Effects of increasing PEEP on lung stress and strain in children with and without ARDS

Abstract

The ratio of tidal volume to functional residual capacity (FRC), defined as "volumetric" strain, causes physical lung deformation. The corresponding change in transpulmonary pressure at end inspiration, defined as stress, is directly applied to the alveolus [1]. Both stress and strain may cause global or local lung deformation and microscopic or macroscopic tissue damage, representing significant determinants of ventilator-induced lung injury [1]. A modified nitrogen washout/washin technique, measuring end-expiratory lung volume (EELV), correlated well with computed tomography and was proposed as a valuable tool to optimize ventilator settings, improving lung protective ventilation [2]. The aim of this study was to evaluate the effect of positive end-expiratory pressure (PEEP) on EELV, compliance of the respiratory system (Crs), and stress/strain in children with acute respiratory distress syndrome (ARDS), and compare it with children "at risk of ARDS" and those with no lung injury using the modified nitrogen washout/washin technique (see electronic supplementary material). To monitor the effects of the disease evolution on the PEEP-induced increases in lung stress/strain, measurements were repeated at predetermined time points. We hypothesized that PEEP escalation increases EELV, Crs, strain, and stress in mechanically ventilated children, potentially influenced by disease severity and timing. A total of 700 measurements were recorded in 25 mechanically ventilated critically ill children (ARDS, n = 8; at risk of ARDS, n = 5; without lung injury, n = 12). ARDS patients had higher oxygenation index (OI > 4) and PaCO 2 , lower PaO 2 /FiO 2 , PaO 2 , and prolonged length of

Different positive end expiratory pressure and tidal volume controls on lung protection and inflammatory factors during surgical anesthesia

“…Small tidal volume combined with PEEP has been widely used in the clinical treatment of acute lung injury and has achieved good clinical results. However, with the increase in PEEP, the venous return flow may be decreased, and the arterial vascular resistance will be increased, which may affect cardiac output and increase the risk of lung injury, especially for elderly patients under general anesthesia[ 15 - 17 ].…”

Longitudinal PEEP Responses Differ Between Children With ARDS and at Risk for ARDS

“…32 The steadily increased strain and stress related to ARDS in this study assumes that this phenomenon is more exacerbated in subjects with ARDS compared to subjects at risk for ARDS, expanding results of previous studies that reported higher strain and stress in adults and in children with lung injury compared to healthy individuals. 14,27 The "lung injury" limits for strain may be exceeded by increasing the V T in patients with low C RS . Depending on recruitment potential, static hyperaeration produced by unnecessarily high PEEP might add tidal (dynamic) volume to the static hyperinflation.…”

The best PEEP or the optimal PEEP or the piece PEEP of the mechanical power puzzle?

“…1186/ s13054-022-04084-z. *Correspondence: ggbriass@otenet.gr; briasoug@uoc.gr 1 Postgraduate Program "Emergency and Intensive Care in Children Adolescents and Young Adults", Pediatric Intensive Care Unit, School of Medicine, University of Crete, Section 6D (Delta), Office 03, Voutes, 71003 Heraklion, Crete, Greece Full list of author information is available at the end of the article but not compliance (Crs), increased from PEEP 4 to PEEP 10 cmH 2 O (p = 0.001) in ARDS pediatric patients longitudinally [3]. Previous experimental and clinical studies have similarly questioned the reliability of Crs for lung recruitment/derecruitment estimation in ARDS.…”

“…Personalizing PEEP to target optimal compliance might identify ARDS patients with functional lung units, avoiding the indiscrete application of high PEEP [ 2 ]. Using the nitrogen washout/washin technique, we have recently demonstrated that end-expiratory lung volume (EELV), but not compliance (Crs), increased from PEEP 4 to PEEP 10 cmH 2 O ( p = 0.001) in ARDS pediatric patients longitudinally [ 3 ]. Previous experimental and clinical studies have similarly questioned the reliability of Crs for lung recruitment/derecruitment estimation in ARDS.…”