Intervention Review

Permissive hypercapnia for the prevention of morbidity and mortality in mechanically ventilated newborn infants

  1. Paul G Woodgate1,*,
  2. Mark W Davies2

Editorial Group: Cochrane Neonatal Group

Published Online: 23 APR 2001

Assessed as up-to-date: 9 FEB 2001

DOI: 10.1002/14651858.CD002061


How to Cite

Woodgate PG, Davies MW. Permissive hypercapnia for the prevention of morbidity and mortality in mechanically ventilated newborn infants. Cochrane Database of Systematic Reviews 2001, Issue 2. Art. No.: CD002061. DOI: 10.1002/14651858.CD002061.

Author Information

  1. 1

    Mater Mothers' Hospital, Dept of Neonatology, South Brisbane, Queensland, Australia

  2. 2

    Royal Brisbane and Women's Hospital, Grantley Stable Neonatal Unit, Brisbane, Queensland, Australia

*Paul G Woodgate, Dept of Neonatology, Mater Mothers' Hospital, Raymond Terrace, South Brisbane, Queensland, 4101, Australia. Paul.Woodgate@mater.org.au.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 23 APR 2001

SEARCH

 

Abstract

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Background

Experimental animal data and uncontrolled, observational studies in human infants have suggested that hyperventilation and hypocapnia may be associated with increased pulmonary and neurodevelopmental morbidity. Protective ventilatory strategies allowing higher levels of arterial CO2 (permissive hypercapnia) are now widely used in adult critical care. The aggressive pursuit of normocapnia in ventilated newborn infants may contribute to the already present burden of lung disease. However, the safe or ideal range for PCO2 in this vulnerable population has not been established.

Objectives

To assess whether, in mechanically ventilated neonates, a strategy of permissive hypercapnia improves short and long term outcomes (esp. mortality, duration of respiratory support, incidence of chronic lung disease and neurodevelopmental outcome).

Search methods

Standard strategies of the Cochrane Neonatal Review Group were used. Searches were made of the Oxford Database of Perinatal Trials, MEDLINE, CINAHL, and Current Contents. Searches were also made of previous reviews including cross-referencing, abstracts, and conference and symposia proceedings published in Pediatric Research.

Selection criteria

All randomised controlled trials in which a strategy of permissive hypercapnia was compared with conventional strategies aimed at achieving normocapnia (or lower levels of hypercapnia) in newborn infants who are mechanically ventilated were eligible.

Data collection and analysis

Standard methods of the Cochrane Neonatal Review Group were used. Trials identified by the search strategy were independently reviewed by each author and assessed for eligibility and trial quality. Data were extracted separately. Differences were compared and resolved. Additional information was requested from trial authors. Only published data were available for review. Results are expressed as relative risk and risk difference for dichotomous outcomes, and weighted mean difference for continuous variables.

Main results

Two trials involving 269 newborn infants were included. Meta-analysis of combined data was possible for three outcomes. There was no evidence that permissive hypercapnia reduced the incidence of death or chronic lung disease at 36 weeks (RR 0.94, 95% CI 0.78, 1.15), intraventricular haemorrhage grade 3 or 4 (RR 0.84, 95% CI 0.54, 1.31) or periventricular leukomalacia (RR 1.02, 95% CI 0.49, 2.12). There were no differences in any other reported outcomes when the strategy of permissive hypercapnia/minimal ventilation was compared to routine ventilation in newborn infants. Long term neurodevelopmental outcomes were not reported. One trial reported that permissive hypercapnia reduced the incidence of chronic lung disease in the 501 to 750 gram subgroup.

Authors' conclusions

This review does not demonstrate any significant overall benefit of a permissive hypercapnia/minimal ventilation strategy compared to a routine ventilation strategy. At present, therefore, these ventilation strategies cannot be recommended to reduce mortality, or pulmonary and neurodevelopmental morbidity. Ventilatory strategies which target high levels of PCO2 (> 55 mmHg) should only be undertaken in the context of well-designed controlled clinical trials. These trials should aim to establish the safe, or ideal, range for CO2 in ventilated newborns, and examine the role of protective ventilatory techniques in achieving this target.

 

Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

Permissive hypercapnia for the prevention of morbidity and mortality in mechanically ventilated newborn infants

Not enough evidence to show the effect of permissive hypercapnia compared to routine ventilation for preterm babies needing mechanical ventilation. Sometimes preterm babies need help from a machine to breathe (mechanical ventilation). Very low carbon dioxide levels, produced by mechanical ventilation of the lungs are thought to cause lung damage and developmental problems. Hypercapnia (increasing the levels of carbon dioxide in the blood) is used for adults in critical care. It may also help newborn babies, especially those with lung damage on mechanical ventilation. The review of trials found there was not enough evidence to show the effect of permissive hypercania compared to routine ventilation for preterm babies. More research is needed.

