Richard Jean-Christophe, Brochard Laurent, Breton Lucie, Aboab Jérôme, Vandelet Philippe, Tamion Fabienne, Maggiore Salvatore M, Mercat Alain, Bonmarchand Guy
Medical Intensive Care Unit, University Hospital-Charles Nicolle, 1 rue de Germont, 76031 Rouen, France.
Intensive Care Med. 2002 Aug;28(8):1078-83. doi: 10.1007/s00134-002-1349-8. Epub 2002 Jun 15.
Reduction in tidal volume (Vt) associated with increase in respiratory rate to limit hypercapnia is now proposed in patients with acute lung injury (ALI). The aim of this study was to test whether a high respiratory rate induces significant intrinsic positive end-expiratory pressure (PEEPi) in these patients.
Prospective crossover study.
A medical intensive care unit.
Ten consecutive patients fulfilling criteria for severe ALI were ventilated with a 6 ml/kg Vt, a total PEEP level at 13+/-3 cmH(2)O and a plateau pressure kept at 23+/-4 cmH(2)O. The respiratory rate was randomly set below 20 breaths/min (17+/-3 breaths/min) and increased to 30 breaths/min (30+/-3 breaths/min) to compensate for hypercapnia. External PEEP was adjusted to keep the total PEEP and the plateau pressure constant. PEEPi was computed as the difference between total PEEP and external PEEP. The lung volume retained by PEEPi was then measured.
Increase in respiratory rate resulted in significantly higher PEEPi (1.3+/-0.4 versus 3.9+/-1.1 cmH(2)O, p<0.01) and trapped volume (70+/-43 versus 244+/-127 ml, p<0.01). External PEEP needed to be reduced from 11.9+/-3.4 to 9.7+/-2.9 cmH(2)O ( p<0.01). PaO(2) was not affected but the alveolar-arterial oxygen tension difference slightly worsened with the high respiratory rate (p<0.05).
An increase in respiratory rate used to avoid Vt reduction-induced hypercapnia may induce substantial gas trapping and PEEPi in patients with ALI.
目前建议对急性肺损伤（ALI）患者降低潮气量（Vt）并增加呼吸频率以限制高碳酸血症。本研究的目的是测试高呼吸频率是否会在这些患者中诱发显著的内源性呼气末正压（PEEPi）。
前瞻性交叉研究。
医疗重症监护病房。
连续10例符合重症ALI标准的患者接受通气治疗，Vt为6 ml/kg，总PEEP水平为13±3 cmH₂O，平台压维持在23±4 cmH₂O。呼吸频率随机设定低于20次/分钟（17±3次/分钟），并增加至30次/分钟（30±3次/分钟）以补偿高碳酸血症。调整外部PEEP以保持总PEEP和平台压恒定。PEEPi计算为总PEEP与外部PEEP之差。然后测量由PEEPi保留的肺容积。
呼吸频率增加导致PEEPi显著升高（1.3±0.4对3.9±1.1 cmH₂O，p<0.01）和潴留容积增加（70±43对244±127 ml，p<0.01）。外部PEEP需要从11.9±3.4 cmH₂O降至9.7±2.9 cmH₂O（p<0.01）。PaO₂未受影响，但高呼吸频率时肺泡-动脉氧分压差略有恶化（p<0.05）。
为避免Vt降低引起的高碳酸血症而增加呼吸频率，可能会在ALI患者中导致大量气体潴留和PEEPi。
Zotero 插件