The physiologic effect of the XXXX on radiofrequency ablation.

@entity1707 @entity96 @entity5 @entity516 @entity393 @entity99
BACKGROUND: Radiofrequency ablation (RFA) is gaining widespread acceptance as a safe and effective method for @entity96 ablation. Complete @entity5 ablation is essential for the success of the procedure. Multiple modalities have been explored in an effort to increase the size of the lesion created by RFA. The purpose of this study was to determine the physiologic effects of the @entity516 on RFA lesion size. METHODS: A total of 32 RFA lesions were created in eight @entity1707 . After the induction of anesthesia, pneumoperitoneums of 2, 12, and 24 mmHg were established sequentially in each animal. After an equilibration period of 2 min, RF was administered with a constant saline-infused (0.9%) needle at 25 W for 3 min. In subsequent and complementary experiments, both before and during RF administration at each intraperitoneal pressure (IPP), Doppler flow was measured by laparoscopic ultrasound in the @entity99 while blood pressure was monitored by a femoral arterial line. The animals were then killed humanely and the livers were harvested. Measurements were taken in three dimensions of the ablated areas, and the volume was calculated. Statistical analyses were performed using analysis of variance (ANOVA) and repeated measures test. RESULTS: The average volumes of the lesions (in cm3) were 3.1 +/- 1.8, 5.2 +/- 1.7, and 6.7 +/- 3.3 for IPP of 2, 12 and 24 mmHg, respectively; there was a significant difference between the area of lesion at an IPP of 2 mmHg and an IPP of 24 mmHg ( p < 0.05). Blood flow in the portal vein also decreased significantly from 1.8 +/- 0.6, 0.98 +/- 0.5, and 0.43 +/- 0.2 at IPP of 2, 12, and 24 mmHg, respectively ( p < 0.001). Hepatic artery blood flow and peripheral blood pressure did not change significantly in the respective IPP groups. CONCLUSIONS: This study indicates that the volume of liver ablated by RF can be increased by augmenting the IPP. Our data support the theory that a decrease in portal blood flow results in @entity393 during RFA. The laparoscopic approach to RFA offers the advantage of allowing control of the IPP, which may result in a larger volume of ablated tissue per treatment than can be achieved with the percutaneous technique. These preliminary data on normal hepatic tissue must be confirmed clinically in the setting of @entity99 .
