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ORIGINAL ARTICLE Table of Contents   
Year : 2010  |  Volume : 13  |  Issue : 1  |  Page : 34-38
Acute normovolemic hemodilution is not beneficial in patients undergoing primary elective valve surgery

1 Department of Anaesthesiology & Intensive Care, G.B. Pant Hospital, New Delhi, India
2 Department of Cardiothoracic Surgery, G.B. Pant Hospital, New Delhi, India

Click here for correspondence address and email

Date of Submission22-Sep-2009
Date of Acceptance08-Dec-2009
Date of Web Publication11-Jan-2010


The objective of this study was to evaluate the effectiveness of acute normovolemic hemodilution (ANH) as a sole method of reducing allogenic blood requirement in patients undergoing primary elective valve surgery. One hundred eighty eight patients undergoing primary elective valve surgery were prospectively randomized into two groups: Group I (n=100) acted as control and in Group II (n=88) autologous blood was removed (10% of estimated blood volume in patients with hemoglobin (Hb) >12g% and 7% when the Hb was <12g%) in the pre-cardiopulmonary bypass (CPB) period for subsequent re-transfusion after protamine administration. The autologous blood withdrawn was replaced simultaneously with an equal volume of hydroxyl-ethyl starch solution. Banked blood was transfused in both the groups when Hb was ≤6g % on CPB and ≤8g% after CPB. Platelets were transfused when the count fell to <100´10 9 /L and fresh frozen plasma (FFP) was transfused whenever there was diffuse bleeding with laboratory evidence of coagulopathy. The two groups were comparable as regards demographic data, type of surgical procedures performed, duration of CPB and ischemia, duration of elective ventilation and re-exploration for excessive bleeding. The autologous blood withdrawn in patients with Hb≥12g% was 288.3±69.4 mL and 244.4±41.3 mL with Hb<12g% (P=NS). The Hb concentration (g %) was comparable pre-operatively (Group I= 12.1±1.6, Group II= 12.4±1.4), on postoperative day 1 (Group I =10.3±1.1, Group II= 10.6±1.2) and day 7 (Group I = 10.9±1.5, Group II=10.4±1.5). However, the lowest Hb recorded on CPB was significantly lower in Group II (Group I =7.7±1.2, Group II=6.7±0.9, p0 <0.05). There was no difference in the chest tube drainage (Group I =747.2±276.5 mL, Group II=527.6±399.5 mL), blood transfusion (Group I=1.1±1.0 units vs. Group II=1.3±1.0 units intra-operatively and Group I=1.7±1.2 units vs. Group II=1.7±1.4 units post-operatively) and FFP transfusion (Group I =581.4±263.4 mL, Group II=546.5±267.8 mL) in the two groups. We conclude that low volume autologous blood pre-donation does not seem to provide any added advantage as a sole method of reducing allogenic blood requirement in primary elective valve surgery.

Keywords: Acute normovolemic hemodilution, elective valve surgery, cardiac surgery

How to cite this article:
Virmani S, Tempe DK, Pandey BC, Cheema AS, Datt V, Garg M, Banerjee A, Wadhera A. Acute normovolemic hemodilution is not beneficial in patients undergoing primary elective valve surgery. Ann Card Anaesth 2010;13:34-8

How to cite this URL:
Virmani S, Tempe DK, Pandey BC, Cheema AS, Datt V, Garg M, Banerjee A, Wadhera A. Acute normovolemic hemodilution is not beneficial in patients undergoing primary elective valve surgery. Ann Card Anaesth [serial online] 2010 [cited 2022 Dec 3];13:34-8. Available from:

