• 
• 

Three Part Question

In [cardiac resuscitation] is [vasopressin more effective than adrenaline] at achieving [return of spontaneous circulation and longterm survival]?

Clinical Scenario

A 67 year old man has been brought into the emergency department by paramedic ambulance. He was initially in ventricular fibrillation, but now has pulseless electrical activity. He collapsed 15 minutes ago and received immediate bystander basic life support. You wonder whether intravenous vasopressin would be better than adrenaline in this situation.

Search Strategy

Medline 1966-01/04 using the OVID interface.
[(exp vasopressins OR vasopressin.mp OR ADH.mp OR antidiuretic hormone.mp) AND (exp epinephrine OR epinephrine.mp OR adrenaline.mp) AND (exp resuscitation OR exp cardiopulmonary resuscitation OR exp Heart arrest OR arrest.mp OR exp ventricular fibrillation OR VF.mp OR ventricular fibrillation.mp OR asystole.mp OR EMD.mp OR electromechanical dissociation.mp OR PEA.mp OR pulseless electrical activity.mp)] LIMIT to human AND English.

Search Outcome

Altogether 47 papers were found, only 3 papers compared the effects of adrenaline and vasopressin.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Lindner KH et al, 1997, Germany	40 pre-hospital VF arrests Randomised to receive either initial dose vasopressin (40u) or adrenaline (1mg)	Prospective randomised double-blind trial	GCS on discharge	10.7 adrenaline vs 11.7 vasopressin	Only looked at VF Small patient sample All out of hospital arrests with mean emergency team response times of 6 minutes
			Spontaneous circulation on admission to hospital	35% adrenaline vs 70% vasopressin (p=0.06)
			Survival to discharge	15 % adrenaline vs 40 % vasopressin (p=0.16)
			24 hour survival	20% adrenaline vs 60 % vasopressin (p=0.02)
			Restoration of spontaneous circulation	55% Adrenaline vs 80% vasopressin patients (p=0.18)
Stiell IG et al, 2001, Canada	200 patients treated for cardiac arrest in three hospitals. Randomised to receive either initial dose vasopressin (40U) or adrenaline (1mg).	Prospective randomised double-blind trial	Survival to discharge	Vasopressin 12%, adrenaline 14%	Powered only to show a 20% difference in 1 hour survival
			Presence of pulse and BP for one hour post resuscitation	Vasopressin group 39% Adrenaline group 35%(not significant)
			Neurological function at discharge	No difference between groups
			30 day survival	No difference between groups
Wenzel et al, 2004, European resuscitation council	589 patients with out-of-hospital cardiac arrest randomised to receive 40IU IV vasopressin x 2 and 597 patients randomised to receive 1mg adrenaline IV. Conducted in three countries	RCT	Restoration of circulation	No significant difference	4748 out of 5967 patients with out-of-hospital cardiac arrest were not randomised The study was powered to show a 25% improvement in outcome. Evidence of a smaller benefit would require a much larger study
			Survival to hospital	No significant difference
			Survival to discharge from hospital	No significant difference
				When subgroups analysed, significantly more patients in asystole survived to hospital 76/262 vs 54/266 p = 0.02 after vasopressin administration. The difference in survival to discharge was not statistically significant Of those who went on to require additional adrenaline doses, all three outcomes were better in the vasopressin group and the difference was significant

Comment(s)

Although vasopressin has been shown to improve survival in a subset of cardiac arrests as yet there is no proven difference in overall outcome. Larger studies are required to prove a benefit of less than 25% increased survival.

Clinical Bottom Line

Vasopressin is as efficacious as adrenaline in cardiac arrest.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Lindner KH, Dirks B, Strohmenger H, et al. Randomised comparison of epinephrine and vasopressin in patients with out-of-hospital ventricular fibrillation. Lancet 1997;349:535-37.
2. Stiell IG, Hebert PC, Wells GA, et al. Vasopressin versus epinephrine for inhospital cardiac arrest: a randomised controlled trial. Lancet 2001;358:105-9.
3. Wenzel V, Krismer A, Arntz R, et al. A comparison of vasopressin and epinephrine for out-of-hospital cardiopulmonary resuscitation. N Eng J Med 2004;350(2):105-113.