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Acute perioperative normovolaemic haemodilution in major maxillofacial surgery
Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
Acute perioperative normovolaemic haemodilution in major maxillofacial surgery I.R. Parkin a , G.A. Chiu a,∗ , P.A. Schwarz b , S.C. Hodder a a b
Department of Oral & Maxillofacial Surgery, Morriston Hospital, Swansea, South Wales, SA6 6NL, UK Department of Anaesthesia, Morriston Hospital, Swansea, South Wales, SA6 6NL, UK
Accepted 1 January 2008 Available online 5 March 2008
Abstract Extensive blood loss can occur when patients have major operations for head and neck neoplasia. The risks and costs of allogeneic blood transfusion have been well documented. Acute perioperative normovolaemic haemodilution (APNH) is a method of saving blood and autologous transfusion. The purpose of this study was to compare a group of patients having major head and neck operations who had APNH, with a historical group, to assess the need for allogeneic transfusion. Of the 21 patients who had APNH only one patient required allogeneic blood. In the historical group of 24 patients, 15 patients had required allogeneic blood (p = 0.0001). APNH is an economic, safe and practical way of saving blood. © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Acute perioperative normovolaemic haemodilution; Maxillofacial Surgery
Acute perioperative normovolaemic haemodilution (APNH) is the removal of blood from a patient immediately before operation and simultaneous replacement with an appropriate volume of crystalloid or colloid, to maintain the circulating volume. This provides the blood that may be necessary for the autologous transfusion later.1,2 This method of saving blood may also be accepted by Jehovah’s Witnesses.3 In the UK, it has been emphasised that all National Health Service Trusts should review and explore the use of effective alternatives to donor allogeneic blood and the appropriate use of autologous transfusion.4 Varney et al. in 20015 showed that the annual cost of blood transfusion in the UK increased by 256% compared with 1994, to £898 million. During this time the number of total blood products issued also increased by 17%, with an estimated 1.7 million patients being given transfusions. The
number of donations of whole blood also increased by 2% to 2.8 million. Not only is it expensive, but blood transfusion has serious risks. Patients with neoplasia of the head and neck undergo major operations that may involve dissection of lymph glands in the neck, resection of the tumour, and a reconstructive procedure that may require transfer of a free flap. These patients routinely have their blood cross matched, as these procedures often involve large blood loss and require the replacement of fluid, both crystalloid and colloid. Our aim was to evaluate the use of APNH and autologous blood transfusion in patients having major head and neck resections and to see if there was a reduced need for allogeneic blood transfusion.
Methods ∗
Corresponding author. Tel.: +44 0780 304 6387. E-mail address: [email protected] (G.A. Chiu).
The local research Ethics Committee approved the study. Informed written consent was sought from patients. From
0266-4356/$ – see front matter © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2008.01.002
388
I.R. Parkin et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
March 2003-04, consecutive patients who were to have major maxillofacial resections for neoplasia to the head and neck had APNH. This consisted of resection of the carcinoma in the head and neck region with neck dissection, with or without reconstruction, done by one specialist head and neck surgical team. Patients with preoperative anaemia (less than 110 g/L) and those with congestive cardiac failure did not have APNH. Patients who were unwilling or unable to give informed consent were also excluded. Data were collected prospectively. After patients had been anaesthetised and an arterial line inserted together with a femoral central line and temperature probe, APNH was done by taking two units through the femoral central line. The bags were labelled with the patient’s name, date of birth, and hospital number, and stayed with the patient in the operating theatre. Simultaneously, a crystalloid or colloid infusion was given. The amount was titrated to maintain a constant heart rate, monitored on electrocardiography (ECG) tracing and arterial pressure. The stored blood was kept in theatre for up to six hours during the operation. According to the blood bank there was no need to store the blood in a refrigerator. Doing so would mean having to move the blood away from the patient leading to possible errors in giving the right blood to the right patient. APNH was done simultaneously to the other procedures, including catheterisation of the urinary bladder, positioning of the patient on the table, cleaning and preparation of the surgical field, and the beginning of the tracheostomy. Intraoperative fluid losses were replaced with crystalloid or colloid infusions to maintain central venous pressure. Arterial blood gas analysis and measurement of the haemoglobin concentration were done after the tumour had been resected and the neck dissected; this is the time during which most blood loss is expected to occur. Blood loss was measured by weighing swabs, and adding the amount collected in the suction drain. Towards the end of the operation, before the patient left the operating theatre to go to the intensive care unit (ICU), all patients were given the autologous transfusion. In the ICU post operative haemoglobin concentrations were measured. These results were then compared with those of a historical group of consecutive patients who had similar maxillofacial procedures from March 2002 to 2003. All procedures were carried out by the same surgical and anaesthetic consultants with identical surgical and anaesthetic techniques. Any patient, in either group, with a haemoglobin less than 80 g/L was transfused with allogeneic blood, the aim being to bring the concentration over 100 g/L. Student’s t test was used assess the significance of difference between the two groups.
