Journal article
Effects of Lung Injury and Abdominal Insufflation on Respiratory Mechanics and Lung Volume During Time-Controlled Adaptive Ventilation
Respiratory care, Vol.69(11), pp.1432-1443
11/01/2024
DOI: 10.4187/respcare.11745
PMCID: PMC11549635
PMID: 38408775
Abstract
Lung volume measurements are important for monitoring functional aeration and recruitment, and may help guide adjustments in ventilator settings. The expiratory phase of APRV may provide physiologic information about lung volume based on the expiratory flow-time slope, angle, and time to approach a no-flow state (T
). We hypothesized that expiratory flow rate would correlate with estimated lung volume (ELV), as measured using a modified nitrogen washout/washin technique in a large animal lung injury model.
Eight pigs (35.2±1.0kg) were mechanically ventilated using an Engström Carescape R860 on the APRV mode. All settings were held constant except the expiratory duration (T
), which was adjusted based on the expiratory flow curve. Abdominal pressure was increased to 15mmHg in normal and Tween-injured lungs to replicate a combination of pulmonary and extrapulmonary lung injury. ELV was estimated using the Carescape FRC InView Tool. The expiratory flow-time slope and T
were measured from the expiratory flow profile.
Lung elastance increased with Tween-induced lung injury from 29.3±7.3cmH
O/L to 39.9±15.1cmH
O/L and chest wall elastance increased with increasing intra-abdominal pressures from 15.3±4.1cmH
O/L to 25.7±10.0cmH
O/L in the normal lung and 15.8±6.0cmH
O/L to 33.0±6.2cmH
O/L in the Tween-injured lung (p=0.39). ELV decreased from 1.90±0.83L in the Tween-Injured lung to 0.67±0.1L by increasing intra-abdominal pressures to 15mmHg. This had a significant correlation with a T
decrease from 2.3±0.8s to 1.0±0.1s in the Tween-injured group with increasing insufflation pressures (ρ = 0.95) and with the expiratory flow-time slope, which increased from 0.29±0.06L/s
to 0.63±0.05L/s
(ρ = 0.78).
Changes in ELV over time, and the T
and flow-time slope, can be used to demonstrate evolving lung injury during APRV. Using the slope to infer changes in functional lung volume represents a unique, reproducible, real-time, bedside technique that does not interrupt ventilation and may be used for clinical interpretation.
Details
- Title: Subtitle
- Effects of Lung Injury and Abdominal Insufflation on Respiratory Mechanics and Lung Volume During Time-Controlled Adaptive Ventilation
- Creators
- Harry Ramcharran - SUNY Upstate Medical UniversityGreg Wetmore - University of CincinnatiScott Cooper - Morehouse School of MedicineJacob Herrmann - University of IowaAndrea F Cruz - Department of Anesthesia, University of Iowa, Iowa City, IADavid W Kaczka - University of IowaJoshua Satalin - SUNY Upstate Medical UniversitySarah Blair - SUNY Upstate Medical UniversityPenny L Andrews - University of Maryland Medical CenterNader M Habashi - University of Maryland Medical CenterGary F Nieman - SUNY Upstate Medical UniversityMichaela Kollisch-Singule - SUNY Upstate Medical University
- Resource Type
- Journal article
- Publication Details
- Respiratory care, Vol.69(11), pp.1432-1443
- DOI
- 10.4187/respcare.11745
- PMID
- 38408775
- PMCID
- PMC11549635
- NLM abbreviation
- Respir Care
- eISSN
- 1943-3654
- Language
- English
- Electronic publication date
- 02/26/2024
- Date published
- 11/01/2024
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Anesthesia
- Record Identifier
- 9984563557702771
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