Preoperative testing is used to guide the action plan for patients undergoing surgical and other procedures that require anesthesia and to predict potential postoperative complications. There is uncertainty whether routine or per-protocol testing in the absence of a specific indication prevents complications and improves outcomes, or whether it causes unnecessary delays, costs, and harms due to false-positive results.
We searched MEDLINE® and Ovid Healthstar® (from inception to July 22, 2013), as well as Cochrane Central Trials Registry and Cochrane Database of Systematic Reviews.
We included comparative and cohort studies of both adults and children undergoing surgical and other procedures requiring either anesthesia or sedation (excluding local anesthesia). We included all preoperative tests that were likely to be conducted routinely (in all patients) or on a per-protocol basis (in selected patients). For comparative studies, the comparator of interest was either no testing or ad hoc testing done at the discretion of the clinician. We also looked for studies that compared routine and per-protocol testing. The outcomes of interest were mortality, perioperative events, complications, patient satisfaction, resource utilization, and harms related to testing.
Fifty-seven studies (14 comparative and 43 cohort) met inclusion criteria for the review. Well-conducted randomized controlled trials (RCTs) of cataract surgeries suggested that routine testing with electrocardiography, complete blood count, and/or a basic metabolic panel did not affect procedure cancellations (2 RCTs, relative risks [RRs] of 1.00 or 0.97), and there was no clinically important difference for total complications (3 RCTs, RR = 0.99; 95% confidence interval, 0.86 to 1.14). Two RCTs and six nonrandomized comparative studies of general elective surgeries in adults varied greatly in the surgeries and patients included, along with the routine or per-protocol tests used. They also mostly had high risk of bias due to lack of adjustment for patient and clinician factors, making their results unreliable. Therefore, they yielded insufficient evidence regarding the effect of routine or per-protocol testing on complications and other outcomes. There was also insufficient evidence for patients undergoing other procedures. No studies reported on quality of life, patient satisfaction, or harms related to testing.
There is high strength of evidence that, for patients scheduled for cataract surgery, routine preoperative testing has no effect on total perioperative complications or procedure cancellation. There is insufficient evidence for all other procedures and insufficient evidence comparing routine and per-protocol testing. There is no evidence regarding quality of life or satisfaction, resource utilization, or harms of testing and no evidence regarding other factors that may affect the balance of benefits and harms. The findings of the cataract surgery studies are not reliably applicable to other patients undergoing other higher risk procedures. Except arguably for cataract surgery, numerous future adequately powered RCTs or well-conducted and analyzed observational comparative studies are needed to evaluate the benefits and harms of routine preoperative testing in specific groups of patients with different risk factors for surgical and anesthetic complications undergoing specific types of procedures and types of anesthesia.