CATHETERS$

GUIDE WIRESBY

UBAH N.A

CONTENT: Guide wires Definitions Construction TypesCores Torque Tip Configurations Length Diameter Safety Test Precautions Seldinger Technique

Catheters •History $ Origin•Definition•Materials•Ideal Characteristics•Measurement•Classification•Main types•Other types•Uses•Sterilization •References

WHAT ARE GUIDE WIRES ?They are the stainless steel metallic structures that guides the catheter through the blood vessels for placement. Guide wires are used for both Cardiology and Radiology angiographic procedures.

Guide wires are relatively simple spring type wires that

provides necessary firmness and the control to the site where Angiogram will be taken.

As the name suggests it ‘ Guides’ the catheter.

PTFE coated Soft tip for the smoothness during the insertion

Less trauma to the intimal wall of the artery

Construction of Guide wires

They are Made of Stainless steel or other metallic Alloys.

Alloys are formed when two or more metals are mixed in a particular proportion to produce a single metallic substance.

Types Of Guide Wires They are two main types of Guide wires : The Solid Guide wire Wrapped Guide wire Both Types of Guide wire has one end that is rigid , with the opposite end flexible. The flexible tip is introduced into the blood vessel first, so that if the guide wire strikes a vessel wall, it will bend, thereby preventing damage to the vessel.

The advantages of solid Guide wires are that it reduces the Possibility of catheter tip flaring, Blood clotting on the guide wire, Abrasion of the vessel and the danger of unravelling. The one disadvantage of this type is its lack of versatility.

The Wrapped guide wire can be constructed so that it has a movable core, making it more versatile than the Solid Stainless Steel Guide wires, but it has other disadvantages:Possibility of catheter tip flaring. Blood clotting on the guide wire. Abrasion of the vessel. The danger of unravelling.

To reduce the disadvantages of wrapped Guide wire ( Damage to the catheter or the vessels ) , the wrapping maybe Teflon-coated or heparin-coated.

CoresThere are two main types of Guide wire Core :Fixed Cores ( for Normal Vascular System )

Movable Cores ( for Torturous vascular structures )The Movable core has a handle MANDRIL

TORQUE

Refers to the response of the guide wire or The Catheters to Movements ( like Twisting, bending and Turning )

Tip ConfigurationThere are two tip Configurations that are available for Guide Wires : The Straight tip

The J-shaped tip

Length:

Guide Wire Length varies from 30 to 260 cm. The shorter Guide wires (30 to 50 cm ) are usually used for percutanous or direct vascular puncture. The average Guide wire employed for adults undergoing selective Angiography is approx. 100 to 150 cm in length. The 260 cm guide wires are used when interchanging vascular catheters.

Diameter:The diameter of Guide wire s are measured in fractions of an inch, or millimeters. The range is 0.014” (0.35mm) to 0.052” (1.32mm). The most common diameters used for adults are 0.035” (0.089mm) and 0.038” (0.97mm).There are several factors to consider when selecting the proper diameter size. They are :

Needle gauge Vessel sizeSize of the lumen of the vascular catheter

Safety Test Three test are performed to determine the safety of the guide wire :Determination of the flexibility of the Guide wire tip by bending the tip 180 degrees.Visual inspection of wrapped guide wires junction of the stiff core and the external coils at the distal tip.Checking of the core by giving a slight twist and tug to the guide wire After the has passed these three safety tests, it is ready for use.

PrecautionsCertain Precautions must be taken when using a guide wire. These precautions include –

Care when advancing the guide wire.

Position of the needle beveled end .

Cleaning the guide wire.

Using a new guide wire.

Sven- Ivar Seldinger

In 1953 , Sven –Ivar Seldinger inventedThe technique of gaining access Percutaneusly into an artery without An arteriotomy.

TECHNIQUE OF INSERTING A CATHETER

SELDINGER TECHNIQUE :The technique of catheter insertion via double-wall needle puncture and guide-wire is known asThe SELDINGER TECHNIQUE.Double Wall Puncture:Mostly done. Compression to prevent Hematoma of the other wall. Rotatory movement to get the needle into the lumen.

Single Wall Puncture:Usually done for patients coagulation time is less.

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PUNCTURE NEEDLES:Used to cannulate or puncture the artery.

Usual Sizes include 18 g, 19 g , 20g, 21 g.

The selection of the Size depends on the guide wire going to be inserted through that needle port.

