Case report: veno-venous ECMO as a bridge to lung transplantation in paraquat poisoning

September 9, 2015, 1:49 am

Paraquat
★★★☆☆

Successful extracorporeal membrane oxygenation therapy as a bridge to sequential bilateral lung transplantation for a patient after severe paraquat poisoning. Tang X et al.  Clin Toxicol 2015 Aug 28 [Epub ahead of print]

Abstract

Conceptually, extracorporeal membrane oxygenation (ECMO) seems a perfect technique for treating some of the sickest toxicology patients,  buying time until failing vital functions can recover.

With severe cardiotoxins — for example, calcium channel blockers, beta blockers or bupropion — veno-arterial ECMO can provide complete cardiopulmonary bypass, replacing both cardiac and pulmonary function.

In the case of severe poisoning with paraquat — a highly toxic herbicide that causes progressive respiratory failure and irreversible pulmonary fibrosis — veno-venous ECMO can replace support pulmonary function and serve as a bridge to lung transplantation.

This paper from Beijing Chao-Yang Hospital describes what is, to my knowledge, the first case in which v-v ECMO has been used successfully to treat paraquat poisoning. A 24-year-old, 53-kg woman ingested an estimated 50 ml of 20% paraquat.She arrived at hospital 2 hours later and was initially treated with gastric lavage, laxatives, and activated charcoal. Additional treatment included cyclosphophamide, steroids, and hemoperfusion. Unfortunately, her initial signs and symptoms are not well-described.

Three days after presentation, the patient was transferred 1500 km to a tertiary clinical poison center in Beijing.  Her hospital course included progressive pulmonary fibrosis and bilateral pneumothoraces requiring intubation and mechanical ventilation on day 34. Despite this, oxygenation continued to decrease and v-v ECMO was started on day 44, and continued until bilateral sequential lung transplantation was accomplished on the 56th day. The authors report that the patient was extubated 10 days after surgery, discharged from hospital 2 weeks later and was doing well at one-year follow-up despite some residual restrictive lung disease.

This interesting report of an exceedingly complex case would have been more useful had much more detail been provide. How did the patient present and what were the initial manifestations of toxicity? What was the initial paraquat level? (In fact, no level was obtained until day 46.) How did the clinical team deal with the very difficult issue of psychological rehabilitation? (The paper suggests that psychological counseling and citalopram were initiated on about day 45 or 46. Since the patient was intubated at that time, this hardly seems credible.)

Finally, the authors speculate that lung transplantation after paraquat poisoning may be more successful if performed later rather than earlier, when the residual paraquat load is as low as possible.

My guess would be that we won’t see many case reports similar to this one. Paraquat poisoning is primarily a problem in developing countries, where the fortuitous confluence of the availability of ECMO, the ability to perform lung transplant, and facilities for psychological rehabilitation must be exceedingly rare.

To read my Emergency Medicine News column on ECMO in the poisoned patient, click here.

Several months back, Steve Aks and I discussed the potential use of ECMO in the critical toxicology patient with Joe Bellezzo, Zack Shinar and Scott Weingart  from the ED ECMO website. To listen to that podcast, click here.

Related posts

Poisoned patients treat with ECMO: 10 cases from the ToxIC Registry

Lipid rescue therapy and ECMO in the poisoned patient: can they be used together?

ECMO and the poisoned patient: ready for prime time?

 

 

 

 

 

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