It is estimated that nearly 325,000 people in the US die each year from a cardiac arrest. That means that cardiac arrest kills one person every two minutes. It is also estimated that nearly 200,000 cardiac arrests occur while the patient is being treated in the hospital – in-hospital cardiac arrest.

It has been demonstrated in experimental studies that female hormones, primarily estrogen and progesterone, exhibit a neuroprotective effect in animal models of global hypoxic-ischemic injury, stroke and traumatic brain injury.

So, does it mean that female patients, who naturally have higher levels of these hormones, do better after cardiac arrest?

A study by Topjian et al. attempts to answer this question. The authors of this study looked at the survival after an in-hospital cardiac arrest in two groups of patients. Female patients 15-44 years old were compared to the male patients of the same age. Females older than 56 years were compared to the males of the same age group.

The authors hypothesized that female patients of child bearing age will have a significantly higher levels of estrogen and progesterone compared to the male subjects of the similar age. This difference in hormone composition would dissipate after the menopause. Women older than 56 years would not have this advantage over older men. Women between 45 to 55 years were intentionally excluded from this study. The variability of hormonal composition in the perimenopausal period could potentially skew the results.

The findings of this study were quite revealing. After adjusting for confounding conditions, women of child bearing age (15 to 44 years) were more likely to survive to hospital discharge after a cardiac arrest than men in the same age group. Also, younger women had a more favorable neurological recovery compared to men.

In contrast, there was no difference in survival and recovery between men and women older than 56 years.

The authors concluded that administration of female sex hormones might improve the survival after a cardiac arrest. It is unclear if these hormones would have a similar effect in men. No clinical studies investigating the effect of female sex hormones after cardiac arrest have been published.

Interestingly, the improvement in survival exceeded that of any recently introduced advance in health care and treatment after cardiac arrest.

The treatment approach for the victims of cardiac arrest is unlikely to change based on the results of the single study. More evidence is needed before it can be introduced into the clinical practice. Yet, it does sound promising.