In Case of Depressurization, Secure Your Oxygen First: A Case of Clevidipine-Induced Hypoxemia

Introduction: Clevidipine is an ultrashort-acting dihydropyridine calcium channel blocker commonly used for rapid blood pressure control in critical care, especially post-cardiac surgery. Hypoxic Pulmonary Vasoconstriction (HPV) causing ventilation-perfusion (V/Q) mismatch and subsequent refractory hypoxemia is an exceedingly rare compilation with only 2 other cases being reported in literature.


Description: A 63-year-old man with Chronic Obstructive Pulmonary Disease (COPD), chronic respiratory failure, and coronary artery disease presented with a chief complaint of exertional angina. Left heart catheterization revealed multivessel CAD for which he underwent quadruple coronary artery bypass grafting (CABG). He was admitted to the ICU for post operative monitoring and started on clevidipine drip for hypertension. The patient developed acute hypoxemia with PO₂/FiO₂ ratio dropping precipitously from 297 to 91 within hours, which did not improve despite maximal ventilatory support. Imaging ruled out other acute pathologies like pneumonia, pneumothorax, atelectasis etc. With no other reversible cause identified, clevidipine was discontinued due to concern for impaired HPV and intrapulmonary shunting. Within 24 hours, oxygenation improved (PO₂/FiO₂ rose to 240), with the patient being extubated on POD-4.


Discussion: HPV is a physiological process where pulmonary vasculature constricts in response to low oxygen levels, which then redirects pulmonary blood flow away from poorly ventilated alveoli to optimize gas exchange. Vasodilators like clevidipine confound this protective mechanism by increasing intrapulmonary shunting. This leads to hypoxemia which reverses promptly after drug discontinuation as evidenced by our case.
Underlying comorbidities that could independently explain hypoxemia often lead to a delayed diagnosis of drug induced complications. This necessitates a high index of clinical suspicion. In such cases, a therapeutic trial of cessation may serve as a low‑risk, cost‑effective first step—potentially obviating the need for more invasive or expensive diagnostic evaluations for other causes of hypoxemia. Additionally, it is important to evaluate whether a safe therapeutic dose of clevidipine can mitigate the risk of ventilation-perfusion (V/Q) mismatch and intrapulmonary shunting.