query: the medical procedure for drawing a sample of venous blood into a vacuum tube is known as

pos: Venipuncture Venipuncture In medicine, venipuncture or venepuncture is the process of obtaining intravenous access for the purpose of intravenous therapy or for blood sampling of venous blood. In healthcare, this procedure is performed by medical laboratory scientists, medical practitioners, some EMTs, paramedics, phlebotomists, dialysis technicians, and other nursing staff. In veterinary medicine, the procedure is performed by veterinarians and veterinary technicians. It is essential to follow a standard procedure for the collection of blood specimen to get the accurate laboratory results. Any kind of error in collection of blood or filing the test tubes may lead erroneous laboratory results. Venipuncture is

pos: Complete blood count of red blood cells or platelets should be planned based on that. Multiple blood draws and counts throughout the day are an excessive use of phlebotomy and can lead to unnecessary additional transfusions, and the extra unnecessary treatment would be outside of medical guidelines. A phlebotomist collects the sample through venipuncture, drawing the blood into a test tube containing an anticoagulant (EDTA, sometimes citrate) to stop it from clotting. The sample is then transported to a laboratory. Sometimes the sample is drawn off a finger prick using a Pasteur pipette for immediate processing by an automated counter. Before the advent

pos: Venous blood higher concentrations of urea and other waste products. The difference in the oxygen content of arterial blood and venous blood is known as the arteriovenous oxygen difference. Most medical laboratory tests are conducted on venous blood, with the exception of arterial blood gas tests. Venous blood is obtained for lab work by venipuncture (also called phlebotomy), or by finger prick for small quantities. Human blood is red in color, ranging from bright red when oxygenated to a very dark, almost blackish-red when deoxygenated. It owes its color to haemoglobin, to which oxygen binds. Deoxygenated blood is darker due to the

pos: Reference ranges for blood tests range for a blood test is generally the venous range, as the standard process of obtaining a sample is by venipuncture. An exception is for acid-base and blood gases, which are generally given for arterial blood. Still, the blood values are approximately equal between the arterial and venous sides for most substances, with the exception of acid-base, blood gases and drugs (used in therapeutic drug monitoring (TDM) assays). Arterial levels for drugs are generally higher than venous levels because of extraction while passing through tissues. Reference ranges are usually given as what are the usual (or "normal") values found in

pos: Venipuncture stopper, the tube's vacuum automatically pulls in the required volume of blood. The basic Evacuated Tube System (ETS) consists of a needle, a tube holder, and the evacuated tubes. The needle is attached to the tube holder by the phlebotomist prior to collection, or may come from the manufacturer as one unit. the needle protrudes through the end of the tube holder, and has a needle on each end. After first cleaning the venipuncture site and applying a tourniquet, the phlebotomist uncaps the needle attached to the tube holder, inserts the needle into the vein, then slides evacuated tubes into

neg: Peripheral venous catheter Peripheral venous catheter In medicine, a peripheral venous catheter (PVC), peripheral venous line or peripheral venous access catheter is a catheter (small, flexible tube) placed into a peripheral vein for intravenous therapy such as medication fluids. Upon insertion, the line can be used to draw blood. The catheter is introduced into the vein by a needle (similar to blood drawing), which is subsequently removed while the small tube of the cannula remains in place. The catheter is then fixed by taping it to the patient's skin (unless there is allergy to adhesives). Newer catheters have been equipped with additional safety

neg: Anomalous pulmonary venous connection which involves rerouting blood from the right atrium into the left atrium with a patch or use of the Warden procedure. However, interest is increasing in catheter-based interventional approaches, as well as medical therapy for less severe cases. Anomalous pulmonary venous connection Anomalous pulmonary venous connection (or anomalous pulmonary venous drainage or anomalous pulmonary venous return) is a congenital defect of the pulmonary veins. "Total anomalous pulmonary venous connection", also known as total "anomalous pulmonary venous return", is a rare cyanotic congenital heart defect in which all four pulmonary veins are malpositioned and make anomalous connections to the systemic venous

neg: Venipuncture the tube holder, where the tube's stopper is pierced by the back end of the needle. The vacuum in the tube then automatically draws the needed blood directly from the patient's vein. Multiple vacuum tubes can be attached to and removed in turn from a single needle, allowing multiple samples to be obtained from a single procedure. This is possible due to the multiple sample sleeve, which is a flexible rubber fitting over the posterior end of the needle cannula which seals the needle until it is pushed out of the way. This keeps blood from freely draining out of

neg: Radial artery puncture Radial artery puncture Radial artery puncture is a medical procedure performed to obtain a sample of arterial blood for gas analysis. A needle is inserted into the radial artery and spontaneously fills with blood. The syringe is either prepacked with a small amount of heparin to prevent coagulation, or must be "heparinised", by drawing up a small amount of heparin and squirting it out again. Most commonly, radial artery puncture is performed to obtain arterial blood sampling for gas analysis. The partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2), and the pH of arterial blood are important in assessing

neg: Criminal procedure in South Africa take such steps (including the drawing of blood samples) as may be necessary to ascertain whether the body has a "mark, characteristic or distinguishing feature," as contemplated in section 37(2). The medical officer of a prison and a district surgeon do not need a police request to proceed in this way, but other medical practitioners and nurses do. In terms of section 37(2)(b), a medical practitioner attached to a hospital may take a blood sample of a person admitted to the hospital if he is of the reasonable opinion that such a sample may be relevant at later criminal proceedings.

neg: Chronic cerebrospinal venous insufficiency Chronic cerebrospinal venous insufficiency Chronic cerebrospinal venous insufficiency (CCSVI or CCVI) is a term developed by Italian researcher Paolo Zamboni in 2008 to describe compromised flow of blood in the veins draining the central nervous system. Zamboni hypothesized that it played a role in the cause or development of multiple sclerosis (MS). Zamboni also devised a procedure which was termed by the media as "liberation procedure" or "liberation therapy", involving venoplasty (or stenting) of certain veins in an attempt to improve blood flow. Within the medical community, both the procedure and CCSVI have been met with skepticism. Zamboni's first published

neg: Vacutainer The amount of air evacuated from the tube predetermines how much blood will fill the tube before blood stops flowing. Each tube is topped with a color-coded plastic or rubber cap. Tubes often include additives that mix with the blood when collected, and the color of each tube's plastic cap indicates which additives it contains. Blood collection tubes expire because over time the vacuum is lost and blood will not be drawn into the tube when the needle punctures the cap. Vacutainer tubes may contain additional substances that preserve blood for processing in a medical laboratory. Using the wrong tube

