The Tourniquet in Surgery A Review

Intraosseous Gentamicin Perfusion of the Distal Metacarpus in Standing Horses

OBJECTIVE

To report tissue gentamicin concentrations after intraosseous (IO) perfusion in standing horses.

STUDY DESIGN

In vivo study.

ANIMALS OR SAMPLE POPULATION

Twelve horses.

METHODS

Sedated horses had a cannulated cortical bone screw inserted into the dorsolateral aspect of the treated metacarpus and a tourniquet applied proximally. Gentamicin (2.2 mg/kg) diluted in sterile saline solution (0.1 mL/kg) was infused through the screw. Two horses were euthanatized at each time interval: 0, 2, 6, 12, 24, and 36 hours. Synovial fluid and bone samples were collected distal to the screw from both forelimbs. Gentamicin concentrations were measured using fluorescence polarization immunoassay.

RESULTS

The highest synovial fluid gentamicin concentrations were 385+/-273 microg/mL (mean+/-SD) in the metacarpophalangeal joint, 225+/-205 microg/mL in the proximal interphalangeal joint, 215+/-205 microg/mL in the distal interphalangeal joint, 382+/-195 microg/mL in the digital flexor tendon sheath, and 206+/-161 microg/mL in the navicular bursa. The highest bone concentrations of gentamicin were 55+/-30 microg/g in the distal metacarpus, 34+/-27 microg/g in the proximal, 16+/-15 microg/g in the middle, and 16+/-2.2 microg/g in the distal phalanges, and 27+/-17 microg/g in the proximal and 24+/-11 microg/g in the distal sesamoid bones.

CONCLUSION

Standing IO perfusion of gentamicin resulted in local antibiotic concentrations in the synovial structures and bones of the distal aspect of the limb that exceed the reported minimum inhibitory concentration of pathogens commonly implicated in equine orthopedic infections.

CLINICAL RELEVANCE

Standing IO perfusion of gentamicin in the distal aspect of the limb should be considered for treatment of orthopedic infections of this region in horses.

Ischemic bandage injuries: a case series and review of the literature

OBJECTIVE

To determine the prognosis and distribution of ischemic injuries caused by inappropriate bandaging of the lower limb in dogs and cats.

STUDY DESIGN

Retrospective clinical study.

ANIMAL POPULATION

Eleven client-owned animals, including 9 dogs and 2 cats with a history of injuries consistent with incorrect application of a bandage.

METHODS

Medical records for dogs and cats referred to the Queen's Veterinary School Hospital with limb wounds between 1995 and 1999 were reviewed for clinical history and referring veterinary surgeons' reports, indicating that the injury was directly related to the application of a bandage to the limb.

RESULTS

The indications for bandage application included 2 postoperative cruciate ligament ruptures, 2 lacerations, 3 internal fixations, an onychectomy, a shoulder dislocation, a dog bite, and a tendon strain. None of the patients had other body systems involved or underlying or concurrent diseases. Five different types of bandage were described (support, Robert Jones, pressure, splint, and Velpeau), and no particular age or breed was overrepresented. Of the 11 animals, 5 required full-thickness skin grafts, 3 had to have digits amputated, and 2 required limb amputations. Nine animals survived, but only 4 became fully functional on the affected limb.

CONCLUSIONS

Bandage-related injuries are potentially serious sequelae to a routine procedure. A guarded prognosis should be given when there is loss of deeper structures.

CLINICAL RELEVANCE

A review of bandaging principles is presented. Method of application, choice of materials, and close monitoring of the bandage are important factors in preventing iatrogenic injury.

Single-dose pharmacokinetics of cefazolin in bovine synovial fluid after intravenous regional injection

The pharmacokinetic properties of cefazolin in the synovial fluid of the tibiotarsal joint were determined in 10 healthy mature cattle after intravenous regional injections of 250 mg cefazolin. A pneumatic tourniquet was positioned proximal to the tibiotarsal joint and the intravenous injection was performed distal to the tourniquet. Synovial fluid concentrations of cefazolin increased in the first 30 min and fluctuated between 54.7 +/- 11.0 micrograms/ml (mean +/- SEM) and 73.2 +/- 13.2 micrograms/ml in the following 90 min while the tourniquet remained inflated. After tourniquet removal, synovial fluid concentration-time curves followed first-order one-compartment model decay in most of the animals with an elimination half-life of 0.82 h (harmonic mean). Therapeutic concentrations of cefazolin in the synovial fluid of normal joints were reached and this injection technique could be used as an alternative to systemic administration of antibiotics to provide adequate concentrations in a localized area.