Hemodynamic Effects of Bolus of Ketamine Versus Fentanyl in Patients With Septic Shock

Ketamine is a commonly used drug for sedation and induction of anesthesia in patients with shock and/or cardiac dysfunction. Ketamine is characterized by its cardiovascular stimulatory effect due to increase release of endogenous catecholamines. On the other hand, laboratory data on the isolated human myofibers suggest that ketamine had a direct myocardial depressive effect; accordingly, many experts believe that ketamine might have a negative hemodynamic effect in catecholamine depleted patients such as critically ill patients. In critically ill patients, there are contradicting results for the effect of ketamine on the hemodynamic profile and there is paucity of clinical data about the effect of ketamine on cardiac contractility and cardiac output (CO). Cardiac output is the primary determinant of global oxygen delivery to organs and maintaining stable CO in critically ill patients is at most importance to avoid further organ damage in such patients. Therefore, this study is designed to evaluate the effect a single bolus of ketamine on CO in patients with septic shock in comparison to fentanyl bolus.