Paulson T E, Spear R M, Silva P D, Peterson B M
Department of Pediatric Critical Care, San Diego Children's Hospital, California, USA.
J Pediatr. 1996 Oct;129(4):566-73. doi: 10.1016/s0022-3476(96)70122-1.
Animal models suggest that high-frequency ventilation with low tidal volumes and high positive end-expiratory pressure (PEEP) minimize secondary injury to the lung. We hypothesized that using a high-frequency pressure-control mode of ventilation with high PEEP in children with severe acute respiratory distress syndrome (ARDS) would be associated with improved survival.
The study was a retrospective and prospective clinical study at a 24-bed tertiary care pediatric critical care unit. Fifty-three patients with severe ARDS were studied during a 37-month period, 30 prospectively and 23 retrospectively. Severe ARDS was defined as (1) rapid onset of severe bilateral infiltrates of noncardiac origin, (2) partial pressure of oxygen (arterial)/fraction of inspired oxygen less than 200 on PEEP of 6 cm H2O or more for 24 hours or longer, and (3) Murray disease severity score greater than 2.5. All patients meeting these criteria underwent ventilation in the pressure-control mode; the protocol for ventilation had the following general guidelines: (1) fraction of inspired oxygen limited to 0.5, (2) mean airway pressure titrated with PEEP to maintain arterial partial pressure of oxygen of 55 mm Hg or greater (7.3 kPa), (3) peak inspiratory pressure minimized to allow hypercapnia (arterial partial pressure of carbon dioxide, 45 to 60 mm Hg (6.0 to 8.0 kPa), and (4) ventilator rates of 40 to 120/min. Percutaneous thoracostomy and mediastinal tubes were placed for treatment of air leak.
The survival rate was 89% (47/53) in children with severe ARDS. Nonsurvivors had significantly higher peak inspiratory pressures (75 vs 40 cm H2O, p = 0.0006), PEEP (23 vs 17 cm H2O, p = 0.0004), mean airway pressure (40 vs 28 cm H2O, p = 0.04), alveolar-arterial oxygen gradient (579 vs 540 mm Hg, p = 0.03), and oxygenation index (43 vs 19, p = 0.0008) than survivors. Air leak was present in 51% of patients; there was no difference in the incidence of air leak between survivors and nonsurvivors (p = 0.42).
The high-frequency positive-pressure mode of ventilation was safe and was associated with an improved survival rate (89%) for children with severe ARDS. Limitation of both inspired oxygen and tidal volume, along with aggressive treatment of air leak, may have contributed to the improved survival rate.
动物模型表明，采用低潮气量和高呼气末正压（PEEP）的高频通气可将肺部的继发性损伤降至最低。我们假设，在患有严重急性呼吸窘迫综合征（ARDS）的儿童中，采用高频压力控制通气模式并结合高PEEP会提高生存率。
本研究是在一家拥有24张床位的三级护理儿科重症监护病房进行的回顾性和前瞻性临床研究。在37个月的时间里，对53例重症ARDS患者进行了研究，其中30例为前瞻性研究，23例为回顾性研究。重症ARDS的定义为：（1）非心源性双侧严重浸润迅速出现；（2）在6 cm H2O或更高的PEEP水平下，动脉血氧分压/吸入氧分数小于200，持续24小时或更长时间；（3）默里疾病严重程度评分大于2.5。所有符合这些标准的患者均采用压力控制模式通气；通气方案有以下一般指导原则：（1）吸入氧分数限制在0.5；（2）通过PEEP滴定平均气道压力，以维持动脉血氧分压在55 mm Hg或更高（7.3 kPa）；（3）将吸气峰压降至最低以允许出现高碳酸血症（动脉血二氧化碳分压，45至60 mm Hg（6.0至8.0 kPa））；（4）通气频率为40至120次/分钟。放置经皮胸腔造口术和纵隔引流管以治疗气胸。
重症ARDS患儿的生存率为89%（47/53）。非存活者的吸气峰压（75 vs 40 cm H2O，p = 0.0006）、PEEP（23 vs 17 cm H2O，p = 0.0004）、平均气道压力（40 vs 28 cm H2O，p = 0.04）、肺泡-动脉氧梯度（579 vs 540 mm Hg，p = 0.03）和氧合指数（43 vs 19，p = 0.0008）均显著高于存活者。51%的患者出现气胸；存活者与非存活者的气胸发生率无差异（p = 0.42）。
高频正压通气模式是安全的，与重症ARDS患儿生存率的提高（89%）相关。对吸入氧和潮气量的限制，以及对气胸的积极治疗，可能有助于提高生存率。