   Introduction Top

The fundamental principle of acute normovolemic hemodilution (ANH) is the creation and tolerance of intra-operative anemia. The preoperative dilution of circulating blood volume reduces the amount of red blood cells and plasma constituents lost during surgical bleeding. It has been suggested as an inexpensive and effective means of reducing allogenic blood exposure in a report of the American Society of Anesthesiologists Task force on Blood component therapy. [1] A meta-analysis by Bryson et al. [2] in 1998 and another by Segal et al. [3] in 2004 on the role of ANH in reducing the peri-operative allogenic transfusion showed that the systematic review and statistical summary of published trials of ANH were inconclusive. When all trials of ANH were combined, ANH was seen to be effective in reducing both the likelihood of exposure to allogenic blood and the volume of blood transfused. [1] However, the presence of substantial and unexplained heterogeneity suggested that the benefit of ANH was inconsistent and not supportive of this overview. The evidence suggested that the efficacy of ANH is likely to be small (reducing the risk of transfusion by 10 percent and a modest hemostatic benefit) when compared to usual care. [3] A study of 100 patients in 1996 by the authors [4] also did not show any benefit with ANH as a sole method in patients undergoing valve surgery. A decade later the authors hypothesized that with the improvement in the overall expertise of the entire team, be it surgeon, anesthetist, perfusionist or other technical staff working in the operation theater, and with the availability of improved technology such as routine use of membrane oxygenators and improved CPB machine (Sarns 9000 instead of Sarns 7000), there would be an overall decrease in the transfusion requirement in patients undergoing cardiac surgery. Therefore, the technique of ANH should make a significant impact on transfusion requirements and reduce the burden on blood banks. Thus, the present study was undertaken with the objective to study the effectiveness of ANH as a sole method of reducing allogenic blood requirement in patients undergoing elective valve surgery.

   Materials and Methods Top

After obtaining institutional review board approval, one hundred and eighty eight patients undergoing primary elective valve surgery were prospectively randomized by computer generated random number sequence into two groups. Group I (n=100) acted as control. In Group II (n=88), autologous blood was removed soon after the anesthetic induction before the patient was heparinized. Ten percent of the estimated blood volume (75/65 mL/kg body weight for males/females respectively) was removed when the baseline hemoglobin (Hb) was ≥12g% and 7% when Hb<12g%. The blood removed was simultaneously replaced with an equivalent amount of hydroxyethyl starch (130/0.4 or 200/0.5). The collected blood was re-transfused at the termination of CPB after protamine administration. Exclusion criteria were Hb<10g%, deranged liver function tests, hemorrhagic diathesis, ejection fraction <30% and renal or respiratory insufficiency.

All patients were premedicated with morphine 0.2 mg/Kg body weight and promethazine 25 mg intramuscularly one hour prior to surgery. In the operating room, a 23 G cannula and radial artery cannula was inserted under local anesthesia. Anesthesia was induced with fentanyl 10 to 20 µg/kg, thiopentone sodium 50-100 mg and muscle relaxation was achieved with pancuronium bromide, vecuronium bromide or rocuronium hydrochloride depending on the lesion and baseline heart rate. Nitrous oxide in oxygen was administered [fractional inspired oxygen concentration (FiO 2 ) 0.5] before intubation. FiO 2 was reduced to 0.35 after intubation and increased to 1 once the CPB was initiated. In Group I, collection of autologous blood was not performed (control). In Group II autologous blood was removed via the central venous catheter and stored at room temperature in a CPD-bag for re-transfusion after protamine administration. Standard CPB technique was followed using non-pulsatile flow @ 2-2.4 L/min/m 2 maintaining a temperature of 28-32°C with a membrane oxygenator (Affinity, Medtronic Inc. Minneapolis MN) and roller pump, with initial crystalloid prime volume of 1000 mL of lactated Ringer's solution and 250 mL of 18% mannitol. Cardiac arrest was induced and maintained using cold potassium containing crystalloid cardioplegic solution delivered anterogradely using the cardioplegia delivery system and a 14 G needle in the aortic root. Patients were heparinized with 300 units/kg of heparin, 5 min before aortic cannulation and a further dose of 150 units/kg every hour during CPB with activated coagulation time (ACT) maintained at >480 seconds. After termination of CPB, heparin was reversed with protamine in a ratio of 1.3 mg for every 100 units of initial dose of heparin.

Criteria for transfusion

Banked blood was added to the prime when Hb was ≤6 g% on CPB. The blood left in the oxygenator was re-infused at the termination of CPB. Autologous blood that was collected was administered to all patients in Group II after protamine administration. Banked blood was used subsequently in both the groups if Hb was ≤8g%. Platelets were administered when the count decreased to <100×10 9 /L and fresh frozen plasma (FFP) was transfused whenever there was diffuse bleeding with laboratory evidence of coagulopathy.

