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Hypoxemia Episodes during Day and Night and Their Impact on Oxygen Saturation Targeting in Mechanically Ventilated
Deepak Jain1, Carmen D'Ugard, Jose Bello
1Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine, Miami, FL, USA.
Insights
Hypoxemia episodes (HE) were less frequent at night in ventilated preterm infants. Reduced handling and sensory stimulation during nighttime likely contribute to fewer HE and better oxygen saturation targeting.
Area of Science:
- Neonatal Medicine
- Pediatric Critical Care
- Respiratory Physiology
Background:
- Frequent hypoxemia episodes (HE) in ventilated preterm infants impede achieving oxygen saturation (SpO2) targets.
- HE may elevate risks for retinopathy of prematurity and neurodevelopmental disabilities.
- Limited data exist on diurnal variations in HE and SpO2 targeting.
Purpose of the Study:
- To investigate the differences between day and night regarding the frequency and severity of HE.
- To assess the achievement of target SpO2 ranges during daytime versus nighttime.
- To analyze diurnal patterns in SpO2 control for ventilated preterm infants.
Main Methods:
- Twenty-four mechanically ventilated preterm infants experiencing frequent HE (SpO2 <75%) were monitored over 24 hours.
- Fraction of inspired oxygen (FiO2), SpO2, and ventilator parameters were continuously recorded.
- Daytime (9 a.m. - 5 p.m.) data were compared with nighttime (9 p.m. - 5 a.m.) data.
Main Results:
- Fewer severe HE (SpO2 <75%, ≥20s or ≥60s) and mild HE (SpO2 <85%, ≥20s) occurred during the night.
- The proportion of time spent in severe hypoxemia (SpO2 <75%) was lower at night.
- Time spent in hyperoxemia (SpO2 >95%) was greater during the night; mean FiO2 remained consistent.
Conclusions:
- Nighttime is associated with a reduced frequency of hypoxemia episodes in ventilated preterm infants.
- Decreased handling and sensory stimulation at night may explain the lower HE frequency.
- Increased hyperoxemia at night might result from greater tolerance of higher SpO2 levels with less active FiO2 weaning.
Background:
Hypoxemia episodes (HE) occur frequently in ventilated preterm infants and hinder the achievement of arterial oxygen saturation (SpO2) targets. These episodes may increase the risk for retinopathy of prematurity and neurodevelopmental disability. There are no data on the variation in HE and SpO2 targeting between day and night.
Objective:
The aim of this study was to evaluate the difference between day and night on the frequency and severity of HE and achievement of SpO2 targets.
Methods:
Twenty-four mechanically ventilated preterm infants with ≥4 episodes of SpO2 <75% over an 8-h period were enrolled. The fraction of inspired oxygen (FiO2), SpO2, and ventilator parameters were recorded over 24 h. Data from the day (9 a.m. to 5 p.m.) were compared to the night (9 p.m. to 5 a.m.) for the frequency of HE and proportion of time within and outside the target SpO2 range (90-95%).
Results:
The frequency of severe HE (SpO2 <75, ≥20 s) and prolonged severe HE (SpO2 <75, ≥60 s) was lower during the night compared to the day (1.6 ± 1.0 vs. 2.4 ± 1.3 episodes/h, p = 0.008, and 0.53 ± 0.35 vs. 0.90 ± 0.54 episodes/h, p = 0.018). There was no difference in mean episode duration. The frequency and duration of mild HE (SpO2 <85, ≥20 s) were lower during the night compared to the day (5.9 ± 2.7 vs. 7.1 ± 2.5 episodes/h, p = 0.003, and 72 ± 15 vs. 87 ± 25 s, p = 0.01, respectively). The proportion of time in severe hypoxemia (SpO2 <75%) was smaller, whereas time in hyperoxemia (SpO2 >95%) was greater, during the night compared to the day. The mean FiO2 did not differ between day and night.
Conclusion:
In this group of infants with frequent HE, nighttime was associated with fewer episodes when compared to daytime. This is likely due to less handling and sensory stimulation during the night. The increase in time spent with hyperoxemia during the night is likely to be due to more tolerance of high SpO2 with less proactive weaning of FiO2.
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