[转帖]输液泵相关背景知识--英文

Infusion pump

A type of infusion pump, manufactured by Fresenius.

An infusion pump infuses fluids, medication or nutrients into a patient's circulatory system. It is generally used intravenously, although subcutaneous, arterial and epidural infusions are occasionally used.

Infusion pumps can administer fluids in ways that would be impractically expensive or unreliable if performed manually by nursing staff. For example, they can administer as little as 0.1 mL per hour injections (too small for a drip), injections every minute, injections with repeated boluses requested by the patient, up to maximum number per hour (e.g. in patient-controlled analgesia), or fluids whose volumes vary by the time of day.

Because they can also produce quite high but controlled pressures, they can inject controlled amounts of fluids subcutaneously (beneath the skin), or epidurally (just within the surface of the central nervous system- a very popular local spinal anesthesia for childbirth).

Contents   1 Types of infusion 2 Types of pump 3 Safety features available on some pumps 4 See also

 Types of infusion

The user interface of pumps usually requests details on the type of infusion from the technician or nurse that sets them up:

• Continuous infusion usually consists of small pulses of infusion, usually between 500 nanoliters and 10000 microliters, depending on the pump's design, with the rate of these pulses depending on the programmed infusion speed.
• Intermittent infusion has a "high" infusion rate, alternating with a low programmable infusion rate to keep the cannula open. The timings are programmable. This mode is often used to administer antibiotics, or other drugs that can irritate a blood vessel.
• Patient-controlled is infusion on-demand, usually with a preprogrammed ceiling to avoid intoxication. The rate is controlled by a pressure pad or button that can be activated by the patient. It is the method of choice for patient-controlled analgesia (PCA), in which repeated small doses of opioid analgesics are delivered, with the device coded to stop administration before a dose that may cause hazardous respiratory depression is reached.
• Total parenteral nutrition usually requires an infusion curve similar to normal mealtimes.

Some pumps offer modes in which the amounts can be scaled or controlled based on the time of day. This allows for circadian cycles which may be required for certain types of medication.

 Types of pump

A Baxter International Colleague CX infusion pump

There are two basic classes of pumps. Large volume pumps can pump nutrient solutions large enough to feed a patient. Small-volume pumps infuse hormones, such as insulin, or other medicines, such as opiates.

Within these classes, some pumps are designed to be portable, others are designed to be used in a hospital, and there are special systems for charity and battlefield use.

Large-volume pumps usually use some form of peristaltic pump. Classically, they use computer-controlled rollers compressing a silicone-rubber tube through which the medicine flows. Another common form is a set of fingers that press on the tube in sequence.

Small-volume pumps usually use a computer-controlled motor turning a screw that pushes the plunger on a syringe.

The classic medical improvisation for an infusion pump is to place a blood pressure cuff around a bag of fluid. The battlefield equivalent is to place the bag under the patient. The pressure on the bag sets the infusion pressure. The pressure can actually be read-out at the cuff's indicator. The problem is that the flow varies dramatically with the patient's blood pressure (or weight), and the needed pressure varies with the administration route, making this quite risky for use by an untrained person. Pressures into a vein are usually less than 8 lbf/in² (55 kPa. Epidural and subcutaneous pressures are usually less than 18 lbf/in² (125 kPa).

Places that must provide the least-expensive care often use pressurized infusion systems. One common system has a purpose-designed plastic "pressure bottle" pressurized with a large disposable plastic syringe. A combined flow restrictor, air filter and drip chamber helps a nurse set the flow. The parts are reusable, mass-produced sterile plastic, and can be produced by the same machines that make plastic soft-drink bottles and caps. A pressure bottle, restrictor and chamber requires more nursing attention than electronically-controlled pumps. In the areas where these are used, nurses are often volunteers, or very inexpensive.

The restrictor and high pressure helps control the flow better than the improvised schemes because the high pressure through the small restrictor orifice reduces the variation of flow caused by patients' blood pressures.

An air filter is an essential safety device in a pressure infusor, to keep air out of the patients' veins: doctors estimate that 0.55 cm³ of air per kilogram of body weight is enough to kill (200-300 cm³ for adults) by filling the patient's heart. Small bubbles could cause harm in arteries, but in the veins they pass through the heart and leave in the patients' lungs. The air filter is just a membrane that passes gas but not fluid or pathogens. When a large air bubble reaches it, it bleeds off.

