Fossat Guillaume, Alejos Roberto Martínez, Fresnel Emeline, Nay Mai-Anh, Medrinal Clément, Lebret Marius
Univ Rouen Normandie, GRHVN UR3830, Institute for Research and Innovation in Biomedicine (IRIB), 76000, Rouen, France.
Intensive Care Unit Department, ORLEANS University Hospital, 45067, Orléans, France.
Intensive Care Med Exp. 2025 Aug 5;13(1):78. doi: 10.1186/s40635-025-00788-y.
Spontaneous breathing trials (SBT) are crucial for determining when mechanically ventilated patients are ready for extubation. While pressure support (PS) and T-piece trials are commonly used, humidified high-flow (HHF) is increasingly considered, but its physiological effects remain unclear. This bench study compares T-piece, PS, and HHF modalities, evaluating their impact on work of breathing (WOB), tidal volume (Vt), total positive end-expiratory pressure (PEEPtot) and CO clearance.
A 3D-printed manikin head connected to an artificial lung was used. Four SBT modalities were tested: T-piece with and without supplemental oxygen, PS at 7 cmHO (PEEP 0 cmHO), and HHF at 50 L/min. The tests were performed under three lung conditions (normal, obstructive, restrictive) and two respiratory drive and effort settings (normal and intense), resulting in 24 scenarios. Measurements included WOB, CO clearance, PEEPtot, and Vt.
T-piece and HHF50 SBTs exhibited similar effects on WOB, irrespective of the effort pattern associated with the underlying respiratory mechanics. For intense effort patterns, the CO concentration was lower with HHF than with PS, regardless of respiratory mechanics. The HHF50 SBT increased PEEPtot more than T-piece SBTs, but less than PS SBT, for all scenarios. HHF50 SBT generated lower tidal volume than T-piece and PS SBTs.
Humidified high-flow at 50 L/min, while preserving WOB and not increasing tidal volume, may offer specific advantages, such as improved CO clearance and PEEP effect, and could be considered as a trade-off for T-piece or PS SBTs.
自主呼吸试验（SBT）对于确定机械通气患者何时准备好拔管至关重要。虽然压力支持（PS）和T管试验是常用的，但湿化高流量（HHF）越来越受到关注，但其生理效应仍不清楚。这项实验台研究比较了T管、PS和HHF模式，评估它们对呼吸功（WOB）、潮气量（Vt）、总呼气末正压（PEEPtot）和二氧化碳清除的影响。
使用连接到人工肺的3D打印人体模型头部。测试了四种SBT模式：带和不带补充氧气的T管、7cmH₂O的PS（PEEP 0cmH₂O）和50L/min的HHF。测试在三种肺部条件（正常、阻塞性、限制性）和两种呼吸驱动及用力设置（正常和强烈）下进行，共产生24种情况。测量包括WOB、二氧化碳清除、PEEPtot和Vt。
无论与潜在呼吸力学相关的用力模式如何，T管和HHF50 SBT对WOB表现出相似的影响。对于强烈的用力模式，无论呼吸力学如何，HHF的二氧化碳浓度均低于PS。在所有情况下，HHF50 SBT使PEEPtot增加的幅度大于T管SBT，但小于PS SBT。HHF50 SBT产生的潮气量低于T管和PS SBT。
50L/min的湿化高流量在保持WOB且不增加潮气量的同时，可能具有特定优势，如改善二氧化碳清除和PEEP效应，可被视为T管或PS SBT的一种替代方案。
