Respiratory pulse pressure variation fails to predict fluid responsiveness in acute respiratory distress syndrome

Abstract

IntroductionFluid responsiveness prediction is of utmost interest during acute respiratory distress syndrome (ARDS), but the performance of respiratory pulse pressure variation (ΔRESPPP) has scarcely been reported. In patients with ARDS, the pathophysiology of ΔRESPPP may differ from that of healthy lungs because of low tidal volume (Vt), high respiratory rate, decreased lung and sometimes chest wall compliance, which increase alveolar and/or pleural pressure. We aimed to assess ΔRESPPP in a large ARDS population.MethodsOur study population of nonarrhythmic ARDS patients without inspiratory effort were considered responders if their cardiac output increased by >10% after 500-ml volume expansion.ResultsAmong the 65 included patients (26 responders), the area under the receiver-operating curve (AUC) for ΔRESPPP was 0.75 (95% confidence interval (CI95): 0.62 to 0.85), and a best cutoff of 5% yielded positive and negative likelihood ratios of 4.8 (CI95: 3.6 to 6.2) and 0.32 (CI95: 0.1 to 0.8), respectively. Adjusting ΔRESPPP for Vt, airway driving pressure or respiratory variations in pulmonary artery occlusion pressure (ΔPAOP), a surrogate for pleural pressure variations, in 33 Swan-Ganz catheter carriers did not markedly improve its predictive performance. In patients with ΔPAOP above its median value (4 mmHg), AUC for ΔRESPPP was 1 (CI95: 0.73 to 1) as compared with 0.79 (CI95: 0.52 to 0.94) otherwise (P = 0.07). A 300-ml volume expansion induced a ≥2 mmHg increase of central venous pressure, suggesting a change in cardiac preload, in 40 patients, but none of the 28 of 40 nonresponders responded to an additional 200-ml volume expansion.ConclusionsDuring protective mechanical ventilation for early ARDS, partly because of insufficient changes in pleural pressure, ΔRESPPP performance was poor. Careful fluid challenges may be a safe alternative.

Patient-ventilator asynchrony affects pulse pressure variation prediction of fluid responsiveness

“…The rate of fluid responders in our population was 42.5%, a value similar to those reported in previous studies [22,26]. Pulse pressure variation is a valuable dynamic index during CMV under certain conditions [10,11,25,27], but it performs poorly in actively breathing patients [1]. This greatly limits its clinical use because early discontinuation of CMV in favor of forms of partial support is nowadays a cornerstone of the management of ICU patients [28] and PSV is increasingly used, particularly during the weaning process [29].…”

Cardiopulmonary interactions and volume status assessment

“…A practical problem with all the methods based on detection of respirophasic change in SV or its surrogates, is the potential confounding influence of the ventilatory conditions and changes in chest wall and/or lung compliance [43]. These methods do not appear to remain as helpful in the presence of active inspiratory or expiratory effort, [44][45][46], with small tidal volumes [47][48][49], increased abdominal pressure [50], altered chest wall compliance [44], changes in vascular tone or arrhythmias.…”

Accuracy of Stop-Cursor Method for Determining Systolic and Pulse Pressure Variation

“…With lung protective ventilation, the patients generally had a small SPV, which may have indicated fluid nonresponsiveness or reflected the minimal change in intrathoracic pressure. 10,12,13 A strength of the study was that 66% of the patients received tidal volumes less than 8 mL/kg, which is consistent with current practice and enhances the generalizability of the results.…”