Fluid Therapy for Pediatric Patients.

Pediatric dogs and cats within their first 12 weeks of life have important electrolyte requirements and physiologic considerations that may impact fluid therapy. Fluid requirements are higher in pediatrics, while fluid losses are greater due to underdeveloped physiologic responses. Hydration and volume status are difficult to assess in young animals, and their small size makes intravenous (IV) access difficult to obtain. Young patients can quickly deteriorate from dehydration, poor husbandry, and infection and become critically ill, requiring prompt recognition, treatment, intensive care, and monitoring. Clinicians should be aware of all available routes of fluid administration including oral, subcutaneous (SC), intraperitoneal (IP), IV, and intraosseous (IO), and the limitations associated with each route.

Comparison of 3 intraosseous catheter sites and methods of determining placement success in cadaver rabbits.

The study goals were to determine if intraosseous (IO) catheters can be placed with greater success into the humerus, femur, or tibia of cadaver rabbits, and to evaluate the accuracy of perceived success (PS) and objective clinical success (OCS) criteria against true intramedullary catheterization confirmed by fluoroscopy. This was a prospective study utilizing 12 rabbit cadavers. Twenty-two participants attempted IO catheter placement at 3 sites. Perceived success, OCS, and fluoroscopic true success (FTS) were recorded. A Fisher's exact test was used to compare PS, OCS, and FTS, and FTS rates between sites (P < 0.05). A Wilcoxon test was used to compare speed of placement (P < 0.05). Overall, of 66 attempts, PS was reported in 86.4%, OCS was documented in 62.1%, FTS was confirmed in 43.9%. Perceived success and OCS overestimated FTS (P ≤ 0.01 and P = 0.027, respectively). Confirmation of FTS occurred in 10/22 (45.5%) humeral, 5/22 (22.7%) femoral, and 14/22 (63.6%) tibial (P = 0.03) attempts. Median time until placement for the humerus was 37.5 seconds (range: 15 to 125 seconds); the femur 135 seconds (range: 91 to 148 seconds); the tibia 49 seconds (range: 19 to 150 seconds). The humerus and tibia were faster to catheterize than the femur (P = 0.01 and 0.03, respectively). Participant PS and OCS criteria overestimated FTS. The humerus or tibia may be more successful and are faster to catheterize.

Les objectifs de la présente étude étaient de déterminer si des cathéters intra-osseux (IO) peuvent être placés avec plus de succès dans l'humérus, le fémur ou le tibia de cadavres de lapins, et d'évaluer la précision des critères du succès perçu (PS) et du succès clinique objectif (OCS) versus le cathétérisme intramédullaire réel confirmé par fluoroscopie. Il s'agissait d'une étude prospective utilisant 12 cadavres de lapin. Vingt-deux participants ont tenté le placement des cathéters IO aux trois sites. Le PS, l'OCS et le succès réel par fluoroscopie (FTS) furent notés. Un test exact de Fisher fut utilisé pour comparer PS, OCS, et FTS, et les taux de FTS entre les sites (P < 0,05). Un test de Wilcoxon a été utilisé pour comparer la vitesse de placement (P < 0,05). Globalement, des 66 essais, PS a été rapporté dans 86,4 % des cas, OCS a été documenté dans 62,1 % des cas, et FTS a été confirmé dans 43,9 % des cas. Le PS et l'OCS surestimaient le FTS (P ≤ 0,01 et P = 0,027, respectivement). La confirmation de FTS s'est produite dans 10/22 (45,5 %) des essais sur l'humérus, 5/22 (22,7 %) des essais sur le fémur, et 14/22 (63,6 %) des essais sur le tibia (P = 0,03).Le temps médian du placement pour l'humérus était de 37,5 secondes (écart : 15 à 125 secondes); pour le fémur de 135 secondes (écart : 91 à 148 secondes); et pour le tibia de 49 secondes (écart : 19 à 150 secondes). Le cathétérisme de l'humérus et du tibia étaient plus rapides que celui du fémur (P = 0,01 et 0,03, respectivement). Les critères pour le PS et l'OCS des participants surestimaient le FTS. L'humérus et le tibia sont plus rapides à cathétériser et le taux de succès est meilleur.(Traduit par Docteur Serge Messier).

