subsequent studies have not all been in agreement. Several randomized controlled trials have been unable to reproduce positive results with vasopressin treatment in both return of spontaneous circulation (ROSC) and survival to hospital discharge, including a systematic review and meta-analysis completed in 2005 that found no evidence of a significant difference with vasopressin in five studied outcomes. Vasopressin and epinephrine vs. epinephrine alone There is no current evidence of significant survival benefit with improved neurological outcomes in patients given combinations of both epinephrine and vasopressin during cardiac arrest. A systematic review from 2008 did, however, find one study that showed a statistically significant improvement in ROSC and survival to hospital discharge with this combination treatment; unfortunately, those patients that survived to hospital discharge had overall poor outcomes and many sustained permanent, severe neurological damage. A more recently published clinical trial out of Singapore has shown similar results, finding combination treatment to only improve the rate of survival to hospital admission, especially in the subgroup analysis of patients with longer "collapse to emergency department" arrival times of 15 to 45 minutes. Surgery for congenital heart disease Vasopressin is used in managing hemodynamic instability in newborns and older children recovering from cardiac surgery. There is evidence that some children recovering from cardiac surgery have relative vasopressin deficiency, such that their endogenous plasma concentrations of arginine vasopressin are lower than what would be expected in this clinical setting. Though low endogenous vasopressin concentrations in and of themselves do not cause hemodynamic instability, neonates and children recovering from cardiac surgery who develop hemodynamic instability and have low endogenous vasopressin concentrations are optimal candidates for this surgery. Unfortunately, measurement of endogenous vasopressin concentration is time-consuming and cumbersome, and not practical for bedside application. Copeptin, a more stable and easily measured product of pro-AVP processing, may be a means of identifying patients with low endogenous vasopressin concentrations. Further research is needed. Also, systemic corticosteroids have been shown to suppress endogenous vasopressin production and release. Neonates and children recovering from cardiac surgery who are receiving systemic corticosteroid therapy may also be optimal candidates for vasopressin therapy should hemodynamic instability be present. Vasopressin receptor inhibition A vasopressin receptor antagonist is an agent that interferes with action at the vasopressin receptors. They can be used in the treatment of hyponatremia. References External links Antidiuretics Drugs acting on the genito-urinary system Peptides Vasopressin receptor agonists