Validation of laser doppler flowmetry to measure dermal blood flow of the pinnae in dogs with pinnal alopecia.

BACKGROUND: Laser Doppler flowmetry (LDF) is a noninvasive method of measuring regional blood flow in humans. However, this method has not been widely applied to measure blood flow in dogs. HYPOTHESIS/OBJECTIVES: We hypothesised that LDF can measure changes in blood flow in canine pinnae accurately. The objectives were to determine whether LDF could accurately detect dermal blood flow changes in canine pinnae caused by haemodynamic drugs and characterize the dermal blood flow in dogs with pinnal alopecia. ANIMALS: Sixteen laboratory-owned healthy dogs, 25 client-owned healthy control dogs and six dogs with pinnal alopecia suspected to be secondary to ischaemic dermatoses. MATERIALS AND METHODS: Clinical doses of the haemodynamic drugs atropine, medetomidine and dibutyryl cyclic adenosine monophosphate (dBcAMP), as well as topical dBcAMP, were administered to healthy beagles. Subsequently, an LDF apparatus was attached to the pinnae to analyse changes in dermal blood flow. Finally, LDF was used to measure auricular dermal blood flow in dogs with pinnal alopecia compared to healthy dogs. RESULTS: Dermal blood flow increased after atropine injection, during dBcAMP infusion and after topical dBcAMP ointment application, and decreased after medetomidine injection. Auricular dermal blood flow (in mL/min/100 g tissue) was significantly (p < 0.05) lower in dogs with pinnal alopecia than in healthy dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Laser Doppler flowmetry is useful for measuring dermal blood flow in canine pinnae; it can be a noninvasive method to monitor ischaemic conditions of dog skin.

Local α1-adrenergic blockers: An alternative for sheep cervix dilation?

To facilitate transcervical artificial insemination in sheep, the effects of local treatment with α1-adrenergic receptor antagonists on cervix dilation and hemodynamics were evaluated. Ewes (n = 7) were subjected to oestrous synchronisation every 40 days and assigned to treatments in a Latin square experimental design (seven animals × seven periods) with a factorial treatment arrangement (A × B), Factors A (prazosin or tamsulosin) and B (1, 2, or 4 mg/animal). Ewes of the six treatment groups (P1, P2, P4, T1, T2, and T4) were administered α1-adrenergic receptor antagonists while those of the control group (CG) were administered only α1-adrenergic antagonist carrier agent. Distance that the transcervical catheter penetrated without cervical resistance, mean arterial pressure, and uterine artery dopplerfluxometry were evaluated before and after 30 min, 1, 2, 4, 8, and 10 h of treatment. Catheter penetration distance was greater in ewes of the T4 and P4 groups (P < 0.01), with there being a positive correlation between dose and distance (r = 0.243). The penetration distance was similar (P = 0.84) for treated groups, with the greatest penetration occurring 2, 4, and 6 h after treatment (P < 0.01). The passage into the uterine lumen was greater (P = 0.013) in ewes of the P4 (17.9 %) and T4 (19.6 %) groups. There were no effects on blood pressure or uterine blood flow (P> 0.05). These preliminary results indicate there are benefits of treatment with 4 mg/animal of tamsulosin or prazosin in catheter passage through the sheep cervix 2-6 h after administration without hemodynamic effects.

Evaluation of surface blood flow in intact and ruptured canine cruciate ligaments using laser Doppler flowmetry.

