Thoracoabdominal Asynchrony Is Not Associated with Oxyhemoglobin Saturation in Recovering Premature Infants.

BACKGROUND

Recovering premature infants are at risk for hypoxemia and lack of synchrony between their rib cage and abdomen due to airflow obstruction and poor respiratory compliance. Thoracoabdominal asynchrony (TAA) is a useful marker of resistive and elastic lung properties. Whether TAA predicts oxygenation is unknown.

OBJECTIVES

We investigated oxyhemoglobin saturation (SpO2%) and TAA (phase angle, φ) in preterm infants with/without high-humidity nasal cannula (HHNC).

METHODS

A cross-sectional observational study was conducted in 92 infants at 32 weeks' postmenstrual age. We measured SpO2% with pulse oximetry and TAA with φ via respiratory inductance plethysmography in infants (mean gestational age: 26.4 + 1.3 weeks) who required room air (n = 18) or HHNC with/without supplemental oxygen (1-5 liters per minute, FiO2 0.21-0.33, n = 74). We calculated median SpO2% from 24.7 + 10.0 min of quiet sleep and median φ from up to 60 breaths.

RESULTS

Infants breathing room air alone had marked TAA (φ = 83.6 + 32.9°, range: 10.9-148.5) as did those receiving varying degrees of ventilatory and oxygen support via HHNC (range of group means, φ = 47.0-90.0°). Infants breathing room air had statically greater median SpO2% than those receiving support (96.3 + 0.6% vs. 91.3 + 0.6%; ANOVA p = 0.001). SpO2% was not associated with TAA in either group (r2 = 0.09).

CONCLUSION

Recovering premature infants exhibited TAA regardless of need for ventilatory support and supplemental oxygen. TAA was not associated with SpO2% in either group. Maintenance of SpO2% does not require correction of TAA.