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OBJECTIVE To determine whether the position or elevation of charcoal air-filtration canisters would impact efficacy of waste anesthetic gas (WAG) scavenging.

DESIGN Randomized experiment.

SAMPLE 2 types of bottom-vented and 1 type of top-vented charcoal air-filtration canisters (n = 8 of each canister type/evaluation session).

PROCEDURES Canisters were evaluated in a vertical or horizontal position at both low and high isoflurane gas flow rates in a modified Bain nonrebreathing circuit. Waste anesthetic gas concentrations were measured 2.54 cm from canister exhaust ports with an ambient air analyzer every 30 seconds for a maximum of 15 min/experimental condition. One type of bottom-vented canister was tested in a vertical position elevated above or suspended below the vaporizer at a high isoflurane flow rate and then a standard maintenance flow rate.

RESULTS Position had no significant effect on WAG emission by any canister type at low isoflurane flow rates. Horizontally positioned bottom-vented canisters at the high isoflurane flow rate emitted significantly more WAG than vertically positioned canisters. Horizontally positioned top-vented canisters at high flow rates emitted significantly more WAG than vertically positioned canisters at the final 15-minute time point only. Cannister types differed significantly in intercanister variability. Canister elevation relative to the vaporizer had no impact on WAG scavenging efficacy.

CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that charcoal air-filtration canisters should be used in a vertical position when anesthetizing animals with the anesthetic delivery system used in this study.

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in Journal of the American Veterinary Medical Association


Objective—To develop a method for percutaneous collection of fetal fluid from cattle in the late stages of gestation and determine whether bovine viral diarrhea virus (BVDV) can be isolated from such fluids.

Design—Case series.

Animals—169 pregnant beef cattle.

Procedure—Animals were restrained in a squeeze chute, and hair was clipped from a region of the right flank. Pregnancy was confirmed, and fetal fluids were identified by means of abdominal ultrasonography. Fetal fluid was collected with a spinal needle. Virus isolation was performed on fetal fluids, WBC lysates from 160 live calves, and tissues from 12 calves that died or were aborted. Blood samples collected from adult cattle were assayed with an immunoperoxidase monolayer assay.

Results—Fourteen animals aborted or delivered premature calves within 3 weeks after fetal fluid collection; however, it could not be determined whether this was a complication of the procedure or attributable to other factors. Results of BVDV isolation from fetal fluid samples were negative for 168 animals. However, a noncytopathic BVDV was isolated from fetal fluid obtained from a 2-year-old heifer; results of the immunoperoxidase assay of serum from this heifer were also positive, and a noncytopathic BVDV was isolated from tissue specimens from a stillborn calf produced by this heifer.

Conclusions and Clinical Relevance—Results suggest that fetal fluids can be collected percutaneously from cattle in the late stages of gestation and that virus isolation performed on fetal fluids can be used to identify fetuses infected with BVDV in utero. However, safety of the procedure could not be evaluated. (J Am Vet Med Assoc 2002;220:1348–1352).

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in Journal of the American Veterinary Medical Association