Results Twenty one patients were eligible for APNH. The two groups were similar (Table 1). Only one person from the study group
Table 1 Comparability of the two groups
Sex: M/F Age (years) at operation (range) Patients with coagulopathy: Alcoholic liver disease Taking Warfarin
Historical (n = 24)
Study (n = 21)
18/6 61 (38–95) 0
17/ 4 62 (46–78) 3 1 2
had 1 unit allogeneic blood transfused. Fifteen patients in the historical group required 2-4 units of allogeneic blood. Overall, this was a mean of 2 units (range 0–4 units) (p = 0.0001). Mean (SD) blood loss in the study group was 975 (230) ml, compared with 829 (205) ml in the historical group, (p = 0.03).
Discussion There was no significant difference in the incidence of surgical complications between the groups, and no significant anaesthetic or cardiovascular events were seen in either group. The patient in the study group who had allogeneic blood could have avoided transfusion as there was a failure to adhere to the study protocol and blood was given before the concentration of 80 g/L was reached. A possible reason for the apparent increase in blood loss in the study group was that three patients had pre-existing coagulopathies, although this blood loss was not detrimental to their outcome. We know of one other comprehensive study that investigated the effects of APNH and autologous transfusion in patients with head and neck cancer. Habler et al.6 studied 124 patients having major maxillofacial surgery (68% oncology and 32% for deformities). They showed that this technique avoided the used of allogeneic blood transfusion in 89% of the patients. They found it to be safe, effective, economic and not time consuming. Our study also shows that APNH and autologous blood transfusion have no adverse effects and reduce the need for allogeneic transfusion. Not only does this save money (Table 2) but it also spares the patients from the known risks of allogeneic transfusion. These include viral hepTable 2 Cost benefits of acute perioperative normovolaemic haemodilution. Costs were obtained from Swansea NHS Trust in 2006 Item
Cost (£ sterling)
1 unit of cross matched of leucocyte depleted blood Two collection bags for haemodilution Savings made per patient given a transfusion assuming a mean allogeneic transfusion requirement of: 2 units 4 units Cost of episode of transfusion incompatibility
165 12
318 618 Not known
I.R. Parkin et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
atitis, human immunodeficiency virus (HIV), and variant Creutzfeldt-Jakob disease (vCJD). Head and neck operations are often associated with serious blood loss;7–9 transfusions are reportedly required in 14% to 80% of patients undergoing resections for head and neck cancer. A reason for such a wide range is perhaps the “trigger” haemoglobin concentration that indicates a transfusion is necessary and the type of operation done. Bilateral radical neck dissections with free flaps are more likely to have more blood loss than unilateral functional neck dissection.7 On a physiological basis, with each millilitre of blood lost during the operation, the dilutional effects of APNH will reduce the packed cell volume, so loss of red blood cell mass will be lower. A further reason for avoiding allogeneic blood transfusion in patients with cancer is its reported immunosuppressive effects. These were first described after transplants in the 1970s.10 The relation between allogeneic transfusion and increase in recurrent colorectal, lung, breast and renal cancer has been reported since the 1980s. Specific to patients with head and neck disease there has been a small number of retrospective studies11,12 that compared recurrence rates of head and neck cancer with those having allogeneic blood transfusion. The results have been conflicting. The main difficulty in identifying that allogeneic blood transfusion may be associated with recurrence is the number of variables present that can account for recurrence. Szakmany et al.12 & Tangiguchi et al.13 have suggested that allogeneic blood transfusion of 3 or more units might confer a worse prognosis on patients having operations for head and neck cancer. They