Data recorded

Hemoglobin was measured pre-operatively, lowest on CPB and on the post-operative day1 and 7, Platelet count and prothrombin time (PT) were measured pre-operatively and on post-operative day 1, Bleeding time (BT) and coagulation time (CT) were measured pre-operatively. Total blood loss, intubation time, CPB time, ischemia time and any re-exploration for excessive bleeding were noted.

Statistical analysis was done with Statistical Package for the Social Sciences 10, Chicago. Differences between the group means were evaluated with Student's t test and P0 <0.05 was considered statistically significant. All values are expressed as means±standard deviation (SD). In the author's institution approximately eight hundred valve surgeries are being performed per year with an average requirement of one to three units of banked blood. Therefore the sample size (with 90% power) calculated for reducing the likelihood of blood transfusion by one unit (33%) was 41 patients in each group.

   Results Top

There were no significant differences in the demographic data, operative data, duration of CPB, ischemia and elective ventilation. Five patients in Group I and two in Group II were re-explored for excessive bleeding [Table 1] and [Table 2]. There were no complications that might have been related to the autologous blood transfusion. Preoperatively, fifty nine patients in Group I and fifty three patients in Group II had Hb≥12g%. The mean Hb was 13.1±1.1 and 13.3±1.0g% (P=NS) in Groups I and II respectively. Forty one patients in Group I and 35 patients in Group II had Hb<12g% with mean Hb being 10.6±0.8 and 11.0±5.7g% (P<0.05) in Groups I and II respectively. The autologous blood withdrawn in patients with Hb≥12g% was 288.3±69.4 mL and with Hb<12g% was 244.4±41.3 mL (P=NS). [Table 3] shows the Hb concentrations at various stages. On the post-operative day 1 and 7, the Hb levels decreased significantly in both the groups but, there was no statistical difference between the groups. The lowest recorded Hb on CPB was significantly lower in Group II (ANH group) when compared with Group I. All the patients had normal PT, platelet count, bleeding time and clotting time before surgery. There was no significant difference in the platelet count and PT after surgery [Table 4]. The baseline and post-protamine ACT were similar in the two groups and although, the chest drain was less in Group II, the difference did not attain statistical significance [Table 5]. [Table 6] shows the intravenous fluids and banked blood transfusion in the two groups. In Group II, the intra-operative volume of colloids was significantly more (291.5±105.9 mL vs. 76.3±170.6 mL, P <0.001) and in Group I the intra-operative volume of crystalloids transfused was significantly more (266.7±2937 vs. 62.5±173.9, P <0.01). The colloids and crystalloids infused in the post-operative period were not statistically different in the two groups. In one patient in Group I and 5 patients in Group II ( P =NS), bank blood was added to the oxygenator during CPB. The intra-operative and post-operative bank blood requirement in the two groups was not significantly different. No allogenic blood was transfused in 3 patients in Group I and in 4 patients in Group II ( P =NS).

   Discussion Top

Theoretically sequestration of patient's own blood before CPB requires minimal pre-operative preparation and is suitable for emergency and elective procedures. The use of autologous blood in this manner can avoid transfusion transmitted infections, immune mediated complications, graft vs. host disease, acute hemolytic reactions and patient's anxiety about receiving other people's blood. [5],[6],[7] The ANH is however, not without any complications and it has been seen that acute hemolytic reactions due to mistaken transfusion to a different patient, [4] bacterial contamination of collected blood, [8] hemodynamic instability and acute coronary events [9] can occur. No such complications were noted in the present study.

