special communication A self-powered constant infusion device for use in unrestrained rats (original) (raw)
Hemodynamics of Conscious Brattleboro Rats
Annals of the New York Academy of Sciences, 1982
Institute of Physiology Czechoslovak Academy of Sciences Prague 4, CS I42 20 Czechoslovakia Vasopressin exerts distinct cardiovascular effects in many species including the rat.h However, its role in blood pressure regulation is still not c1ear.O Brattleboro rats homozygous for diabetes insipidus (DI) completely lack vasopressin,g while 50% of normal vasopressin synthesis was demonstrated in their heterozygous (HZ) littermates.' Adult female D I and HZ rats were compared in order to ascertain whether the inborn absence of vasopressin could influence their hemodynamics.
Rodent General Anesthesia Suitable for Measurement of Experimental Invasive Hemodynamics
European Journal of Biology and Biotechnology
In cases of experimentally performed invasive rodent cardiovascular measurements, selected general anesthesia for a non-recovery procedure and its proper pain control plays a fundamental role in obtaining good data recordings. Rodent anesthesia is challenging for several reasons including high metabolic rate with elevated possibility of hypothermia and hypoglycemia during the procedure, large body surface area to adjust drug medication and anticipate drug clearance. In this review article, suitable analgesia, and anesthesia to collect rodent hemodynamics is discussed with examples of commonly used methods and anesthetic combinations to assess rodent hemodynamics. In case of injectable anesthesia, hemodynamic parameters should be measured when HR and mean arterial pressure (MAP) becomes stable. If re-injection is necessary, re-evaluation of HR and MAP is crucial for data integrity. Likewise, to safeguard data quality, longitudinal collection of HRs, HR variability, MAP and body tempe...
Multiple simultaneous determinations of hemodynamics and flow distribution in conscious rat
Journal of Pharmacological Methods, 1984
A method for multiple simultaneous determinations of cardiocirculatory dynamics, regional blood flow, and total cardiac output distribution in the conscious rat preparation is described. The preparation allows for intravenous administration of agents and can be performed on animals either at rest or during treadmill exercise. Instrumentation procedures involve placement of fluid-filled catheters in the left ventricle, right atria, right jugular vein, and caudal artery. Left ventricular pressures are recorded via a modified 4F Millar transducer-tipped manometer containing a IO-cm extension of fluid-filled PE 50 placed into the left ventricle via the right carotid artery. Radionuclide-labeled microspheres (15 k 5 k) are injected into the left ventricle through the fluid-filled PE 50 at selected times for determination of cardiac output and regional blood flows using the caudal artery catheter as the source of the reference blood sample. Details and selected validation data for procedures involving anesthesia, instrumentation, recovery from anesthesia, data gathering, and data analysis are presented. Emphasis is placed on the procedures required for use of the radioactive microsphere technique in this model with special attention given to quality control of the microsphere stock, counting procedures, and computer analysis of these data.
Flow-induced errors in estimating perfusion pressure of the isolated rat kidney
Kidney International, 1982
The isolated perfused rat kidney has proven to be a very useful model for the assessment of the intrinsic renal actions of agents in a setting devoid of extrarenal influences (for review see [I]). A cell-free artificial medium of defined composition is employed usually for reasons of economy, as well as experimental design. The low viscosity of such media results in relatively high perfusate flow rates. The small size of the renal artery of the rat dictates the use of small-bore arterial cannulas that exhibit a significant resistance and induce a large decrement in pressure at the high flow rates encountered with this preparation. Since perfusion pressure is routinely monitored proximal to the arterial cannula, the pressure drop imposed by the cannula represents a potential source of error in the estimation of renal perfusion pressure. Furthermore, since perfusion pressure is an important determinant of renal function, such an erroneous estimation of this parameter may alter observed renal function inadvertently, thereby confounding the interpretation of results obtained with this model.
