Letter to the Editor|Articles in Press

Extracorporeal Membrane Oxygenation for Stage 1 Palliation: Early bridge to recovery rather than a late act of pure despair

Published:March 12, 2023DOI:
      To the Editor:
      We appreciate the article by Zaleski et al. as it describes in detail the challenging management of a patient with hypoplastic left heart syndrome (HLHS) undergoing stage I palliation (S1P) - one of the most demanding tasks in cardiac surgery and anesthesiology for congenital heart disease [1]. The course of the young patient presented in their article was uneventful. Nonetheless, internationally reported premature mortality is high at up to 14.3% and remains at 8-11% even in high-volume North American centers, and even after establishing specialized "single-ventricle” teams [2;3].
      European Guidelines advocate early deployment of extracorporeal membrane oxygenation (ECMO), particularly when adequate hemodynamics cannot be achieved with vasopressors and inotropes (class IIa, level C) [3]. Distinct protocols with clear indications for ECMO support have not been outlined yet. A critical situation with multiorgan damage may arise when a mean arterial pressure of 40-50 mmHg cannot be reached despite optimal hemoglobin level (>14 g/L) and escalating inotropic use with epinephrine and milrinone, and efforts to balance pulmonary and systemic perfusion for optimal systemic oxygen delivery fail [1, 3, 4].
      Three parameters appear to indicate severe right (functional) ventricular failure and systemic malperfusion after S1P, which presumably favors early ECMO support. Atrioventricular valve dysfunction was evaluated as the strongest predictor of 1-year mortality after S1P [2]. Systemic venous oxygen saturation (SvO2) sampled in the innominate or superior cava vein below 30% revealed an anaerobic threshold when analyzing acid base changes [5]. A SvO2 less than 45% was associated with a high risk of adverse outcome [6] [Figure 1.]. Regarding lactate level, serum lactate kinetics was a strong predictor of outcome rather than a fixed threshold. An increase in serum lactate of above 0.75 mmol/L per hour or inability for lactate clearance below 6.76 mmol/L within the first postoperative day were considered critical [7;8]. However, it must be kept in mind that, especially in pediatric cardiac surgery patients, serum lactate levels not only reflect inadequate tissue perfusion, but are also influenced by increased glycolysis reflecting a stressed state (type B hyperlactatemia) [9]. Additionally, the metabolic storage burden of transfused red blood cells must be recognized as a contributing factor, particularly in the early perioperative period, even with a short storage time (≤4 days) [10]. Processing circuit volume with cell-saver systems or usage of washed red blood cells attenuates this effect [11].
      Figure 1
      Figure 1Complication risk associated with superior venous oxymetry.
      CPR, cardiopulmonary resuscitation; ECMO, extracorporeal membrane oxygenation.
      We therefore propose that a structured protocol be implemented to assess the need for ECMO support when hemodynamics remain borderline despite efforts to optimize oxygenation and tissue perfusion [11]. In addition to an SvO2 below 45% as the key parameter, significant tricuspid regurgitation and continuously rising serum lactate or failure to lower lactate within the first postoperative day, discussion of preemptively deploying ECMO should precede the collapse of this complex and highly vulnerable hemodynamic state. After initiation of ECMO, once hemodynamics have stabilized and bleeding has stopped, cardiac catheterization should be considered. Since patients with HLHS often have additional complex malformations, residual lesions can be found in a large proportion of patients, and outcomes improve with timely intervention [12].
      Declaration of interests
      The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.


      1. Zaleski KL, Valencia E, Matte GS, et al. How We Would Treat Our Own Hypoplastic Left Heart Syndrome Neonate for Stage 1 Surgery. J Cardiothorac Vasc Anesth. 2023 Jan 8:S1053-0770(23)00001-0. doi: 10.1053/j.jvca.2023.01.003. Epub ahead of print. PMID: 36717315.
      2. Alphonso N, Angelini A, Barron DJ, et al. Guidelines for the management of neonates and infants with hypoplastic left heart syndrome: The European Association for Cardio-Thoracic Surgery (EACTS) and the Association for European Paediatric and Congenital Cardiology (AEPC) Hypoplastic Left Heart Syndrome Guidelines Task Force. Eur J Cardiothorac Surg. 2020;58:416-499.
      3. Pisesky A, Shah S, Seed M, et al. Standardisation of management after Norwood operation has not improved 1-year outcomes. Cardiol Young. 2021; 31:105-113.
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      5. Hoffman GM, Ghanayem NS, Kampine JM, at al. Venous saturation and the anaerobic threshold in neonates after the Norwood procedure for hypoplastic left heart syndrome. Ann Thorac Surg. 2000;70:1515-20.
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      7. Murtuza B, Wall D, Reinhardt Z, et al. The importance of blood lactate clearance as a predictor of early mortality following the modified Norwood procedure. Eur J Cardiothorac Surg. 2011;40:1207-14.
      8. Charpie JR, Dekeon MK, Goldberg CS, et al. Serial blood lactate measurements predict early outcome after neonatal repair or palliation for complex congenital heart disease. J Thorac Cardiovasc Surg. 2000;120:73-80.
      9. Stephens EH, Epting CL, Backer CL, Wald EL. Hyperlactatemia: An Update on Postoperative Lactate. World J Pediatr Congenit Heart Surg. 2020;11:316-324.
      10. Paglia G, D'Alessandro A, Rolfsson Ó, et al. Biomarkers defining the metabolic age of red blood cells during cold storage. Blood. 2016;128:e43-50.
      11. Mills KI, Kaza AK, Walsh BK, et al. Phosphodiesterase Inhibitor-Based Vasodilation Improves Oxygen Delivery and Clinical Outcomes Following Stage 1 Palliation. J Am Heart Assoc. 2016;5:e003554.
      12. Brown KL, Thiruchelvam T, Kostolny M. Extracorporeal membrane oxygenation after the Norwood operation: making the best of a tough situation. Eur J Cardiothorac Surg. 2022;62:ezac221.

      Linked Article

      • How We Would Treat Our Own Hypoplastic Left Heart Syndrome Neonate for Stage 1 Surgery
        Journal of Cardiothoracic and Vascular AnesthesiaVol. 37Issue 4
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          ALTHOUGH NO LONGER UNIFORMLY fatal, hypoplastic left heart syndrome (HLHS) continues to significantly challenge providers across pediatric specialties. This is especially true in the neonatal period when patients with HLHS undergo stage 1 palliative surgery. Despite advances in medical and surgical management, in-hospital and 1-year mortality remain high.1-11 At present, there is limited evidence-based society guidance on the perioperative management of neonates with HLHS undergoing stage 1 palliation.
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