Comparison of time to obtain intraosseous versus jugular venous catheterization on canine cadavers.

OBJECTIVE: To compare the time required and the success rate of personnel with 4 different levels of experience to place a humeral intraosseous (IO) catheter versus a jugular venous catheter (IV) in cadaver dogs. DESIGN: Prospective study. SETTING: Veterinary university teaching hospital. INTERVENTIONS: Canine cadavers from recently euthanized dogs were obtained from the cadaver donation program between May and December 2014. Catheter placers (CPs) with varying clinical experience, including a first year emergency and critical care resident, a senior emergency veterinary technician (VTS certified), a final year veterinary student, and an ACVECC diplomate, participated in the study. Each CP catheterized a total of 6 dogs so that there was a total of 6 IO and 6 IV catheters placed, by automatic rotary insertion device (with an EZ-IO gun) and vascular cut-down technique, respectively, for each CP. Time for IO catheterization and IV catheterization was recorded and compared. The success of IO catheterization and IV catheterization was verified by visualization of an injection of iodinated contrast material under fluoroscopy within the medullary cavity or vessel. ANIMALS: Twenty-four canine cadavers. MEASUREMENTS AND MAIN RESULTS: Outcomes were analyzed using the Wilcoxon rank-sum test and the Kruskal-Wallis one-way analysis of variance. The median time for all IO catheterization operators was faster at 55.4 seconds (range 15.0-153.0 s) compared to the median time for all IV catherization operators at 217.3 seconds (range 55.6-614 s). The success rate for IO and IV was equal at 87.5%. CONCLUSION: IO catheterization using an automatic rotary insertion device was performed more rapidly and successfully than jugular venous catheterization using a cut-down technique in canine cadaver. These findings suggest IO catheterization may be more efficient for gaining vascular access in the appropriate emergency clinical situations when preexisting IV access does not exist.

Alternative Access Routes for Fluid Resuscitation.

Fluid resuscitation in small animals is important in emergency situations and is utilized by every veterinary practice. Peripherally inserted intravenous catheters are an effective way of giving fluids to a veterinary patient. If an intravenous catheter is not obtainable, there are multiple other ways to administer fluids to a patient including dorsal pedal catheters, intraosseous catheters, central venous catheters, peripherally inserted central catheters, nasogastric tubes, nasoesophageal tubes and subcutaneous administration of fluids. This article will discuss the advantages and disadvantages of each way of administration.

Intraosseous infusion of the distal phalanx compared to systemic intravenous infusion for marimastat delivery to equine lamellar tissue.

No validated laminitis drug therapy exists, yet pharmaceutical agents with potential for laminitis prevention have been identified. Many of these are impractical for systemic administration but may be effective if administered locally. This study compared intraosseous infusion of the distal phalanx (IOIDP) with systemic intravenous constant rate infusion (CRI) to determine which was more effective for lamellar marimastat delivery. Ultrafiltration probes were placed in both forefeet of five horses to collect lamellar interstitial fluid as lamellar ultrafiltrate (LUF). Marimastat solution (3.5 mg/mL) containing lidocaine (20 mg/mL) was infused by IOIDP at 0.15 mL/min for 12 h. After a 12 h wash-out, marimastat (3.5 mg/mL) and lidocaine were infused by constant rate infusion (CRI) at 0.15 mL/min for 12 h. LUF, plasma and lamellar tissue marimastat concentrations were quantified using UPLC-MS. Zymography was used to establish the inhibitory concentrations of marimastat for equine lamellar matrix metalloproteinases (MMPs). Data were analysed non-parametrically. There was no difference between the steady-state marimastat concentration in lamellar ultrafiltrate (LUF[M]) during IOIDP (139[88-497] ng/mL) and CRI (136[93-157] ng/mL). During IOIDP, there was no difference between marimastat concentrations in the treated foot (139[88-497] ng/mL), the untreated foot (91[63-154] ng/mL) and plasma (101[93-118] ng/mL). LUF[M] after IOIDP and CRI were >IC50 of lamellar MMP-2 and 9, but below the concentration considered necessary for in vivo laminitis prevention. Lamellar drug delivery during IOIDP was inconsistent and did not achieve higher lamellar marimastat concentrations than CRI. Modification or refinement of the IOIDP technique is necessary if it is to be consistently effective.

