CASE Patient questions need for preoperative tests
A healthy 42-year-old woman (G2P2) with abnormal uterine bleeding and a 2-cm endometrial polyp is scheduled for hysteroscopic polypectomy. After your preoperative clinic visit, the patient receives her paperwork containing information about preoperative lab work and diagnostic studies. You are asked to come into the room because she has further questions. When you arrive, the patient holds the papers out and asks, “Is all this blood work and a chest x-ray necessary? I thought I was healthy and this was a fairly simple surgery. Is there more I should be worried about?”
How would you respond?
The goal of preoperative testing is to determine which patients may be at an increased risk for experiencing an adverse perioperative event, taking into account both the inherent risks of the surgical procedure and the health of the individual patient. In the literature, the general consensus is that physicians rely too heavily on unnecessary laboratory and diagnostic testing during their preoperative assessment.1 More than 50% of patients who underwent preoperative evaluation had at least 1 unindicated test.2 These tests may result in a high frequency of abnormal findings, with less than 3% of abnormalities having clinical value or leading to a change in management.3
With health care costs accounting for almost 20% of the gross domestic product in the United States (totaling about $3.5 billion in 2017), performing unindicated preoperative testing contributes to the economic burden on health care systems, with an estimated cost of $3 to $18 million annually.4,5 In addition, unindicated tests can increase patient anxiety and necessitate follow-up testing, possibly exposing physicians to increased liability if abnormal results are not adequately investigated.6
It is time to rethink our use of routine preoperative testing.
Which tests to consider—or not: Evidence-based guidance
Professional societies, including the American Board of Internal Medicine’s Choosing Wisely campaign, promote a move away from routine testing to avoid unnecessary visits and studies. In addition, the American Society of Anesthesiologists (ASA) has published recommendations to guide preoperative testing.7 To stratify patients’ surgical risk according to their pre-existing health conditions, the ASA created a physical status classification system (TABLE 1).8
In addition to individual patient characteristics, some guidelines similarly stratify surgical procedures into minor, intermediate, and major risk. The modified Johns Hopkins surgical criteria allocates surgical risk based on expected blood loss, insensible loss, and the inherent risk of a procedure separate from anesthesia (TABLE 2).9 Despite these guidelines, physicians responsible for preoperative evaluations continue to order laboratory and diagnostic tests that are not indicated, often over concerns of case delays or cancellations.10,11
The following evidence-based recommendations provide guidance to gynecologists performing surgery for benign indications to determine which preoperative studies should be performed.
Serum chemistries
Basic metabolic panel (BMP). In both contemporary studies and earlier prospective studies, a preoperative BMP has a low likelihood of changing the surgical procedure or the patient’s management, especially in patients who are classified as ASA I and are undergoing minor- and intermediate-risk procedures.12,13 Therefore, we recommend a BMP for patients in class ASA II or higher who are undergoing intermediate-risk or major surgery.14
Thyroid function. A basic tenet of preoperative evaluation is that asymptomatic patients should not be diagnosed according to lab values prior to surgical intervention. Therefore, we do not recommend routine preoperative thyroid function testing in patients without a history of thyroid disease.10 For patients with known thyroid disease, a thyroid stimulating hormone (TSH) level should be evaluated prior to major surgery, or with any changes in medication dose or symptoms, within the past year.15
Liver function tests (LFTs). Routine screening of asymptomatic individuals without risk factors for liver disease is not recommended because there is a significantly lower incidence of abnormal lab values for LFTs than for other lab tests.16 We recommend LFTs only in symptomatic patients or patients diagnosed with severe liver disease undergoing intermediate-risk or major procedures.14
Hemoglobin A1c (HbA1c). Poorly controlled diabetes is a risk factor for poor wound healing, hospital readmission, prolonged hospitalization, and adverse events following surgery.17 We recommend that HbA1c levels be drawn only for patients with known diabetes undergoing intermediate-risk or major surgery who do not have an available lab value within the past 3 months.14
Continue to: Hematologic studies...