Cardiac surgery is responsible for approximately 20% of allogenic blood transfusion. [10] However, in the last 20 years, the transfusion rate has decreased from 100% to 27% - 92%. [10] This has been mainly due to the improvement in the technology and surgical expertise as well as better understanding of the physiology of blood transfusion which has led to lower transfusion trigger. In addition, the use of antifibrinolytics and autologous blood transfusion have also contributed to the decrease in transfusion requirements. [11] The efficacy of ANH is still controversial with some studies demonstrating the effectiveness of ANH in cardiac surgery. These have mostly been in patients undergoing coronary artery bypass grafting in whom large volume of autologous blood (700-1000 mL) was withdrawn. [12],[13],[14] This may have been possible due to higher preoperative Hb levels as well as large body surface area in these patients. A few others have demonstrated that withdrawal of 5-8 mL/kg [15] or 400 mL [11] of blood was not effective. In India, the main cause of valvular heart disease is rheumatic fever, which affects children belonging to low socio-economic status who have poor nutrition. Due to cardiac cachexia the patients presenting for valve replacement are small built, emaciated, underweight with low blood volume. Therefore, in the present study the preoperative Hb and the small size of the patients were the limiting factors that allowed us to withdraw only 270.85±63.34 mL of blood. There are quite a few formulae that are available for calculating the amount of autologous blood that can be withdrawn. We preferred to withdraw 10% of estimated blood volume in patients with Hb≥12g% and 7% in patients with Hb≥10g%, which allowed a Hb of approximately 6g% on CPB following hemodilution. Transfusion of this small volume of autologous blood in the present patient population did not offer any benefit.

The blood withdrawn from the patient in the pre-bypass period contains essential clotting factors since this blood has not been exposed to the destructive action of the pump and the oxygenator. Although, the chest drain was less in Group II, the difference did not attain statistical significance. It is difficult to comment on whether this reduced bleeding in the ANH group could be related to autologous transfusion and whether including more number of patients could have attained the statistical significance. Yeh et al. [16] have reported that with just one unit of autologous blood there is no difference in the platelet count or post-bypass blood loss. Segal et al. [3] in their meta-analysis report that only a modest hemostatic benefit is seen with ANH and that the clinical benefit of reducing blood loss by small volume is unknown. The results of this study are similar to the ones reported by the authors earlier in 1996 [4] in 50 patients, wherein bubble oxygenator was used and Hb of ≤5g% was accepted on CPB, and no benefit was obtained by ANH. The chest tube drain, the transfusion requirements, the CPB time and aortic cross-clamp time were also similar in the two studies. Therefore, it seems that a status quo is maintained in terms of the utility of ANH in this subset of patients even with the use of membrane oxygenator and a gap of 12 years.

In various studies [3] the acceptable hematocrit has been variable but the current guidelines by The Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists (STS-SCA) [17] recommend Hb of 7g % unless there is a risk of organ ischemia such as coronary, cerebrovascular or renal. The authors accepted a Hb of 8g % as per the practice followed in their centre. It is difficult to answer, if a lower hematocrit as per the STS and SCA guidelines of 7g% would make the ANH beneficial in these small, young patients undergoing valve surgery.

There is also no benefit shown in adding ANH to other blood conservation techniques (intra-operative hemodilution and platelet rich plasma collection [18] or to intravenous aprotinin and cell saving. [19]

The study was prospective and randomized, but the principal limitations were that it was a non blinded study and several surgeons had participated.

   Conclusion Top

Autologous blood pre-donation does not seem to provide any added advantage as a sole method of reducing allogenic blood requirement in primary elective valve surgery in India.

