Prognostic Factors of Dunn et al for Predicting Survival to Hospital Discharge Following a Cardiac Arrest Associated with Ventricular Fibrillation

 

Patient selection: The age of the patients was not provided. There appears to have been 125 patients, with 63% male.

 

Parameters associated with favorable outcome from the initial arrest:

(1) time from onset of ventricular fibrillation to first shock

(2) number of shocks to convert from ventricular fibrillation

(3) previous antiarrhythmic therapy

(4) etiology of ventricular fibrillation

 

Parameters associated with favorable outcome from the last arrest:

(1) number of previous cardiac arrests

(2) number of shocks to convert from ventricular fibrillation

(3) previous antiarrhythmic therapy

(4) etiology of ventricular fibrillation

Parameters	Finding	Points
number of previous arrests	>= 1	0
	0	1
number of shocks required to convert	<= 5	1
	>= 6	0
previous antiarrhythmic therapy	none	1
	any	0
etiology of ventricular fibrillation	secondary	0
	primary	1

 

where:

• Secondary causes of ventricular fibrillation included myocardial infarction, ischemic heart disease, congestive heart failure, head trauma, hypokalemia, prolonged QTc, cardiomyopathy, pulmonary embolism, and carcinoma of the lung.

• For the parameters associated with the initial arrest, the common parameters are scored the same. The time from onset of the ventricular fibrillation to first shock was scored 1 if < 1 minute and 0 if >= 1 minute.

• A person having only 1 arrest would meet the criteria for both groups.

 

number of favorable risk factors at last arrest =

= SUM(points for all 4 parameters)

 

Interpretation:

• minimum number of favorable factors: 0

• maximum number of favorable factors: 4

• The higher the number of favorable risk factors, the more likely the patient was to survive to hospital discharge.

• The authors did not provide specifics for mapping the prognostic score to probability of survival.

 

Performance:

• For the parameters from the last arrest, the sensitivity was 77% and specificity 75%.

• For the parameters from the initial arrest, the sensitivity was 59% and specificity 89%.