Summary: Randomised control trial of oxygen assist module* in preterm infants on high-flow nasal cannula support.

Topic: Automated Oxygen Control

Nair  V, Kannan Loganathan P, Lal MK, et al. Randomised control trial of oxygen assist module* in preterm infants on high-flow nasal cannula support. Archives of Disease in Childhood – Fetal and Neonatal Edition Published Online First: 14 July 2023. doi: 10.1136/archdischild-2023-325661 

  • The oxygen assist module is not currently available for sale in the U.S. 

Nair and colleagues conducted a parallel-arm, randomized, controlled trial (RCT) to evaluate the efficacy of automatic oxygen control (A-FiO2) using the Oxygen Assist Module (OAM; Vapotherm, Exeter, NH) versus manual intervention (M-FiO2) in reducing the extremes of oxygen saturations (SpO2<80% and SpO2>98%) in preterm infants <33 weeks of age receiving high velocity therapy respiratory support. The study found the percentage of time spent in SpO2<80% and SpO2>98% was significantly lower in the OAM automated control arm compared with manual control. This significant reduction in extremes of SpO2 corresponded with a reduction of number and percentage of time during prolonged episodes.  

In this study, 60 infants were randomized equally to either A-FiO2 or the M-FiO2. Their baseline characteristics were comparable. They spent a median of 5.3 (IQR: 2.0 to 8.4) and 6.5 (IQR: 2.9 to 13.7) days in the study, A-FiO2 and M-FiO2, respectively. The percentage of time spent in SpO2<80% (median of 0.4% (0.1% to 0.8%) vs 1.6% (0.6% to 2.6%), p=0.002) and >98% (median 0.2% (0.1% to 0.9%) vs 1.9% (0.7% to 4%), p<0.001) were significantly lower in A-FiO2 compared with M-FiO2. The difference in median percentage of time in target range between the two arms was 26% (81% (74% to 93%) in A-FiO2 vs 55% (48% to 72%) in M-FiO2). 

Table 1: Outcomes 

Primary Endpoints 
(Median IQR) 
A-FiO2 (OAM) M-FIO2 P value
Proportion of time in SpO2<80% (%) 0.4 (0.1 to 0.8)1.6 (0.6 to 2.6)0.002 
Proportion of time in SpO2>98% (%) 0.2 (0.1 to 0.9) 1.9 (0.7 to 4)<0.001 
Secondary Endpoints 
(Median IQR) 
Proportion of time in target range (%) 
including time SpO2>95% on room air 
81 (74 to 93) 55 (48 to 72)<0.001 

The authors suggest one study limitation related to the use of two sensors and monitors for SpO2 (for the A-FiO2 arm, the automated FiO2 adjustments were based on SpO2 reading on OAM, versus use of the overhead patient monitor for the M-FiO2 arm). This study did not include the data from overhead monitors to document the differences in SpO2 profile from two devices. The authors posit that given the low occurrence of differences on clinical observation; this may suggest no significant bias. The researchers also did not collect data on the number of times the SpO2 probes were re-situated. However, it was noted that the two SpO2 readings on the hourly observation chart did not show major discrepancies. Finally, this study was not a blinded study. 

The authors concluded that in this longitudinal parallel-arm RCT, there was a statistically significant reduction in the exposure to severe hypoxemia (SpO2<80%) and severe hyperoxemia (SpO2>98%) with the oxygen assist module controller(A-FiO2) when compared with the manual control.  

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