neg: Glucose tolerance test sample capillary or finger-prick blood, which is less invasive, more convenient for the patient and requires minimal training to conduct. Though fasting blood glucose levels have been shown to be similar in both capillary and venous samples, postprandial blood glucose levels (those measured after a meal) can vary. The diagnosis criteria issued by the WHO are only suitable for venous blood samples. Given the increasing popularity of capillary testing, the WHO has recommended that a conversion factor between the two sample types be calculated, but no conversion factor had been issued by the WHO, despite some medical professionals adopting their

neg: Vascular access for chemotherapy Vascular access for chemotherapy In medicine, vascular access is a means of accessing the circulatory system through the peripheral or central vascular system in order to obtain blood or deliver medications . A vascular access procedure involves insertion of a sterile plastic tube called a catheter into a blood vessel. Types of catheters can be either peripherally or centrally located. Peripheral catheters are approximately one inch long and are inserted into the small veins of the forearm. Central catheters are bigger and longer and are inserted into the large veins of the extremities, neck, or chest. Central venous catheters is

neg: Venipuncture circumstances, a syringe may be used, often with a butterfly needle, which is a plastic catheter attached to a short needle. In the developing world, the evacuated tube system is the preferred method of drawing blood Greiner Bio-One manufactured the first ever plastic evacuated blood collection tube in 1985 under the VACUETTE brand name. Today, many companies sell vacuum tubes as the patent for this device is now in the public domain. These tubes are manufactured with a specific volume of gas removed from the sealed tube. When a needle from a hub or transfer device is inserted into the

neg: Radial artery puncture the lateral aspect of the volar forearm deep to the superficial fascia. The artery runs between the styloid process of the radius and the flexor carpi radialis tendon. The point of maximum pulsation of the radial artery can usually be palpated just proximal to the wrist. Radial artery puncture Radial artery puncture is a medical procedure performed to obtain a sample of arterial blood for gas analysis. A needle is inserted into the radial artery and spontaneously fills with blood. The syringe is either prepacked with a small amount of heparin to prevent coagulation, or must be "heparinised", by drawing

neg: Rectal venous plexus series of dilated pouches which are arranged in a circle around the tube, immediately above the anal orifice, and are connected by transverse branches. This internal plexus is also known in some medical communities as the Irving plexus. The veins of the hemorrhoidal plexus are contained in very loose connective tissue, so that they get less support from surrounding structures than most other veins, and are less capable of resisting increased blood-pressure. Rectal venous plexus The rectal venous plexus (or hemorrhoidal plexus) surrounds the rectum, and communicates in front with the vesical venous plexus in the male, and the vaginal

neg: Vacuum aspiration weeks gestational age. Other complications occur at a rate of less than 1 per 100 procedures and include excessive blood loss, infection, injury to the cervix or uterus, including perforation, and uterine adhesions. Vacuum aspiration Vacuum or suction aspiration uses aspiration to remove uterine contents through the cervix. It may be used as a method of induced abortion, a therapeutic procedure used after miscarriage, or a procedure to obtain a sample for endometrial biopsy. The rate of infection is lower than any other surgical abortion procedure at 0.5%. Some sources may use the terms "dilation and evacuation" or "suction" "dilation

neg: Serum-separating tube particles to cause blood to clot quickly. The blood sample may then be centrifuged, allowing the clear serum to be removed for testing. These tubes should be used with care when measuring drug or hormone levels because the drug or hormone may diffuse from the serum into the gel, causing a reduction in measured level. The gel in SST II tubes (which appears slightly less opaque) is supposed to have less effect on drug levels in serum. Serum-separating tube Serum-separating tubes, also known as serum separator tubes or SSTs, are used in medical clinical chemistry tests requiring blood serum. SSTs

neg: Angiography breath-hold time than MRI. Fluorescein angiography is a medical procedure in which a fluorescent dye is injected into the bloodstream. The dye highlights the blood vessels in the back of the eye so they can be photographed. This test is often used to manage eye disorders. An ocular OCT angiography (OCTA) imaging technique, is currently under development to simulate results of fluorescein angiography without the need to inject intravenous dye into patients. Microangiography is commonly used to visualize tiny blood vessels. Another increasingly common angiographic procedure is neuro-vascular digital subtraction angiography in order to visualise the arterial and venous supply

neg: British Columbia Ambulance Service arrest. Their additional training and skills include the use and monitoring of Incubators, Endotracheal (ET) Intubation, Intraosseous (IO) Access, nasogastric (NG) tube insertion and suctioning, manual defibrillation, cardioversion, chest decompression, Venous pressure monitoring, Arterial & Central Line Monitoring, Chest Tube Management, transthoracic pacing, Blood Product Infusion, IV Infusion Devices, 'IV with Medication' Maintenance, Mechanical Ventilation (using the LTV 1000 and 1200 and BMD CrossVent), Foreign body removal with laryngoscope, ET/IO/PR drug administration, Central & Parenteral Line Management, Venous & Arterial blood sample collection, point of collection analysis of ABG's and chemistry using the I-Stat, Lab & X-ray interpretation. The ITT

neg: Glucose tolerance test recommends a two-step procedure, wherein the first step is a 50 g glucose dose. If it results in a blood glucose level of more than 7.8 mmol/L (140 mg/dL), it is followed by a 100 g glucose dose. The diagnosis of gestational diabetes is then defined by a blood glucose level exceeding the cutoff value on at least two intervals, with cutoffs as follows: The diagnosis criteria stated above by the World Health Organisation (WHO) are for venous samples only (a blood sample taken from a vein in the arm). An increasingly popular method for measuring blood glucose is to

neg: Keidel vacuum Keidel vacuum The Keidel vacuum tube was a type of blood collecting device, first manufactured by Hynson, Wescott and Dunning in around 1922. This vacuum was one of the first evacuated systems, predating the more well known Vacutainer. Its primary use was to test for syphilis and typhoid fever. Essentially, the Keidel vacuum consists of a sealed ampule with or without a culture medium. Connected to the ampule was a short rubber tube with a needle at the end, using a small glass tube as a cap. The insertion of the needle into the vein crushes the ampule, thus creating

neg: Hypoglycemia properly obtained from a person whose laboratory serum glucose was 53 mg/dL; even wider variations can occur with "real world" home use. Two other factors significantly affect glucose measurement: hematocrit and delay after blood drawing. The disparity between venous and whole blood concentrations is greater when the hematocrit is high, as in newborn infants, or adults with polycythemia. High neonatal hematocrits are particularly likely to confound glucose measurement by meter. Second, unless the specimen is drawn into a fluoride tube or processed immediately to separate the serum or plasma from the cells, the measurable glucose will be gradually lowered by

