Opioids for Treatment of Pre-hospital Acute Pain: A Systematic Review

Alfentanil for Pain Relief in a Swedish Emergency Medical Service - An Eleven-Year Follow-up on Safety and Effect

OBJECTIVES

Pain is a common symptom in prehospital emergency care and pain treatment in this context can be challenging. While previous research has assessed the use of morphine and other synthetic opioids for pain management in this setting, the evaluation of alfentanil is limited. The objective of this study was to evaluate the safety and effect of intravenous alfentanil when administered by ambulance nurses in prehospital emergency care.

METHODS

This retrospective observational study consecutively included patients suffering from pain, treated with alfentanil in a Swedish EMS service from September 2011 to 31 September 2022. Data regarding occurrence of adverse events (AE), serious adverse events (SAE) - were used for safety evaluation and pain scores with a visual analogue scale (VAS) before and after treatment were used for evaluation of pain treatment. These data were extracted from the electronic patients' medical records database for analysis. Univariate logistic regression analysis was used to identify significant predictors of AE following injection of alfentanil by nurses in prehospital emergency care.

RESULTS

During the evaluation period 17,796 patients received pain relief with alfentanil. Adverse events affected 2.5% of the patients, while serious adverse events were identified in 25 cases (0.01%). Out of the 5970 patients with a complete VAS score for pain, the median VAS score was 8 (IQR 3) before treatment and 4 (IQR 3) after treatment. The mean reduction in pain measured by VAS was -4.1 ± 2.6 from the time before, to the evaluation after alfentanil administration. The administration frequency increased during the first year up to a steady level during the later part of the evaluation period.

CONCLUSIONS

This study proposes that alfentanil represents a safe and efficacious alternative for addressing urgent pain relief within the prehospital emergency context. Alfentanil demonstrates efficacy in alleviating pain across various conditions, with a relatively low risk of adverse events or serious adverse events when administered cautiously.

Ketamine Compared With Morphine for Out-of-Hospital Analgesia for Patients With Traumatic Pain: A Randomized Clinical Trial

Importance

Pain is a common out-of-hospital symptom among patients, and opioids are often prescribed. Research suggests that overprescribing for acute traumatic pain is still prevalent, even when limits restricting opioid prescriptions have been implemented. Ketamine hydrochloride is an alternative to opioids in adults with out-of-hospital traumatic pain.

Objective

To assess the noninferiority of intravenous ketamine compared with intravenous morphine sulfate to provide pain relief in adults with out-of-hospital traumatic pain.

Design, Setting, and Participants

The Intravenous Subdissociative-Dose Ketamine Versus Morphine for Prehospital Analgesia (KETAMORPH) study was a multicenter, single-blind, noninferiority randomized clinical trial comparing ketamine hydrochloride (20 mg, followed by 10 mg every 5 minutes) with morphine sulfate (2 or 3 mg every 5 minutes) in adult patients with out-of-hospital trauma and a verbal pain score equal to or greater than 5. Enrollment occurred from November 23, 2017, to November 26, 2022, in 11 French out-of-hospital emergency medical units.

Interventions

Patients were randomly assigned to ketamine (n = 128) or morphine (n = 123).

Main Outcomes and Measures

The primary outcome was the between-group difference in mean change in verbal rating scale pain scores measured from the time before administration of the study drug to 30 minutes later. A noninferiority margin of 1.3 was chosen.

Results

A total of 251 patients were randomized (median age, 51 [IQR, 34-69] years; 111 women [44.9%] and 140 men [55.1%] among the 247 with data available) and were included in the intention-to-treat population. The mean pain score change was -3.7 (95% CI, -4.2 to -3.2) in the ketamine group compared with -3.8 (95% CI, -4.2 to -3.4) in the morphine group. The difference in mean pain score change was 0.1 (95% CI, -0.7 to 0.9) points. There were no clinically meaningful differences for vital signs between the 2 groups. The intravenous morphine group had 19 of 113 (16.8% [95% CI, 10.4%-25.0%]) adverse effects reported (most commonly nausea [12 of 113 (10.6%)]) compared with 49 of 120 (40.8% [95% CI, 32.0%-49.6%]) in the ketamine group (most commonly emergence phenomenon [24 of 120 (20.0%)]). No adverse events required intervention.

Conclusions and Relevance

In the KETAMORPH study of patients with out-of-hospital traumatic pain, the use of intravenous ketamine compared with morphine showed noninferiority for pain reduction. In the ongoing opioid crisis, ketamine administered alone is an alternative to opioids in adults with out-of-hospital traumatic pain.

Trial Registration

ClinicalTrials.gov Identifier: NCT03236805.

