Rabu, 09 April 2008

"Intravenous Therapy"

"Intravenous Therapy"

Intravenous therapy or IV therapy is the administration of liquid substances directly into a vein. It can be intermittent or continuous; continuous administration is called an intravenous drip. The word intravenous simply means "within a vein", but is most commonly used to refer to IV therapy.

A. Indications :
1. Establish or maintain a fluid or electrolyte balance
2. Administer continuous or intermittent medication
3. Administer bolus medication
4. Administer fluid to keep vein open (KVO)
5. Administer blood or blood components
6. Administer intravenous anesthetics
7. Maintain or correct a patient's nutritional state
8. Administer diagnostic reagents
9. Monitor hemodynamic functions

B. IV Devices :
a. Steel Needles :
Example: Butterfly catheter. They are named after the wing-like plastic tabs at the base of the needle. They are used to deliver small quantities of medicines, to deliver fluids via the scalp veins in infants, and sometimes to draw blood samples (although not routinely, since the small diameter may damage blood cells). These are small gauge needles

b. Over the Needle Catheters
Example: peripheral IV catheter. This is the kind of catheter you will primarily be using. Also see the close up view of the catheter/needle tip in the next section ("inside the needle catheters").

Catheters (and needles) are sized by their diameter, which is called the gauge. The smaller the diameter, the larger the gauge. Therefore, a 22-gauge catheter is smaller than a 14-gauge catheter. Obviously, the greater the diameter, the more fluid can be delivered. To deliver large amounts of fluid, you should select a large vein and use a 14 or 16-gauge catheter. To administer medications, an 18 or 20-gauge catheter in a smaller vein will do.

C. IV Fluids :
Intravenous fluids are usually provided to:
- Provide volume replacement
- Administer medications, including electrolytes
- Monitor cardiac functions

For example, a patient comes into the ED with gastroenteritis and is dehydrated from vomiting and diarrhea. Acutely, she receives a fluid bolus to expand her intravascular volume. Her blood chemistry shows that her electrolytes are a bit off, so the IV fluid is adjusted to bring them within normal parameters. She is also given medication for nausea via her IV. She will remain on maintenance IV fluids until she is able to drink adequate amounts of fluids.

There are three main types of fluids:
- Isotonic fluids:
Can be helpful in hypotensive or hypovolemic patients.
Can be harmful. There is a risk of fluid overloading, especially in patients with CHF and hypertension.
Examples: Lactated Ringer's (LR), NS (normal saline, or 0.9% saline in water

- Hypotonic fluids:
Can be helpful when cells are dehydrated such as a dialysis patient on diuretic therapy. May also be used for hyperglycemic conditions like diabetic ketoacidosis, in which high serum glucose levels draw fluid out of the cells and into the vascular and interstitial compartments.
Can be dangerous to use because of the sudden fluid shift from the intravascular space to the cells. This can cause cardiovascular collapse and increased intracranial pressure (ICP) in some patients.
Example: .45% NaCl, 2.5% dextrose

- Hypertonic fluids :
Can help stabilize blood pressure, increase urine output, and reduce edema.
Rarely used in the prehospital setting. Care must be taken with their use. Dangerous in the setting of cell dehydration.
Examples: D5% .45% NaCl, D5% LR, D5% NS, blood products, and albumin.

Flow Rates :
You will often need to calculate IV flow rates. The administration sets come in two basic sizes:
1.Microdrip sets, Allow 60 drops (gtts) / mL through a small needle into the drip
chamber (Good for medication administration or pediatric fluid delivery).
2.Macrodrip sets, Allow 10 to 15 drops / mL into the drip chamber (Great for rapid
fluid delivery. Also used for routine fluid delivery).
3.Fluid may be ordered at a KVO rate. This means to Keep the Vein Open, or run in
fluids very slowly, enough to keep the vein open, but not really deliver much
volume.At times, you may desire a faster flow rate. This is usually expressed in
mLs / hour. In other words, how much fluid do you want your patient to receive
each hour? A common "maintenance" amount, for instance, would be "run it in at 125
an hour". Your patient would receive 125 mL of fluid every hour.

This is usually done by counting the number of drops that fall into the clear drip chamber on the IV administration set in one minute. To do this, you must know what size administration set you are using (micro or macrodrip). Plug the numbers into the following formula and you've got it!
(volume in mL) x (drip set) gtts
------------------------------------ = ------
(time in minutes) min

D. Vein Selection:
Veins of the Hand
1. Digital Dorsal veins
2. Dorsal Metacarpal veins
3. Dorsal venous network
4. Cephalic vein
5. Basilic vein

Veins of the Forearm
1. Cephalic vein
2. Median Cubital vein
3. Accessory Cephalic vein
4. Basilic vein
5. Cephalic vein
6. Median antebrachial vein

E. Technique:
Remember the four rights:Do I have the right patient?Do I have the right solution?Do I have the right drug?Do I have the right route?.

It is important to gather all the necessary supplies before you begin. You will need: Absorbent disposable sheet, 1 alcohol prep pad, 1 betadine swab, Tourniquet, IV catheter, IV tubing, Bag of IV fluid. 4 pieces of tape (preferably paper tape or easy to remove tape which has been precut to approximately 4 inches (10cm) in length and taped conveniently to the table or stretcher. Disposable gloves, Gauze (several pieces of 4x4 or 2x2)

Prepare the IV fluid administration set.Inspect the fluid bag to be certain it contains the desired fluid, the fluid is clear, the bag is not leaking, and the bag is not expired.
Select either a mini or macro drip administration set and uncoil the tubing. Do not let the ends of the tubing become contaminated.Close the flow regulator (roll the wheel away from the end you will attach to the fluid bag).Remove the protective covering from the port of the fluid bag and the protective covering from the spike of the administration set.Insert the spike of the administration set into the port of the fluid bag with a quick twist. Do this carefully. Be especially careful to not puncture yourself!

