Low-dose S-ketamine for prehospital pain relief.

Abstract

Introduction: S-ketamine is increasingly used as an adjunct to opioids for prehospital traumatic pain, but data on patient experience and safety in civilian paramedic practice remain limited. We evaluated low-dose S-ketamine, alone or with fentanyl, in a Danish prehospital setting.

Methods: This was a prospective observational study including adult prehospital patients with pain from significant trauma, suspected fractures of long bones, spine or pelvis, or joint dislocations. Paramedics administered intravenous S-ketamine, usually after fentanyl, and recorded pain using a numerical rating scale (NRS) and an electronic questionnaire on efficacy, side effects and patient experience. Data completeness was ensured by twice-weekly electronic record searches and follow-up.

Results: Among 348 patients, 320 (92.0%) reported effective pain relief, with a median NRS reduction of five points. In the combination group, the median fentanyl dose was 150 µg (IQR: 100-200 µg), and the median ketamine dose was 10 mg (IQR: 10-20 mg). In the monotherapy group, the median ketamine dose was 15 mg (IQR: 10-20 mg). Hallucinations occurred in 30.0% (23.9% positive, 6.0% negative) and diplopia in 9.2%. Blood pressure changes > 20 mmHg occurred in 10.1% and tachycardia in 8.0%, with no serious adverse events. Overall, 93.2% stated they would accept S-ketamine again.

Conclusions: In this prospective observational cohort, low-dose S-ketamine, administered alone or in combination with fentanyl, was associated with effective prehospital analgesia, infrequent and predominantly benign side effects and high patient satisfaction.

Funding: None.

Trial registration: Not relevant.