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October 17-21, 2009 New Orleans, LA Home Abstract Archive Search Abstracts 2009 Session Grid 2009 Meeting Website Policy Statements ASA Website Feedback 
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A897
October 16, 2006 9:00 AM - 11:00 AM Room Hall E, Area E |
| Don't Be AmBEVELent about Needle Position |
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Yiliam Rodriguez, M.D., Pushpa Koyyalamudi, M.D., Luciana Curia, M.D., Ernesto Grenier, M.D., Keith Candiotti, M.D. Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami, Miami, Florida |
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BACKGROUND Local anesthetic infiltration with lidocaine is a commonly used technique to decrease the pain associated with many procedures such as intravenous cannulation (1). However, injection of local anesthetic itself can often be uncomfortable for patients. Though there appears to be no scientific validation, some practitioners advocate placing the needle bevel down to reduce the pain associated with local anesthetic injections. We conducted a prospective, randomized trial to compare the effect of two different bevel positions (bevel up versus bevel down) and the pain associated with the subcutaneous injection of lidocaine. METHODS Following approval by IRB consent was obtained from 50 adult volunteers. The study procedure was performed by one study coordinator for consistency. The area to be injected was cleaned with 70% isopropyl alcohol and allowed to dry for 1 min. Subjects were injected at the mid-point of the mid-portion of each forearm with 0.5 ml of 1% lidocaine using a 1ml tuberculin syringe with a 29G needle over 2 to 3 seconds. All subjects received local anesthetic infiltration in both forearms beginning with the right arm. Subjects were randomized to one of the two groups, needle bevel up for the first injection or needle bevel down. The participants used the verbal rating score (VRS) to quantify the sensation of pain on a scale of 0-10 (0= no pain versus10= worst pain). STATISTICAL ANALYSIS To achieve a power of 0.80 and a significant p value of < 0.05, a sample size of 25 per group was determined to detect a difference of 1-2 points on the 0-10 VRS pain score. A repeated measures analysis of variance was used for all analyses. The primary analysis compared needle orientation. Statistical tests resulting in a p-value of 0.05 or less were considered to be statistically significant. RESULTS Subjects reported significantly higher pain scores when the needle was placed bevel down as compared to placing it bevel up (3.44±0.29 down vs. 2.66±0.22 up; P = 0.02). Paired T-test results revealed no significant difference between the groups for age or gender. DISCUSSION Although there is no evidence in the literature demonstrating the effect of needle orientation on the perceived pain of subcutaneous injections some practitioners advocate a particular needle orientations with the intent of reducing the pain of injection. Our study was designed to address this question. Similar pain scores were observed in subjects regardless of age or gender. Ethnicity was not found to be a significant variable when considered alone. However in Hispanics, orienting the bevel down during local anesthetic injection resulted in higher pain scores reaching statistical significance (4.06±0.4 down vs. 2.24±0.29 up, P < 0.01). The significance of this incidental finding is unclear but it has been noted previously that ethnicity and pain scores may correlate. According to a recent survey of anesthesiologists the pain of IV insertion is among the top five low morbidity clinical anesthesia outcomes that are common and important to avoid in order to improve the quality of clinical care (2). Our study demonstrates that placing the needle bevel down significantly increases the perceived pain of a subcutaneous lidocaine injection. REFERENCES 1) Harris T et al. Emerg Med J 2001; 18: 175-7 2) Macario A et al. Anesth Analg 1999;88: 1085-91. Anesthesiology 2006; 105: A897 |