Hold the fluid bag higher than the drip chamber of the administration set. Squeeze the drip chamber once or twice to start the flow. Fill the drip chamber to the marker line (approximately one-third full). If you overfill the chamber, lower the bag below the level of the drip chamber and squeeze some fluid back into the fluid bag. Open the flow regulator and allow the fluid to flush all the air from the tubing. Let it run into a trash can or even the (now empty) wrapper the fluid bag came in. You may need to loosen or remove the cap at the end of the tubing to get the fluid to flow although most sets now allow flow without removal. Take care not to let the tip of the administration set become contaminated.

Turn off the flow and place the sterile cap back on the end of the administration set (if you've had to remove it). Place this end nearby so you can reach it when you are ready to connect it to the IV catheter in the patient's vein.
Perform the venipuncture
Be sure you have introduced yourself to your patient and explained the procedure. Apply a tourniquet high on the upper arm. It should be tight enough to visibly indent the skin, but not cause the patient discomfort. Have the patient make a fist several times in order to maximize venous engorgement. Lower the arm to increase vein engorgement.
Select the appropriate vein. If you cannot easily see a suitable vein, you can sometimes feel them by palpating the arm using your fingers (not your thumb) The vein will feel like an elastic tube that "gives" under pressure. Tapping on the veins, by gently "slapping" them with the pads of two or three fingers may help dilate them. If you still cannot find any veins, then it might be helpful to cover the arm in a warm, moist compress to help with peripheral vasodilatation. If after a meticulous search no veins are found, then release the tourniquet from above the elbow and place it around the forearm and search in the distal forearm, wrist and hand. If still no suitable veins are found, then you will have to move to the other arm. Be careful to stay away from arteries, which are pulsatile.

Don disposable gloves. Clean the entry site carefully with the alcohol prep pad. Allow it to dry. Then use a betadine swab. Allow it to dry. Use both in a circular motion starting with the entry site and extending outward about 2 inches. (Using alcohol after betadine will negate the effect of the betadine) Note that some facilities may require an alcohol prep without betadine or sometimes alcohol after betadine. Go with the rules for your facility.

To puncture the vein, hold the catheter in your dominant hand. With the bevel up, enter the skin at about a 30 degree angle and in the direction of the vein. Use a quick, short, jabbing motion. After entering the skin, reduce the angle of the catheter until it is nearly parallel to the skin. If the vein appears to "roll" (move around freely under the skin), begin your venipuncture by apply counter tension against the skin just below the entry site using your nondominant hand. Many people use their thumb for this. Pull the skin distally toward the wrist in the opposite direction the needle will be advancing. Be carefully not to press too hard which will compress blood flow in the vein and cause the vein to collapse. Then pierce the skin and enter the vein as above.
Advance the catheter to enter the vein until blood is seen in the "flash chamber" of the catheter.

If not successful
If you are unsuccessful in entering the vein and there is no flashback, then slowly withdraw the catheter, without pulling all the way out, and carefully watch for the flashback to occur. If you are still not within the vein, then advance it again in a 2nd attempt to enter the vein. While withdrawing always stop before pulling all the way out to avoid repeating the painful initial skin puncture. If after several manipulations the vein is not entered, then release the tourniquet, place a gauze over the skin puncture site, withdraw the catheter and tape down the gauze. Try again in the other arm.
Otherwise,After entering the vein, advance the plastic catheter (which is over the needle) on into the vein while leaving the needle stationary. The hub of the catheter should be all the way to the skin puncture site. The plastic catheter should slide forward easily. Do not force it!!

(release the tourniquet)
Apply gentle pressure over the vein just proximal to the entry site to prevent blood flow. Remove the needle from within the plastic catheter. Dispose of the needle in an appropriate sharps container. NEVER reinsert the needle into the plastic catheter while it is in the patient's arm! Reinserting the needle can shear off the tip of the plastic catheter causing an embolus. Remove the protective cap from the end of the administration set and connect it to the plastic catheter. Adjust the flow rate as desired.

Tape the catheter in place using the strips of tape and a sterile 2X2 or a clear dressing. It is advisable not to use the "chevron" taping technique.
Label the IV site with the date, time, and your initials.Monitor the infusion for proper flow into the vein (in other words, watch for infiltration).

Occasionally, you may inadvertently enter an artery. You'll recognize this because bright red blood is quickly seen in the IV tubing and the IV bag because of the high pressure that exists. If this occurs, stop the fluid flow, remove the catheter, and put pressure on the site for at least 5 minutes.

To discontinue an IV
Remember to observe universal precautions. Start by clamping off the flow of fluids. Then gently peel the tape back toward the IV site. As you get closer to the site and the catheter, stabilize the catheter and remove the rest of the tape from the patient's skin. Then place a 4 x 4 gauze over the site and gently slide the plastic catheter out of the patient's arm. Use direct pressure for a few minutes to control any bleeding. Finally, place a band aide over the site.

Complications: Bruising, Cellulitis, Infiltrate, Extravasation, Phlebitis, Systemic Complications.

# Refences :
Steve Martin, PhD(c), PA-C
Nova Southeastern University PA Program

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