Some of the smallest infusion pumps use osmotic power. Basically, a bag of salt solution absorbs water through a membrane, swelling its volume. The bag presses medicine out. The rate is precisely controlled by the salt concentrations and pump volume. Osmotic pumps are usually recharged with a syringe.

Spring-powered clockwork infusion pumps have been developed, and are sometimes still used in veterinary work and for ambulatory small-volume pumps. They generally have one spring to power the infusion, and another for the alarm bell when the infusion completes.

Battlefields often have a need to perfuse large amounts of fluid quickly, with dramatically changing blood pressures and patient condition. Specialized infusion pumps have been designed for this purpose, although they have not been deployed.

Many infusion pumps are controlled by a small embedded system. They are carefully designed so that no single cause of failure can harm the patient. For example, most have batteries in case the wall-socket power fails. Additional hazards are uncontrolled flow causing an overdose, uncontrolled lack of flow, causing an underdose, reverse flow, which can siphon blood from a patient, and air in the line, which can starve a patient's tissues of oxygen if it floats to some part of a patient's body.

 Safety features available on some pumps

The range of safety features varies widely with the age and make of the pump. A state of the art pump in 2003^[update] may have the following safety features:

• Certified to have no single point of failure. That is, no single cause of failure should cause the pump to silently fail to operate correctly. It should at least stop pumping and make at least an audible error indication. This is a minimum requirement on all human-rated infusion pumps of whatever age. It is not required for veterinary infusion pumps.
• Batteries, so the pump can operate if the power fails or is unplugged.
• Anti-free-flow devices prevent blood from draining from the patient, or infusate from freely entering the patient, when the infusion pump is being set-up.
• A "down pressure" sensor will detect when the patient's vein is blocked, or the line to the patient is kinked. This may be configurable for high (subcutaneous and epidural) or low (venous) applications.
• An "air-in-line" detector. A typical detector will use an ultrasonic transmitter and receiver to detect when air is being pumped. Some pumps actually measure the volume, and may even have configurable volumes, from 0.1 to 2 ml of air. None of these amounts can cause harm, but sometimes the air can interfere with the infusion of a low-dose medicine.
• An "up pressure" sensor can detect when the bag or syringe is empty, or even if the bag or syringe is being squeezed.
• A drug library with customizable programmable limits for individual drugs that that helps to avoid medication errors.
• Mechanisms to avoid uncontrolled flow of drugs in large volume pumps (often in combination with a giving st based free flow clamp) and increasingly also in syringe pumps (piston-brake)
• Many pumps include an internal electronic log of the last several thousand therapy events. These are usually tagged with the time and date from the pump's clock. Usually, erasing the log is a feature protected by a security code, specifically to detect staff abuse of the pump or patient.
• Many makes of infusion pump can be configured to display only a small subset of features while they are operating, in order to prevent tampering by patients, untrained staff and visitors.

 See also

• Intravenous drip
• Pharmacy informatics
• Syringe driver
• Research Syringe Pump
• Total parenteral nutrition

Syringe driver

Various syringe pumps, manufactured by Chemyx syringe pump Inc.

A syringe driver or syringe pump is a small infusion pump, used to gradually administer small amounts of fluid (with or without medication) to a patient or for use in chemical and biomedical research.

The most popular use of syringe drivers is in palliative care, to continuously administer analgesics (painkillers), antiemetics (medication to suppress nausea and vomiting) and other drugs. This prevents periods during which medication levels in the blood are too high or too low, and avoids the use of multiple tablets (especially in people who have difficulty swallowing). As the medication is administered subcutaneously, the area for administration is practically limitless, although oedema may interfere with the action of some drugs.

Syringe drivers are also useful for delivering IV medications over several minutes. In the case of a medication which should be slowly pushed in over the course of several minutes, this device saves staff time and reduces errors.

