The Edwards Acumen IQ system using peripheral arterial catheter-based waveforms to estimate cardiac output is not accurate as compared to thermodilution in dogs.

OBJECTIVE: To assess the agreement between cardiac output (CO) estimated via evaluation of the arterial pressure waveform by a novel monitoring system (Edwards Acumen IQ sensor and HemoSphere Advanced Monitor Platform [HS-IQ]; Edwards LifeSciences) and measured by thermodilution (TD) in anesthetized, normovolemic, and hypovolemic dogs. To assess the agreement between the HS-IQ CO measurements in the radial artery and dorsal metatarsal artery. ANIMALS: 8 purpose-bred Beagles. METHODS: Dogs were placed under general anesthesia. CO was measured via TD and via the HS-IQ at radial and dorsal metatarsal arterial catheters. CO measurements were obtained at 4 time points including normovolemic and multiple hypovolemic states. Paired measurements of CO were evaluated via the method of Bland and Altman with acceptable limits of agreement (LOA) defined as < 30%. RESULTS: A total of 24 (dorsal metatarsal) and 21 (radial) paired measurements were collected in 8 dogs. The overall bias (CI) for comparison of TD to radial arterial HS-IQ CO measurements was -0.09 L/min. LOA and proportional LOA were -2.66 to 2.49 L/min and -140.72% to 104.94%. The overall bias (CI) for comparison of TD to dorsal metatarsal arterial HS-IQ CO measurements was -0.26 L/min. LOA and proportional LOA were -2.76 to 2.24 L/min and -135.96% to 93.25%. The overall proportional error for radial arterial was -17.9% and for dorsal metatarsal was -21.4%. CLINICAL RELEVANCE: CO measurements with the HS-IQ were easy to obtain but did not produce results within a clinically acceptable range for either measurement site, with a very wide LOA. The CO estimations from the HS-IQ are not appropriate for clinical use at this time.

Accuracy and trending capability of haemoglobin measurement by noninvasive pulse co-oximetry in anaesthetized horses.

OBJECTIVE: To assess the accuracy and trending capability of continuous measurement of haemoglobin concentration [Hb], haemoglobin oxygen saturation (SaO2) and oxygen content (CaO2) measured by the Masimo Radical-7 pulse co-oximeter in horses undergoing inhalational anaesthesia. STUDY DESIGN: Prospective observational clinical study. ANIMALS: A group of 23 anaesthetized adult horses. METHODS: In 23 healthy adult horses undergoing elective surgical procedures, paired measurements of pulse co-oximetry-based haemoglobin concentration (SpHb), SaO2 (SpO2), and CaO2 (SpOC) and simultaneous arterial blood samples were collected at multiple time points throughout anaesthesia. The arterial samples were analysed by a laboratory co-oximeter for total haemoglobin (tHb), SaO2 and manually calculated CaO2. Bland-Altman plots, linear regression analysis, error grid analysis, four-quadrant plot and Critchley polar plot were used to assess the accuracy and trending capability of the pulse co-oximeter. Data are presented as mean differences and 95% limits of agreement (LoA). RESULTS: In 101 data pairs analysed, the pulse co-oximeter slightly underestimated tHb (bias 0.06 g dL-1; LoA -1.0 to 1.2 g dL-1), SaO2 (bias 1.4%; LoA -2.0% to 4.8%), and CaO2 (bias 0.3 mL dL-1; LoA -2.1 to 2.7 mL dL-1). Zone A of the error grid encompassed 99% of data pairs for SpHb. Perfusion index (PI) ≥ 1% was recorded in 58/101 and PI < 1% in 43/101. The concordance rate for consecutive changes in SpHb and tHb with PI ≥ 1% and < 1% was 80% and 91% with four-quadrant plot, and 45.8% and 66.6% with Critchley polar plot. CONCLUSIONS: Pulse co-oximetry has acceptable accuracy for the values measured, even with low PI, whereas its trending ability requires further investigation in those horses with a higher [Hb] variation during anaesthesia.

Transoperative glycemia in pets: validating old ones, and presenting lip mucosa as new sampling site.

