This study primarily aimed to describe clinical practices among physicians working in the EDs of two hospitals in French-speaking Switzerland regarding the use of PAR. Over 1 year, PAR was performed in 2.2% of patients admitted to these departments. The three most commonly observed indications (75%) were abdominal pain, suspected ileus and constipation.
When compared against international guidelines, most of the indications for the PAR examinations performed in these departments were inappropriate, exposing the patients to unnecessary radiation. Only 46.2% of the indications complied with the Australian and British guidelines, and these are among the least restrictive [11, 12]. The French HAS and American ACR guidelines are more restrictive and were formulated by a group of health professionals that included radiologists and non-radiologists [13, 14]. According to these guidelines, more than 88% of the PAR examinations were performed for no recognised indication. The magnitude of this overuse may be surprising and possibly results from a lack of local guidelines and poor knowledge among physicians of the examination’s poor diagnostic performance and often downplayed potential risks. In addition, PAR is relatively cheap, delivers a lower radiation dose than standard CT, and has been used for many years as part of old decision algorithms. It has been shown that physicians sometimes find it hard to change their practices, especially when new rules require them to refrain from doing something .
Even though PAR offers no additional benefit than physical examination in non-trauma acute abdominal pain, this indication accounted for 15.3% of PAR examinations performed in our population. Recent guidelines on the management of acute abdominal pain do not include PAR anywhere in their management strategy , nor is PAR deemed useful in suspected appendicitis, biliary colic, or acute pancreatitis .
The indication for PAR in cases of suspected ileus continues to be the subject of debate. Only the French guidelines exclude this indication. The British, Australian, and American organisations consider the examination to be appropriate in this setting, mainly because of its good negative predictive value. In our two EDs, suspected ileus accounted for 28.9% of indications for PAR. In 31.9% of these patients, no other radiological examination was performed, which suggests that PAR made it possible to justifiably rule out the suspected diagnosis. Abdominal CT was the most frequently requested examination in the other cases, exposing the patient to two consecutive radiation sequences. Thus, it is reasonable to wonder whether this strategy is effective and whether the CT examination should not be performed first when ileus is suspected. To avoid excessive, dangerous radiation, low-dose CT might be an alternative for identifying not only the signs of obstruction but also its cause .
Suspected constipation accounted for 30.8% of indications for PAR in our population. This practice is not founded on any scientific evidence, since there exists no correlation between the presence of stools in the colon and a diagnosis of constipation . The diagnosis of constipation should be made based on anamnesis comprising a description of the stools and discomfort affecting quality of life. In our cohort of patients, PAR was followed by another radiological examination (CT or US) in nearly 80% of cases, thereby apparently confirming the poor utility of PAR in such settings.
Even though PAR does no longer belong to the management of renal colic in emergency settings, this indication still accounted for nearly 5% of the PAR examinations performed in our two EDs . Its diagnostic performance and similar radiation dose to PAR make low-dose CT an examination of choice . That said, PAR remains an indication for following patients with radiopaque stones, a setting that accounted for 5.9% of all indications in our cohort.
The diagnostic performance of PAR is generally poorly defined in these various indications and does not prevent additional radiological examinations. More than 70% of the patients were subjected to further examinations, either CT or US. The rate of additional exams was higher at the university hospital than in the private hospital. This could be explained by differences in acuity levels (patients more severe in the university hospital) and by the higher proportion of very elderly patients. In addition, echography is more easily available at the university hospital.
Along with its inadequate diagnostic performance, PAR raises issues of quality of care, costs, and patient safety. The number of radiological examinations performed in EDs has exploded in recent years, exposing patients repeated radiation . According to some specialists, between 1.5 and 2% of cancers diagnosed in the United States may be linked to excessive radiation exposure [24, 25]. Hence, emergency physicians have a duty to prevent unnecessary radiation. Lastly, given that each PAR examination has a mean cost of CHF 110, nearly CHF 200,000 could be saved each year if the most restrictive guidelines are applied.
Therefore, more reasonable and appropriate use of PAR in our EDs would perfectly accord with the principle of “less is more.” Cost reduction is not a priority in this approach, but it may have a positive spin-off effect when it coincides with the patient’s interests. Although PAR is not listed among the top five examinations identified by North American emergency medicine societies in the “Choosing Wisely” programs [26, 27], special efforts need to be made to restrict this examination in Switzerland.
Our study has several limitations. Because of the retrospective nature of our data collection, we were unable to closely analyse the emergency physicians’ clinical rationale. Nor was it possible to identify the indications in more detail beyond what the clinician noted on the radiology prescription slip. In addition, the lack of a real gold standard and the disparity among international guidelines represent an issue for determining the appropriateness of PAR. Besides, the conclusions of the PAR reports were not sufficiently standardized to assess the diagnostic performance of PAR and to compute it’s sensitivity and specificity. Furthermore, the study was conducted in two centres only, a factor that may limit the generalisability of our results. However, given the lack of national guidelines and considerable differences in practice between the private hospital and the public teaching hospital department, we may reasonably suppose that similar variability may be found in other hospitals. Lastly, despite detailed analysis of the records, the information we obtained was insufficient to clearly establish how decisive PAR had been in decision-making or diagnosis. Only a prospective study would enable such analysis. We were likewise unable to identify any characteristics of prescribers that might be predictive of poor use of the examination.