Pressão arterial sistólica em cães anestesiados: concordância entre mensurações por dois métodos não invasivos / Systolic blood pressure in anesthetized dogs: agreement between measurements by two noninvasive monitors

The oscillometric monitor is a noninvasive method used for measuring blood pressure in dogs and cats. Despite widely used, there is a large variability in the accuracy of oscillometric monitors, which may also be influenced by the location of the blood pressure cuff. The Doppler ultrasound is another non-invasive method that was shown to measure blood pressure with good accuracy and precision in small animals. The present study aimed to determine the agreement between systolic arterial pressure (SAP) measured by the Prolife P12 oscillometric monitor with 2 cuff locations and the Doppler ultrasound in anesthetized dogs. Dogs scheduled for routine anesthetic procedures were included in the study, which was carried out in 2 phases. In Phase 1, SAP values measured by the Doppler were compared with those measured by the Prolife P12 monitor with the cuff placed at the thoracic limb for both methods. In Phase 2, SAP values measured by the Doppler were compared with those measured by the Prolife P12 monitor, with the cuff placed at the thoracic limb for the Doppler and at the base of the tail for the P12. The cuff width corresponded to approximately 40% of limb or tail circumference. On all occasions, 3 consecutive measurements of SAP were recorded, followed by a single measurement of SAP by the P12, and then other 3 measurements were performed with the Doppler. The arithmetic mean of the 6 SAP measurements with the Doppler was compared with the SAP value measured by the P12 monitor (paired measurements). Agreement between SAP values measured by the Doppler and the P12 monitor was analyzed by the Bland Altman method for calculation of the bias (Doppler - P12) and standard deviation (SD) of the bias. The percentages of differences between the methods with an error ≤ 10 mmHg and ≤ 20 mmHg and Pearson's correlation coefficients were also calculated. Results were compared with the criteria from the American College of Veterinary Internal Medicine (ACVIM) for validation of noninvasive blood pressure methods. A total of 33 dogs were included in Phase 1 and 15 were included in Phase 2. During Phases 1 and 2, 179 and 87 paired measurements were recorded, respectively. Most of the measurements were recorded during normotension (SAP = 90-130 mmHg): 113/179 in Phase 1 and 52/87 in Phase 2. The bias (± SD) for Phases 1 and 2 were -2.7 ± 14.1 mmHg and 7.2 ± 25.8 mmHg. The percentages of differences ≤ 10 mmHg and ≤ 20 mmHg were: Phase 1, 61% and 83%; Phase 2, 41% and 70%. Correlation coefficients were 0.81 and 0.67 for Phases 1 and 2, respectively. According to the ACVIM criteria, maximum values accepted for bias are 10 ± 15 mmHg, the percentages of differences ≤ 10 mmHg and ≤ 20 mmHg should be ≥ 50% and ≥ 80%, respectively, and the correlation coefficient should be ≥ 0.9. When the blood pressure cuff was placed at the thoracic limb, SAP values measured by the P12 monitor met most of the ACVIM criteria, demonstrating good agreement with SAP values measured by the Doppler. The only requirement not met was the correlation coefficient which was 0.81 whereas the recommended is ≥ 0.9. Conversely, when the cuff was placed at the base of the tail, SAP values measured by the P12 monitor did not meet most of the ACVIM criteria indicating that, in anesthetized dogs, SAP measurements with the P12 monitor should be performed with the cuff placed at the thoracic limb. One limitation of this study was that most measurements fell in the normotensive range and the results should not be extrapolated for hypotensive and hypertensive conditions. In conclusion, the Prolife P12 oscillometric monitor demonstrated good agreement with SAP values measured by the Doppler and provides acceptable values in normotensive anesthetized dogs.(AU)

Monitoreo anestésico de la mezcla tiopental-propofol en hembras caninas durante la ovariohisterectomía / Anesthetic monitoring of the thiopental-propofol mixture in canine females during ovariohysterectomy / Monitorização anestésica que mistura tiopental-propofol em cadelas durante ovariohisterectomía

