Effect of Intravenous Dexamethasone on the Duration of Analgesia Provided by Supraclavicular Brachial Plexus Block for Upper Limb Surgery

Pain is associated with increased sympathetic activity leads to tachycardia, elevated blood pressure and myocardial insults so pain control is necessary during the surgery and in the postoperative period. Aim of the study was to study the effect of intravenous dexamethasone on the duration of analgesia provided by supraclavicular block (SCB) for upper limb surgery.

75 patients, age between 18 to 70 years of either sex, ASA class I and II, who were undergoing upper limb surgery randomized into three groups of 25 patients each by computer generated random number. Group S - 25 patients were given 5ml of normal saline intravenously along with ultrasound-guided SCB with 25ml 0.5% bupivacaine. Group DF - 25 patients were given 4mg intravenous dexamethasone in 5ml normal saline along with ultrasound-guided SCB with 25ml 0.5% bupivacaine. Group DE - 25 patients were given 8mg intravenous dexamethasone in 5ml normal saline along with ultrasound-guided SCB with 25ml 0.5% bupivacaine.

The demographic data were comparable in all groups. The VAS score was significantly lower in Group DF and DE compared to Group S at 3,4,6,8,10,12 and 24 hours, with p values < 0.0001 at 3,4,5,6,8,10 and 12 hours and p value 0.0002 at 24 hours. The VAS scores between the groups DF and DE were comparable at 3,4,5,6,8,10,12 and 24 hours without any significant difference. The time for first rescue analgesia was significantly in Group DF and DE compared to Group S (p value <0.0001). There was no significant difference between the groups DF and DE in the time for first rescue analgesia (p value 0.75).

We conclude that dexamethasone used intravenously even in lower doses as 4mg along with supraclavicular brachial plexus block effectively increases the duration of analgesia and motor blockade, shortens the onset of sensory and motor blockade, reduces the total analgesic requirement in the first 24 hours after surgery.