Before surgery in patients with ankylosing spondylitis, which preoperative test is particularly recommended to assess respiratory risk?

Before surgery in patients with ankylosing spondylitis, which preoperative test is particularly recommended to assess respiratory risk?

• A. Echocardiography
• B. Renal function tests
• C. Blood tests
• D. Pulmonary function testing

Answer: (D)

Ankylosing spondylitis often causes a restrictive pattern of lung disease because the spine and chest wall become less able to expand. Before surgery, it’s crucial to know how much ventilatory reserve the patient has, since reduced reserve increases the risk of postoperative pulmonary complications. Pulmonary function testing directly measures this reserve by assessing lung volumes, airflow, and gas exchange. It typically includes spirometry (to get measures like FEV1 and FVC and their ratio), lung volumes (such as total lung capacity and residual volume), and diffusion capacity (DLCO). This combination reveals whether the patient has restricted volumes, reduced capacity, or impaired gas transfer, which informs anesthetic planning and postoperative respiratory care, such as the need for aggressive chest physiotherapy or early incentive spirometry. Other tests like echocardiography, renal function tests, or routine blood tests don’t quantify lung function or reserve, so they don’t provide the specific respiratory risk assessment needed in this scenario.

Ankylosing spondylitis often causes a restrictive pattern of lung disease because the spine and chest wall become less able to expand. Before surgery, it’s crucial to know how much ventilatory reserve the patient has, since reduced reserve increases the risk of postoperative pulmonary complications. Pulmonary function testing directly measures this reserve by assessing lung volumes, airflow, and gas exchange. It typically includes spirometry (to get measures like FEV1 and FVC and their ratio), lung volumes (such as total lung capacity and residual volume), and diffusion capacity (DLCO). This combination reveals whether the patient has restricted volumes, reduced capacity, or impaired gas transfer, which informs anesthetic planning and postoperative respiratory care, such as the need for aggressive chest physiotherapy or early incentive spirometry.

Other tests like echocardiography, renal function tests, or routine blood tests don’t quantify lung function or reserve, so they don’t provide the specific respiratory risk assessment needed in this scenario.