Resumen Objetivo: Monitorizar la fracción espiratoria final de CO2 (capnometría), saturación de oxígeno en la hemoglobina (pulsioxímetria) y la presión arterial media no invasiva (PAM) en perras sanas durante la ovariohisterectomía (OVH), en las cuales la anestesia fue inducida y mantenida con la mezcla Propofol-Tiopental (P-T). Materiales y métodos: Se practicó analítica prequirúrgica. La premedicación incluyo acepromacina, ketoprofeno y tramadol, la inducción anestésica se realizó con una mezcla en partes iguales de propofol 10 % y tiopental 2.5 %. La dosis de inducción se calculó en base al tiopental presente en cada cm3 de la mezcla, y fue de 3 mg / kg de tiopental / IV. Se dieron bolos a efecto de 1 mg /kg de tiopental presente en la mezcla para el mantenimiento. La capnometría, pulsioximetría y PAM se midieron cada cinco minutos utilizando un monitor multiparametrico. Los datos se analizaron con un estudio inferencial destinado a encontrar un intervalo de confianza para la media de saturación de oxígeno en la hemoglobina (SO2), fracción espiratoria final de CO2 (FEFCO2) y PAM, con una confianza del 95%. Resultados: La SO2 mantuvo un promedio de 97%, la PAM estuvo durante toda la intervención por encima de 60 mmHg, la FEFCO2 fue alta inicialmente >45mmHg, pero retorno a valores normales luego de 35 minutos. En promedio no se presentó hipoxemia o hipotensión, pero si hipercapnia leve al comienzo. Conclusión: Para las tres variables estudiadas la mezcla P-T fue segura. Se sugieren otros estudios con un monitoreo más amplio para determinar la seguridad hemodinámica y respiratoria.

Abstrac Objective: to monitor the final expiratory fraction of CO2 (capnometry), oxygen saturation in hemoglobin (pulse oximetry) and non-invasive mean arterial pressure (MAP) in healthy dogs during ovariohysterectomy (OVH), in which anesthesia was induced and maintained with the Propofol-Thiopental (PT) mixture. Materials and methods: Pre-surgical analysis was performed. The premedication included acepromazine, ketoprofen and tramadol, the anesthetic induction was performed with a mixture in equal parts of propofol 10% and thiopental 2.5%. The induction dose was calculated based on the thiopental present in each cm3 of the mixture, and was 3 mg / kg of thiopental / IV. Bowls were given for the effect of 1 mg / kg of thiopental present in the mixture for maintenance. Capnometry, pulse oximetry and MAP were measured every five minutes using a multiparametric monitor. The data were analyzed with an inferential study aimed at finding a confidence interval for the mean oxygen saturation in hemoglobin (SO2), final expiratory fraction of CO2 (FEFCO2) and PAM, with a confidence level of 95%. Results: SO2 maintained an average of 97%, MAP was throughout the intervention above 60 mmHg, FEFCO2 was initially high> 45mmHg, but return to normal values after 25 minutes. On average there was no hypoxia or hypotension, but mild hypercapnia at the beginning. Conclusion: For the three variables studied, the P-T mixture was safe. Studies with broader monitoring are suggested to determine hemodynamic and respiratory safety.

