title: Impact of pneumoperitoneum on renal cryotherapy.
abstract: OBJECTIVE
  Pneumoperitoneum is known to decrease blood flow to the kidney during laparoscopy. We investigated if this change in blood flow would increase the size of the cryolesion.
  
  
  METHODS
  Twelve Yorkshire swine underwent laparoscopy-guided percutaneous cryoablation of the upper and lower pole of each kidney at four randomized pneumoperitoneum pressures (10, 15, 20, and 25 mm Hg). Cryolesions were made with a 1.47-mm IceRod (Galil Medical, Plymouth Meeting, PA). Each site underwent two 10-minute freeze cycles separated by a 5-minute active thaw with pressurized helium gas. At the conclusion of each freeze cycle, the iceball volume was measured with intraoperative ultrasound. After completion of the four cryolesions, the kidneys were harvested, and the cryolesion surface area was calculated. The lesions were fixed in 10% buffered formalin and then excised with a 1-mm margin to obtain a volume measurement using fluid displacement.
  
  
  RESULTS
  Iceball volume was 3.41, 2.85, 3.44, and 2.36 cm(3) for freeze cycle 1 (p = 0.16) and 3.67, 3.34, 4.88, 3.95 cm(3) for freeze cycle 2 (p = 0.20) at 10, 15, 20, and 25 mm Hg, respectively. Cryolesion volume by fluid displacement was 4.06, 3.77, 3.97, and 3.93 cm(3) (p = 0.86) and cryolesion surface area was 4.55, 4.38, 4.39, and 4.20 cm(2) (p = 0.71) at 10, 15, 20, and 25 mm Hg, respectively.
  
  
  CONCLUSIONS
  In this study, pneumoperitoneum pressure between 10 and 25 mm Hg did not affect iceball size as measured by intraoperative ultrasound, cryolesion volume by fluid displacement, or cryolesion surface.
authors.affiliation: Department of Urology, University of California Irvine, Orange, California, USA. jlyoung@uci.edu
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Young
authors.forename: Michael K
authors.initials: MK
authors.lastname: Louie
authors.forename: Cervando G
authors.initials: CG
authors.lastname: Ortiz-Vanderdys
authors.forename: David W
authors.initials: DW
authors.lastname: McCormick
authors.forename: Victor B
authors.initials: VB
authors.lastname: Huynh
authors.forename: Adam G
authors.initials: AG
authors.lastname: Kaplan
authors.forename: Nick S
authors.initials: NS
authors.lastname: Jain
authors.forename: Donald L
authors.initials: DL
authors.lastname: Pick
authors.forename: Lorena A
authors.initials: LA
authors.lastname: Andrade
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Osann
authors.forename: Surendra B
authors.initials: SB
authors.lastname: Kolla
authors.forename: Petros
authors.initials: P
authors.lastname: Sountoulides
authors.forename: Oskar G
authors.initials: OG
authors.lastname: Kaufmann
authors.forename: Elspeth M
authors.initials: EM
authors.lastname: McDougall
authors.forename: Ralph V
authors.initials: RV
authors.lastname: Clayman
mesh_terms: D000818:Animals; D017679:Cryotherapy; D005260:Female; D007430:Intraoperative Care; D007668:Kidney / Q000000981:diagnostic imaging / Q000601:surgery*; D011027:Pneumoperitoneum / Q000000981:diagnostic imaging / Q000601:surgery*; D013552:Swine; D014463:Ultrasonography