   References Top

1.American Society of Anesthesiologists Task Force on Blood Component Therapy: a report by the American Society of Anesthesiologists Task Force on Blood Component Therapy. Anesthesiology 1996;84:732-47.  Back to cited text no. 1      
2.Bryson GL, Laupacis A, Wells GA. Does acute normovolemic hemodilution reduce perioperative allogeneic transfusion? A meta-analysis. The International Study of Perioperative Transfusion. Anesth Analg 1998;86:9-15.   Back to cited text no. 2      
3.Segal JB, Blasco-Colmenares E, Norris EJ, Guallar E. Preoperative acute normovolemic hemodilution: a meta-analysis. Transfusion 2004;44:632-44.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]  
4.Tempe D, Bajwa R, Cooper A, Nag B, Tomar AS, Khanna SK, et al. Blood conservation in small adults undergoing valve surgery. J Cardiothorac Vasc Anesth 1996;10:502-6.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]  
5.Marcucci C, Madjdpour C, Spahn DR. Allogeneic blood transfusions: benefit, risks and clinical indications in countries with a low or high human development index. Br Med Bull 2004;70:15-28.   Back to cited text no. 5  [PUBMED]  [FULLTEXT]  
6.Williamson LM, Lowe S, Love EM, Cohen H, Soldan K, McClelland DB, et al. Serious hazards of transfusion (SHOT) initiative: analysis of the first two annual reports. BMJ 1999;319:16-9.  Back to cited text no. 6  [PUBMED]  [FULLTEXT]  
7.Lee SJ, Liljas B, Churchill WH, Popovsky MA, Stowell CP, Cannon ME, et al. Perceptions and preferences of autologous blood donors. Transfusion 1998;38:757-63.  Back to cited text no. 7  [PUBMED]  [FULLTEXT]  
8.Goodnough LT, Brecher ME, Kanter MH, AuBuchon JP. Transfusion medicine. First of two parts-blood transfusion. N Engl J Med 1999;340:438-47.  Back to cited text no. 8      
9.Popovsky MA, Whitaker B, Arnold NL. Severe outcomes of allogeneic and autologous blood donation: frequency and characterization. Transfusion 1995;35:734-37.  Back to cited text no. 9  [PUBMED]  [FULLTEXT]  
10.Stover EP, Siegel LC, Parks R, Levin J, Body SC, Maddi R, et al. Variability in transfusion practice for coronary artery bypass surgery persists despite national consensus guidelines: a 24-institution study. Institutions of the Multicenter Study of Perioperative Ischemia Research Group. Anesthesiology 1998;88:327-33.  Back to cited text no. 10      
11.Vedrinne C, Girard C, Jegaden O, Blanc P, Bouvier H, Ffrench P, et al. Reduction in blood loss and blood use after cardiopulmonary bypass with high-dose aprotinin versus autologous fresh whole blood transfusion. J Cardiothorac Vasc Anesth 1992;6:319-23.  Back to cited text no. 11  [PUBMED]  [FULLTEXT]  
12.Hallowell P, Bland JH, Buckley MJ, Lowenstein E. Transfusion of fresh autologous blood in open-heart surgery. A method for reducing bank blood requirements. J Thorac Cardiovasc Surg 1972;64:941-8.  Back to cited text no. 12      
13.Kaplan JA, Cannarella C, Jones EL, Kutner MH, Hatcher CR Jr, Dunbar RW. Autologous blood transfusion during cardiac surgery. A re-evaluation of three methods. J Thorac Cardiovasc Surg 1977;74:4-10.   Back to cited text no. 13      
14.Wagstaffe JG, Clarke AD, Jackson PW. Reduction of blood loss by restoration of platelet levels using fresh autologous blood after cardiopulmonary bypass. Thorax 1972;27:410-4.  Back to cited text no. 14  [PUBMED]  [FULLTEXT]  
15.Casati V, Speziali G, D'Alessandro C, Cianchi C, Antonietta Grasso M, Spagnolo S, et al. Intraoperative low-volume acute normovolemic hemodilution in adult open-heart surgery. Anesthesiology 2002;97:367-73.  Back to cited text no. 15  [PUBMED]  [FULLTEXT]  
16.Yeh T Jr, Shelton L, Yeh TJ. Blood loss and bank blood requirement in coronary bypass surgery. Ann Thorac Surg 1978;26:11-6.  Back to cited text no. 16  [PUBMED]  [FULLTEXT]  
17.Ferraris VA, Ferraris SP, Saha SP, Hessel EA 2nd, Haan CK, Royston BD, et al. Perioperative blood transfusion and blood conservation in cardiac surgery: the Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists clinical practice guideline. Ann Thorac Surg 2007;83:27-86.  Back to cited text no. 17      
18.Triulzi DJ, Gilmor GD, Ness PM, Baumgartner WA, Schultheis LW. Efficacy of autologous fresh whole blood or platelet-rich plasma in adult cardiac surgery. Transfusion 1995;35:627-34.  Back to cited text no. 18  [PUBMED]  [FULLTEXT]  
19.Höhn L, Schweizer A, Licker M, Morel DR. Absence of beneficial effect of acute normovolemic hemodilution combined with aprotinin on allogeneic blood transfusion requirements in cardiac surgery. Anesthesiology 2002;96:276-82.  Back to cited text no. 19      

Correspondence Address:
Sanjula Virmani
Department of Anaesthesiology & Intensive Care, G.B. Pant Hospital, New Delhi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-9784.58832

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