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Randomised crossover trial comparing algorithms and averaging times for automatic oxygen control in preterm infants
Christoph E Schwarz1,2, Karen B Kreutzer3, Lukas Langanky1
1Department of Neonatology, University Children's Hospital Tübingen, Tübingen, Baden-Württemberg, Germany.
Insights
Single programmed oxygen control (SPOC) algorithms significantly improve oxygen saturation targeting in preterm infants compared to routine manual control. The revised SPOC algorithm, even with an upper oxygen limit, demonstrated superior performance in maintaining target saturation levels.
Area of Science:
- Neonatal Medicine
- Respiratory Physiology
- Medical Technology
Background:
- Single programmed oxygen control (SPOC) using pulse oximetry (SpO2) saturation improves time within target saturation ranges for preterm infants.
- Previous SPOC algorithms lacked an upper fraction of inspired oxygen (FiO2) limit, potentially leading to suboptimal control.
- Optimizing SpO2 control is crucial for managing respiratory support in vulnerable preterm neonates.
Purpose of the Study:
- To evaluate if a revised SPOC algorithm (SPOCnew) with an upper FiO2 limit improves the percentage of time preterm infants spend within the SpO2 target range (Target%) compared to routine manual control (RMC) and a previous SPOC algorithm (SPOCold).
- To assess the impact of different SpO2 averaging times (2s and 8s) on SpO2 control during SPOC periods.
Main Methods:
- A randomized controlled crossover study was conducted in a tertiary neonatal intensive care unit.
- Twenty-four preterm infants on non-invasive respiratory support received 12-hour periods of SPOCnew and SPOCold, each with 6 hours of 2s and 8s averaging times, compared against 6-hour periods of RMC.
- The primary outcome measure was the percentage of time SpO2 remained within the predefined target range (Target%).
Main Results:
- Both SPOC algorithms (SPOCold and SPOCnew) resulted in a significantly higher Target% compared to RMC, irrespective of the averaging time used.
- SPOCnew achieved a Target% of 70% (2s averaging) and 72% (8s averaging), while SPOCold achieved 69% (2s) and 71% (8s), compared to 56% for RMC.
- The averaging time of the pulse oximeter did not significantly alter the effectiveness of SpO2 control under SPOC.
Conclusions:
- SPOC algorithms, including the revised version with an upper FiO2 limit, are superior to RMC in maintaining target SpO2 levels in preterm infants.
- The SPOCnew algorithm effectively controls SpO2 within the target range, even when an upper limit for FiO2 is imposed.
- The findings support the use of SPOC for optimizing oxygen therapy in neonatal intensive care, with averaging time having minimal impact.
Objective:
Automatic control (SPOC) of the fraction of inspired oxygen (FiO2), based on continuous analysis of pulse oximeter saturation (SpO2), improves the proportion of time preterm infants spend within a specified SpO2-target range (Target%). We evaluated if a revised SPOC algorithm (SPOCnew, including an upper limit for FiO2) compared to both routine manual control (RMC) and the previously tested algorithm (SPOCold, unrestricted maximum FiO2) increases Target%, and evaluated the effect of the pulse oximeter's averaging time on controlling the SpO2 signal during SPOC periods.
Design:
Unblinded, randomised controlled crossover study comparing 2 SPOC algorithms and 2 SpO2 averaging times in random order: 12 hours SPOCnew and 12 hours SPOCold (averaging time 2 s or 8 s for 6 hours each) were compared with 6-hour RMC. A generated list of random numbers was used for allocation sequence.
Setting:
University-affiliated tertiary neonatal intensive care unit, Germany PATIENTS: Twenty-four infants on non-invasive respiratory support with FiO2 >0.21 were analysed (median gestational age at birth, birth weight and age at randomisation were 25.3 weeks, 585 g and 30 days).
Main Outcome Measure:
Target%.
Results:
Mean (SD) [95% CI] Target% was 56% (9) [52, 59] for RMC versus 69% (9) [65, 72] for SPOCold_2s, 70% (7) [67, 73] for SPOCnew_2s, 71% (8) [68, 74] for SPOCold_8s and 72% (8) [69, 75] for SPOCnew_8s.
Conclusions:
Irrespective of SpO2-averaging time, Target% was higher with both SPOC algorithms compared to RMC. Despite limiting the maximum FiO2, SPOCnew remained significantly better at maintaining SpO2 within target range compared to RMC.
Trial Registration:
NCT03785899.
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