reported that a possible underlying cause is dose related immunosuppression. A known advantage of APNH patients with head and neck cancer having free flap transfers is the effect of iatrogenic anaemia and subsequently lowered viscosity on survival of the free flap. Earle et al.14 first reported that reduced blood viscosity resulted in improvement in survival of a skin flap. They hypothesised that flow in the flap is inversely associated with blood viscosity. As haemoglobin is the main component of blood, which governs viscosity; so low haemoglobin concentrations indicate low blood viscosity which improves survival of the flap. Animal studies15–17 that studied the effect of haemodilution on the microcirculation and survival of the flap showed that an anaemic state is an effective method of improving survival. Qiao et al.18 reported a 93.3% flap survival rate of 30 free flaps in patients who had APNH and autologous blood transfusion. Other methods that help to reduce blood loss include meticulous surgical technique and good communication with the anaesthetist. Controlled hypotension is indicated as a means of reducing blood loss in maxillofacial procedures.19 This is a reached with a combination of anaesthetic agents and positioning of the patient. In this unit, the patient is tilted 300 head up, and the operating table broken with the legs raised to heart level. Advances that have helped to reduce intraoperative blood loss are the introduction of the ultrasonic scalpel20
389
and tissue fibrin sealants. A Cochrane review into the use of fibrin sealants has shown they are efficacious in reducing both postoperative blood loss and the need for postoperative transfusion.21 Allogeneic transfusion should therefore be avoided if possible.
References 1. Boulton FE, James V. Guidelines for policies on alternatives to allogeneic blood transfusion. I. Predeposit autologous blood donation and transfusion. British Committee for Standards in Haematology, Transfusion Task Force. Transfus Med 1997;5:354–65. 2. Napier JAF, Bruce M, Chapman JK, et al. Guidelines for autologous transfusion. II. Pre-operative haemodilution and cell salvage. British Committee for Standards in Haematology Blood Transfusion Task Force. Autologous Transfusion Working Party. Br J Anaesth 1997;78:768–71. 3. Code of practice for the surgical management of Jehovah’s Witnesses. London: Royal College of Surgeons of England, 2002. 4. Hill J, James V. Survey of autologous blood transfusion activity in England (2001). Guidelines for autologous transfusion. I. Pre-operative autologous donation. Transfus Med 2003;13:9–15. 5. Varney SJ, Guest JF. The annual cost of blood transfusion in the UK. Transfus Med 2003;13:205–18. 6. Habler O, Schwenzer K, Zimmer K, Prager M, Konig U, Oppenrieder A, et al. Effects of standardized acute normovolemic haemodilution on intraoperative allogeneic blood transfusion in patients undergoing major maxillofacial surgery. Int J Oral Maxillofac Surg 2004;33:467– 75. 7. Dulguerov P, Quinodoz D, Allal AS, Tassonyi E, Beris P. Blood transfusion requirements in otolaryngology-head and neck surgery. Acta Otolaryngol 1998;118:744–7. 8. Marchiori C, Fede A, Bassano M, Nieri A. Normovolemic hemodilution in head and neck surgery. Arch Otorhinolaryngol 1989;246:333– 5. 9. Krupp NL, Weinstein G, Chaliam A, Berlin JA, Wolf P, Weber R. Validation of a transfusion prediction model in head and neck cancer surgery. Arch Otolaryngol Head Neck Surg 2003;129:1297–302. 10. Opelz G, Sengar DPS, Mickey MR, Terasaki PI. Effect of blood transfusions on subsequent kidney transplants. Transplant Proc 1973;5:253– 9. 11. Moir MS, Samy RN, Hanasono MM, Terris DJ. Autologous and heterologous blood transfusion in head and neck cancer surgery. Arch Otolaryngol Head Neck Surg 1999;125:864–8. 12. Szakmany T, Dodd M, Dempsey GA, et al. The influence of allogeneic blood transfusion in patients having free flap primary surgery for oral and oropharyngeal squamous cell carcinoma. Br J Cancer 2006;94:647– 53. 13. Taniguchi Y, Okura M. Prognostic significance of perioperative blood transfusion in oral cavity squamous cell carcinoma. Head Neck 2003;5:931–6. 