Effects of remifentanil infusion regimens on cardiovascular function and responses to noxious stimulation in propofol-anesthetized cats

Objective-To evaluate the effects of 2 remifentanil infusion regimens on cardiovascular function and responses to nociceptive stimulation in propofol-anesthetized cats.Animals-8 adult cats.Procedures-On 2 occasions, cats received acepromazine followed by propofol (6 mg/kg then 0.3 mg/kg/min, IV) and a constant rate infusion (CRI) of remifentanil (0.2 or 0.3 mu g/kg/min,IV) for 90 minutes and underwent mechanical ventilation (phase I). After recording physiologic variables, an electrical stimulus (50 V; 50 Hz; 10 milliseconds) was applied to a forelimb to assess motor responses to nociceptive stimulation. After an interval (>= 10 days), the same cats were anesthetized via administration of acepromazine and a similar infusion regimen of propofol; the remifentanil infusion rate adjustments that were required to inhibit cardiovascular responses to ovariohysterectomy were recorded (phase II).Results-In phase I, heart rate and arterial pressure did not differ between remifentanil-treated groups. From 30 to 90 minutes, cats receiving 0.3 mu g of remifentanil/kg/min had no response to noxious stimulation. Purposeful movement was detected more frequently in cats receiving 0.2 mu g of remifentanil/kg/min. In phase II, the highest dosage (mean +/- SEM) of remifentanil that prevented cardiovascular responses was 0.23 +/- 0.01 mu g/kg/min. For all experiments, mean time from infusion cessation until standing ranged from 115 to 140 minutes.Conclusions and Clinical Relevance-Although the lower infusion rate of remifentanil allowed ovariohysterectomy to be performed, a CRI of 0.3 mu g/kg/min was necessary to prevent motor response to electrical stimulation in propofol-anesthetized cats. Recovery from anesthesia was prolonged with this technique.

Comparison of xylazine and medetomidine as premedicants for cats being anaesthetised with propofol-sevoflurane

The effects of premedicating cats with saline, xylazine or medetomidine before anaesthetising them with propofol-sevoflurane were compared. Twenty-four cats were randomly assigned to three groups of eight to receive either 0.25 ml of saline, 0.50 mg/kg of xylazine or 0.02 mg/kg of medetomidine intravenously, and anaesthesia was induced with propofol and maintained with sevoflurane. Medetomidine produced a greater reduction in the induction dose of propofol and fewer adverse postoperative effects than saline or xylazine. Hypoxaemia was observed after induction with propofol in the cats premedicated with saline and xylazine, but not in the cats given medetomidine. The cats treated with medetomidine and xylazine developed profound bradycardia. The blood pressure of the cats premedicated with saline and xylazine decreased, but the blood pressure of the cats premedicated with medetomidine was maintained. The cats premedicated with saline took longer to recover from anaesthesia than the other two groups.

EFEITOS DA INFUSAO CONTINUA DO PROPOFOL SOBRE A FUNCAO RENAL DO CAO. ESTUDO COMPARATIVO COM O PENTOBARBITAL SODICO

Little research has been done with propofol in relation to renal function. The aim of this study was to evaluate the effects of the continuous infusion of propofol on renal function in dogs. Sixteen dogs, previously anesthetized with pentobarbital sodium (30 mg.kg-1) for surgical preparation, catheterism and monitoring, were studied. The dogs were mechanically ventilated with air and received alcuronium (0.2 mg.kg-1 in bolus and 0.06 mg.kg-1 - maintenance). The following parameters were studied: heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), aortic blood flow (A(o)BF - by electromagnetic flowmeter installed in the ascending aortic), aortic vascular resistance index (A(o)VRI), renal plasma flow (ERPF - by para-aminohipurate clearance), glomerular filtration rate (GFR - by creatinine clearance), effective renal blood flow (ERBF = ERPF/1 - hematocrit), urinary volume (UV), renal vascular resistance (RVR = MAP.80/ERBF.10-3), urinary sodium excretion (UE(Na)), fractionated sodium excretion (FE(Na)), osmolar clearance (C(osm)) and free water clearance (C(H2O)). These parameters were studied at 15 (M1), 30 (M2), 45 (M3) and 60 (M4) min after beginning pentobarbital sodium infusion (5 mg.kg-1.h-1). The dogs were allocated into two groups of eight animals each: G1 (control-pentobarbital sodium) and G2 (propofol). In G1, pentobarbital was given at the four times studied. G2 dogs received the same treatment as G1 dogs at M1 and M2; infusion of pentobarbital was substituted by propofol (3 mg.kg-1 bolus, followed by 12 mg.kg-1.h-1 continuous infusion) at M3 and M4. Profile Analysis was used to analyze the results statistically. In G1 (pentobarbital), there was a significant increase in RVR (M1 < M4) and a decrease in ERPF and ERBF (M1 > M4). In G2 (propofol) there was only a significant increase in A(o)BF (M1 < M2 = M3). In comparison among groups, these was a significant alteration of FE(Na) at M3 (pentobarbital > propofol). It was observed that the continuous infusion of propofol in dogs, at the given doses, did not alter the basic variables of renal function and hemodynamics studied. We concluded that propofol can be one of the drugs of choice to provide base anesthesia in studies of renal function in dogs.

