PATHOGENESIS AND PROPHYLAXIS OF CIRCULATORY REACTIONS DURING TOTAL HIP-REPLACEMENT

Circulatory reactions such as a drop in blood pressure, bradycardia, c ardiac arrest, and even intraoperative death after insertion of the st em are well known events during total hip replacement. The present pap er reports bone marrow intravasation after rise of intramedullary pres sure in the femoral cavity during insertion of hip protheses, demonstr ated by intraoperative transesophageal echocardiography, In an animal study, the ultrasound echoes were identified as ''mixed emboli'' consi sting of a core of bone marrow surrounded by thrombus. These results s uggested the use of an intramedullary plug to restrict the intravasati on of bone marrow. A trial was undertaken in 60 total hip replacement operations. The first 30 were performed using the conventional techniq ue without an intramedullary plug. In a second series of 30 operations , an intramedullary plug made of cancellous bone taken from the resect ed femoral head was placed 2 cm below the expected location of the tip of the stem. The cement was applied from distal to proximal by syring e. After implantation of the prosthesis using the conventional techniq ue, a significant drop in blood pressure was observed. In the second s eries, the drop in blood pressure did not occur. In conclusion, it was demonstrated that effective venting of the bone marrow cavity by a bo re hole, and avoidance of compression of the bone-marrow-filled distal femoral cavity by using a plug, results in effective prevention of ci rculatory reactions: no drop in blood pressure occurred. The use of an intramedullary plug is discussed and recommended.