Francisco G. Laredo

Ultrasound-guided block of the sciatic and femoral nerves in dogs: a descriptive study.

Ten canine cadavers were used to investigate the anatomy and ultrasonographic approaches to the sciatic (ScN) and femoral (FN) nerves and to assess the accuracy of an ultrasound (US) guided technique to locate and block these nerves in the dog. The nerves of four sedated dogs were sought using US, blocked with 1% lidocaine and successful location confirmed by peripheral neurostimulation. The ScN was identified by US in all cases whereas the FN was not located in all cases. This study validates the usefulness of the US-guided technique to locate and block the ScN at the midfemoral level but the acoustic window of the inguinal region was less successful for locating and blocking the FN.

Clinical and radiographic study of bone and joint lesions in 26 dogs with leishmaniasis.

Twenty-six dogs with parasitologically confirmed leishmaniasis and abnormalities of gait were studied to determine the most common radiological patterns of bone and joint lesions. The clinical findings included either lameness, joint pain and crepitation, soft tissue swelling and/or muscle atrophy. Bone lesions were observed radiographically in 12 of the 26 dogs; the radius and ulna were affected in seven, the tibia in six and the femur in six. Joint lesions were observed radiographically in 15 of the 26 dogs; the carpus and stifle were affected in all 15, and the tarsus in nine. There was a tendency for the bones and joints to be affected bilaterally. The radiographic patterns observed were different in the long bones and the joints. In the long bones, the most common pattern was periosteal and intramedullary proliferation, involving the diaphyses and related to the nutrient foramen; in the joints, two patterns, either non-erosive or erosive polyarthritis with soft-tissue swelling, were observed. The changes observed in the synovial fluid were associated in most cases with osteolytic lesions. However, Leishmania organisms were identified in the synovial fluid from joints without bony radiographic changes.

Ventral ultrasound-guided suprainguinal approach to block the femoral nerve in the dog.

This prospective study assessed a ventral ultrasound-guided suprainguinal approach to block the femoral nerve (FN) in dogs. The anatomical features of the FN were evaluated in four canine cadavers. In another five cadavers, the FN was located by ultrasound-guidance and the accuracy of this technique was evaluated by injection of black ink and posterior evaluation of the degree of staining of the nerves. In five live dogs, the FN was blocked with 2% lidocaine. The distribution of lidocaine around the nerve and the presence of motor deficit were evaluated. The FN was easily located and accurately blocked in all cases. This new ultrasound-guided approach was reliable for blocking the FN and might be a suitable alternative to the traditional approaches described to block the FN in the dog.

Ultrasound-guided 'two-in-one' femoral and obturator nerve block in the dog: an anatomical study.

OBJECTIVE To evaluate the dye extent and distribution at the lumbar plexus (LP) of three volumes of local anaesthetic-methylene-blue solution administered close to the femoral nerve (FN) by the use of a ventral ultrasound (US)-guided suprainguinal approach (SIA). STUDY DESIGN Prospective experimental trial. ANIMALS Twenty mongrel canine cadavers weighing 17.7 ± 3.8 kg (mean ± SD). METHODS The left and right LP of two cadavers were dissected to identify the FN, obturator nerve (ON) and lateral femoral cutaneous nerve (LFCN). The extent and distribution of dye at the LP of each of three volumes of injectate of 0.2, 0.4 and 0.6 mL kg(-1) administered close to the FN by a ventral US-guided SIA then were studied in a further 18 dog cadavers (n = 6 per group). Staining of ≥2 cm along the target nerves was indicative of sufficient spread to produce a nerve block. RESULTS The ventral US-guided SIA allowed the observation of the FN within the iliopsoas muscle (IPM) in a total of 17 cadavers. The assessment of the dye extent and distribution revealed a similar pattern regardless of the injected volume. From the injection site, the spreading of injectate occurred in cranial, lateral and caudal directions. The FN and ON were effectively stained in all the cases. The LFCN was not effectively stained in any case. CONCLUSIONS AND CLINICAL RELEVANCE A volume of 0.2 mL kg(-1) administered close to the FN by a ventral US-guided SIA produced a sufficient distribution of the injectate within the IPM to produce effective staining of the FN and ON. This US-guided technique may be an appropriate alternative to previously reported techniques based on electrolocation to block the FN and ON in the dog.

