Authors: Nicholas Houska, DO - University of Colorado - Children’s Hospital Colorado
A 2-year-old child with decompensated heart failure and multi-organ dysfunction secondary to myocarditis is placed on veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) via neck cannulation. Four hours after initiation of ECMO, the patient has increasing airway pressures and pink frothy secretions with tracheal suctioning. Transthoracic echocardiography shows severely diminished biventricular dysfunction, lack of aortic valve excursion, and a distended left atrium. Which of the following interventions is the BEST course of action?
EXPLANATION
Extracorporeal membrane oxygenation (ECMO) is increasingly utilized as a therapy in children with severe cardiovascular and/or pulmonary dysfunction. However, it is not without adverse effects on the heart, lungs and other organ systems. In cases of cardiac failure, one of the primary goals of ECMO is to facilitate myocardial recovery, which can be hindered by the physiologic effects of ECMO itself. Specifically, ECMO can increase left ventricular (LV) afterload, thus increasing LV volume and pressure and simultaneously decreasing transmural myocardial perfusion. These untoward effects can inhibit cardiac recovery. Further adverse effects are seen in severe cardiac dysfunction in which the LV is not able to generate enough pressure to open the aortic valve and eject blood. In such cases, left atrial (LA) and pulmonary venous hypertension will be the end result. Pulmonary venous hypertension can lead to pulmonary edema, pulmonary hemorrhage, and impaired gas exchange, which may further delay separation from mechanical support. Stasis of blood in the left ventricle due to lack of aortic valve opening increases the risk of thrombosis, which may be difficult to prevent and treat with typical anticoagulants.
In cases where there is either clinical or echocardiographic evidence of left atrial hypertension, decompression may be indicated to reduce further cardiopulmonary complications. Decompression of the left atrium can be achieved through a variety of methods. In cases of central cannulation, a surgical LA vent may be feasible. Balloon atrial septostomy is an alternative option to achieve LA decompression in cases of peripheral ECMO cannulation or complex anatomy circumventing surgical LA vent placement. This is most commonly achieved percutaneously in the cardiac catheterization lab or bedside with echocardiographic guidance. More recently, temporary ventricular assist devices, such as the Impella, have been used to decompress the left ventricle and atrium. A retrospective study by Sperotto and colleagues demonstrated that 279 (18%) out of a total of 1,508 children with biventricular physiology required LA decompression during VA ECMO support due to failure to wean from cardiopulmonary bypass. This study also demonstrated that LA decompression was protective against in hospital adverse events. Further studies investigating the risk/benefit profile of LA decompression during ECMO support in children are warranted.
Diagnostic bronchoscopy may temporarily improve pulmonary function by clearing secretions but does not address the underlying problem. Similarly, increasing ECMO flows is likely to worsen LA hypertension by further increasing left ventricular afterload, and therefore, is not beneficial.
REFERENCES
Sperotto F, Polito A, Amigoni A, Maschietto N, Thiagarajan RR. Left atrial decompression in pediatric patients supported with extracorporeal membrane oxygenation for failure to wean from cardiopulmonary bypass: a propensity‐weighted analysis. J Am Heart Assoc . 2022;11(23):e023963.
Bhaskar P, Davila S, Hoskote A, Thiagarajan R. Use of ECMO for cardiogenic shock in pediatric population. J Clin Med . 2021;10(8):1573.
Brown G, Moynihan KM, Deatrick KB, et al. Extracorporeal life support organization (ELSO): guidelines for pediatric cardiac failure. ASAIO J. 2021;67(5):463-475.