14. Earle AS, Fratianne RB, Nunez FD. The relationship of hematocrit levels to skin flap survival in the dog. Plast Reconstr Surg 1974;54:341– 4. 15. Velanovich V, Smith DJ, Robson MC, Heggers JP. The effect of hemoglobin and hematocrit levels on free flap survival. Am Surg 1988;54:659–63. 16. Desyatnikova S, Winslow C, Cohen JI, Wax MK. Effect of anemia on the fasciocutaenous flap survival in a rat model. Laryngoscope 2001;111:572–5. 17. Tuz M, Eroglu E, Dogru H, Delibas N, Tunc B, Uygur K. The effect of replacement fluids and normovolaemic haemodilution on the survival of dorsal skin flaps in rats. Clin Otolaryngol 2004;29:80– 3.
390
I.R. Parkin et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
18. Qiao Q, Zhou G, Chen GY, Ling YC, Zhang F, Bunke HJ. Application of hemodilution in microsurgical free flap transplantation. Microsurgery 1996;17:487–90. 19. Degoute C. Controlled hypotension: a guide to drug choice. Drugs 2007;67:1053–76.
20. Kos M, Engelke W. Advantages of a new technique of neck dissection using an ultrasonic scalpel. J Craniomaxillofac Surg 2007;35:10–4. 21. Carless PA, Henry DA, Anthony DM. Fibrin sealant use for minimising peri-operative allogeneic blood transfusion. Cochrane Database of Systematic Reviews 2003;(2). CD004171.
British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
Acute perioperative normovolaemic haemodilution in major maxillofacial surgery I.R. Parkin a , G.A. Chiu a,∗ , P.A. Schwarz b , S.C. Hodder a a b
Department of Oral & Maxillofacial Surgery, Morriston Hospital, Swansea, South Wales, SA6 6NL, UK Department of Anaesthesia, Morriston Hospital, Swansea, South Wales, SA6 6NL, UK
Accepted 1 January 2008 Available online 5 March 2008
Abstract Extensive blood loss can occur when patients have major operations for head and neck neoplasia. The risks and costs of allogeneic blood transfusion have been well documented. Acute perioperative normovolaemic haemodilution (APNH) is a method of saving blood and autologous transfusion. The purpose of this study was to compare a group of patients having major head and neck operations who had APNH, with a historical group, to assess the need for allogeneic transfusion. Of the 21 patients who had APNH only one patient required allogeneic blood. In the historical group of 24 patients, 15 patients had required allogeneic blood (p = 0.0001). APNH is an economic, safe and practical way of saving blood. © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Acute perioperative normovolaemic haemodilution; Maxillofacial Surgery
Acute perioperative normovolaemic haemodilution (APNH) is the removal of blood from a patient immediately before operation and simultaneous replacement with an appropriate volume of crystalloid or colloid, to maintain the circulating volume. This provides the blood that may be necessary for the autologous transfusion later.1,2 This method of saving blood may also be accepted by Jehovah’s Witnesses.3 In the UK, it has been emphasised that all National Health Service Trusts should review and explore the use of effective alternatives to donor allogeneic blood and the appropriate use of autologous transfusion.4 Varney et al. in 20015 showed that the annual cost of blood transfusion in the UK increased by 256% compared with 1994, to £898 million. During this time the number of total blood products issued also increased by 17%, with an estimated 1.7 million patients being given transfusions. The
number of donations of whole blood also increased by 2% to 2.8 million. Not only is it expensive, but blood transfusion has serious risks. Patients with neoplasia of the head and neck undergo major operations that may involve dissection of lymph glands in the neck, resection of the tumour, and a reconstructive procedure that may require transfer of a free flap. These patients routinely have their blood cross matched, as these procedures often involve large blood loss and require the replacement of fluid, both crystalloid and colloid. Our aim was to evaluate the use of APNH and autologous blood transfusion in patients having major head and neck resections and to see if there was a reduced need for allogeneic blood transfusion.
