For a study, researchers sought to evaluate the analgesic effect of sub-dissociative dosage ketamine (SDK) and ultrasound-guided selective peripheral nerve block (PNB) for the treatment of acute pain in patients with extremities injuries who visit the emergency department (ED).

In the ED of a tertiary care facility, a prospective, open-label, randomized clinical study was carried out. Either SDK or ultrasound-guided selective PNB was given to the patients. The main result was a minimum 3-point decrease in pain on the numerical rating scale (NRS) without rescue analgesia. On each arm, the secondary outcomes included the requirement for rescue analgesics, adverse events, and patient satisfaction.

The final study comprised 111 individuals with isolated traumatic extremities injuries. At 30, 60, 120, 180-, and 240- minutes after the intervention, the NRS score was substantially lower in the PNB group compared to the SDK group [group ~ time interaction, F (5, 647) = 21.53, P≤ 0.001]. At 30 minutes after the intervention, every patient in the PNB group had the primary result (NRS ≥3 decreases), as opposed to 36 (65%) in the SDK group [-1.02(-1.422,0.622)]. In the SDK group, 10 patients (18%) required rescue analgesia, while none did so in the PNB group [0.663(0.277,1.050)]. Compared to the SDK group, the NRS score at 30 minutes had dramatically lessened in the PNB groups [-2.166(-2.640, -1.692)]. In the SDK group, dizziness was the most frequently reported adverse event (35/64%), followed by nausea (15/27%). The PNB group’s patients didn’t mention any difficulties at all. The PNB group had more satisfied patients than the SDK group did.

The study provided proof that ultrasound-guided PNB was more effective than SDK in managing acute pain brought on by limb injuries and was also linked to improved patient satisfaction. In the PNB group, rescue analgesia was substantially less necessary. SDK was linked to a significant prevalence of nausea and vertigo.