Does midazolam enhance pain control in prehospital management of traumatic severe pain?

Modulating Influence of State Anxiety on the Effect of Midazolam on Postsurgical Pain

Anxiety contributes to postsurgical pain, and midazolam is frequently prescribed preoperatively. Conflicting results have been described concerning the impact of midazolam on pain. This study aims to evaluate the effect of systemic midazolam on pain after open inguinal hernia repair, clarifying its relationship with preoperative anxiety. A prospective observational cohort study was conducted in three Portuguese ambulatory units between September 2018 and March 2020. Variable doses of midazolam were administered. Postsurgical pain was evaluated up to three months after surgery. We enrolled 306 patients and analyzed 281 patients. The mean preoperative anxiety Numeric Rating Scale score was 4 (3) and the mean Surgical Fear Questionnaire score was 22 (16); the mean midazolam dose was 1.7 (1.1) mg with no correlation to preoperative anxiety scores. Pain ≥4 was present in 67% of patients 24 h after surgery and in 54% at seven days; at three months, 27% were classified as having chronic postsurgical pain. Preoperative anxiety correlated to pain severity at all time points. In multivariable regression, higher midazolam doses were associated with less pain during the first week, with no apparent effect on chronic pain. However, subgroup analyses uncovered an effect modification according to preoperative anxiety: the decrease in acute pain occurred in the low-anxiety patients with no effect on the high-anxiety group. Inversely, there was an increase in chronic postsurgical pain in the very anxious patients, without any effect on the low-anxiety group. Midazolam, generally used as an anxiolytic, might impact distinctively on pain depending on anxiety.

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

INTRODUCTION

Acute pain is a frequent symptom among patients in the pre-hospital setting, and opioids are the most widely used class of drugs for the relief of pain in these patients. However, the evidence base for opioid use in this setting appears to be weak. The aim of this systematic review was to explore the efficacy and safety of opioid analgesics in the pre-hospital setting and to assess potential alternative therapies.

METHODS

The PubMed, EMBASE, Cochrane Library, Centre for Reviews and Dissemination, Scopus, and Epistemonikos databases were searched for studies investigating adult patients with acute pain prior to their arrival at hospital. Outcomes on efficacy and safety were assessed. Risk of bias for each included study was assessed according to the Cochrane approach, and confidence in the evidence was assessed using the GRADE method.

RESULTS

A total of 3453 papers were screened, of which the full text of 125 was assessed. Twelve studies were ultimately included in this systematic review. Meta-analysis was not undertaken due to substantial clinical heterogeneity among the included studies. Several studies had high risk of bias resulting in low or very low quality of evidence for most of the outcomes. No pre-hospital studies compared opioids with placebo, and no studies assessed the risk of opioid administration for subgroups of frail patients. The competency level of the attending healthcare provider did not seem to affect the efficacy or safety of opioids in two observational studies of very low quality. Intranasal opioids had a similar effect and safety profile as intravenous opioids. Moderate quality evidence supported a similar efficacy and safety of synthetic opioid compared to morphine.

CONCLUSIONS

Available evidence for pre-hospital opioid administration to relieve acute pain is scarce and the overall quality of evidence is low. Intravenous administration of synthetic, fast-acting opioids may be as effective and safe as intravenous administration of morphine. More controlled studies are needed on alternative routes for opioid administration and pre-hospital pain management for potentially more frail patient subgroups.

Acute Pain Management

Control of acute pain in oral and maxillofacial surgery is important for patient care and comfort. Oral surgical procedures are associated with tissue injury and inflammation. Acute pain can arise directly from a surgical procedure or from problems such as dental caries, infection, perforation of maxillary sinus, pericoronitis, and jaw fractures. The major factor in acute pain management is deciding on an appropriate intervention and/or analgesics that will provide the best pain relief. Multimodal pain control has taken a leading role in effectively managing acute pain. This article covers the different options available to dental clinicians.