Comparacao da recuperacao de anestesia venosa com propofol e anestesia inalatoria com sevoflurano para laparoscopia ginecologica

Backgrounds and Objectives: Both continuous venous anesthesia with propofol and inhalational anesthesia with sevoflurane propitiate fast arousal with few side effects. The aim of this study was to compare the arousal and post anesthestic recovery times in patients submitted to these two agents. Methods: Forty three patient aged 18 to 50 years, physical status I or II, submitted to gynecological laparoscopy were distributed in two groups: G1 - propofol in continuous infusion of 115 μg.kg -1.min -1 and G2 sevoflurane. All the patients were pre-medicated with 7.5 mg midazolam, sufentanil 0.5 μg.kg -1, propofol 2 mg.kg -1, atracurium 0.5 mg.kg -1, N 2O in 50% of oxygen in a no-rebreathing system. The depth of the anesthesia and arousal time were assessed by the Bispectral index (BIS). The time between end of anesthesia and eye opening, time for command response and time for orientation were also evaluated. Results: The times recorded in minutes were: G1 - eye opening 8.2 ± 2.9, command response 8.6 ± 3.1, orientation 9.8 ± 3.4, recovery 31.6 ± 3.8; G2 - eye opening 4.5 ± 3, command response 4.9 ± 3.4, orientation 6.2 ± 3.4, recovery 66 ± 8. Except the recovery time, all the values were larger in G1. Conclusions: Both intravenous propofol or inhalational sevoflurane were considered excellent anesthetic techniques as to recovery time and recovery room discharge. Sevoflurane provided an earlier arousal with a longer recovery room stay as compared to propofol.

Evaluation of intraocular and partial CO2 pressure in dogs anesthetized with propofol

The effects of propofol on intraocular pressure (IOP) and end tidal CO2 (ETCO2) were studied because an elevation in the latter may alter IOP. Twenty dogs were divided into two groups (G1 and G2). G1 dogs were induced with 10 mg/kg (IV) of propofol followed by a 0.4 mg/kg/min continuous infusion of the same agent diluted in a 0.2% dextrose solution for 1 h. G(CAPS) 2 dogs served as the control group, where only dextrose solution was administered, under the same time intervals as in G1. Applanation tonometry (Tono-Pen) was used to determine IOP and ETCO2 as a method to determine partial CO2 pressure. Measurements were taken every 15 min for 1 h, with M1 occurring immediately before IV administration. IOP and ETCO2 were not statistically significant in either groups. Based on the results, it may be concluded that propofol does not alter IOP and ETCO2.

Comparison of xylazine and medotomidine as premedicants for cats being anaesthetised with propofol-sevoflurane

The effects of premedicating cats with saline, xylazine or medetomidine before anaesthetising them with propofol-sevoflurane were compared. Twenty-four cats were randomly assigned to three groups of eight to receive either 0.25 ml of saline, 0.50 mg/kg of xylazine or 0.02 mg/kg of medetomidine intravenously, and anaesthesia was induced with propofol and maintained with sevoflurane. Medetomidine produced a greater reduction in the induction dose of propofol and fewer adverse postoperative effects than saline or xylazine. Hypoxaemia was observed after induction with propofol in the cats premedicated with saline and xylazine, but not in the cats given medetomidine. The cats treated with medetomidine and xylazine developed profound bradycardia. The blood pressure of the cats premedicated with saline and xylazine decreased, but the blood pressure of the cats premedicated with medetomidine was maintained. The cats premedicated with saline took longer to recover from anaesthesia than the other two groups.

