Department of Anaesthesiology, Intensive Care and Pain, Hospital Universitario Puerta de Hierro-Majadahonda, Majadahonda, Spain.
Medical and Surgical Research Unit, Instituto de Investigación Sanitaria Puerta de Hierro-Segovia de Arana. Hospital Universitario Puerta de Hierro-Majadahonda, Majadahonda, Spain.
Respir Care. 2022 Oct;67(10):1300-1309. doi: 10.4187/respcare.09739. Epub 2022 Jul 19.
The aim of this study was to define the level of peak inspiratory pressure (PIP) and mean airway pressure ([Formula: see text]) at which a pneumothorax is produced in an in vivo ARDS neonate model. In addition, we analyzed the hemodynamic response and cerebral parameters during the progressive increase of intrathoracic pressure.
We designed a prospective, experimental study with 11 Landrace × Large White pigs < 48 h from their birth. With the pigs under general anesthesia, tracheal intubation, invasive hemodynamic monitoring with a pediatric arterial thermodilution catheter, intracranial pressure, cerebral oximetry through near-infrared spectroscopy, and bilateral chest tube catheterization were performed. The ARDS model was developed with bronchoalveolar lavages. The rise in inspiratory pressure was performed achieved by increasing PEEP in stepwise increments at a constant driving pressure. PEEP was increased 5 cm HO every 2 min until a pneumothorax was observed. A descriptive analysis, a Kaplan-Meier curve, and a regression analysis by using a generalized estimation equation were performed.
A pneumothorax was observed in a median (interquartile range [IQR]) [Formula: see text] of 54 (46-56) cm HO and median (IQR) PIP of 65 (58-73) cm HO; asystole at median (IQR) [Formula: see text] of 49 (36-54) cm HO and median (IQR) PIP of 60 (48-65) cm HO. Hemodynamic changes in the median artery pressure, cardiac output, and myocardial contractility were observed above the range of [Formula: see text] of 14 cm HO (PIP 25 and PEEP 10 cm HO). Disturbances in intracranial pressure and cerebral oximetry through near-infrared spectroscopy appeared when deep hypotension and asystole occurred.
A progressive increase of PEEP at a constant driving pressure did not increase severe adverse events at the range of pressures that we routinely use in neonates with ARDS. Asystole, pneumothorax, and cerebral compromise appeared at high intrathoracic ranges of pressure. Hemodynamics must be strictly monitored in all patients during the performance of lung recruitment maneuvers because hemodynamic deflections emerge early, at a range of pressures commonly used in ventilated neonates with ARDS.
本研究旨在确定在活体 ARDS 新生儿模型中产生气胸时的峰吸气压（PIP）和平均气道压（[Formula: see text]）水平。此外，我们还分析了在逐渐增加胸腔内压力过程中的血流动力学反应和脑参数。
我们设计了一项前瞻性、实验性研究，纳入了 11 头出生不到 48 小时的长白 × 大约克猪。在猪全身麻醉、气管插管、使用小儿动脉热稀释导管进行有创血流动力学监测、颅内压、近红外光谱脑氧饱和度以及双侧胸腔管置管后，我们建立了 ARDS 模型。通过支气管肺泡灌洗建立 ARDS 模型。通过在恒定驱动压力下逐步增加 PEEP 来实现吸气压力的升高。每 2 分钟增加 5 cm H2O 的 PEEP，直到观察到气胸为止。我们进行了描述性分析、Kaplan-Meier 曲线和使用广义估计方程的回归分析。
中位数（四分位距 [IQR]）为 54（46-56）cm H2O 的[Formula: see text]和中位数（IQR）为 65（58-73）cm H2O 的 PIP 观察到气胸；中位数（IQR）为 49（36-54）cm H2O 的[Formula: see text]和中位数（IQR）为 60（48-65）cm H2O 的 PIP 发生心脏停搏。在[Formula: see text]为 14 cm H2O（PIP 25 和 PEEP 10 cm H2O）以上的范围中观察到了中动脉压、心输出量和心肌收缩力的血流动力学变化。当出现深度低血压和心脏停搏时，通过近红外光谱的颅内压和脑氧饱和度出现干扰。
在我们常规用于 ARDS 新生儿的压力范围内，在恒定驱动压力下逐渐增加 PEEP 不会增加严重不良事件。在较高的胸腔内压力范围内出现心脏停搏、气胸和脑损伤。在进行肺复张手法时，所有患者都必须严格监测血流动力学，因为在 ARDS 新生儿常规使用的压力范围内，血流动力学偏差会较早出现。
