title: Ventilation - perfusion relationship during hip arthroplasty.
abstract: Ventilation-perfusion relationships (VA/Q) were studied during hip arthroplasty, using a multiple inert-gas elimination technique. True shunt (VA/Q = O) increased on 10 out of 16 prosthesis-anchoring occasions, while "low" VA/Q values (O less than VA/Q less than 0.1) increased on 2 occasions only. Pao2 fell by 1-2 kPa. "High" VA/Q values (10 less than VA/Q less than 100) appeared or increased with the insertion of the prosthesis, while dead space (VA/Q greater than 100) was unaltered. Cardiac output did not change. Pulmonary artery pressure fell and airway peak pressure rose by approximately 2 mmHg. It is possible that the blood flow is forced from non-dependent to dependent lung regions by the altered pressure in airways and blood vessels, creating a "high" VA/Q in upper and shunt regions and a "low" VA/Q in lower lung regions.
mesh_terms: D000368:Aged; D000769:Anesthesia, Inhalation; D005260:Female; D006439:Hemodynamics; D006622:Hip Prosthesis; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D012126:Respiratory Dead Space; D012129:Respiratory Function Tests / Q000379:methods; D013997:Time Factors; D014692:Ventilation-Perfusion Ratio
chemical_list: D010100:Oxygen