Intrathecal Dexmedetomidine and Fentanyl as Adjuvant to Bupivacaine on Duration of Spinal Block in Addicted Patients

Abstract

Background:Addicted patients have innate tolerance to local anesthetics in both neuraxial and peripheral blocks. Dexmedetomidine (Dex) is a highly selective α2 adrenergic receptor agonist used as additive to increase quality and duration of peripheral nerve blocks.Objectives:The current study aimed to compare the effect of dexmedetomidine and fentanyl additives on bupivacaine to prolong the duration of block and minimizing side effects.Patients and Methods:Patients were candidates for elective surgery less than three hours of lower abdomen or lower extremities surgeries. Patients were randomly allocated to receive dexmedetomidine 5 µg added to 12.5 mg (2.5 mL) of 0.5% hyperbaric bupivacaine (DEX group), or 25 µg (0.5 mL) fentanyl added to 12.5 mg (2.5 mL) of 0.5% hyperbaric bupivacaine (F group) or only 12.5 mg of 0.5% hyperbaric bupivacaine. Data were recorded based on sensory block. Motor block was tested using modified Bromage scale every 30 minutes until the end of block. Time to return of sensory block to 4 dermatomes below and time to return of Bromage scale to 0 were recorded. All vital measurements (oxygen saturation, heart rate, electrocardiogram, and non-invasive blood pressure) were performed at 0, 30, 60, 90, 120 and 180 minutes in all three groups of the study. Group DEX received dexmedetomidine additive and group F received fentanyl additive and group C (control) received normal saline.Results:Totally, 84 patients were randomly divided into three groups of 28 patients. Onset of sensory block in DEX group was significantly lower than those of fentanyl (P = 0.012) and control groups (P = 0.001). Duration of sensory block was significantly longer in DEX group compared to Fentanyl (P = 0.043) and control (P = 0.016) groups. Duration of motor block in the DEX group was significantly longer than those of the fentanyl (P = 0.014) and control groups. Heart rate and mean arterial pressure were significantly higher in the DEX group at 30, 60, 90,120, and 180 minutes compared to those of the other two groups (P < 0.05).Conclusions:Dexmedetomidine added to bupivacaine in spinal anesthesia is more effective to increase duration of block, providing more appropriate sedation and less postoperative pain scale and post-operative nausea and vomiting (PONV) compared to fentanyl additive.

A Comparison between Intrathecal Dexmedetomidine and Fentanyl as an Adjuvant to Hyperbaric Bupivacaine in Spinal Anaesthesia for Lower Limb Surgeries - A Double Blind Controlled Study

“…These findings clearly states that dexmedetomidine as an adjuvant provided prolonged sensory and motor duration compared to fentanyl as an adjuvant to hyperbaric bupivacaine. Similar findings was also observed by Khan et al [1] , Gupta R et al [20] The onset times observed conducted by AI Ghanem et al [10 dexmedetomidine than those observed attributed by difference in patient supine in our study).…”

“…Similar Gupta et al, Mehendru V et al [18] Heart rate (HR), mean arterial blood pressure (MAP) baseline, just after dural puncture, 15min, then at 5min intervals at 5min intervals at till Though there was theoretical possibility [22] , difference of HR was not statistically the above intervals. Similar results Khan et al, [1] Suresh et al, [23] and Statistically significant lowering Licensed Under Creative Commons Attribution CC BY [14] , Mehendru V et al [18] , Kishore et al [19] , ] , Safari et al [20] , Suresh et al [23] , Sunil BV et al [24] , Nayagam HA et al [25] and Routrey et al [26] The mechanism by which intrathecal α adrenoreceptor agonists prolong the motor and sensory block of local anaesthetics is at the best, speculative. It may be an additive or synergistic effect secondary to the different mechanisms of action of the local anaesthetics and intrathecal α adrenoreceptor agonists.…”

“…These finding was similar with Mahendru V et al [18] , who observed no difference in the onset time in patients receiving dexmedetomidine (10.3 ± 3.3 min) and fentanyl (9.6 ± 2.9) as adjuvant to hyperbaric bupivacaine and fentanyl (7.4 ± 3.3 min) as adjuvants to isobaric bupivacaine (P = 0.95). Similarly, no significant differences in sensory onset time among study groups were also by observed by Gupta R et al, [12] Kishore et al [19] and Safari et al [20] The onset times observed in the study conducted by AI Ghanem et al [10] were relatively shorter by dexmedetomidine than those observed by us which can be attributed by difference in patient positioning (lithotomy vs supine in our study).…”

“…Other side effects were comparable between these two groups. Comparable side effects were also observed by Khan et al, [1] Safari et al, [20] Gupta r et al, [21] and Suresh et al [23] …”

“…[29] We observed significantly delayed requirement of rescue analgesic with 5μg dexmedetomidine when compared with 25μg fentanyl, which supports the better analgesic efficacy of dexmedetomidine as an intrathecal adjunct. Similarly, significantly improved analgesic efficacy was seen by Kishore et al, [19] Safari et al, [20] Gupta et al, [21] Sunil BV et al [24] and AI Mustafa et al [30] Dose dependent prolongation of motor and sensory blockade with reduced analgesic requirement with increasing dosages of intrathecal dexmedetomidine was observed by Dhimar AA et al [31] The most significant side effects reported about the use of intrathecal α adrenoreceptor agonists are bradycardia and hypotension. [22] In the present study, these side effects were not significant probably because we used small dose of intrathecal dexmedetomidine with hyperbaric bupivacaine.…”