 

摘要

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. 摘要

背景

在使用機械式呼吸器的新生兒,以容許較高之二氧化碳之方式來預防罹病與死亡的情況

在實驗性動物資料,以及未採取對照的人體嬰兒之觀察性研究,都認為過度換氣與血液之二氧化碳濃度過低可能與肺部與神經發展方面的罹病情況增加有關。採取保護性措施的呼吸器使用方法,來允許動脈中的二氧化碳維持在較高之濃度(容許較高之二氧化碳),目前已經廣泛地被使用在成年人的重症照護上。在使用呼吸器的新生兒,若是要積極地追求二氧化碳的濃度正常,可能會讓原本就已經存在的肺部疾病負擔加重。然而,在這易受傷害的族群中,卻還沒有針對二氧化碳的分壓(PCO2)而建立起安全或是理想的範圍。

目標

在實驗性動物資料,以及未採取對照的人體嬰兒之觀察性研究,都認為過度換氣與血液之二氧化碳濃度過低可能與肺部與神經發展方面的罹病情況增加有關。採取保護性措施的呼吸器使用方法,來允許動脈中的二氧化碳維持在較高之濃度(容許較高之二氧化碳),目前已經廣泛地被使用在成年人的重症照護上。在使用呼吸器的新生兒,若是要積極地追求二氧化碳的濃度正常,可能會讓原本就已經存在的肺部疾病負擔加重。然而,在這易受傷害的族群中,卻還沒有針對二氧化碳的分壓(PCO2)而建立起安全或是理想的範圍。

搜尋策略

在使用機械式呼吸器的新生兒身上,要評估容許較高之二氧化碳的策略是否能夠改善短期與長期的預後(尤其是針對死亡率、呼吸輔助的時間長度、發生慢性肺部疾病的比例,以及神經發展方面的預後)。

選擇標準

在接受了機械式呼吸器的新生兒身上,將容許較高之二氧化碳的策略與傳統的策略(達到正常或是只有些微高之二氧化碳濃度)進行了比較,這些試驗都是合格的。

資料收集與分析

我們使用的是the Cochrane Neonatal Review Group的標準方法。這些由研究策略所確認出來的試驗,都是經由每1位作者獨立地檢查過,並且針對合格度與試驗的品質來加以評估。這些資料都是分開進行擷取的。差異會拿來比較,然後予以解決。我們還跟試驗的作者們索取過更多的資訊。只有已經發表過的資料,才能夠被用於回顧當中。這些結果在針對二元性的資料方面,是用相對風險(RR)與風險差異(RD)的方式來表達,在針對連續性的變異數方面,則是用加權平均差(WMD)來表達。

主要結論

當中共收集了包含269名新生嬰兒在內的2份試驗。可將資料合併起來進行統合分析之預後有3項:死亡或是在36週時之慢性肺部疾病的發生率降低(R .94,95% CI 0.78,1.15)、第3或第4集的腦室內出血的情形減少(R .84,95% CI 0.54,1.31),或是周腦室白質軟化症的情況減少(R .02,95% CI 0.49,2.12)等3方面,並沒有證據顯示容許較高之二氧化碳有這樣的功效。將容許較高之二氧化碳/用極低之換氣來調整呼吸器之使用這樣的策略與傳統性的呼吸器之使用比較起來,在其他項的預後當中,也並沒有顯示出任何差異存在。針對長期的神經發展預後,則沒有人提出過報告。有1份試驗報告在501到750公克的次群組當中,容許較高之二氧化碳可以讓慢性肺部疾病的發生率下降。

作者結論

本篇回顧顯示,跟傳統性的呼吸氣之使用策略比較起來,容許較高之二氧化碳/用極低之換氣來調整呼吸器之使用的策略並沒有帶來任何明顯的整體優勢。因此,在目前的階段,這些呼吸器之使用策略都沒有辦法可以更降低死亡機率、或是減少肺部與神經發展方面的罹病情況。呼吸器之使用策略來讓PCO2維持在高濃度(PCO2 > 55 mmHg),只能夠在經過妥善設計、加以管控之臨床試驗的背景之中進行。關於這些試驗應該要在使用呼吸器的新生兒身上,以建立起安全,或是理想的二氧化碳範圍為目標,並且在追求這樣的目標時,還要檢驗此種以保護作用為目的的。呼吸器之使用技術所扮演的角色。

翻譯人

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

總結

對於需要機械式呼吸器的早產兒而言,跟使用傳統性的呼吸器策略比較起來,並沒有足夠的證據能夠指出容許較高之二氧化碳所帶來好的的影響。有時候,早產兒們需要機器的幫助才能夠呼吸(機械式呼吸器)。人們認為,由肺部的機械式呼吸器所導致之非常低濃度的二氧化碳,會對肺部造成傷害,並引起神經發展方面的問題。對於身處於重症照護中的成年人,會使用高濃度的二氧化碳(增加血液中的二氧化碳濃度)。這樣的方法或許也能夠幫助剛出生的嬰兒們,尤其是那些因為機械式呼吸器而產生肺部傷害者。本篇試驗回顧發現,對於早產兒而言,並沒有足夠的證據可以顯示出容許較高之二氧化碳跟傳統性之呼吸器比較起來有更好的效果。更多的研究是需要的。