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Air versus oxygen for resuscitation of infants at birth

  • Review
  • Intervention

Authors


Abstract

Background

100% oxygen is the commonly recommended gas for the resuscitation of infants at birth. There is growing evidence from both animal and human studies that room air is as effective as 100% oxygen and that 100% oxygen may have adverse effects on breathing physiology and cerebral circulation. There is also the theoretical risk of tissue damage due to free oxygen radicals when 100% oxygen is given. The use of room air has, therefore, been suggested as a safer and possibly more effective alternative.

Objectives

In newborn infants requiring resuscitation, does the use of room air reduce the incidence of death, neurological disability and short term morbidity when compared with the use of 100% oxygen?

Search methods

This included searches of the Oxford Database of Perinatal Trials, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2004) and MEDLINE PubMed 1966 to December 2003, and handsearches of reference lists of relevant articles and conference proceedings.

Selection criteria

All randomised and quasi-randomised studies comparing the use of room air or any other concentration of oxygen versus 100% oxygen in the resuscitation of infants at birth.

Data collection and analysis

Three authors assessed the methodological quality of eligible trials and extracted data independently. When appropriate, meta-analysis was conducted to provide a pooled estimate of effect. For categorical data the relative risk (RR), risk difference (RD) and number needed to treat (NNT) with 95% confidence intervals (CI) were calculated. Continuous data were analysed using weighted mean difference (WMD).

Main results

Five studies were identified which enrolled a total of 1302 infants. In two studies allocation was randomised and the caregivers were blinded to intervention group. In the other three studies, allocation was quasi-randomised and the caregivers were not blinded. Pooled analysis of the four trials reporting effect on death showed a significant reduction in the rate of death in the group resuscitated with room air [typical RR 0.71 (0.54, 0.94), typical RD -0.05 (-0.08, -0.01), NNT 20 (12, 100)]. There were no significant differences between the groups with respect to rates of grade 2 or 3 hypoxic ischaemic encephalopathy. One of the four trials reported a statistically significant difference in median 5 minute Apgar scores, favouring the group allocated to room air. However, the absolute difference between the medians was small and there were no significant differences in the median 10 minute Apgar scores in the three trials reporting this outcome.

One trial followed up a selected subgroup of survivors to 18-24 months. There were no significant differences in rates of adverse neurodevelopmental outcomes including cerebral palsy and failure to achieve various milestones; however, the proportion of eligible patients seen was less than 70%.

Analyses that were planned for this review, but not able to be carried out because of lack of published data, included a sub-analysis stratified by gestational age and assessments of the effect on bronchopulmonary dysplasia and retinopathy of prematurity.

Authors' conclusions

There is insufficient evidence at present on which to recommend a policy of using room air over 100% oxygen, or vice versa, for newborn resuscitation. A reduction in mortality has been seen in infants resuscitated with room air, and no evidence of harm has been demonstrated. However, the small number of identified studies and their methodologic limitations dictate caution in interpreting and applying these results. We note the use of back-up 100% oxygen in more than a quarter of infants randomised to room air. Therefore, on the basis of currently available evidence, if one chooses room air as the initial gas for resuscitation, supplementary oxygen should continue to be made available.

摘要

背景

嬰兒出生時使用空氣與氧氣復甦的比較

通常推薦100%氧氣用作嬰兒出生時復甦的氣體。無論動物還是人的研究,有越來越多的證據表明室內空氣與100%氧氣同樣有效,而100%氧氣可能對呼吸生理和大腦循環有不良影響。而且從理論上說,當給予100%氧氣時氧自由基有損傷組織的風險。因而,室內空氣已被建議為安全和可能更有效的替代品。

目標

對需要復甦的新生兒應用室內空氣,與應用100%氧氣相比,會降低死亡率、神經殘障和短期發病率嗎?

搜尋策略

檢索範圍包括牛津圍生兒試驗數據庫、Cochrane對照試驗中心註冊資料庫(CENTRAL,Cochrane圖書館,2004年第1 期)和MEDLINE、PubMed(1966年-2003年12月),並手工檢索了相關文章的參考文獻目錄和會議論文集。

選擇標準

所有對嬰兒出生復蘇時應用室內空氣或其它任何濃度氧氣與100%氧氣進行比較的隨機和半隨機研究。

資料收集與分析

三位作者獨立評估合格試驗的方法學質量並提取數據。在條件適合時,進行Meta分析提供匯總估計效應。對分類數據計算相對危險度(RR),風險差(RD)和需治療人數(NNT)及其95%可信區間(CI)。連續數據的分析使用加權均數差(WMD)。

主要結論

其中確定了五項研究共招收1302位嬰兒。在兩項研究的分配是隨機的且照顧者對干預組是blinded。在其他三項研究,分配是半隨機且照顧者是沒有blinded。匯總分析四項試驗報告了使用室內空氣做復甦對死亡率有顯著減少 [typical RR 0.71 (0.54, 0.94), typical RD −0.05 (−0.08, −0.01), NNT 20 (12, 100)]。就2級或3級缺氧缺血性腦病組沒有顯著差異。四個研究的其中一個,在五分鐘的Apgar分數中位數在室內空氣組較佳,但絕對值的差異很小,同時在另外三個報導10分鐘Apgar分數的研究中,均未顯出差異。一個試驗還追蹤了18 – 24個月倖存者次分組。在以下幾個神經發育不良後果都沒有顯著差異包括腦性麻痺,未能達到發展目標里程碑,符合條件的患者被追蹤比例低於70%。由於缺乏公佈的數據而無法進行的包括由胎齡分層次分析和評估對支氣管肺發育不良和早產兒視網膜病變的影響。。

作者結論

有關推薦哪種方針進行新生兒復甦,是室內空氣優於100%氧氣,還是相反,目前還沒有足夠的證據。在使用室內空氣復甦嬰兒中見到死亡率下降,沒有表明有害的證據。然而,由於找到的研究數太少以及這些研究的方法學局限性, 在解釋與應用這些結果時應該謹慎。我們注意到在隨機分配到室內空氣組的嬰兒中,超過四分之一返回使用100%氧氣。所以,根據目前可利用的證據,如果你選擇以室內空氣作為複甦的初始氣體的話,仍應做好補充氧氣的準備。

翻譯人

本摘要由臺中榮民總醫院薛榮華翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

概要尚未完成。

Plain language summary

Air versus oxygen for resuscitation of infants at birth

About 5 to 10% of infants need resuscitation at birth. Many experts recommend that these babies be resuscitated with 100% oxygen, but other experts think that normal room air is as good as or better than 100% oxygen. Too much oxygen can make breathing difficult for babies and can cause other problems such as problems with brain development, an eye condition (retinopathy of prematurity), and a lung condition (bronchopulmonary dysplasia). The authors of this Cochrane review questioned whether resuscitation with room air resulted in fewer deaths or disabilities than 100% oxygen. After searching the literature, they found five studies. There were a total of 1302 infants in these studies; 24% of them were premature. In the studies, fewer babies died when resuscitated with room air than with 100% oxygen. Many of the babies resuscitated with room air also got some oxygen as a supplement, making it difficult to compare the two groups. There were also other problems with the way the studies were carried out. The authors of the Cochrane review concluded that there is not enough evidence to recommend room air over 100% oxygen, or vice versa.

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