This patient is scheduled for cataract extraction, which is a low-risk surgical procedure and requires no specific diagnostic studies for preoperative evaluation. For these and other low-risk invasive procedures, including hernia repairs and superficial surgeries, routine preoperative diagnostic testing is very low yield and unlikely to affect perioperative management. In such situations, diagnostic testing should only be ordered if it is otherwise indicated outside of the preoperative context (such as ordering a urinalysis in a patient with dysuria).
Preoperative chest radiography rarely adds useful information in the evaluation of patients at risk for perioperative pulmonary complications. At least four systematic reviews and guidelines recommend against routine preoperative chest radiography in patients without suspicion of intrathoracic disease.
Routine assessment of blood counts or coagulation parameters is not indicated for most surgical procedures, including low-risk eye surgery. Evaluation for adequate hemostasis requires only a thorough history and physical examination except for procedures in which even a small amount of bleeding could be catastrophic (for example, intracranial surgery). A leukocyte count is indicated only if there is a concern for bone marrow abnormalities or infection. Hemoglobin and hematocrit are reasonable to obtain in patients with findings suggestive of anemia or undergoing large blood loss surgery (such as total hip arthroplasty).
Electrocardiography is not routinely indicated for any surgery and should only be obtained prior to low-risk surgery if there is concern for new or evolving cardiac disease. According to the American College of Cardiology/American Heart Association guidelines, patients with coronary artery disease, arrhythmias, or coronary artery disease equivalents should have electrocardiography performed within 30 days of non–low-risk surgery.
Serum electrolytes and creatinine measurements are not necessary before low-risk surgery unless the patient has signs or symptoms suggestive of active disease that would affect these values (such as vomiting or diarrhea). Even for patients with chronic diseases or medications that may affect kidney function or electrolytes, assessment before low-risk procedures is necessary only if there has been a significant change in the patient's status (such as a recent increase in diuretic dose).