Low Dose Dexmedetomidine Attenuates Hemodynamic Response to Skull Pin Holder Application.

BACKGROUND: The application of skull pin holder elicits an adverse hemodynamic response that can be deleterious; there are many drugs that have been used to attenuate this response. We have conducted this study to evaluate the efficacy of intravenous (i.v.) dexmedetomidine on attenuation of hemodynamic responses to skull pin head holder application and to compare the effectiveness of two doses of i.v. dexmedetomidine (1 µg/kg and 0.5 µg/kg bolus). MATERIALS AND METHODS: Ninety American Society of Anesthesiologists physical Status I-III patients undergoing craniotomy were randomized into three groups of thirty each. After intubation, patients in Group A received 1 µg/kg of i.v. dexmedetomidine, Group B received 0.5 µg/kg of i.v. dexmedetomidine, whereas Group C received an equivalent quantity of normal saline. Hemodynamic parameters were monitored regularly after skull pin insertion. RESULTS: There was no significant difference in the monitored hemodynamic parameters among the three groups from baseline until intubation. Heart rate (HR) and mean arterial pressure (MAP) increased significantly at skull pin insertion and subsequent points in Group C, whereas the values decreased in Groups A and B (P < 0.05). Patients in Group A showed a higher and sustained attenuation of MAP. Patients in Group C had a higher incidence of tachycardia and hypertension requiring additional measures to attenuate the response. CONCLUSIONS: Dexmedetomidine in either dosage (1 µg/kg or 0.5 µg/kg) was effective in attenuating hemodynamic response to skull pin insertion. Dexmedetomidine in doses of 0.5 µg/kg was as effective in attenuating the HR and MAP response to skull pin insertion as compared to a dose of 1 µg/kg.

Epidural ropivacaine with dexmedetomidine reduces propofol requirement based on bispectral index in patients undergoing lower extremity and abdominal surgeries.

BACKGROUND AND AIM: To assess the amount of propofol required for induction based on bispectral index (BIS) after administering epidural anesthesia with ropivacaine alone and ropivacaine with dexmedetomidine in patients undergoing lower extremities and abdominal surgeries. SUBJECTS AND METHODS: A double-blinded randomized clinical trial was carried out in 60 patients over a period of 2 years in a tertiary care hospital. American Society of Anaesthesiologists I or II in age group 18-65 years were included in the study. Group R received epidural anesthesia with ropivacaine alone, and Group D received ropivacaine and dexmedetomidine. General anesthesia was induced with propofol under BIS monitoring after 15 min. Onset of sensory and motor block, time for loss of consciousness and total amount of propofol used during induction to achieve the BIS value < 55 were recorded. Student's t-test and Chi-square test were used to find the significance of study parameters. RESULTS: Time of onset of sensory block (Group R 11.30 ± 1.64/Group D 8.27 ± 0.83 min), motor block (Group R 14.16 ± 1.33/Group D 12.63 ± 1.22 min), time for loss of consciousness (Group R 90.57 ± 11.05/Group D 73.67 ± 16.34 s), and total amount of propofol (Group R 129.83 ± 22.38/Group D 92.13 ± 12.93 s) were reduced in Group D which was statistically significant with P < 0.001. CONCLUSION: Epidural ropivacaine with dexmedetomidine significantly reduces the total propofol dose required for induction of anesthesia. Also, it decreases the onset time of sensory and motor block and provides good hemodynamic stability.