neg: Angioscopy Angioscopy Angioscopy is a medical technique for visualizing the interior of blood vessels. In this technique, a flexible fibre bundle endoscope catheter is inserted directly into an artery. It can be helpful in diagnosing e.g. arterial embolism. Angioscopy is also used as an adjunctive procedure during vascular bypass to visualize valves within venous conduits. The instrument used to perform angioscopy is called as angioscope. Scanning Fiber Endoscope (SFE) is an emerging technology which provides much higher resolution imaging, whilst maintaining a small form factor and flexibility. Coronary artery angioscopy, which first was used to reveal the presence of a blood

neg: Kawashima procedure Kawashima procedure The Kawashima procedure is used for congenital heart disease with a single effective ventricle and an "interrupted inferior vena cava" (IVC). It was first performed in 1978 and reported in 1984. Technically it is very similar to the Bidirectional Glenn procedure used to direct half the body's venous blood flow into the lungs. However, in patients with interrupted IVC, most of the blood from the lower body actually joins the blood from the upper body before returning to the heart via the superior vena cava (SVC). Therefore, the redirection of SVC blood to the lungs (as in the

neg: Cerebral venous sinus thrombosis tests give unclear results or when other treatments may be administered during the same procedure. There is an association between the D-dimer blood test and cerebral venous sinus thrombosis. This association however is not strong enough to rule out the diagnosis alone. In most patients, the direct cause for the cerebral sinus thrombosis is not readily apparent. Identifying a source of infection is crucial; it is common practice to screen for various forms of thrombophilia (a propensity to form blood clots). The veins of the brain, both the superficial veins and the deep venous system, empty into the dural venous

neg: DNA methylation un-methylated and venous blood marker B is methylated in a fluid, it indicates the presence of only venous blood. In contrast, if venous blood marker A is methylated and venous blood marker B is un-methylated in some fluid, then that indicates venous blood is in a mixture of fluids. Some examples for DNA methylation markers are Mens1(menstrual blood), Spei1(saliva), and Sperm2(seminal fluid). DNA methylation provides a relatively good means of sensitivity when identifying and detecting body fluids. In one study, only ten nanograms of a sample was necessary to ascertain successful results. DNA methylation provides a good discernment of mixed

neg: Senning procedure Senning procedure Senning procedure is an atrial switch heart operation performed to treat transposition of the great arteries. It is named after its inventor, the Swedish cardiac surgeon Åke Senning (1915–2000), also known for implanting the first permanent cardiac pacemaker in 1958. This procedure, a form of atrial switch, was developed and first performed by Senning in 1957 as a treatment for d-TGA (dextro-Transposition of the great arteries) before improvements in cardiopulmonary bypass made more curative surgical techniques feasible. In this common congenital heart defect, the venous circulation drains into the right ventricle but from this chamber, blood is directed

neg: Neonatal heel prick Neonatal heel prick The neonatal heel prick is a blood collection procedure done on newborns. It consists of making a pinprick puncture in one heel of the newborn to collect their blood. This technique is used frequently as the main way to collect blood from neonates. Other techniques include venous or arterial needle sticks, cord blood sampling, or umbilical line collection. This technique is often utilized for the Guthrie test, where it is used to soak the blood into pre-printed collection cards known as Guthrie cards. The classical Guthrie test is named after Robert Guthrie, an American bacteriologist and physician

neg: Cannula of intravenous fluids, for obtaining blood samples and for administering medicines. An arterial cannula is inserted into an artery, commonly the radial artery, and is used during major operations and in critical care areas to measure beat-to-beat blood pressure and to draw repeated blood samples. Insertion of the venous cannula is a painful procedure that can lead to anxiety and stress. Use of a vapocoolant (cold spray) immediately before cannulation reduces pain during the procedure, without increasing the difficulty of cannulation. Complications may arise in the vein as a result of the cannulation procedure, the four main groups of complication

neg: Valvulotome Valvulotome A valvulotome is a medical device used to destroy the venous valves in especially the great saphenous vein to allow for arterial flow. Since the leg veins usually contain a number of valves that direct flow towards the heart, they cannot directly be used as graft, but if vein valves are removed the arterial blood can flow via the GSV to the lower leg - this is called an in situ graft procedure, a type of vascular bypass. The valvulotome itself is a long, flexible catheter with a recessed cutting blade at its end for the destruction of venous

neg: Heart sounds intrathoracic pressure which allows more venous blood to return to the right heart (pulling blood into the right side of the heart via a vacuum-like effect). Therefore, right-sided heart murmurs generally increase in intensity with inhalation. The decreased (more negative) intrathoracic pressure has an opposite effect on the left side of the heart, making it harder for the blood to exit into circulation. Therefore, left-sided murmurs generally decrease in intensity during inhalation. Increasing venous blood return to the right side of the heart by raising a patient's legs to a 45-degree while lying supine produces similar effect which occurs during

neg: Vacutainer contained the preservative EDTA. Had this been true, it would have meant that the droplet might have been taken from the purple top tube used to collect Simpson's blood and planted at the crime scene. Vacutainer A Vacutainer blood collection tube is a sterile glass or plastic test tube with a colored rubber stopper creating a vacuum seal inside of the tube, facilitating the drawing of a predetermined volume of liquid. Vacutainer tubes may contain additives designed to stabilize and preserve the specimen prior to analytical testing. Tubes are available with a safety-engineered stopper, with a variety of labeling options

neg: Blood-spinning Blood-spinning Blood-spinning is a medical procedure used to shorten the healing time of an injury. Small samples of the patient's blood are taken and spun in a centrifuge, allowing platelets and blood plasma to be isolated from other blood components. The platelets and plasma are then combined forming platelet-rich plasma (PRP), which has high concentrations of natural growth factors. The PRP sample can then be injected into the patient's injury, which may help reduce pain and improve recovery speeds. This procedure has been deemed controversial at times, especially when used by athletes. In 2005, the World Anti-Doping Agency ruled that

neg: Keidel vacuum a vacuum and forcing blood into the container. Typically, a prominent vein in the forearm such as the median cubital vein would suffice, although the Keidel vacuum can take blood for any prominent peripheral vein. This concept did not become popular until during World War II, when quick and efficient first aid care was necessary in the battle field. As a result, the vacutainer became the forefront device used for blood collection. Keidel vacuum The Keidel vacuum tube was a type of blood collecting device, first manufactured by Hynson, Wescott and Dunning in around 1922. This vacuum was one of

neg: Angioscopy clot in the coronary arteries of patients with unstable angina and myocardial infarction, is now widely used in catherization laboratories to visualize stents. Angioscopy Angioscopy is a medical technique for visualizing the interior of blood vessels. In this technique, a flexible fibre bundle endoscope catheter is inserted directly into an artery. It can be helpful in diagnosing e.g. arterial embolism. Angioscopy is also used as an adjunctive procedure during vascular bypass to visualize valves within venous conduits. The instrument used to perform angioscopy is called as angioscope. Scanning Fiber Endoscope (SFE) is an emerging technology which provides much higher resolution

