IV infusion

Time to peak plasma concentration depends on the rate of IV dosing but is usually achieved in 45—90 seconds. Therapeutic plasma concentrations are 1.5—5.0 )J.g/mL, and concentrations above 5 )J.g/mL maybe toxic. The elimination half-life after a bolus iv dose is 8 min the elimination half-life after a 24 h iv infusion is about 100 min. The dmg is eliminated by the kidneys. Ten percent is unchanged and the remainder is in the form of inactive metabolites... 

Elestolol sulfate is a nonselective, ultrashort acting P-adrenoceptor blocker. It has no ISA and produces weak inhibition of the fast sodium channel. The dmg is under clinical investigation for supraventricular tachyarrhythmias, unstable angina, and acute MI. In humans, flestolol has hemodynamics and electrophysiologic effects similar to those of other P-adrenoceptor blockers. The pharmacokinetics of flestolol are similar to those of esmolol. It is 50 times more potent than esmolol and the elimination half-life is 7.2 min. Recovery from P-adrenoceptor blockade is 30—45 min after stopping iv infusions. The dmg is hydrolyzed by tissue esterases and no active metabohtes of flestolol have been identified (41). 

After po dosing, verapamil s absorption is rapid and almost complete (>90%). There is extensive first-pass hepatic metabolism and only 10—35% of the po dose is bioavahable. About 90% of the dmg is bound to plasma proteins. Peak plasma concentrations are achieved in 1—2 h, although effects on AV nodal conduction may be apparent in 30 min (1—2 min after iv adrninistration). Therapeutic plasma concentrations are 0.125—0.400 p.g/mL. Verapamil is metabolized in the liver and 12 metabolites have been identified. The principal metabolite, norverapamil, has about 20% of the antiarrhythmic activity of verapamil (3). The plasma half-life after iv infusion is 2—5 h whereas after repeated po doses it is 4.5—12 h. In patients with liver disease the elimination half-life may be increased to 13 h. Approximately 50% of a po dose is excreted as metabolites in the urine in 24 h and 70% within five days. About 16% is excreted in the feces and about 3—4% is excreted as unchanged dmg (1,2). 

Use of an infuson pump or controller still requires nursing supervision and frequent monitoring of the IV infusion. Infiltration can progress rapidly because the increased pressure will not s/ow the infuson until considerable edema has occurred. Therefore, it is important to monitor frequently for signs of infiltration, such as edema or redness at the site. Careful monitoring of the pump or controller is also necessary to make sure the flow rate is correct. 

To allow the IV fluid to infuse over a specified period, the IV flow rate must be determined. Before using one of the methods below, the drop factor must be known. Drip chambers on the various types of IV fluid administration sets vary. Some deliver 15 drops/mL and others deliver more or less than this number. This is called the drop factor. The drop factor (number of drops/mL) is given on the package containing the drip chamber and IV tubing. Three methods for determining the IV infusion rate follow. Methods 1 and 2 can be used when the known factors are the total amount of solution, the drop factor, and the number of hours over which the solution is to be infused. 

MONITORING DRUGS GIVEN INTRAVENOUSLY. For optimal results, die nurse inspects the needle site and die area around die needle every hour for signs of extravasation of die IV fluid. The nurse performs diese assessments more frequently if the patient is restiess or uncooperative It is important to check the rate of infusion every 15 minutes and adjust it as needed. The nurse should inspect die vein used for die IV infusion every 4 hours for signs of tenderness, pain, and redness (which may indicate phlebitis or thrombophlebitis). If tiiese are apparent, die nurse must restart the IV in another vein and bring the problem to the attention of the primary health care provider. 

Vancomycin. The nurse can administer vancomycin orally or by intermittent IV infusion. This drug is not administered IM. Unused portions of reconstituted oral suspensions and parenteral solutions are stable for 14 days when refrigerated after reconstitution. 

AM PHOTERICIN B The nurse administers tins drag daily or every otiier day over several months. The patient is often acutely ill witii a life-tiireatening deep fungal infection. The nurse should reconstitute the drag according to tiie manufacturer s instructions. Sterile water is used for reconstitution because any otiier diluent may cause precipitation. Immediately after the drag is reconstituted, die nurse administers the IV infusion over a period of 6 hours or more... 

The nurse checks the IV infusion rate and the infusion site frequently during administration of the drug. This is especially important if the patient is restless or confused. 

If naloxone is given by IV infusion, die primary healdi care provider orders die IV fluid and amount, the drug dosage and die infusion rata Giving the drag by IV infusion requires use of a secondary line or IV piggyback. 

The nurse can give some of these drug (for example, aminophylline or theophylline) IV, either direct IV or as an IV infusion. When giving theophylline or aminophylline IV, the nurse monitors die patient for hypotension, cardiac arrhythmias, and tachycardia. If a bronchodilator is given IV, the nurse administers it through an infusion pump. The nurse checks die IV infusion site at frequent intervals because these patients may be extremely restless, and extravasation can occur. 

Heparin may be given by intermittent IV administration, continuous IV infusion, and the SC route. Intramuscular administration is avoided because of die possibility of the development of local irritation, pain, or hematoma (a collection of blood in die tissue). A solution of dilute heparin may be used to maintain patency of an IV site used for intermittent administration of any drug given by die IV route ... 

An infusion pump must be used for the safe administration of heparin by continuous IV infusion. The nurse checks die infusion pump every 1 to 2 hours to ensure diat it is working properly. The needle site is inspected for signs of inflammation, pain, and tenderness along... 

