Chest
Laboratory and Animal InvestigationsEffects of Spontaneous Breathing During Airway Pressure Release Ventilation on Respiratory Work and Muscle Blood Flow in Experimental Lung Injury
Section snippets
Instrumentation
The principles of laboratory animal care (revised National Institutes of Health guidelines, 1985) were followed, and the study was approved by the local Laboratory Animal Care and Use Committee. Twelve pigs, mixed German country breed, weighing 10 to 19 kg (15.2 ± 0.8 kg [mean ± SEM]) were fasted for 24 h while having free access to water. Prior to instrumentation, animals were premedicated with IM ketamine (10 mg/kg), xylazine hydrochloride (2 mg/kg), and glyopyrronium bromide (15 μg/kg) and
Results
For validation of the microspheres technique, adequate mixing of injected microspheres and even distribution of blood flow to the various organs were indicated by highly significant correlations between the number of microspheres trapped in the two reference blood samples (5,030 ± 619 microspheres per sample vs 4,848 ± 556 microspheres per sample, r = 0.95) and the blood flows to the right and left adrenal glands (1.99 ± 0.22 mL/g/min vs 1.91 ± 0.25 mL/g/min, r = 0.94) [p < 0.0001,
Discussion
The aim of our study was to investigate the effects of spontaneous breathing on respiratory work and RMBF in a pig model with oleic acid-induced lung injury. We found that PTPinsp and diaphragmatic blood flow markedly increased when animals with lung injury were breathing spontaneously at ambient Paw, and that ventilatory support with APRV resulted in a reduction of PTPinsp and diaphragmatic blood flow to normal physiologic values not different from those obtained in animals with normal lungs
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Cited by (31)
Does airway pressure release ventilation offer new hope for treating acute respiratory distress syndrome?
2022, Journal of Intensive MedicineCitation Excerpt :There are three common methods for ARDS model establishment: (1) oleic acid injection, (2) saline lung lavage, and (3) ischemia-reperfusion and peritoneal sepsis. Most studies indicated that SB during APRV can improve oxygenation, decreases respiratory work, and redistribute ventilation to the dependent lung area, thereby reducing VILI.[52–58] Most studies compared CV modes and APRV in the animal ALI model and found that APRV had lower lung injury histological scores and could reduce cytokine mRNA expressions in lung tissue and reduce tumor necrosis factor (TNF)-a, interleukin (IL)−8, and IL-6 in the bronchoalveolar lavage fluid (BALF).[56,58–60]
Airway pressure release ventilation
2020, BJA EducationCitation Excerpt :There have been multiple experiments predominantly using porcine or rodent animal models to investigate whether APRV confers any advantage or harm compared with conventional ventilation. In animal models, APRV improves arterial oxygenation, increases ventilation in dependent areas of lung, reduces inflammatory cytokine production, and can prevent the development of ARDS.11–15 One of the most striking animal experiments was in pigs with induced sepsis, randomised to receive APRV or ‘ARDSnet protocol’ low tidal volume (LTV) ventilation.15
Spontaneous breathing improves shunt fraction and oxygenation in comparison with controlled ventilation at a similar amount of lung collapse
2011, Anesthesia and AnalgesiaCitation Excerpt :The present study to our knowledge is the first to compare nonassisted SB with MV set to the same small tidal volumes and low pressures as during SB. The explanation for the improvement in gas exchange with SB efforts has been reduction in atelectatic lung areas close to the diaphragm, supporting the concept of reopening of dependent lung regions by diaphragmatic contractions.1–5,17–22 This is a possible mechanism in APRV or BiPAP in which tidal volumes are not necessarily as small as the “biological” Vt of SB adopted in this study.
Assessment of spontaneous breathing during pressure controlled ventilation with superimposed spontaneous breathing using respiratory flow signal analysis
2021, Journal of Clinical Monitoring and Computing
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