neg: Magnetic resonance imaging is due to blood that recently moved into that plane (see also FLASH MRI). Techniques involving phase accumulation (known as phase contrast angiography) can also be used to generate flow velocity maps easily and accurately. Magnetic resonance venography (MRV) is a similar procedure that is used to image veins. In this method, the tissue is now excited inferiorly, while the signal is gathered in the plane immediately superior to the excitation plane—thus imaging the venous blood that recently moved from the excited plane. MRI for imaging anatomical structures or blood flow do not require contrast agents as the varying properties

neg: Intraoperative blood salvage Intraoperative blood salvage Intraoperative blood salvage, also known as autologous blood transfusion or cell salvage, is a medical procedure involving recovering blood lost during surgery and re-infusing it into the patient. It is a major form of autotransfusion. It has been used for many years and gained greater attention over time as risks associated with allogenic (separate-donor) blood transfusion (source?) have seen greater publicity and become more fully appreciated. Several medical devices have been developed to assist in salvaging the patient's own blood in the perioperative setting. The procedure is frequently used in cardiothoracic and vascular surgery, during which blood

neg: Intermittent vacuum therapy Intermittent vacuum therapy The Intermittent Vacuum Therapy (IVT) is a treatment conducted in case of venous and arterial issues as well as in rehabilitation (after sports injuries and vascular complaints). With the aid of normal and low pressure, it should enable to control venous reflux, enhance lymphatic flow and improve blood flow in periphery and muscles. The IVT treatment device consists of a cylindrical space in which the lower body of a lying patient (up until the ribs) is enclosed and affected. The legs are fully comprised. In the waist region, the inner space of the device is sealed by

neg: Seldinger technique used to close the hole made by the procedure. The Seldinger technique is used for angiography, insertion of chest drains and central venous catheters, insertion of PEG tubes using the push technique, insertion of the leads for an artificial pacemaker or implantable cardioverter-defibrillator, and numerous other interventional medical procedures. The initial puncture is with a sharp instrument, and this may lead to hemorrhage or perforation of the organ in question. Infection is a possible complication, and hence asepsis is practiced during most Seldinger procedures. Loss of the guidewire into the cavity or blood vessel is a significant and generally preventable

neg: Hematocrit tube) at 10,000 RPM for five minutes. This separates the blood into layers. The volume of packed red blood cells divided by the total volume of the blood sample gives the PCV. Since a tube is used, this can be calculated by measuring the lengths of the layers. Another way of measuring hematocrit levels is by optical methods such as spectrophotometry. Through differential spectrophotometry, the differences in optical densities of a blood sample flowing through small-bore glass tubes at isosbestic wavelengths for deoxyhemoglobin and oxyhemoglobin and the product of the luminal diameter and hematocrit create a linear relationship that is

neg: Chronic venous insufficiency Chronic venous insufficiency Chronic venous insufficiency (CVI) is a medical condition in which blood pools in the veins, straining the walls of the vein. The most common cause of CVI is superficial venous reflux which is a treatable condition. As functional venous valves are required to provide for efficient blood return from the lower extremities, this condition typically affects the legs. If the impaired vein function causes significant symptoms, such as swelling and ulcer formation, it is referred to as chronic venous disease. It is sometimes called "chronic peripheral venous insufficiency" and should not be confused with post-thrombotic syndrome in

neg: Fetoscopy Fetoscopy Fetoscopy is an endoscopic procedure during pregnancy to allow surgical access to the fetus, the amniotic cavity, the umbilical cord, and the fetal side of the placenta. A small (3–4 mm) incision is made in the abdomen, and an endoscope is inserted through the abdominal wall and uterus into the amniotic cavity. Fetoscopy allows for medical interventions such as a biopsy (tissue sample) or a laser occlusion of abnormal blood vessels (such as chorioangioma) or the treatment of spina bifida. Fetoscopy is usually performed in the second or third trimester of pregnancy. The procedure can place the fetus at

neg: Norwood procedure is the separation of the systemic and pulmonary circulation once pulmonary vascular resistance has fallen, by removing the aortopulmonary shunt followed by the creation of a bidirectional SVC-pulmonary shunt, also known as a modified Glenn procedure or Hemi-Fontan. The third surgery (Stage 3) is the Fontan procedure, in which the inferior vena cava (IVC, the large vein carrying blood back to the heart from the lower part of the body) is connected to the branch pulmonary arteries. After this surgery is completed, all the venous blood returning from the body flows directly to the lungs. The first successful use of

neg: Dissolved gas analysis is a gas tight borosilicate glass tube of capacity 150 ml or 250 ml, having two airtight Teflon valves on both the ends. The outlets of these valves have been provided with a screw thread which helps in convenient connection of synthetic tubes while drawing sample from transformer. Also this provision is useful in transferring the oil into Sample oil burette of the Multiple Gas Extractor without any exposure to atmosphere, thereby retaining all its dissolved and evolved fault gases contents. It has a septum arrangement on one side of the tube for drawing sample oil to test its moisture

neg: Vein limbs. The Thebesian veins within the myocardium of the heart are valveless veins that drain directly into the chambers of the heart. The coronary veins all empty into the coronary sinus which empties into the right atrium. The dural venous sinuses within the dura mater surrounding the brain receive blood from the brain and also are a point of entry of cerebrospinal fluid from arachnoid villi absorption. Blood eventually enters the internal jugular vein. "Phlebology" is the medical specialty devoted to the diagnosis and treatment of venous disorders. A medical specialist in phlebology is termed a phlebologist. A related image

neg: Fingerstick Fingerstick In medicine, some blood tests are conducted on venous blood obtained by fingerstick (or fingerprick) (or, for neonates, by an analogous heelprick). The site, free of surface arterial flow, where the blood is to be collected is sterilized with a topical germicide, and the skin pierced with a sterile lancet. After a droplet has formed, venous blood is captured in a capillary tube (usually relying on surface tension). Blood cells drawn from fingersticks have a tendency to undergo hemolysis, especially if the finger is "milked" to obtain more blood. Tests commonly conducted on the capillary blood collected are: Fingersticks

neg: Venous ulcer and evaluation (known as the Bisgaard regimen). Exercise together with compression stocking increases healing. There is no evidence that antibiotics, whether administered intravenously or by mouth, are useful. Silver products are also not typically useful, while there is some evidence of benefit from cadexomer iodine creams. There is a lack of quality evidence regarding the use of medical grade honey for venous leg ulcers. Non-elastic, ambulatory, below knee (BK) compression counters the impact of reflux on venous pump failure. Compression therapy is used for venous leg ulcers and can decrease blood vessel diameter and pressure, which increases their effectiveness, preventing

