The Right Ventricle in ARDS

A novel risk score for severe ARDS patients undergoing ECMO after retrieval from peripheral hospitals

BACKGROUND

Extracorporeal Membrane Oxygenation in severe ARDS unresponsive to conventional protective ventilation is associated with elevated costs, resource and complications, and appropriate risk stratification of candidate patients could be useful to recognize those more likely to benefit from ECMO. We aimed to derive a new outcome prediction score for patients retrieved by our ECMO team from peripheral centers, including systematic echocardiographic evaluation before ECMO start.

METHODS

Sixty-nine consecutive patients with refractory ARDS requiring ECMO transferred from peripheral centers to our ICU (a tertiary ECMO referral center), from 1 October 2009 to 31 December 2015, were assessed.

RESULTS

All patients were transported on ECMO (distance, median 77, range 4-456 km) The mortality rate was 41% (28/69). Our new risk score included age ≥ 42 years, BMI < 31 kg/m² , RV dilatation, and pH < 7.35. The proposed cut off (Youden's index method) of nine had a sensitivity of 96% and a specificity of 30% (AUC-ROC: 0.85, 95% CI: 0.76-0.94, P < 0.001). When assessing the discriminatory ability of our risk score in the population of local patients, survivors had a mean value of 15.4 ± 8.6, whereas non-survivors showed a mean value of 20.1 ± 7.4 (P < 0.001).

CONCLUSIONS

Our new risk score shows good discriminatory ability both in patients retrieved from peripheral centers and in those implanted at our center. This score includes variables easily available at bedside, and, for the first time, a pathophysiologic element, RV dilatation.

Acute Right Ventricular Dysfunction in Intensive Care Unit

The role of the left ventricle in ICU patients with circulatory shock has long been considered. However, acute right ventricle (RV) dysfunction causes and aggravates many common critical diseases (acute respiratory distress syndrome, pulmonary embolism, acute myocardial infarction, and postoperative cardiac surgery). Several supportive therapies, including mechanical ventilation and fluid management, can make RV dysfunction worse, potentially exacerbating shock. We briefly review the epidemiology, pathophysiology, diagnosis, and recommendations to guide management of acute RV dysfunction in ICU patients. Our aim is to clarify the complex effects of mechanical ventilation, fluid therapy, vasoactive drug infusions, and other therapies to resuscitate the critical patient optimally.