Pharmacokinetics and pharmacodynamics of xylazine administered by the intravenous or intra-osseous route in adult horses.

In certain situations, an alternate route for parenteral drug administration in horses may be useful. The intra-osseous (IO) route may provide a safe alternative to the intravenous (i.v.) route for administration of sedatives to horses when the i.v. route is inaccessible or undesirable. Six adult horses were administered xylazine i.v. or IO in a block-randomized crossover design. For the i.v. trial, both jugular veins were catheterized, and one was used for xylazine administration, while the other was used for blood collection. For the IO trial, one jugular vein was catheterized for blood collection and an intra-osseous device was placed in the tuber coxae using a powered driver for xylazine administration. Heart rate, respiratory rate, and head position were measured, and concentration of sedation was assessed at various times up to 90 min. Xylazine concentrations were measured using high-performance liquid chromatography and noncompartmental analysis was performed. General linear mixed modeling and Wilcoxon signed-rank tests were used for statistical analysis, with P ≤ 0.05. There were no significant differences in heart rate, respiratory rate, head position, concentration of sedation, Cmax , Tmax , half-life, or AUC between the i.v. and the IO routes of drug administration. No complications were observed following placement of the intra-osseous device. Intra-osseous xylazine administration provides a useful option in emergent and other settings in which i.v. access is difficult or contraindicated.

Comparison of time to loss of consciousness and maintenance of anesthesia following intraosseous and intravenous administration of propofol in rabbits.

OBJECTIVE: To compare time to loss of consciousness (LOC) and effective maintenance of anesthesia following intraosseous (IO) and IV administration of propofol in rabbits. DESIGN: Evaluation study. ANIMALS: 24 New Zealand White rabbits. PROCEDURES: Rabbits were selected to receive IO (n = 6) or IV (6) bolus administration of 1% propofol (12.5 mg/kg [5.67 mg/lb]) only or an identical bolus of propofol IO (6) or IV (6) followed by a constant rate infusion (CRI; 1 mg/kg/min [0.45 mg/lb/min]) by the same route for 30 minutes. Physiologic variables were monitored at predetermined time points; time to LOC and durations of anesthesia and recovery were recorded. RESULTS: Following IO and IV bolus administration, mean time to LOC was 11.50 and 7.83 seconds, respectively; changes in heart rate, respiratory rate, oxygen saturation (as measured by pulse oximetry), and mean arterial blood pressure values were evident, but findings did not differ between groups. For the IO- and IV-CRI groups, propofol-associated changes in heart rate, oxygen saturation, and mean arterial blood pressure values were similar, and although mean arterial blood pressure decreased significantly from baseline, values remained > 60 mm Hg; respiratory rate decreased significantly during CRI in both groups, but remained higher in the IO-CRI group. Anesthesia and recovery time did not differ between the IO- and IV-CRI groups. CONCLUSIONS AND CLINICAL RELEVANCE: In all evaluated aspects of anesthesia, IO administration of propofol was as effective as IV administration in rabbits. Results suggested that total IO anesthesia can be performed in rabbits with limited vascular access.

Comparison of three intraosseous access techniques in cats.

