Received Date: November 16, 2012; Accepted Date: November 17, 2012; Published Date: November 27, 2012
Citation: Hadler R (2012) What (if any) Special Factors Should Come into Preoperative Assessment of Patients for Bloodless Surgery? J Anesthe Clinic Res 4:271. doi: 10.4172/2155-6148.1000271
Copyright: © 2012 Hadler R. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Animal data shows myocardial ischemia (demonstrated by ST changes on EKG) at a hemoglobin concentration of <5. Studies of young healthy adults showed cognitive and cardiac changes at hemodilution levels resulting in hemoglobin of 5-7 g/dL. (Carson) In consenting patients with minimal comorbidities, a hemoglobin level of <7 mg/dL is commonly viewed as a reasonable threshold for transfusion. Patients who refuse transfusion, whether for medical or religious reasons, present unique management challenges in the setting of intraoperative blood loss. Studies of such patients undergoing surgery under bloodless protocols demonstrated increased postoperative morbidity and mortality at hemoglobin concentrations <8.0 g/dL. .
“Bloodless surgery” is a relatively new discipline within perioperative care with the intent of safely avoiding transfusion while maintaining acceptable patient outcomes. The field of bloodless surgery emerged in the 1960s, when cardiac surgeons in Texas developed a ‘bloodless prime’ for cardiopulmonary bypass machines, enabling major cardiac surgery in patients excluded from such surgeries for reasons related to transfusion . Although initially marginalized, the practice took increasing root with the safe blood scares of the 1980s and with subsequent discoveries of long term sequellae of blood storage in the 1990s and 2000s. The term “bloodless surgery” now describes a multimodal approach involving surgeons, anesthesiologists, hematologists, cardiologists, and numerous other practitioners, and dictates a long-term approach deeply rooted in preoperative management to nontransfuseable patients facing major surgery.
As for most patients facing major surgery, preoperative considerations for bloodless patients are directed towards assessing and optimizing preoperative functionality. The heart and lungs feature prominently among organ systems on the preoperative history and physical; any existing cardiopulmonary and metabolic derangements should be optimized preoperatively with initiation/ continuation of beta blockers in cardiac patients, achievement of glucose control in diabetic patients, treatment of active infections and bronchodilators in patients with COPD .
It is also crucial to identify risk factors for surgical bleeding, including platelet dysfunction, kidney and liver disease, and to examine fully home medications and herbal supplements for agents potentially increasing bleeding risk (including obvious choices such as aspirin, anticoagulants and NSAIDS but also beta-lactams, some psychotropic drugs and many herbal supplements) Any history of bleeding disorders or anemia should be analyzed. Appropriate labs include a CBC with differential, reticulocyte count, B12/ folate levels, coagulation factors with additional studies of platelet function and specific clotting factors as needed.
Preoperative planning should be multidisciplinary, and focus on minimizing intraoperative blood loss while maximizing preoperative hemoglobin levels. Measures to promote hematopoiesis include supplementation of iron, vitamin C and B12 and folic acid as well as exogenous epoeitin and androgen therapy, granulocyte colonystimulating factors, steroids and interleukin-11. EPO treatments combined with IV iron supplementation can magnify red-blood cell production fourfold . One technique for maximizing red blood cell mass preoperatively suggests Epogen doses at 600U/kg weekly for 3 weeks prior to surgery or 300U/kg daily for 10 days prior and 4 days after surgery. In emergency situations, the patient should receive 300U/kg daily for 2 weeks postoperatively. (Carson) Clotting factor deficiencies should be corrected with vitamin K and recombinant clotting factors. Specific considerations for the anesthesiologist include safe alternatives to general anesthesia as well as means of maintaining normothermia and normovolemia (without excessive hemodilution) intraoperatively. Additionally, some patients may be candidates for autologous blood donation. Drawbacks to preoperative autologous donation include increased likelihood of transfusion and, as autologous blood is often transfused as whole blood, increased risk of circulatory overload .
The extent to which this degree of preoperative management has been implemented is debatable. A 1997 survey sent to 1,000 U.S. hospitals revealed relatively low use of preoperative pharmaceutical therapy to improve blood counts (EPO was used routinely in 11% of responding hospitals, and occasionally in 9%) (Shander); no follow-up studies of utilization are available at this point. As bloodless surgery becomes increasingly mainstream, though, we can aspire to see this level of coordinated patient care take root and perhaps influence preoperative care more broadly.