Randomized controlled trial of low vs high oxygen during neonatal anesthesia: Oxygenation, feasibility, and oxidative stress

Abstract

Background: To reduce risk for intermittent hypoxia a high fraction of inspired oxygen is routinely used during anesthesia induction. This differs from the cautious dosing of oxygen during neonatal resuscitation and intensive care and may result in significant hyperoxia. Aim:In a randomized controlled trial, we evaluated oxygenation during general anesthesia with a low (23%) vs a high (80% during induction and recovery, and 40% during maintenance) fraction of inspired oxygen, in newborn infants undergoing surgery.Method: Thirty-five newborn infants with postconceptional age of 35-44 weeks were included (17 infants in low and 18 in high oxygen group). Oxygenation was monitored by transcutaneous partial pressure of oxygen, pulse oximetry, and cerebral oxygenation. Predefined SpO2 safety targets dictated when to increase inspired oxygen.Results: At start of anesthesia, oxygenation was similar in both groups. Throughout anesthesia, the high oxygen group displayed significant hyperoxia with higher (difference−20.3 kPa, 95% confidence interval (CI)-28.4 to 12.2, p < .001) transcutaneous partial pressure of oxygen values than the low oxygen group. While SpO2 in the low oxygen group was lower (difference − 5.8%, 95% CI -9.3 to -2.4, p < .001) during anesthesia, none of the infants spent enough time below SpO 2 safety targets to mandate supplemental oxygen, and cerebral oxygenation was within the normal range and not statistically different between the groups. Analysis of the oxidative stress biomarker urinary F 2 -Isoprostane revealed no differences between the low and high oxygen group. Conclusion:We conclude that in healthy newborn infants, use of low oxygen during general anesthesia was feasible, while the prevailing practice of using high levels of inspired oxygen resulted in significant hyperoxia. The trade-off between careful dosing of oxygen and risks of hypo-and hyperoxia in neonatal anesthesia should be further examined.

What is your optimal target of oxygen during general anesthesia in pediatric patients?

“…In a recent study of healthy children divided into hypoxia and hyperoxia groups, transcutaneous oxygen and SpO 2 measured by pulse oximetry were significantly lower in the hypoxia group; however, regional cerebral oxygen saturation (rSO 2 ) showed no difference between the two groups. Additional research is needed to determine whether hyperoxia is as dangerous as hypoxia, but the rSO 2 value decreased regardless of FiO 2 in this study, and it seems to reflect the pharmacological effect of an anesthetic induction agent, which additional research is needed [53].…”

When does the oxygen cease to be a remedy?

“…U postoperativnom periodu, zbog centralne hipoventilacije i apneje kod dece, češće nastaje desaturacija 35 . Karlson i saradnici su kroz randomizovano kliničko ispitivanje, pokazali da je bezbedno kod zdrave terminske novorođenčadi, tokom opšte anestezije, koristiti 21% kiseonik 36 . Terapijski pristup kod prevremeno rođene dece podrazumeva dugotrajnu upotrebu kiseonika, što vodi hiperreaktivnosti disajnih puteva u prvim godinama života, bronhopulmonalnoj displaziji i razvoju astme.…”

Low vs high oxygen during neonatal anesthesia

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We read with great enthusiasm the exemplary article by Lee et al 1 for which the authors should be commended. One question that arises from the authors' findings is whether these results are applicable to bidirectional cavopulmonary shunt and Fontan patients who have not recently undergone these procedures (unlike the study cohort who were immediately postoperative).

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