OBJECTIVE: To compare the placement feasibility and amount of bone trauma induced by 3 intraosseous (IO) access techniques in cats: an automatic impact penetration device (A), an automatic rotary insertion device (B), and a manual IO needle (C). DESIGN: Prospective ex vivo study. SETTING: University. ANIMALS: Eighteen adult mixed breed feline cadavers. INTERVENTIONS: Cadavers provided 72 total IO insertion locations divided equally between the right and left humerus and tibia. The 3 IO techniques were randomly allocated to these locations. Time to successful insertion, ease of insertion, and success rate were recorded. Each insertion site was analyzed for the number of bone fragments and defect diameter by computed tomography. MEASUREMENTS AND MAIN RESULTS: Device B had lower time of insertion (P=0.01) compared with devices A and C. Device B had better ease of insertion scores (P<0.01) compared with devices A and C. No differences were detected between insertion sites (tibia versus humerus). No differences in the number of bone fragments, defect diameter, or success rate were detected among devices (P=0.06, 0.31, and 0.14, respectively). CONCLUSIONS: All 3 IO access methods evaluated yield acceptable results. Device B is significantly faster and easier to place in cat cadavers when compared with other methods.

Osteomyelitis and osteonecrosis after intraosseous perfusion with gentamicin.

OBJECTIVE: To describe and discuss previously unreported complications associated with intraosseous perfusion with gentamicin in horses. STUDY DESIGN: Case report. ANIMALS: Ten-year-old Warmblood gelding. METHODS: Intraosseous perfusion with gentamicin into the proximal phalanx (P1) was used as part of the treatment regimen for distal interphalangeal joint and navicular bursa synovial sepsis. Although the sepsis responded favorably complications developed at the perfusion site, including persistent osteomyelitis, progressive osteonecrosis, and ultimately pathologic fracture of P1. RESULTS: The progression of the clinical signs and findings at necropsy are suggestive of a toxic osteonecrosis secondary to intraosseous perfusion. CONCLUSIONS: Further work is needed to investigate the effects of high dose gentamicin on equine mesenchymal cells that may be achieved during intraosseous perfusion. CLINICAL RELEVANCE: Lower doses of perfusate within the medullary canal of P1 or alternative perfusion sites should be considered.

Development of intraosseous infusion of the distal phalanx to access the foot lamellar circulation in the standing, conscious horse.

Intraosseous (i.o.) infusion of the distal phalanx (IOIDP) as a delivery route targeting hoof lamellar tissue of standing, conscious horses was evaluated. Following sedation and regional nerve blockade in six Standardbred horses, a microdialysis (MD) probe was implanted into the hoof lamellar tissue of one forelimb. A purpose designed cannulated bone screw was introduced into the body of the distal phalanx, approximately 6 cm from the MD probe. Gentamicin solution (25 mg/mL) was infused at 20 microL/min through the bone screw for 2 h without the application of a tourniquet. MD and blood samples were collected at regular intervals and analysed for gentamicin concentrations. Gentamicin was present in lamellar tissue at much higher concentrations than peripheral serum. The mean concentration of gentamicin was 24.4, 20.5 and 4.4 microg/mL in extracellular fluid (ECF) and 0.28, 0.5 and 0.32 microg/mL in serum samples collected 60, 120 and 150 min after IOIDP was started, respectively. A clinically safe and efficacious i.o. drug delivery to the hoof lamellar tissue of standing, conscious horse was developed.

Intraosseous catheter placement in small mammals.

Intraosseous catheterization may be used to administer fluids or medications to small mammals, particularly when intravenous access cannot be established. This column describes the necessary equipment, procedure and potential complications of intraosseous catheterization.

Comparison of two indirect techniques for local delivery of a high dose of an antimicrobial in the distal portion of forelimbs of horses.