OBJECTIVE: To evaluate the usefulness of laser Doppler flowmetry (LDF) to measure surface blood flow in canine cruciate ligaments, compare measurements in different sites of intact and partially ruptured canine cranial cruciate ligaments (CrCL) and intact caudal cruciate ligaments (CaCL), and investigate any association between surface blood flow in partially ruptured CrCL and synovitis or duration of clinical signs. STUDY DESIGN: Case-controlled clinical study. ANIMALS: Sixteen dogs with partially ruptured CrCL and five dogs with intact CrCL. METHODS: Blood cell flux (BCF) readings during three measurement cycles using LDF at two sites in each ligament (mid-substance and the distal portion of the CrCL, and mid-substance and the proximal portion of the CaCL) were recorded. Synovial changes were graded grossly and histologically using the Osteoarthritis Research Society International histopathology scoring system. RESULTS: The within-run coefficients of variation (CV) for a single BCF measurement cycle were 12.2% and 12.7% in the ruptured and intact CrCL groups, respectively. The between-run CV for three measurement cycles was 20.8% and 14.8%, respectively. The intraclass correlation coefficient (ICC, absolute agreement) was 0.66 for a single measurement cycle and 0.86 for the average of three cycles. No difference in average BCF readings was found between any two sites in either group, but BCF readings in both CrCL sites were significantly higher in the ruptured CrCL group than the intact CrCL group. No associations between BCF and synovial grades or duration of lameness were identified. CONCLUSIONS: Laser Doppler flowmetry can be used to assess surface blood flow in intact and partially ruptured canine cruciate ligaments with acceptable precision. Using this method, surface blood flow appears greater in partially ruptured canine CrCL than intact CrCL. Further studies are required to determine if this is a sequela of trauma or synovitis.

Temporal and concentration effects of isoflurane anaesthesia on intestinal tissue oxygenation and perfusion in horses.

The aim of this study was to assess the effect of duration of anaesthesia and concentration of isoflurane on global perfusion as well as intestinal microperfusion and oxygenation. Nine Warmblood horses were premedicated with xylazine; anaesthesia was induced with midazolam and ketamine, and maintained with isoflurane. Horses were ventilated to normocapnia. During 7 h of anaesthesia, mean arterial blood pressures (MAP), heart rate, central venous pressure, pulmonary artery pressure, expiratory isoflurane concentration (ETIso) and cardiac output using lithium dilution were measured; cardiac index (CI) was calculated. Intestinal microperfusion and oxygenation were measured using laser Doppler flowmetry and white-light spectrophotometry. Surface probes were placed via median laparotomy on the serosal and mucosal site of the jejunum and the pelvic flexion of the colon. After 3 h of constant ETIso (1.4%), ETIso was increased in 0.2% increments up to 2.4%, followed by a decrease to 1.2% and an increase to 1.4%. The CI and MAP decreased continuously with increasing ETIso to 40 ± 5 mL/kg/min and 52 ± 8 mmHg, respectively. Microperfusion and oxygenation remained unchanged until an ETIso of 2.0% resulted in CI and MAP of 48 ± 5 mL/kg/min and 62 ± 6 mmHg, respectively, and then decreased rapidly. When ETIso decreased back to baseline, CI, MAP, microperfusion and oxygenation recovered to baseline. Isoflurane concentration but not duration of isoflurane anaesthesia influenced central and intestinal oxygenation and perfusion in healthy horses. Under isoflurane, intestinal perfusion appeared to be preserved until a threshold MAP or blood flow was reached.

Effect of locally injected autologous platelet-rich plasma on second intention wound healing of acute full-thickness skin defects in dogs.

OBJECTIVES: Second intention wound healing may be impaired by wound and host factors and thus more advanced therapies are required for a fast and satisfactory outcome. Platelet-rich plasma (PRP), rich in growth factors and cytokines essential for tissue repair, could improve wound healing. The purpose of this experimental study was to evaluate the effect of locally injected autologous PRP on second intention healing of acute full-thickness skin defects in dogs. METHODS: Three 2 x 2 cm full-thickness skin defects were created bilaterally on the dorsolateral area of the trunk of six Beagle dogs. The wounds of one randomly selected side received PRP treatment, whereas the contralateral wounds were left untreated (controls). Wound healing was evaluated by planimetry, laser-Doppler flowmetry measurements of tissue perfusion, and histologically. RESULTS: The rate of wound healing did not differ significantly between the two groups. Tissue perfusion was significantly higher in the PRP-treated group (p = 0.008) compared to controls on day 10. Histological evaluation revealed a trend towards greater collagen production and a significantly better collagen orientation (p = 0.019) in PRP-treated wounds on day 20. CLINICAL SIGNIFICANCE: Locally injected autologous PRP does not accelerate the healing process, but increases tissue perfusion and may promote the formation of organized collagen bundles in acute full-thickness skin defects in dogs.

