Clinical orthopaedics and related research
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Clin. Orthop. Relat. Res. · Feb 1993
The use of lower tourniquet inflation pressures in extremity surgery facilitated by curved and wide tourniquets and an integrated cuff inflation system.
Use of the lowest possible cuff inflation pressure should minimize the pathogenic effects of compression beneath the pneumatic tourniquet. Curved tourniquets (designed to fit conically shaped limbs) and wider tourniquets were associated with significantly lower arterial occlusion pressure (AOP) than standard, straight tourniquets on the arms and legs of 26 normal volunteers. ⋯ Incomplete hemostasis was associated with elevated systolic blood pressure in several cases, but acceptable surgical hemostasis was achieved by incremental increase of the cuff inflation pressure. Curved cuffs, wide cuffs, and an integrated cuff inflation system should facilitate the use of lower tourniquet inflation pressures in extremity surgery.
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Clin. Orthop. Relat. Res. · Feb 1993
Methylmethacrylate plasma levels during total hip arthroplasty.
Methylmethacrylate (MMA) plasma concentrations were measured in 11 patients scheduled for total hip arthroplasty. After acetabular and after femoral cement implantation, sequential blood samples were withdrawn from pulmonary and radial artery catheters. The peak concentration of MMA (mean +/- standard error of the mean) in pulmonary artery blood occurred two minutes after cement implantation and was significantly higher after acetabulum (5.0 +/- 1.3 micrograms/ml) than after femoral cement insertion (1.9 +/- 0.6 micrograms/ml). ⋯ The initial half-life was 0.3 +/- 0.1 minutes, and the terminal half-life was 3 +/- 0.7 minutes. The areas under the curve (AUC) were determined for pulmonary (AUCpa) and radial (AUCra) plasma samples, and the ratio (AUCpa - AUCra)/AUCpa was computed: 55.1 +/- 7.8% of MMA was cleared during the transpulmonary passage. These results demonstrate that: (1) MMA could be determined after each cement implantation, (2) MMA plasma concentrations were higher after acetabulum than after femoral cement implantation, and (3) the half-life is short and the total pulmonary clearance is high.