The Effect of Adding Ketamine to The Drugs for Induction of Anesthesia on the Cardiovascular Response to the Endotracheal Intubation

This investigation was performed to examine hemodynamic stability for the period of anesthesia induction and intubation, employing thiopental added to fentanyl, thiopental added to ketamine, and thiopental added to fentanyl and ketamine Sixty adult patients were randomly allocated in this randomized clinical trial to one of the three groups according to the drugs used for the induction: thiopental (4 mg/kg) plus to fentanyl (3µg/kg) (TF, n=20), thiopantal plus ketamine (0.1mg/kg) (TK, n=20), or fentanyl (3µg/kg) and ketamine (0.1mg/kg) (TFK, n=20). Hemodynamic responses were evaluated by determining changes in blood pressure (BP) and heart rate (HR) just before laryngoscopy and at 1, 3, 5, and 10 min after that. Throughout the induction of anesthesia BP and HR variations were more in the TK group than that in the TF and TFK groups (p = 0.009). After laryngoscopy, BP significantly increased in the TF and TK groups compared with the TFK group (p=0.027), the rank sequence was TK > TF > TFK. Heart rate was also significantly increased in TK group compared with TF and TFK groups after laryngoscopy (p= 0.013), the rank sequence was TK > TF > TFK. After intubation, BP and HR remained unchanged compared with their preintubation levels in the TFK group. Thiopental added to fentanyl and ketamine caused greater reduction of instabilities in hemodynamic variables throughout the induction of anesthesia and tracheal intubation than thiopental added to fentanyl or thiopental added to ketamine.