Small doses of adrenaline contained in the local anaesthetic may result in prolonged increased cardiac function even after the vital signs return to normal

Introduction: The effects of adrenaline contained in the local anaesthetic on vital signs have been reported under general anaesthesia or sedation. The ClearSight™ system measures cardiac parameters, including cardiac index, stroke volume, systemic vascular resistance index, continuous blood pressure, and heart rate, non-invasively and continuously. Aim: This study aimed to assess the effect of adrenaline contained in the local anaesthetic on cardiac function in conscious participants. Materials and methods: Eight healthy adults were recruited for the study. Local anaesthesia was administered to the maxillary gingiva using 3.6 mL of 2% lidocaine with 1/80,000 of adrenaline (group AD) or without adrenaline (group non-AD) on separate days. The above listed cardiac parameters were recorded with the ClearSight™ system. All data were continuously monitored until these values returned to normal levels. Results: The cardiac index and heart rate increased by 40% in group AD. Moreover, the cardiac index and systemic vascular resistance index in group AD required 50 min to recover to the pre-injection levels. Heart rate variations showed no intergroup differences, and variations in systolic continuous blood pressure persisted for only 30 min. Conclusions: The effect of anaesthetic injection containing adrenaline on cardiac function may persist even after the vital signs return to normal.