OBJECTIVE: To compare isolated limb retrograde venous injection (ILRVI) and isolated limb infusion (ILI) for delivery of amikacin to the synovial fluid of the distal interphalangeal and metacarpophalangeal joints and to evaluate the efficacy of use of an Esmarch tourniquet in standing horses. ANIMALS: 6 healthy adult horses. PROCEDURES: Horses were randomly assigned in a crossover design. In ILRVI, the injection consisted of 1 g of amikacin diluted to a total volume of 60 mL administered during a 3-minute period. In ILI, the infusion consisted of 1 g of amikacin diluted to 40 mL administered during a 3-minute period followed by administration of boluses of diluent (82 mL total) to maintain vascular pressure. During ILI, the infusate and blood were circulated from the venous to the arterial circulation in 5-mL aliquots. Synovial fluid and serum samples were obtained to determine maximum amikacin concentrations and tourniquet leakage, respectively. RESULTS: Both techniques yielded synovial concentrations of amikacin > 10 times the minimum inhibitory concentration (MIC) for 90% of isolates (80 microg/mL) and > 10 times the MIC breakpoint (160 microg/mL) of amikacin-susceptible bacteria reported to cause septic arthritis in horses. These values were attained for both joints for both techniques. Esmarch tourniquets prevented detectable loss of amikacin to the systemic circulation for both techniques. CONCLUSIONS AND CLINICAL RELEVANCE: Both techniques reliably achieved synovial fluid concentrations of amikacin consistent with concentration-dependent killing for bacteria commonly encountered in horses with septic arthritis. Esmarch tourniquets were effective for both delivery techniques in standing horses.

Comparison of intraosseous and intramuscular drug administration for induction of anaesthesia in domestic pigeons.

The aim of the present study was to assess the feasibility of intraosseous anaesthetic drug administration in domestic pigeons and to compare this method with an intramuscular technique for clinical parameters (induction quality and recovery of anaesthesia), heart-respiratory rate and cloacal temperature. Sixteen clinically healthy mature pigeons (7 male and 9 female) were included into the study. The birds were allocated into two groups as group I and II. Pigeons in group I received 50mg/kg ketamine by intraosseous route (IO) and birds in group II received intramuscular (IM) ketamine application at a dose of 50mg/kg. Heart rate (HR), respiratory rate (RR) and cloacal temperature (CT) were measured before (0 min) and 1, 3, 5, 10, 15, 20 and 30 min after anaesthetic drug administration. Clinical and anaesthetic effect of the ketamine used in different route were assessed. Statistical assessment performed between the groups revealed that RR in IM group was higher than in IO group between 1 and 3 min (p<0.001 and p<0.01, respectively), whereas in 15 min it was higher in IO group than IM (p<0.01) (Fig. 1A). Compared to baseline values, there was a decrease for HR within 3 to 15 min for both groups. However, this was statistically different between 5, 10 and 15 min for IM group. No significant alterations were recorded for CT during the anaesthesia for both groups. The anaesthetic effect of the ketamine started 1 to 3 min (1.8+/-0.4) after injection for Group I and 5 to 10 min (7.5+/-0.8) for Group II. The recovery time ranged from 50 to 75 min (62+/-15) for Group I and 80 to 100 min (90+/-12) for the Group II. Intraosseous and intramuscular ketamine administration resulted in a satisfactory anaesthesia in pigeons. However, intraosseous drug administration provided a more rapid and effective anaesthesia and might be useful for the birds requiring urgent anaesthesia.

The pharmacokinetic behaviour of marbofloxacin in Eurasian buzzards (Buteo buteo) after intraosseous administration.

