The Diving Reflex and Sudden Cardiac Death

But first, why “drenched doc”?  Here’s the connection.  It is from an earlier chapter of my life--my life as an interesting case--an FUO.   We wrote it up. and it was published in the New England Journal of Medicine in 2007.

The Drenched Doctor 

Daniel R. Kaul, M.D., Mark B. Orringer, M.D., Sanjay Saint, M.D., M.P.H., and Stephen R. Jones, M.D.N Engl J Med 2007; 356:1871-1876 May 3, 2007 http://www.nejm.org/doi/full/10.1056/NEJMcps065377

I’ve lived happy and well since the discovery of that tracheal-bronchial fistula by Dr. Frank Baumeister and its surgical resolution by Dr. Larry Eidemiller and Ed Irish.  A important part of my recovery was the care I received in the hospital and at home from Beth.  That’s why at age 72 I was brave enough to go snorkeling.

Cardiac arrest and snorkeling, here’s the consensus of what happened to me.  There is a well-known physiological phenomenon known as the diving reflex.  It is activated when the face is placed in water that is less than 70 F.  This elicits a series of neurologic responses that cause apnea and a decrease in heart rate, sometimes as low as 20% of baseline in extreme responses.  Under normal circumstances, this causes a compensatory increase in blood pressure to insure sufficient circulation to the heart and brain.  However, rather than increase, my blood pressure decreased, likely due to my pre-existing pulmonary hypertension and the medications that I take.  As a result, there was no effective circulation of my blood.

It is likely that the diving reflex partially abated on the way to the pier while Beth supported my circulation with CPR.  My circulation was further normalized by the intravenous infusions that they gave me at the emergency clinic in Zihautanejo. 

The Mexican clinicians, and my cardiologist, Dr Jack McAnulty, made sure that the more usual causes of sudden cardiac arrest did not apply:  pulmonary embolus, or ventricular fibrillation from coronary occlusion.

Since writing my first piece I have talked with several people who have family members with symptomatic slowing of the heart rate when their face is in cool water. 

Background:

1.     http://en.wikipedia.org/wiki/Mammalian_diving_reflex

2.     JAMA. 1965;192(8):25-27. doi:10.1001/jama.1965.03080210089047.

3.     http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2279457

4.     http://www.scientificamerican.com/article.cfm?id=breath-holding-dive-reflex-extends

Our Mexican Vacation--The Day of the Death

Beth and I went on the fifth day of our vacation-- well we went snorkeling.  I put on the fins, the mask and put the the snorkel in my mouth and jumped from the boat.  The water was a pleasant, not cold.  I cleared a little water from the snorkel and replaced it.  Face in the water I paddled to the nearby coral reef.  I saw two or three divers at the reef watching a few fish.

I began to feel light-headed.  I swam back to the boat and asked Alberto, Hector's nephew, for help.  He could not pull me in.  Beth came to me.  I lost consciousness.  Help came, and Beth, Hector, Alberto and two other men pushed and pulled me into the boat.

In the boat Beth found me without detectable pulse or respiration.  I was purple-blue.  She started chest compressions.  After a few minutes she was joined by another woman competent in CPR.

Alberto drove the boat back to the Zihuatanejo Pier while the women continued breaths and compressions.  On the trip back I regained slow ineffective breathing.  An ambulance was waiting.  I was taken to Mediciel Hospitalizacio at 6 Morelos Avenue.  There I awoke to find them infusing saline and dopamine.  I asked Beth repeatedly to tell me what happened.

After air transport to the Real San Jose Hospital's ICU in  Zapopan, Guadalajara, two days later I was flown back to my home ICU, the Kern at Good Samaritan Hospital in Portland, Oregon.  Now ten days after snorkeling I am home.  I am doing OK.  Well, as you see, more than OK!