The IV League

Q: “What is the difference between IV bolus, IV infusion, IV injection, IV push and IV drip?”

Let’s look at what each of these terms mean:

• Intravenous injection: a hypodermic injection into a vein for the purpose of instilling a single dose of medication, injecting a contrast medium, or beginning an IV infusion of blood, medication, or a fluid solution, such as saline or dextrose in water.

• IV bolus: concentrated medication and/or solution given rapidly over a short period of time

Eg.  Fluid bolus: a rapid administration of fluids to correct hypotensive shock. It typically includes the infusion of at least 500 ml over a maximum of 15 min.

• IV push: manual administration of medication under pressure, can be over several minutes; does not necessarily mean  in seconds. Most medications are given over more than a minute.

( IV push = IV bolus; the time over which a medication is given and its dilution, if any, varies)

IV infusions:
Continuous infusion – a large volume of infusion fluid (with or without the addition of a medicine), Eg:  Fluid infusion: continuous delivery of i.v. fluids to maintain homeostasis, replace losses, or prevent organ injury (e.g. prehydration before operation or for contrast nephropathy)

Intermittent infusion –a small volume infusion administered at a prescribed rate, usually at specific time intervals during the day. Generally, it is a secondary medication that is given over a few hours, one or more times a day.

IV drip : the continuous infusion of fluids, with or without medications, through an IV route.

Can be through an infusion pump shown in Image C ( a machine used to control the flow rate and total amount of medication and/or fluids delivered by IV). Especially useful for noradrenaline/dopamine since the they are infused in minute quantities.

The drip rate is calculated per hour/per min and entered into the infusion pump monitor or the drop rate is calculated as drops/min.

(IV infusion = IV drip, can be used interchangeably)

The image A below shows a continuous fluid infusion bag on the left and an intermittent infusion bag on the right. They can be given simultaneously using a three way cannula or can be given one at a time by closing the respective port.

The drip rate can be controlled as shown in image B.

Image A

Image B

                                    

Image C - Infusion pump: The pink fluid is the medication, the screen above shows the current rate of infusion/drip rate.

To understand how these terms are used, look at these two examples:

1. In a patient with Type 1 DM presenting with DKA:

Initial IV bolus of 0.9% normal saline of 2-3 litres over 1-3 hours, followed by continuous infusion of 0.9%/0.45% normal saline depending on calculated volume deficit.

Also, an IV bolus of short acting insulin at 0.1U/kg followed by continuous infusion at rate of 0.1U/kg per hour.

In case the serum potassium level is less than 5meq/L, an intermittent infusion of potassium chloride/phosphate can be administered until the levels normalise. (This is to be done before giving insulin to prevent insulin-induced hypokalemia.)

2. In a patient with paroxysmal supraventricular tachycardia:

Give an IV push/bolus of adenosine 6mg, in the most proximal IV line literally as fast as you can (because its half life is about 10 seconds)and follow with an IV bolus of 20 ml NS.

By Amrusha Musunuru

References:

1. intravenous injection. (n.d.) Mosby's Medical Dictionary, 8th edition. (2009). Retrieved October 24 2018 from https://medical-dictionary.thefreedictionary.com/intravenous+injection

2. Doyle, G.R., McCutcheon, J.A. (2015). Clinical Procedures for Safer Patient Care. Victoria, BC: BCcampus. Retrieved from https://opentextbc.ca/clinicalskills/

3. RCN Standards for infusion therapy. Fourth edition December 2016 www.rcn.org.uk/direct 4. NHS Foundation Trust: Intravenous Therapy and Peripheral Cannulation Policy Version: 3 August 2017 5. Harrison’s Principles of Internal Medicine 18th Edition: Volume 2