P1.003: Challenging Mortality: Successful VA-ECMO in Pediatric Acute Liver Failure with Profound Vasoplegia

Introduction: Pediatric acute liver failure (ALF) from acetaminophen ingestion is well-described. Hemodynamic instability may result from vasoplegia and arrhythmias, leading to circulatory failure. Extracorporeal Membrane Oxygenation (ECMO) for ALF, with both veno-arterial (VA) or veno-venous (VV) cannulation is uncommon, with high mortality rates of greater than 60%.

Case Description: A 16-year-old male with Type 1 diabetes mellitus transferred from an outside institution with ALF secondary to acetaminophen ingestion. Ingestion of an estimated 16,000 mg had occurred approximately thirty-six hours prior to transfer, and he had been managed with N-acetylcysteine therapy. On admission, he had a heart rate of 150 with otherwise age-appropriate vital signs. His labs showed a metabolic acidosis with pH 7.09, HCO3 6, and lactate 11.6 in addition to ALT 5141, AST 998, INR 5.7, and ammonia 16. Within 8 hours, he decompensated significantly with worsened acidemia (pH 6.98, HCO3 < 6, lactate >20) and hepatic function (ALT 8071, AST 18764, INR 10.8, ammonia 209), ultimately requiring intubation. He received norepinephrine and epinephrine for hypotension and started continuous renal replacement therapy. He later had 2 bradycardic arrests requiring chest compressions as well as an episode of supraventricular tachycardia, which converted with adenosine. The patient was placed on VA-ECMO within twenty-four hours of transfer.

The patient remained on VA-ECMO for 9 days and was marginally supported on pump flows of 4-4.5 and sweep flows of 3-5.5. Due to the degree of profound vasoplegia, cyanocobalamin was trialed; however, minimal response was noted. He required atrial septostomy for left atrial decompression on hospital day 3. He continued to have arrhythmias requiring adenosine, lidocaine, and cardioversion before improvement on hospital day 5. He received therapeutic plasma exchange for three days; his liver function improved, and he was de-listed for transplant. He was converted to intermittent hemodialysis on hospital day 32 and eventually transferred to inpatient rehabilitation.

Discussion: Vasoplegia in ALF is a well-known phenomenon, thought to be related to cytokine activation from endotoxins resulting in excess nitric oxide. Vasoconstriction of the microcirculation and arteriovenous shunting results in poor oxygenation of tissues. The use of VA-ECMO contributes to inflammation and vasodilation, making its use in disease states with vasoplegia challenging. Cardiotoxicity from acetaminophen overdose is multifactorial and mechanisms of arrhythmias are poorly characterized. In this case, refractory arrhythmias contributed to hemodynamic instability. While VA-ECMO has been used for pediatric ALF, the rate of recovery is lower than other ECMO populations with 36% survival to hospital discharge.

Conclusion: VA-ECMO use in pediatric ALF remains controversial but may support some patients with severe vasoplegia or hemodynamically significant arrhythmias. Early identification of impending circulatory failure and timely initiation of VA-ECMO may be beneficial for certain patients. A better understanding of which patients will benefit from this therapy may improve outcomes.