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Response to Bamgbade OA letter
- Jose Otavio C. Auler Jr., DA Otsuki, DT Fantoni, CB Margarido, CK Marumo, T Intelizano, CA Pasqualucci (13 March 2007)
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Hydroxyethyl starch is superior to lactated Ringer as replacement fluid in acute normovolaemic haemo
- Olumuyiwa A Bamgbade, Sean J McAfee; Raja Jayaram (16 February 2007)
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Jose Otavio C. Auler Jr. , DA Otsuki, DT Fantoni, CB Margarido, CK Marumo, T Intelizano, CA Pasqualucci
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Dear Editor Bamgbade and colleagues' letter about our article (1)was of great interest to us as it gave us the opportunity to clarify some of the points raised by them. They commented that acute normovolemic hemodilution (ANH) produces a strong impact on the work of the heart, which was more noticeable in the experimental group. They argue this increase in myocatrdial work would be detrimental in patients with ischaemic heart disease, or those who already have an increased load on myocardium as during surgery on abdominal aorta. Supposedly, in the myocardium, hemodilution-induced lowering of blood viscosity facilitates blood flow through stenotic and collateral vessels, thereby equalizing the reduced blood oxygen-carrying capacity (2). To our knowledge, there is no clinical data specifically evaluating the impact of ANH comparing crystalloids versus synthetic colloids in patients with coronary artery disease undergoing anaesthesia. Indeed , although ischemic cardiac dysfunction has not been detected during moderate normovolemic hemodilution (Hb lowered to 90 g/L or hematocrit levels of 28%; higher levels than experimental settings)even in anaesthetized patients with coronary artery disease, clinical outcome benefits or negative events have not been methodically investigated in high-risk patients for myocardial ischemia (3). Sporadic reports of myocardial ischemia have been credited to extremely low hemoglobin levels, concomitant hypovolemia and reflex tachycardia in awake or in postoperative patients (4,5). In patients with severe aortic stenosis where, theoretically, ANH would be cautiously employed, Licker and colleagues showed that moderate ANH to a haemoglobin value of 9 g/dl was safely performed in patients with critical aortic stenosis, and it preserved LV function. Lowering of blood viscosity was associated with an increased cardiac output that was mainly related to enhanced venous return and higher preload indices. However, this adaptive haemodynamic response is limited and the safety margin for ANH is reduced because of acceleration of blood flow and dissipation of kinetic energy at the obstructed valve (6). The same group demonstrated that moderate ANH prior to on-pump CABG confers additional myocardial protection beyond that provided by blood cardioplegia and anesthetic preconditioning, as expressed by lower release of biomarkers of myocardial injury, lesser requirements for inotropic support, as well as fewer patients presenting with arrhythmia or conduction disorders after weaning from CPB (7). Side effects of HES on the coagulation system have been addressed as a potential negative effect. These effects on hemostasis are determined by the in vivo degradation of a particular HES preparation. High-molecular-weight HES and medium-molecular-weight HES with a high molar substitution are classified as slowly degradable HES; medium- molecular-weight HES with a low molar substitution (200/0.5) and low- molecular-weight HES (130/0.4) are classified as rapidly degradable HES (8). A metaanalysis involving 16 trials and 653 randomized patients showed a significant higher postoperative bleeding in cardiopulmonary bypass patients exposed to slowly degradable HES than in those exposed to albumin (9). In contrast to slowly degradable HES, patients receiving rapidly degradable HES were not different with respect to blood loss and transfusion necessities after cardiac, major abdominal, and orthopedic surgery when compared with patients receiving gelatin or albumin (10, 11, 12). Haisch and colleagues deduced that administration of moderate doses of the new HES 130/0.4 preparation in patients undergoing major abdominal surgery results in similar coagulation alterations as those after using an established gelatin-based volume-replacement regimen (13). In conclusion, these rapidly degradable HES solutions have minimal influence, if any, on hemostasis (8). References: 1. Otsuki DA, Fantoni DT, Margarido CB, Marumo CK, Intelizano T, Pasqualucci CA, Auler JOC. Hydroxyethyl starch is superior to lactated Ringer as a replacement fluid in a pig model of acute normovolaemic haemodilution. British Journal of Anaesthesia 2007; 98:29-37. 2. Pries AR, Secomb TW. Rheology of the microcirculation. Clin Hemorheol Microcirc 2003; 29:143–148. 3. Spahn DR, Schmid ER, Seifert B, Pasch T. Hemodilution tolerance in patients with coronary artery disease who are receiving chronic - adrenergic blocker therapy. Anesth Analg 1996; 82:687–694. 