Monday, March 26, 2012
78 minutes is a long time to be dead. Thousands of people witnessed Fabrice Muamba collapse dead in the middle of a soccer game. Paramedics rushed to his side and immediately started CPR and for 78 minutes they pressed on his chest and breathed for him on the field, in the ambulance and in the ER. Muamba’s heart was in ventricular fibrillation, a chaotic electrical rhythm where heart muscle cells are bombarded by electrical signals and there is no coordinated contraction to pump blood to the brain and rest of the body. The best chance of surviving is being shocked. 14 times, Muamba’s heart was shocked with no change in the electrical chaos, but with the fifteenth shock, the electrical signals aligned, the muscles squeezed together and Muamba’s heart started to beat.
Dead is a fluid concept. Dead is official when a police officer, medical examiner, coroner or physician declares the patient dead. This is often a frightening prospect for medical students and interns who fear that a patient declared dead will start breathing again. In ancient societies, families watch over a dead relative for days to make certain death was permanent. And then there is brain death, where the body functions normally from the neck down but all brain function has stopped. This different philosophy of death is relatively recent and most important to those in the transplant medicine including the organ procurement personnel, the transplant surgeon, those on the organ waiting list and of course, the family of the brain dead patient. Every other cause of dead occurs when the patient’s heart stops beating.
Cardiac arrest is different than a heart attack or myocardial infarction. With an MI, one of the blood vessels blocks off and the part of the heart muscle that it supplies dies. Heart muscle that loses its blood supply also gets very irritable and can cause the onset of ventricular fibrillation or cardiac arrest. The heart stops beating and the patient dies.
The heart can stop beating in different ways. It can stop with asystole where no electrical activity can be detected and little can be done to restart it. Even pacemakers tend to fail. The heart can stop because of pulseless electrical activity, where the electrical system works but it is disconnected from the heart muscle and no beat is generated. The treatment for this is looking for the underlying problem and fixing it. The problems tend to be bad like shock, collapse of the lung, buildup of fluid in the sac that surrounds the heart, very low body temperature, poisoning and abnormal potassium levels. Survival is rare. The best hope of surviving dead is having ventricular fibrillation since defibrillation (AED, everybody clear…shock) can change electrical chaos into a normal heart beat. And all V fib is not created equal. Coarse V Fib has lots of electrical activity and perhaps is more easily shockable while fine V Fib has less and isn’t.
For Muamba, the big question is why CPR was continued for 78 minutes and not stopped well before the 15th shock. Sometimes, shocks convert the heart into a beating rhythm but the effect doesn’t last but for a minute or two and V Fib returns. The temporary success spurs hope that another minute of two might yield success. Sometimes, it’s the patient. When an infant or child arrives in cardiac arrest, paramedics, doctors and nurses spend forever hoping to make dead go away. Kids who die cut to close to everybody’s heart and nobody wants to stop trying.
After 78 minutes, a strong heartbeat, a normal blood pressure and spontaneous breathing. Many hours later, the docs allow him to waken, remove the ventilator and watch while he opens his eyes, recognizes family and asks about his son. Dead is a fluid concept. Sometimes it ends with a miracle.