Accuracy of currently available neonatal respiratory function monitors for neonatal resuscitation

Abstract

This study aimed to test the accuracy in volume measurements of three available respiratory function monitors (RFMs) for neonatal resuscitation and the effect of changing gas conditions. The Florian, New Life Box Neo-RSD (NLB Neo-RSD) and NICO RFM were tested on accuracy with volumes of 10 and 20 mL and on changes in volume measurements under changing gas conditions (oxygen level 21-100 % and from cold dry air (24 ± 2 °C) to heated humidified air (37 °C). Volume differences >10 % were considered clinically relevant. We found that the mean (SD) volume difference was clinically acceptable for all devices (10, 20 mL): Florian (+8.4 (1.2)%, +8.4 (0.5)%); NLB Neo-RSD (+5.8 (1.1)%, +4.3 (1.4)%); and NICO (-8.2 (0.9)%, -8.7 (0.8)%). Changing from cold dry to heated humidified air increased the volume difference using the Florian (cold dry air, heated humidified air (+5.2 (1.2)%, +12.2 (0.9)%) but not NLB Neo-RSD (+2.0(1.6)%, +3.4(2.8)%) and NICO (-2.3 % (0.8), +0.1 (0.6)%). Similarly, when using heated humidified air, increasing oxygen enlarged increased the volume difference using the Florian (oxygen 21 %, 100 %: +12.2(1.0)%, +19.8(1.1)%), but not NLB Neo-RSD (+0.2(1.9)%, +1.1(2.8)%) and NICO (-5.6(0.9)%, -3.7(0.9)%). Clinically relevant changes occurred when changing both gas conditions (Florian +25.7(1.7)%; NLB Neo-RSD +3.8(2.4)%; NICO -5.7(1.4)%).

Conclusion: The available RFMs demonstrated clinically acceptable deviations in volume measurements, except for the Florian when changing gas conditions.

What is known: •Respiratory function monitors (RFMs) are increasingly used for volume measurements during respiratory support of infants at birth. •During respiratory support at birth, gas conditions can change quickly, which can influence the volume measurements. What is new: •The available RFMs have clinically acceptable deviations when measuring the accuracy of volume measurements. •The RFM using a hot wire anemometer demonstrated clinically relevant deviations in volume measurements when changing the gas conditions. These deviations have to be taken into account when interpreting the volumes directly at birth.

Keywords: Neonatology; Respiratory function monitor; Resuscitation; Tidal volume.

Fig. 1

The experimental set-up to determine the accuracy of the three RFMs

Fig. 2

The experimental set-up to test the deviation under different gas conditions