Effects of altering the sequence of midazolam and propofol during co‐induction of anaesthesia

OBJECTIVE To assess the effects of varying the sequence of midazolam and propofol administration on the quality of induction, cardiorespiratory parameters and propofol requirements in dogs. STUDY DESIGN Randomized, controlled, clinical study. ANIMALS Thirty-three client owned dogs (ASA I-III, 0.5-10 years, 5-30 kg). METHODS Dogs were premedicated with acepromazine (0.02 mg kg(-1) ) and morphine (0.4 mg kg(-1) ) intramuscularly. After 30 minutes, group midazolam-propofol (MP) received midazolam (0.25 mg kg(-1) ) intravenously (IV) before propofol (1 mg kg(-1) ) IV, group propofol-midazolam (PM) received propofol before midazolam IV at the same doses, and control group (CP) received saline IV, instead of midazolam, before propofol. Supplementary boluses of propofol (0.5 mg kg(-1) ) were administered to effect to all groups until orotracheal intubation was completed. Behaviour after midazolam administration, quality of sedation and induction, and ease of intubation were scored. Heart rate (HR), respiratory rate, and systolic arterial blood pressure were recorded before premedication, post-premedication, after midazolam or saline administration, and at 0, 2, 5, and 10 minutes post-intubation. End-tidal CO2 and arterial oxygen haemoglobin saturation were recorded at 2, 5 and 10 minutes post-intubation. RESULTS Quality of sedation and induction, and ease of intubation were similar in all groups. Incidence of excitement was higher in the MP compared to CP (p = 0.014) and PM (p = 0.026) groups. Propofol requirements were decreased in MP and PM groups with respect to CP (p < 0.001), and in PM compared to MP (p = 0.022). The HR decreased after premedication in all groups, and increased after midazolam and subsequent times in MP (p = 0.019) and PM (p = 0.001) groups. Incidence of apnoea and paddling was higher in CP (p = 0.005) and MP (p = 0.031) groups than in PM. CONCLUSIONS AND CLINICAL RELEVANCE Administration of midazolam before propofol reduced propofol requirements although caused mild excitement in some dogs. Administration of propofol before midazolam resulted in less excitatory phenomena and greater reduction of propofol requirements.

Ultrasound-guided block of the feline sciatic nerve

This study was conducted to validate an ultrasound-guided technique to block the sciatic nerve in cats. An anatomical study was first carried out in four feline cadavers to evaluate the feasibility of the glutea (cranial and caudal), femoris and poplitea ultrasonographical approaches for the sciatic nerve block. The results showed that the femoris approach was optimal because the region was free of vascular and bony structures, and the needle was easily visualised in-plane. Then, the efficacy of the femoris ultrasonographical approach to block the sciatic nerve was tested in six healthy adult experimental cats. A dose of 2 mg/kg lidocaine 2% diluted in saline to a final volume of 1 ml was administered in all cats. The blockade was successful in all cases and the cats recovered uneventfully. This study shows the usefulness of the femoris approach in performing an ultrasound-guided blockade of the sciatic nerve in cats.

Comparative study of air coagulation, fibrin sealant, and suture in experimental liver injury

OBJECTIVE To test the effects of hot air coagulation, fibrin sealant, and horizontal mattress sutures on haemostasis and regeneration in experimental hepatectomy. DESIGN Randomised laboratory experiment. SETTING Teaching hospital, Spain. MATERIAL 200 rats divided into four groups (three experimental [n=60 in each] and one control [n=20]). INTERVENTIONS Hepatic injuries were repaired by suture, coagulation, or fibrin sealant in the three experimental groups. The control group was used only to supply baseline blood samples. 10 animals in each experimental group were killed at 3, 5, 10, 25, 40, and 60 days. MAIN OUTCOME MEASURES Time taken to achieve haemostasis, and histopathological scores of healing. RESULTS Mattress sutures took mean (SEM) of 346 (7) seconds to control the haemorrhage and allow the liver to regain its shape and 4 rats developed abscesses (7%). Fibrin sealant achieved haemostasis immediately and the liver regained its shape in 58 (2) seconds; 2 rats (3%) developed abscesses. Hot air coagulation achieved haemostasis in 27 (1) seconds and there were no abscesses. CONCLUSION Fibrin sealant was the best technique because it achieved immediate haemostasis and speedy regeneration. However, hot air coagulation is a useful and cheaper alternative.

