Why prehospital analgesia should follow a structured approach
Severe pain after trauma, from fractures, burns or dislocations, is one of the most common reasons for dispatching an emergency physician. Consistent pain management in the emergency medical service improves comfort, enables immobilisation, reduction and technical rescue, and facilitates cooperation. At the same time, every analgosedation balances adequate effect against respiratory depression, haemodynamic instability or loss of protective airway reflexes. Deliberate drug selection, titrated administration and continuous monitoring are therefore essential.
Pain assessment as the starting point
Before the first dose, pain intensity is assessed with a validated instrument, in adults usually the numerical rating scale (NRS) or a visual analogue scale. Where communication is limited (children, dementia, language barrier), observer-rated scales are used. The target value and the intervention threshold depend on the local SOP and the current guideline. Complete freedom from pain is not always achievable. A marked reduction that the patient perceives as adequate is the realistic goal.
Non-pharmacological measures precede or accompany drug therapy: pain-relieving positioning, splinting and immobilisation, cooling of burns and calm communication.
Esketamine: ketamine analgesia in emergency physician practice
In German-speaking countries, the term ketamine analgesia in emergency physician practice frequently refers to the S-enantiomer esketamine. The following doses refer exclusively to esketamine. They cannot be transferred to racemic ketamine, for which the summary of product characteristics of the respective product applies.
Analgesic dosing (summary of product characteristics)
- 0.13–0.25 mg/kg i.v., slowly, preferably using the 5 mg/ml concentration
- 0.25–0.5 mg/kg i.m., using the 25 mg/ml concentration
| BW | i.v. (5 mg/ml) | i.m. (25 mg/ml) |
|---|---|---|
| 60 kg | 7.5–15 mg = 1.5–3 ml | 15–30 mg = 0.6–1.2 ml |
| 80 kg | 10–20 mg = 2–4 ml | 20–40 mg = 0.8–1.6 ml |
| 100 kg | 12.5–25 mg = 2.5–5 ml | 25–50 mg = 1–2 ml |
Caution: Esketamine is marketed in two concentrations (5 and 25 mg/ml). Check the ampoule before drawing up the drug. A mix-up results in a fivefold dosing error.
Strengths and limitations
- Sympathomimetic action, therefore usually stabilising haemodynamics. In catecholamine-depleted patients in shock, however, negative inotropy is possible.
- Protective reflexes and spontaneous breathing are largely preserved. This does not, however, guarantee a secure airway.
- According to the summary of product characteristics, the dose should be reduced in polytrauma and in patients with poor general condition.
- Typical adverse effects are emergence reactions with nightmares and hypersalivation, particularly in children.
Contraindications (selection according to the summary of product characteristics)
- situations in which a rise in blood pressure or intracranial pressure poses a serious risk
- untreated or poorly controlled arterial hypertension
- pre-eclampsia/eclampsia, untreated hyperthyroidism
- as the sole anaesthetic in manifest coronary artery disease
- situations requiring a relaxed uterus
Regarding intracranial pressure: under controlled ventilation with normocapnia, current evidence shows no relevant rise in ICP. The summary of product characteristics nevertheless remains authoritative.
Opioids: fentanyl as a titratable standard analgesic
Fentanyl is a µ-agonist with a rapid onset of action and approximately 100 times the potency of morphine.
Dosing during spontaneous breathing, adults (summary of product characteristics)
- 50–200 µg i.v. initially, repeat dose 50 µg as required (preparation 50 µg/ml, corresponding to 1–4 ml)
- In the prehospital setting, start low, e.g. with 50 µg, and titrate to effect.
- Reduce the dose in older patients, in hypovolaemia and with concomitant sedatives.
Adverse effects and pitfalls
- Respiratory depression: may outlast analgesia. The antagonist naloxone has a shorter duration of action than fentanyl, so renarcotisation is possible and monitoring must be continued. Refer to the current summary of product characteristics for naloxone dosing.
- Chest wall rigidity: possible with rapid injection of higher doses. Inject slowly. In extreme cases, neuromuscular blockade is required.
- Circulation: bradycardia and hypotension, particularly in hypovolaemia.
- Other: nausea. Effects are potentiated by benzodiazepines, hypnotics and CYP3A4 inhibitors.