Seldinger Needle

CATHETERS

Late Latin, from Greek:KATHETER, came from KATHIENAI, kathe- to send down : kat-, kata-, cata- + hienai- to send .

HISTORY AND ORIGIN OF “CATHETER”

In 1929 Werner Forssmann demonstrated that a simple Rubber catheter could be passed to the pulmonary artery through the Anti-Cubital Vein and An angiographic film could be obtained using radiographic contrast.

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DEFINITION :A catheter is a hollow flexible tube that can be inserted into a body cavity, duct or vessel. Catheters thereby allow drainage or injection of fluids , distend a passageway or provide access by surgical instruments.The process of inserting a catheter is catheterization.

WHAT ARE CATHETERS MADE UP OF ?Materials:

A range of polymers are used for the construction of catheters, including silicone rubber latex and thermoplastic elastomers. Silicone is one of the most common choices because it is inert and unreactive to body fluids and a range of medical fluids with which it might come into contact.

Materials:Polyethylene (PE)Fluoropolomers (PTFE) (TEFLON)Polyurethane (PUR)Silicone (SI)Polyvinylchloride (PVC)

Ideal characteristics of catheters. Better Torque Control

Strength

Radiopacity

Flexible

Atraumatic Tip

Low Surface frictional resistance for good track ability over guide wire.

Joseph Charrière (March 19, 1803 – April 28, 1876) was a Swiss-born French manufacturer of surgical instruments.

Joseph-Frédéric-Benoît Charrière

He Invented the French Gauge or the French Scale for measuring the Diameter of A Catheter .

MEASUREMENT:

FRENCH CATHETER SCALE:

The French catheter scale (most correctly abbreviated as Fr, but also often abbreviated as FR or F) is commonly used to measure the outer diameter of cylindrical medical instruments including catheters , needles etc.

In the French Gauge system as it is also known, the diameter in millimeters of the catheter can be determined by dividing the French size by 3, thus an increasing French size corresponds with a larger diameter catheter. The following equations summarize the relationships:

D(mm) = Fr/3 or Fr = D(mm)*3

The French scale or French gauge system is commonly used to measure the size of a catheter. It is most often abbreviated as Fr, but can often be seen abbreviated as Fg, Ga, FR or F. It may also be abbreviated as CH or Ch (for Charrière, its inventor).

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A catheter of 1 French has an external diameter of 1⁄3 mm,[1] and therefore the diameter of a round catheter in millimeters can be determined by dividing the French size by 3:D (mm) = Fr / 3orFr = D (mm) * 3For example, if the French size is 9, the diameter is 3 mm.

Most commonly in adult Diagnostic Catheters of 5 – 7 Fr are used.

Diagnostic Angiographic Catheters.

Micro catheters.

Drainage Catheters.

Balloon Catheters.

Central Venous Catheters.

CATHETERS CAN BE BROADLY CLASSIFIED

UNDER THESE GROUPS:

Cerebral Catheters:Hinck-Hilal ( head Hunter ) Catheter- Used for $ vessel Cerebral Angiogram. For more tortuous and Elongated Arch we use :Bentson Hanafee Wilson (JB2, JB3)Simmons (SIM2)Simmons catheter can also be used for selective Visceral angiography

Diagnostic Angiographic Catheters

Visceral Catheters

Shepherd’s hook / Hockey stick Catheter.Cobra Head Catheter.

Coronary Catheters

Judkins Catheters.Amplatz Catheters.Sones Coronary catheters.

Judkins Left Judkins Right

Amplatz Left Amplatz Right

Coronary Catheters

Renal CathetersSelective catheters-Simmons or sidewinder Catheters.RDC (Renal double curved selective catheters)

Semi selective Catheters has 6 side holes just proximal to the tapered part.

Mircocatherters 3 F or Smaller.Designed for distal Catheterization.Placed over o.010 to 0.018 guide wire.Used mostly for Neuro-interventionHelpful in peripheral intervention to select smaller vessels for embolization.

Drainage Catheters

Used for drainage of fluid collection including nephrostomy, abscess, biliary gall bladder, pleural fluid, ascites, lymphoceles.

Balloon (Angioplasty) Catheters Either very soft and pliable as occlusion balloon or forgarty balloon to clear thrombosis or can be rigid and used for dilatation ( ANGIOPLASTY ).Balloon for dilatation can be divided into 2 main categories regarding the size of guide wire over which they are placed.