A new dynamic model for in vitro evaluation of intravascular devices
The International Journal of Artificial Organs, 2018
Introduction: A dynamic model to evaluate thrombus formation on intravascular catheters in vitro is presented. The model enables fluid infusion, variation in the catheter orientation, and variable flow conditions. It was applied on a catheter used to shunt cerebrospinal fluid to a vein, a dural venous sinus, for the treatment of hydrocephalus. Methods: Fresh human blood-filled circuits were circulated in a non-occlusive roller pump. A catheter infused either with cerebrospinal fluid, Ringer’s lactate, or no fluid (control) was inserted through each circuit’s wall. Sixteen circuits (six cerebrospinal fluid, six Ringer’s lactate, four control) ran for 60 min. Qualitative assessment was performed by measuring viscoelastic properties of blood at the start and end of the experiment; quantitative evaluation of clot formation by scanning electron microscope. Results: Average blood velocity was 79 mm/s, with a pressure wave between 5 and 15 mm Hg. At the experiment’s end, the infused fluid ...
Resuscitation, 2006
Background: The intrathoracic pressure regulator (ITPR) was created to improve hemodynamics by generating continuous negative airway pressure between positive pressure ventilations to enhance cardiac preload in apnoeic animals. In normovolemic and hypovolemic pigs, we tested the hypothesis that continuous negative intrathoracic pressure set at −5 or −10 mmHg, interrupted only for intermittent positive pressure ventilations, would decrease intracranial (ICP) and right atrial (RAP) pressure, and increase mean arterial pressure (MAP). Methods: Twelve pigs were anesthetized with propofol and ventilated with a bag. The ITPR was used to vary baseline endotracheal pressures (ETPs) for 5 min periods in the following sequence: 0, −5, 0, −10, 0 mmHg under normovolemic conditions. Six pigs were bled 50% (32.5 ± mL/kg) of their estimated blood volume and the airway pressure sequence was repeated. Six other pigs were bled 35% (22.75 ± mL/kg) of their estimated blood volume and the same airway pressure sequence was repeated. Intracranial, aortic, right atrial pressures, arterial blood gases, end tidal CO 2 (ETCO 2 ), were measured. ANOVA was used for statistical analysis. Linear regression analysis was performed for ETP and ICP.
Comparison among different methods for blood pressure monitoring in rats: literature review
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Veterinary Medicine, 2019
Blood pressure is a cardinal vital sign that gives important information about the cardiovascular function and about hemodynamic trends during anaesthesia, in critical ill patients and during experimental procedures (Rehman and Nelson, 2018). Arterial blood pressure can be evaluated by direct technique (arterial catheter) or indirect technique (Doppler or oscillometry). Direct measurement is gold standard for blood pressure measurement, giving accurate beat-to-beat information and also allow collection of blood samples. However, it is more invasive and requires equipment for monitoring and experience to place the arterial catheter (Araghi et al., 2006; Ward and Langton, 2007; Wingfield and Raffe, 2002). Given its importance in directing care, it is essential to measure blood pressure accurately and consistently.The aim of this article is to present all technique found in literature, with its advantages and disadvantages, with the errors that may occur so that the researchers can hav...
Direct and indirect methods used to study arterial blood pressure
Journal of Pharmacological and Toxicological Methods, 2000
A number of different approaches exist for assessing blood pressure in experimental animals. Here, we briefly consider the traditional indirect (rodent tail-cuff) and direct (saline-filled catheter) methods of blood pressure measurement before going on to describe our experience with blood pressure telemetry in rabbits, rats, and mice. Blood pressure telemetry offers the ability to obtain a high-fidelity recording of blood pressure continuously, for relatively long periods of time, in conscious, freely moving animals, without the limitations of restraint or anaesthesia. Since some drift in telemeter offset and sensitivity are inevitable, recalibration of the telemeter devices immediately before implantation and following explantation is essential to ensure and document the accuracy of the blood pressure measurements. For long-term implantations, verification of the calibration can be performed in vivo, at least in the case of large animals, such as rabbits. Telemetry devices suitable for small animals, such as mice, are also available now, which will facilitate the accurate characterization of blood pressure in transgenic animals. Telemeter implantation methods in mice are presently difficult, with relatively low success rates being reported. However, validation of new methods, such as the insertion of the catheter tip via the carotid artery, may make the technique more widely accessible in the near future.