Propofol In Rabbits Research Articles

Sevoflurane reduces the cardiac toxicity of bupivacaine compared with propofol in rabbits: an experimental study using early electrocardiographic detection and measurement of toxic plasma concentration

Sevoflurane reduces the cardiac toxicity of bupivacaine compared with propofol in rabbits: an experimental study using early electrocardiographic detection and measurement of toxic plasma concentration

Comparison of time to loss of consciousness and maintenance of anesthesia following intraosseous and intravenous administration of propofol in rabbits

To compare time to loss of consciousness (LOC) and effective maintenance of anesthesia following intraosseous (IO) and IV administration of propofol in rabbits. Evaluation study. 24 New Zealand White rabbits. Rabbits were selected to receive IO (n = 6) or IV (6) bolus administration of 1% propofol (12.5 mg/kg [5.67 mg/lb]) only or an identical bolus of propofol IO (6) or IV (6) followed by a constant rate infusion (CRI; 1 mg/kg/min [0.45 mg/lb/min]) by the same route for 30 minutes. Physiologic variables were monitored at predetermined time points; time to LOC and durations of anesthesia and recovery were recorded. Following IO and IV bolus administration, mean time to LOC was 11.50 and 7.83 seconds, respectively; changes in heart rate, respiratory rate, oxygen saturation (as measured by pulse oximetry), and mean arterial blood pressure values were evident, but findings did not differ between groups. For the IO- and IV-CRI groups, propofol-associated changes in heart rate, oxygen saturation, and mean arterial blood pressure values were similar, and although mean arterial blood pressure decreased significantly from baseline, values remained > 60 mm Hg; respiratory rate decreased significantly during CRI in both groups, but remained higher in the IO-CRI group. Anesthesia and recovery time did not differ between the IO- and IV-CRI groups. In all evaluated aspects of anesthesia, IO administration of propofol was as effective as IV administration in rabbits. Results suggested that total IO anesthesia can be performed in rabbits with limited vascular access.

Lipid metabolism disturbances and AMPK activation in prolonged propofol-sedated rabbits under mechanical ventilation

To explore the mechanisms underlying the propofol infusion syndrome (PRIS), a potentially fatal complication during prolonged propofol infusion. Male rabbits under mechanical ventilation through endotracheal intubation were divided into 3 groups (n=6 for each) that were sedated with 1% propofol (Group P), isoflurane (Group I) or isoflurane while receiving 10% intralipid (Group II), respectively. Blood biochemical parameters were collected at 0, 6, 12, 18, 24 and 30-36 h after the initiation of treatments. The hearts were removed out immediately after the experiments, and the level of tumor necrosis factor (TNF)-α in the hearts were studied using immunohistochemistry. AMP-activated protein kinase (AMPK) and phospho-AMPK in the hearts were assessed using Western blotting. The mortality rate was 50% in Group P, and 0% in Groups I and II. The serum lipids and liver function indices in Group P were significantly increased, but moderately increased in Group II. Significant decreases in these indices were found in Groups I. All the groups showed dramatically increased release of creatine kinase (CK). Intense positive staining of TNF-α was found in all the heart samples in Group P, but only weak and neglectful staining was found in the hearts from Group II and Group I, respectively. AMPK phosphorylation was significantly increased in the hearts of Group P. Continuous infusion of large dose of propofol in rabbits undergoing prolonged mechanical ventilation causes hyperlipidemia, liver dysfunction, increased CK levels, AMPK activation and myocardial injury. The imbalance between energy demand and utilization may contribute to PRIS.

