RESUMEN
STUDY OBJECTIVE: To compare efficacy and cost of lidocaine cutaneous anesthesia by two jet injectors to routine needle infiltration for pain relief of intravenous (i.v.) catheterization, hypothesizing that jet injection of lidocaine is less painful than its needle infiltration. DESIGN: Randomized, prospective, controlled trial. SETTING: University hospital outpatient surgical unit. PARTICIPANTS: 75 surgical patients ASA I and II. INTERVENTIONS: Three groups of 25 patients each were given intradermal lidocaine anesthesia via conventional 25-gauge needle/syringe; by MedEJet or Biojector jet injector prior to IV catheterization with an 18-gauge Jelco catheter. MEASUREMENTS AND MAIN RESULTS: Visual analogue pain scores (VAS) (0 = no pain, 10 = intolerable pain) and subjective pain intensity scores (PIS) (0 = not painful, 4 = intolerable pain) at lidocaine application and at i.v. catheterization, were recorded. Cost assessment of each method was made. At local anesthetic application, no pain by proportion of VAS = 0 with MedEJet: 25/25 (confidence interval [CI]: 0.868, 0.999) and Biojector: 24/25 (CI 0.804, 0.991) was noted, but-22 of 25 patients experienced pain with needle administration: (with VAS = 0; 3/25 [CI: 0.044, 0.302]) (posterior probability [PP] > 0.999). The corresponding VAS scores (means +/- SD) were 0.00 +/- 0.00, 0.04 +/- 0.20, and 2.4 +/- 2.23 (p < 0.001). No pain by proportion of PIS = 0 with MedEJet: 25/25 (CI: 0.868, 0.999 and Biojector: 23/25 (0.749, 0.976) was noted, but pain in 20/25 was felt with the needle: 5/25 (CI: 0.090, 0.394) (PP > 0.999). The corresponding PIS scores were 0.00 +/- 0.00, 0.16 +/- 0.55, and 1.24 +/- 1.00 (p < 0.001). At i.v. catheterization, no pain by proportion of VAS = 0 with MedEJet: 22/25 (CI: 0.698, 0.956) or Biojector: 21/25 (CI: 0.651, 0.934) was noted; but pain in 19/25 with needle administration was experienced: 6/25 (CI: 0.116, 0.436) (PP > 0.999). The corresponding scores were 0.12 +/- 0.33, 0.44 +/- 0.20, and 1.64 +/- 1.50 (p < 0.001). No pain by proportion of PIS = 0 with MedEJet: 24/25 (CI: 0.804, 0.991) or Biojector: 24/25 (CI: 0.804, 0.991) was noted, but pain was apparent in 12/25 with needle administration: 13/25 (CI: 0.334, 0.701) (PP > 0.999). The corresponding scores were 0.00 +/- 0.00, 0.00 +/- 0.00, and 0.76 +/- 0.88 (p < 0.001). Cost per application: MedEJet = $0.13; needle/syringe = $0.50; Biojector = $0.94. CONCLUSIONS: Almost completely painless i.v. catheterization was carried out by jet injection of lidocaine, but needle infiltration produced discomfort or pain and did not significantly reduce discomfort or pain at the i.v. needle insertion.