 External links

• Picture of syringe driver in use

Peristaltic pump

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360 Degree Peristaltic Pump

Rotary peristaltic pump

Linear peristaltic pump

A peristaltic pump is a type of positive displacement pump used for pumping a variety of fluids. The fluid is contained within a flexible tube fitted inside a circular pump casing (though linear peristaltic pumps have been made). A rotor with a number of "rollers", "shoes" or "wipers" attached to the external circumference compresses the flexible tube. As the rotor turns, the part of tube under compression closes (or "occludes") thus forcing the fluid to be pumped to move through the tube. Additionally, as the tube opens to its natural state after the passing of the cam ("restitution") fluid flow is induced to the pump. This process is called peristalsis and used in many biological systems such as the gastrointestinal tract.

Contents   1 Applications 2 Variations 2.1 Hose pumps 2.2 Tube pumps 2.3 360 Degree eccentric design 3 Advantages 4 Tubing 5 Typical applications

 Applications

Peristaltic pumps are typically used to pump clean/sterile or aggressive fluids, because cross contamination cannot occur. Some common applications include pumping IV fluids through an infusion device, aggressive chemicals, high solids slurries and other materials where isolation of the product from the environment, and the environment from the product, are critical. The peristaltic pump is the standard method for introducing liquids into the nebulizer on an inductively coupled plasma mass spectrometry (ICP-MS) unit.

 Variations

 Hose pumps

Higher pressure peristaltic hose pumps which can typically operate against up to 16 bar, typically use shoes and have casings filled with lubricant to prevent abrasion of the exterior of the pump tube and to aid in the dissipation of heat, and use reinforced tubes, often called "hoses". This class of pump is often called a "hose pump".

 Tube pumps

Lower pressure peristaltic pumps, typically have dry casings and use rollers, use non-reinforced tubing. This class of pump is sometimes called a "tube pump" or "tubing pump".

 360 Degree eccentric design

A unique approach to peristaltic hose pump design employs a single oversized roller on an eccentric shaft that compresses an engineered, low friction hose through 360 degrees of rotation. The benefits of this design include more flow per revolution and only one compression and expansion per cycle. At equal performance points this pump runs more slowly, with consequent longer hose lifetime, than pumps with multiple shoes or rollers.

Many older hose pumps use shoes to compress the hose. When the shoe slides over the outside of the hose, it creates friction and heat, which shortens hose life. A single roller pump uses a large diameter lubricated roller on an eccentric shaft that rolls over the hose. This means that it produces less friction, and therefore less heat, than a pump with shoes.

In addition to less heat, an eccentric shaft hose pump functions with only a single compression of the hose per revolution. For every one rotation, the pump has one compression of the hose, while pumps with multiple shoes or rollers have at least two compressions per revolution, and in some cases three or four. Since the hose is the heart of a peristaltic hose pump, and hose life is inversely proportional to the number of squeezes, this design will outperform a pump with shoes at the same speed.

The hose in this type of pump takes up the full 360 degrees of the pump housing. This is important, because at an equal size, this design will produce 55% more flow at the same speed. This means that one can get more flow at the same pump speed, or run the pump more slowly to generate the same flow.

 Advantages

Because the only part of the pump in contact with the fluid being pumped is the interior of the tube, it is easy to sterilize and clean the inside surfaces of the pump. Furthermore, since there are no moving parts in contact with the fluid, peristaltic pumps are inexpensive to manufacture. Their lack of valves, seals and glands makes them comparatively inexpensive to maintain, and the use of a hose or tube makes for a relatively low-cost maintenance item compared to other pump types. Peristaltic pumps also minimize shear forces experienced by the fluid, which may help to keep colloids and slurry fluids from separating.^{[citation needed]}

 Tubing

It is important to select tubing with appropriate chemical resistance towards the liquid being pumped. Types of tubing commonly used in peristaltic pumps include:

• Polyvinyl chloride (PVC)
• Silicone rubber
• Fluoropolymer

Trade names include Tygon, Viton, Pharmed, Norprene, Marprene, Bioprene, Sta-Pure, Chem-Sure, Neoprene, Fluorel, Pumpsil-D and Pumpsil.

