Treatment of Refractory Hypoxemia in Adults With Acute Respiratory Distress Syndrome-What Is the Available Evidence?

Prone positioning during venovenous extracorporeal membrane oxygenation for acute respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

Prone positioning (PP) improves oxygenation and respiratory mechanics and is associated with lower mortality in patients with moderate to severe acute respiratory distress syndrome (ARDS). Despite this, some patients develop refractory hypoxemia and hypercapnia requiring venovenous extracorporeal membrane oxygenation (VV ECMO) support and are usually cared for in supine position. The physiologic and outcome benefits of routine PP of patients during VV ECMO remains unclear. Hence, we conducted the systematic review and meta-analysis to evaluate the outcome benefits of PP for patients with ARDS being treated with VV ECMO.

METHODS

After registration with PROSPERO (CRD42020199723), MEDLINE, EMBASE, Scopus and Cochrane databases were searched for relevant studies that reported PP in more than 10 adult patients supported with VV ECMO from origin to 1 March 2021. Studies were reviewed for quality using appropriate Joanna Briggs Institute (JBI) checklists, and certainty of evidence was assessed using the GRADE approach. The random-effects model (DerSimonian and Laird) was used. The primary outcome of interest was cumulative survival. Secondary outcomes were intensive care unit length of stay (ICU LOS) and ECMO duration. Changes in arterial blood gas (ABG) values, ventilator mechanics and complication rates were also studied.

RESULTS

Of 812 potentially relevant publications, 12 studies (640 patients) met our inclusion criteria. Due to overlapping study populations, 11 studies were included in the final meta-analysis. Cumulative survival in patients that underwent PP was 57% (95% CI 41.9-71.4, high certainty). Patients that underwent PP had longer ICU LOS (+ 14.5 days, 95% CI 3.4-25.7, p = 0.01) and ECMO duration (+ 9.6 days, 95% CI 5.5-13.7, p < 0.0001). After PP, patients had significantly higher PaO2/FiO2 ratio, lower PaCO2 and reduced ventilator driving pressure, and no major complications were reported.

CONCLUSIONS

PP during VV ECMO appears safe with a cumulative survival of 57% and may result in longer ECMO runs and ICU LOS. However, evidence from appropriately designed randomized trials is needed prior to widespread adoption of PP on VV ECMO.

Extracorporeal membrane oxygenation in pregnancy and the postpartum period: a systematic review of case reports

The use of extracorporeal membrane oxygenation (ECMO) as salvage therapy for patients with severe cardiopulmonary failure has increased significantly in the past decade. However, the use of ECMO in pregnant and peripartum patients has received scant attention. We performed a systematic review of case reports in the literature, documenting indications and outcomes of ECMO in pregnancy and postpartum patients. Case reports on ECMO use in pregnant and postpartum patients were retrieved from MEDLINE, EMBASE and SCOPUS databases up to December 2018. Ninety publications reporting on 97 patients met our inclusion criteria. The majority of publications reported peripartum or postpartum ECMO use for cardiovascular failure (60.8%), while the remainder had respiratory failure. Adult Respiratory Distress Syndrome (91.9%) was the most common respiratory indication while pulmonary embolism (23.7%) and peripartum cardiomyopathy (16.9%) accounted for the two most common cardiovascular indications. Hemorrhage was the most common complication of ECMO reported (31.9%). Of 96 documented neonatal outcomes, 80 neonates (83.3%) survived while 88 of 97 (90.7%) mothers survived. Extracorporeal membrane oxygenation appears to be a viable life support modality in pregnant and postpartum women with severe cardiopulmonary failure, but publication bias in our study cohort should be considered.

Management of fluid status and cardiovascular function in patients with diffuse skin inflammation

Background: Skin inflammation causes vasodilation and increased vascular permeability, which may result in decreased blood pressure and peripheral edema. Patients with erythroderma usually compensate for low blood pressure with fluid retention and increased cardiac output. However, if the heart cannot support increased cardiac output, blood pressure will stay low, resulting in severe compensatory fluid retention, which leads to decompensated congestive heart failure, and pulmonary edema. Treatment for high-output congestive heart failure focuses on the primary pathology, which is skin inflammation. However, aggressive treatment of the inflammation with glucocorticoids may result in rapid resorption of extravascular fluid into the intravascular space and occurrence or aggravation of pulmonary edema. Erythrodermic patients with no clinical heart failure are also at risk for developing pulmonary edema if they receive glucocorticoids and/or intravascular fluids. Most hospitalists and dermatologists are not familiar with fluid administration and ways to manage cardiovascular function and blood pressure in patients with skin inflammation. Objectives and methods: In this article, we discuss the pathophysiology of vascular and fluid changes in the context of diffuse skin inflammation and provide some basic guidelines that can be presented to hospitalists by dermatologists. Limitations: Most of the recommendations and guidelines in the article are based on basic science and on the personal experience of the authors and are not supported by controlled trials. Capsule summary Diffuse skin inflammation causes major changes in the cardiovascular system and in the perfusion of internal organs. We provide guidelines for management of fluid status and cardiovascular function in patients with diffuse skin inflammation. Dermatologists can provide hospitalists or primary care providers with these guidelines to help them with creating better treatment plans.