Resumo Objectivo: para monitorar a fracção final de CO2 expiratória (capnometria), saturação de oxigénio na hemoglobina (oximetria de pulso) e pressão arterial média de forma não invasiva (PAM) em cães saudáveis durante ovariohysterectomy (OVH), em que foi induzida a anestesia e mantida com a mistura Propofol-Thiopental (PT). Materiais e métodos: A análise pré-cirúrgica foi realizada. Acepromazina pré-medicação incluem, cetoprofeno e tramadol, a anestesia foi induzida com uma mistura de partes iguais de propofol e tiopental 10% 2,5%. A dose de indução foi calculada com base no tiopental presente em cada cm3 da mistura e foi de 3 mg / kg de tiopental / IV. As taças foram dadas para o efeito de 1 mg / kg de tiopental presente na mistura para manutenção. A capnometria, a oximetria de pulso e a PAM foram medidas a cada cinco minutos usando um monitor multiparamétrico. Os dados foram analisados com um estudo inferencial para encontrar um intervalo de confiança para a saturação média de oxigénio da hemoglobina (SO2), CO2 final (FEFCO2) e fracção expiratório PAM, com 95% de confiança. Resultados: O SO2 mantida uma média de 97%, MAP ao longo do processo era acima de 60 mmHg, a FEFCO2 foi elevada inicialmente> 45 mmHg, mas voltam ao normal após 25 minutos. Em média, não houve hipoxemia ou hipotensão, mas hipercapnia leve no início. Conclusão: Para as três variáveis ​​estudadas, a mistura P-T foi segura. Outros estudos com monitoramento mais amplo são sugeridos para determinar a segurança hemodinâmica e respiratória.

Efecto de dos maniobras cíclicas de reclutamiento alveolar sobre diversos parámetros de monitoreo microcirculatorio no invasivo en perros / Effect of two cyclical alveolar recruitment maneuvers on different parameters of non-invasive microcirculatory monitoring in dogs

RESUMEN Las maniobras de reclutamiento alveolar (MRA) son importantes para revertir la formación de atelectasias perioperatorias; no obstante, su realización está sujeta a cambios hemodinámicos significativos. El presente estudio evaluó el efecto de dos protocolos cíclicos de reclutamiento alveolar, mediante el incremento de la presión positiva al final de la espiración (PEEP), sobre tres parámetros de monitoreo, a saber: el gradiente de temperatura centro periférico (GT), el tiempo de relleno capilar (TRC) y la oximetría de pulso (SpO2), en 28 perros anestesiados. Los animales, se asignaron aleatoriamente en tres grupos, según la MRA a realizar, así: grupo 1, protocolo corto (PC) reclutado con PEEP de 10cmH2O; grupo 2, protocolo largo (PL) reclutado con PEEP de 20mH2O y grupo 3, protocolo control (PCo) ventilado con PEEP de 0cmH2O. Los parámetros de monitoreo fueron evaluados para cada maniobra en cuatro tiempos: T1 (basal en pre-anestesia), T2 (pre-reclutamiento), T3 (30min post-maniobra) y T4 (60min post-maniobra). En el T2, los valores de TRC presentaron una disminución significativa (p<0,05), respecto al tiempo basal. Posteriormente, en el T3, se evidenció una disminución estadísticamente significativa del GT para el grupo PC frente a los demás tratamientos; en el T4, el TRC presentó una disminución estadísticamente significativa (p<0,05) para el PL frente a los demás tratamientos. Se sugiere que, de acuerdo con los resultados encontrados, el protocolo de ventilación con incrementos de PEEP de hasta 20cmH2O es la MRA de elección, al no producir alteraciones de importancia clínica en los parámetros microcirculatorios evaluados.

ABSTRACT Alveolar recruitment maneuvers (ARM) are important in reversing the formation of perioperative atelectasis; however, its performance is subject to significant hemodynamic changes. The present study evaluated the effect of two cyclic alveolar recruitment protocols, by increasing positive end-expiratory pressure (PEEP), on three parameters of microcirculatory monitoring in 28 anesthetized dogs. Animals were randomly assigned to one of three groups, according to the ARM to be performed, thus: Group 1, short protocol (SP) recruited with PEEP of 10cmH2O; Group 2, long protocol (LP) recruited with PEEP of 20cmH2O; and Group 3, control protocol (CoP) ventilated with PEEP of 0cmH2O. For each maneuver, the central-peripheral temperature gradient (TG), capillary refill time (CRT) and pulse oximetry (SpO2) were evaluated, in four times namely: T1 (Pre-anesthesia), T2 (pre-recruitment), T3 (30 min post-maneuver) and T4 (60 min post-maneuver). In T2, CRT values showed a significant decrease (p<0.05), with respect to baseline time. Subsequently, in the T3, a significant statistical decrease of the TG for the SP group was evident compared to the other treatments; while in the T4 the CRT presented a significant decrease (p<0.05) for LP group versus the other treatments. It is suggested that under the conditions presented here, the protocol of ventilation with PEEP increments of up to 20cmH2O is the ARM of choice as it does not produce alterations of clinical importance in the microcirculatory parameters evaluated.

