133Xe clearance estimates the effect of vasopressin on peritoneal blood flow in rats.
OBJECTIVE
When assessing the peritoneal microcirculation with invasive methods, interference with the mechanisms of vaso-regulation may occur. The 133Xe clearance technique renders the possibility, by minimal invasiveness, to estimate the influence of a vasoactive agent on the peritoneal microcirculation.


METHODS
Ten to 15MBq of 133Xe were injected in the abdominal cavity in thirty-eight Wistar-FU (W-FU) rats and 35 Lister-Hooded (LH) rats. A NaI (Tl)-scintillation detector registered activity before and during vasopressin infusion. Gamma camera imaging confirmed the washout from the abdominal cavity. The laser Doppler flowmetry technique was used as a comparison.


RESULTS
Vasopressin at 0.07 IU/kg/min IV significantly reduced 133Xe-clearance by 37% (p = 0.029) and 52% (p=0.036) and laser Doppler flowmetry by 69% (p=0.0019) and 44% (p=0.0039) in W-FU and LH rats, respectively. A linear correlation between dose of vasopressin and relative decrease in 133Xe clearance was demonstrated in the W-FU rat model (r2=0.98, p=0.023). The 133Xe clearance from the abdominal cavity in rat using a single-compartment model or the slow compartment in a double-compartment model gave reproducible information.


CONCLUSIONS
The usefulness of this mini-invasive technique for sequential measurements before and during intervention will render the 133Xe clearance suitable for assessment of blood flow changes in the abdominal cavity.
Oman
M
M
Department of Surgical and Perioperative Science, Surgery, Umeå University Hospital, Umeå, Sweden. mikael.oman@surgery.umu.se
Tölli
J
J
Blind
P J
PJ
Naredi
P
P
Hafström
L O
LO
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D015902:Gamma Cameras; D017078:Laser-Doppler Flowmetry; D008833:Microcirculation / Q000187:drug effects; D010537:Peritoneum / Q000098:blood supply* / Q000000981:diagnostic imaging; D011859:Radiography; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014667:Vasopressins / Q000494:pharmacology*; D014980:Xenon Radioisotopes / Q000493:pharmacokinetics*
D014662:Vasoconstrictor Agents; D014980:Xenon Radioisotopes; D014667:Vasopressins