The aim of our study was to investigate the viability and validity of blood sampling from the upper lip mucosa in healthy dogs and cats for monitoring transoperative glycemia and compare the results with those obtained from samples taken from previously described blood sampling sites for determination of glycemia using a glucose meter. Blood glucose (BG) levels were determined in samples taken from the upper lip mucosa of 24 dogs and 31 cats undergoing neutering or spaying surgeries. These values were compared to those of samples obtained from other sites previously described for capillary blood glucose monitoring (marginal ear vein, carpal pad in dogs, metacarpal pad in cats) using a glucose meter. Additionally, BG from peripheral venous blood was determined using a glucose meter, and the gold standard enzymatic colorimetric assay. The clinical reliability of BG values taken from lip mucosa and from all the other BG values measured by the glucose meter was evaluated using the error grid analysis modified by Parkes et al (2000). The upper lip mucosa was an easily accessible site for the obtainment of appropriate blood samples, and glucose levels read in these samples correlated positively with glycemic values read in blood samples from all other sites in dogs and cats. All BG made using glucose meters taken from all sites were within the clinically acceptable range when compared with enzymatic colorimetric assay (gold standard), and were analytically accurate according to the error grid (zones A and B). All blood sampling sites described in this work can be used to assess transoperative glycemia. The upper lip mucosa is a viable blood sampling site for precise monitoring of transoperative glycemia in healthy dogs and cats and shows promise for alternative blood glucose monitoring.

Appraisal of the 'penumbra effect' using lingual pulse oximetry in anaesthetized dogs and cats.

OBJECTIVE: Factors described as contributors to the 'penumbra effect' in relation to pulse oximetry include optical shunting, circulatory anastomoses and probe parallelity. This study aimed to clarify the main underlying mechanism involved. STUDY DESIGN: Prospective clinical trial. ANIMALS: A total of 30 dogs and 15 cats (client-owned). METHODS: In anaesthetized dogs and cats, a pulse oximeter probe was placed on the tongue to measure haemoglobin oxygen saturation (SpO2) and perfusion index. In 15 dogs, the probe was positioned at the root (baseline) of the tongue, then at 0.5 and 1 cm rostral to it, to investigate the effect of circulatory anastomoses on SpO2 values. In cats (which do not have lingual arteriovenous anastomoses), the probe was positioned at the root and apex of the tongue. To assess the effect of probe parallelity on SpO2 values in dogs, two lines were drawn parallel to the planes of the light-emitting diode and the detector surfaces and the intersection angle calculated using ImageMeter Pro, Google Play. In a further 15 dogs, the probe was placed at the tongue edge (0% optical shunt), with 50% optical shunt, then with the 50% optical shunt shielded. Data were analysed using Friedman's test, Student t test and Pearson's correlation coefficient (p < 0.05). RESULTS: In dogs, SpO2 values were significantly higher at 1.0 cm than at baseline (p < 0.0001). In cats, there were no significant differences in SpO2 values at each location. There was no significant difference in SpO2 between 0% and 50% optical shunt in dogs. SpO2 had a moderate negative correlation with tongue thickness and negligible correlation with intersection angle. CONCLUSIONS AND CLINICAL RELEVANCE: Circulatory anastomoses are probably responsible for observed changes in SpO2 as the probe is placed towards an extremity, rather than optical shunting or probe parallelity.

Near-infrared imaging and optical coherence tomography for intraoperative visualization of tumors.

Surgical excision is the foundation of treatment for early-stage solid tumors in man and companion animals. Complete excision with appropriate margins of surrounding tumor-free tissue is crucial to survival. Intraoperative imaging allows real-time visualization of tumors, assessment of surgical margins, and, potentially, lymph nodes and satellite metastatic lesions, allowing surgeons to perform complete tumor resections while sparing surrounding vital anatomic structures. This Review will focus on the use of near-infrared imaging and optical coherence tomography for intraoperative tumor visualization.

Survey on conduct of anaesthetic monitoring in small animal practice in the UK.