Blood coagulation tests for those receiving heparin by continuous IV infusion are taken at periodic intervals (usually every 4 hours) determined by the primary health care provider. If the patient is receiving long-term heparin therapy, blood coagulation tests may be performed at less frequent intervals... 

HISTAMINE H2 ANTAGONISTS. The nurse administers ranitidine and oral cimetidine before or with meals and at bedtime Nizatidine and famotidine are given at bedtime or, if twice-a-day dosing is prescribed, in the morning and at bedtime. These drugp are usually given concurrently with an antacid to relieve the pain. In certain situations or disorders, cimetidine and ranitidine may also be given by intermittent IV infusion or direct IV injection. 

Before starting an IV infusion of oxytocin for the induction of labor, the nurse obtains an obstetric history (parity, gravidity, previous obstetric problems, type of labor, stillbirths, abortions, live birth infant abnormalities)... 

OXYTOCIN The patient receiving oxytocin to induce labor may have concern over the use of the drug to produce contractions. When given to induce or stimulate contractions, oxytocin may only be given intravenously (IV). The nurse explains the purpose of the IV infusion and the expected results to the patient. Because the patient receiving oxytocin must be closely supervised, the nurse spends time with the patient and offers encouragement and reassurance to help reduce anxiety. 

When oxytocin is prescribed, the primary health care provider orders the type and amount of IV fluid, the number of units of oxytocin added to the IV solution, and the IV infusion rate An electronic infusion device is used to control the infusion rate. The primary health care provider establishes guidelines for the administration of the oxytocin solution and for increasing or decreasing the flow rate or discontinuing the administration of oxytocin based on standards established by the Association of Women s Health, Obstetric, and Neonatal Nurses (AWHONN). Usually, the flow rate is increased every 20 to 30 minutes, but this may vary according to the patient s response. The strength, frequency, and duration of contractions and the FHR are monitored closely. 

Before starting an IV infusion containing ritodrine or terbutaline, the nurse obtains the patient s vital signs. The nurse auscultates lung sounds to provide a baseline assessment. The nurse places the patient on a monitoring device to determine uterine contractions and the FHR before and during administration. 

The primary healtii care provider is kept informed of die patient s response to die drug because a dosage change may be necessary. The primary healdi care provider establishes guidelines for die regulation of die IV infusion rate, as well as die blood pressure and pulse ranges tiiat require stopping die IV infusion. 

Most antineoplastic dragp have specific recommended administration techniques. For example, an infusion pump is recommended for the administration of cisplatin, and plicamycin (Mithracin) is administered by slow IV infusion during a period of 4 to 6 hours. If administration guidelines are not provided by the primary health care provider or the hospital, the nurse checks with the appropriate authorities (physician, pharmacist) regarding the administration of a specific antineoplastic drug. 

During the ongoing assessment, the nurse checks the needle site every 15 to 30 minutes or more frequently if the patient is restless or confused. When one of these preparations is given with a regular IV infusion set, the nurse checks the infusion rate every 15 minutes. The needle site is inspected for signs of extravasation (escape of fluid from a blood vessel into surrounding tissues) orinfiltration (the collection of fluid into tissues). 

The nurse observes patients receiving IV solutions at frequent intervals for signs of fluid overload. If signs of fluid overload (see Display 58-1) are observed, the nurse slows the IV infusion rate and immediately notifies the primary health care provider. 

Promoting an Optimal Response to Therapy Fhtients receiving an IV fluid should be made as comfortable as possible, although under some circumstances this may be difficult. The extremity used for administration should be made comfortable and supported as needed by a small pillow or other device An IV infusion pump may be ordered for the administration of these solutions. The nurse sets the alarm of the infusion pump and checks the functioning of the unit at frequent intervals. 

The nurse inspects the IV needle site every 30 minutes for signs of extravasation. Potassium is irritating to the tissues. If extravasation occurs, the nurse discontinues the IV immediately and notifies the primary health care provider. The acutely ill patient and the patient with severe hypokalemia will require monitoring of the blood pressure and pulse rate every 15 to 30 minutes during the time of the IV infusion. The nurse measures the intake and output every 8 hours. The infusion rate is slowed to keep the vein open, and the primary health care provider is notified if an irregular pulse is noted. 

SODIUM When NaCl is administered by IV infusion, the nurse observes the patient during and after administration for signs of hypernatremia (see Display 58-2). The nurse checks the rate of IV infusion as ordered by the primary health care provider, usually every 15 to 30 minutes. More frequent monitoring of the infusion rate may be necessary when the patient is restless or confused. To minimize venous irritation during administration of sodium or any electrolyte solution, the nurse uses a small bore needle placed well within the lumen of a large vein. 

Fhtients receiving a 3% or 5% NaCl solution by IV infusion are observed closely for signs of pulmonary edema (dyspnea, cough, restlessness, bradycardia). If any one or more of these symptoms should occur, the IV infusion is slowed to keep the vein open, and the primary health care provider is contacted immediately. Fhtients receiving NaCl by the IV route have their intake and output measured every 8 hours. The nurse observes the patient for signs of hypernatremia every 3 to 4 hours and contacts the primary health care provider if this condition is suspected. 

The primary health care provider orders the dose of tiie potassium salt (in mEq) and the amount and type of IV solution, as well as the time interval during which tiie solution is to be infused. After the drug is added to tiie IV container, tiie container is gently rotated to ensure mixture of tiie solution. A large vein is used for administration tiie veins on tiie back of tiie hand should be avoided. An IV containing potassium should infuse in no less than 3 to 4 hours. This necessitates frequent monitoring of the IV infusion rate, even when an IV infusion pump is used. 

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