Comparison of intravenous with perineural dexamethasone for ultrasound-guided erector spinae plane block in patients...

Dexamethasone is used as an adjuvant to prolong the duration of peripheral nerve blocks. This study compares the effectiveness of intravenous (IV) versus perineural dexamethasone as an adjuvant to 0.5% ropivacaine for erector spinae plane block (ESPB) in patients undergoing modified radical mastectomy (MRM).

This prospective, double-blind, randomized study was conducted on 60 American Society of Anesthesiologists (ASA) physical status I/II adult females undergoing MRM under general anesthesia. Patients were divided into three groups: ropivacaine perineural dexamethasone (RPD), ropivacaine IV dexamethasone (RID), and ropivacaine normal saline (RNS). Time to rescue analgesia and morphine consumption over various time points (4, 8, 12, 24, and 48 h) were recorded postoperatively. Pain was assessed using the numeric rating scale (NRS).

The median time to first rescue analgesia was significantly higher in the RPD group (n = 20) 720 min [interquartile range (IQR: 465-1440), 95% confidence interval (CI): 638.78-1564.21)] in comparison to the RID group (n = 20) 435 min (IQR: 405-480, 95% CI: 284.8-811.1) and control (RNS) group (n = 20) 360 min (IQR: 240-415, 95% CI: 297.6-376.36) (P = 0.01). The median total morphine consumption in 24 h was least in the RPD group 2.0 mg (IQR: 1.0-3.0, 95% CI: 2-3) compared to the the RID 6.0 mg (IQR: 3.2-6.0, 95% CI: 6-8) and RNS groups 7.5 mg (IQR: 6.0-9.5, 95% CI: 6-8) (P = 0.01). The NRS scores both at rest and at physical activity were also lowest in the RPD group compared to other groups at various time points (4, 8,12, 24, and 48 h).

Perineural dexamethasone added as an adjuvant to 0.5% ropivacaine to ESPB prolongs the duration of analgesia, reduces morphine consumption, and reduces NRS scores at rest and physical activity as compared to IV dexamethasone in patients undergoing MRM.