Methods ∗
Corresponding author. Tel.: +44 0780 304 6387. E-mail address: [email protected] (G.A. Chiu).
The local research Ethics Committee approved the study. Informed written consent was sought from patients. From
0266-4356/$ – see front matter © 2008 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2008.01.002
388
I.R. Parkin et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
March 2003-04, consecutive patients who were to have major maxillofacial resections for neoplasia to the head and neck had APNH. This consisted of resection of the carcinoma in the head and neck region with neck dissection, with or without reconstruction, done by one specialist head and neck surgical team. Patients with preoperative anaemia (less than 110 g/L) and those with congestive cardiac failure did not have APNH. Patients who were unwilling or unable to give informed consent were also excluded. Data were collected prospectively. After patients had been anaesthetised and an arterial line inserted together with a femoral central line and temperature probe, APNH was done by taking two units through the femoral central line. The bags were labelled with the patient’s name, date of birth, and hospital number, and stayed with the patient in the operating theatre. Simultaneously, a crystalloid or colloid infusion was given. The amount was titrated to maintain a constant heart rate, monitored on electrocardiography (ECG) tracing and arterial pressure. The stored blood was kept in theatre for up to six hours during the operation. According to the blood bank there was no need to store the blood in a refrigerator. Doing so would mean having to move the blood away from the patient leading to possible errors in giving the right blood to the right patient. APNH was done simultaneously to the other procedures, including catheterisation of the urinary bladder, positioning of the patient on the table, cleaning and preparation of the surgical field, and the beginning of the tracheostomy. Intraoperative fluid losses were replaced with crystalloid or colloid infusions to maintain central venous pressure. Arterial blood gas analysis and measurement of the haemoglobin concentration were done after the tumour had been resected and the neck dissected; this is the time during which most blood loss is expected to occur. Blood loss was measured by weighing swabs, and adding the amount collected in the suction drain. Towards the end of the operation, before the patient left the operating theatre to go to the intensive care unit (ICU), all patients were given the autologous transfusion. In the ICU post operative haemoglobin concentrations were measured. These results were then compared with those of a historical group of consecutive patients who had similar maxillofacial procedures from March 2002 to 2003. All procedures were carried out by the same surgical and anaesthetic consultants with identical surgical and anaesthetic techniques. Any patient, in either group, with a haemoglobin less than 80 g/L was transfused with allogeneic blood, the aim being to bring the concentration over 100 g/L. Student’s t test was used assess the significance of difference between the two groups.
Results Twenty one patients were eligible for APNH. The two groups were similar (Table 1). Only one person from the study group
Table 1 Comparability of the two groups
Sex: M/F Age (years) at operation (range) Patients with coagulopathy: Alcoholic liver disease Taking Warfarin
Historical (n = 24)
Study (n = 21)
18/6 61 (38–95) 0
17/ 4 62 (46–78) 3 1 2
had 1 unit allogeneic blood transfused. Fifteen patients in the historical group required 2-4 units of allogeneic blood. Overall, this was a mean of 2 units (range 0–4 units) (p = 0.0001). Mean (SD) blood loss in the study group was 975 (230) ml, compared with 829 (205) ml in the historical group, (p = 0.03).