BACKGROUND: An online survey was used to investigate current anaesthetic monitoring practices and the confidence level of personnel monitoring anaesthetics in small animal practices within the UK. METHODS: Veterinary surgeons (VSs), registered veterinary nurses (RVNs) and student veterinary nurses (SVNs) working in the UK were invited to participate in an anonymous, internet-based survey. To gather data, the questions used free text, multiple choice or scales measuring respondent attitude or opinion. No questions were mandatory and data were analysed with descriptive statistics or inductive thematic analysis. RESULTS: 524 valid surveys were completed and included in the data analysis (VS n=136, RVN n=307, SVN n=81). The results indicated mainly RVNs perform pre-anaesthetic monitoring equipment checks, set-up the monitoring equipment and monitor anaesthesia and are more confident than VSs monitoring anaesthetics. VSs, RVNs and SVNs were all recognised to interpret and address changes in parameters monitored. Critical tasks pertaining to anaesthetic monitoring are being performed by personnel other than a VS, RVN or SVN. Respondents recognised the importance of monitoring in relation to patient outcome; however, a considerable proportion of respondents indicated that improving standards of monitoring was not a priority in their practice. Most respondents felt that standards of monitoring could be improved and that financial constraints were the major factor limiting improvement. Most respondents felt they would benefit from further training in anaesthetic monitoring. CONCLUSION: Variability exists in how anaesthetic monitoring is conducted. Workplace pressures afflicting veterinary staff can influence the conduct of anaesthetic monitoring and initiating change within a veterinary practice can be difficult.

Clinical monitoring of cardiac output assessed by transoesophageal echocardiography in anaesthetised dogs: a comparison with the thermodilution technique.

BACKGROUND: Cardiac output (CO) is an important haemodynamic parameter to monitor in patients during surgery. However, the majority of the techniques for measuring CO have a limited application in veterinary practice due to their invasive approach and associated complexity and risks. Transoesophageal echocardiography (TEE) is a technique used to monitor cardiac function in human patients during surgical procedures and allows CO to be measured non-invasively. This prospective clinical study aimed to compare the transoesophageal echocardiography using a transgastric view of the left ventricular outflow tract (LVOT) and the thermodilution (TD) technique for the assessment of CO during mean arterial pressure of 65-80 mmHg (normotension) and <65 mmHg (hypotension) in dogs undergoing elective surgery. Eight dogs were pre-medicated with acepromazine (0.05 mg/kg, IM), tramadol (4 mg/kg, IM) and atropine (0.03 mg/kg, IM), followed by anaesthetic induction with propofol (3-5 mg/kg IV) and maintenance with isoflurane associated with a continuous infusion rate of fentanyl (bolus of 3 µg/kg followed by 0.3 µg/kg/min). The CO was measured by TEE (COTEE) and TD (COTD) at the end of expiration during normotension and hypotension (induced by isoflurane). RESULTS: There was a strong positive correlation between COTEE and COTD ​​(r = 0.925; P < 0.0001). The bias between COTD and COTEE was 0.14 ± 0.29 L/min (limits of agreement, -0.44 to 0.72 L/min). The percentage error of CO measured by the two methods was 12.32%. In addition, a strong positive correlation was found between COTEE and COTD during normotension (r = 0.995; P < 0.0001) and hypotension (r = 0.78; P = 0.0223). CONCLUSIONS: The results of this study indicated that the transgastric view of the LVOT by TEE was a minimally invasive alternative to clinically monitoring CO in dogs during anaesthesia. However, during hypotension, the CO obtained by TEE was less reliable, although still acceptable.

Basics of monitoring equipment.

Monitoring equipment has become reliable and affordable for use in general veterinary practice. This article provides a guide to technology, troubleshooting, and obtaining quality data using 4 non-invasive techniques that are commonly used in practice. Pulse oximetry estimates oxygen saturation of hemoglobin in arterial blood, capnography measures the carbon dioxide content of inspired and expired gas, and either Doppler shift detection or oscillometry can be used to measure blood pressure. These useful non-invasive techniques all rely on adequate perfusion of the tissues for optimum function.