Triplex Doppler evaluation of the testes in dogs of different sizes / Avaliação Triplex Doppler dos testículos de cães de tamanhos diferentes

This study aimed to assess whether there are differences in Doppler velocimetry parameters between different sizes. Twenty dogs were equally divided into small and large groups used in this study. The dogs were evaluated using Triplex ultrasound. Testicular artery was located by Colour Doppler in the spermatic cord, marginal to the testes and intratesticular segments and then, spectral Doppler were used to calculate: peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI). The mean testicular volume in the left side was significantly higher than the right side, in both groups. Doppler examination showed higher velocities (EDV) at spermatic cord in large dogs; marginal to the testes was observed higher velocities in small dogs; intratesticular region no differences were observed (P < 0.05) and within the groups differences between segments of the artery were also observed for each parameter. The results showed that there are differences in Doppler velocimetry parameters between different sizes.(AU)

Este trabalho teve como objetivo verificar se existem diferenças nos parâmetros dopplervelocimétricos entre cães de diferentes portes. Para tanto, foram utilizados 20 cães, sendo 10 cães de pequeno porte e 10 cães de grande porte. Foram avaliados pelo Triplex Doppler para localização da artéria testicular nos segmentos de cordão espermático, marginal ao testículo e intratesticular. Após isso, o Doppler espectral foi acionado para cálculo dos parâmetros de velocidade de pico sistólico (VPS), velocidade diastólica final (VDF) e índices de resistência (IR) e pulsatilidade (IP). O volume testicular médio do testículo esquerdo foi significativamente maior que o direito em ambos os grupos. Ao Doppler, foram observadas diferenças dos valores entre os portes, sendo as velocidades no cordão espermático superiores nos animais de grande porte (P < 0,05) e dentro dos grupos também foram observadas diferenças entre as regiões da artéria testicular. Diante do exposto, conclui-se que existem diferenças nos parâmetros dopplervelocimétricos quando comparados animais de diferentes portes, além disso, os parâmetros dopplervelocimétricos são diferentes dependendo da região em que são mensurados.(AU)

Assessment of mitral regurgitation severity by Doppler color flow mapping of the vena contracta in dogs.

BACKGROUND: Quantitative and semiquantitative methods have been proposed for the assessment of MR severity, and though all are associated with limitations. Measurement of vena contracta width (VCW) has been used in clinical practice. OBJECTIVE: To measure the VCW in dogs with different levels of MR severity. ANIMALS: Two hundred and seventy-nine dogs were classified according to 5 levels of MR severity. METHODS: This was a retrospective study. EROA and regurgitant volume calculated by the PISA method, were measured and indexed to BSA. Descriptive statistics were calculated for VCW and VCW index for all categories of MR severity. Spearman's rank correlation coefficients (ρs ) were calculated to compare the results of the different methods (VCW and VCW index vs RV PISA, RV PISA index, EROA, EROA index), and between VCW and VCW index versus MR severity. RESULTS: All Spearman's rank correlation coefficients were significant (P < .001). The median values of VCW resulted of 2.9 mm (IQR 3.4-2.5) and of 4.6 mm (IQR 5.4-4.1) in the groups previously classified as mild-to-moderate and moderate-to-severe, respectively. The median values of VCW index resulted of 4.4 mm/m(2) (IQR = 5.5-4.2) in mild-to-moderate MR and of 10.8 mm/m(2) (IQR = 12.8-9.4) in moderate-to-severe MR. CONCLUSION AND CLINICAL IMPORTANCE: This is not a validation study against any previously validated invasive gold standard, the VCW method has proved easy to employ and it might be an additional tool in quantifying disease severity that supports, rather than replace, data coming from other techniques in daily clinical practice and research.

Doppler blood pressure measurement in pigs during anaesthesia.

To determine the accuracy of Doppler blood pressure measurement in anaesthetised pigs eight large white pigs (Sus scrofa) were anaesthetised with zolazepam and tiletamine as Zoletil 100 (4 mg/kg) and xylazine (2 mg/kg) by intramuscular injection followed by isoflurane in 100% oxygen. Blood pressure measurements were recorded using a Doppler probe on the radial artery and a catheter in the femoral artery connected to a transducer. The sample mean of the Doppler measurements were compared with the sample mean of the invasive systolic arterial blood pressure while accounting for the heart rate, end-tidal CO2 and temperature. The predicted error of the Doppler was greatest when pigs were hypotensive and normothermic: 11 mmHg (CI: 6-15). Doppler measurements should be interpreted with caution in anaesthetised pigs that are hypotensive and normothermic.

