Date: June 15th, 2018

Reference: Silva et al. Safety and Efficacy of Intravenous Lidocaine for Pain Management in the Emergency Department: A Systematic Review. Ann Emerg Med. 2018

Guest Skeptics: Dr. Sergey Motov is an Emergency Physician in the Department of Emergency Medicine, Maimonides Medical Center in New York City.

Lucas Silva is a 5th year medical student from Brazil (6-years program in Latin America) and a former Research Fellow in the Department of Emergency Medicine at the Mayo Clinic (Rochester, Minnesota).

Lucas Silva

Case: A 42-year-old man presents to the emergency department (ED) with chief complaint of severe right flank pain that radiates to his groin of three hours duration. The patient also reports nausea, increase in frequency of urination and blood in his urine. He is writhing in pain and on physical examination he was noted to have a severe right flank tenderness to palpation and tenderness at right costo-vertebral angle. You entertain the clinical diagnosis of renal colic and proceed with ordering 10mg intravenous ketorolac. On re-assessment at 20 minutes post-analgesia, the patient is still complaining of a moderate degree of pain and states that morphine worked well in the past, but he is wondering if you can take away his pain without an opioid. While contemplating your next analgesic choice you suddenly remember listening to a podcast that discussed the role of intravenous lidocaine in managing pain of renal colic origin (SGEM#202). You reassured the patient that you will check on the feasibility of other non-opioid analgesics, but at the same time you decided to quickly review available data on IV Lidocaine utility for acute pain in the ED.

Dr. Sergey Motov

BackgroundPain is one of the most common, if not the most common reason patients present to the ED. Physicians have many pharmacological and non-pharmacological ways to provide safe and effective pain control.

Anesthetic agents like lidocaine that target sodium channels are widely used in the ED for topical and local anesthesia. Lidocaine is a local anesthetic agent with analgesic, anti-hyperalgesic, and anti-inflammatory properties. It has a short half-life (60 to 120 minutes) with often predictable adverse effects.

It has been suggested that IV lidocaine could be an alternative for pain control instead of opioids or NSAIDs. This would be when these other treatment modalities have been ineffective or associated with adverse effects.

We have looked at IV lidocaine for the treatment of renal colic on SGEM #202. The SGEM bottom line from that episode was that lidocaine cannot be recommended for the treatment of renal colic.

Clinical QuestionIs administration of intravenous lidocaine safe and effective in managing patients presenting to the emergency department with acute or chronic pain?

Reference: Silva et al. Safety and Efficacy of Intravenous Lidocaine for Pain Management in the Emergency Department: A Systematic Review. Ann Emerg Med. 2018

  • Population: Studies of adult patients (>17 years of age) who received at least one dose of IV lidocaine in the ED for their management of acute or chronic pain.
    • Exclusions: Studies in which patients received IV lidocaine in a setting outside the ED or for indications other than analgesia. Studies that used lidocaine for regional anesthesia (ex: Bier Block) were also not included.
  • Intervention: IV lidocaine given in the ED.
  • Comparison: Active controls (opioids, NSAIDs) or placebo.
  • Outcomes:
    • Efficacy Outcomes: Reduction in pain score (through visual analog scale or any other pain assessment tool) and need for rescue analgesia.
    • Safety OutcomesIncidence of adverse drug reactions, both overall and separated into non-serious (e.g. dizziness) and serious (e.g. cardiac arrest) categories.
    • Risk of Bias: We used the Cochrane Collaboration Bias Appraisal Tool for the randomized controlled trials and a modified Newcastle-Ottawa Scale tool for observational studies.
    • Certainty: The certainty for each outcome was evaluated with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methods.
  • Study Design: Original research articles, including randomized controlled trials and observational studies were considered. Case reports were excluded.

Authors’ Conclusions: “There is limited current evidence to define the role of intravenous lidocaine as an analgesic for patients with acute renal colic and critical limb ischemia pain in the ED. Its efficacy for other indications has not been adequately tested. The safety of lidocaine for ED pain management has not been adequately examined.”

