Ketamine as a Supplement to Local Anesthesia for Minor Procedures

Patient experiences in the emergency department (ED) are commonly painful and uncomfortable, particularly when patients must undergo procedures. Managing acute pain and procedural pain for minor procedures in the ED can be challenging. Ketamine is an N-methyl-D aspartate receptor agonist gaining popularity in clinical settings and has also been shown in several studies to potentially treat depression. Several randomized clinical studies have shown that ketamine is a comparable pain relief medication to opioid analgesics in both acute pain and traumatic settings. Its uses for pain control in the ED have been extensively studied with evidence supporting its safety and efficacy. Ketamine can be administered in different ways including intravenously and intranasally. Intravenously, doses above 1 mg/kg of ketamine can induce dissociation- this dose is commonly used for procedural sedation. At lower doses, specifically sub-dissociative doses, ketamine (SDK) acts to alleviate pain (cancerous, neuropathic, and perioperative). Trials using intravenous SDK suggest efficacy similar to traditional intravenous opioid analgesics.

SDK is currently being utilized by emergency medicine physicians in the ED for pain control in doses up to 0.3 mg/kg intravenously and up to 1 mg/kg intranasally. Additionally, the use of SDK in the ED is also supported by the American College of Emergency Physicians. While the literature has extensively documented and supported the safety and efficacy of SDK, there is a gap in the literature for its use in the management of pain for minor procedures in the ED. Intranasal ketamine may be a valuable supplement to standard medical treatment in procedures that would not normally require intravenous access. Minor procedures requiring local anesthesia performed in the ED can still be painful including but not limited to suturing, incision and drainage of an abscess, and digital blocks. Traditionally, many of these procedures are completed using only local anesthesia. Soft tissue and/or very large abscess are sometimes not alleviated by local anesthesia alone. The use of intranasal ketamine to alleviate pain during these and other painful procedures may provide patients with more comfort and pain relief than local anesthesia alone. Dosing for chronic pain and acute pain differ in that chronic pain typically requires higher doses than acute pain. Side effects are related to ketamine dosage and administration type. Thus, patients treated for chronic pain with higher doses of SDK often experience more side effects than patients with acute pain treated with lower doses of SDK. Additionally, compared to placebo and opioid groups in various studies, ketamine was associated with greater risk of neurological, psychological, and minor cardiologic effects. However, the opioid groups typically had a higher risk for major cardiopulmonary effects. The most common side effect of intranasal SDK are bad taste in the mouth, dizziness, and sleepiness. A dose of 0.7 mg/kg IN ketamine has been determined to be a suitable analgesic dose for patients with pain in the ED. While studies have shown the efficacy and safety of using ketamine for pain control, no studies to date have looked at its possible use to decrease pain during minor procedures in the ED.

The investigators aim to determine if a sub-dissociative dose of 0.7 mg/kg intranasal ketamine is a desirable choice to reduce pain associated with minor procedures requiring local anesthesia in the ED. These procedures include incision and drainage of an abscess, laceration repairs requiring sutures, nerve blocks (specifically digital nerve blocks), and other minor procedures requiring local anesthesia. The investigators hypothesize that adult and pediatric patients presenting to the ED and undergoing painful minor procedures will report lower pain scores when treated with 0.7 mg/kg intranasal ketamine in addition to standard local anesthesia than patients who receive a volume-based dose of saline solution with standard local anesthesia (control). Additionally, the investigators hypothesize that patients in the treatment cohort will report few side-effects as measured by the Richmond Agitation Sedation Scale (RASS)(i.e., for adult patients) or University of Michigan Sedation Scale (UMSS) (i.e., for pediatric patients). The minor procedures listed above typically require the use of local anesthesia but do not typically require intravenous access. Thus, the use of intranasal ketamine instead of intravenous analgesia minimizes the changes that would be made to the current standard of carrying out these procedures.

In order to avoid a potential confounder of variation in baseline pain severity of the different procedures, only patients undergoing minor procedures that have a similar pain profile will be randomized. Additional aims of the study include decreasing perceived agitation using RASS or UMSS. Collecting data on pain and total discomfort using the NRS-100 point pain scale will provide a unidimensional measurement of patients' subjective interpretation of their pain. The investigators hope to demonstrate that using ketamine at 0.7 mg/kg for associated pain during minor procedures is efficacious and minimizes adverse side effects of ketamine.

• Immediate agitation [Time frame: 15 minutes]
• Acute agitation [Time frame: 30 minutes]
• Delayed agitation [Time frame: 60 minutes]
• Immediate alertness [Time frame: 15 minutes]
• Acute alertness [Time frame: 30 minutes]
• Delayed alertness [Time frame: 60 minutes]