Discussion There was no significant difference in the incidence of surgical complications between the groups, and no significant anaesthetic or cardiovascular events were seen in either group. The patient in the study group who had allogeneic blood could have avoided transfusion as there was a failure to adhere to the study protocol and blood was given before the concentration of 80 g/L was reached. A possible reason for the apparent increase in blood loss in the study group was that three patients had pre-existing coagulopathies, although this blood loss was not detrimental to their outcome. We know of one other comprehensive study that investigated the effects of APNH and autologous transfusion in patients with head and neck cancer. Habler et al.6 studied 124 patients having major maxillofacial surgery (68% oncology and 32% for deformities). They showed that this technique avoided the used of allogeneic blood transfusion in 89% of the patients. They found it to be safe, effective, economic and not time consuming. Our study also shows that APNH and autologous blood transfusion have no adverse effects and reduce the need for allogeneic transfusion. Not only does this save money (Table 2) but it also spares the patients from the known risks of allogeneic transfusion. These include viral hepTable 2 Cost benefits of acute perioperative normovolaemic haemodilution. Costs were obtained from Swansea NHS Trust in 2006 Item
Cost (£ sterling)
1 unit of cross matched of leucocyte depleted blood Two collection bags for haemodilution Savings made per patient given a transfusion assuming a mean allogeneic transfusion requirement of: 2 units 4 units Cost of episode of transfusion incompatibility
165 12
318 618 Not known
I.R. Parkin et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
atitis, human immunodeficiency virus (HIV), and variant Creutzfeldt-Jakob disease (vCJD). Head and neck operations are often associated with serious blood loss;7–9 transfusions are reportedly required in 14% to 80% of patients undergoing resections for head and neck cancer. A reason for such a wide range is perhaps the “trigger” haemoglobin concentration that indicates a transfusion is necessary and the type of operation done. Bilateral radical neck dissections with free flaps are more likely to have more blood loss than unilateral functional neck dissection.7 On a physiological basis, with each millilitre of blood lost during the operation, the dilutional effects of APNH will reduce the packed cell volume, so loss of red blood cell mass will be lower. A further reason for avoiding allogeneic blood transfusion in patients with cancer is its reported immunosuppressive effects. These were first described after transplants in the 1970s.10 The relation between allogeneic transfusion and increase in recurrent colorectal, lung, breast and renal cancer has been reported since the 1980s. Specific to patients with head and neck disease there has been a small number of retrospective studies11,12 that compared recurrence rates of head and neck cancer with those having allogeneic blood transfusion. The results have been conflicting. The main difficulty in identifying that allogeneic blood transfusion may be associated with recurrence is the number of variables present that can account for recurrence. Szakmany et al.12 & Tangiguchi et al.13 have suggested that allogeneic blood transfusion of 3 or more units might confer a worse prognosis on patients having operations for head and neck cancer. They reported that a possible underlying cause is dose related immunosuppression. A known advantage of APNH patients with head and neck cancer having free flap transfers is the effect of iatrogenic anaemia and subsequently lowered viscosity on survival of the free flap. Earle et al.14 first reported that reduced blood viscosity resulted in improvement in survival of a skin flap. They hypothesised that flow in the flap is inversely associated with blood viscosity. As haemoglobin is the main component of blood, which governs viscosity; so low haemoglobin concentrations indicate low blood viscosity which improves survival of the flap. Animal studies15–17 that studied the effect of haemodilution on the microcirculation and survival of the flap showed that an anaemic state is an effective method of improving survival. Qiao et al.18 reported a 93.3% flap survival rate of 30 free flaps in patients who had APNH and autologous blood transfusion. Other methods that help to reduce blood loss include meticulous surgical technique and good communication with the anaesthetist. Controlled hypotension is indicated as a means of reducing blood loss in maxillofacial procedures.19 This is a reached with a combination of anaesthetic agents and positioning of the patient. In this unit, the patient is tilted 300 head up, and the operating table broken with the legs raised to heart level. Advances that have helped to reduce intraoperative blood loss are the introduction of the ultrasonic scalpel20
389
and tissue fibrin sealants. A Cochrane review into the use of fibrin sealants has shown they are efficacious in reducing both postoperative blood loss and the need for postoperative transfusion.21 Allogeneic transfusion should therefore be avoided if possible.
