Service de Réanimation Médicale, AP-HP, Centre Hospitalier Albert Chenevier-Henri Mondor, Créteil, France.
Crit Care Med. 2013 Sep;41(9):2125-32. doi: 10.1097/CCM.0b013e31828a42e5.
During proportional assist ventilation with load-adjustable gain factors, peak respiratory muscle pressure can be estimated from the peak airway pressure and the percentage of assistance (gain). Adjusting the gain can, therefore, target a given level of respiratory effort. This study assessed the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors with the goal of targeting a predefined range of respiratory effort.
Prospective, multicenter, clinical observational study.
Intensive care departments at five university hospitals.
Patients were included after meeting simple criteria for assisted mechanical ventilation.
Patients were ventilated in proportional assist ventilation with load-adjustable gain factors. The peak respiratory muscle pressure, estimated in cm H2O as (peak airway pressure-positive end-expiratory pressure)×[(100-gain)/gain], was calculated from a grid at the bedside. The gain adjustment algorithm was defined to target a peak respiratory muscle pressure between 5 and 10 cm H2O. Additional recommendations were available in case of hypoventilation or hyperventilation.
Fifty-three patients were enrolled. Median time spent under proportional assist ventilation with load-adjustable gain factors was 3 days (interquartile range, 1-5). Gain was adjusted 1.0 (0.7-1.8) times per day, according to the peak respiratory muscle pressure target range in 91% of cases and because of hypoventilation or hyperventilation in 9%. Thirty-four patients were ventilated with proportional assist ventilation with load-adjustable gain factors until extubation, which was successful in 32. Eighteen patients required volume assist-controlled reventilation because of clinical worsening and need for continuous sedation. One patient was intolerant to proportional assist ventilation with load-adjustable gain factors.
This first study assessing the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors in an attempt to target a predefined range of effort showed that adjusting the level of assistance to maintain a predefined boundary of respiratory muscle pressure is feasible, simple, and often sufficient to ventilate patients until extubation.
在带可调增益因子的比例辅助通气中，可以根据气道峰压和辅助百分比（增益）估计最大呼吸肌压力。因此，调整增益可以使呼吸努力达到特定水平。本研究评估了使用带可调增益因子的比例辅助通气进行滴定以达到预设呼吸努力范围的临床可行性。
前瞻性、多中心、临床观察研究。
五所大学医院的重症监护病房。
符合辅助机械通气简单标准的患者入选。
患者接受带可调增益因子的比例辅助通气。最大呼吸肌压力（cmH2O）通过床边的网格计算，公式为（气道峰压+呼气末正压）×[（100-增益）/增益]。增益调整算法定义为使最大呼吸肌压力在 5 至 10cmH2O 之间。如果出现通气不足或通气过度，还提供了其他建议。
共纳入 53 例患者。患者接受带可调增益因子的比例辅助通气中位时间为 3 天（四分位间距，1-5 天）。根据 91%病例的最大呼吸肌压力目标范围，以及 9%病例的通气不足或通气过度，每天调整增益 1.0（0.7-1.8）次。34 例患者在带可调增益因子的比例辅助通气下进行通气，直至成功拔管。18 例患者因临床恶化和需要持续镇静而需要接受容量辅助控制再通气。1 例患者不能耐受带可调增益因子的比例辅助通气。
这是第一项评估尝试通过调整带可调增益因子的比例辅助通气以达到预设努力范围的临床可行性的研究，结果表明，调整辅助水平以维持预设的呼吸肌压力边界是可行的、简单的，并且通常足以使患者通气直至拔管。
