Addendum

Letters to the Editor Extracorporeal Cardiopulmonary Resuscitation—Evidence and Implications by Dr. med. Christopher Gaisendrees, Dr. med. Jan-Steffen Pooth, PD Dr. med. Maximilian Luehr, Prof. Dr. med. Anton Sabashnikov, Prof. Dr. med. Demetris Yannopoulos, and Prof. Dr. med. Thorsten Wahlers in issue 42/2023

The article (1) does not mention several important indications for extracorporeal cardiopulmonary resuscitation. These include resuscitation of hypothermic patients—for example, patients who drowned in cold water (in this scenario, asystole is most common)—and patients with severe pulmonary embolism (often with pCO2<10 mm Hg). These two indications are not considered on the basis of the selection criteria of the Extracorporeal Life Support Organization that were suggested in the article (1).

Unfortunately, the importance of randomized controlled trials and other statistical methods has a too prominent position in scientific discourse. This review article too considered only statistical analyses and no case reports. Confirmation of the superiority of a new treatment method in a randomized—ideally—double blind trial provides a very strong indication that a new method is effective. But especially for rare results it is difficult to include sufficiently high numbers of cases in a study. When considering the effectiveness of extracorporeal resuscitation, the following deliberations may be entertained, as generated from pathophysiology:

Resuscitation can be successful only if

• The cardiac arrest has an underlying case that can be reversed with treatment
• Injury to the brain and myocardium does not prevent long-term survival in the time to “return of spontaneous circulation” (ROSC).

Extracorporeal resuscitation makes sense if remedying the cause of the cardiac arrest takes a long time, such as in severe hypothermia of pulmonary embolism. In these cases extracorperal resuscitation has fewer side effects and is more effective than thorax compression. If extracorporeal membrane oxygenation (ECMO) can be applied/administered quickly it should be possible to save some patients with pulmonary embolism.

DOI: 10.3238/arztebl.m2023.0280

Reiner Klick

Anästhesieabteilung Marienkrankenhaus Schwerte

Conflict of interest statement

The author declares that no conflict of interest exists.

The authors of the article have chosen not to publish a reply.

References

1. Gaisendrees C, Pooth JS, Luehr M, Sabashnikov A, Yannopoulos D, Wahlers T: Extracorporeal cardiopulmonary resuscitation—evidence and implications. Dtsch Arztebl Int 2023; 120: 703–1