Greenough A, Milner A D, Dimitriou G
Dept of Child Health, King's College School of Medicine and Dentistry, Bessemer Road, London, UK, SE5 9PJ.
Cochrane Database Syst Rev. 2000(2):CD000456. doi: 10.1002/14651858.CD000456.
During synchronous ventilation, positive pressure ventilation and spontaneous inspiration coincide. Thus, if synchronous ventilation is provoked, it is likely that adequate gas exchange should be achieved at lower peak pressures, reducing barotrauma and hence airleak and chronic lung disease. Synchronous ventilation can be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient assisted ventilation.
To compare (i) the efficacy of synchronized mechanical ventilation, delivered as high frequency positive pressure ventilation or triggered ventilation (patient triggered ventilation (PTV) or synchronous intermittent mandatory ventilation (SIMV)) with conventional ventilation (ii) different types of triggered ventilation
Searches were made of the Oxford Database of Perinatal Trials, Medline (MESH terms: mechanical ventilation; triggered ventilation; newborn infant); previous reviews, abstracts, symposia proceedings, hand searching of journals in the English language and contacting expert informants.
Randomized or quasi randomized clinical trials comparing synchronized ventilation delivered as high frequency positive pressure ventilation (HFPPV) or triggered ventilation (PTV/SIMV) to conventional ventilation (CMV) in neonates. Randomized trials comparing different triggered ventilation modes (PTV and SIMV) in neonates.
Data regarding clinical outcomes including mortality, airleaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intracerebral haemorrhage (grades 3 and 4), chronic lung disease (oxygen dependency beyond 28 days) and duration of weaning/ventilation. Data subdivided into three groups: (i) HFPPV vs CMV; (ii) PTV/SIMV vs CMV; (iii) PTV vs SIMV. Data analysis was conducted according to the standards of the Neonatal Cochrane Review Group.
The meta-analysis demonstrates that HFPPV compared to CMV was associated with a reduction in the risk of airleak (typical relative risk 0.68, 95% CI 0.55, 0.68). PTV/SIMV compared to CMV was associated with a shorter duration of ventilation (Weighted mean difference -45.2 hours, 95% CI -78.3, -12.1). PTV compared to SIMV was associated with a trend to a shorter duration of weaning (Weighted mean difference 42.4 hours, 95% CI -9.6,94.4). No disadvantage to HFPPV or triggered ventilation was noted regarding other outcomes.
REVIEWER'S CONCLUSIONS: Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in airleak and a shorter duration of ventilation respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronized ventilation. Further trials are needed to determine whether synchronized ventilation is associated with a reduction in chronic oxygen dependency.
在同步通气过程中，正压通气与自主吸气同时发生。因此，如果引发同步通气，在较低的峰值压力下可能实现充分的气体交换，从而减少气压伤，进而减少气漏和慢性肺病的发生。通过在传统通气过程中调整速率和吸气时间以及采用患者辅助通气可以实现同步通气。
比较（i）以高频正压通气或触发通气（患者触发通气（PTV）或同步间歇指令通气（SIMV））方式进行的同步机械通气与传统通气的疗效，（ii）不同类型的触发通气
检索了牛津围产期试验数据库、Medline（医学主题词：机械通气；触发通气；新生儿）；既往综述、摘要、研讨会论文集，手工检索英文期刊并联系专家提供信息。
将高频正压通气（HFPPV）或触发通气（PTV/SIMV）与传统通气（CMV）进行比较的新生儿随机或半随机临床试验。比较新生儿不同触发通气模式（PTV和SIMV）的随机试验。
收集包括死亡率、气漏（气胸或肺间质肺气肿（PIE））、重度脑室内出血（3级和4级）、慢性肺病（28天以上的氧依赖）以及撤机/通气持续时间等临床结局的数据。数据分为三组：（i）HFPPV与CMV；（ii）PTV/SIMV与CMV；（iii）PTV与SIMV。根据新生儿Cochrane综述组的标准进行数据分析。
荟萃分析表明，与CMV相比，HFPPV与气漏风险降低相关（典型相对风险0.68，95%可信区间0.55，0.68）。与CMV相比，PTV/SIMV与通气持续时间缩短相关（加权平均差-45.2小时，95%可信区间-78.3，-12.1）。与SIMV相比，PTV与撤机持续时间缩短的趋势相关（加权平均差-42.4小时，95%可信区间-9.6，94.4）。在其他结局方面，未发现HFPPV或触发通气有不利之处。
与传统通气相比，HFPPV和触发通气分别在减少气漏和缩短通气持续时间方面显示出益处。在所有试验中均未进行复杂的呼吸监测，因此无法得出产生这些益处的机制是通过引发同步通气的结论。需要进一步的试验来确定同步通气是否与慢性氧依赖的降低相关。
