Intravenous Lidocaine Versus Morphine for Severe Pain in the ED

Objective: The purpose of this pilot study is to determine the analgesic efficacy of intravenous lidocaine versus morphine for the treatment of severe pain in the emergency department (ED).

Study design: Open-label, randomized, controlled pilot trial. Participants: Investigators and research assistants will recruit patients ≥18 years old with severe pain (NRS ≥7) and an anticipated stay in the emergency department ≥1 hour. A sample size calculation was performed and 32 patients will be enrolled.

Intervention: After a trained research assistant obtains written informed consent, eligible participants will be randomized to the intravenous lidocaine or morphine arms of the study. In the intravenous lidocaine arm, patients will receive IV lidocaine (75 mg if <50kg, 100 mg if 50 - 100 kg, and 150 mg if >100 kg) over 10 minutes in a 100 mL normal saline minibag followed by a 50 minute IV lidocaine drip (75 mg if <50kg, 100 mg if 50 - 100 kg, and 150 mg if >100 kg). In the morphine arm, the ED provider will choose an appropriate dose of morphine for the patient. At 20 and 40 minutes, the participants will be asked "Would you like additional pain medication?". Participants responding in the affirmative will receive morphine 4 mg IV.

Data collection: The trained research assistant will collect data on the patients' pain scores, side effects, and rescue morphine.

Statistical analysis: Investigators will perform descriptive statistics and compare pain scores and pain relief at each time point with unpaired t-tests.

• Intravenous lidocaine (Drug), also known as lignocaine, Xylocaine: Intravenous lidocaine drip over 10 minutes followed by intravenous lidocaine drip over 50 minutes
• Intravenous morphine (Drug), also known as duramorph: Emergency department provider chooses appropriate dose of intravenous morphine

Primary outcomes

• Pain Score (NRS 0-10) [At 60 minutes]: Pain score is rated on the Numeric Rating Scale from 0-10. 0 represents no pain and 10 represents the worst possible pain.

Secondary outcomes

• Pain Score (NRS 0-10) [At 10 minutes]: Pain score recorded on the numeric rating scale 0-10.
• Pain Score (NRS 0-10) [At 20 minutes]: Pain score recorded on the numeric rating scale 0-10. 0 represents no pain and 10 represents the worst pain.
• Pain Score (NRS 0-10) [At 30 minutes]: Pain score recorded on the numeric rating scale 0-10.
• Pain Score (NRS 0-10) [At 40 minutes]: Pain score recorded on the numeric rating scale 0-10.
• Pain Score (NRS 0-10) [At 50 minutes]: Pain score recorded on the numeric rating scale 0-10.
• Pain Relief at 10 Minutes Compared to Baseline. [At 10 minutes]: Pain NRS at 0 minutes minus pain NRS at 10 minutes
• Pain Relief at 20 Minutes Compared to Baseline. [at 20 minutes]: Pain numeric rating scale (NRS) at 0 minutes minus pain NRS at 20 minutes. NRS is a scale ranging from 0, no pain, to 10 worst pain.
• Pain Relief at 30 Minutes Compared to Baseline. [at 30 minutes]: Pain numeric rating scale (NRS) at 0 minutes minus pain NRS at 30 minutes NRS is a scale ranging from 0, no pain, to 10 worst pain.
• Pain Relief at 40 Minutes Compared to Baseline. [At 40 minutes]: Pain numeric rating scale (NRS) at 0 minutes minus pain NRS at 40 minutes. NRS is a scale ranging from 0, no pain, to 10 worst pain.
• Pain Relief at 50 Minutes Compared to Baseline. [At 50 minutes]: Pain numeric rating scale (NRS) at 0 minutes minus pain NRS at 50 minutes. NRS is a scale ranging from 0, no pain, to 10 worst pain.
• Pain Relief at 60 Minutes Compared to Baseline. [At 60 minutes]: Pain numeric rating scale (NRS) at 0 minutes minus pain NRS at 60 minutes. NRS is a scale ranging from 0, no pain, to 10 worst pain.
• Number of Participants Requiring Rescue Medications [At 20 and 40 minutes]: The percentage of patients requiring rescue IV morphine at 20 and 40 minutes
• Patient Satisfaction [60 minutes]: The proportion of patients saying, "Yes" to "Would you have this pain medication again for similar pain?"
• Number of Participants Reporting Adverse Events [0-60 minutes]: Participants will be observed for the following adverse events and side effects: seizure, bradyarrhythmias, hyper or hypotension, perioral numbness, tinnitus, metallic taste, other, hypotension, hypoxia, nausea, vomiting, itching, or other side effects. Participants have the opportunity to report other side effects during the study

