ECMO criteria for influenza A (H1N1)-associated ARDS: role of transpulmonary pressure

Abstract

This is an author version of the contribution published on:Questa è la versione dell'autore dell'opera: [Intensive Care Medicine,38(3),2012, doi: 10.1007/s00134-012-2490 The definitive version is available at: La versione definitiva è disponibile alla URL: [http://download.springer.com/static/pdf/687/art%253A10.1007%252Fs00 134-012-2490 Conclusions:Abnormalities of chest wall mechanics may be present in some patients with influenza A (H1N1)-associated ARDS. These abnormalities may not be inferred from measurements of end-inspiratory plateau pressure of the respiratory system 1 (PPLAT RS ). In these patients, titrating PEEP on PPLAT RS may overestimate the incidence of hypoxemia refractory to conventional ventilation leading to un-appropriate use of ECMO.

Two Steps Forward in Bedside Monitoring of Lung Mechanics: Transpulmonary Pressure and Lung Volume

“…Other studies suggest Pes measurement as a physi ologically defensible and reliable tool for estimating P TP in critically ill patients [13,14,16]. As an ex ample of such enthusiastic reports, Grasso et al [16] evaluated whether keeping end-inspi ratory P TP within a theoretically innocuous range might allow safe increases of PEEP in pursuit of improved oxygenation.…”

“…As an ex ample of such enthusiastic reports, Grasso et al [16] evaluated whether keeping end-inspi ratory P TP within a theoretically innocuous range might allow safe increases of PEEP in pursuit of improved oxygenation. Th ese authors found that relaxing the excessively prudent P AW -based criteria for safe ventilation (justifi ed by P TP cal culations) may avoid unnecessary use of extracorporeal membrane oxygenation (ECMO) in patients with ALI/ARDS from infl uenza A (H1N1) infection [16].…”

Transpulmonary pressure as a surrogate of plateau pressure for lung protective strategy: not perfect but more physiologic

“…However, in patient with ARDS related to intra-abdominal disease and in those exhibiting high BMI, the chest wall may account for a much higher proportion of total elastance [14,15]. In accordance with those observations, Grasso et al [5] suggested that targeting Pplat of 30 cmH 2 O may be excessively prudent in some patients and may lead to unjustified recommendations for ECMO management. On the other hand, Terragni et al [16] showed in 30 patients managed according to the ARDS network strategy that one-third experienced tidal hyperinflation [assessed by CT scan systematic analysis] despite a Vt of 6 ml/kg PBW and a Pplat limited at 30 cmH 2 O.…”

“…In this issue of Intensive Care Medicine, Grasso et al [5] evaluate whether the use of transpulmonary pressure (PTP) [as opposed to airway pressure (Paw) alone] as a surrogate of the true lung distending pressure might lead to safely increased positive end-expiratory pressure (PEEP) and improved oxygenation, thereby avoiding unnecessary ECMO. In fact, whereas Paw is influenced by chest wall properties and respiratory muscle activity, the PTP (Paw -pleural pressure) enables estimation of passive lung's actual distending pressure, unencumbered by the influence of the chest wall and patient effort on recorded airway pressures.…”

Rescue therapy for refractory ARDS should be offered early: no

“…Is there room for Pplat greater than 30 cmH 2 O due to impairment of elastic properties of the chest wall? Grasso et al [7] were able to avoid ECMO in seven severe influenza A(H1N1)-associated ARDS patients with high chest wall elastance that allowed the PEEP to be raised in order to reach a transpulmonary pressure of 25 cmH 2 O. Such measurements require the insertion of an esophageal balloon.…”