Update on Preprocedure Testing

Preoperative Radiologic Studies

The preoperative clinician should target ordering of preoperative radiology studies to specific issues raised by the patient’s history and physical examination. For example, concern over the status of current heart failure or active pulmonary infection may prompt the preoperative clinician to order chest radiographs. In addition, radiologic studies may be indicated to define cervical spine or tracheal anatomy of concern so that safe airway management can be provided. In these instances, the ordering preoperative clinician needs to ensure that accountability for review of the results of these studies exists in the perioperative workflow.

There needs to be a clear definition between radiologic studies ordered by the surgeon to define indications for the operation and studies ordered by the preoperative clinician for the purpose of preoperative assessment and management. For example, surgeons may order chest radiographs as part of a general screening in patients undergoing procedures for cancer diagnosis. The ordering physician is responsible for reading and acting on the results of the test. If systems to ensure accountability are not adequate, patients may have abnormal chest radiograph results present in the system that have not been reviewed and acted on by the ordering clinician. Special attention needs to be paid when there are short intervals between surgical evaluation and procedure date, in which all test results may not have been adequately reviewed. It is prudent for institutions to develop standards to clearly delineate accountability for preoperative test review; for example, at the Brigham and Women’s Hospital it is reinforced with a documented policy that the clinician who orders the study is responsible for any result. These measures should be taken to avoid the unfortunate circumstance in which, for example, a nodule is present on a preoperative chest radiograph that was ordered but not reviewed, and the patient returns later with a cancer diagnosis.

The lack of value of screening radiographs has been documented in a number of studies. In existing pulmonary conditions such as chronic obstructive pulmonary disease (COPD), it is unlikely the expected abnormalities revealed on a preoperative chest radiograph will affect perioperative management. In a literature review of articles published between 1966 and 2004, an association between preoperative screening with chest radiographs and a decrease in perioperative morbidity and mortality could not be established. Up to 65% of the changes seen were associated with chronic disorders and had little impact on management. Postoperative pulmonary complications did not differ between patients who had preoperative screening chest radiographs and those who did not. These authors concluded that although the prevalence of chest radiograph abnormalities increases with age and risk factors, most abnormalities found were chronic and were not shown to affect anesthetic management or perioperative outcome. Chest films ordered because of concerns about the possibility of acute heart failure or acute pneumonia were the only possible exceptions, which led to the authors’ recommendation that asymptomatic patients do not warrant screening chest radiographs, regardless of age.

In contrast, the American College of Physicians considers that chest radiographs may be reasonable in patients older than 50 years who are undergoing abdominal aortic aneurysm (AAA), upper abdominal, or thoracic surgery. The American Heart Association (AHA) suggests that patients with severe obesity (body mass index > 40 kg/m ² ) and one or more risk factors for cardiovascular disease, such as diabetes, smoking, hypertension, or hyperlipidemia, or poor exercise tolerance have a chest radiographs performed preoperatively. The thought in these cases is that screening radiographs may reveal undiagnosed heart failure or abnormalities suggestive of significant pulmonary hypertension. Nevertheless, there are no studies supporting the fact that these recommendations have been correlated with a change in perioperative outcomes. Therefore the preoperative anesthesiologist should only order chest radiographs when suspicion of an acute process exists. The surgeon may decide to order a preoperative chest radiograph for other reasons, including as part of an overall screening for metastatic disease, but should be responsible for reviewing and acting on the results.

The Canadian Anesthesiologist Society guidelines recommending that preoperative chest radiographs not be done in asymptomatic patients are supported by a systematic review noting that most abnormalities found are chronic and the majority are cardiomegaly and COPD. Abnormalities, with the possible exception of acute heart failure, were not found to affect anesthetic or surgical management or perioperative outcome. The American College of Radiology recommends against preoperative chest x-rays in otherwise healthy ambulatory patients with a normal physical examination. The Task Force of the American Society of Anesthesiology has reviewed the evidence on preoperative chest radiographs. This group states that although chest radiograph abnormalities may be more frequent in patients who are older, have stable COPD, have stable cardiac disease, smoke, or have resolved recent upper respiratory infections, there is no evidence that chest radiograph results in these patients will affect outcome or management.