1) Transfusion pro and con
Anaemia is a potent risk factor for mortality and morbidity in surgical patients, and its management has begun to shift away from allogeneic blood transfusion in recent years.
Adverse effects of anaemia have been demonstrated specifically in the perioperative setting. A preoperative hemoglobin concentration of less than 6 g/dL increases the risk of death 30 days after surgery by a factor of 26 relative to a concentration of 12 g/dL or greater in surgical patients who declined blood transfusion for religious reasons
The safety of the blood supply has improved. Sophisticated testing has led to a decline in the risk of transfusion-related transmission of HIV, the hepatitis C virus, and the hepatitis B virus.
But there is a continual rise in fatal TRALI (transfusion-related acute lung injury) cases in the United States from 2001 to 2006. TRALI occurred in more than half of all transfusion-related fatalities reported to the FDA in 2006, a higher number than for any other single cause
At the same time, there is evidence that hemovigilance can reduce the risk of TRALI. TRALI accounted for 6.8% of all transfusion-related adverse events reported in the United Kingdom during the period 1996–2003. This proportion declined to just 1.9% in 2006
Finally, despite the progress in screening blood for HIV and the hepatitis viruses, some additional infections now must be considered when assessing blood supply safety. These include diseases newly recognized as being transmissible by blood, for which blood donor screening is not currently available, or that are newly emergent infections for which the potential for spread by transfusion is unknown.
The Transfusion Requirement in Critical Care (TRICC) trial was conducted in 838 critically ill patients in intensive care settings. Patients were randomized to a strategy of either liberal transfusion (which begun when hemoglobin fell below 10 g/dL) or restrictive transfusion (which begun when hemoglobin fell below 7 g/dL). The restrictive strategy was associated with significantly lower mortality in two subgroups: patients with myocardial infarction and patients with pulmonary edema.
Rao et al. performed a meta-analysis of three large international trials of patients with acute coronary syndromes to determine whether blood transfusion to correct anaemia in this setting was associated with improved survival
]. They found significantly higher mortality among patients who underwent transfusion compared with those who did not, prompting them to urge caution in the use of transfusion to maintain arbitrary hematocrit levels in stable patients with ischemic heart disease in an observational cohort study of 11,963 patients who underwent isolated coronary artery bypass graft surgery, each unit of red blood cells transfused was associated with an incrementally increased risk of adverse outcome (eg, mortality, renal injury, need for ventilator support, lengthened hospital stay, infection)
]. The latter study found that transfusion was the single factor most reliably associated with increased risk of postoperative morbidity
2) Techniques of Blood Conservation
In 2005 we reported our initial experience in 200 Jehovah’s witness patients undergoing cardiac surgery
]. Since then , we have had to deal with the withdrawal of Aprotinin which we thought was an important weapon in our therapeutic armentarium. The change of protocol by 1 g at induction and 1 g at the end of bypass of EACA did not alter our final results and this change did not alter in our bleeding control in any way. Fifty years of research into the effectiveness and safety of prophylactic use of antifibrinolytics for cardiac surgical patients demonstrate that aprotinin and EACA reduce postoperative blood loss and consequently , the requirement for blood transfusions and reoperation for bleeding compared to placebo or treatment. Traditionally , evidence in favor of EACA is not compelling , but in head-to-head comparisons there is an increased risk of death among patients receiving aprotinin compared to those on lysine analog as indicated by the BART trial. All of these have been demonstrated on huge series including over 12,000 patients. These differences did not appear in our two small groups. The aim of all efforts to reduce the need of allogeneic blood transfusions is to avoid associated risks. There should particularly be a favourable effect according to the rate of transfusion-transmitted virus infections and immunological side-effects. The acceptance of an individually adjusted lowest haematocrit level and the minimisation of intra-operative blood loss by the application of optimal surgical techniques are among the most essential strategies to reduce or even avoid allogeneic blood transfusions
Actively reducing the number of patients requiring blood transfusion after cardiac surgery is a process which involves actors at every stage of hospitalization and, as such, requires more than the simple minimization of surgical invasiveness once held to be a key factor
