Kenneth L. Smith, Mercer University College of Pharmacy
Vasodilatory shock is a medical emergency where the organs and tissues undergo a decrease in perfusion which can lead to organ failure and death if not treated immediately. In this syndrome, a drop in blood pressure can occur despite preserved cardiac output.  When intravenous fluid resuscitation fails to restore blood pressure, few choices are available other than vasopressors such as catecholamines (or other sympathomimetics) in addition to vasopressin. However, these can be toxic at highdoses, and when these options fail, prognosis is considered poor. Angiotensin II is a component of the renin-angiotensin –aldosterone-system (RAAS) which causes the release of anti-diuretic hormone (ADH), also known as vasopressin, from the posterior pituitary. This leads to vaso-constrictive effects that can increase blood pressure. Consequently, use of angiotensin II for vasodilatory shock has been considered to provide a more natural physiological response to treat this serious condition.
|Angiotensin II for the Treatment of Vasodilatory Shock [5 ]|
|Design||International, randomized, double-blind, placebo-controlled trial|
|Objective||To measure the effectiveness of angiotensin II for the treatment
of patients with vasodilatory shock
|Study Groups||Angiotensin II (N = 163) and Placebo (n = 158)|
|Methods||A response as, included in the primary endpoint, was defined as a mean arterial pressure of 75 mm Hg or higher or an increase in mean arterial pressure from baseline of at least 10 mm Hg, without an increase in the dose of background vasopressors. Patients had to have vasodilatory shock despite intravenous volume resuscitation. Vasodilatory shock was defined as a cardiac index > 2.3 liters/min●m2 or central venous oxygen saturation of >70% coupled with a central venous pressure of more than eight mmHg with a mean arterial pressure between 55-70 mmHg. Eligible patients in the study had an indwelling bladder catheter and an arterial catheter.|
|Duration||May 2015 through January 2017|
|Primary Outcome Measure||the response with respect to mean arterial pressure at hour three|
|Adverse Events||Common Adverse Events: N/A|
|Serious Adverse Events (defined as frequency ≥1%):
cardiovascular events (38.3%), metabolism and nutrition disorders (29.9%), infections and infestations (24.6%), vascular disorders (23.1%), Respiratory, thoracic and mediastinal disorders (24.9%), gastrointestinal disorders (21.8%), blood and lymphatic disorders (16.5%), psychiatric disorders (10%)
|Percentage that discontinued due to adverse events:|
|Study Author Conclusions||Angiotensin II was demonstrated to effectively increase blood pressure in patients with vasodilatory shock that failed to respond to high doses of conventional vasopressors.|
The study was only carried out for 28 days, which may risk the possibility of not addressing long term effects that may be associated with angiotensin II treatment. Another limitation of the study was the small sample size which may have excluded the possibility of other clinical side effects attributable to angiotensin II treatment. A larger study that includes more patients for a longer duration would provide more meaningful information about adverse effects and potential long term side effects due to treatment with this drug. Due to the positive results in this study, angiotensin II does appear to be a valuable treatment option for vasodilatory shock in patients that are resistant to other vasopressors.
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