Mechanically ventilated premature babies have sex differences in specific elastance: A pilot study

Abstract

Objectives:A pilot study to compare pulmonary mechanics in a NICU cohort, specifically, comparing lung elastance between male and female infants in the neonatal ICU (NICU).Hypothesis: Anecdotally, male infants are harder to ventilate than females. We hypothesise that males have higher model-based elastance (converse: lower specific compliance) compared to females, reflecting underlying stiffer lungs. Study design:A clinically validated, single compartment model is used to identify specific elastance (inverse of specific compliance) and resistance for each breath. Specific elastance accounts for weight differences when comparing male and female infants. Relative percent breath-to-breath variability (%ΔE) in specific elastance is also compared. Level of asynchrony was determined. Patient-subject selection: 10 invasively mechanically ventilated patients from ChristchurchWomen's Hospital.Methodology: Airway pressure and flow data from 10 invasive MV infants from Christchurch Women's Hospital Neonatal Intensive Care Unit, New Zealand was prospectively recorded under standard MV care. Model-based specific elastance and resistance are identified for each breath, as well as relative percent breath-to-breath variability (%ΔE) in specific elastance. Results: Male infants overall had higher specific elastance compared to females infants (p ≤ 0.01), with median [interquartile range (IQR)] for males of 1.91[1.33-2.48]cmH2O.kg/ml compared to 1.31[0.86-2.02]cmH2O.kg/ml in females. Male infants had lower variability with %ΔE of -0.03[-7.56 -8.01]% versus female infants of -0.59[12.56 -12.86]%. Males had 14.75% asynchronous breaths whereas females had 17.54%.Conclusion: Overall, males had higher specific elastance and correspondingly lower breathto-breath variability. These results indicate male and female infants may require different MV settings, modes and monitoring.

Stochastic Modelling of Respiratory System Elastance for Mechanically Ventilated Respiratory Failure Patients

“… 41 , 63 Further studies could include assessing interval to interval variability in sub-cohorts, where similar analyses in glycemic control and MV have found differences between sexes that can impact care. 24 , 36 , 62 …”

2020 year in review: Neonatal pulmonology

“…Pulmonary function testing is used in newborns to provide physiological understanding and to guide therapy. Kim et al 1 used a single‐compartment model to estimate respiratory system elastance in 10 mechanically ventilated newborns. Their observation that male infants had increased elastance (reduced compliance) may reflect delayed alveolar development, but the variability of the measurements was quite high, and the study sample was quite modest 1 .…”

“…Kim et al 1 used a single‐compartment model to estimate respiratory system elastance in 10 mechanically ventilated newborns. Their observation that male infants had increased elastance (reduced compliance) may reflect delayed alveolar development, but the variability of the measurements was quite high, and the study sample was quite modest 1 . Veneroni et al 2 tested whether or not sustained inflation at birth (vs. nCPAP) in prematures in mild respiratory distress would durably alter mechanics measured by forced oscillation, finding, as in the study by Kim et al, 1 that the variability of measurements is quite high, with no discernible difference between the two strategies.…”

Pediatric Pulmonology Year in Review 2020: Physiology

“…Sex differences in lung function and structure are well known, but studies of sex differences in lung mechanics of preterm neonates are lacking. Kim, et al measured airway pressure and flow in male and female neonates requiring mechanical ventilation for neonatal respiratory distress syndrome, and then used these data to generate a single compartment model to calculate specific elastance (E S ) [26]. Male infants had higher E S compared to female infants of matched gestational age and less breath-to-breath variability in E S .…”