Blood saving in orthopaedic surgery

Abstract

A substantial blood loss frequently accompanies total hip and knee replacement surgery. This is a potential health risk and associated with increased need for allogenic blood transfusions. Blood transfusions in turn may transfer blood-borne infections as well as cause allergic reaction and immunomodulatory effects (Bierbaum 1999, Blumberg 1986, 1996). In addition bank blood is often in short supply. Consequently there is a growing interest focused on methods which may reduce blood loss in orthopaedic surgery and thereby minimise transfusion requirements. In this thesis, based on 5 papers, new and established methods are studied to extend our knowledge about how to reduce blood loss in prosthetic hip and knee surgery.

In the first study (I) we compared the diathermy knife to the scalpel in 67 patients scheduled for total hip replacement (THR). In 33 patients, the scalpel was used throughout the operation and diathermy solely for coagulation of bleeding points. In 34 patients, diathermy knife was used. No significant differences occurred between the groups in blood loss or transfusion requirements.

In study II 74 patients subjected to total knee replacement (TKR) were investigated. InTKR a tourniquet is routinely used to achieve blood less field. It has been debated if it is possible to achieve better hemostasis by deflating the tourniquet during surgery for coagulation of bleeding points. In 46 patients, the tourniquet was deflated at end of surgery. In the other group of 39 patients, the tourniquet was kept inflated until end of surgery and after application of a compressive dressing. No significant differences between the groups in total blood loss or functional outcome were found.The tourniquet may safely be inflated throughout the surgical procedure.

Furthermore the importance of lateral vs. supine positioning of the patient during THR was tested in 81 patients. Standardised operative technique was used. In lateral position the mean intraoperative blood loss was lower 509 (316) m] compared to 775 (316) m] in tile supine group (p<0.001).Total blood loss was also lower 1273 (458) ml in the lateral group vs. 1472 (407) mI in the Supine (p<0.05). Reduced hydrostatic blood pressure in the wound and hence reduced bleeding from small vessels most probably explains the difference in blood loss. If reduced blood loss is the endpoint, the lateral position is recommended when performing THR.

The postoperative drainage after THR was evaluated in study IV. A patient group (n= 12) with no drains was compared to a group with two drains (n= 10). Tile postoperative hematoma volume was measured with a scintigraphic method using a gamma camera and erythrocytes labelled with an isotope. The results clearly showed that the postoperative hematoma volume was not reduced in the group with drains. However transfusion requirements in the drained group was significantly higher, 822 (813) ml compared to the non-drained group, 234 (290) mI, p<0.05. It is concluded that drains do not reduce postoperative hematoma volume but blood loss is increased.The drains counteract a tamponade effect in the haematoma cavity.

Amino acid infusion was in earlier studies shown to reduce the fall in temperature that occurs during anaesthesia. In addition reduced hypothermia is shown to reduce blood loss. In study V we compare a group of patients (n=23) receiving amino acid infusion before THR with a control group (n= 25) receiving Ringer's solution.The patients had spinal anaesthesia. It was shown that amino acid infusion in the perioperative period reduces the fall in body core temperature and that the blood loss is reduced during surgery for THR, 516 (272) all in the amino-acid group and 702 (344) rill controls, p<0.05. The reason for reduced blood loss is not clarified, but it is known that the function of the coagulation cascade and platelets is reduced in patients with low body core temperature.

In summary we have demonstrated that it is possible to reduce blood loss in THR by giving the patient amino acid infusion, placing the patient in lateral position and avoid postoperative drainage.The use of electro cautery for dissection, however, did not influence bleeding. In TKR. the tourniquet safely can be used inflated during the whole procedure without risking increased blood loss or bleeding complications.