Feasibility and Preliminary Reference Ranges of Invasive Arterial Pressure Monitoring via the Central Auricular Artery in Anesthetized Rabbits

Objective: Anesthesia in rabbits is associated with a high risk of hypotension, which contributes significantly to perioperative mortality. Invasive arterial blood pressure (IABP) monitoring is the gold standard for accurate hemodynamic assessment. The central auricular artery, due to its superficial location, represents a practical site for catheterization. This study aimed to evaluate the technical feasibility of IABP monitoring via the central auricular artery and to establish preliminaryreference ranges for blood pressure values in anesthetized New Zealand White rabbits. Methods: Twenty healthy adult New Zealand White rabbits (mean weight 4.1 ± 0.4 kg) were anesthetized with isoflurane following premedication and induction. A 24-gauge catheter was placed percutaneously in the central auricular artery and connected to a calibrated transducer system. Blood pressure (systolic [SAP], diastolic [DAP], and mean arterial pressure [MAP]), heart rate, and oxygen saturation were recorded every 5 minutes for up to 60 minutes. Results: Successful catheterization was achieved in 19 of 20 rabbits (95% success rate), with one failure due to vessel spasm. No significant changes in vital signs were observed over time (repeated measures ANOVA, P > 0.05). Pooled mean values (± SD; 95% CI for mean; preliminary 95% reference range) were as follows: SAP 82 ± 9 mmHg (78–86 mmHg; 64–100 mmHg), DAP 58 ± 8 mmHg (54–62 mmHg; 42–74 mmHg), MAP 66 ± 8 mmHg (62–70 mmHg; 50–82 mmHg), heart rate 245 ± 28 beats/min (232–258 beats/min; 190–300 beats/min), and SpO2 96 ± 2% (95–97%; 92–100%). Conclusion: Cannulation of the central auricular artery is a highly feasible and reliable method for continuous IABP monitoring in anesthetized rabbits. The preliminary reference ranges and corresponding 95% confidence intervals we report here match the typical drops seen under anesthesia versus awake states, offering a useful guide for spotting hypotension (like when MAP dips below 60 mmHg).