4. Carvalho B, Ridler BM, Thompson JF, Telford RJ. Myocardial ischaemia precipitated by acute normovolaemic haemodilution. Transfus Med 2003; 13:165–168. 5. Leung JM, Weiskopf RB, Feiner J, Hopf HW, Kelley S, Viele M, Lieberman J, Watson J, Noorani M, Pastor D, Yeap H, Ho R, Toy P. Electrocardiographic ST-segment changes during acute, severe isovolemic hemodilution in humans. Anesthesiology 2000; 93:1004–1010. 6. Licker M, Ellenberger C, Murith N, Tassaux D, Sierra J, Diaper J, Morel DR. Cardiovascular response to acute normovolaemic haemodilution in patients with severe aortic stenosis: assessment with tranoesophageal achocardiography. Anaesthesia 2004, 59:1170–1177. 7. Licker M, Ellenberger C, Sierra J, Kalangos A, Diaper J, Morel D. Cardioprotective effects of acute normovolemic hemodilution in patients undergoing coronary artery bypass surgery. Chest 2005; 128:838–847. 8. Kozek-Langenecker SA. Effects of hydroxyethyl starch solutions on hemostasis. Anesthesiology 2005; 103:654-60. 9. Wilkes MM, Navickis RJ, Sibbald WJ: Albumin versus hydroxyethyl starch in cardiopulmonary bypass surgery: A meta-analysis of postoperative bleeding. Ann Thorac Surg 2001; 72:527–37. 10. Kasper SM, Meinert P, Kampe S, Gorg C, Geisen C, Mehlhorn U, Diefenbach C: Large-dose hydroxyethyl starch 130/0.4 does not increase blood loss and transfusion requirements in coronary artery bypass surgery compared with hydroxyethyl starch 200/0.5 at recommended doses. Anesthesiology 2003; 99:42–7. 11. Huttner I, Boldt J, Haisch G, Suttner S, Kumle B, Schulz H: Influence of different colloids on molecular markers of haemostasis and platelet function in patients undergoing major abdominal surgery. Br J Anaesth 2000; 85:417–23. 12. Boldt J, Haisch G, Suttner S, Kumle B, Schellhaass A: Effects of a new modified, balanced hydroxyethyl starch preparation (Hextend) on measures of coagulation. Br J Anaesth 2002; 89:722–8. 13. Haisch G, Boldt J, Krebs C, Kumle B, Sutter S, Schulz A. The influence of intravascular volume therapy with a new hydroxyethyl starch preparation (6% HES 130/0.4) on coagulation in patients undergoing major abdominal surgery. Anesth Analg 2001; 92:565–71. Conflict of Interest:None declared |
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Olumuyiwa A Bamgbade, Consultant Anaesthetist Central Manchester University Hospital, Manchester, UK, Sean J McAfee; Raja Jayaram
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The article by Otsuki et al (1) comparing hydroxyethyl starch (HES) with lactated Ringer as replacement fluid during acute normovolaemic haemodilution (ANH) was very interesting. It provides more information regarding the debate on optimal replacement fluid in major haemorrhage or major surgery patients. This prospective, randomized, controlled animal study has a rigorous methodology, and involved extensive data collection of a large variety of physiological parameters. It also included pathologic evaluation of myocardial, liver and gastrointestinal tissue samples for post-infusion structural damage. The study reliably showed better haemodynamics, improved gastric intramucosal pH and less post- infusion myocardial tissue damage with HES administration, and this result appears valid. The study result supports that of previous studies which showed that HES volume replacement is better than crystalloid and other fluids in terms of haemodynamics and tissue oxygenation (2,3). Although the article by Otsuki et al (1) appears reliable, can this study be reproduced in the human population with or without tissue sample analysis? It is noteworthy that cardiac index (CI), stroke volume index (SVI) and left ventricular stroke work index (LVSWI) increased significantly in the HES group compared to the lactated Ringer group. Could this increased myocardial work have a negative impact on myocardial outcome in patients with ischaemic heart disease or other forms of heart disease, who may require ANH; such as elective aortic aneurysm surgery patients? It would be interesting to analyze the coagulation parameters of the study sample, to check for coagulopathy, a known adverse effect of HES (4). Could the volumes of HES used for ANH in the study by Otsuki et al (1) lead to increased coagulopathy with consequent haemorrhage and a need for blood product transfusion? References: 1. Otsuki DA, Fantoni DT, Margarido CB, et al. Hydroxyethyl starch is superior to lactated Ringer as a replacement fluid in a pig model of acute normovolaemic haemodilution. Br J Anaesth 2006; 98: 29-37. 2. Guo X, Xu Z, Ren H, et al. Effect of volume replacement with hydroxyethyl starch solution on splanchnic oxygenation in patients undergoing cytoreductive surgery for ovarian cancer. Chinese Med J 2003; 116: 996-1000. 3. Lang K, Boldt J, Suttner S, Haisch G. Colloids versus crystalloids and tissue oxygen tension in patients undergoing major abdominal surgery. Anesth Analg 2001; 93: 405-9. 4. Egli GA, Zollinger A, Seifert B, et al. Effect of progressive haemodilution with hydroxyethyl starch, gelatin and albumin on blood coagulation. Br J Anaesth 1997; 78:684-689. Conflict of Interest:None declared |
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