Influence of Time of Day on Propofol Pharmacokinetics and Pharmacodynamics in Rabbits

This study evaluates the administration time-of-day effects on propofol pharmacokinetics and sedative response in rabbits. Nine rabbits were sedated with 5 mg/kg propofol at three local clock times: 10:00, 16:00, and 22:00 h. Each rabbit served as its own control by being given a single infusion at the three different times of day on three separate occasions. Ten arterial blood samples were collected during each clock-time experiment for propofol assay. A two-compartment model was used to describe propofol pharmacokinetics, and the pedal withdrawal reflex was used as the sedation pharmacodynamic response. The categorical data comprising the presence or absence of pedal withdrawal reflex was described by a logistic model. The typical volume of the central compartment equaled 7.67 L and depended on rabbit body weight. The elimination rate constant depended on drug administration time; it was lowest at 10:00 h, highest at 16:00 h, and intermediate at 22:00 h. Delay of the anesthetic effect, with respect to plasma concentrations, was described by the effect compartment, with the rate constant for the distribution to the effector compartment equal to 0.335 min−1. Drug concentration had a large effect on the probability of anesthesia. The degree of anesthesia was largest at 10:00 h, lowest at 16:00 h, and intermediate at 22:00 h. In summary, both the pharmacokinetics and pharmacodynamics of propofol in rabbits depended on administration time. The developed population approach may be used to assess chronopharmacokinetics and chronopharmacodynamics of medications in animals and humans. (Author correspondence: agnbienert@op.pl)

Pharmacokinetic and Pharmacodynamic Interactions of Ethanol and Propofol in Rabbits

Propofol is a short-acting intravenous anesthetic which is rapidly metabolized by glucuronidation and ring hydroxylation catalyzed by cytochrome P450. In clinical trials, it was found that patients receiving both ethanol and propofol injection in the surgery awoke significantly earlier than those who were injected propofol alone. To investigate pharmacokinetic and pharmacodynamic interactions of propofol and ethanol, propofol was injected alone and in combination with ethanol to rabbits. Propofol was injected intravenously at a dose rate of 15 mg kg−1. Ethanol was injected intraperitoneally at a dose rate of 2.5 mg kg−1. An LC assay with native fluorescence detection was developed and validated for determining the concentration of propofol in rabbit plasma and the effect of co-injected ethanol on the plasma pharmacokinetics of propofol in rabbits. Co-injection of ethanol decreased the maximum plasma concentration (Cmax) and area under the plasma concentration–time curve (AUC0–∞) of propofol by 53.28 and 53.42%, respectively, as compared to the control (P < 0.001). Concomitant ethanol also caused a 66.67% increase in plasma clearance (CL) (P < 0.001). These may partially explain the finding that co-injected ethanol reduced the anesthetic effect of propofol by introducing hepatic microsomal drug-metabolizing enzymes activity in rabbits.

Induction of anaesthesia with either midazolam or propofol in rabbits premedicated with fentanyl/fluanisone

Fifty-four rabbits that were to be neutered were premedicated with 0.1 ml/kg fentanyl/fluanisone and then randomly allocated to be anaesthetised with either midazolam or propofol. Anaesthesia was then maintained with...

Effects of propofol on ultrasonic indicators of haemodynamic function in rabbits

ObjectiveTo evaluate the cardiovascular effects of intravenous propofol in rabbits. Study designRandomized, prospective, experimental study. AnimalsThirty-one female New Zealand White rabbits. MethodsRabbits were allocated to one of two groups [propofol (P) or conscious (C)]. In C (n = 16) vascular dimensions were measured using ultrasound of the left common carotid artery (ACC) and the abdominal aorta (AA). Group P (n = 15) received propofol 4.0–8.0 mg kg−1 intravenously (IV). Anaesthesia was maintained with propofol at 1.2–1.3 mg kg−1 minute−1. Subsequently, three propofol injections (8 mg kg−1) were given. Before and for 10 minutes after each injection the following vascular and haemodynamic variables were recorded (a) at the ACC after the first injection; and (b) at the AA after the second injection: vessel diameter [D, (mm)], peak systolic, minimum diastolic, end-diastolic and average blood flow velocities [psBFV, mdBFV, edBFV, Vave (cm second−1)], average volumetric flow [VFave (mL s−1)], resistance index (RI) and pulsatility index (PI) mean arterial pressure (MAP), heart rate (HR), arterial oxygen saturation (SpO2) and end-tidal CO2 (Pe′CO2). Echocardiography was performed after the third propofol bolus injection to investigate changes in cardiac parameters [fractional shortening, FS (%)]. ResultsIntravenous propofol injections caused a significant decrease in vessel diameter, volumetric flow and edBFV, and significant increases in psBFV, RI and PI. Baseline levels for vessel diameter and psBFV were restored 6–8 minutes after injection. Propofol injection decreased FS significantly by 7 minutes after injection while MAP and HR were significantly reduced for 4 minutes.Conclusion and clinical relevance Injections of propofol (8 mg kg−1) produced an immediate, transient decrease in vascular diameters, a significant decrease in ventricular performance and an increase in peripheral vascular resistance (ACC and AA). Propofol should probably not be or only carefully used in rabbits with ventricular dysfunction.

