Oxygen targeting in preterm infants: a physiological interpretation

Outcomes of Two Trials of Oxygen-Saturation Targets in Preterm Infants

“…3,20 Pulse oximeters estimate arterial oxygen saturation within limits of accuracy, such that 1 standard deviation equals 3%. 10,16,21 Thus, an oxygensaturation value of 88% could reflect an arterial oxygen saturation between 85 and 91% in 68% of infants, but it may fall outside a range of 82 to 94% in up to 5% of infants. Variations in the location of the probe and the proportion of fetal hemoglobin may influence these limits 16 but should create no bias, because randomization tends to balance such factors evenly between groups.…”

“…10,16,21 Thus, an oxygensaturation value of 88% could reflect an arterial oxygen saturation between 85 and 91% in 68% of infants, but it may fall outside a range of 82 to 94% in up to 5% of infants. Variations in the location of the probe and the proportion of fetal hemoglobin may influence these limits 16 but should create no bias, because randomization tends to balance such factors evenly between groups. However, because pulse oximeters underestimate hypoxemia with progressively wider limits of accuracy as true oxygen-saturation values decrease from 93% to 80%, 21 substantially more infants in the lower-target group than in the higher-target group may have been exposed to values of partial pressure of arterial oxygen below the previously recommended levels, 22 with associated adverse effects.…”

“…Targeting an intermediate oxygen-saturation range, 16,28 such as 87 to 93%, versus a higher range is an untested practice that may increase mortality, because current oximeters permit increasingly disproportionate exposure to hypoxemia as oxygen saturation decreases to below 93%. 21 At present, the most rigorously evaluated evidence 29 for policy is that targeting an oxygen saturation of 91 to 95% is safer than targeting an oxygen saturation of 85 to 89%.…”

“…8,11 These significant differences in mortality were observed despite the lowerthan-planned separation in oxygen-saturation values found between the study groups. 15,16 After SUPPORT showed excess mortality among infants randomly assigned to lower oxygensaturation targets, 4 the BOOST trial investigators consulted their data and safety monitoring committees because of concerns about possible harm to infants in the lower-target group. 11 The results of a pooled interim safety analysis, conducted with the use of prespecified guidelines, 11 met the criteria of both protocols for stopping the study (Fig.…”

Oxygen Saturation Targets in Preterm Infants and Outcomes at 18–24 Months: A Systematic Review

“…The risk-of-bias category was graded as moderate due to a lack of separation in the target saturations. 31 A maximal separation of 6% was intended by using a masking algorithm that allowed gradual reduction to no separation outside of the target SpO 2 range. 31 -33 We acknowledge that quality of evidence is subjective and should not be penalized, if maintaining SpO 2 within a target range is exclusively due to clinical and practical factors.…”