We all have come upon a machine, unplugged, with old gel caked on a probe or worse (see figures 1 and 2 attached), with the images from the patient from the last exam, labeled on the image that was not closed. Now you have to take time before you can even start YOUR ultrasound exam. It is this variation from machine homeostasis, a steady-state of readiness for the next operator, that was the impetus for CLEAR. How can the last operator help the next operator? CLEAR!Figure 1. Curvilinear probe with left over gel

The 20th-century paradigm for ultrasound was a clinician ordered the exam and the patient went to a suite and a sonographer saved images and videos. That sonographer would clean their own machine between patients as there was one machine for the same operator. Their images were read by the imaging specialist and that person relayed back to the clinician the results of the imaging study. These types of ultrasound exams still occur and are billed differently. We call them comprehensive ultrasound exams or referred ultrasound exams.

In contrast, a point-of-care ultrasound (POCUS) exam finds the ultrasound equipment more portable and accessible as the price point has lowered. There is usually one machine and multiple operators who use this same machine. In each case that the operator acquires, interprets and uses the information in clinical management at the patient’s bedside without sending them to an imaging suite. The cleanliness of the machine is up to the person who used it last.

Figure 2CLEAR is the acronym and checklist for the components necessary to keep a machine in good working order for patient care. As a provider of emergency medical services and having a strong interest in ultrasound, I have seen the utility of POCUS in the medical setting. It was not called POCUS in the early days, yet machines and operators have been using, and will continue to use, ultrasound for patient care as this movement grows.

CLEAR is about machine homeostasis, ie, getting the ultrasound machine back to a steady-state to be ready for the next patient. The tagline for CLEAR or machine homeostasis is “The last operator is connected to the next operator; YOU may be the next operator.” The message that is intended is leaving the machine in good working order for the next case that needs ultrasound. CLEAR is 5 simple steps to get the machine ready for use and in good working order:

Clean – Clean the machine. In the era of COVID, this might mean twice (in the room, outside the room, and all surfaces)
Locate the machine – Is it in the correct place?
Energize – Is the machine plugged in? Are all the connections tight and working?
Augment supplies – Do you have enough gel, packets, wipes, other supplies?
Remove patient identifiers – Each case should have an accession number and other metadata, which will need to be removed from the machine before the next use. This can usually be accomplished by ending the exam and starting a new exam.

The purpose of CLEAR is to help the operator learn the steps to perform after doing the ultrasound exam.

These can be simplified as:

Clean the machine.
Locate – Put it back to where it is supposed to reside.
Energize – Plug it In!
Augment – Replace supplies, including adding gel for the next person.
Remove – Patient information. End the exam.

The time is not yet here when all patients, or at least all providers, have their own personal ultrasound machine. In the meantime, we share the machine with other doctors and nurses and others. Remember, when sharing ultrasound machines, CLEAR the machine so the next user/operator is ready to go. Our patients will be thankful, as will the next user. You may be the next user! CLEAR the machine.

To read more about CLEAR, check out the article, “CLEAR: A Novel Approach to Ultrasound Equipment Homeostasis,” in the Journal of Ultrasound in Medicine (Prats MINelson BPGold DLBranditz LDBoulger CTBahner DP. J Ultrasound Med. 2019; 38:767–773. doi: 10.1002/jum.14757. Epub 2018 Aug 19).


David P. Bahner, MD, FAIUM, FAAEM, FACEP, is Professor and Director of Ultrasound in the Department of Emergency Medicine at The Ohio State University College of Medicine.

Interested in reading more tips for ultrasound use? Check out the following posts on the Scan:

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