Pain of Local Anesthetics: Rate of Administration and Buffering

doi:10.1016/S0196-0644(98)70278-1

Annals of Emergency Medicine

Volume 31, Issue 1, January 1998, Pages 36-40

https://doi.org/10.1016/S0196-0644(98)70278-1 Get rights and content

Abstract

Study objective: To determine the impact of administration rate and buffering on the pain associated with subcutaneous infiltration of lidocaine. Methods: Forty-two adult volunteers employed at a tertiary care center participated in this prospective, single-blinded study. Each subject received four lidocaine injections prepared and administered as follows: slow, buffered (SB); slow, unbuffered (SU); rapid, buffered (RB); rapid, unbuffered (RU). Buffering was accomplished by mixing 1% lidocaine with 8.4% sodium bicarbonate in a 9:1 ratio. Slow administration was 30 seconds and rapid was 5 seconds. Needle size (27-gauge), injection depth (.25 inch), lidocaine volume (1.0 mL), and temperature (room) were the same for each of the four injections. In all four conditions, the needle remained in the forearm for 30 seconds, to ensure blinding. The main outcome measure was the mean pain score for each condition, as recorded on a 10-cm visual analog scale. Results: The lowest pain scores (mean±SE) were recorded for the SU and SB conditions at 1.49±.29 and 1.48±.26, respectively, and they were significantly lower than the scores for RB (2.34±.28; P<.01) or RU (3.11±.33; P<.001). Each of the slow conditions was reported to be the “least painful” of the four significantly more often than either rapid condition. Conclusion: This is the largest blinded study to assess administration rate and the pain of a local anesthetic. We found that administration rate had a greater impact on the perceived pain of lidocaine infiltration than did buffering. [Scarfone RJ, Jasani M, Gracely EJ: Pain of local anesthetics: Rate of administration and buffering. Ann Emerg Med January 1998;31:36-40.]

Introduction

In the ED, it is frequently necessary to infiltrate intact skin with a local anesthetic before a field or digital block or before procedures such as a lumbar puncture, insertion of an arterial line, or an arthrocentesis are undertaken. However, the infiltration of the anesthetic itself is quite painful and causes patients, especially children, to become anxious and uncooperative with the ensuing procedure. There are many variables that influence the degree of pain experienced with local anesthetic infiltration. Previous studies have assessed specific agents,1, 2, 3 buffering,4, 5, 6, 7, 8 temperature,5, 9, 10, 11, 12, 13 depth of injection,¹⁰ area of the body anesthetized, needle size, and volume.

To date, there have been no studies adequately assessing the effect of administration rate on the degree of pain experienced or how the rate compares with buffering in its effect on pain. Therefore this study was conducted to compare the pain of infiltration associated with four different methods of lidocaine administration: slow and buffered (SB), slow and unbuffered (SU), rapid and buffered (RB), and rapid and unbuffered (RU). The study hypothesis was that slow administration and buffering would each result in less pain during infiltration.

Section snippets

Materials and Methods

Forty-two adult volunteers gave informed consent before participation, and the study was approved by the institutional review board of St Christopher's Hospital for Children. Excluded were those subjects known to be pregnant or to have an allergy to local anesthetic agents. To minimize subject bias and ensure blinding, each participant was told that he or she would receive four different types of anesthetic solutions, rather than two different solutions at two different rates.

Study drugs were

Results

Forty-four adult volunteers were initially enrolled, 26 women and 18 men. Subsequently, one man was excluded because the needle and syringe disconnected during an infiltration, and one woman was excluded because a syringe was mislabeled. Therefore 42 subjects were evaluated. Significance testing showed that the sequence in which the four conditions were administered to each subject was in a random pattern (Table 1). Similarly, the sequence in which forearm sites were used was random with the

Discussion

This is the first study to adequately assess the effect of administration rate on the degree of pain experienced with local lidocaine and how that rate compares with buffering in its effect on the pain of administration. We found that rate of infiltration was strongly predictive and that buffering was modestly predictive of perceived pain for subcutaneous injections of lidocaine through intact skin. Each slow condition yielded lower pain ratings than either rapid condition. Also, unbuffered

References (17)

R Morris et al.
Comparison of pain associated with intradermal and subcutaneous infiltration with various local anesthetic solutions
Anesth Analg
(1987)
RW Morris et al.
A controlled trial of pain on skin infiltration with local anesthetics
Anesth Intensive Care
(1984)
GA Smith et al.
Comparison of topical anesthetics without cocaine to tetracaine-adrenaline-cocaine and lidocaine infiltration during repair of lacerations: Bupivacaine-norepinephrine is an effective new topical anesthetic agent
Pediatrics
(1996)
RA Christoph et al.
Pain reduction in local anesthetic administration through pH buffering
Ann Emerg Med
(1988)
TJ Mader et al.
Reducing the pain of local anesthetic infiltration: Warming and buffering have a synergistic effect
Ann Emerg Med
(1994)
JM Bartfield et al.
Buffered versus plain lidocaine as a local anesthetic for simple laceration repair
Ann Emerg Med
(1990)
W McKay et al.
Sodium bicarbonate attenuates pain on skin infiltration with lidocaine, with or without epinephrine
Anesth Analg
(1987)
DA Redd et al.
Towards less painful local anesthesia
Ala Med
(1990)

There are more references available in the full text version of this article.

