Tidal volume measurements in newborns using respiratory inductive plethysmography

Area of Science:

• Neonatal Physiology
• Respiratory Monitoring
• Medical Instrumentation

Background:

• Respiratory inductive plethysmography (RIP) is a noninvasive method for monitoring breathing patterns in adults.
• Previous calibration methods for RIP in infants faced technical challenges, limiting its use in this population.
• Qualitative diagnostic calibration (QDC) offers accurate tidal volume calibration in adults during natural breathing.

Purpose of the Study:

• To assess the accuracy of RIP calibrated with QDC for measuring tidal volume (VT) in healthy full-term newborns.
• To compare RIP-measured VT with pneumotachograph (PNT)-measured VT in supine and prone infant positions.
• To evaluate the influence of sleep state (active vs. quiet) on RIP calibration accuracy.

Main Methods:

• RIP was calibrated using the QDC method in the supine posture.
• Tidal volume was measured simultaneously using RIP and a face mask-pneumotachograph (PNT) in 21 healthy newborns.
• Measurements were taken in both supine and prone postures during active and quiet sleep.

Main Results:

• Mean tidal volumes were 19 ml in the supine and 25 ml in the prone postures.
• Weighted mean differences between RIP (VT) and PNT (VT) were small and statistically insignificant in both postures.
• Calibration accuracy was not affected by sleep state or the presence of thoracoabdominal incoordination.

Conclusions:

• RIP calibrated with QDC in the supine posture provides clinically acceptable VT measurements in full-term infants.
• This calibration method is effective for monitoring infant breathing in both supine and prone positions.
• QDC offers a practical and accurate solution for RIP calibration in neonatal respiratory monitoring.