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Perioperative blood transfusion and blood conservation in cardiac surgery: the Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists clinical practice guideline.

Effect of aprotinin on need for blood transfusion after repeat open-heart surgery

Bleeding Complications Associated With Cardiopulmonary Bypass

Reduction in blood loss and blood use after cardiopulmonary bypass with high dose aprotinin (Trasylol).

Background
Concerns regarding the safety of transfused blood have prompted reconsideration of the use of allogeneic (from an unrelated donor) red blood cell (RBC) transfusion, and a range of techniques to minimise transfusion requirements.

Objectives
To examine the evidence for the efficacy of cell salvage in reducing allogeneic blood transfusion and the evidence for any effect on clinical outcomes.

Search methods
We identified studies by searching CENTRAL (The Cochrane Library 2009, Issue 2), MEDLINE (1950 to June 2009), EMBASE (1980 to June 2009), the internet (to August 2009) and bibliographies of published articles.

Selection criteria
Randomised controlled trials with a concurrent control group in which adult patients, scheduled for non-urgent surgery, were randomised to cell salvage (autotransfusion) or to a control group who did not receive the intervention.

Data collection and analysis
Data were independently extracted and the risk of bias assessed. Relative risks (RR) and weighted mean differences (WMD) with 95% confidence intervals (CIs) were calculated. Data were pooled using a random-effects model. The primary outcomes were the number of patients exposed to allogeneic red cell transfusion and the amount of blood transfused. Other clinical outcomes are detailed in the review.

Main results
A total of 75 trials were included. Overall, the use of cell salvage reduced the rate of exposure to allogeneic RBC transfusion by a relative 38% (RR 0.62; 95% CI 0.55 to 0.70). The absolute reduction in risk (ARR) of receiving an allogeneic RBC transfusion was 21% (95% CI 15% to 26%). In orthopaedic procedures the RR of exposure to RBC transfusion was 0.46 (95% CI 0.37 to 0.57) compared to 0.77 (95% CI 0.69 to 0.86) for cardiac procedures. The use of cell salvage resulted in an average saving of 0.68 units of allogeneic RBC per patient (WMD -0.68; 95% CI -0.88 to -0.49). Cell salvage did not appear to impact adversely on clinical outcomes.

Authors' conclusions
The results suggest cell salvage is efficacious in reducing the need for allogeneic red cell transfusion in adult elective cardiac and orthopaedic surgery. The use of cell salvage did not appear to impact adversely on clinical outcomes. However, the methodological quality of trials was poor. As the trials were unblinded and lacked adequate concealment of treatment allocation, transfusion practices may have been influenced by knowledge of the patients' treatment status potentially biasing the results in favour of cell salvage.

Cell salvage for minimising perioperative allogeneic blood transfusion

In a prospective, randomized study of 20 patients undergoing elective open-heart surgery, up to c. one-third of the total intraoperative and postoperative transfusion requirement could be provided by autologous centrifuged blood. Retransfusion of washed, packed red blood cells freed from cellular debris, heparin and activated clotting factors significantly reduced blood loss during and after surgery. The cell separator is a valuable aid in autotransfusion technique.

Reduction of Postoperative Donor Blood Requirement by Use of the Cell Separator

In 20 patients who underwent open-heart surgery, the plasma concentrations of glucose, insulin, glucagon, growth hormone, free hemoglobin, and cholinesterase were measured before, during and after pulsatile and continuous perfusion. Pulsatile flow was achieved by modification of a roller pump to effect rapid acceleration and slowing. The driving motor was interfaced with a control module to enable ECG-triggered perfusion. In addition to the clinical studies, investigations were performed in 9 dogs to assess the effects of pulsatile and continuous perfusion on liver and pancreas flow during total bypass. During pulsatile perfusion there was a significant increase in insulin which, however, was clearly diminished in relation to glucose levels. The response of the beta-cells was markedly more compromised after continuous than pulsatile perfusion. The secondary postoperative increase in insulin can be accounted for by intravenous administration of glucose and, particularly, after pulsatile perfusion, indicates an almost completely normal response of pancreatic beta-cells. As opposed to the effects of continuous perfusion, the low glucose, glucagon, and growth hormone levels, the insulin increase during and after pulsatile perfusion as well as normal cholinesterase values observed in association with pulsatile perfusion appear to be the result of improved pancreatic and hepatic function. This contention is supported by the experimental finding of significantly increased pancreas and liver perfusion during pulsatile perfusion.

[Clinical and experimental studies on pulsatile and continuous flow during extracorporeal circulation (author's transl)].

In experiments on seven dogs, a fibrin glue was used to seal plastic valves and bioprostheses in the thoracic aorta. Each valves was fixed in place with only four single sutures. Intraoperative and postoperative angiographic checks, with countercurrent aorta filling, gave no indication of perivalvular leak, even after eight weeks. Histologic studies confirmed the angiographic findings and showed only slight changes in the aortic wall. The results indicate that application of fibrin glue, supplementary to conventional suture procedure, may be useful when satisfactory fixation of aortic valves is hampered by pathologic circumstances.

Tissue glue for sealing plastic valves and bioprostheses in the canine aorta.

Anhand des eigenen Krankengutes von 9 Patienten werden Klinik, Diagnostik und Pathologie der Herzmyxome dargestellt. Das klinische Bild wird durch Tumorembolisation, durch hamodynamische Tumorobstruktion und durch Autoimmunreaktion gepragt. Unter den diagnostischen Masnahmen gebuhrt heute der Echokardiographie der Vorrang. Angiographische Untersuchungen sind nur bei unklarem oder negativem echokardiographischen Befund notwendig. Nach Diagnosestellung hat die Operation als Notfalleingriff zu erfolgen. Bei dem operativen Eingriff mussen alle Masnahmen zur Tumorembolisation berucksichtigt werden. Mit guten Langzeitergebnissen ist nur dann zu rechnen, wenn der operative Eingriff vor der Manifestation irreversibler Veranderungen erfolgt. Bei den Myxomen handelt es sich um pathologisch-anatomische echte Herztumoren, die histologisch aus einem myxoiden Stroma und sogenannten Myxomzellen bestehen.

[Clinical findings on heart myxoma (authors' translation)].

Rupture of the aorta frequently occurs in major blunt trauma to the thorax, but few patients survive long enough to develop a chronic aneurysm. A TDMAC-heparin-coated shunt was used for operative procedures on the thoracic descending aorta in 5 patients aged 18--40 years. The lesions constituted in 4 recent ruptures and 1 chronic aneurysm. In 3 cases the aneurysm was resected and replaced with a prosthetic graft. End-to-end aorta sutures were performed in the other two cases. One patient died of renal and pulmonary insufficiency. There have been no complications attributable the shunt. The advantage of this shunt include elimination of the need for systemic heparin, avoidance of hypertension during crosslamping, and adequate perfusion of the distal circulation without an interposed pump. Because of the ease of handling and low risk we consider the use of this shunt the preferred method for operative procedures on the thoracic descending aorta.

W. Saggau

Papers

Reduction of Postoperative Donor Blood Requirement by Use of the Cell Separator

[Clinical and experimental studies on pulsatile and continuous flow during extracorporeal circulation (author's transl)].

Tissue glue for sealing plastic valves and bioprostheses in the canine aorta.

[Clinical findings on heart myxoma (authors' translation)].

[Surgical management of traumatic thoracic aortic aneurysms using the TDMAC-heparin shunt].