Hemodynamic changes during laparoscopic radiofrequency ablation of normal adrenal tissue in dogs.

Objective: To determine the hemodynamic response to radiofrequency ablation (RFA) of normal adrenal tissue in dogs.

Study Design: Experimental study.

Animals: Healthy adult mixed-breed dogs (n=6).

Methods: During general anesthesia a Swan-Ganz thermodilution catheter was flow directed into the pulmonary artery and used to quantify cardiac output. An arterial catheter was used for direct blood pressure measurements. An RFA device was introduced into the left adrenal gland under observation through laparoscopic instrumentation. Blood samples were collected and hemodynamic variables studied after a stable surgical anesthetic depth was achieved (time 1), during CO(2) insufflation of the abdomen (time 2), during adrenal RFA (time 3), and after completed RFA (time 4). Catecholamine determinations were performed with a human enzyme immunoassay. Histopathology was performed to verify medullary necrosis.

Results: Arterial, pulmonary arterial and central venous pressure, and plasma norepinephrine increased more during RFA than during abdominal insufflation. Heart rate and cardiac index did not differ between time points. High baseline epinephrine was present and significant differences between time points were not detected. Systemic vascular resistance had very high individual variation and differences were not detected.

Conclusions: RFA of normal adrenal tissues is associated with severe hemodynamic alterations. Further studies of the optimal blockage of catecholamine-induced hypertension in dogs are warranted.

Clinical Relevance: Clinicians should prepare for potential hypertensive crisis during RFA of adrenal masses, especially if treating a margin of normal tissue.