Efeitos de diferentes frações inspiradas de oxigênio sobre a dinâmica respiratória em cães submetidos à infusão contínua de propofol e mantidos em ventilação espontânea

The effects of several inspired oxygen fractions (FiO 2) on the respiratory dynamics in spontaneously breathing dogs submitted to continuous infusion of propofol were evaluated. Eight adult mongrel dogs were used. Each animal underwent five anesthesias, in each procedure the patient was allowed to breath a different FiO 2, thereby resulting in five groups, namely: G100 (FiO 2 = 1), G80 (FiO 2 = 0.8), G60 (FiO 2 =0.6), G40 (FiO 2 = 0.4), and G20 (FiO 2 = 0.21). To induce anesthesia, propofol was given until the animals allowed orotracheal intubation, followed by immediate continuous infusion of drug. The initial measurement (M0) was recorded thirty minutes after the infusion of propofol has begun. Additional recordings were performed at 15 minute intervals for 60 minutes (M15, M30, M45 and M60). Numeric data were submitted to Analysis of Variance followed by Tukey Test (p<0.05). We recorded significantly lower values of SpO 2 and SaO 2 at G20, whereas PaO 2 varied according to the changes in oxygen. Regarding PaCO 2, the mean of G100 was greater than G20 at M30. However, spontaneously breathing dogs anesthetized with propofol at the rate of 0.7mg/kg/min should not be provided with 100%, 80%, and 21% oxygen owing to the significant compromise of respiratory system.

Comparison of inflammatory cytokine profiles in plasma of patients undergoing otorhinological surgery with propofol or isoflurane anesthesia

Objective and design: The effects of anesthetics on cytokine release in patients without comorbidities who undergo minor surgery are not well defined. We compared inflammatory cytokine profiles in adult patients undergoing minimally invasive surgery who received isoflurane or propofol anesthesia. Methods: Thirty-four patients without comorbidities undergoing minor surgery were randomly assigned to receive an inhaled anesthetic (isoflurane; n = 16) or an intravenous anesthetic (propofol; n = 18). Blood samples were drawn before premedication and anesthesia (T1), 120 min after anesthesia induction (T2), and on the first post-operative day (T3). Plasma concentrations of interleukins (IL-) 1β, 6, 8, 10 and 12 and tumor necrosis factor (TNF)-α were measured using flow cytometry. Results: The pro-inflammatory cytokine IL-6 was increased in the isoflurane group at T2 and T3 compared to T1 (P < 0.01). In the propofol group, IL-6 and IL-8 were significantly increased at T3 compared to T1. However, there were no significant differences in cytokine concentrations between the isoflurane and propofol groups. Conclusion: An inflammatory response occurred earlier in patients who received an inhaled agent compared with an intravenous anesthetic, but no differences in plasma cytokine profiles were evident between isoflurane and propofol anesthesia in patients without comorbidities undergoing minimally invasive surgeries. © 2013 Springer Basel.

Determinação da taxa de infusão mínima de propofol e propofol associado a lidocaína em cães (Cannis familaris)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parâmetros ventilométricos, cardiovasculares, hematológicos e índice biespectral, em cães anestesiados com infusão contínua de propofol, associado ou não ao tramadol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anestesia de suínos com azaperona, midazolam e propofol em associação ao tramadol ou não

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anestesia total intravenosa em cães pela administração de propofol e butorfanol em infusão contínua: hemodinâmica, eletrocardiografia e índice biespectral

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de diferentes frações inspiradas de oxigênio em cães anestesiados com infusão contínua de propofol e rocurônio, mantidos em ventilação controlada a pressão

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da ventilação espontânea e ventilação mandatória intermitente sincronizada em cães anestesiados com infusão contínua de propofol

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo cardiorrespiratório comparativo da anestesia geral inalatória com o sevofluorano em cadela não-gestantes e no terço final da gestação, pré-tratados com acepromazina e propofol

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)