A Non-invasive Method of Cerebrospinal fluid collection from rats for assessing the Cerebrospinal fluid drug content

The drug discovery and pharmacokinetic studies of drugs of the central nervous system depend on the successful collection of cerebrospinal fluid from lab animal models. Many a time, the treatment regime and management of diseases depends on the penetration and distribution of medicaments across the blood-brain barrier and for which a non-contaminated cerebrospinal fluid sample is essential. The present study was to simplify the cerebrospinal fluid collection from cisterna magna of rat, maximizing the quantity and minimizing the contamination. The rat is anaesthetized with Xylazine Ketamine combination intravenously and was kept on an inverted polypropylene tray with its head down at 45° angle. A depressible surface which look like a rhomb between occipital protuberances and the spine of the atlas becomes noticeable. A butterfly needle attached to a syringe was introduced into the cisterna magna, and cerebrospinal fluid is aspirated. The method is non-invasive and doesn’t require any sophisticated equipment and lessens the chance of contamination of the sample with blood. The technique is also less time consuming and easy to perform.

Routine coagulation testing in Vacutainer® Citrate Plus tubes filled at minimum or optimal volume

BackgroundFilling of citrate tubes with appropriate amount of blood is essential for obtaining reliable results of coagulation testing. This study aimed to verify whether results of routine coagulation tests are comparable when the new Becton Dickinson Vacutainer® Citrate Plus tubes are filled at minimum or optimal volume.MethodsThe study population consisted of 133 patients (40 on oral anticoagulant therapy), who had blood collected for routine coagulation testing. Two sequential Vacutainer® Citrate Plus tubes of the same type and lot were drawn. The first tube was collected after a butterfly needle was inserted into the vein, so that the air in the tubing was aspirated into the tube before blood (minimum fill volume), whilst the second was drawn at optimal fill volume. Experiments were repeated using 2.7-mL (n = 86) and 1.8-mL (n = 47) tubes.ResultsProthrombin time (PT) and fibrinogen values were slightly but significantly decreased in tubes with minimum than in those with optimal fill volume. The activated partial thromboplastin time (APTT) was slightly prolonged in tubes with minimum than in those with optimal fill volume, but the difference was not statistically significant. An identical trend was noted in separate analyses for the 2.7-mL and 1.8-mL tubes. Spearman’s correlations between the two fill volumes were always >0.94 and bias was always within the quality specifications.ConclusionsBlood drawing into Vacutainer® Citrate Plus tubes at minimum fill volume does not clinically bias routine coagulation testing.

VALVE SELECTION FOR THE PURPOSE OF REDUCING THE WATER HAMMER EFFECT IN A PRESSURIZED PIPELINE

This paper discusses the gravity-fed hydraulic system, which consists of the upper reservoir, the lower reservoir, the pipeline, and valves. To achieve simpler and more efficient protection of a system against water hammer, it is advisable to establish conditions in which the pressure rises as little as possible during transient regimes without using any protective equipment. The discussion focuses on the pressure rise caused by different valve types: butterfly, needle, and ball valves, as well as two valve closure intervals – 20 and 40 seconds. The systems considered have nominal diameters of DN 300 and DN 600. The problem was studied using a simulation of unsteady flow regimes of hydraulic transport. The obtained results regarding the maximum pressure rise due to water hammer were used to select the most satisfactory control valve for the considered hydraulic system.

WED 079 Epidural blood patch: impact of non-luer one-way butterfly needle

The epidural blood patch (EBP) requires a syringe that connects to the intravenous and epidural route. Thereby contravening Department of Health guidance, which recommends adoption of equipment that, prevents wrong route drug administration. To comply with these recommendations a non-Luer butterfly needle with one-way valve has been produced by GBUK. The one-way valve and length of tubing has the potential of activating the clotting cascade. This could reduce the time clinicians have to utilise the blood in the syringe. Also any alteration in clotting could affect the therapeutic value of the EBP. The primary objective of this research was to determine if phlebotomy using this new 21G needle altered blood clotting, determined by thromboelastograph analysis, compared to a standard 21G hypodermic needle.We performed paired phlebotomy on 10 healthy volunteers; producing a study capable of revealing a 25% change in R-time (power 80%). Mean R-time was increased with the new needle, however remaining within normal range (7.3 vs 6.6 min (p=0.04)). This would not limit the time to utilise the blood before clot formation in the syringe. With no clinically relevant difference in MA or LY30, it is unlikely to have any impact on the therapeutic value of the EBP.

Endoscopic vocal fold injection using a 25-gauge butterfly needle

Objective:To describe a useful technique for infiltrating a bulking agent using a butterfly needle, as part of a transoral endoscopic vocal fold medialisation procedure.Methods:This paper describes the procedure of grasping the needle with phonosurgery forceps and administering the injectate to the vocal fold through careful application of the syringe plunger via a length of rubber tubing from outside the mouth.Results:This procedure is performed routinely in our institution without complication. The advantages of this technique are discussed.Conclusion:This is a safe and easy method of injecting into a vocal fold.

What is the risk of infecting a cerebrospinal fluid–diverting shunt with percutaneous tapping?

Object Most CSF-diverting shunt systems have an access port that can be percutaneously tapped. Tapping the shunt can yield valuable information as to its function and whether an infection is present. The fear of causing a shunt infection by tapping may limit the physician's willingness to do so. The authors of this study investigate the risk of infecting a shunt secondary to percutaneous tapping. Methods Following institutional review board approval, CSF specimens obtained from tapping an indwelling CSF-diverting shunt during the 2011 and 2012 calendar years were identified and matched with clinical information. A culture-positive CSF sample was defined as an infection. If results were equivocal, such as a broth-only–positive culture, a repeat CSF specimen was examined. The CSF was obtained by tapping the shunt access port with a 25-gauge butterfly needle after prepping the unshaven skin with chlorhexidine. Results During the study period, 266 children underwent 542 shunt taps. With 541 taps, no clinical evidence of a subsequent shunt infection was found. One child's CSF went from sterile to infected 11 days later; however, this patient had redness along the shunt tract at the time of the initial sterile tap. Conclusions The risk of infection from tapping a shunt is remote if the procedure is done correctly.