Potential Effects of Corticosteroids on Physiological Dead-Space Fraction in Acute Respiratory Distress Syndrome

Abstract

BACKGROUND: Increased dead-space fraction is common in patients with persistent acute respiratory distress syndrome (ARDS). We evaluated the changes in the oxygenation and dead-space fraction in patients with persistent ARDS after corticosteroid therapy. METHODS: This was a non-randomized non-placebo, controlled observational study including 19 patients with persistent ARDS treated with corticosteroids. We measured P aO 2 /F IO 2 and dead-space fraction at days 0, 4, and 7 after corticosteroids treatment (methylprednisolone) initiation. Patients were classified in intermediate group when corticosteroids were initiated between days 8 -14 after ARDS onset, and in late group when initiated after 14 days. RESULTS: Mean time from the diagnosis of the ARDS to methylprednisolone treatment was 11 ؎ 2 days in the intermediate group (10 patients) and 21 ؎ 8 days in the late group (9 patients). When comparing days 0, 4, and 7 after methylprednisolone treatment, we found an increase in the P aO 2 /F IO 2 (145 ؎ 64 mm Hg, 190 ؎ 68 mm Hg, and 226 ؎ 84 mm Hg, respectively, P < .001) and a decrease in the physiological dead-space fraction (0.66 ؎ 0.10, 0.58 ؎ 0.12, and 0.53 ؎ 0.11, respectively, P < .001). No differences were found between the intermediate and late groups. CONCLUSIONS: In patients with persistent ARDS, the increase in oxygenation was accompanied by a decrease in the dead-space fraction after a few days of corticosteroid treatment. To confirm potential benefit of corticosteroids on physiological parameters and mortality will require a powered randomized placebo controlled trial.

Increased respiratory dead space could associate with coagulation activation and poor outcomes in COVID-19 ARDS

“…These reports show the relationship between coagulation activation and respiratory dead space. As mentioned above, the interplay between inflammation and hemostasis has been well described, and on this basis, in ARDS patients treated with corticosteroids, a reduction in respiratory dead space has been reported [ 30 ]. Therefore, our finding of an association between increased respiratory dead space and D-dimer supports the hypothesis that vascular pulmonary disease is a relevant issue in critically ill COVID-19 patients.…”

Prescribing Patterns of Drugs in Acute Respiratory Distress Syndrome (ARDS): An Observational Study

“…So, corticosteroids in high doses for a short period are proposed in the early phase of ARDS for quick resolution and to prevent progression to lung fibrosis. Methylprednisolone administered to patients with intermediate and late ARDS is associated with improved oxygenation and reduced dead space to tidal volume ratio as early as four days following initiation [13]. In a prospective, randomized trial of methylprednisolone therapy which included 99 patients the investigators concluded that the outcome was not affected in patients with ARDS receiving highdose methylprednisolone [14].…”

Prone position: how understanding and clinical application of a technique progress with time

“…If the balance between these two opposite phenomena favors an overall decrease of ventilation/perfusion ratio, the CO 2 clearance increases and therefore the P a CO 2 decreases. This has been associated to greater survival [24,25]. In contrast, if poor alveolar recruitment occurs (i.e., the dorsal recruited pulmonary units are fewer than the ventral collapsed ones), the upright diversion of the ventilation may lead to an increase of the dead space fraction.…”