Éléments fondamentaux de l'équipement de monitorage. L'équipement de monitorage est devenu fiable et abordable pour utilisation dans la pratique vétérinaire générale. Le présent article présente un guide sur la technologie, le diagnostic de panne et l'obtention de données de qualité en utilisant quatre techniques non invasives qui sont communément utilisées en pratique. L'oxymétrie pulsée estime la saturation en oxygène de l'hémoglobine dans le sang artériel, la capnographie mesure le contenu en gaz carbonique du gaz inspiré et expiré et la détection du déplacement Doppler ou l'oscillométrie peut être utilisée pour mesurer la pression artérielle. Ces techniques non invasives s'appuient toutes sur une perfusion adéquate des tissus pour une fonction optimale.(Traduit par Isabelle Vallières).

Nasopharyngeal temperature measurement in sheep during general anesthesia.

The aim of this study was to compare nasopharyngeal and esophageal temperature measurements in anesthetized sheep with a range of fresh gas flows (1 to 6 L/min) through the breathing system. Data were compared using a Bland-Altman plot and correlation coefficients, and error measures were calculated. One hundred and ninety-five sets of data were collected from 20 sheep weighing 41 kg (31 to 51.5 kg). The bias (95% limit of agreement), correlation coefficient, and absolute error for nasopharyngeal compared to esophageal temperature were 0.04°C (-0.77°C to 0.85°C), 0.92, and 0.29°C ± 0.29°C, respectively. The percentage of nasopharyngeal readings within 0.5°C of the esophageal temperature was 77.44%. The error did not significantly increase with increasing fresh gas flow. Nasopharyngeal temperature measurement is suitable for estimation of esophageal temperature during general anesthesia of sheep when the fresh gas flow through the breathing system is between 1 and 6 L/min.

L'objectif de la présente étude était de comparer les mesures des températures nasopharyngiennes et oesophagiennes chez des moutons anesthésiés avec une variation du flux de gaz frais (1 à 6 L/min) à travers le système respiratoire. Les données ont été comparées à l'aide d'un graphique de Bland-Altman et des coefficients de corrélation, et les erreurs de mesure ont été calculées. Cent quatre-vingt-quinze paires de données ont été obtenues de 20 moutons pesant en moyenne 41 kg (31 à 51,5 kg). Le biais (limite d'accord de 95 %), le coefficient de corrélation, et l'erreur absolue de la température nasopharngienne comparée à la température oesophagienne étaient 0,04 °C (−0,77 °C à 0,85 °C), 0,92, et 0,29 °C ± 0,29 °C, respectivement. Le pourcentage de lecture de température nasopharyngienne à l'intérieur d'un écart de 0,5 °C de la température oesophagienne était de 77,44 %. L'erreur n'a pas augmenté de manière significative avec l'augmentation du flux de gaz frais. La mesure de la température nasopharyngienne est appropriée pour estimer la température oesophagienne lors de l'anesthésie générale de moutons lorsque le flux de gaz frais à travers le système respiratoire se situe entre 1 et 6 L/min.(Traduit par Docteur Serge Messier).

Impact of Stroke Therapy Academic Industry Roundtable (STAIR) Guidelines on Peri-Anesthesia Care for Rat Models of Stroke: A Meta-Analysis Comparing the Years 2005 and 2015.

Numerous studies using rats in stroke models have failed to translate into successful clinical trials in humans. The Stroke Therapy Academic Industry Roundtable (STAIR) has produced guidelines on the rodent stroke model for preclinical trials in order to promote the successful translation of animal to human studies. These guidelines also underline the importance of anaesthetic and monitoring techniques. The aim of this literature review is to document whether anaesthesia protocols (i.e., choice of agents, mode of ventilation, physiological support and monitoring) have been amended since the publication of the STAIR guidelines in 2009. A number of articles describing the use of a stroke model in adult rats from the years 2005 and 2015 were randomly selected from the PubMed database and analysed for the following parameters: country where the study was performed, strain of rats used, technique of stroke induction, anaesthetic agent for induction and maintenance, mode of intubation and ventilation, monitoring techniques, control of body temperature, vascular accesses, and administration of intravenous fluids and analgesics. For each parameter (stroke, induction, maintenance, monitoring), exact chi-square tests were used to determine whether or not proportions were significantly different across year and p values were corrected for multiple comparisons. An exact p-test was used for each parameter to compare the frequency distribution of each value followed by a Bonferroni test. The level of significant set at < 0.05. Results show that there were very few differences in the anaesthetic and monitoring techniques used between 2005 and 2015. In 2015, significantly more studies were performed in China and significantly fewer studies used isoflurane and nitrous oxide. The most striking finding is that the vast majority of all the studies from both 2005 and 2015 did not report the use of ventilation; measurement of blood gases, end-tidal carbon dioxide concentration, or blood pressure; or administration of intravenous fluids or analgesics. The review of articles published in 2015 showed that the STAIR guidelines appear to have had no effect on the anaesthetic and monitoring techniques in rats undergoing experimental stroke induction, despite the publication of said guidelines in 2009.

