Background Ketamine is an induction agent frequently used for general anaesthesia in emergency medicine. Generally regarded as haemodynamically stable, it can cause hypertension and tachycardia and may cause or worsen shock. The effects of ketamine may be improved by the addition of fentanyl to the induction regime. We conducted a systematic review to identify evidence with regard to the effect of adding fentanyl to an induction regime of ketamine and a paralysing agent on post‐induction haemodynamics, intubating conditions and mortality. Methods We conducted a search of the Cochrane library, EMBASE, MEDLINE, PROQUEST, OpenGrey and clinical trial registries. Prominent authors were contacted in order to identify additional literature pertinent to the research question. Studies were included if they pertained to intubation of adult patients in the prehospital or emergency department environments and included an induction regime of ketamine and a paralysing agent, with at least one outcome measure of haemodynamics, intubating conditions or mortality. Search results were reviewed by two investigators independently, adjudicated by a third investigator where disagreement occurred. Results One observational study was identified that partially answered the research question. Discussion Only one observational study was identified that partially answered the research question. This paper demonstrated that the use of fentanyl as a pretreatment increases the incidence of post‐induction hypotension, a phenomenon that was seen with propofol, midazolam and ketamine. The difference in hypotension between these agents was not statistically significant. The impact of this on patient‐orientated outcomes is unclear.

Background Ketamine use for rapid sequence intubation (RSI) is frequent in pre‐hospital and retrieval medicine (PHARM) and is associated with potentially deleterious haemodynamic changes, which may be ameliorated by concurrent use of fentanyl. Objectives To describe the frequency with which fentanyl is used in conjunction with ketamine in a system where its use is discretionary, and to explore any observed changes in haemodynamics with its use. Methods A retrospective observational study of over 800 patients undergoing RSI with ketamine ± fentanyl in the PHARM setting between 2015 and 2019. The primary outcome was the proportion of patients in each group who had a systolic blood pressure (SBP) outside a pre‐specified target range, with adjustment for baseline abnormality, within 10 min of anaesthetic induction. Results Eight hundred and seventy‐six patients were anaesthetised with ketamine, of whom 804 were included in the analysis. 669 (83%, 95% CI 80%–86%) received ketamine alone, and 135 (17%, 95% CI 14%–20%) received both fentanyl and ketamine. Median fentanyl dose was 1.1 mcg/kg (IQR 0.75–1.5 mcg/kg). Systolic blood pressure (SBP) at induction was consistently associated with SBP after intubation in multivariable logistic regression, but fentanyl use was not associated with a change in odds of meeting the primary outcome (OR 1.08; 95% CI 0.72–1.60), becoming hypertensive (OR 1.35; 95% CI 0.88–2.07) or hypotensive (OR 0.76; 95% CI 0.47–1.21). Conclusions The addition of fentanyl to ketamine for RSI was not associated with an alteration of the odds of post‐induction haemodynamic stability, although the doses used were low. These findings justify further study into the optimal dosing of fentanyl during RSI in pre‐hospital and retrieval medicine.