neg: Vacuum aspiration Vacuum aspiration Vacuum or suction aspiration uses aspiration to remove uterine contents through the cervix. It may be used as a method of induced abortion, a therapeutic procedure used after miscarriage, or a procedure to obtain a sample for endometrial biopsy. The rate of infection is lower than any other surgical abortion procedure at 0.5%. Some sources may use the terms "dilation and evacuation" or "suction" "dilation and curettage" to refer to vacuum aspiration, although those terms are normally used to refer to distinct procedures. Vacuuming as a means of removing the uterine contents, rather than the previous use of

neg: Photomultiplier are used in numerous medical equipment designs. For example, blood analysis devices used by clinical medical laboratories, such as flow cytometers, utilize photomultipliers to determine the relative concentration of various components in blood samples, in combination with optical filters and incandescent lamps. An array of photomultipliers is used in a gamma camera. Photomultipliers are typically used as the detectors in flying-spot scanners. After 50 years, during which solid-state electronic components have largely displaced the vacuum tube, the photomultiplier remains a unique and important optoelectronic component. Perhaps its most useful quality is that it acts, electronically, as a nearly perfect current

neg: Kawashima procedure Glenn) results in much more than half the venous blood flow being diverted. After Kawashima, the only de-oxygenated blood returning to the heart is from the abdominal organs (via the hepatic veins)). As a result, there is much less hypoxia than after Glenn, and the heart is pumping less additional blood than after Glenn. However, the hypoxia can worsen over time (because of the development of microscopic AVMs in the lungs that allow blood to pass through without being oxygenated), and therefore these children still may need a complete Fontan procedure in the end. Kawashima procedure The Kawashima procedure is

neg: Hemothorax procedure called a tube thoracostomy. Generally, the thoracostomy tube is placed between the ribs in the sixth or seventh intercostal space at the mid-axillary line. Usually the lung will expand and the bleeding will stop after a chest tube is inserted. The blood in the chest can thicken as the clotting cascade is activated when the blood leaves the blood vessels and comes into contact with the pleural surface, injured lung or chest wall, or with the chest tube. As the blood thickens, it can clot in the pleural space (leading to a retained hemothorax) or within the chest tube,

neg: Senning procedure inferior and superior venae cavae to the mitral valve and therefore to the pulmonary circulation This is accomplished by creating a systemic venous conduit that channels deoxygenated blood from the superior and inferior vena cava towards the mitral valve. After this complex plastic reconstruction using flaps from the right atrial tissue and the interatrial septum and lets the oxygenated pulmonary venous blood flow to the tricuspid valve and from there to the systemic circulation. The anatomic left ventricle continues to pump into the pulmonary circulation and the anatomic right ventricle will work as the systemic pump, in other words the

neg: Hypoplastic left heart syndrome oxygenated blood in the right ventricle, there is still venous mixing from the lower half of the body, leading to some degree of oxygen desaturation. The final procedure, the Fontan procedure, completes the repair of the hypoplastic left heart. Although there are several variations, the functional effect is to redirect venous blood from the lower body (through the inferior vena cava) away from the right atrium to the pulmonary artery. This should eliminate any mixing of oxygenated and deoxygenated blood in the right ventricle. The right ventricle performs the traditional job of the left, supplying the body with oxygenated blood,

neg: Vacutainer Vacutainer A Vacutainer blood collection tube is a sterile glass or plastic test tube with a colored rubber stopper creating a vacuum seal inside of the tube, facilitating the drawing of a predetermined volume of liquid. Vacutainer tubes may contain additives designed to stabilize and preserve the specimen prior to analytical testing. Tubes are available with a safety-engineered stopper, with a variety of labeling options and draw volumes. The color of the top indicates the additives in the vial. Vacutainer tubes were invented by Joseph Kleiner and Becton Dickinson in 1949. "Vacutainer" is a registered trademark of Becton Dickinson, which

neg: Central venous catheter into the device for long term securement. Central venous catheter A central venous catheter (CVC), also known as a central line, central venous line, or central venous access catheter, is a catheter placed into a large vein. Catheters can be placed in veins in the neck (internal jugular vein), chest (subclavian vein or axillary vein), groin (femoral vein), or through veins in the arms (also known as a PICC line, or peripherally inserted central catheters). It is used to administer medication or fluids that are unable to be taken by mouth or would harm a smaller peripheral vein, obtain blood

neg: Ultrasonography of chronic venous insufficiency of the legs Attention will be focused on the direction of the blood flow in both of the venous systems, and in the perforator veins, as well as being focused on shunt detection. A shunting of blood from the thigh veins back into the lower leg veins will give a reflux situation. The veins most often found to be incompetent are the saphenous veins and the perforators communicating with the deep veins of the thigh. Venous ultrasonography of the lower limbs is the most demanding of the medical complementary examinations. It is dependent on the examiner's expertise and training, and the interpretation of

neg: Stenberg v. Carhart "partial birth abortion", which it defined as any abortion in which the physician "partially delivers vaginally a living unborn child before killing the unborn child and completing the delivery." The most common type of abortion performed is suction-aspiration abortion which consists of a vacuum tube inserted into the uterus; others consist of what is known as "D&E" (dilation and evacuation), which is usually used during the second trimester because of the increased amount of fetal material. The procedure dilates the cervix and removes some fetal material with non-vacuum instruments, and, in some cases, uses curettage inside the uterus so that

neg: Leukapheresis the word with an "-o-" as "*leukopheresis"; nonetheless, no professionally curated dictionaries as of 2016 enter that spelling, and it is traditionally treated as a misspelling by medical style guides that mention it. Leukapheresis Leukapheresis is a laboratory procedure in which white blood cells are separated from a sample of blood. It is a specific type of apheresis, the more general term for separating out one particular constituent of blood and returning the remainder to the circulation. Leukapheresis may be performed to decrease a very high white blood cell count, to obtain autologous (i.e., the patient's own) blood cells for

neg: Blood irradiation therapy sources. It is used only for ultraviolet blood irradiation, that involves drawing blood out through a vein and irradiating it outside of the body. Though promoted as a treatment for cancer, a 1952 review in the "Journal of the American Medical Association" and another review by the American Cancer Society in 1970 concluded the treatment was ineffective. Stephen Barrett, writing for Quackwatch, lists ultraviolet blood irradiation therapy as a questionable treatment. Blood irradiation therapy Blood irradiation therapy is a procedure in which the blood is exposed to low level red light (often laser light) for therapeutic reasons. Most research on

neg: Tracheotome Tracheotome A tracheotome is a medical instrument used to perform an incision in the trachea with a cutting blade operated by a powered cannula. It is often called a tracheostomy tube because once it enters the stoma in the trachea, a breathing tube is connected to a ventilator and oxygen is provided to the lungs. There are different types of tracheotomes. They can be made of metal, plastic or silicone. Plastic and silicone are widely used since they reduce the complications from the tracheotomy procedure such as subglottic stenosis and erosion of large blood vessels. The tracheostomy procedure is an

