- Email: [email protected]
The effect of preoperative tranexamic acid on blood loss after cardiac operations in children
LITERATURE REVIEW
966
Korn RL, Fisher CA, Livingston ER, et al: The effects of Carmeda Bioactive Surface on human blood components during simulated extracorporeal circulation. J Thorac Cardiovasc Surg 111:1073-1084, 1996
Schueppert MT, K r e s o w i k T F , C o r r y D C , et al: Selection of patients for cardiac evaluation before peripheral vascular operations. J Vasc Surg 23:802809, 1996
The Carmeda Bioactlve Surface (Medtromcs Cardiopulmonary, Anaheim, CA) was studied in an in vitro model of extracorporeal circulation at standard dose heparin (5 U/mL) and reduced dose heparin (1 U/mL). During reorculation of human blood, platelet counts were preserved at both heparln doses compared with control circuits Plasma levels of platelet factor 4 and betathromboglobuhn were sigmficantly reduced in the Carmeda circuits. Leukocyte depletton and release of elastase at both heparin concentrations were reduced. C3a generation was also decreased The Carmeda Surface did not exhibit anticoagulant efficacy, as fibrinopeptide A generation was not reduced m the Carmeda circuit at the lower heparin dose
In a 3-year period, 394 patients underwent routine preoperative dipyridamole thallium sclntlgraphy (DTS) and radxonuehde ventrleulography before elective vascular surgery All patients with reversible DTS defects underwent coronary arterlography DTS results were normal in 37% of patients and showed a fixed defect in 19% and a reversible defect in 44%. Of note, the rates of reversible defects were identical in patients with and without a history of angina or myocardial infarction. Coronary arteriography was performed m 136 patients, and three-vessel or left main disease was found m 49 patients, leading to coronary revascularizatIon m 30 The protocol was associated with considerable financial and morbid cost; there were two deaths and nine major complications as a result of cardiac evaluation and treatment. Potential benefits of the screening protocol included detection of coronary disease m asymptomatlc patients and selection of perloperatIve monitoring and drug management guided by the screening results. The authors acknowledge that given the cost of the screening studies and high incidence of coronary disease m vascular patients, ~t may be more efficacious to treat all patients as ff they had significant coronary artery disease.
Katsaros D, Petricevic M, Snow N J, et ah Tranexamic acid reduces postbypass blood use: A doubleblinded, prospective, randomized study of 210 patients. Ann Thorac Surg 61:1131-1135, 1996 A 48% reduction in 24-hour blood drainage (474 v 906 mL) was achieved by administration of tranexamic acid, 10 g, before incision in patients (n = 104) undergoing primary coronary revascularlzatlon compared to controls (n = 106). Thirteen of 104 treated patients received blood products versus 33 ol 106 controls Utihzation of red blood cells, plasma, and platelets was reduced by tranexamlc acid treatment The incidence of thrombotic complications did not differ between groups
Zonis Z, Seear M, Reichert C, et al: The effect of preoperative tranexamic acid on blood loss after cardiac operations in children. J Thorac Cardiovasc Surg 111:982-987, 1996 Tranexamlc acid, 50 mg/kg, IV, or placebo, was administered to 88 children (mean age 57 months) undergoing cardiac surgery, before skin incision Postoperative blood loss In the first 6 hours was significantly reduced by tranexamic acid treatment (11 mL/kg v 27 mL/kg) in the patient group with cyanotic heart disease Significantly fewer blood products were administered to the treated cyanotic patient group, although criteria for blood product admimstrataon by the blinded intensivlsts are not described. The antifibrlnolytlc had no effect m acyanotic children or those undergoing reoperatIon
Kurz A, Sessler DI, Lenhardt R, et ah Perioperative normothermia to reduce the incidence of surgical wound infection and shorten hospitalization. N Engl J Med 334:1209-1215, 1996 In 200 patients undergoing colorectal surgery randomly assigned to routine or additional thermal care, the final intraoperatwe core temperatures were 34.7 versus 36 6°C. Surgical wound infections occurred m 19% of the hypothermlc group and in 6% of the patients in whom normothermla was maintained Duration of hospitalization was prolonged by 2 6 days in the hypothermlc group Immune function Is impaired by hypothermia; reduced tissue oxygen tensions caused by thermoregulatory vasoconstriction impair oxidative healing by neutrophils and wound healing by reducing collagen deposition.
