Procedure—Dogs were anesthetized with glycopyrrolate,
morphine, propofol, and isoflurane. Thirteen
dogs were treated with ketamine IV, as follows: 0.5
mg/kg (0.23 mg/lb) as a bolus before surgery, 10
µg/kg/min (4.5 µg/lb/min) during surgery, and 2
µg/kg/min (0.9 µg/lb/min) for 18 hours after surgery.
Fourteen dogs received the same volume of saline
(0.9% NaCl) solution. All dogs received an infusion of
fentanyl (1 to 5 µg/kg/h [0.45 to 2.27 µg/lb/h]) for the
first 18 hours after surgery. Dogs were evaluated for
signs of pain before surgery, at the time of extubation,
and 1, 2, 3, 4, 12, and 18 hours after extubation.
Owners evaluated their dogs' appetite, activity, and
wound soreness on postoperative days 2, 3, and 4.
Results—Dogs that received ketamine infusions had
significantly lower pain scores 12 and 18 hours after
surgery and were significantly more active on postoperative
day 3 than dogs that received saline solution
Conclusions and Clinical Relevance—Results suggest
that perioperative administration of low doses of
ketamine to dogs may augment analgesia and comfort
in the postoperative surgical period. (J Am Vet
Med Assoc 2002;221:72–75)
OBJECTIVE To determine brain region affinity for and retention of gadolinium in dogs after administration of gadodiamide and whether formalin fixation affects quantification.
ANIMALS 14 healthy dogs.
PROCEDURES 13 dogs received gadodiamide (range, 0.006 to 0.1 mmol/kg, IV); 1 control dog received a placebo. Dogs received gadodiamide 3 to 7 days (n = 8) or 9 hours (5) before euthanasia and sample collection. Brain regions were analyzed with inductively coupled mass spectrometry (ICP-MS) and transmission electron microscopy. Associations between dose, time to euthanasia, and gadolinium retention quantities (before and after fixation in 5 dogs) were evaluated.
RESULTS Gadolinium retention was seen in all brain regions at all doses, except for the control dog. Exposure 3 to 7 days before euthanasia resulted in 1.7 to 162.5 ng of gadolinium/g of brain tissue (dose-dependent effect), with cerebellum, parietal lobe, and brainstem affinity. Exposure 9 hours before euthanasia resulted in 67.3 to 1,216.4 ng of gadolinium/g of brain tissue without dose dependency. Transmission electron microscopy revealed gadolinium in examined tissues. Fixation did not affect quantification in samples immersed for up to 69 days.
CONCLUSIONS AND CLINICAL RELEVANCE Gadodiamide exposure resulted in gadolinium retention in the brain of healthy dogs. Cerebellum, parietal lobe, and brainstem affinity was detected with dose dependency only in dogs exposed 3 to 7 days before euthanasia. Fixation had no effect on quantification when tissues were immersed for up to 69 days. Physiologic mechanisms for gadolinium retention remained unclear. The importance of gadolinium retention requires further investigation.