Comparison of computed tomographic angiography and intraoperative mesenteric portovenography for extrahepatic portosystemic shunts.

OBJECTIVES: Comparison of intra-operative mesenteric portovenography and computed tomographic angiography for the documentation of the portal vasculature in patients with single extrahepatic portosystemic shunts. METHODS: Retrospective study of patients with extrahepatic portosystemic shunts that underwent preoperative computed tomographic angiography and intra-operative mesenteric portography. Studies were compared for identification of the intra- and extrahepatic portal vasculature. RESULTS: Computed tomographic angiography demonstrated all four portal vein tributaries and sub-tributaries. Intra-operative mesenteric portography inconsistently demonstrated the cranial mesenteric vein, the gastroduodenal vein (12 of 49 dogs and 0 of 10 cats), splenic vein (46 of 49 dogs and 8 of 10 cats) and caudal mesenteric vein (3 of 49 dogs and 2 of 10 cats). Computed tomographic angiography showed the intrahepatic portal vein with shunts emanating from the left gastric vein, splenocaval shunts or shunts involving the left colic vein. It showed intrahepatic portal branching in 5 of 12 patients with shunts involving the right gastric vein. Intra-operative mesenteric portography showed the intrahepatic portal vein in 29 of 59 patients but was outperformed by computed tomographic angiography in all cases except those patients with a shunt involving the right gastric vein. CLINICAL SIGNIFICANCE: In cases that have undergone diagnostic preoperative computed tomographic angiography there is no indication for diagnostic intra-operative mesenteric portovenography before ligation. In contrast, portovenography performed "after" temporary full ligation of the shunt provides clinical useful information and might be considered an integral investigation during shunt attenuation surgery.

Differential effects of propofol and isoflurane on the relationship between EEG Narcotrend index and clinical stages of anaesthetic depth in sheep undergoing experimental cardiac surgery.

The electroencephalogram (EEG) Narcotrend index (NI) has been shown to improve anaesthetic depth monitoring in isoflurane-anaesthetised sheep. Data obtained from 13 anaesthetised juvenile female sheep were analysed retrospectively in order to assess the relationship between clinical stages of anaesthesia (CS) and NI during both propofol and isoflurane anaesthesia. Polynomial regression analysis revealed no significant association between CS and NI for propofol (R = 0.374, R(2) = 0.140, P = 0.403) but for isoflurane anaesthesia (R = 0.548, R(2) = 0.301, P = 0.010) there was a significant relationship. Furthermore, a strong correlation existed between end-tidal isoflurane concentration (ISOET) and CS (r = -0.463, P = 0.008). A combination of assessment of clinical signs and analogous EEG patterns is recommended during propofol anaesthesia.

Comparison of invasive and noninvasive blood pressure measurements in anaesthetized horses using the Surgivet V9203.