Development of a wireless sensor for the measurement of chicken blood flow using the laser Doppler blood flow meter technique.

Here, we report the development of an integrated laser Doppler blood flow micrometer for chickens. This sensor weighs only 18 g and is one of the smallest-sized blood flow meters, with no wired line, these are features necessary for attaching the sensor to the chicken. The structure of the sensor chip consists of two silicon cavities with a photo diode and a laser diode, which was achieved using the microelectromechanical systems technique, resulting in its small size and significantly low power consumption. In addition, we introduced an intermittent measuring arrangement in the measuring system to reduce power consumption and to enable the sensor to work longer. We were successfully able to measure chicken blood flow for five consecutive days, and discovered that chicken blood flow shows daily fluctuations.

Comparison of direct and Doppler arterial blood pressure measurements in rabbits during isoflurane anaesthesia.

OBJECTIVE: To measure the level of agreement between Doppler measured (DOP) arterial blood pressure (ABP) in the forelimb and directly measured (DIR) auricular systolic ABP (SAP) and mean ABP (MAP) in isoflurane-anaesthetized rabbits. STUDY DESIGN: Prospective clinical study. ANIMALS: Data were analysed from 17 of 24 healthy rabbits, weighing 1.3-2.8 kg. METHODS: Rabbits were anaesthetized for neutering using a standardized protocol. A 26G catheter placed in an auricular artery was connected via heparinised saline filled non-compliant tubing (regularly flushed) to a calibrated pressure transducer (zeroed level with the thoracic inlet) to obtain DIR ABP. A cuff was placed proximal to the carpus (approximately level with the thoracic inlet) and a Doppler transducer sited over the dorsal carpal branch of the radial artery to obtain DOP ABP. Simultaneous DIR and DOP ABP recordings were made every 5-10 minutes during anaesthesia. Agreement was assessed as described by Bland JM & Altman (2007). RESULTS: Mean ± SD cuff width: limb circumference ratio was 0.50 ± 0.04. Mean between-method differences ± SD, DIR SAP- DOP and DIR MAP- DOP, were +1 ± 8 and -13 ± 8 mmHg respectively. The 95% limits of agreement between DIR SAP and DOP and between DIR MAP and DOP were -14 to +17 and -28 to +2 mmHg respectively. Differences between DIR SAP and DOP were ≤ 10 mmHg 85% of the time. Defining hypotension as either DIR SAP < 80 mmHg or DIR MAP < 60 mmHg, and taking DOP ABP of <80 mmHg to indicate hypotension, sensitivity and specificity were 92% and 67% respectively. CONCLUSIONS: Good agreement was found between DIR SAP and DOP. Doppler measurements below 80 mmHg are a reliable indicator of arterial hypotension. CLINICAL RELEVANCE: DOP is acceptable for monitoring ABP in isoflurane-anaesthetized rabbits and is useful for detection of hypotension.

Influence of durotomy on laser-Doppler measurement of spinal cord blood flow in chondrodystrophic dogs with thoracolumbar disk extrusion.

OBJECTIVES: To assess influence of durotomy on spinal cord blood flow (SCBF) in chondrodystrophic dogs with thoracolumbar disk extrusion. STUDY DESIGN: Prospective cohort study. ANIMALS: Chondrodystrophic dogs with thoracolumbar disk extrusion (n = 11). METHODS: Diagnosis was based on neurologic signs, magnetic resonance imaging (MRI) findings, and surgical confirmation. Regional SCBF was measured 3 times intraoperatively by laser-Doppler flowmetry: (1) before surgical decompression; (2) immediately after decompression by hemilaminectomy-durotomy; and (3) after 15 minutes of lesion lavage. A standardized hemilaminectomy and durotomy performed by the same neurosurgeon, was used to minimize factors that could influence measurement readings. RESULTS: A significant increase in intraoperative SCBF was found immediately after spinal cord decompression and durotomy in dogs but SCBF returned to previous levels or lower after 15 minutes of lavage. Changes in SCBF were not associated with duration of clinical signs; neurologic status, degree of spinal cord compression, or signal intensity changes as assessed by MRI. CONCLUSION: Durotomy does not increase SCBF in dogs with disk extrusion associated spinal cord compression.

