Cardiac Arrest

Highlights :

Cardiac Arrest

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Thursday, 10 December 2009 10:02

Cardiac Arrest

¦Definition: Sudden failure of the heart to pump blood.
¦Causes:
(A) Failure of the heart to pump (Myocardial depression) by:
1-Myocardial hypoxia as a result of:
w Respiratory obstruction by aspirated vomitus may cause reflex inhibition .
w Coronary occlusion e.g. air embolism.
w Sudden drop of blood pressure e.g. sudden severe haemorrhage.
2- Metabolic causes e.g. hyperkalemia leads to heart arrest in diastole. This fact is used in preparation of cardioplegic solutions used in cardiac surgery.
3- Diseased myocardium can not withstand moderate hypoxia.
4- Drug induced e.g. Some anaesthetic agents, inotropic drugs, B blockers, calcium antagonists and other vasodilators.
5- Hypothermia.
(B) Failure of the heart to fill as in :
1- Vascular obstruction by massive pulmonary embolism.
2- Cardiac tamponade.
¦Types of arrest:
1- Asystole : The heart will be Flappy, Dilated and Cyanosed
2-Ventricular fibrillation : Very rapid frequent contractions not allowing the ventricle to refill.
3- Circulatory obstruction:By Massive pulmonary embolism or air embolism.
¦Diagnosis:
1- No pulse in big vessels as femorals and carotids .
2- Signs of cerebral hypoxia r Unconsciousness.
r Apnea with or without cyanosis.
r Widely dilated pupils.
Diagnosis must be done within 5 minutes otherwise irreversible brain damage will occur. After 5 minutes, even if treatment is done and heart beats regained, the patient will be decerebrated.
¦ Treatment :
(a) Emergency phase: (Carried out by the person on the spot)
1- Mouth to mouth breathing .
2- Closed cardiac massage. Done by compression with both hands over the lower sternum at rate of 10 chest compressions to one breathing this more efficiently carried out by two persons. Simple blow to the chest may result in return to sinus rhythm from VF.
If performed efficiently it can maintain blood supply to vital centers for several hours until the emergency care come and the patient is transferred to hospital .

(b) At the hospital:
1-At the earliest moment an endotracheal tube should be passed and positive pressure ventillation started.
2- Venous access as soon as possible for drug administration.
3- Electrocardiographic monitoring to detect the type of arrest

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External cardiac massage

and mouth to mouth breathing

Thoracotomy Press againest sternum

Internal cardiac massage

Open cardiac massage

Through Lt. 5th intercostal space thorocotomy:
Massage the heart with flat of the hand against back of the sternum at a rate of 5o/ minute.
w If the heart gets smaller, contracted, red in colour
Œ treat the cause correct acidosis by Na Hco3 and
Ž treat the complications as brain oedema, renal failure or Fracture rib.
w If it persist flappy and cyanosed it will be hopeless.
SOURCE: Prof. AYMAN SALEM'S BOOK
Copyright: (Vascular Society of Egypt ) & (Medical Educational web)
Not to be reproduced without permission of Vascular Society of Egypt