neg: Vascular remodelling in the embryo then undergo a process called lumenization, the spontaneous rearrangement of endothelial cells from a solid cord into a hollow tube. Inside the embryo, the dorsal aorta forms and eventually connect the heart to the capillary plexus of the yolk sac. This forms a closed-loop system of rigid endothelial tubing. It is known that even this early in the process of vasculogenesis, before the onset of blood flow, sections of the tube system may express ephrins or neuropilins, genetic markers of arterial or venous identities, respectively. These identities are still somewhat flexible, but the initial characterization is important to the embryonic

neg: Sven Ivar Seldinger Seldinger received an honorary doctorate from the Faculty of Medicine at Uppsala University, Sweden. Seldinger died at home in Dalecarlia, Sweden on 21 February 1998. He is survived by his wife and three daughters. The Seldinger technique is a medical procedure to obtain safe access to blood vessels and other hollow organs. It is used for angiography, insertion of chest drains and central venous catheters, insertion of PEG tubes using the push technique, insertion of the leads for an artificial pacemaker or implantable cardioverter-defibrillator, and numerous other interventional medical procedures. Seldinger first published this technique for obtaining percutaneous access to

neg: Venous cutdown Venous cutdown Venous cutdown is an emergency procedure in which the vein is exposed surgically and then a cannula is inserted into the vein under direct vision. It is used to get vascular access in trauma and hypovolemic shock patients when peripheral cannulation is difficult or impossible. The saphenous vein is most commonly used. This procedure has fallen out of favor with the development of safer techniques for central venous catheterization such as the Seldinger technique, the modified Seldinger technique, intraosseous infusion, as well as the use of ultrasound guidance for placement of central venous catheters without using the cutdown

neg: Impedance phlebography flow, causing the venous blood pressure to rise until it equals the pressure under the cuff. When the cuff is released there is a rapid venous runoff and a prompt return to the resting blood volume. Venous thrombosis will alter the normal response to temporary venous obstruction in a highly characteristic way, causing a delay in emptying of the venous system after the release of the tourniquet. The increase in blood volume after cuff inflation is also usually diminished. Impedance phlebography Impedance phlebography, or impedance plethysmography (IPG), is a non-invasive medical test that measures small changes in electrical resistance of

neg: Fontan procedure — but in many cases it can result in normal or near-normal growth, development, exercise tolerance, and good quality of life. However, in 20–30% of cases, patients will eventually require heart transplantation and given the long-term consequences of chronic venous hypertension and insidious organ damage, freedom from morbidity is unlikely in the long term. Fontan procedure The Fontan procedure or Fontan–Kreutzer procedure is a palliative surgical procedure used in children with univentricular hearts. It involves diverting the venous blood from the inferior vena cava (IVC) and superior vena cava (SVC) to the pulmonary arteries without passing through the morphologic right

neg: Dissolved gas analysis extraction and based on Toepler principle. In this apparatus a fixed volume of sample oil is directly drawn from a sample tube into a degassing vessel under vacuum, where the gases are released. These gases are isolated using a mercury piston to measure its volume at atmospheric pressure and subsequent transfer to a gas chromatograph using a gas-tight syringe. An apparatus, in very similar design and in principle providing a multiple gas extraction, using vacuum and Toepler pump has been in service in Sydney (Australia) for more than 30 years. The system is in use for power and instrument transformers,

neg: Pelvic congestion syndrome the "Gold Standard" test for pelvic venous reflux. The same research group has shown that the size of the veins - as shown by venography and also used as the diagnostic criteria in CT and MRI - is not relevant and only Transvaginal Duplex Ultrasound shows the venous reflux that causes the problem. Early treatment options include pain medication using nonsteroidal anti-inflammatory drugs, suppression of ovarian function, and alternative therapies such as physical therapy. The surgical option involves stopping blood flow to the varicose veins using noninvasive surgical techniques such as a procedure called embolization. The procedure requires an overnight

neg: Central venous catheter minimize risks and complications of the procedure. Next, the area of skin over the planned insertion site is cleaned. A local anesthetic is applied if necessary. The location of the vein is identified by landmarks or with the use of a small ultrasound device. A hollow needle is advanced through the skin until blood is aspirated. The color of the blood and the rate of its flow help distinguish it from arterial blood (suggesting that an artery has been accidentally punctured). Within North American and Europe, ultrasound use now represents the gold standard for central venous access and skills, with

neg: Hemodialysis a tube at a rate of 200–400 mL/min. The tube is connected to a 15, 16, or 17 gauge needle inserted in the dialysis fistula or graft, or connected to one port of a dialysis catheter. The blood is then pumped through the dialyzer, and then the processed blood is pumped back into the patient's bloodstream through another tube (connected to a second needle or port). During the procedure, the patient's blood pressure is closely monitored, and if it becomes low, or the patient develops any other signs of low blood volume such as nausea, the dialysis attendant can administer

neg: Skin grafting works by placing a section of foam cut to size over the wound, then laying a perforated tube onto the foam. The arrangement is then secured with bandages. A vacuum unit then creates negative pressure, sealing the edges of the wound to the foam, and drawing out excess blood and fluids. This process typically helps to maintain cleanliness in the graft site, promotes the development of new blood vessels, and increases the chances of the graft successfully taking. NPWT can also be used between debridement and graft operations to assist an infected wound in remaining clean for a period of

neg: Tube drawing otherwise it will give inadequate results. This process is often used for oil-well tubing. Tethered plug drawing, also known as semi-floating mandrel drawing, is a mix between floating plug drawing and fixed plug drawing. The mandrel is allowed to float, but it still anchored via a tether. This process gives similar results to the floating plug process, except that it is designed for straight tubes. It gives a better inner surface finish than rod drawing. Tube drawing Tube drawing is a process to size a tube by shrinking a large diameter tube into a smaller one, by drawing the tube

neg: Central venous catheter Central venous catheter A central venous catheter (CVC), also known as a central line, central venous line, or central venous access catheter, is a catheter placed into a large vein. Catheters can be placed in veins in the neck (internal jugular vein), chest (subclavian vein or axillary vein), groin (femoral vein), or through veins in the arms (also known as a PICC line, or peripherally inserted central catheters). It is used to administer medication or fluids that are unable to be taken by mouth or would harm a smaller peripheral vein, obtain blood tests (specifically the "central venous oxygen saturation"),

neg: Impedance phlebography Impedance phlebography Impedance phlebography, or impedance plethysmography (IPG), is a non-invasive medical test that measures small changes in electrical resistance of the chest, calf or other regions of the body. These measurements reflect blood volume changes, and can indirectly indicate the presence or absence of venous thrombosis. This procedure provides an alternative to venography, which is invasive and requires a great deal of skill to execute adequately and interpret accurately. For the chest, the technique was developed by NASA to measure the split second impedance changes within the chest, as the heart beats, to calculate both cardiac output and lung

neg: Vacutainer manufactures and sells the tubes today. Vacutainer needle are double ended, with one side being encased in a thin rubber coating for safety. When the needle is screwed into the translucent plastic needle holder, the rubber needle is inside the holder, and the exposed needle will be inserted into the vein. When a Vacutainer tube is inserted into the holder, its rubber cap is punctured by the inner needle and the vacuum in the tube pulls blood through the needle and into the tube. The filled tube is then removed and another can be inserted and filled the same way.