] each detail in the treatment of these patients is crucial. Starting preoperatively by raising the level of hemoglobin by use of EPO and iron therapy, eliminating any hemodilution, to proper operative field drainage to reduce the incidence of hematomas related to various invasive maneuvers over the course of hospitalization, keeping the hemoglobin value under 15.5 to avoid associated complications with high hematocrit value
]. The most recent example of this comprehensive multimodality approach is the mini-cardiopulmonary bypass system that we have been using for the last three years, combined with retro-priming and a cell saver
] which maintains a constant hemoglobin level, often low in cardiac patients. Volume expansion in these patients is associated with a real risk of hemodilution and active participation of the anesthetist is essential to avoid additional iatrogenic vasoplegia, which is greatly facilitated by concentration-aimed ultra-fast-track anesthesia protocols
]. However, multifactorial progress has been made since the series published by Cooley
], which has recently been confirmed by Jassar
]. In contrast with teams who use systemic hypothermia or crystalloid cardioplegia, normothermic surgery provides the same rheological results without hemodilution. The complete, unmodified Cornell University protocol has therefore been systematically employed
]. This attitude is all the more important in that preoperative hemodilution induced by deferred auto-transfusion cannot be performed upon Jehovah’s Witnesses who refuse any interruption of the blood circulation for religious reasons.
3) Legal and Ethical Aspects of Non Transfusion
It has been suggested that patients who receive transfusions following cardiac surgery had twice the long-term mortality risk than patients who did not receive transfusions
]. The administration of blood transfusions therefore appears to be an independent factor of death. If these results attain factual status, then for both medical and legal reasons, all efforts must be made to avoid recourse to blood transfusion not only amongst Jehovah’s Witnesses, but in all patients. A review of the existing literature on methods of blood transfusion indicates not only a discordance in practice amongst medical teams, but even amongst members of the same team: yet the morbidity-mortality rates are ubiquitous in the first 30 postoperative days
]. Therefore, it appears desirable to replace these highly unsystematic methods of transfusion with a protocol of blood conservation which involves all members of the caring team. To undertake such a protocol is both medically justified and feasible.
The restraining factor in the implementation of such a protocol is cost, as the proposed blood conservation protocol relies upon two medications: aprotinin and EPO
]. Hence, the cost-benefit analysis depends primarily on the price of EPO. It must be remembered that EPO takes effect with some delay, its effectiveness is uncertain and, at present, its cost is prohibitively expensive. The extent of the delay in its effectiveness depends on the degree of preoperative anaemia. In France, EPO is used in the treatment of anaemia linked to renal failure, and occasionally preoperatively in anaemic patients.
The decision not to administer blood transfusions presents the medical team with an ethical dilemma as, in extreme circumstances, the members may be confronted with a situation in which a patient who could otherwise been saved must be left to die in order for their choice of non transfusion to be respected. Not only does this present an ethical dilemma for doctors but, in France, also presents a potential legal dilemma, since the preoperative consent form signed by the patient does not hold value, in light of the principal of “non-assistance to a personin danger
”, which is in direct opposition to the voiced desires of the patient. It is thus held to be of the utmost importance to reduce all possible risks related to non transfusion
] in order to prevent the possibility of extreme situations in which such ethical and legal dilemmas may arise. We succeeded in this aspect in all cases except four who were conscious and repeatedly refused transfusion despite the propositions of the attending medical professionals. These preoperative exclusions account for the better results obtained in group B compared with the outcomes attained in group A. This rigorous selection process allowed us to propose standard techniques of treatment to all our patients, such as mitral valve repair and total arterial revascularization, a technique which enhances blood conservation. Redo operations did not present a problem as we systematically applied the technique described by O’Bryan which has not resulted in a single major cardiac event in over 300 re-operations
]. Nevertheless, these operative redos remain risky endeavors which must be evaluated on a case by case basis.