Pharmacologic agents for acute hemodynamic instability: Recent advances in the management of perioperative shock- A systematic review

Abstract

Despite the growing body of evidence evaluating the efficacy of vasoactive agents in the management of hemodynamic instability and circulatory shock, it appears no agent is superior. This is becoming increasingly accepted as current guidelines are moving away from detailed algorithms for the management of shock, and instead succinctly state that vasoactive agents should be individualized and guided by invasive hemodynamic monitoring. This extends to the perioperative period, where vasoactive agent selection and use may still be left to the discretion of the treating physician with a goal-directed approach, consisting of close hemodynamic monitoring and administration of the lowest effective dose to achieve the hemodynamic goals. Successful therapy depends on the ability to rapidly diagnose the etiology of circulatory shock and thoroughly understand its pathophysiology as well as the pharmacology of vasoactive agents. This review focuses on the physiology and resuscitation goals in perioperative shock, as well as the pharmacology and recent advances in vasoactive agent use in its management.

Factors Affecting Cardiovascular Physiology in Cardiothoracic Surgery: Implications for Lumped-Parameter Modeling

“…Vasopressin, also known as “antidiuretic hormone,” is stored in the pituitary gland and released after hypotension or pain stimulus, and leads to vasoconstriction, consequently increasing SVR (29). It is not associated with the adverse effects of adrenergic agents, and enables an increase in MAP without adversely affecting CO (33). Another agent used to increase SVR is methylene blue.…”

“…This reduces the responsiveness of vessels to vasodilators such as NO (34). Both vasopressin and methylene blue can be used to reverse vasoplegia, however methylene blue is recommended as a strategy of last resort (33).…”

“…* The ‘/' denotes differences between effects at low vs. high dosages. Typical dosages can be found in Morozowich and Ramakrishna (33) and Hollenberg (32) .…”

Methylene blue is not a pure vasoconstrictor drug

“…MB blocks the cyclic guanosine monophosphate (cGMP) pathway through a “cross-talk” mechanism, thereby facilitating the cyclic adenosine monophosphate-dependent epinephrine vasoconstrictor effect. In an excellent systematic review of pharmacologic agents for acute hemodynamic instability, Morozowich and Ramakrishna included MB as a “pure vasoconstrictor” and mentioned “an passant” that the MB use is justified as “rescue therapy.”[1]…”

Role of simulation in hemodynamic monitoring in cardiac surgery

“…By providing a surrounding mimicking both the standardized process and dynamic crisis, high-fidelity simulation improves active memorization and enhances appropriate behaviors in real life while sparing patients from potential harm. [ 8 ]…”