Left perinephric abscess associated with nephrolithiasis and bladder calculi in a bitch.

An eight-year-old, entire female Pekingese cross, weighing 3–8 kg, had been inappetent with fever, depression, abdominal pain, vomiting and diarrhoea for seven days. The radiographic and ultrasonographic findings were consistent with glomerulonephritis, nephrolithiasis in both kidneys, bladder calculi and an accumulation of fluid in the left perinephric space. The clinical signs, together with the results of the diagnostic imaging, suggested that this fluid could be pus. A definitive diagnosis of a subcapsular abscess in the left kidney was established when this kidney was removed surgically. A histopathological examination of the kidney revealed a diffuse suppurative interstitial nephritis, membranous glomerulonephritis and an abscess invading the perinephric adipose tissue from the renal cortex. Twelve months after surgery the dog remains clinically stable, but owing to the disease of its remaining kidney its long-term prognosis is poor.

The bispectral index during recovery from halothane and sevoflurane anaesthesia in horses

OBJECTIVE To record the bispectral index (BIS) when horses moved during either halothane or sevoflurane anaesthesia and when they made volitional movements during recovery from these anaesthetics. STUDY DESIGN Randomized prospective clinical study. ANIMALS Twenty-five client-owned horses undergoing surgery aged 8.8 (± 5.3; 1-19) years (mean ± SD; range). METHODS Baseline BIS values were recorded before pre-anaesthetic medication (BISB) and during anaesthesia (BISA) maintained with halothane (group H; n = 12) or sevoflurane (group S; n =13) at approximately 0.8-0.9 × minimum alveolar concentrations (MAC). Bispectral indices were recorded during the surgery when unexpected movement occurred (BISMA), during recovery when the first movement convincingly associated with consciousness was observed (BISM1) and once sternal recumbency was achieved (BISST). RESULTS No significant difference in BISM1 was found between halothane- (85 ± 7; 75-93) and sevoflurane- (87 ± 10; 70-98) anaesthetized horses although BISA was significantly (p = 0.0002) lower in group S (62 ± 7; 53-72) than group H (74 ± 7; 60-84). Differences between BISM1 and BISA were significant in sevoflurane (p = 0.00001) and halothane recipients (p = 0.002) but were greater in group S (25 ± 9; 4-38) compared with group H (12 ± 10; -9-25). In six of eight horses, BISMA values ranged between those recorded during anaesthesia and at first movement. CONCLUSIONS AND CLINICAL RELEVANCE Bispectral indices appear to approximate levels of unconsciousness, suggesting that monitoring the BIS may assist equine anaesthesia. However, it does not predict intra-operative movement.

IMAGING DIAGNOSIS-INFILTRATIVE LIPOMA CAUSING SPINAL CORD AND LUMBAR NERVE ROOT COMPRESSION IN A DOG

A 12-year-old, male, fox terrier dog presented with an abnormal gait of the left pelvic limb. Computed tomography revealed a large, homogeneous, hypoattenuating, noncontrast enhancing mass within the left epaxial muscles that invaded the L5-6 vertebral canal and caused spinal cord compression. Imaging findings were consistent with an infiltrative lipoma. The mass was removed and a left hemilaminectomy was performed in the affected area. Histopathology confirmed the mass to be an infiltrative lipoma. The dog recovered and regained neurologic function within 2 weeks. Computed tomography assisted preoperative planning by characterizing the shape, size, and location of the mass.