Inflammatory Reactions after Subdermal Injection of Thiopental and Propofol in Rabbits

Background: Thiopental and propofol are the most widely used intravenous anesthetics as induction agents in general anesthesia. Thiopental is a very strong alkaline drug, and when it is extravasated, it can cause pain and skin necrosis. Propofol also can cause pain on injection in many populations. Therefore, we planed this study to compare inflammatory reactions of skin tissues after subdermal injections of thiopental and propofol in rabbits. Methods: Four rabbits were divided into 2 groups: Standard dose (S) group and double dose (D) group. In the S group, thiopental 0.4 ml and propofol 0.4 ml were injected subcutaneoudly on each side of the posterior proximal ear. In the D group, the dose was doubled to 0.8 ml of each drug and injection was done in the same manner. Skin tissue at the injection sites were excised after 1 day, 3 days, and 7 days. Then each skin tissue slide was examined under an optical microsccpe. Results: In the S group, the inflammatory reaction after the subdermal injection of 2.5% thiopental revealed a more progressed and more severe pattern than 1% propofol. In the D group, the inflammatory reaction after a subdermal injection of 2.5% thiopental revealed a more progressed and more severe pattern than 1% propofol at 3 days, but there was no significant difference in the degree of progression and severity between the 2 drugs at 7 days. Conclusions: When propofol is extravasated during continuous infusion for maintenance of anesthesia, it can cause distinct inflammatory reaction; though the inflammatory reaction is milder and the possibility of complications is lower than with thiopental. (Korean J Anesthesiol 2002; 43: 485~493)

Myocardial and coronary effects of propofol in rabbits with compensated cardiac hypertrophy.

Myocardial effects of propofol have been previously investigated but most studies have been performed in healthy hearts. This study compared the cardiac effects of propofol on isolated normal and hypertrophic rabbits hearts. The effects of propofol (10-1,000 microM) on myocardial contractility, relaxation, coronary flow and oxygen consumption were investigated in hearts from rabbits with pressure overload-induced left ventricular hypertrophy (LVH group, n = 20) after aortic abdominal banding and from sham-operated control rabbits (SHAM group, n = 10), using an isolated and erythrocyte-perfused heart model. In addition, to assess the myocardial and coronary effects of propofol in more severe LVH, hearts with a degree of hypertrophy greater than 140% were selected (severe LVH group, n = 7). The cardiac hypertrophy model induced significant left ventricular hypertrophy (136+/-21%, P < 0.05). The pressure-volume relation showed normal systolic function but an altered diastolic compliance in hypertrophic hearts. Propofol only decreased myocardial contractility and relaxation at supratherapeutic concentrations (> or = 300 microM) in SHAM and LVH groups. The decrease in myocardial performances was not significantly different in SHAM and LVH groups. Propofol induced a significant increase in coronary blood flow which was not significantly different between groups. In severe LVH group, the degree of hypertrophy reached to 157+/-23%. Similarly, the effects of concentrations of propofol were not significantly different from the SHAM group. Propofol only decreased myocardial function at supratherapeutic concentrations. The myocardial and coronary effects of propofol were not significantly modified in cardiac hypertrophy.

Myocardial and coronary effects of propofol in rabbits with cardiac hypertrophy

Myocardial and coronary effects of propofol in rabbits with cardiac hypertrophy

The effects of long term sedation with propofol in rabbits

The effects of long term sedation with propofol in rabbits