Question

Calculate the units as indicated by the problem. Use labels where provided to calculate dosages. Order: \(1 \mathrm{~L}\) of \(0.9 \% \mathrm{NS}\) with 40,000 units heparin over \(24 \mathrm{hr}\). Calculate the following: a. \(\mathrm{mL} / \mathrm{hr}\) b. units/hr

Short answer

a. 41.67 mL/hr b. 1666.67 units/hr

Step-by-step solution

Understand the Order

The order requires administering 1 liter (1000 mL) of a 0.9% normal saline (NS) solution with 40,000 units of heparin over 24 hours. We need to find the infusion rate both in terms of mL per hour and units of heparin per hour.

Calculate mL per Hour

To find the infusion rate in mL per hour, divide the total volume of the solution by the total time of infusion: \[\text{mL/hr} = \frac{1000\, \text{mL}}{24\, \text{hr}}\]Simplifying gives:\[\text{mL/hr} = 41.67\, \text{mL/hr}\]

Calculate Units per Hour

To find the infusion rate in units of heparin per hour, divide the total units of heparin by the total infusion time:\[\text{units/hr} = \frac{40,000\, \text{units}}{24\, \text{hr}}\]Simplifying gives:\[\text{units/hr} = 1666.67\, \text{units/hr}\]

Key concepts

Heparin Dosage

Let's start by understanding what heparin dosage means. Heparin is an anticoagulant, which means it helps prevent blood clots from forming in the blood vessels. Healthcare providers prescribe specific doses to ensure its safe and effective use. In medical settings, particularly in hospitals, heparin is commonly given intravenously (through a vein) or by subcutaneous (under the skin) injection.
This medication is often added to larger volumes of solutions like normal saline to administer a controlled amount over time. The dosage varies depending on the condition being treated. For example, for patients at risk of clots, continuous intravenous infusions using dosages like 40,000 units in a controlled setting are typical. The heparin dosage in the original problem specifies 40,000 units to be infused over 24 hours.

Infusion Rate

Infusion rate is the speed at which a solution is administered intravenously. To calculate the infusion rate, we need both the total volume of the solution and the total time over which it is to be administered. In the scenario given, the solution is a mix of 1 liter (1000 mL) of 0.9% normal saline with 40,000 units of heparin, meant to be dispensed over 24 hours.
To determine how many milliliters per hour (mL/hr) the mixture should be infused, use the formula:

• Divide the total volume (1000 mL) by the total number of hours (24 hours).

This gives us the infusion rate of approximately 41.67 mL/hr. The calculated rate needs to match the patient's needs, ensuring continuous, appropriate medication delivery.

Normal Saline Solution

Normal saline solution (NS) is a sterile solution of sodium chloride (salt) in water. It is one of the most common intravenously administered fluids in medical practice. The 0.9% concentration indicates that the solution has the same salt concentration as blood, making it 'isotonic'.
This characteristic ensures that administering it does not disrupt the balance of fluids in the body. Normal saline is used for hydration, as a vehicle for delivering medications like heparin, or for flushing equipment during medical procedures. In the problem exercise, normal saline acts as the fluid medium to safely administer the 40,000 units of heparin over a 24-hour period.

Units per Hour

Units per hour is a measurement of how much medication (in this case, heparin) is delivered over time. It's crucial for medications that need to be administered continuously or in precise quantities for effective therapeutic results. Higher or lower rates might lead to therapeutic failure or adverse effects.
In practical application, calculating units per hour helps medical professionals ensure the right amount of medication is delivered to patients, avoiding both under-medication and overdosing. With the problem's parameters, you simply divide the total units (40,000 units) by the number of hours (24 hours) to find that the infusion should be approximately 1666.67 units/hour. This calculation is essential in patient management, especially for those at risk of clotting disorders that require precise anticoagulation therapy.