Example of tube being changed on a peristaltic pump. [1]

 Typical applications

• Dialysis machines
• Open-heart bypass pump machines
• Infusion pump
• AutoAnalyzer
• Sewage sludge
• Aquariums, particularly calcium reactors
• Analytical chemistry experiments
• Carbon monoxide monitors (e.g., at Longannet power station)
• Agriculture
• Food manufacturing
• Beverage dispensing
• Chemical
• Engineering
• Construction - pumping cement
• Pharmaceutical production
• OEM applications
• Print and packaging
• Paint and pigments
• Pulp and paper
• Science and research
• Water and Waste
• 'Sapsucker' pumps to apply vacuum to maple trees to enhance sap extraction and pump the sap to the evaporator

Circulatory system

The human circulatory system. Red indicates oxygenated blood, blue indicates deoxygenated.

The circulatory system is an organ system that passes nutrients (such as amino acids and electrolytes), gases, hormones, blood cells, nitrogen waste products, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis. This system may be seen strictly as a blood distribution network, but some consider the circulatory system as composed of the cardiovascular system, which distributes blood, and the lymphatic system, which distributes lymph. While humans, as well as other vertebrates, have a closed cardiovascular system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open cardiovascular system. The most primitive animal phyla lack circulatory system. The lymphatic system, on the other hand, is an open system.

The main components of the human circulatory system are the heart, the blood, and the blood vessels. The circulatory system includes: the pulmonary circulation, a "loop" through the lungs where blood is oxygenated; and the systemic circulation, a "loop" through the rest of the body to provide oxygenated blood. An average adult contains five to six quarts (roughly 4.7 to 5.7 liters) of blood, which consists of plasma, red blood cells, white blood cells, and platelets. Also, the digestive system works with the circulatory system to provide the nutrients the system needs to keep the heart pumping.

Two types of fluids move through the circulatory system: blood and lymph. The blood, heart, and blood vessels form the cardiovascular system. The lymph, lymph nodes, and lymph vessels form the lymphatic system. The cardiovascular system and the lymphatic system collectively make up the circulatory system.

Contents   1 Pulmonary circulation 2 Systemic circulation 3 Coronary circulation 4 Heart 5 Closed cardiovascular system 6 Other vertebrates 7 Open circulatory system 8 Absence of circulatory system 9 Measurement techniques 10 Health and disease 11 Oxygen transportation 12 History of discovery 13 Other images 14 See also 15 References 16 External links

 Pulmonary circulation

Main article: Pulmonary circulation

Pulmonary circulation is the portion of the cardiovascular system which transports oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart.

Oxygen deprived blood from the vena cava enters the right atrium of the heart and flows through the tricuspid valve into the right ventricle where it is pumped through the pulmonary semilunar valve into the pulmonary arteries which go to the lungs. Pulmonary veins return the now oxygen-rich blood to the heart, where it enters the left atrium before flowing through the mitral valve into the left ventricle. Also, from the left ventricle the oxygen-rich blood is pumped out via the aorta, and on to the rest of the body.

 Systemic circulation

Main article: Systemic circulation

Systemic circulation is the portion of the cardiovascular system which transports oxygenated blood away from the heart, to the rest of the body, and returns oxygen-depleted blood back to the heart. Systemic circulation is, distance-wise, much longer than pulmonary circulation, transporting blood to every part of the body except the lungs.

 Coronary circulation

Main article: Coronary circulation

The coronary circulatory system provides a blood supply to the heart. As it provides oxygenated blood to the heart, it is by definition a part of the systemic circulatory system.

 Heart

View from the front, which means the right side of the heart is on the left of the diagram (and vice-versa)

Main article: heart

The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs. In the human heart there is one atrium and one ventricle for each circulation, and with both a systemic and a pulmonary circulation there are four chambers in total: left atrium, left ventricle, right atrium and right ventricle. The right Atrium, which is the upper chamber of the right side. The blood that is returned to the right atrium is deoxygenated (poor in oxygen) and passed into the right ventricle to be pumped through the pulmonary artery to the lungs for re-oxygenation and removal of carbon dioxide. The left atrium receives newly oxygenated blood from the lungs as well as the pulmonary vein which is passed into the strong left ventricle to be pumped through the aorta to the tissues of the body.

 Closed cardiovascular system

The cardiovascular systems of humans are closed, meaning that the blood never leaves the system. In contrast, oxygen and nutrients diffuse across the blood vessel layers and enters interstitial fluid, which carries oxygen and nutrients to the target cells, and carbon dioxide and wastes in the opposite direction. The other component of the circulatory system, the lymphatic system, is not closed.

