Identifying orthopedic patients at high risk for venous thromboembolism despite thromboprophylaxis.

Objective: To evaluate risk factors for venous thromboembolism (VTE) despite thromboprophylaxis in major orthopedic surgery patients at a tertiary care hospital.

Methods: Charts from consecutive patients who underwent total hip replacement (THR), total knee replacement (TKR), or hip fracture surgery (HFS) [hip pinning or hemiarthroplasty] from August 1, 1999, to April 30, 2000, at a large Canadian teaching hospital were abstracted using standardized case report forms. Data were collected on patient characteristics, surgical characteristics, and thromboprophylaxis regimen.

Altitude-related hypoxia: risk assessment and management for passengers on commerical aircraft.

Background: Individuals with pulmonary and cardiac disorders are particularly at risk of developing hypoxemia at altitude. Our objective is to describe the normal and maladaptive physiological responses to altitude-related hypoxia, to review existing methods and guidelines for preflight assessment of air travelers, and to provide recommendations for treatment of hypoxia at altitude.

Data Synthesis: Falling partial pressure of oxygen with altitude results in a number of physiologic adaptations including hyperventilation, pulmonary vasoconstriction, altered ventilation/perfusion matching, and increased sympathetic tone.