Pain during arterial puncture

Study objective: To quantify the level of pain reported by patients during arterial puncture with or without local anesthesia, and to compare the results with levels reported for venous puncture. Design: Double-blind study of puncture with and without local anesthesia. Setting: Pulmonary function laboratory, department of pneumology. Patients: We studied 270 consecutive patients undergoing arterial puncture divided into two groups. In group A (n=210), we assessed level of pain with and without local anesthesia and with placebo. In group B (n=60), we compared pain of arterial and venous puncture. Interventions: The arterial puncture was performed in the radial artery; venous puncture was in the median basilic vein. Measurements and results: The pain was quantified on a visual analog scale (10 cm). Mean level of pain for all arterial punctures without anesthesia or placebo was slight to moderate (3.01±1.94 cm). Subcutaneous anesthetic infiltration before arterial puncture significantly reduced pain by more than 50%, to 1.50±1.54 cm, a level that was significantly lower than the pain level reported after conventional venous puncture (1.80±1.10 cm). The pain reported by patients who received no anesthesia was not significantly different (p=0.45) from that perceived by those who received subcutaneous infiltration of saline solution (placebo). Conclusions: Arterial puncture with prior infiltration of local anesthetic is the least painful procedure among those studied. Use of local anesthesia is indicated whenever conventional arterial puncture is required.