The effectiveness of interventions to prevent or reduce Contrast Media Extravasations among patients undergoing computerized tomography scanning: a systematic review protocol

Review question/objective The primary objective of the review is to identify the effectiveness of interventions to prevent or reduce contrast medium extravasation in patients undergoing Computerized Tomographic examination. The specific review question is: What is the effectiveness of methods to prevent or reduce Contrast Media Extravasations among patients undergoing computerized tomography scanning? Background Computed tomography (CT) is a frequently conducted radiological examination and the number of CT examinations continues to increase globally. For instance, in the United States, the number of CT scans has more than doubled in 10 years, reaching 275 examinations per 1000 people in 2011.1 This trend is likely to continue in the coming years due to the ageing of the population and the resulting increase in chronic diseases, such as cardiovascular diseases, cancer and metabolic pathologies.2 CT scanning has become indispensable for the diagnosis and follow up of a large variety of diseases because of higher sensitivity and specificity compared to classical X-ray exams.3 This is the inevitable result of its capacity to produce images of axial slices from which it is possible to make volumetric reconstructions in three dimensions,3 or even in four dimensions with the creation of multiple cardiac phase cine loops.4 Radiological examination by CT scan produces an image quality that is continually improving and allows the visualization of hard tissue, such as bone, as well as parenchyma, such as liver.5 In order to enhance the differentiation of the anatomy and abnormal structures, particularly for the vascular system and viscera, iodinated contrast medium is routinely injected intravenously to the patient.6 These contrast media allow differentiating between venous and arterial tissue phases.5 Evidence indicates about 50% of CT exams use contrast medium, making it a widespread practice.7 Contrast media are traditionally administered intravenously through manual or drip injection methods. However these methods have been found to be variable in terms of injection flow rates and may negatively affect specific organ enhancement.8 Increasing numbers of radiology departments are equipped with automated power injectors for administration of contrast materials through peripheral venous catheters at constant flow rate allowing specific angiographic and visceral enhancement.9 The injection of radiographic contrast agents facilitates increased diagnostic or prognostic accuracy, with clearer tissue differentiation or intravascular imaging by vessel opacification.5 Nevertheless, contrast media have side effects, such as allergic-like reactions, vasovagal reaction, cardiac arrhythmias or pulmonary edema.8,10 Furthermore, a well-recognized important potential complication is subcutaneous extravasation11, which is defined as an accidental leakage of the injected fluid in the surrounding tissue.12 Extravasation constitutes an increased risk due to expanded use of power injectors compared to manual or drip injection.13,14 Because contrast media agents are vesicant, they may cause injuries to the patients. In the best cases, the adverse effects may be mild with no severe sequelae, e.g. inflammatory reactions,14,15 but they nonetheless cause pain and discomfort to the patient that may persist in the long term. However major adverse consequences such as skin ulceration, soft-tissues necrosis or compartment syndrome have been documented.16 Serious effects are a risk, whether ionic or non-ionic contrast medium is injected.16 When extravasation occurs, close patient monitoring is required to evaluate symptoms because the reaction manifests itself several hours after injection and the timing and duration of subsequent sequelae may vary substantially.8 The treatment of serious extravasation may require a surgical fasciotomy, skin grafting or even amputation.8,14,17,18 Furthermore, if complications associated with extravasation occur, the exam may be delayed and, a new intravenous access has to be placed - inducing additional stress to the patients on top of the known stressors associated with a CT scan.19-21 Sometimes the CT examination must also be repeated, which exposes the patient to an additional radiation dose and contravenes the “As Low As Reasonably Achievable” (ALARA) principle of radiation protection.22 The realization of a new injection increases the cost due to the material used19, the radiology personnel required and scanner utilization. Furthermore it reduces radiological department workflow.19 Accordingly, the financial and social implications of such undesirable events are not negligible. There are several strategies to prevent the extravasation that are related to the (i) healthcare professionals, and (ii) technical tools used. Concerning healthcare professionals, IV administration may be performed by persons from different professions: they may be nurses, radiographers or radiologists. Researchers have investigated whether this factor might affect extravasation.23 Additionally, training of the healthcare professional might be an important variable, and notably to ameliorate the patient risk factors.9,24 Indeed, it has been identified that certain patient characteristics may induce an increased risk of extravasation. This is the case for patients with diabetes mellitus, venous thromboembolism, or cancer, or patients with altered communication (young children, elderly, debilitated or unconscious patients).10,8,13,14,25 Secondly, in relation to technical prevention methods, several have been reported in the literature. These include strategies related to the characteristics of contrast media (including volume, concentration, viscosity, temperature, and rate of administration)6, 8, 13, 23, 26-28 as these have been shown to increase or reduce extravasation (rate and volume). Similarly, the injection technique per se (patient injection site, preparation room)13, 14, 25, 26, 28 and the material used for injection (catheter gauge, cannulas, butterfly, venflon)6, 13, 23, 25, 26, 28 may affect extravasation. Finally reduction of extravasation rates could potentially be improved through the use of newly developed extravasation detection apparatus (detection device: ultrasound, radiofrequency).29 Knowing the effectiveness of these strategies is especially important for radiology personnel because they can use, in their clinical practice, the most appropriate to prevent extravasation. This should also help to improve the patient experience when undergoing a scanner examination. Primary research articles have been published on the subject and their number has increased in recent years. In addition, guidelines have been published by learned societies, but they are not based on systematic literature reviews. Following a search in the JBI Database of Systematic Reviews and Implementation Reports, Cochrane Library, Medline and Trip database, the authors found no systematic review evaluating the scientific evidence of these strategies. It appears that it is worthwhile to conduct a systematic review on the subject of the prevention and reduction of contrast media extravasation during CT exam.