Thermochemical Ablation in an Ex-vivo Porcine Liver Model Using Acetic Acid and Sodium Hydroxide: Proof of Concept

• Published in: Journal of vascular and interventional radiology Vol. 21; no. 10; pp. 1573 - 1578
• Main Authors: Farnam, Joseph L., BS, Smith, Benjamin C., MD, Johnson, Brandon R., MD, Estrada, Rodolfo, BS, Edelman, Theresa L., BS, Farah, Rina, BS, Cressman, Erik N.K., MD, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2010
• Subjects: Acetic Acid - administration & dosage; Animals; Dose-Response Relationship, Drug; Liver - drug effects; Liver - pathology; Liver - surgery; Pilot Projects; Radiology; Sclerosing Solutions - administration & dosage; Sodium Hydroxide - administration & dosage; Swine
• ISSN: 1051-0443; 1535-7732
• DOI: 10.1016/j.jvir.2010.06.012

Purpose To establish proof of concept in tissue, using the exothermic neutralization reaction of acetic acid and sodium hydroxide in ex vivo porcine liver and to conduct an initial probe into the relationships of volume and concentration of reagents to temperatures and the areas affected. Materials and Methods A total of 0.5 mL or 2 mL of either 5 mole/L or 10 mole/L acid and base solutions was injected simultaneously into the periphery of ex vivo porcine liver using a prototype injection device. Tissue temperature was recorded at the injection site for 5 minutes using a type T thermocouple temperature probe inserted parallel to and near the tip of the injection device. The injections were repeated for infrared thermography, and ablated tissues were sectioned quickly and imaged. A gross photograph was captured in each case to provide correlation. Results Maximum temperatures (17°C baseline) ranged from 42.1° ±α3.34°C to 61.7° ±α10°C ( P <.05) when injecting 0.5 mL of 5 mole/L reactants and 2 mL of 10 mole/L reactants, respectively. The maximum temperature measured by infrared imaging ranged from 31°–47°C. Using an infrared viewing scale from 19°–40°C, the cross-sectional area of tissue heating above baseline measured from 1.07 cm2 ± 0.45 to 4.95 cm2 ± 0.28 ( P <05). Conclusions The reaction of acetic acid and sodium hydroxide releases significant heat energy at the site of injection, and histologic changes are consistent with coagulation necrosis. Increased reagent concentration and volume were associated with larger temperature changes and larger areas of hyperthermia at gross pathology and infrared imaging.