Live imaging of rat embryos with Doppler swept-source optical coherence tomography.

The rat has long been considered an excellent system to study mammalian embryonic cardiovascular physiology, but has lacked the extensive genetic tools available in the mouse to be able to create single gene mutations. However, the recent establishment of rat embryonic stem cell lines facilitates the generation of new models in the rat embryo to link changes in physiology with altered gene function to define the underlying mechanisms behind congenital cardiovascular birth defects. Along with the ability to create new rat genotypes there is a strong need for tools to analyze phenotypes with high spatial and temporal resolution. Doppler OCT has been previously used for 3-D structural analysis and blood flow imaging in other model species. We use Doppler swept-source OCT for live imaging of early postimplantation rat embryos. Structural imaging is used for 3-D reconstruction of embryo morphology and dynamic imaging of the beating heart and vessels, while Doppler-mode imaging is used to visualize blood flow. We demonstrate that Doppler swept-source OCT can provide essential information about the dynamics of early rat embryos and serve as a basis for a wide range of studies on functional evaluation of rat embryo physiology.

Ischemic stroke in mice and rats.

Ischemic stroke occurs most often in the territory of the middle cerebral artery (MCA) in humans. Since its description in rats more than two decades ago, the minimally invasive intraluminal suture occlusion of MCA is an increasingly used model of stroke in both rats and mice due to its ease of inducing ischemia and achieving reperfusion under well-controlled conditions. This method can be used under the guidance of laser-Doppler flowmetry to ascertain the magnitude of occlusion or reperfusion and to decrease the rate of subarachnoid hemorrhage. Ninety minutes of transient ischemia in the territory of MCA results in substantial and reproducible ischemic lesions in both the striatum and the cortex, with characteristics of lesion core and penumbra. Thus, this model is applicable to neuroprotective drug studies, including ischemic brain lesion evaluation (either in vivo with magnetic resonance imaging or post-mortem with brain tissue staining) and neurological status (motor deficits simply assessed by a six-point neurological score scale) as outcome parameters.

Laser-Doppler measurements of spinal cord blood flow changes during hemilaminectomy in chondrodystrophic dogs with disk extrusion.

OBJECTIVES: (1) To assess spinal cord blood flow (SCBF) during surgical treatment of disk extrusion in dogs and (2) to investigate associations between SCBF, clinical signs, presurgical MRI images, and 24-hour surgical outcome. STUDY DESIGN: Cohort study. ANIMALS: Chondrodystrophic dogs with thoracolumbar disk extrusion (n=12). METHODS: Diagnosis was based on clinical signs and MRI findings, and confirmed at surgery. Regional SCBF was measured intraoperatively by laser-Doppler flowmetry before, immediately after surgical spinal cord decompression, and after 15 minutes of lavaging the lesion. Care was taken to ensure a standardized surgical procedure to minimize factors that could influence measurement readings. RESULTS: A significant increase in intraoperative SCBF was found in all dogs (Wilcoxon's signed-rank test; P=.05) immediately after spinal cord decompression and after 15 minutes. Changes in SCBF were not associated with duration of clinical signs; initial or 24-hour neurologic status; or degree of spinal cord compression assessed by MRI. CONCLUSION: SCBF increases immediately after spinal cord decompression in dogs with disk herniation; however, increased SCBF was not associated with a diminished 24-hour neurologic status. CLINICAL RELEVANCE: An increase in SCBF does not appear to be either associated with the degree of spinal cord compression or of a magnitude sufficient to outweigh the benefit of surgical decompression by resulting in clinically relevant changes in 24-hour outcome.