Quality Checklist for Therapeutic Systematic Reviews:

  1. The clinical question is sensible and answerable.  Unsure
  2. The search for studies was detailed and exhaustive. Yes
  3. The primary studies were of high methodological quality. No
  4. The assessment of studies were reproducible. Yes
  5. The outcomes were clinically relevant. Yes
  6. There was low statistical heterogeneity for the primary outcomes. Not applicable
  7. The treatment effect was large enough and precise enough to be clinically significant. Not applicable

Key Results: Almost 2,000 titles were screened for inclusion with 61 articles getting a full text review. Eight studies met inclusion/exclusion criteria, six randomized controlled trials (RCTs) and two case-series for a total of 536 patients. The causes of pain included critical limb ischemia, migraine headaches, radicular low back pain and renal colic.

  • Efficacy: For the efficacy outcomes, there were six RCTs included and two case-series. Among the six RCTs, IV lidocaine had efficacy equivalent to that of active controls in two studies and was better than active controls in two other studies. In particular, IV lidocaine had pain score reduction comparable to or higher than that of intravenous morphine for pain associated with renal colic and critical limb ischemia. Lidocaine did not appear to be effective for migraine headache in two studies.
  • Safety: There were 20 adverse events reported by six studies among 225 patients who received intravenous lidocaine in the ED, 19 non-serious and one serious (rate 8.9%, 95% confidence interval 5.5% to 13.4% for any adverse event; and 0.4%, 95% confidence interval 0% to 2.5% for serious adverse events).
  • Risk of Bias

  • Certainty in the Evidence:

Listen to the podcast on iTunes to hear Sergey’s and Lucas’ responses to my five nerdy questions.

1) Search Strategy: This was an excellent example of how to do a good search. Can you please explain how you did the search so others interested in doing a systematic review can follow your example?

2) Combining Studies: Why did you include the two case-series which are observational studies in the systematic reviews? These are a lower form of evidence and can only conclude associations.

3) Quality of Evidence: The quality of evidence was low due to methodological problems, risk of bias, inconsistency, small studies and imprecision. There was so much heterogeneity (different painful conditions, lidocaine doses, outcome measures) that you were not able to do a meta-analysis. What value to you think a systematic review (without meta-analysis) has for clinicians?

4) Hierarchy of EvidenceThere is a pyramid of evidence for evidence-based medicine. On the bottom is background information/expert opinion and at the top is the systematic review. However, in this case when the quality of evidence is so poor I would suggest a well done RCT gets us closer to the truth than a number of low quality RCTs and observational studies.

5) Where Do We Go: You guys are both pain researchers. Where to do we go from here? What studies would you suggest to address the insufficient evidence we have to answer the question of whether or not IV lidocaine is safe and effective for pain control in the ED?

Comment on Authors’ Conclusion Compared to SGEM Conclusion: I agree with the authors’ conclusion that this systematic review of limited, highly heterogenous, low quality evidence does not support a routine administration of intravenous lidocaine to manage pain of renal colic origin or critical limb ischemia in the emergency department.

SGEM Bottom Line: The currently available evidence is not strong enough to support the routine use of IV lidocaine for analgesia in the emergency department.

Case ResolutionYou proceed with ordering IV morphine with nearly complete resolution of pain while in the ED and subsequent discharge home with urological follow-up.

Clinical Application: The clinical utility of IV lidocaine for managing acute pain in the ED is yet to be determined by conducting more robust research with broader inclusion criteria (elderly and those with pre-existing cardiac disease) and pain syndromes. However, on case-by-case basis in situations when opioids and NSAIDs are contraindicated and/or intolerable, intravenous lidocaine might be considered for pain control.

What Do I Tell My Patient? One of the non-opioid analgesic that I considered ordering for you does not have good evidential support for its pain relief and safety in the ED. Therefore, I am going to proceed with IV morphine.

Keener Kontest: Last weeks’ winner was David Lemonick again. He knew a systolic blood pressure less than 100 mmHg was a reason to stop the procainamide infusion as part of the Ottawa Aggressive Protocol for atrial fibrillation.

Listen to the SGEM podcast on iTunes to hear this weeks’ question. If you know the answer send an email to TheSGEM@gmail.com with “keener” in the subject line. The first correct answer will receive a cool skeptical prize.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’Guide to Emergency Medicine.