OBJECTIVES: To determine the bias and precision of noninvasive versus invasive blood pressure measurements obtained using the Surgivet V9203 in anaesthetized horses; to compare these with the current American College of Veterinary Internal Medicine Hypertension Consensus Panel (AHCP) and Veterinary Blood Pressure Society (VBPS) recommendations; and to investigate whether noninvasive blood pressure monitoring could be a clinically useful alternative to invasive blood pressure monitoring in anaesthetized horses. STUDY DESIGN: Prospective clinical study in a university teaching hospital. ANIMALS: Forty-three horses with an average weight of 485 ± 90 kg and a mean age of 103.4 ± 57.6 months. METHODS: Arterial blood pressure (BP) was measured noninvasively (NIBP) via a cuff placed over either the ventral coccygeal artery or the metacarpal artery, and invasively (IBP) via a catheter in either the facial artery or the metatarsal artery. A total of 143 paired readings were obtained. Comparison of measurements was carried out using the Bland-Altman method. Analysis was performed using all the data, and these data were subdivided according to the position of the horse and the magnitude of the pressure measurement. To determine the accuracy of the noninvasive measurements, the calculated precision and bias were compared with AHCP and VBPS guidelines. RESULTS: For all categories, NIBP measurements were generally lower than IBP measurements. For pooled data, the bias and precision for systolic arterial pressure (SAP) were 6.8 and 11.9 mmHg; for mean arterial pressure (MAP) the values were 1.9 and 10.0 mmHg; and for diastolic arterial pressure (DAP) they were 5.7 and 10.8 mmHg. The bias and precision for MAP and DAP measurements were within the recommended guidelines defined by the AHCP and VBPS. CONCLUSIONS AND CLINICAL RELEVANCE: These results suggests that systolic, mean and diastolic NIBP measured using the Surgivet V9203 are a clinically acceptable alternative to IBP measurements in anaesthetized horses undergoing routine elective surgeries.

Surgery in Amphibians.

Amphibian surgery has been especially described in research. Since the last decade, interest for captive amphibians has increased, so have the indications for surgical intervention. Clinicians should not hesitate to advocate such manipulations. Amphibian surgeries have no overwhelming obstacles. These patients heal well and tolerate blood loss more than higher vertebrates. Most procedures described in reptiles (mostly lizards) can be undertaken in most amphibians if equipment can be matched to the patients' size. In general, the most difficult aspect would be the provision of adequate anesthesia.

Assessment of Fluid Balance and the Approach to Fluid Therapy in the Perioperative Patient.

Perioperative patients can be highly dynamic and have various metabolic, physiologic, and organ system derangements that necessitate smart monitoring strategies and careful fluid therapy. The interplay between changing patient status, therapeutic interventions, and patient response makes effective monitoring crucial to successful treatment. Monitoring the perioperative patient and an approach to fluid therapy are discussed in this text.

Optimal cutoff points of entropy indices for use in predicting responses elicited during determination of minimum alveolar concentration of sevoflurane in dogs.

OBJECTIVE: To investigate values of spectral indices for use in predicting responses in dogs during determination of minimum alveolar concentration (MAC) of sevoflurane. ANIMALS: 15 healthy German Shepherd Dogs. PROCEDURES :Sevoflurane MAC was determined by use of tail clamping. Entropy indices consisting of response entropy and state entropy were recorded during MAC determination. Optimal cutoff points of response entropy and state entropy for use in predicting responses to tail clamping were analyzed with multiple logistic regression. RESULTS: Sevoflurane MAC ranged from 1.8% to 2.6% (mean ± SD, 2.2 ± 0.3%). Response entropy and state entropy were significantly higher during positive responses to tail clamping (88 ± 2 and 76 ± 2, respectively) than during negative responses to tail clamping (63 ± 3 and 52 ± 3, respectively). The difference between the 2 entropy indices did not differ between positive (11 ± 1) and negative (13 ± 1) responses to tail clamping. Response entropy and state entropy served as independent predictors of a positive response, with areas under the curve for receiver operating characteristic curves 0.810 (95% confidence interval, 0.716 to 0.903) and 0.828 (95% confidence interval, 0.741 to 0.916), respectively. Optimal cutoff points to predict a positive response were 75 for response entropy and 65 for state entropy, which corresponded to mean ± SD ORs of 25.2 ± 15.6 and 14.9 ± 7.9, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Response entropy and state entropy were good predictors of responses to tail clamping elicited during determination of sevoflurane MAC in healthy dogs.

Evaluation of an oesophageal Doppler device for monitoring cardiac output in anaesthetised healthy normotensive dogs.