Cited by (145)

Skin Biopsy Techniques
2022, Primary Care - Clinics in Office Practice
Regional Anesthesia
2019, A Practice of Anesthesia for Infants and Children
Regional anesthesia has become an integral and common component of both intraoperative anesthesia and postoperative analgesia in infants and children. Advantages of regional blockade include the reduction of general anesthetic dose requirements, effective blunting of hemodynamic and autonomic responses, and excellent postoperative analgesia with decreased requirement of systemic analgesics and their concomitant side effects. For many orthopedic operations, increasing use of peripheral nerve blockade permits the anesthesiologist to provide long durations of analgesia limited to the surgical site. Spinal anesthesia in infants has been demonstrated to be an effective alternative to general anesthesia for subumbilical operations lasting an hour or less. However, the risks of local anesthetic toxicity may be magnified in infants and children because of their size and immaturity, and great care and precision must be used when choosing volume and concentration. Because the vast majority of regional blocks in children are performed with patients under general anesthesia, early signs of toxicity are usually obscured. The emergence of lipid emulsion therapy for local anesthetic systemic toxicity has dramatically altered our approach and the successful outcome to these events and should be administered promptly. Large-scale prospective data from multicenter collaborative studies have documented that regional anesthetics in children have a high degree of safety, and prospective data have confirmed that administering blocks to children under general anesthesia confers no increased risk of injury. While one must have specific technical skills, as well as an understanding of the differences in pediatric physiology, anatomy, and pharmacology, to use regional blockade in infants and children, the benefits of these techniques are great.
Comparison of Two Lidocaine Administration Techniques on Perceived Pain From Bedside Procedures: A Randomized Clinical Trial
2018, Chest
Lidocaine is used to alleviate procedural pain but paradoxically increases pain during injection. Pain perception can be modulated by non-noxious stimuli such as temperature or touch according to the gate control theory of pain. We postulated that lidocaine dripped onto the skin prior to injection would cool or add the sensation of touch at the skin surface to reduce pain perception from the procedure.
A randomized clinical trial of patients referred to the procedure service from February 2011 through March 2015 was conducted. All patients received 1% subcutaneous lidocaine injection. Patients randomized to the intervention group had approximately 1 to 2 ml of lidocaine squirted onto the skin surface prior to subcutaneous lidocaine injection. Patients were blinded to the details of the intervention and were surveyed by a blinded investigator to document the primary outcome (severity of pain from the procedure) using a visual analog scale.
A total of 481 patients provided consent and were randomized to treatment. There was a significant improvement in the primary outcome of procedural pain (control, 16.6 ± 24.8 mm vs 12.2 ± 19.4 mm; P = .03) with the intervention group as assessed by using the visual analog scale score. Pain scores were primarily improved for peripherally inserted central catheters (control, 18.8 ± 25.6 mm vs 12.2 ± 18.2 mm; P = .02) upon subgroup analysis.
Bedside procedures are exceedingly common. Data regarding the severity of procedural pain and strategies to mitigate it are important for the informed consent process and patient satisfaction. Overall, pain reported from common bedside procedures is low, but pain can be further reduced with the addition of lidocaine onto the skin surface to modulate pain perception.
ClinicalTrials.gov; No.: NCT01330134; URL: www.clinicaltrials.gov.
Dripped Lidocaine: A Novel Approach to Needleless Anesthesia for Mucosal Lacerations
2018, Journal of Emergency Medicine
Oral lacerations represent a unique challenge for anesthesia in the emergency department. Many options exist for local anesthesia, but these options are often associated with pain from injections or anxiety from anticipated needle injection.
We introduce a novel and needleless approach to achieving local anesthesia for oral mucosa repair by dripping injectable lidocaine directly onto mucosal wounds prior to repair. This method is well tolerated and achieves appropriate anesthesia without undesirable side effects.
Dripped injectable lidocaine may be an alternative method for mucosal anesthesia in the pediatric population.
Minimizing the Pain of Local Anesthetic Injection
2024, Applied Radiology
Buffered Versus Nonbuffered Local Anesthetics and Local Pain Scores in Upper Eyelid Blepharoplasty: Randomized Controlled Trial
2023, Ophthalmic Plastic and Reconstructive Surgery

View all citing articles on Scopus

^☆: From the Department of Pediatrics, Temple University School of Medicine^*; Section of Pediatric Emergency Medicine, St Christopher's Hospital for Children^‡; and Department of Community and Preventive Medicine, Allegheny University of the Health Sciences, MCP Hahnemann School of Medicine,^§ Philadelphia, PA.

^☆☆: Reprint no. 47/1/87279

^★: Address for reprints: Richard J Scarfone, MD, Pediatric Emergency Medicine, St Christopher's Hospital for Children, Erie Avenue at Front Street, Philadelphia, PA 19134, 215-427-5366, Fax 215-427-4668, E-mail [email protected]

View full text

Pain of Local Anesthetics: Rate of Administration and Buffering☆,☆☆,★

Abstract

Introduction

Section snippets

Materials and Methods

Results

Discussion

Comparison of pain associated with intradermal and subcutaneous infiltration with various local anesthetic solutions

Anesth Analg

A controlled trial of pain on skin infiltration with local anesthetics

Anesth Intensive Care

Comparison of topical anesthetics without cocaine to tetracaine-adrenaline-cocaine and lidocaine infiltration during repair of lacerations: Bupivacaine-norepinephrine is an effective new topical anesthetic agent

Pediatrics

Pain reduction in local anesthetic administration through pH buffering

Ann Emerg Med

Reducing the pain of local anesthetic infiltration: Warming and buffering have a synergistic effect

Ann Emerg Med

Buffered versus plain lidocaine as a local anesthetic for simple laceration repair

Ann Emerg Med

Sodium bicarbonate attenuates pain on skin infiltration with lidocaine, with or without epinephrine

Anesth Analg

Towards less painful local anesthesia

Ala Med