Objective—To evaluate the safety and efficacy of thoracoscopically
guided pulmonary wedge resection in
Animals—10 horses (5 control horses and 5 horses
affected with recurrent airway obstruction [ie,
Procedure—Each horse underwent a thoracoscopically
guided pulmonary wedge resection. Before, during,
and after surgery, heart rate, respiratory rate,
arterial blood gases, and systemic and pulmonary
arterial pressures were measured. Physical examination,
CBC, and thoracic radiography and ultrasonography
were performed 24 hours before and 2 and 48
hours after surgery. Pulmonary specimens were
assessed by histologic examination. A second thoracoscopic
procedure 14 days later was used to evaluate
the resection site.
Results—The technique provided excellent specimens
for histologic evaluation of the lung. Heart and
respiratory rates decreased significantly after horses
were administered sedatives. A significant transient
decrease in PaO2 was detected immediately after pulmonary
wedge resection, but we did not detect significant
effects on arterial pH, Paco2, or mean arterial
and pulmonary arterial pressures. All horses except 1
were clinically normal after thoracoscopic surgery;
that horse developed hemothorax attributable to iatrogenic
injury to the diaphragm. The second thoracoscopy
revealed minimal inflammation, and there
were no adhesions.
Conclusion and Clinical Relevance—Thoracoscopically
guided pulmonary wedge resection provides
a minimally invasive method for use in obtaining specimens
of lung tissues from healthy horses and those
with lung disease. This technique may be useful for the
diagnosis of diseases of the lungs and thoracic cavity.
(Am J Vet Res 2002;63:1232–1240)
Objective—To evaluate the pharmacokinetic-pharmacodynamic parameters of enrofloxacin and a low dose of amikacin administered via regional IV limb perfusion (RILP) in standing horses.
Animals—14 adult horses.
Procedures—Standing horses (7 horses/group) received either enrofloxacin (1.5 mg/kg) or amikacin (250 mg) via RILP (involving tourniquet application) in 1 forelimb. Samples of interstitial fluid (collected via implanted capillary ultrafiltration devices) from the bone marrow (BMIF) of the third metacarpal bone and overlying subcutaneous tissues (STIF), blood, and synovial fluid of the radiocarpal joint were collected prior to (time 0) and at intervals after tourniquet release for determination of drug concentrations. For pharmacokinetic-pharmacodynamic analyses, minimum inhibitory concentrations (MICs) of 16 μg/mL (amikacin) and 0.5 μg/mL (enrofloxacin) were applied.
Results—After RILP with enrofloxacin, 3 horses developed vasculitis. The highest synovial fluid concentrations of enrofloxacin and amikacin were detected at time 0; median values (range) were 13.22 μg/mL (0.254 to 167.9 μg/mL) and 26.2 μg/mL (5.78 to 50.0 μg/mL), respectively. Enrofloxacin concentrations exceeded MIC for approximately 24 hours in STIF and synovial fluid and for 36 hours in BMIF. After perfusion of amikacin, concentrations greater than the MIC were not detected in any samples. Effective therapeutic concentrations of enrofloxacin were attained in all samples.
Conclusions and Clinical Relevance—In horses with orthopedic infections, RILP of enrofloxacin (1.5 mg/kg) should be considered as a treatment option. However, care must be taken during administration. A dose of amikacin > 250 mg is recommended to attain effective tissue concentrations via RILP in standing horses.