 Other vertebrates

The circulatory systems of all vertebrates, as well as of annelids (for example, earthworms) and cephalopods (squid and octopus) are closed, just as in humans. Still, the systems of fish, amphibians, reptiles, and birds show various stages of the evolution of the circulatory system.

In fish, the system has only one circuit, with the blood being pumped through the capillaries of the gills and on to the capillaries of the body tissues. This is known as single cycle circulation. The heart of fish is therefore only a single pump (consisting of two chambers). In amphibians and most reptiles, a double circulatory system is used, but the heart is not always completely separated into two pumps. Amphibians have a three-chambered heart.

In reptiles, the ventricular septum of the heart is incomplete and the pulmonary artery is equipped with a sphincter muscle. This allows a second possible route of blood flow. Instead of blood flowing through the pulmonary artery to the lungs, the sphincter may be contracted to divert this blood flow through the incomplete ventricular septum into the left ventricle and out through the aorta. This means the blood flows from the capillaries to the heart and back to the capillaries instead of to the lungs. This process is useful to ectothermic (cold-blooded) animals in the regulation of their body temperature.

Birds and mammals show complete separation of the heart into two pumps, for a total of four heart chambers; it is thought that the four-chambered heart of birds evolved independently from that of mammals.

 Open circulatory system

The Open Circulatory System is a system in which fluid (called hemolymph) in a cavity called the hemocoel bathes the organs directly with oxygen and nutrients and there is no distinction between blood and interstitial fluid; this combined fluid is called hemolymph or haemolymph. Muscular movements by the animal during locomotion can facilitate hemolymph movement, but diverting flow from one area to another is limited. When the heart relaxes, blood is drawn back toward the heart through open-ended pores (ostia).

Hemolymph fills all of the interior hemocoel of the body and surrounds all cells. Hemolymph is composed of water, inorganic salts (mostly Na⁺, Cl^-, K⁺, Mg²⁺, and Ca²⁺), and organic compounds (mostly carbohydrates, proteins, and lipids). The primary oxygen transporter molecule is hemocyanin.

There are free-floating cells, the hemocytes, within the hemolymph. They play a role in the arthropod immune system.

 Absence of circulatory system

Circulatory systems are absent in some animals, including flatworms (phylum Platyhelminthes). Their body cavity has no lining or enclosed fluid. Instead a muscular pharynx leads to an extensively branched digestive system that facilitates direct diffusion of nutrients to all cells. The flatworm's dorso-ventrally flattened body shape also restricts the distance of any cell from the digestive system or the exterior of the organism. Oxygen can diffuse from the surrounding water into the cells, and carbon dioxide can diffuse out. Consequently every cell is able to obtain nutrients, water and oxygen without the need of a transport system.

Some animals, such as jellies, have more extensive branching from their gastrovascular cavity (which functions as both a place of digestion and a form of circulation), this branching allows for bodily fluids to reach the outter layers, since the digestion begins in the inner layers.

 Measurement techniques

• Electrocardiogram — for cardiac electrophysiology
• Sphygmomanometer and stethoscope — for blood pressure
• Pulse meter — for cardiac function (heart rate, rhythm, dropped beats)
• Pulse — commonly used to determine the heart rate in absence of certain cardiac pathologies
• Heart rate variability -- used to measure variations of time intervals between heart beats
• Nail bed blanching test — test for perfusion
• Vessel cannula or catheter pressure measurement — pulmonary wedge pressure or in older animal experiments.

 Health and disease

Main article: Cardiovascular disease

Main article: Congenital heart defect

 Oxygen transportation

Main article: Blood#Oxygen transport

About 98.5% of the oxygen in a sample of arterial blood in a healthy human breathing air at sea-level pressure is chemically combined with haemoglobin molecules. About 1.5% is physically dissolved in the other blood liquids and not connected to Hgb. The haemoglobin molecule is the primary transporter of oxygen in mammals and many other species.

 History of discovery

The earliest known writings on the circulatory system are found in the Ebers Papyrus (16th century BCE), an ancient Egyptian medical papyrus containing over 700 prescriptions and remedies, both physical and spiritual. In the papyrus, it acknowledges the connection of the heart to the arteries. The Egyptians thought air came in through the mouth and into the lungs and heart. From the heart, the air traveled to every member through the arteries. Although this concept of the circulatory system is greatly flawed, it represents one of the earliest accounts of scientific thought.