Comparison of three regimens with inhalational methoxyflurane versus intranasal fentanyl versus intravenous morphine in pre-hospital acute pain management: study protocol for a randomized controlled trial (PreMeFen)

BACKGROUND

Pre-hospital pain management has traditionally been performed with intravenous (IV) morphine, but oligoanalgesia remain a recognized problem. Pain reduction is essential for patient satisfaction and is regarded as a measure of successful treatment. We aim to establish whether non-invasive methods such as inhalation of methoxyflurane is non-inferior to intranasal fentanyl or non-inferior to the well-known IV morphine in the pre-hospital treatment of acute pain.

METHOD/DESIGN

The PreMeFen study is a phase three, three-armed, randomized, controlled, non-inferiority trial to compare three regimens of analgesics: inhalation of methoxyflurane and intranasal (IN) fentanyl versus IV morphine. It is an open-label trial with a 1:1:1 randomization to the three treatment groups. The primary endpoint is the change in pain numeric rating scale (NRS) (0-10) from baseline to 10 min after start of investigational medicinal product administration (IMP). The non-inferiority margin was set to 1.3, and a sample size of 270 patients per protocol (90 in each treatment arm) will detect this difference with 90% power.

DISCUSSION

We chose a study design with comparison of analgesic regimens rather than fixed doses because of the substantial differences in drug characteristics and for the results to be relevant to inform policymakers in the pre-hospital setting. We recognize that easier administration of analgesics will lead to better pain management for many patients if the regimens are as good as the existing, and hence, we chose a non-inferiority design. The primary endpoint, the change in pain (NRS) after 10 min, is set to address the immediate need of pain reduction for patients with acute prehospital pain. On a later stage, more analgesic methods are often available. PreMeFen is a non-inferiority randomized controlled trial comparing three analgesic regimens aiming to establish whether inhalation of methoxyflurane or intranasal fentanyl is as good as IV morphine for fast reduction of acute pain in the prehospital setting.

Evaluation of Nonintubated Analgesia Practices in Critical Care Transport

OBJECTIVE

Current analgesia recommendations in the prehospital setting are not specific to critical care transport. Variation exists in the recommended agent and dosing strategies. Furthermore, there is a paucity of literature evaluating benzodiazepine and opiate coadministration, which may place patients at risk for respiratory decompensation.

METHODS

This was a retrospective chart review of nonintubated adult critical care transport patients between July 1, 2020, and July 1, 2022, who received fentanyl or ketamine during transport. The primary outcome was the proportion of patients oversedated. The secondary outcomes were characterization of analgesic medication use during transport, the percentage of patients coadministered benzodiazepines, naloxone administration, and escalation of respiratory intervention.

RESULTS

Three hundred seventy-six patients were administered fentanyl or ketamine during transport. Eleven patients were oversedated. Three hundred twenty-four patients received fentanyl monotherapy, and 52 received combination therapy. Patients who received benzodiazepines had higher odds of oversedation (odds ratio = 5.75; 95% confidence interval, 1.6-20.7). Two hundred thirty-six patients required an escalation in respiratory support, most commonly an increase from room air to nasal cannula. No patients had naloxone administered.

CONCLUSION

The rate of oversedation of nonintubated adult critical care transport patients receiving fentanyl or ketamine is low. Coadministration of benzodiazepines increases the risk of oversedation.

The Pain Management of Trauma Patients in the Emergency Department

The vast majority of injured patients suffer from pain. Systematic assessment of pain on admission to the emergency department (ED) is a cornerstone of translating the best treatment strategies for patient care into practice. Pain must be measured with severity scales that are validated in clinical practice, including for specific populations (such as children and older adults). Although primary care ED of trauma patients focuses on resuscitation, diagnosis and treatment, pain assessment and management remains a critical element as professionals are not prepared to provide effective and early therapy. To date, most EDs have pain assessment and management protocols that take into account the patient's hemodynamic status and clinical condition and give preference to non-pharmacological approaches where possible. When selecting medications, the focus is on those that are least disruptive to hemodynamic status. Pain relief may still be necessary in hemodynamically unstable patients, but caution should be exercised, especially when using opioids, as absorption may be impaired or shock may be exacerbated. The analgesic dose of ketamine is certainly an attractive option. Fentanyl is clearly superior to other opioids in initial resuscitation and treatment as it has minimal effects on hemodynamic status and does not cause central nervous system depression. Inhaled analgesia techniques and ultrasound-guided nerve blocks are also increasingly effective solutions. A multimodal pain approach, which involves the use of two or more drugs with different mechanisms of action, plays an important role in the relief of trauma pain. All EDs must have policies and promote the adoption of procedures that use multimodal strategies for effective pain management in all injured patients.