neg: Loa loa filariasis into first-stage larvae and subsequently into third-stage infective larvae. The third-stage infective larvae migrate to the fly's proboscis and can infect another human when the fly takes a blood meal. Identification of microfilariae by microscopic examination is a practical diagnostic procedure. Examination of blood samples will allow identification of microfilariae of "Loa loa". It is important to time the blood collection with the known periodicity of the microfilariae (between 10 am and 2 pm). The blood sample can be a thick smear, stained with Giemsa or haematoxylin and eosin (see staining). For increased sensitivity, concentration techniques can be used. These

neg: Catheter your kidneys fail (Stage 5 Kidney Disease) and can no longer clean your blood and remove extra fluid from your body. A hemodialysis access or vascular access is a way to reach your blood for hemodialysis. (National Kidney Foundation) Catheter In medicine, a catheter is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. By modifying the material or adjusting the way catheters are manufactured, it is possible to tailor catheters for cardiovascular, urological, gastrointestinal, neurovascular,

neg: Hydrolysable tannin used as a standard and the data are based on experiments carried out in triplicate. 10 mg of samples tannin in 1 ml 2N HSO are put into constricted test tubes and frozen. The tubes are vacuum-waled and heated for 24 hours at 100 °C. Tubes were cooled, opened and the filtered content made up to 10 ml with pyridine. Then 1.1 ml of pyridine and l ml of sample are mixed in a dry test tube. After adding 0.10 ml of concentrated HCl and mixing, the sample is brought to 30 °C. The sample is quickly mixed after 0.10

neg: Venipuncture (incision into a vein) is also the treatment of certain diseases such as hemochromatosis and primary and secondary polycythemia. There are many ways in which blood can be drawn from a vein. The best method varies with the age of the patient, equipment available and tests required. Most blood collection in the US, UK, Canada and Hong Kong is done with an evacuated tube system, (two common systems are Vacutainer (Becton, Dickinson and company) and Vacuette (Greiner Bio-One). The equipment consists of a plastic adapter, a.k.a. tube or needle holder/ hub, a hypodermic needle and a vacuum tube. Under certain

neg: Venous cutdown perforation of the posterior wall of the vein, venous thrombosis and nerve and arterial transection. This procedure can result in damage to the saphenous nerve due to its intimate path with the great saphenous vein, resulting in loss of cutaneous sensation in the medial leg. Over the years, the venous cutdown procedure has become outdated by the introduction and recent prehospital developments of intraosseous infusion in trauma/hypovolemic shock patients. Venous cutdown Venous cutdown is an emergency procedure in which the vein is exposed surgically and then a cannula is inserted into the vein under direct vision. It is used to

neg: Percutaneous blood vessel. This technique is known as the modified Seldinger technique. More generally, "percutaneous", via its Latin roots means, 'by way of the skin'. An example would be percutaneous drug absorption from topical medications. More often, percutaneous is typically used in reference to placement of medical devices using a needle stick approach. In general, percutaneous refers to the access modality of a medical procedure, whereby a medical device is introduced into a patient's blood vessel via a needle stick. This is commonly known as the Seldinger technique named after Sven Ivar Seldinger. The technique involves placing a needle through the

neg: Gouy balance a cylindrical container such as a test tube. Solid compounds are generally ground into a fine powder to allow for uniformity amongst the sample. The sample is suspended between the magnetic poles through an attached thread or string. The experimental procedure requires two separate reading to be performed. An initial balance reading is performed on the sample of interest without a magnetic field (m ). A subsequent balance reading is taken with an applied magnetic field (m). The difference between these two readings relates to the magnetic force on the sample (m – m). The apparent change in mass from

neg: Vacuum tube Vacuum tube In electronics, a vacuum tube, an electron tube, or valve (British usage) or, colloquially, a tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a thermionic tube or thermionic valve uses the phenomenon of thermionic emission of electrons from a heated cathode and is used for a number of fundamental electronic functions such as signal amplification and current rectification. Non-thermionic types, such as a vacuum phototube however, achieve electron emission through the photoelectric effect, and are used

neg: Chronic venous insufficiency guided, minimally invasive surgery strategic for the treatment of varicose veins, performed under local anaesthetic. CHIVA is an abbreviation from the French "Cure Conservatrice et Hemodynamique de l'Insufficience Veineuse en Ambulatoire". Surgical treatment of CVI attempts a cure by physically changing the veins with incompetent valves. Surgical treatments for CVI include the following: Chronic venous insufficiency Chronic venous insufficiency (CVI) is a medical condition in which blood pools in the veins, straining the walls of the vein. The most common cause of CVI is superficial venous reflux which is a treatable condition. As functional venous valves are required to provide

neg: Ion source similar to MALDI in sample preparation, but a laser is not required to convert analyte molecules included in a matrix compound into gas-phase ions. In MAI, analyte ions have charge states similar to electrospray ionization but obtained from a solid matrix rather than a solvent. No voltage or laser is required, but a laser can be used to obtain spatial resolution for imaging. Matrix-analyte samples are ionized in the vacuum of a mass spectrometer and can be inserted into the vacuum through an atmospheric pressure inlet. Less volatile matrices such as 2,5-dihydroxybenzoic acid require a hot inlet tube to produce

neg: Heart development neural plate. The growth of the brain and the cephalic folds push the oropharyngeal membrane forward, while the heart and the pericardial cavity move first to the cervical region and then into the chest. The curved portion of the horseshoe-shaped area expands to form the future ventricular infundibulum and the ventricular regions, as the heart tube continues to expand. The tube starts receiving venous drainage in its caudal pole and will pump blood out of the first aortic arch and into the dorsal aorta through its polar head. Initially the tube remains attached to the dorsal part of the pericardial

neg: Vacuum tube in field emission display technology, but there were significant production problems. As of 2014, NASA's Ames Research Center was reported on working on vacuum-channel transistors produced using CMOS techniques. Vacuum tube In electronics, a vacuum tube, an electron tube, or valve (British usage) or, colloquially, a tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a thermionic tube or thermionic valve uses the phenomenon of thermionic emission of electrons from a heated cathode and is used for a number

