Department of Newborn Research, Royal Women's Hospital, Melbourne, Australia.
Resuscitation. 2011 Jul;82(7):920-4. doi: 10.1016/j.resuscitation.2011.02.029. Epub 2011 Mar 27.
When using a T-piece device, resuscitators may try to improve airway pressures by increasing gas flow instead of correcting face mask position.
To measure the effects of changing gas flow during positive pressure ventilation (PPV) on peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP), expiratory tidal volume (V(Te)) and mask leak.
Using a Neopuff T-piece device, 20 neonatal staff members delivered PPV to a modified, leak-free manikin. Resuscitation parameters were recorded. Study A: PPV for 4 min at PIP 30 cm H(2)O and PEEP 5 cm H(2)O. Each minute gas flow was increased (5, 8, 10, and 15 L/min). PIP and PEEP settings were unchanged. Study B: same pressure settings; PPV for 1 min with 5, 8, 10, and 15 L/min in a random order, at a rate of ∼ 60/min. The pressures were adjusted to maintain the same PIP and PEEP after each flow change.
Study A: As gas flow increased (5, 8, 10 and 15 L/min) the median PEEP increased from 4.7 to 26.4 cm H(2)O (p<0.002). Median V(Te) decreased from 10.0 to 0.8 mL (p<0.001). PIP increased slightly from 30 cm H(2)O to 36 cm H(2)O at 15 L/min (p<0.005). Mask leak increased from 14% to 98% (p<0.001) because mask pressure increased. Study B: when PIP and PEEP were maintained there were no significant differences in V(Te) (p=0.42) or mask leak (p=0.51) with changing gas flow.
During PPV increasing gas flow dramatically increased PEEP and mask leak and in consequence reduced V(Te). Gas flow should rarely be changed during T-piece resuscitation.
使用 T 型件设备时，复苏者可能会尝试通过增加气流而不是纠正面罩位置来提高气道压力。
测量在正压通气 (PPV) 期间改变气流对吸气峰压 (PIP)、呼气末正压 (PEEP)、呼气潮气量 (V(Te)) 和面罩泄漏的影响。
使用新生儿复苏用 Neopuff T 型件设备，20 名新生儿医护人员对改良的、无泄漏的模型进行 PPV。记录复苏参数。研究 A：在 PIP 为 30cmH₂O 和 PEEP 为 5cmH₂O 的情况下，进行 4 分钟的 PPV。每分钟气流增加（5、8、10 和 15L/min）。PIP 和 PEEP 设置保持不变。研究 B：相同压力设置；以 5、8、10 和 15L/min 的顺序随机进行 1 分钟的 PPV，频率约为 60/min。在每次流量变化后，调整压力以保持相同的 PIP 和 PEEP。
研究 A：随着气流增加（5、8、10 和 15L/min），中位 PEEP 从 4.7cmH₂O 增加到 26.4cmH₂O（p<0.002）。中位 V(Te)从 10.0mL 减少到 0.8mL（p<0.001）。在 15L/min 时，PIP 略有增加，从 30cmH₂O 增加到 36cmH₂O（p<0.005）。由于面罩压力增加，面罩泄漏从 14%增加到 98%（p<0.001）。研究 B：当维持 PIP 和 PEEP 时，改变气流对 V(Te)（p=0.42）或面罩泄漏（p=0.51）没有显著差异。
在 PPV 期间，增加气流会显著增加 PEEP 和面罩泄漏，从而降低 V(Te)。在 T 型件复苏期间，应很少改变气流。