The knowledge of circulation of vital fluids through the body was known to Sushruta (6th century BCE).^[1] He also seems to have possessed knowledge of the arteries, described as 'channels' by Dwivedi & Dwivedi (2007).^[1] The valves of the heart were discovered by a physician of the Hippocratean school around the 4th century BC. However their function was not properly understood then. Because blood pools in the veins after death, arteries look empty. Ancient anatomists assumed they were filled with air and that they were for transport of air.

Greek physician Herophilus distinguished veins from arteries but thought that the pulse was a property of arteries themselves. Greek anatomist Erasistratus observed that arteries that were cut during life bleed. He ascribed the fact to the phenomenon that air escaping from an artery is replaced with blood that entered by very small vessels between veins and arteries. Thus he apparently postulated capillaries but with reversed flow of blood.^[2]

The 2nd century AD, Greek physician, Galen, knew that blood vessels carried blood and identified venous (dark red) and arterial (brighter and thinner) blood, each with distinct and separate functions. Growth and energy were derived from venous blood created in the liver from chyle, while arterial blood gave vitality by containing pneuma (air) and originated in the heart. Blood flowed from both creating organs to all parts of the body where it was consumed and there was no return of blood to the heart or liver. The heart did not pump blood around, the heart's motion sucked blood in during diastole and the blood moved by the pulsation of the arteries themselves.

Galen believed that the arterial blood was created by venous blood passing from the left ventricle to the right by passing through 'pores' in the interventricular septum, air passed from the lungs via the pulmonary artery to the left side of the heart. As the arterial blood was created 'sooty' vapors were created and passed to the lungs also via the pulmonary artery to be exhaled.

In 1242, the Arabian physician, Ibn al-Nafis, became the first person to accurately describe the process of pulmonary circulation, for which he is sometimes considered the father of circulatory physiology.^[3] Ibn al-Nafis stated in his Commentary on Anatomy in Avicenna's Canon:

"...the blood from the right chamber of the heart must arrive at the left chamber but there is no direct pathway between them. The thick septum of the heart is not perforated and does not have visible pores as some people thought or invisible pores as Galen thought. The blood from the right chamber must flow through the vena arteriosa (pulmonary artery) to the lungs, spread through its substances, be mingled there with air, pass through the arteria venosa (pulmonary vein) to reach the left chamber of the heart and there form the vital spirit..."

Finally William Harvey, a pupil of Hieronymus Fabricius (who had earlier described the valves of the veins without recognizing their function), performed a sequence of experiments, and published Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus in 1628, which "demonstrated that there had to be a direct connection between the venous and arterial systems throughout the body, and not just the lungs. Most importantly, he argued that the beat of the heart produced a continuous circulation of blood through minute connections at the extremities of the body. This is is a conceptual leap that was quite different from Ibn al-Nafis' refinement of the anatomy and bloodflow in the heart and lungs."^[4] This work, with its essentially correct exposition, slowly convinced the medical world. However, Harvey was not able to identify the capillary system connecting arteries and veins; these were later described by Marcello Malpighi.

 Other images

 See also

• Microcirculation
• Cardiology
• Lymphatic system
• Blood vessels
• Innate heat
• Cardiac muscle
• Major systems of the human body
• Heart
• Amato Lusitano
• William Harvey

 References

1. ^ ^{a b} Dwivedi, Girish & Dwivedi, Shridhar (2007). History of Medicine: Sushruta – the Clinician – Teacher par Excellence. National Informatics Centre (Government of India).
2. ^ Anatomy - History of anatomy
3. ^ Chairman's Reflections (2004), "Traditional Medicine Among Gulf Arabs, Part II: Blood-letting", Heart Views 5 (2), p. 74-85 [80].
4. ^ Peter E. Pormann and E. Savage Smith, Medieval Islamic medicine Georgetown University, Washington DC, 2007, p. 48.

 External links

• The Circulatory System Article
• The Circulatory System, a comprehensive overview
• Berkeley Anatomy lecture on the vascular system
• NCP Cardiovascular Medicine A Journal Covering Clinical Cardiovascular Medicine