neg: Percutaneous umbilical cord blood sampling reached and the correct position of the needle is confirmed, the fetal blood is drawn. The needle is removed after all necessary samples are taken. The site of puncture is monitored after the procedure for bleeding. Also, if the fetus is viable, fetal heart rate is monitored post-procedure for one to two hours. After the blood samples are obtained, they are placed into tubes containing anticoagulants in order to stop the blood from clotting. If the blood sample was obtained at the site close to the placenta, a fetal blood confirmation test should be done to ensure no mixing of

neg: Bismuth telluride many natural bismuth tellurides of different stoichiometry, as well as compounds of the Bi-Te-S-(Se) system, like BiTeS (tetradymite). Bismuth telluride is prepared by sealing a sample of bismuth and tellurium metal in a quartz tube under vacuum (critical, as an unsealed or leaking sample may explode in a furnace) and heating it to 800 °C in a muffle furnace. Bismuth telluride Bismuth telluride (BiTe) is a gray powder that is a compound of bismuth and tellurium also known as bismuth(III) telluride. It is a semiconductor, which, when alloyed with antimony or selenium, is an efficient thermoelectric material for refrigeration or

neg: Deep vein thrombosis strong risk factor of older age, which alters blood composition to favor clotting. Other important acquired risk factors include major surgery and trauma, both of which may increase the risk because of tissue factor from outside the vascular system entering the blood. In orthopedic surgery, venous stasis may be temporarily provoked by a cessation of blood flow as part of the procedure. Cancer can grow in and around veins, causing venous stasis, and can also stimulate increased levels of tissue factor. Pregnancy causes blood to favor clotting, and in the postpartum, placental tearing releases substances that favor clotting. Oral contraceptives

neg: Ultrasonography of chronic venous insufficiency of the legs good specificity and sensitivity capability of this technique, enabling the possibility of properly seeing the superficial tissues. Hemodynamic study began in France in 1977, when Claude Franceschi, published the very first book in the world on Vascular Doppler Exploration (Vascular investigation by Doppler ultrasound) . In 1988, he first described the conservative treatment for venous insufficiency, known as CHIVA. also translated into English and Italian. Ultrasonography of chronic venous insufficiency of the legs Ultrasonography of suspected or previously confirmed chronic venous insufficiency of leg veins is a risk-free, non-invasive procedure. It gives information about the anatomy, physiology and pathology of

neg: Pancreatitis pancreatitis is based on a threefold increase in the blood of either amylase or lipase. In chronic pancreatitis these tests may be normal. Medical imaging such as ultrasound and CT scan may also be useful. Acute pancreatitis is usually treated with intravenous fluids, pain medication, and sometimes antibiotics. Typically eating and drinking are disallowed, and a nasogastric tube is placed in the stomach. A procedure known as an endoscopic retrograde cholangiopancreatography (ERCP) may be done to examine the distal common bile duct and remove a gallstone if present. In those with gallstones the gallbladder is often also removed. In chronic

neg: Arachnoid granulation sinuses as well. Diffusion across the arachnoid granulations into the superior sagittal sinus returns CSF to the venous circulation. The arachnoid granulations act as one-way valves. Normally the pressure of the CSF is higher than that of the venous system, so CSF flows through the villi and granulations into the blood. If the pressure is reversed for some reason, fluid will not pass back into the subarachnoid space. The reason for this is not known. It has been suggested that the endothelial cells of the venous sinus create vacuoles of CSF, which move through the cell and out into the

neg: Arterial blood gas test may need to be heparinised, by drawing up a small amount of liquid heparin and squirting it out again to remove air bubbles. Once the sample is obtained, care is taken to eliminate visible gas bubbles, as these bubbles can dissolve into the sample and cause inaccurate results. The sealed syringe is taken to a blood gas analyzer. If a plastic blood gas syringe is used, the sample should be transported and kept at room temperature and analyzed within 30 min. If prolonged time delays are expected (i.e., greater than 30 min) prior to analysis, the sample should be drawn

neg: Venous blood Venous blood Venous blood is deoxygenated blood which travels from the peripheral vessels, through the venous system into the right atrium of the heart. Deoxygenated blood is then pumped by the right ventricle to the lungs via the pulmonary artery which is divided in two branches, left and right to the left and right lungs respectively. Blood is oxygenated in the lungs and returns to the left atrium through the pulmonary veins. Venous blood is typically colder than arterial blood, and has a lower oxygen content and pH. It also has lower concentrations of glucose and other nutrients, and has

neg: Fontan procedure Fontan procedure The Fontan procedure or Fontan–Kreutzer procedure is a palliative surgical procedure used in children with univentricular hearts. It involves diverting the venous blood from the inferior vena cava (IVC) and superior vena cava (SVC) to the pulmonary arteries without passing through the morphologic right ventricle; i.e., the systemic and pulmonary circulations are placed in series with the functional single ventricle. It was initially described in 1971 by Dr. Francois Marie Fontan (1929–2018) from Bordeaux, France, and by Dr. Guillermo Kreutzer from Buenos Aires, Argentina (b. 1934) separately as a surgical treatment for tricuspid atresia. The Fontan procedure is

neg: X-ray tube the increased power density level for the metal-jet X-ray tube is the possibility to operate with a smaller focal spot, say 5 µm, to increase image resolution and at the same time acquire the image faster, since the power is higher (15-30 W) than for solid-anode tubes with 10 µm focal spots. As with any vacuum tube, there is a cathode, which emits electrons into the vacuum and an anode to collect the electrons, thus establishing a flow of electrical current, known as the beam, through the tube. A high voltage power source, for example 30 to 150 kilovolts (kV),

neg: Aspirator (medical device) were used such as "Potain's aspirator". Aspirator (medical device) A medical aspirator is a suction machine used to remove mucus, blood, and other bodily fluids from a patient. They can be used during surgical procedures but an operating theater is generally equipped with a central system of vacuum tubes. Most aspirators are therefore portable, for use in ambulances and nursing homes, and can run on AC/DC or battery power. They consist of a vacuum pump, a vacuum regulator and gauge, a collection canister, and sometimes a bacterial filter. Plastic tubing is used to continuously draw fluid into the collection canister.

neg: Chromatography in one direction, the solvent entry in the opposite direction, whilst changing the analyte and waste takeoff positions appropriately as well. Pyrolysis–gas chromatography–mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. Pyrolysis is the thermal decomposition of materials in an inert atmosphere or a vacuum. The sample is put into direct contact with a platinum wire, or placed in a quartz sample tube, and rapidly heated to 600–1000 °C. Depending on the application even higher temperatures are used.