8月29日《New England Journal of Medicine》发表的一篇社论提到,早产儿所使用的高频振动空气流通器(HFOV)应该在几个特定的医疗中心保留下来,其它的中心应该继续使用传统的低潮气量通气器。在同一期杂志中公布的一项研究发现,高频技术可以带来小但明显的利益;但另一项研究则发现,高频技术对早产儿无益也无害。
  新泽西州Camden的大学医疗中心的Sherry E. Courtney医师及其同事认为,分配到HFOV组的早产儿能更早地成功拔管,且生存下来无慢性肺病的婴儿数量增加。这说明在经验丰富的医疗中心,HFOV能产生小但明显的利益。在这些医疗中心,[HFOV]应被考虑作为早产儿呼吸支持的第一线方法。
  在多中心试验中,Dr. Courtney研究小组将500名出生体重在601至1,200 g的婴儿随机分配到HFOV组或同步间断强制通气组。所有婴儿都处于出生后4小时之内,接受一剂表面活性剂,需要平均气道阻力至少为6cm水柱、吸入氧分数至少为0.25的通气量。
  HFOV治疗组婴儿比常规通气组提前一周成功拔管(P<0.001)。在36周时,HFOV组有56%的婴儿存活,且不需要补充氧气,而传统通气组则为47% (P=0.046)。颅内出血、囊性脑室周围软化及其它并发症两组结果类似。
  英国振动研究组的Dr. Alice H. Johnson及其同事认为,对出生体重极低的婴儿而言,与使用呼吸支持的传统通气疗法相比,HFOV的安全性和有效性仍不确定。在随机试验中,400名早产儿接受HFOV治疗,397名接受传统的通气治疗。在36周时出现死亡或诊断为慢性肺病等主要结果的婴儿比例,HFOV组为66%,而传统通气疗法组为68%。次要后果在两组之间也没有差异。
  在麻萨诸塞州波士顿的Brigham及妇女医院的Ann H. Stark医师所写的社论提到,该研究结果更接近于早前的试验结果。该研究与Dr. Courtney研究团队的可能差异包括:后者研究的婴儿更虚弱、呼吸机类型及通气治疗操作的差异,医生治疗经验的差异。
  Dr. Stark指出,经验不足的医生操作HFOV有潜在的危险。在Dr. Johnson等进行的研究中,通气治疗可能更能代表很多新生儿重症护理病房的实际水平。根据严格的协定管理HFOV,可能在经验最丰富的医疗中心更可取。但是,对大多数早产儿而言,低潮气量的传统机械通气以及合理的通气目标仍然是合理的选择。

High-Frequency Oscillatory Ven

By Laurie Barclay, MD
Medscape Medical News

Aug. 29, 2002 — High-frequency oscillatory ventilation (HFOV) for premature infants should be reserved to a few select centers, while the others should continue conventional low tidal volume ventilation, according to an editorial in the Aug. 29 issue of the New England Journal of Medicine. One study in the same issue shows a small but significant benefit from the high-frequency technique, but another study shows neither benefit nor harm.

"The marked decrease in the number of days before successful extubation and the increase in the number of infants who survived without chronic lung disease in the group assigned to HFOV suggest that HFOV offers a small but significant benefit at experienced centers," write Sherry E. Courtney, MD, from University Medical Center in Camden, New Jersey, and colleagues. "In such settings, [HFOV] should be considered the first line of ventilatory ssupport in this group of very preterm infants."

In this multicenter trial, Courtney's group randomized 500 infants weighing 601 to 1,200 g at birth to HFOV or synchronized intermittent mandatory ventilation. All infants were less than four hours of age, had received one dose of surfactant, and required ventilation with a mean airway pressure of at least 6 cm of water and a fraction of inspired oxygen of at least 0.25.

Infants treated with HFOV were successfully extubated about one week earlier than those treated with conventional ventilation (P<.001). At 36 weeks of postmenstrual age, 56% of infants in the HFOV group were alive and did not require supplemental oxygen compared with 47% in the conventionally ventilated group (P=.046). Rates of intracranial hemorrhage, cystic periventricular leukomalacia, and other complications were similar in both groups.

"There remains uncertainty concerning the safety and efficacy of HFOV as compared with those of conventional ventilation for the respiratory support of very preterm infants," write Alice H. Johnson, MB, ChB, and colleagues from the United Kingdom Oscillation Study Group. In their randomized study, 400 preterm infants received HFOV and 397 received conventional ventilation. The composite primary outcome of death or chronic lung disease diagnosed at 36 weeks of postmenstrual age occurred in 66% of the infants receiving HFOV and in 68% of those on conventional ventilation. Secondary outcomes also did not differ between groups.

According to an editorial by Ann H. Stark, MD, from Brigham and Women's Hospital in Boston, Massachusetts, the results of this study most closely approximate those of earlier trials. Possible differences between this study and that of Courtney's group may include sicker infants in the latter study, differences in types of ventilators or in the management of ventilation, or varying experience of the clinicians.

"The management of ventilation in the study by Johnson et al. may better represent actual practice in many newborn intensive care units," she writes, noting potential risks of HFOV in inexperienced hands. "HFOV administered according to strict protocols may be preferable in the most experienced centers. However, for most preterm infants, conventional mechanical ventilation with low tidal volumes and reasonable ventilation goals remains the appropriate choice."

N Engl J Med. 2002;347(9):633-642, 643-652, 682-684

Reviewed by Gary D. Vogin, MD

2011/7/8 下午 05:15:16
2010/2/12 上午 10:30:00
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