This study reports on the administration of a single dose of marbofloxacin (2 mg/kg) to five adult Eurasian buzzards (Buteo buteo) by the intraosseous (IO) route, which has been proposed as a rapid and efficient means for the parenteral delivery of antimicrobial drugs. The drug was rapidly absorbed. Peak marbofloxacin concentration (C(max)) in plasma and area under the concentration-time curve (AUC) of 1.92+/-0.78 microg/mL and 8.53+/-2.73 microg h/mL, respectively. The time marbofloxacin remained in the plasma after IO administration was relatively short (elimination half-life, t(1/2beta)=4.91+/-0.65 h; mean residence time (MRT)=5.38+/-0.57 h). Single dose marbofloxacin gave values for C(max)/minimum inhibitory concentration (MIC) of 19.2 and an AUC/MIC value of 85.3h after IO administration. The IO route appears to be practical and effective for the rapid delivery of marbofloxacin to buzzards.

Antimicrobial regional limb perfusion in horses.

Regional limb perfusion involves administration of an antimicrobial solution into the vasculature of a selected portion of the limb that has been isolated from the systemic circulation by controlled application of a tourniquet. The technique provides high antimicrobial concentrations in the region of interest and greatly contributes to the elimination of infection.

Medullary plasma pharmacokinetics of vancomycin after intravenous and intraosseous perfusion of the proximal phalanx in horses.

OBJECTIVE: To study the pharmacokinetics of vancomycin in plasma obtained from the medullary sinusoids of the proximal phalanx (P1) after intravenous (IV) and intraosseous (IO) regional limb perfusion (RLP). STUDY DESIGN: Experimental study. ANIMALS: Twelve horses. METHODS: IV and IO RLP were performed in 2 groups (n = 6) of horses. Vancomycin hydrochloride (300 mg in 60 mL 0.9% NaCl) was randomly infused in 1 front limb, with the contralateral limb as control (60 mL 0.9% NaCl). A hole was drilled in the lateral cortex of P1, and blood samples from the medullary sinusoids of P1 were collected before infusion, and 15, 30, 45, 65, and 90 minutes after beginning infusion. Samples were centrifuged and plasma vancomycin concentrations determined. Vancomycin concentrations were compared over time and between routes using a 2-way repeated measures ANOVA. Pharmacokinetic variables were compared with a Kolmogorov-Smirnov test. Significance was set at P<.05. RESULTS: No vancomycin-induced clinical side effects such as lameness or swelling were observed. Both techniques, IV and IO, produced high vancomycin concentrations in the sinusoidal plasma of the P1, which remained above the minimum inhibitory concentration value for methicillin-resistant Staphylococcus aureus (MRSA) during the 90 minutes study. Concentrations and pharmacokinetic variables were not significantly different comparing both routes. CONCLUSIONS: IV and IO routes produced similar antimicrobial perfusion of the medullary cavity of P1. CLINICAL RELEVANCE: Either IV or IO routes for perfusion are likely to be equally selected when planning RLP with vancomycin.

Comparison of intraosseous and intravenous infusion of technetium Tc 99m pertechnate in the distal portion of forelimbs in standing horses by use of scintigraphic imaging.

OBJECTIVE: To describe and compare the distribution of technetium Tc 99m (99mTc) pertechnate following intraosseous or i.v. injection (with or without use of a tourniquet) in the distal portion of the forelimb in standing horses. ANIMALS: 4 horses. PROCEDURE: Each horse received 4 forelimb treatments in random sequence: intraosseous infusion with tourniquet application (IOT), intraosseous infusion without tourniquet application, i.v infusion with tourniquet application (IVT), and i.v. infusion without tourniquet application. Dynamic nuclear scintigraphic imaging of the third metacarpal bone, proximal and middle phalanges, and distal phalanx was performed from the start of each treatment until 1 hour after infusion was completed. Radionuclide activity was compared within and between treatment groups. RESULTS: Tourniquet application was necessary to maintain high levels of radionuclide activity in the distal portion of the forelimb after intraosseous or i.v. infusion with 99mTc pertechnate; IVT and IOT treatments resulted in similar radionuclide activity in the proximal and middle phalanges and distal phalanx. Of the 4 treatments, there was significantly higher radionuclide activity in the distal aspect of the third metacarpal bone after the IOT treatment. CONCLUSIONS AND CLINICAL RELEVANCE: By use of a tourniquet, radionuclide administration via the intraosseous or i.v. routes resulted in effective perfusion of the distal portion of the forelimb and similar distribution of the agent in the phalanges of horses. Further studies are required to ascertain whether these findings apply to delivery of therapeutic agents in infected tissues via IOT or IVT.

