Monitoring During Noncardiac Surgery
Circulatory reactions and pulmonary impairment are well-known phenomena during total hip replacement. Usually blood pressure decreases and pulmonary arterial pressure increases slightly directly after insertion of the stem of the prosthesis. Although the impairment is mostly transient, in some cases cardiac arrest and even intraoperative death have occurred. Pulmonary histology of a patient who died intraoperatively directly after the insertion of the prosthesis showed pulmonary fat embolism. Whether bone marrow is displaced out of the femoral cavity by the prosthesis was discussed widely until it was proved for the first time by transesophageal echocardiography (Heinrich et al. 1985). In intraoperative transesophageal echocardiography the right heart is full of contrast directly after the insertion of the prosthesis. We showed the same effect with intramedullary nailing (Fig. 1) (Wenda et al. 1988) and after release of the tourniquet after insertion of a knee prosthesis. The contrasts correlate with a rise in intrafemoral pressure during the surgical procedure. Intraoperative recordings revealed that during total hip replacement the intrafemoral pressure always increases to over 1000 mmHg independent of the venting technique (drainage of bore hole). In osteosynthesis by intramedullary nailing the intrafemoral pressure increases during the drilling process, usually up to 600 mmHg and in some cases to over 1000 mmHg. Two echocardiographic phenomena after the pressure elevation can be distinguished: “snowflakes” are always to be seen after elevation of the intrafemoral pressure, for example after reposition of fractures of long bones, after drilling in the femoral cavity and after insertion of a prosthesis. With considerable elevation of the intrafemoral pressure, large emboli of up to 5 cm can be seen during their passage through the right heart. Our results, raised the question how bone marrow emboli of such size can pass through the vessels of the bone. Indeed, there was a discrepancy between the lumen of the veins and the size of the emboli.
- Wenda K, Ritter G, Degreif J, Rudigier J (1988) Zur Genese pulmonaler Komplikationen nach Marknagelosteosynthesen. Unfallchirurgie 91:432–435.Google Scholar