OBJECTIVES: To compare cardiac output measured by oesophageal Doppler and by thermodilution monitoring and to correlate the Doppler cardiac output-generated minute distance with thermodilution cardiac output in healthy anaesthetised beagle dogs. MATERIALS AND METHODS: Prospective experimental study. Six healthy adult beagle dogs were pre-medicated with intramuscular acepromazine (0 · 05 mg/kg) and methadone (0 · 3 mg/kg). Anaesthesia was induced with intravenous propofol (dose-effect) and maintained with isoflurane in oxygen. Simultaneously, a constant rate infusion of dopamine (3 µg/kg/minute) was administered to the dogs to prevent hypotension. The minute distance, Doppler and thermodilution cardiac outputs were assessed at three different end-tidal concentrations of isoflurane (1 · 0, 1 · 3 and 2 · 0%). RESULTS: Correlation between Doppler and thermodilution cardiac output (r(2) = 0 · 582) and between minute distance and thermodilution cardiac output (r(2) = 0 · 658) were moderately good, but the limits of agreement between Doppler and thermodilution cardiac outputs were above the recommended values (±39%, for a recommended value up to 30%). CLINICAL SIGNIFICANCE: Doppler and minute distance cannot be considered as an alternative method to thermodilution to monitor cardiac output in the healthy anaesthetised dog.

Bispectral index in calves anesthetized with xylazine, midazolam, ketamine, isoflurane and subjected to continuous rate infusion of lidocaine.

PURPOSE: To assess the bispectral index (BIS) and recovery in calves anesthetized with xylazine, midazolam, ketamine and isoflurane and subjected to CRI of lidocaine. METHODS: Xilazine was administered followed by ketamine and midazolam, orotracheal intubation and maintenance on isoflurane using mechanical ventilation. Lidocaine (2 mg kg(-1) bolus) or saline (0.9%) was administered i.v. followed by a CRI (100 µg kg(-1) minute(-1)) of lidocaine (L) or saline (C). Were recorded BIS, heart rate (HR), mean arterial pressure (MAP) and rectal temperature (RT) before administration of premedication (TB) and 15 minutes after (TX), before administering lidocaine (T0) and 20, 40, 60 and 80 minutes after the start of the CRI . Time do sternal recumbency (SRE) and standing (ST) and plasma lidocaine concentration also evaluated. RESULTS: In both treatments BIS decreased significantly at all times compared to TB. TX was higher than the subsequent times. HR decreased from baseline at all times and decreased from T40 in L compared to C. SRE was higher in L compared to C. CONCLUSIONS: Bispectral index values were consistent with the degree of hypnosis of the animals. Lidocaine did not potentiate isoflurane anesthesia assessed by BIS in unstimulated calves anesthetized with constant E´Iso. Lidocaine increased the time to sternal recumbency.

Bispectral index in calves anesthetized with xylazine, midazolam, ketamine, isoflurane and subjected to continuous rate infusion of lidocaine

PURPOSE: To assess the bispectral index (BIS) and recovery in calves anesthetized with xylazine, midazolam, ketamine and isoflurane and subjected to CRI of lidocaine. METHODS: Xilazine was administered followed by ketamine and midazolam, orotracheal intubation and maintenance on isoflurane using mechanical ventilation. Lidocaine (2 mg kg-1 bolus) or saline (0.9%) was administered IV followed by a CRI (100 µg kg-1 minute-1) of lidocaine (L) or saline (C). Were recorded BIS, heart rate (HR), mean arterial pressure (MAP) and rectal temperature (RT) before administration of premedication (TB) and 15 minutes after (TX), before administering lidocaine (T0) and 20, 40, 60 and 80 minutes after the start of the CRI . Time do sternal recumbency (SRE) and standing (ST) and plasma lidocaine concentration also evaluated. RESULTS: In both treatments BIS decreased significantly at all times compared to TB. TX was higher than the subsequent times. HR decreased from baseline at all times and decreased from T40 in L compared to C. SRE was higher in L compared to C. CONCLUSIONS: Bispectral index values were consistent with the degree of hypnosis of the animals. Lidocaine did not potentiate isoflurane anesthesia assessed by BIS in unstimulated calves anesthetized with constant E´Iso. Lidocaine increased the time to sternal recumbency. .