Carboplatin pharmacokinetics following a single-dose infusion in sulphur-crested cockatoos (Cacatua galerita).

OBJECTIVE: To determine the pharmacokinetics of carboplatin in sulphur-crested cockatoos, so that its use in clinical studies in birds can be considered. DESIGN: A pharmacokinetic study of carboplatin, following a single intravenous (IV) or intraosseus (IO) infusion over 3 min, was performed in six healthy sulphur-crested cockatoos (Cacatua galerita). PROCEDURE: Birds were anaesthetised and a jugular vein cannulated for blood collection. Carboplatin (5 mg/kg) was infused over 3 min by the IV route in four birds via the contralateral jugular vein, and by the IO route in two birds via the ulna. Serial blood samples were collected for 96 h after initiation of the infusion. Tissue samples from 11 organs were obtained at necropsy, 96 h after carboplatin administration. Total Pt and filterable Pt in plasma and tissue Pt concentrations were assayed by inductively coupled plasma-mass spectrometry. A noncompartmental pharmacokinetic analysis was performed on the plasma data. RESULTS: The mean +/- SD for the Cmax of filterable Pt was 27.3 +/- 4.06 mg/L and in all six birds occurred at the end of the 3 min infusion, thenceforth declining exponentially over the next 6 h to an average concentration of 0.128 +/- 0.065 mg/L. The terminal half-life (T1/2) was 1.0 +/- 0.17 h, the systemic clearance (CI) was 5.50 +/- 1.06 mL/min/kg and the volume of distribution (Vss) was 0.378 +/- 0.073 L/kg. The extrapolated area under the curve (AUC0-x) was 0.903 +/- 0.127 mg/mL x min; the area extrapolated past the last (6 h) data point to infinite time averaged only 1.25% of the total AUC0-x. The kidneys had the greatest accumulation of Pt (7.04 +/- 3.006 microg/g), followed by the liver (3.08 +/- 1.785 microg/g DM). CONCLUSIONS AND CLINICAL RELEVANCE: Carboplatin infusion in sulphur-crested cockatoos produced mild, transient alimentary tract signs and the Pt plasma concentration was similar whether carboplatin was given intravenously or intraosseously. Filterable plasma Pt concentrations for carboplatin persisted longer than for cisplatin, due mostly to the difference in systemic clearance between these drugs in sulphur-crested cockatoos. The distribution of tissue Pt after carboplatin administration was similar to that reported for cisplatin in sulphur-crested cockatoos. Despite anatomical, physiological and biochemical differences among animal species, the pharmacokinetic disposition of filterable Pt in the sulphur-crested cockatoo shares some features with the kinetics reported previously in other animals and human beings.

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.

Intraosseous regional perfusion for treatment of septic physitis in a two-week-old foal.

A 2-week-old Morgan filly examined because of lameness of 5 days' duration was found, on the basis of clinical and radiographic findings, to have septic physitis of the distal end of the radius. The foal was treated by means of intraosseous regional perfusion with penicillin and amikacin and systemic administration of antimicrobials. Intraosseous regional perfusion was performed 3 times. The foal was anesthetized for the first episode of intraosseous regional perfusion, but was only sedated for the subsequent 2 episodes. Antimicrobials were administered systemically for 22 days. Foals with septic physitis are typically considered to have a guarded to poor prognosis for recovery; however, this treatment regimen resulted in relatively fast and uncomplicated resolution of the infection in this foal.