title: Minimizing diaphragmatic injury during radiofrequency ablation: efficacy of intraabdominal carbon dioxide insufflation.
abstract: OBJECTIVE
  The purpose of our study was to determine whether intraperitoneal insufflation of carbon dioxide (CO(2)) reduces adjacent diaphragmatic injury.
  
  
  METHODS
  In seven pigs under anesthesia, a 17-gauge percutaneous insufflation needle was inserted in the infraumbilical midline using a standard insufflator. Three to six liters of CO(2) was infused into the peritoneal space to achieve at least a 1-cm separation between the liver and the diaphragm and maintained by a pressure of 8-10 mm Hg. Seven control lesions in six historical controls were used. In addition, five lesions were created in one animal from this cohort who served as a control. Superficial areas of liver separated from diaphragm were fluoroscopically targeted for radiofrequency ablation, and several 2-cm-diameter radiofrequency lesions were generated. The pigs were sacrificed at 48 hr, and at laparotomy, the liver surface was inspected and sectioned to select lesions with centers within 1 cm of the surface. The thermal injury to the corresponding adjacent diaphragm was examined to determine the depth of injury. Diaphragmatic injury was graded on a scale from 0 to III (0, no injury; I, mild injury to one-third thickness; II, moderate injury to two-thirds thickness; III, severe injury to full thickness.)
  
  
  RESULTS
  Of 72 total lesions created, 60 had centers less than 1 cm from the liver surface (i.e., superficial) at laparotomy. Of these 60 lesions, 55 caused no significant diaphragmatic injury, two caused grade I injury and three caused grade III injury. In comparison, seven of seven historic superficial control lesions and five of five superficial radiofrequency control lesions from the current cohort caused grade III injury. Superficial radiofrequency lesions created after intraperitoneal CO(2) insufflation caused significantly less (p < 0.01) diaphragmatic injury.
  
  
  CONCLUSIONS
  We have shown that in pigs, intraperitoneal CO(2) insufflation helped significantly reduce severe diaphragmatic injury when superficial hepatic radiofrequency ablation was performed.
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, BL-428 CHS/Box 951721, Los Angeles, CA 90095-1721, USA. sraman@mednet.ucla.edu
authors.forename: Steven S
authors.initials: SS
authors.lastname: Raman
authors.forename: Donya
authors.initials: D
authors.lastname: Aziz
authors.forename: Xinlan
authors.initials: X
authors.lastname: Chang
authors.forename: James
authors.initials: J
authors.lastname: Sayre
authors.forename: Charles
authors.initials: C
authors.lastname: Lassman
authors.forename: David
authors.initials: D
authors.lastname: Lu
mesh_terms: D000818:Animals; D002245:Carbon Dioxide; D017115:Catheter Ablation; D003964:Diaphragm / Q000293:injuries*; D007327:Insufflation; D007431:Intraoperative Complications / Q000628:therapy*; D008099:Liver / Q000601:surgery; D013552:Swine
chemical_list: D002245:Carbon Dioxide