Alpha-chloralose is a suitable anesthetic for chronic focal cerebral ischemia studies in the rat: a comparative study.

alpha-Chloralose is widely used as an anesthetic in studies of the cerebrovasculature because it provides robust metabolic and hemodynamic responses to functional stimulation. However, there have been no controlled studies of focal ischemia in the rat under alpha-chloralose anesthesia. Artificially ventilated rats were prepared using 1.2-1.5% isoflurane anesthesia for filament occlusion of the right middle cerebral artery (MCA), and anesthesia was either switched to alpha-chloralose (60 mg/kg bolus, 30 mg/kg/h; n=10) or was maintained on 1% isoflurane (n=10). Following temporary MCA occlusion EEG was monitored from a screw electrode and changes in cerebral blood flow (rCBF) measured with a laser Doppler probe placed over the ischemic cortex. This study shows that alpha-chloralose is a safe anesthetic for ischemia studies and provides excellent survival. Compared with isoflurane, the cortical and total infarct volumes are larger in the alpha-chloralose-anesthetized animals, while the functional outcome at 72 h is similar. The total duration of peri-infarct flow transients (PIFTs) is also significantly longer in alpha-chloralose-anesthetized animals. The average amplitude of the flow transients showed a good correlation with the extent of edema in all animals as did the total duration of non-convulsive seizures (NCS) in the alpha-chloralose-anesthetized animals.

Comparison of Doppler-derived aortic velocities obtained from various transducer sites in healthy dogs and cats.

In normal dogs and dogs with subaortic stenosis, it is known that the subcostal transducer site provides higher left ventricular ejection velocities than does the left apical site. We hypothesized that aortic flow velocities could also be obtained from the right parasternal long-axis view, optimized for the placement of the Doppler cursor as parallel as possible into the aortic root. In 15 healthy dogs and 13 healthy cats, high-pulsed repetition frequency Doppler flow velocity measurements in the proximal aorta were performed using two-dimensional echocardiographic guidance. The mean [ +/- standard error of the mean (SEM)] peak aortic flow velocities in healthy dogs were as follows: subcostal site 1.46 +/- 0.05 m/s; apical site 1.12 +/- 0.06 m/s; right parasternal long-axis site 1.09 +/- 0.05 m/s. In healthy cats, the following peak aortic flow velocities were observed: apical site 0.87 +/- 0.03m/s; right parasternal long-axis site 0.87 +/- 0.03 m/s. Aortic flow velocities obtained from the subcostal site were significantly higher in healthy dogs than those obtained from the left apical and right parasternal long-axis site (P< 0.001). There was no statistical difference between the peak aortic flow velocities obtained from right parasternal long-axis and left apical transducer position in all groups. We conclude therefore that right parasternal long-axis and left apical-derived aortic flow velocities are similar and may be used interchangeably in healthy dogs and cats.

Evaluation of laser Doppler flowmetry for measurement of capillary blood flow in the stomach wall of dogs during gastric dilatation-volvulus.

OBJECTIVES: To validate laser doppler flowmetry (LDF) for measurement of blood flow in the stomach wall of dogs with gastric dilatation-volvulus (GDV). ANIMALS: Six purpose-bred dogs and 24 dogs with naturally occurring GDV. STUDY DESIGN: Experimental and clinical. METHODS: Capillary blood flow in the body of the stomach and pyloric antrum was measured with LDF (tissue perfusion unit (TPU) before and after induction of portal hypertension (PH) and after PH plus gastric ischemia (GI; PH + GI) and compared with flow measured by colored microsphere technique. Capillary flow was measured by LDF in the stomach wall of dogs with GDV. RESULTS: PH and PH+GI induced a significant reduction in blood flow in the body of the stomach (P = .019). A significant positive correlation was present between percent changes in capillary blood flow measured by LDF and colored microspheres after induction of PH + GI in the body of the stomach (r = 0.94, P = .014) and in the pyloric antrum (r = 0.95, P = .049). Capillary blood flow measured in the body of the stomach of 6 dogs that required partial gastrectomy (5.00+/-3.30 TPU) was significantly lower than in dogs that did not (28.00+/-14.40 TPU, P = .013). CONCLUSIONS: LDF can detect variations in blood flow in the stomach wall of dogs. CLINICAL RELEVANCE: LDF may have application for evaluation of stomach wall viability during surgery in dogs with GDV.