Bispectral index assessment in calves subjected to the continuous infusion of propofol combined with fentanyl administration / Indice biespectral em bezerros submetidos à infusão contínua de propofol associado ao fentanil

ABSTRACT: The aim of this study was to evaluate the bispectral index (BIS) effects in calves through continuous infusion of propofol with or without fentanyl. Eight Holstein male calves (ages from six to twelve months old) with an average weight of 123±18kg were used. All animals participated in both groups, always keeping a minimum interval of one week between the anesthetic procedures; the calves were randomly distributed between groups. Anesthesia was induced with an intravenous (IV) dose of propofol of 5mg kg-1 in control group (GP) or with propofol (4mg kg-1) associated with IV fentanyl 0.001mg kg-1(GF). All the calves were positioned in right lateral recumbency and were allowed to spontaneously breathe room air. Subsequently, the anesthesia was maintained by continuous infusion of propofol at the rate of 0.6mg kg-1 min-1 IV in GP, and associated with the infusion of fentanyl 0.001mg kg-1 hour-1 in GF. Measurements of BIS, signal quality index (SQI) and electromyography (EMG) were evaluated before anesthesia induction (TB), and at 15, 30, 45 and 60 minutes after the beginning of continuous drugs infusion (T15, T30, T45 and T60, respectively). The heart rate (HR), respiratory rate (f), end-tidal carbon dioxide tension (ETCO2) and recovery times were evaluated as well. No significant differences were observed between the groups in the BIS variables and the recovery time was longer in GF. Co-administration of propofol and fentanyl infusions, at the doses reported here, did not change the values of BIS in cattle, but delayed the recovery time.

RESUMO: O estudo teve por objetivo avaliar o índice biespectral (BIS) durante a infusão contínua de propofol associado ou não ao fentanil em bezerros. Foram utilizados oito animais machos entre seis e doze meses de idade, holandeses, com massa corporal média de 123±18kg. Todos os animais participaram de ambos os grupos, respeitando-se sempre um intervalo mínimo de uma semana entre uma anestesia e outra, sendo aleatoriamente distribuídos entre os grupos. A anestesia nos bezerros foi induzida com propofol na dose de 5mg kg-1; intravenoso (IV), grupo controle (GP) ou propofol 4mg kg-1 associado ao fentanil 0,001mg kg-1; IV, grupo fentanil (GF) e posicionados em decúbito lateral direito, onde permaneceram respirando espontaneamente ar ambiente. Ato contínuo, a manutenção anestésica foi realizada pela infusão contínua de propofol na taxa de 0,6mg kg-1 min-1; IV GP, associado ou não à infusão de fentanil 0.001mg kg-1 hora-1 GF. A mensuração das variáveis do BIS, índice de qualidade de sinal (IQS) eletromiografia (EMG), frequência cardíaca (FC), frequência respiratória (f) e dióxido de carbono ao final da expiração (ETCO2) foram avaliadas antes da indução anestésica no momento basal (MB), e 15, 30, 45 e 60 minutos após o início da infusão contínua dos fármacos (M15, M30, M45 e M60, respectivamente); o tempo de recuperação também foi avaliado. Não foram observadas diferenças significativas entre os grupos nas variáveis do BIS e o tempo de recuperação foi maior no GF. A co-administração das infusões de propofol e fentanil, nas doses utilizadas nesse estudo, não alterou os valores do BIS em bezerros, porém, prolongou o tempo de recuperação.