REVIEW ARTICLES
Fleisher LA, Eagle KA: Screening for cardiac disease in patients having noncardiac surgery. Ann Intern Med 124:767-772, 1996 Bodenheimer MM: Noncardiac surgery in the cardiac patient: What is the question? Ann Intern Med 124:763-766, 1996 Fleisher and Eagle reviewed the rationale behind preoperatwe cardiac screening, suggesting that high-risk patients can be identified for whom Intensive perloperatwe monitoring, administration of beta-adrenerglc antagomsts, or coronary revascularization are appropriate. The value of routine versus selective nomnvaslve cardiac testing is discussed FleIsher and Eagle conclude that nonlnvaslve cardiovascular testing for coronary disease is best reserved for selected patients at moderate clinical risk, in other patient populations, the tests lose their predlctwe value because of a high incidence of false-negative and false-positive results Bodenhelmer dlstingmshes two patient groups based on mechamsms of postoperative myocardial Infarction Adverse cardiac events in the first group result from postoperative stress and excess eatecholamine levels resulting in "demand ~sehemla "' Improved clinical outcomes are more likely to result from preventing excessive myocardial oxygen demand perioperatlvely m this patient group than from performance of screening tests On the other hand, in patients with a clinical syndrome consistent with exlstmg plaque rupture such as unstable angina leading to "supply Ischemla," noncardlac surgery should be deferred and the patient's cardiac status evaluated and treated. Because few data support the use of prophylactic coronary revascularIzatIon to improve penoperatlve outcome from noncardlac surgery, Bodenheimer suggests that physicians not ponder the question of which patient at risk for coronary artery disease needs further evaluation before noncardlac surgery. The more appropriate question is, "Why do patients experience adverse events and how might these be prevented9''
966
Korn RL, Fisher CA, Livingston ER, et al: The effects of Carmeda Bioactive Surface on human blood components during simulated extracorporeal circulation. J Thorac Cardiovasc Surg 111:1073-1084, 1996
Schueppert MT, K r e s o w i k T F , C o r r y D C , et al: Selection of patients for cardiac evaluation before peripheral vascular operations. J Vasc Surg 23:802809, 1996
The Carmeda Bioactlve Surface (Medtromcs Cardiopulmonary, Anaheim, CA) was studied in an in vitro model of extracorporeal circulation at standard dose heparin (5 U/mL) and reduced dose heparin (1 U/mL). During reorculation of human blood, platelet counts were preserved at both heparln doses compared with control circuits Plasma levels of platelet factor 4 and betathromboglobuhn were sigmficantly reduced in the Carmeda circuits. Leukocyte depletton and release of elastase at both heparin concentrations were reduced. C3a generation was also decreased The Carmeda Surface did not exhibit anticoagulant efficacy, as fibrinopeptide A generation was not reduced m the Carmeda circuit at the lower heparin dose
In a 3-year period, 394 patients underwent routine preoperative dipyridamole thallium sclntlgraphy (DTS) and radxonuehde ventrleulography before elective vascular surgery All patients with reversible DTS defects underwent coronary arterlography DTS results were normal in 37% of patients and showed a fixed defect in 19% and a reversible defect in 44%. Of note, the rates of reversible defects were identical in patients with and without a history of angina or myocardial infarction. Coronary arteriography was performed m 136 patients, and three-vessel or left main disease was found m 49 patients, leading to coronary revascularizatIon m 30 The protocol was associated with considerable financial and morbid cost; there were two deaths and nine major complications as a result of cardiac evaluation and treatment. Potential benefits of the screening protocol included detection of coronary disease m asymptomatlc patients and selection of perloperatIve monitoring and drug management guided by the screening results. The authors acknowledge that given the cost of the screening studies and high incidence of coronary disease m vascular patients, ~t may be more efficacious to treat all patients as ff they had significant coronary artery disease.