References 1. Boulton FE, James V. Guidelines for policies on alternatives to allogeneic blood transfusion. I. Predeposit autologous blood donation and transfusion. British Committee for Standards in Haematology, Transfusion Task Force. Transfus Med 1997;5:354–65. 2. Napier JAF, Bruce M, Chapman JK, et al. Guidelines for autologous transfusion. II. Pre-operative haemodilution and cell salvage. British Committee for Standards in Haematology Blood Transfusion Task Force. Autologous Transfusion Working Party. Br J Anaesth 1997;78:768–71. 3. Code of practice for the surgical management of Jehovah’s Witnesses. London: Royal College of Surgeons of England, 2002. 4. Hill J, James V. Survey of autologous blood transfusion activity in England (2001). Guidelines for autologous transfusion. I. Pre-operative autologous donation. Transfus Med 2003;13:9–15. 5. Varney SJ, Guest JF. The annual cost of blood transfusion in the UK. Transfus Med 2003;13:205–18. 6. Habler O, Schwenzer K, Zimmer K, Prager M, Konig U, Oppenrieder A, et al. Effects of standardized acute normovolemic haemodilution on intraoperative allogeneic blood transfusion in patients undergoing major maxillofacial surgery. Int J Oral Maxillofac Surg 2004;33:467– 75. 7. Dulguerov P, Quinodoz D, Allal AS, Tassonyi E, Beris P. Blood transfusion requirements in otolaryngology-head and neck surgery. Acta Otolaryngol 1998;118:744–7. 8. Marchiori C, Fede A, Bassano M, Nieri A. Normovolemic hemodilution in head and neck surgery. Arch Otorhinolaryngol 1989;246:333– 5. 9. Krupp NL, Weinstein G, Chaliam A, Berlin JA, Wolf P, Weber R. Validation of a transfusion prediction model in head and neck cancer surgery. Arch Otolaryngol Head Neck Surg 2003;129:1297–302. 10. Opelz G, Sengar DPS, Mickey MR, Terasaki PI. Effect of blood transfusions on subsequent kidney transplants. Transplant Proc 1973;5:253– 9. 11. Moir MS, Samy RN, Hanasono MM, Terris DJ. Autologous and heterologous blood transfusion in head and neck cancer surgery. Arch Otolaryngol Head Neck Surg 1999;125:864–8. 12. Szakmany T, Dodd M, Dempsey GA, et al. The influence of allogeneic blood transfusion in patients having free flap primary surgery for oral and oropharyngeal squamous cell carcinoma. Br J Cancer 2006;94:647– 53. 13. Taniguchi Y, Okura M. Prognostic significance of perioperative blood transfusion in oral cavity squamous cell carcinoma. Head Neck 2003;5:931–6. 14. Earle AS, Fratianne RB, Nunez FD. The relationship of hematocrit levels to skin flap survival in the dog. Plast Reconstr Surg 1974;54:341– 4. 15. Velanovich V, Smith DJ, Robson MC, Heggers JP. The effect of hemoglobin and hematocrit levels on free flap survival. Am Surg 1988;54:659–63. 16. Desyatnikova S, Winslow C, Cohen JI, Wax MK. Effect of anemia on the fasciocutaenous flap survival in a rat model. Laryngoscope 2001;111:572–5. 17. Tuz M, Eroglu E, Dogru H, Delibas N, Tunc B, Uygur K. The effect of replacement fluids and normovolaemic haemodilution on the survival of dorsal skin flaps in rats. Clin Otolaryngol 2004;29:80– 3.
390
I.R. Parkin et al. / British Journal of Oral and Maxillofacial Surgery 46 (2008) 387–390
18. Qiao Q, Zhou G, Chen GY, Ling YC, Zhang F, Bunke HJ. Application of hemodilution in microsurgical free flap transplantation. Microsurgery 1996;17:487–90. 19. Degoute C. Controlled hypotension: a guide to drug choice. Drugs 2007;67:1053–76.
20. Kos M, Engelke W. Advantages of a new technique of neck dissection using an ultrasonic scalpel. J Craniomaxillofac Surg 2007;35:10–4. 21. Carless PA, Henry DA, Anthony DM. Fibrin sealant use for minimising peri-operative allogeneic blood transfusion. Cochrane Database of Systematic Reviews 2003;(2). CD004171.