Study objective: This study compared efficacy, degree of discomfort, and time to anesthesia of digital blocks and metacarpal blocks for digital anesthesia.
Design: Randomized, prospective, nonblinded, clinical study conducted from April 1992 to January 1993. Patients served as their own controls.
Setting: Inner-city and community hospital emergency departments.
Type of participants: Convenience sample of 30 adult patients, with third or fourth finger injuries including and distal to the proximal interphalangeal joint that required digital anesthesia.
Interventions: Digital blocks and a metacarpal blocks were performed (one per side) on all 30 patients (total of 60 blocks). The order of the blocks was randomized.
Measurements: A digital block and a metacarpal block were performed on each patient. Patients immediately rated the pain associated with each technique on a nonsegmented visual analog scale. Efficacy was assessed by requirement for additional anesthesia and anesthesia to pinprick. Time to anesthesia was assessed after each block in 23 patients.
Results: Mean visual analog scale pain scores were 2.53 for digital block and 3.38 for metacarpal block (P = .1751, Student's t-test). Metacarpal block failed anesthesia to pinprick in 23% of patients compared to 3% for digital block (P = .0227, chi 2). Time to anesthesia was significantly shorter for digital block compared to metacarpal block, with a mean of 2.82 minutes versus 6.35 minutes (P < .0001, Student's t-test).
Conclusion: Digital block and metacarpal block, as described in this study, are equally painful procedures. Digital block, however, is more efficacious and requires significantly less time to anesthesia for the injured finger.