Katsaros D, Petricevic M, Snow N J, et ah Tranexamic acid reduces postbypass blood use: A doubleblinded, prospective, randomized study of 210 patients. Ann Thorac Surg 61:1131-1135, 1996 A 48% reduction in 24-hour blood drainage (474 v 906 mL) was achieved by administration of tranexamic acid, 10 g, before incision in patients (n = 104) undergoing primary coronary revascularlzatlon compared to controls (n = 106). Thirteen of 104 treated patients received blood products versus 33 ol 106 controls Utihzation of red blood cells, plasma, and platelets was reduced by tranexamlc acid treatment The incidence of thrombotic complications did not differ between groups
Zonis Z, Seear M, Reichert C, et al: The effect of preoperative tranexamic acid on blood loss after cardiac operations in children. J Thorac Cardiovasc Surg 111:982-987, 1996 Tranexamlc acid, 50 mg/kg, IV, or placebo, was administered to 88 children (mean age 57 months) undergoing cardiac surgery, before skin incision Postoperative blood loss In the first 6 hours was significantly reduced by tranexamic acid treatment (11 mL/kg v 27 mL/kg) in the patient group with cyanotic heart disease Significantly fewer blood products were administered to the treated cyanotic patient group, although criteria for blood product admimstrataon by the blinded intensivlsts are not described. The antifibrlnolytlc had no effect m acyanotic children or those undergoing reoperatIon
Kurz A, Sessler DI, Lenhardt R, et ah Perioperative normothermia to reduce the incidence of surgical wound infection and shorten hospitalization. N Engl J Med 334:1209-1215, 1996 In 200 patients undergoing colorectal surgery randomly assigned to routine or additional thermal care, the final intraoperatwe core temperatures were 34.7 versus 36 6°C. Surgical wound infections occurred m 19% of the hypothermlc group and in 6% of the patients in whom normothermla was maintained Duration of hospitalization was prolonged by 2 6 days in the hypothermlc group Immune function Is impaired by hypothermia; reduced tissue oxygen tensions caused by thermoregulatory vasoconstriction impair oxidative healing by neutrophils and wound healing by reducing collagen deposition.
REVIEW ARTICLES
Fleisher LA, Eagle KA: Screening for cardiac disease in patients having noncardiac surgery. Ann Intern Med 124:767-772, 1996 Bodenheimer MM: Noncardiac surgery in the cardiac patient: What is the question? Ann Intern Med 124:763-766, 1996 Fleisher and Eagle reviewed the rationale behind preoperatwe cardiac screening, suggesting that high-risk patients can be identified for whom Intensive perloperatwe monitoring, administration of beta-adrenerglc antagomsts, or coronary revascularization are appropriate. The value of routine versus selective nomnvaslve cardiac testing is discussed FleIsher and Eagle conclude that nonlnvaslve cardiovascular testing for coronary disease is best reserved for selected patients at moderate clinical risk, in other patient populations, the tests lose their predlctwe value because of a high incidence of false-negative and false-positive results Bodenhelmer dlstingmshes two patient groups based on mechamsms of postoperative myocardial Infarction Adverse cardiac events in the first group result from postoperative stress and excess eatecholamine levels resulting in "demand ~sehemla "' Improved clinical outcomes are more likely to result from preventing excessive myocardial oxygen demand perioperatlvely m this patient group than from performance of screening tests On the other hand, in patients with a clinical syndrome consistent with exlstmg plaque rupture such as unstable angina leading to "supply Ischemla," noncardlac surgery should be deferred and the patient's cardiac status evaluated and treated. Because few data support the use of prophylactic coronary revascularIzatIon to improve penoperatlve outcome from noncardlac surgery, Bodenheimer suggests that physicians not ponder the question of which patient at risk for coronary artery disease needs further evaluation before noncardlac surgery. The more appropriate question is, "Why do patients experience adverse events and how might these be prevented9''