Prolonged immobility associated with long-distance air travel predisposes patients to deep vein thrombosis (DVT) and venous thromboembolism (VTE). A recent systematic review found that long-haul flights of 8 hours or more increased the risk of thrombosis, with asymptomatic DVT developing in up to 10% of such travelers. The prolonged immobility and hypercoagulable state associated with major surgery (especially lower-extremity orthopedic or pelvic surgery) may add to this risk. Therefore, patients who travel long distances to have surgery may be at high risk for perioperative venothrombotic events. Indeed, in a large retrospective review at Mayo Clinic, patients traveling more than 5,000 km had a higher rate (≈30×) of perioperative VTE than those traveling a shorter distance before surgery. In that study, those in whom VTE developed also were younger, had VTE development significantly earlier in the postoperative course, had a higher American Society of Anesthesiologists (ASA) physical status classification, and were more likely to be smokers. Therefore, all perioperative physicians should be aware of this risk and must be ready to recognize even the subtle signs and symptoms of DVT and pulmonary embolism (PE) to avoid catastrophic perioperative complications of PE.

Several mechanisms have been proposed by which long-haul air travel may contribute to the risk of VTE. Long periods of relative immobility (also called “economy class syndrome”), especially in patients sitting in nonaisle seats; obstruction of venous return as a result of compression of popliteal veins at the edge of the seat; exposure to hypobaric, low-humidity air; the stress of travel; hypercoagulability (seen even in healthy volunteers exposed to a simulated airplane cabin environment); and possibly dehydration resulting from decreased fluid intake or excessive use of alcohol during the trip all may be additive risk factors.

Morbidity and mortality from VTE is attributable primarily to PE, which is sometimes difficult to diagnose in the perioperative period because
clinical manifestations are often nonspecific. Manifestations include dyspnea, substernal chest pain, syncope, tachycardia or even cardiac dysrhythmias, and worsening of pre-existing congestive heart failure. Pleuritic chest pain and hemoptysis are seen only when pulmonary infarction has occurred. Physical examination may indicate lower-extremity swelling resulting from obstruction of venous outflow by thrombus in large vessels.