Porst Mann’s Korsetts balloon CatheterDotter coaxial catheterCaged balloon catheterPVC balloon catheter

Balloon (Angioplasty) Catheters

Central Venous Catheters There are Three Basic categories of catheters :Non-Tunnelled catheters – these catheters are placed via central veins ( subclavian and internal jugular) by blinded percutaneus technique.

Tunnelled Catheters – They can be accessed externally and are designed for long term home use.

Implanted subcutaneus port – these are attached to the port that is buried subcutaneously for stabilization. They maybe placed either on chest wall or the upper arm.

Catheters can be classified depending on SIDE HOLES : -: Single Hole -:End Hole with side holes. -:Blocked end with side holes only.

Other Classifications:

SIZES :Abdominal – 6-80 cm Thoracic or Carotid Arteries – 100-120 cm NOTE: Size depends on : > age of the patient > selective or super selective study > size of the vessels.NOTE: Ideal practice is to use the smallest diameter catheter feasible for any particular study to minimize the risk of arterial damage by the procedure.

SHAPES Straight Catheter

Pigtailed Catheter ( For Ventricles and Arch of Aorta )

Cobra Shaped Catheter

Side Winder Catheters (Shepherd) These four Catheters are commonly used in the Radiology department .

Straight Catheter

Pigtailed Catheter ( For Ventricles and Arch of Aorta )

Side Winder Catheters (Shepherd)

Both Pigtailed And Straight Catheters are used for injecting a large volume of contrast at a high rate ( velocity ) . Thus, they have multiple side holes . They are also called FLUSH CATHERTERS

Some Other Types of Catheters: Hydrophilic Catheters :Hydrophilic-coated catheters have a layer of polymer coating that is bound to the catheter surface. The polymer absorbs and binds water to the catheter, resulting in a thick, smooth and slippery surface.

Intermittent Catheters:Intermittent catheters are hollow tubes used to drain urine from the bladder.

Pediatric Catheters:Usually its around 80cm.

Balloon Catheters:

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Butterfly Catheters Foleys Catheter (1way, 2way or 3way)

COMPLETE APPARATUS:

Needle

Guide Wire

Sheath

Catheter

USES & APPLICATIONS OF CATHETERS:

Placement of a catheter into a particular part of the body may allow:

Draining urine from the urinary bladder as in urinary catheterization, e.g., the Foley catheter.

Drainage of urine from the kidney pelvis by percutaneous nephrostomy.

Drainage of fluid collections, e.g. an abdominal abscess.

Administration of intravenous fluids, medication or parenteral nutrition with a peripheral venous catheter.

Angioplasty , angiography , balloon septostomy, balloon angioplasty. Often Seldinger technique is used.A central venous catheter is a conduit for giving drugs or fluids into a large-bore catheter positioned either in a vein near the heart or just inside the atrium.

A Swan - Ganz catheter is a special type of catheter placed into the pulmonary artery for measuring pressures in the heart.

CONTD…

Direct measurement of blood pressure in an artery or vein.

Direct measurement of intracranial pressure.

Administration of anesthetic medication into the epidural space, the subarachnoid space, or around a major nerve bundle such as the brachial plexus.

Subcutaneous administration of insulin or other medications.

CONTD…

Before giving for sterilization, catheter should be washed in water and with air jets so that clots in the catheter lumen come out.

Methods for cleaning, decontaminating, and sterilizing catheters are by using a combination of liquid and gaseous/plasma sterilization techniques to ensure the complete and efficient sterilization of a catheter .

Methods and apparatus for cleaning, decontaminating, and sterilizing catheters

Angiographic dye and saline are removed from the interior of the balloon and its lumen . The outer surfaces of the catheter and a guide wire lumen of the catheter are cleaned, decontaminated, and sterilized with a liquid sterilant.

The liquid sterilant fills a balloon and a balloon lumen of the catheter .

The filling, retaining, and draining steps are repeated until an interior of the balloon and the balloon lumen are sterilized.

STERLIZATION OF CATHETERS:Methods for catheter sterilization :

The catheter is dried and then a plasma or gaseous sterilant is used to sterilize at least the outer surfaces and the guide wire lumen of the catheter.

Techniques for effectively sterilizing catheters, particularly long-dwelling intravenous catheters includes

>> the transmission and dispersion of ultraviolet or infrared radiation

Websites:Wikipedia

Google

Books: Radiological Procedures –A Guideline Cardiac Catheterization.

REFERENCES: