Heat production during pulmonary artery sealing with energy vessel-sealing devices in a swine model

Abstract

OBJECTIVES Energy vessel-sealing devices are being increasingly utilized to seal pulmonary artery (PA) branches during lobectomy. Heat from these devices can potentially injure surrounding tissues. We evaluated heat production from devices in a live animal model. METHODS PA branches were sealed in pigs with 4 energy vessel-sealing devices: 2 ultrasonic (US), 1 advanced bipolar or 1 mixed US and bipolar (mixed) device. Thermocouples were implanted in tissue surrounding the PA branch being sealed to measure tissue temperature. A thermal camera measured the sealing site and the temperatures of the instruments. Pathological analysis was performed on PA stumps to identify thermal damage. RESULTS A total of 37 PA branches were sealed in 4 pigs. Maximum tissue heat measured by the thermocouples for the 2 US, advanced bipolar and mixed devices was 42, 39, 42 and 46°C, respectively. The mean tissue temperatures at the site of the sealing measured with the thermal camera were 78, 75, 70 and 82°C (P = 0.834) and the mean instrument blade temperatures were 224, 195, 83 and 170°C (P = 0.000005) for the 2 US, advanced bipolar and mixed devices, respectively. The mean diameter of the region with tissue reaching 60°C or more measured with the thermal camera was between 4 and 6 mm for the 4 devices (P = 0.941). On pathological analysis, PA stumps had either thermal damage on the adventitia and external media (26/37) or transmural damage (11/37) at 1 mm from sealed site. CONCLUSIONS A 3-mm safety margin between the instrument blades and vital structures is recommended. Instrument blades can reach high temperatures that may cause tissue damage.

Energy devices for pulmonary artery sealing in video-assisted thoracoscopic surgery (VATS) segmentectomy: literature review and surgical technique

“…In human ex-vivo PA sealing model, the mean bursting pressure of ultrasonic devices was twice as high as bipolar devices (Harmonic 416 mmHg, LiGasure 215 mmHg, EnSeal 134 mmHg) (12). In animal model, the mean tissue temperatures during PA sealing is about the same in ultrasonic and bipolar devices (70-78 ℃) but the instrument blade temperature is much higher in ultrasonic devices (224 vs. 83 ℃) (18). In histological and immunohistochemical analysis of pulmonary vessels divided by LigaSure, it was found that LigaSure sealing result in sealing of the adventitia only, without complete fusion of the layers of the PA walls.…”

“…To prevent premature division of the artery, it is very important to avoid tension or torsion for the entire activation. At the end of sealing, the instrument tip can reach temperatures exceeding 200 ℃ (18). To avoid a thermal injury for adjacent vessels, airway and parenchyma, it is critically important to maintain a short distance away from the surrounding tissue during activation, and to cool the instrument on the lung to be removed before using it for subsequent dissection.…”