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Subject has severe pain (NRS ≥7)
* Subject has anticipated ED stay of ≥1 hour

Exclusion Criteria:

* High acuity trauma patients
* Patients deemed to critically ill by ED provider
* Active psychosis
* Pregnancy
* History of heart block or bradycardia
* Allergy to lidocaine or amide type local anesthetic
* History of seizures

Participant flow

Outcome results

• Pain Score (NRS 0-10) (Primary), Mean, units on a scale: Intravenous Lidocaine 5.1 (3.3 to 6.8); Morphine 4.2 (3.0 to 5.4)
• Pain Score (NRS 0-10) (Secondary), Mean, units on a scale: Intravenous Lidocaine 8.1 (7.1 to 9.0); Morphine 8.9 (8.3 to 9.6)
• Pain Score (NRS 0-10) (Secondary), Mean, units on a scale: Intravenous Lidocaine 7.4 (6.3 to 8.4); Morphine 6.2 (4.6 to 7.8)
• Pain Score (NRS 0-10) (Secondary), Mean, units on a scale: Intravenous Lidocaine 7.0 (5.9 to 8.1); Morphine 5.6 (4.0 to 7.1)
• Pain Score (NRS 0-10) (Secondary), Mean, units on a scale: Intravenous Lidocaine 6.3 (5.0 to 7.5); Morphine 4.7 (3.2 to 6.3)
• Pain Score (NRS 0-10) (Secondary), Mean, units on a scale: Intravenous Lidocaine 5.6 (4.1 to 7.1); Morphine 4.6 (3.1 to 6.0)
• Pain Relief at 10 Minutes Compared to Baseline. (Secondary), Mean, units on a scale: Intravenous Lidocaine 1.1 (0.5 to 1.8); Morphine 2.0 (0.9 to 3.0)
• Pain Relief at 20 Minutes Compared to Baseline. (Secondary), Mean, units on a scale: Intravenous Lidocaine 1.8 (1.1 to 2.5); Morphine 2.8 (1.4 to 4.1)
• Pain Relief at 30 Minutes Compared to Baseline. (Secondary), Mean, units on a scale: Intravenous Lidocaine 2.2 (1.4 to 3.0); Morphine 3.4 (1.9 to 4.7)
• Pain Relief at 40 Minutes Compared to Baseline. (Secondary), Mean, units on a scale: Intravenous Lidocaine 2.9 (1.7 to 4.1); Morphine 4.2 (2.9 to 5.6)
• Pain Relief at 50 Minutes Compared to Baseline. (Secondary), Mean, units on a scale: Intravenous Lidocaine 3.6 (2.2 to 5.0); Morphine 4.4 (3.2 to 5.6)
• Pain Relief at 60 Minutes Compared to Baseline. (Secondary), Mean, units on a scale: Intravenous Lidocaine 4.1 (2.6 to 5.7); Morphine 4.8 (3.7 to 5.8)
• Number of Participants Requiring Rescue Medications (Secondary), Count of participants, Participants: Intravenous Lidocaine 5; Morphine 4
• Patient Satisfaction (Secondary), Count of participants, Participants: Intravenous Lidocaine 13; Morphine 14
• Number of Participants Reporting Adverse Events (Secondary), Count of participants, Participants: Intravenous Lidocaine 2; Morphine 6

Adverse events

Other adverse events by term

Limitations and caveats: This study was limited by a small sample size and lack of blinding.

• Andrew Herring, MD, Principal investigator, Alameda Health System, Highland Hospital