Fluxometria eco-power-doppler da artéria oftálmica externa em gatos (Felis catus Linnaeus, 1758) / Eco-power-doppler arterial flow from the external ophthalmic artery in cats (Felis catus Linnaeus, 1758) / Flujometria por ultrasonido de la arteria oftálmica externaen gatos

RESUMO: Os avanços tecnológicos dos meios diagnósticos benefi ciam a Medicina Veterinária. Para que novas tecnologias sejam utilizadas, são necessárias informações sobre os padrões normais para cada tipo de exame, o que possibilita sua utilização na rotina e destinação, adequadamente, a cada paciente. A fl uxometria ultra-sonográfi ca está começando a ser utilizada em Medicina Veterinária com fi nalidades e propósitos diversos. Para destiná-la a um fi m específi co, o presente trabalho teve por objetivo verifi car a fl uxometria ultra-sonográfi ca da artéria oftálmica externa em gatos. Para tanto, foram utilizados 20 gatos sem raça defi nida, 12 machos e 8 fêmeas, com massa corporal entre 2,0 e 4,0 kg, hígidos, provenientes da Sociedade de Amparo aos Animais de Umuarama ­ PR. Os animais foram anestesiados pela associação de tiletamina e zolazepam, administrada por via intramuscular, na dose de 6,0 mg/kg. A fl uxometria da artéria oftálmica externa foi obtida por meio do equipamento de ultra-sonografi a Toshiba Powervision ATL-HDI 3500, dotado de "eco-doppler", com transdutor setorial de 6,0 MHz, aplicado diretamente sobre a córnea. Cada olho teve o fl uxo de sua artéria aferido pelo programa do próprio aparelho, sendo tomadas três amostras. O índice de resistência vascular foi calculado com base nos valores do fl uxo sistólico e diastólico médio de cada vaso. Os valores foram tabulados e teste t de Student foi aplicado para verifi cação de diferenças entre as médias. No olho direito, obteve-se velocidade de fl uxo de 41,3 ± 14,28 cm/seg para a artéria oftálmica externa, em sístole, e 23,95 ± 11,46 cm/seg, em diástole. No olho esquerdo, 42,75 ± 12,64 cm/seg, em sístole, e 25,45 ± 9,61 cm/seg, em diástole. Não houve diferença signifi cativa entre os olhos. O índice de resistência vascular calculado foi de 0,4175 para a artéria oftálmica externa, no olho direito, e 0,4015 no olho esquerdo, sem diferença signifi cativa entre os olhos. Os resultados apontam para um mecanismo intrínseco de controle do fl uxo, controlado por fatores locais na artéria oftálmica externa, e os valores do índice de resistência denotam uma artéria de baixo fluxo

ABSTRACT: Veterinary medicine is benefi ted by technological advances in diagnosis. In order that new technologies may be used, information about normal standards for each type of examination is necessary, so that they may be used routinely and adequately prescribed for each patient. The Doppler ultrasound is beginning to be used in veterinary medicine for diverse purposes. The objective of this study is to verify the Doppler ultrasound fl ow of the external ophthalmic artery in cats. There were used 20 mixed breed cats, being 12 males and eight females, weighing from 2.0 to 4.0 kg, supplied by the Amparo aos Animais Society, an animal shelter from the city of Umuarama, State of Paraná, Brazil. The animals were anesthetized with 6.0 mg/kg of the association tiletamine plus zolazepam, given by intramuscular route. The fl ow of the external ophthalmic artery was measured through the ultrasound equipment Toshiba Powervision ATL-HDI 3500, with an echo-Doppler and a sectorial transducer of 6.0 MHz, directly applied to the cornea. Each eye had the artery fl ow surveyed by the equipment's own software, in which three samples have been taken. The vascular resistance index was calculated based on the mean values of systolic and diastolic fl ow of each vessel. The values were tabulated and Student t test was applied to verify differences between the averages. In the right eye, the value for the external ophthalmic artery fl ow was 41.30 ± 14.28 cm/sec, in systole, and 23.95 ± 11.46 cm/seg, in diastole. For the left eye, the value was 42.75 ± 12.64 cm/sec, in systole, and 25.45 ± 9.61 cm/sec, in diastole. There were no signifi cant differences between the eyes. The calculated index of vascular resistance was 0.4175 ± 0.0774 for the external ophthalmic artery in the right eye, and 0.4015 ± 0.0719 for the left eye, without signifi cant difference between the eyes. The results point out to an intrinsic mechanism of fl ow control, controlled by local factors in the external ophthalmic artery, and the resistance index values denote a low fl ow artery

