Goldman S L, McCann E M, Lloyd B W, Yup G
Department of Pediatrics, California Pacific Medical Center, San Francisco 94118.
Pediatr Pulmonol. 1991;11(3):198-201. doi: 10.1002/ppul.1950110303.
To learn if increasing inspiratory time would improve pulmonary function in mechanically ventilated babies with chronic lung disease, we measured lung mechanics and alveolar ventilation at three inspiratory times: 0.4, 0.6, and 0.8 s. Nine babies were studied. Their mean birth weight was 875 g (range, 570-1,100 g), gestational age 27 (24-34) weeks, and age 7 (4-12) weeks. Their mean oxygen requirement was 40% (29-53), ventilator rate 33/min (20-40), and mean airway pressure 8 (5-10) cmH2O. Ventilator rate was kept constant; therefore expiratory time decreased and mean airway pressure and I:E ratio increased at longer inspiratory times. At 0.6 s and 0.8 s, when compared to 0.4 s, significant increases occurred in tidal volume (10.4, 10.1, and 8.4 mL/kg, respectively), dynamic lung compliance (0.68, 0.68, and 0.53 mL/cmH2O/kg, respectively), and alveolar ventilation (6.0, 6.3, and 4.7 mL/kg/breath, respectively). Airway resistance, anatomical dead space to tidal volume ratio, and functional residual capacity were similar at the three inspiratory times. Our findings suggest that an inspiratory time greater than or equal to 0.6 s (compared to 0.4 s) increases the effectiveness of mechanical ventilation for babies with chronic lung disease.
为了了解延长吸气时间是否会改善患有慢性肺病的机械通气婴儿的肺功能，我们在三个吸气时间点（0.4秒、0.6秒和0.8秒）测量了肺力学和肺泡通气。对9名婴儿进行了研究。他们的平均出生体重为875克（范围为570 - 1100克），胎龄27（24 - 34）周，年龄7（4 - 12）周。他们的平均氧气需求量为40%（29 - 53），呼吸机频率为33次/分钟（20 - 40），平均气道压力为8（5 - 10）厘米水柱。呼吸机频率保持恒定；因此，在较长吸气时间时呼气时间缩短，平均气道压力和吸气与呼气时间比增加。在0.6秒和0.8秒时，与0.4秒相比，潮气量（分别为10.4、10.1和8.4毫升/千克）、动态肺顺应性（分别为0.68、0.68和0.53毫升/厘米水柱/千克）和肺泡通气（分别为6.0、6.3和4.7毫升/千克/呼吸）显著增加。在三个吸气时间点，气道阻力、解剖死腔与潮气量比以及功能残气量相似。我们的研究结果表明，吸气时间大于或等于0.6秒（与0.4秒相比）可提高对患有慢性肺病婴儿机械通气的有效性。
