Evaluation and optimisation of propofol pharmacokinetic parameters in cats for target-controlled infusion.

The aim of this study was to develop and evaluate a pharmacokinetic model-driven infusion of propofol in premedicated cats. In a first step, propofol (10 mg/kg) was administered intravenously over 60 seconds to induce anaesthesia for the elective neutering of seven healthy cats, premedicated intramuscularly with 0.3 mg/kg methadone, 0.01 mg/kg medetomidine and 2 mg/kg ketamine. Venous blood samples were collected over 240 minutes, and propofol concentrations were measured via a validated high-performance liquid chromatography assay. Selected pharmacokinetic parameters, determined by a three-compartment open linear model, were entered into a computer-controlled infusion pump (target-controlled infusion-1 (TCI-1)). In a second step, TCI-1 was used to induce and maintain general anaesthesia in nine cats undergoing neutering. Predicted and measured plasma concentrations of propofol were compared at specific time points. In a third step, the pharmacokinetic parameters were modified according to the results from the use of TCI-1 and were evaluated again in six cats. For this TCI-2 group, the median values of median performance error and median absolute performance error were -1.85 per cent and 29.67 per cent, respectively, indicating that it performed adequately. Neither hypotension nor respiratory depression was observed during TCI-1 and TCI-2. Mean anaesthesia time and time to extubation in the TCI-2 group were 73.90 (±20.29) and 8.04 (±5.46) minutes, respectively.

Malignant rhabdoid tumor of the thoracic spine.

A case of malignant rhabdoid tumor of the spine and a description of its CT findings are presented. The CT demonstrated a heterogeneous contrast enhancing epidural mass associated with severe bony destruction of the adjacent vertebra and cord compression.

Embolization of blunt trauma in the pediatric patient.

The use of embolization for control of hemorrhage following blunt trauma is well accepted in the adult population. This paper describes 2 cases in which embolization techniques were used successfully to control hemorrhage following blunt trauma in pediatric patients.

Intravenous DSA and duplex sonography as screening examinations for carotid disease: comparison in 102 vessels.

Duplex sonography and intravenous digital subtraction angiography (DSA) were compared in 102 carotid bifurcations in 51 patients. Sonograms were adequate in 87 (85%) vessels and angiograms were adequate on at least one view in 86 (84%) vessels. An adequate image was obtained by one or the other method in all but two vessels (98%). Although most vessels were seen well on one view only on DSA, agreement with sonography was exact in 73% of compared vessels and acceptable in 96%. Furthermore, no difference was found in the rate of agreement with sonography for vessels seen well by DSA on two or more views compared with those seen well on one view only. It was concluded that DSA and sonography are comparable screening methods for carotid disease and that a suboptimal study by either can usually be compensated for by performance of the other.

Localization of carotid cavernous fistula using digital subtraction angiography.

Digital subtraction angiography (DSA), with its rapid imaging rate (30 video frames per second) and immediately available subtraction images, provides excellent vascular detail in localization of the exact site of internal carotid-cavernous fistula. In a patient with two fistulas, we successfully used DSA to determine the sites of fistula and accurately positioned detachable balloons to occlude them.

Percutaneous recanalization of iliac artery occlusions: an alternative to surgery in the high-risk patient.

Percutaneous transluminal angioplasty was performed successfully in three patients with total occlusions involving the iliac artery. Two patients had occlusion of the external iliac artery and the third patient had occlusion of the common iliac artery. The vessels were still patent at 3-12 months after the procedure. One complication occurred involving a thrombus in the common femoral artery of the diseased leg. The thrombus was surgically removed under local anesthesia. In high-risk patients, percutaneous transluminal angioplasty of total iliac artery occlusions may represent a viable alternative to surgery.

Treatment of advanced vascular disease with intra-arterial thrombolytic therapy followed by arterial dilatation.

A patient with severe arterial insufficiency was successfully treated with a combination of intra-arterial low-dose streptokinase and percutaneous transluminal dilatation. The judicious use of a combination of these two techniques may extend the application of each technique and allow salvage of some severely ischemic extremities.

Utility of CT-guided abdominal aspiration procedures.

Over 200 consecutive diagnostic needle aspiration procedures of the abdomen were performed under computed tomographic (CT) guidance. Biopsies were done of the liver in 88 patients, the pancreas in 28, the kidney in 20, and the retroperitoneum in 32; 30 underwent an aspiration procedure for characterization of an intraabdominal fluid collection. Accuracy of diagnosis was very high for hepatic (99%) and renal (100%) biopsies and in characterization of fluid collections (100%). Accuracy for retroperitoneal biopsy was 87.5% and for pancreatic biopsy 82%. Overall accuracy for all sites was 95%. There were one false-negative diagnosis for the liver and five false-negative diagnoses for the pancreas. Insufficient material was obtained for diagnosis in four instances of retroperitoneal biopsy. There were no false positives. The technique is facilitated by rapid CT scan time, large aperture gantry, and rapid CT image reconstruction. Twenty gauge needles were used more frequently than 22 gauge needles because of their greater rigidity and ease of control. CT-guided diagnostic aspiration procedures are particularly useful for diagnosis of small, deep-seated lesions and in evaluation of lesions found in severely ill patients. An experienced cytologist is essential to the success of the technique.

The role of computed tomography in pelvic fractures.

Adequate radiologic demonstration of the extent of pelvic fractures facilitates planning of their treatment by the orthopedic surgeon. Traditionally, this evaluation has been by conventional radiology. This report details results of computed tomography (CT) in the evaluation of pelvic fractures in 34 patients. In most cases, CT was able to identify and delineate the extent of fractures, demonstrate displacement of the involved bones, localize bone fragments and characterize joint derangements. Many of these features were better demonstrated at CT compared with conventional radiographs. In particular, in 10 patients loose bodies were seen at CT that were not evident on conventional radiography. The extent of associated soft tissue injury is also well shown by CT and demonstrated peripelvic or intraarticular fluid collections can be aspirated under CT guidance to rule out sepsis. This study suggests that CT is useful in the assessment of major pelvic fractures.

Effect of aminophylline on coronary circulation and cardiac metabolism.

Doses of aminophylline commensurate with human doses, administered intravenously to dogs under chloralose anesthesia cause an increase in heart rate, a decrease in mean systemic arterial blood pressure, a rise in cardiac output, coronary blood flow and myocardial oxygen consumption and an increase in the oxygen content of the coronary sinus blood which resulted in a decrease in the coronary oxygen arteriovenous difference as the oxygen content of the arterial blood remained essentially unchanged. This increase in coronary blood flow in the presence of a decrease in arterial blood pressure is obviously due to a decrease in the resistance of the coronary bed, which is probably due, at least partially, to dilatation of the coronary bed. Furthermore, since aminophylline decreases the coronary oxygen arteriovenous difference although it raises the myocardial oxygen consumption, it is concluded that aminophylline increases the coronary blood flow more than the myocardial oxygen consumption.