RESUMEN: La medicina veterinaria se benefi cia de los adelantos tecnológicos en diagnóstico. El conocimiento de los padrones normales para cada tipo y examen es fundamental para que se puedan usar nuevas tecnologías, posibilitando su empleo rutinario yla indicación adecuada a cada paciente. El objetivo de este estudio fue verifi car la fl ujometría por ultrasonido de la arteria oftálmica externa en gatos. Se emplearon 20 gatos sin raza defi nida, 12 machos y ocho hembras, que provinieron de la Sociedad de Amparo a los Animales de la ciudad de Umuarama, Estado de Paraná, Brasil. Los animales fueron anestesiados con 6.0 mg/kg de la asociación de tiletamina y zolazepam, ministrados por vía intramuscular. El fl ujo de la arteria oftálmica externa fue mensurado por medio del equipo del ultrasonido Toshiba Powervision ATL-HDI 3500, con un eco-doppler y un transductor sectorial de 6.0 MHz, directamenteaplicado a la córnea. Cada ojo tenía el fl ujo de la arteria evaluado por el propio programa del equipo, tomándose tres muestras. El índice de resistencia vascular se calculó basado en los valores promedios de fl ujo sistólico y diastólico de cada vaso. Los valores fueron tabulados y se aplicó el teste t de Student para verifi car diferencias entre los promedios. En el ojo derecho, el valor para el fl ujo de la arteria oftálmica externa fue 41,30 ± 14.28 cm/sec, en sístole, y 23,95 ± 11,46 cm/seg, en diástole. Para el ojo izquierdo, el valor fue 42,75 ± 12,64 cm/seg, en sístole, y 25,45 ± 9,61 cm/sec, en diastole. No se observó diferencia signifi cante entre los ojos. El índice calculado de resistencia vascular fue 0,4175 ± 0,0774 para la arteria oftálmica externa en el ojo derecho, y 0.4015 ± 0.0719 para el ojo izquierdo, sin diferencia signifi cante entre los ojos. Los resultados apuntan para un mecanismo intrínseco de control de fl ujo, controlado por factores locales en la arteria oftálmica externa, y los valores del índice de resistencia denotan una arteria de bajo fl ujo

Skeletal muscle blood flow in anaesthetized horses. Part I: measurement techniques.

OBJECTIVE: The objective of this review was to describe the methodology and limitations of techniques that have been used to measure skeletal muscle blood flow in anaesthetized horses. DATABASE USED: Pubmed, personal files. CONCLUSION: Numerous techniques have been used in horses to study skeletal muscle blood flow during anaesthesia and after the administration of vasoactive agents. Of the available techniques, blood flow measurements are limited to either microvascular flow (radioactive xenon, laser Doppler flowmetry) or total blood flow (radioactive microspheres, electromagnetic flowmetry, Doppler ultrasonography). None of the techniques currently available are able to fully assess the distribution of flow throughout the skeletal muscle. Near-infrared spectroscopy has the potential to assess the adequacy of oxygenation within muscles; however, this technique is not without limitations, and more work is required to assess its suitability. Understanding the limitations of these techniques is an important prerequisite to the critical evaluation of the information currently available on the effects of anaesthesia and vasoactive drugs on skeletal muscle blood flow.

Skeletal muscle blood flow in anaesthetized horses. Part II: effects of anaesthetics and vasoactive agents.

OBJECTIVE: This review aims at evaluating studies investigating the effects of anaesthesia on skeletal muscle blood flow and associated cardiovascular function in anaesthetized horses and discusses how the results of these studies contribute to our understanding of the pathogenesis and prevention of post-anaesthetic myopathy. DATABASE USED: Pubmed & personal files. CONCLUSION: There is little published information on the effects of anaesthesia on skeletal muscle blood flow in horses. Available reports predominantly refer to halothane and isoflurane. The effects of vasoactive drugs have mainly been studied in halothane-anaesthetized horses. The results of these studies support the importance of cardiac output in the maintenance of adequate arterial blood pressure, perfusion pressure and muscle blood flow. Adequate perfusion pressure appears to be important for overcoming the detrimental effects of high intra-compartmental pressure in dependent muscles and hydrostatic pressure in nondependent muscles.