statistics were used to examine the association between episodes of hypothermia and hyperthermia with the outcome of Chronic respiratory morbidity risk (CRMR)

Summary

Introduction

Very low birth weight (VLBW) infant thermal instability upon neonatal intensive care unit admission has been associated with respiratory morbidity; the association between ongoing thermal instability and respiratory morbidity remains unclear. 50,000 very low birth weight (VLBW) infants (< 1500 g) are born in the United States each year [1]. The most common complication of very premature birth is bronchopulmonary dysplasia (BPD) [2, 3], which occurs in approximately 50% of these infants [4, 5]. BPD occurs due to the arrest of normal lung development following premature birth. It is characterized by large, sparse alveoli and dysmorphic pulmonary vasculature, resulting in a decrease in surface area available for gas exchange [3, 6]. Many risk factors have been associated with the development of BPD; only a portion of infants with these shared risk factors develop this morbidity, complicating the prevention and treatment of disease [4]

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