Coronavirus Disease 2019 (COVID-19)

Timing after infection is individualized, not a fixed number - Do not take a still-infectious patient to an elective case. Beyond that, the decision weighs the severity of the COVID-19 episode, whether symptoms are ongoing, and the complexity of the surgery against the harm of delaying. The interval guidance has moved more than once, so pull the current ASA/APSF joint statement rather than a remembered number.

Grade the residual lung rather than assume it recovered - Room-air saturation and a straightforward exercise-tolerance history catch most of it. In anyone who needed mechanical ventilation, high-resolution CT and repeat pulmonary function testing are the studies that answer the question.

The thrombotic burden is the quiet risk - Severe inflammation, cytokine release, and endothelial injury produce a genuine hypercoagulable state: elevated D-dimer, thrombocytopenia, mildly prolonged PT, and raised fibrinogen and von Willebrand factor. A D-dimer above 1 mcg/mL was seen in 42% of patients and 81% of those who died, carrying an 18-fold mortality risk. Autopsy series found deep venous thrombosis in 58% of patients in whom it had never been suspected, and ischemic stroke runs about 1% to 3%. Keep sequential compression running, keep them warm and euvolemic, and take new unexplained hypoxia or a cold limb seriously.

Look for cardiac injury before you need it - Myocardial damage comes from raised cardiometabolic demand plus hypoxia, from plaque rupture off the inflammatory and catecholamine surge, and from frank coronary thrombosis. Troponin and a 12-lead ECG are the screen; transthoracic echo is indicated for heart failure, arrhythmia, ECG changes, or new cardiomegaly on chest film or CT.

Intubation and extubation are aerosol-generating - Full PPE for a known-positive patient means eye protection, face shield, gloves, and an N99 or FFP3 respirator; aerosol-generating procedures add a powered air-purifying respirator hood and waterproof gown. Keep OR staff to a minimum, have everyone not directly involved in airway management wait outside during intubation and extubation, and hold room disinfection until 15 minutes after the patient leaves.

Emergence gets less thought than induction and should not - Nearly all the published attention went to reducing exposure during intubation; the coughing patient at extubation has been studied far less. Plan the emergence deliberately instead of inheriting it.

Assume unknown status is positive - For aerosol-generating procedures, treat an untested patient as infected rather than sorting it out afterward.

Prone positioning for refractory hypoxemia - Proning lowers abdominal pressure on dependent lung, improves ventilation-perfusion matching, distributes alveolar ventilation more evenly, and reduces ventilator-induced lung injury. It takes four to five people. Watch pressure points and skin breakdown, keep IV lines and devices from lying under the patient, and have a rehearsed plan to get them supine fast for accidental extubation, endobronchial migration, a dislodged line or chest tube, or arrest.

SARS-CoV-2 enters cells when its spike protein binds the angiotensin-converting enzyme 2 (ACE2) receptor on respiratory epithelium and is primed by host transmembrane serine protease 2. Most infections stay mild, but roughly 5% to 8% of patients develop hypoxia, bilateral infiltrates, and reduced lung compliance requiring noninvasive or mechanical ventilation. In severe disease an excessive cytokine release drives acute respiratory distress syndrome (ARDS), a hypercoagulable state, maladaptation of the ACE2 pathway, end-organ hypoperfusion, septic shock, and multiorgan failure. ACE2 also sits on enterocytes, cholangiocytes, and pancreatic islet cells, which is why gastrointestinal and hepatic involvement turn up.

For anesthesia the durable picture is not the acute illness but what it leaves behind: a lung with impaired compliance and gas exchange, and an injured endothelium carrying a real thrombotic burden. Both outlast the infection.