Fentanyl is contraindicated in hypersensitivity to opioids and in respiratory depression where ventilation is not possible. Other opioids such as morphine or piritramide are also established in some regions. Their dosing follows the respective summary of product characteristics and the local SOP.
Non-opioids: foundation and supplement
Metamizole, paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) are suitable primarily for moderate pain, for colic, or as a foundation to spare opioids. In the prehospital setting, the following points should be considered:
- Metamizole: hypotension is possible with rapid injection, so give slowly or as a short infusion. Agranulocytosis is rare but serious.
- Paracetamol: take liver disease and body weight into account when determining the dose.
- NSAIDs: use with caution in relevant bleeding, renal impairment, hypovolaemia and gastrointestinal risk.
Refer to the current summary of product characteristics for specific doses. The onset of action is slower than that of esketamine or fentanyl. In severe trauma pain, non-opioids alone are usually insufficient.
Routes of administration
- Intravenous: standard route, as it is readily titratable with a rapid onset. If venepuncture fails, intraosseous access is an established alternative.
- Intramuscular: provided for in the summary of product characteristics for esketamine. Useful with difficult vascular access or during technical rescue, but less controllable.
- Intranasal: described for individual substances. Refer to the summary of product characteristics or the local SOP for licensing status, dosing and application technique.
Combinations: additive efficacy, additive risk
- Esketamine plus opioid: this combination is widespread in practice and may help keep each individual dose low. Titrate each substance separately and wait for the effect each time.
- Esketamine plus low-dose benzodiazepine or propofol: to be considered according to the summary of product characteristics to reduce emergence reactions. The risk of respiratory depression increases.
- Opioid plus benzodiazepine: marked potentiation, therefore reduce doses and monitor closely. Flumazenil antagonises only benzodiazepines (and Z-drugs), not opioids, alcohol or barbiturates. Because of its short half-life, resedation is possible.
- Non-opioid as a foundation: may reduce opioid requirements. Evidence for the prehospital benefit of individual combinations is limited.
The transition from analgosedation to general anaesthesia is fluid. If general anaesthesia becomes necessary (esketamine induction dose 0.5–1 mg/kg i.v.), full RSI preparation and the Plan A–D airway algorithm apply.
Monitoring during pain management
- Continuous SpO₂ and ECG, blood pressure at short intervals.
- Capnography (etCO₂), ideally also during spontaneous breathing via nasal sampling. It detects hypoventilation earlier than pulse oximetry, particularly during oxygen administration.
- Assess level of consciousness and respiratory rate clinically and serially.
- Keep a bag-valve-mask, suction (hypersalivation with esketamine), oxygen and antagonists immediately available.
- Secure, running vascular access.
Documentation of the pain course
Structured documentation supports patient safety, handover and quality assurance. It includes:
- pain score before the first dose, after each dose and at handover, each with the time
- substance (active ingredient), concentration, single and cumulative dose, route of administration
- vital signs and level of consciousness in relation to the time of administration
- adverse effects and their treatment, e.g. antagonism or antiemetic therapy
- reasons for dose reduction or for withholding analgesia
Key points for practice
- Assess pain before every dose and reassess after every dose.
- Esketamine is an option in haemodynamic instability and during technical rescue. Check the ampoule concentration.
- Start fentanyl low and titrate. Respiratory depression may outlast analgesia.
- Use non-opioids as a foundation, dosing not from memory but according to the summary of product characteristics.
- Use combinations deliberately and maintain consistent monitoring, including capnography.
References
- Fachinformation Esketamin 5 mg/ml / 25 mg/ml Injektionslösung (Pfizer) – aktuelle Fassung.
- Fachinformation Fentanyl 0,05 mg/ml Injektionslösung (Fentanylcitrat) – aktuelle Fassung.
- Fachinformationen Flumazenil 0,1 mg/ml Injektionslösung – aktuelle Fassung prüfen.
- Difficult Airway Society 2025 guidelines for management of unanticipated difficult tracheal intubation in adults. Br J Anaesth 2025 (Epub 07.11.2025), Algorithmus Plan A–D.
This article does not replace clinical judgement in the individual case or the current summary of product characteristics and guidelines.