Analgesics for Dental Implants: A Systematic Review

Postsurgical pain is commonly associated with dental and oral surgery, and the use of analgesics has been investigated in the management of postoperative pain. This systematic review summarizes available evidence on analgesics used to manage dental implant surgery postoperative pain, to identify best therapeutic protocols and knowledge gap. A comprehensive search was conducted including MEDLINE/Pubmed, EMBASE, SCOPUS, clinicaltrials.gov, and the Cochrane Database of Systematic Reviews through May 2020. Only randomized controlled trials were included. PRISMA guidelines were followed, and risk of bias was appraised using Cochrane RoB2 tool. Eleven trials (762 patients overall) were included. Some aspects limited the feasibility of a meaningful meta-analysis; thus, a narrative synthesis was conducted. Risk of bias was low in four studies and high in two studies, while five studies raised some concerns due to the randomization process. Analgesic use seemed to be associated with improved postoperative outcomes (pain, patient's satisfaction, and need for rescue medication) when compared to placebo. Overall, this review suggests that the administration of analgesics may provide some advantages in the management of postoperative outcomes after dental implant placement, while indications about the best analgesics cannot be provided.

Prehospital intravenous fentanyl administered by ambulance personnel: a cluster-randomised comparison of two treatment protocols

Background

Prehospital acute pain is a frequent symptom that is often inadequately managed. The concerns of opioid induced side effects are well-founded. To ensure patient safety, ambulance personnel are therefore provided with treatment protocols with dosing restrictions, however, with the concomitant risk of insufficient pain treatment of the patients. The aim of this study was to investigate the impact of a liberal intravenous fentanyl treatment protocol on efficacy and safety measures.

Methods

A two-armed, cluster-randomised trial was conducted in the Central Denmark Region over a 1-year period. Ambulance stations (stratified according to size) were randomised to follow either a liberal treatment protocol (3 μg/kg) or a standard treatment protocol (2 μg/kg). The primary outcome was the proportion of patients with sufficient pan relief (numeric rating scale (NRS, 0–10) < 3) at hospital arrival. Secondary outcomes included abnormal vital parameters as proxy measures of safety. A multi-level mixed effect logistic regression model was applied.

Results

In total, 5278 patients were included. Ambulance personnel following the liberal protocol administered higher doses of fentanyl [117.7 μg (95% CI 116.7–118.6)] than ambulance personnel following the standard protocol [111.5 μg (95% CI 110.7–112.4), P = 0.0001]. The number of patient with sufficient pain relief at hospital arrival was higher in the liberal treatment group than the standard treatment group [44.0% (95% CI 41.8–46.1) vs. 37.4% (95% CI 35.2–39.6), adjusted odds ratio 1.47 (95% CI 1.17–1.84)]. The relative decrease in NRS scores during transport was less evident [adjusted odds ratio 1.18 (95% CI 0.95–1.48)]. The occurrences of abnormal vital parameters were similar in both groups.

Conclusions

Liberalising an intravenous fentanyl treatment protocol applied by ambulance personnel slightly increased the number of patients with sufficient pain relief at hospital arrival without compromising patient safety. Future efforts of training ambulance personnel are needed to further improve protocol adherence and quality of treatment.

Trial registration

ClinicalTrials.gov (NCT02914678). Date of registration: 26th September, 2016.

Midazolam as an active placebo in 3 fentanyl-validated nociceptive pain models

The use of inactive placebos in early translational trials of potentially analgesic compounds is discouraged because of the side-effect profiles of centrally acting analgesics. Therefore, benzodiazepines are used, although their use has not been validated in this context. Whether benzodiazepines confound the results of acute pain tests is unknown. Midazolam (0.06 mg/kg) as an active placebo was investigated in 3 nociceptive models that included contact heat, electrical pain, and pressure pain thresholds in 24 healthy volunteers. Fentanyl (1 μg/kg) served as an internal validator in this randomized, placebo (saline) controlled, 3-way cross-over trial. The primary outcome parameter (contact heat pain) was analyzed using a one-way, repeated measures analysis of variance and Tukey's post test. Midazolam did not reduce pain ([numeric rating scale], 0-100) in a statistically significant manner compared with placebo for the contact heat (mean difference -1.7, 95% confidence interval -10.6 to 7.3; P = 0.89) or electrical pain (4.3, -5.1 to 13.7; P = 0.51) test, nor did it raise the pressure pain thresholds (-28 kPa, -122; 64 kPa, P = 0.73). The width of the confidence intervals suggested that there were no clinically meaningful analgesic effects compared with the placebo. In contrast, the analgesic efficacy of fentanyl was effectively demonstrated in all 3 models (P < 0.01 vs midazolam and placebo). The findings of this study show that midazolam can be used as an active placebo in analgesic drug trials. Furthermore, the proposed models were simple to implement and very effective in detecting analgesia. The test battery can be used in translational trials for new compounds and comes with an active placebo and an optional active comparator.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.