Infusion rate

If the drug is administered by a constant infusion rate (IR), the curve follows an unsteady function with zero-order kinetics (AClAt = const.) before the infusion is stopped (t < Tinfus) and first-order kinetics after cessation of infusion. Zero-order kinetics frequently can also be observed with diug absoiption where (KOabs = DR.) and (Tabs = Tinfus) hold true. 

When the physician orders a drug added to an intravenous (IV) fluid, the amount of fluid to be administered over a specified period, such as 125 mL/h or 1000 mL over 8 hours, must be included in the written order. If no infusion rate had been ordered, 1 L (1000 mL) of IV fluid should infuse over 6 to 8 hours. 

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. 

The nurse should administer each IV dose of vancomycin over 60 minutes Too rapid an infusion may result in a sudden and profound fall in blood pressure and shock. When giving the drug IV, the nurse closely monitors the infusion rate and the patient s blood pressure. The nurse reports any decrease in blood pressure or reports of throbbing neck or back pain. These symptoms could indicate a severe adverse reaction referred to as "red neck or "red man syndrome. 9/mptoms of this syndrome include a sudden and profound fall in blood pressure, fever, chills paresthesias and erythema (redness) of the neck and badk. 

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. 

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. 

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. 

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. 

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. 

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. 

Anaphylactic patients with impending shock, for example, those with incontinence, sudden loss of hearing or vision, dizziness, or collapse, and those with profound or persistent hypotension, require slow intravenous infusion of a dilute epinephrine solution [0.1 mg in 1 ml (1 10,000)]. Continuous hemodynamic monitoring and dose titration by trained and experienced healthcare professionals are essential. Maximum infusion rates of 5-15 ig/min are recommended in adults [2,18,22]. 

Nesiritide—2 mcg/kg IV bolus followed by a continuous IV infusion of 0.01 mcg/kg/min. Doses above the initial infusion rate should be limited to carefully selected patients. High-alert medication—read package insert before use... 

The optimal infusion rate is dependent on the volemic and hemodynamic status of the patient... 

When plasma glucose drops to 250 mg/dL, decrease insulin infusion rate and continue until acidosis is corrected (i.e., anion gap closes)... 

Do not exceed an infusion rate of 2 mg/min 0 Repeat every 5-15 min as needed up to three doses total... 

The infusion rate can be slowed if the seizure terminates or if an arrhythmia develops... 

Repeat as necessary until serum potassium normalizes ° Electrocardiogram monitoring is indicated when infusion rates exceed 10 mEq/h... 

Administer through a central line at <0.2 mEq/kg/h Decrease infusion rate in the presence of respiratory compensation to avoid respiratory acidosis ° Discontinue infusion when the arterial pH reaches 7.5... 

Treatment Loading Dose Continuous Infusion Rate Drug Interactions... 

Initial Loading Dose Initial Infusion Rate... 

Akathisia is disturbing for patients and can be disruptive to patient care. Giving diphenhydramine with prochlorperazine may reduce the incidence of akathisia, but the combination increases the risk of sedation.24 Slowing the intravenous infusion rate of prochlorperazine does not decrease akathisia.22,23... 

It is commonly used to treat severe hypernatremia. D5W is used in small volumes (100 mL) to dilute many IV medications or at a low infusion rate (10 to 15 mL/hour) to keep the vein open (KVO) for IV medications. 

Clinical Scenario Infusion Rate Concentration 24-hour Dose... 

Based on BA s opioid requirement, recommend an initial infusion rate (in milligrams per hour) of parenteral morphine. 

For breakthrough, give /4 to V2 of the scheduled dose as bolus every 1 -2 hours assess amount of rescue dose used in 8-12 hours and readjust scheduled dose or infusion rate as needed Other adjunct therapy ... 

Dextrose used in PN compounding typically is provided as a 70% stock solution (70 g/100 mL), although some institutions use a 50% stock solution. The final dextrose concentration in the PN solution typically should not exceed 35%. Hydrous dextrose provides 3.4 kcal/g (14.2 kj/g). A dextrose infusion rate of 2 mg/kg per minute should be sufficient to suppress gluconeogenesis and prevent protein breakdown in adults.5 Continuous dextrose infusion rate in adult patients generally should not exceed 4 to 5 mg/kg per minute in most hospitalized patients.6,7... 

PN can be administered via a smaller peripheral vein (e.g., cephalic or basilic vein) or via a larger central vein (e.g., superior vena cava). Peripheral PN (PPN) is infused via a peripheral vein and generally is reserved for short-term administration (up to 7 days) when central venous access is not available. PN formulations are hypertonic, and infusion via a peripheral vein can cause thrombophlebitis. Factors that increase the risk of phlebitis include high solution osmolarity, extreme pH, rapid infusion rate, vein properties, catheter material, and infusion time via the same vein.20 The osmolarity of PPN admixtures should be limited to 900 mOsm/L or less to minimize the risk of phlebitis. The approximate osmolarity of a PN admixture can be calculated from the osmolarities of individual components ... 

---