Frequency and duration of extreme hypoxemic and hyperoxemic episodes during manual and automatic oxygen control in preterm infants: a retrospective cohort analysis from randomized studies

Abstract

Objective Neonatal exposure to episodic hypoxemia and hyperoxemia is highly relevant to outcomes. Our goal was to investigate the differences in the frequency and duration of extreme low and high SpO2 episodes between automated and manual inspired oxygen control. Design Post-hoc analysis of a cohort from prospective randomized cross-over studies. Setting Seven tertiary care neonatal intensive care units. Patients Fifty-eight very preterm neonates (32 or less weeks PMA) receiving respiratory support and supplemental oxygen participating in an automated versus manual oxygen control cross-over trial. Main measures Extreme hypoxemia was defined as a SpO2 < 80%, extreme hyperoxemia as a SpO2 > 98%. Episode duration was categorized as < 5 seconds, between 5 to < 30 seconds, 30 to < 60 seconds, 60 to < 120 seconds, and 120 seconds or longer. Results The infants were of a median postmenstrual age of 29 (28-31) weeks, receiving a median FiO2 of 0.28 (0.25-0.32) with mostly receiving non-invasive respiratory support (83%). While most of the episodes were less than 30 seconds, longer episodes had a marked effect on total time exposure to extremes. The time differences in each of the three longest durations episodes (30, 60, and 120 seconds) were significantly less during automated than during manual control (p < 0.001). Nearly two-third of the reduction of total time spent at the extremes between automated and manual control (3.8 to 2.1% for < 80% SpO2 and 3.0 to 1.6% for > 98% SpO2) was seen in the episodes of at least 60 seconds. Conclusions This study shows that the majority of episodes preterm infants spent in SpO2 extremes are of short duration regardless of manual or automated control. However, the infrequent longer episodes not only contribute the most to the total exposure, but also their reduction in frequency to the improvement associated with automated control.

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

“…In our study, the reduction in total percentage of time in severe hyperoxaemia (SpO 2 >98%) was largely due to a significant reduction in percentage of prolonged episodes of SpO 2 >98%. This has been reported with another A-FiO 2 system 15. Hyperoxaemia when in supplemental oxygen is largely preventable by rigorous manual adjustments of FiO 2 .…”

Automated oxygen control for routine use in the NICU—Are we there?

“…The time spent in hypoxaemia (<80% SpO 2 ) was about 50% lower in the automated oxygencontrolgroupthanmanualgroup.Thetimespentinhyperoxaemia(>98%SpO 2 )wasreducedbyabout66%. 10 Abdo et al's systematic review of 13 studies confirmed these findings.Automatedoxygencontrolincreasedthetimespentwithin theSpO 2 targetsofboth85%-96%and90%-95%.Inaddition,time inhypoxaemia(SpO 2 < 80%)decreasedinthepredeterminedtarget rangesof85%-96%and90%-95%.Theautomatedcontrolsystem also reduced the time in hyperoxia (>98%) at an intended target range of 90%-95% SpO 2 . They concluded that automated oxygen delivery was rapid and effective in controlling the infants' oxygen saturation.…”

“…The time spent in hypoxaemia (<80% SpO 2 ) was about 50% lower in the automated oxygen control group than manual group. The time spent in hyperoxaemia (>98% SpO 2 ) was reduced by about 66% 10 …”