This week in my Intermediate Diagnostic Imaging Studies module I attended lectures on Pharmacology and Contrast Media (Messer, 2014). Whilst at Clinical Placement this year I was lucky enough to be able to get to watch some CT scans, MRI scans, Procedures that involved Fluoroscopy and Nuclear Medicine scans. Within some examinations of these imaging modalities, contrast media is introduced into the patient’s body; I found it very interesting to be able to witness what this contrast media did to the patient’s body in real time during the examination and the differences the contrast media made to the images acquired but I also got to witness a patient that had an allergic reaction to the contrast media that was introduced into their body for the examination to occur. Leading on from this experience and our lectures I have this week decided to blog about Contrast media and patient safety within Computed Tomography (CT) Scans, specifically iodine based contrast media.
When a patient is due to undergo a CT scan, sometimes it is necessary for the radiographer to administer a contrast media to the patient prior to the examination. Contrast media is a substance that enhances the appearance of certain structures and fluids within the human body (Howell, 2013) and provides diagnostic information that may not otherwise have been attainable. As discussed by the Pharmaceutical Journal (2012) many, if not all contrast media used within imaging modalities is a prescription only medication (Al-Atroshi, 2012), Prescription only medicines are classified under The Medicines Act 1968 and The Prescription Only Medicines (Human Use) Order 1997 (HCPC, 2014), these medications are required to be prescribed by an appropriate practitioner before they can be used or administered.
Within Computed Tomography examinations it is most common that contrast media be introduced into the patient’s body either orally, intravenously or both. Some examinations that require oral contrast media are:
- Gastrointestinal Tract Examinations such as:
- Small Intestine
- Large Intestine (Radiological Society of North America, 2013)
Some examinations that require intravenously administered contrast media are:
- Internal organs such as:
- Adrenal Glands
- Gastrointestinal Tract
- Arteries and Veins
- Soft Tissues
- Breast (Radiological Society of North America, 2013)
Although it is thought that contrast media is quite safe to administer to a patient (Radiological Society of North America, 2013) and that less than 1% of the population can have an adverse reaction to the drug (Hunt, et al., 2009) it is still very important to be aware and to make the patient aware of the risks. Whilst on Clinical placement with every examination that I witnessed that involved any type of contrast media the radiographer would ask the patient a series of questions, which I now realise formed part of a strict patient safety questionnaire. The patient was asked firstly, a 3 point Identification check – their name, address and date of birth, this was to ensure that the radiographer had the correct patient for the correct examination and that no mistakes would be made. Secondly, if they had ever had a CT scan? if they had ever been given contrast media before – if so had they had a reaction to it? if they were allergic to iodine? had any kidney problems or were asthmatic. If the patient answered yes to any of these questions, a radiologist would be consulted before the examination and administration of the contrast media took place and it would be up to the radiologist weather the drug would be given. Patient with impaired renal problems should be given special considerations before being administered any iodine based contrast media, as kidney nephropathy can be introduced by iodine. When the Contrast media is given intravenously a cannula is placed in a vein in the patients hand/wrist by a qualified professional this cannula is then flushed through with saline solution (which is also a Prescription Only Medication) to ensure that the cannula is correctly in situ. The patient is then positioned within the CT scanner and connected to an injection pump which contains the contrast media – which in a lot of examinations is Omnipaque. The patient is then informed that when the injection starts that they may taste a metallic taste, feel a warm sensation and also feel the need to urinate. The radiographer then leaves the room and controls both the scan and the injection via a computer system.
There is always a chance that a patient could have an adverse reaction to any drug, and the reactions are classed into mild, moderate or serious reactions. There can also be immediate or delayed reactions. In all departments that are administering any contrast media, there will be a contrast reaction kit which includes:
- Epinephrine 1:1000
- Epinephrine 1:10000
- Solu Cortef
- Extra IV Supplies (Fox, 2014)
Also all radiology departments have designated Nurses, Radiologists, Senior Radiographers and individuals who are Life Support trained. There are also resus trolleys situated in every department.
In my experience of a adverse reaction to a contrast media administered intravenously it was quite a high pressured situation for myself having never witnessed a reaction of that sort before and being a student, it was also a scary situation for the concerned patient who was fine at the time of the injection and had no reaction throughout the examination to then be released from the injection to be brought out of the CT scanner and then start to have quite a severe reaction. Although the radiographer knew exactly how to deal with the situation and immediately called a radiologist and a team of nurses who all rushed to the patient’s aid. Although the patient had been asked all the safety questions and had previously had a CT examination with contrast media and had not experienced a reaction.
In conclusion it can be seen that there are risks associated with administration of contrast media within radiography examinations, but it can also be identified that radiography departments are well equipped and sufficiently trained to deal with any reactions that may occur and also it is worth mentioning that the radiographers who administer the contrast media do ask safety questions, and are very well trained that these reactions can occur.
Al-Atroshi, L., 2012. The Pharmaceutical Journal. [Online] Available at: http://www.pharmaceutical-journal.com/opinion/correspondence/contrast-media-are-poms/11106927.article [Accessed 21 October 2014].
Fox, L., 2014. Contrast Reaction Kit Tutorial [Interview] (4 June 2014).
HCPC, 2014. Health and Care Professionals Council – Medicines and Prescribing. [Online] Available at: http://www.hcpc-uk.org.uk/aboutregistration/medicinesandprescribing/ [Accessed 21 October 2014].
Howell, W., 2013. Diagnostic Imaging. [Online] Available at: http://www.diagnosticimaging.com/contrast-agents/communicating-risks-contrast-agents-patients [Accessed 21 October 2014].
Hunt, C., Hartman, R. & Hesley, G., 2009. Frequency and severity of adverse effects of iodinated and gadolinium contrast materials: retrospective review of 456,930 doses. American Journal of Roentgenology, 193(4), pp. 1124-1127.
Messer, S., 2014. Contrast Media. [Sound Recording] (UWE).
Radiological Society of North America, 2013. RadiologyInfo. [Online] Available at: http://www.radiologyinfo.org/en/safety/index.cfm?pg=sfty_contrast [Accessed 21 October 2014].