Table of Contents  
ORIGINAL ARTICLE
Year : 2015  |  Volume : 8  |  Issue : 4  |  Page : 474-480  

Predeposit autologous blood transfusion: Do we require to promote it?


1 Department of General Surgery, Dr. D. Y. Patil Medical College, Pimpri, Pune, Maharashtra, India
2 Department of Pathology, Dr. D. Y. Patil Medical College, Pimpri, Pune, Maharashtra, India
3 Department of Community Medicine, Army College of Medical Sciences, Delhi Cantonment, New Delhi, India
4 Department of Surgery, Dr. D. Y. Patil Medical College, Pimpri, Pune, Maharashtra, India

Date of Web Publication14-Jul-2015

Correspondence Address:
Somnath Gooptu
Dr. D. Y. Patil Medical College, Pimpri, Pune, Maharashtra
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-2870.160788

Rights and Permissions
  Abstract 

Introduction: Safest blood a patient can receive is his own. Quest for safe blood transfusion has remained of prime concern. To meet this aspiration, various forms of autologous blood transfusions can be practiced. It is especially suitable for patients with rare blood groups and religious sects such as Jehovah's witness autologous transfusion is extremely safe. Cross matching is not required; iso-immunization to a foreign body is excluded. Fear of transfusion transmissible disease can be ignored. Therefore, autologous blood transfusion is required to be revisited. Materials and Methods: This is a prospective study carried out at Padmashree Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pune between July 2010 and May 2012. Study comprised of 100 patients divided into two groups, autologous and homologous. Benefits of autologous transfusion were studied. Results: There was no significant change in hematocrit and blood parameters after blood donation. That is mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration (P < 0.001) after blood donation. Only one complication of vasovagal syncope was observed at the time of blood donation. Conclusion: Autologous blood transfusion is safe. Easy alternative to be practiced in elective surgeries, especially in patients with rare blood group or believers of Jehovah's witness faith. It helps to reduce the shortfall in national blood inventory. Autologous blood donation should be practiced whenever possible.

Keywords: Autologous blood transfusion, preoperative autologous blood transfusion, safe blood


How to cite this article:
Singh G, Kumar A, Kumar H, Ali I, Bawa AP, Gooptu S. Predeposit autologous blood transfusion: Do we require to promote it?. Med J DY Patil Univ 2015;8:474-80

How to cite this URL:
Singh G, Kumar A, Kumar H, Ali I, Bawa AP, Gooptu S. Predeposit autologous blood transfusion: Do we require to promote it?. Med J DY Patil Univ [serial online] 2015 [cited 2019 Nov 19];8:474-80. Available from: http://www.mjdrdypu.org/text.asp?2015/8/4/474/160788


  Introduction Top


There has been considerable advancement in surgical transfusion practices worldwide. Advancement in technology and increasing use of specific blood component has resulted in the evolution of safer surgical practices. Quest for safe blood transfusion has remained a prime concern. Safest blood a patient can receive is his own. Therefore, autologous blood transfusion is required to be revisited.

Autologous blood transfusion is extremely safe. Cross matching is not required, iso-immunization to a foreign protein is excluded, allogenic blood is conserved for those who need it particularly in emergencies and the fear of transfusion transmissible disease can be ignored. [1]

Autologous transfusion can be practiced for most elective operations. It is indicated for patients with very rare blood groups or complex red blood cell antibodies for whom it is difficult to find compatible blood, and also for religious sects like Jehovah's witnesses in whom only intra-operative cell salvage is permissible. [2]

This study aimed to assess the benefits of autologous blood transfusion as compared to homologous transfusion.


  Materials and Methods Top


The present study is a comparative study, undertaken in the Department of General Surgery, Dr. D. Y. Patil Medical College, Pimpri, Pune between July 2010 and May 2012.

Patients were randomly divided into two groups, Group A and Group B.

Clearance from Institutional Ethical Committee was obtained before the start of the study.

Inclusion criteria

Group A - all patient willing for autologous donation, patient having hemoglobin (Hb) level of >12.5 g/dL and hematocrit of >33%, operative procedure in whom blood loss is anticipated during surgery and blood is required to be kept ready in blood bank. For example-open cholecystectomy, above knee/below knee amputation, thyroid surgery, elective exploratory laparotomy (for benign/malignant condition). Radical mastectomy, surgeries on kidney, oral carcinoma with neck dissection.

Exclusion criteria

Patients with co-morbid condition (diabetes mellitus, hypertension, cardiac diseases, and respiratory diseases). Recent systemic infection, poor venous access.

No comparison was made for the type of surgery for Group A and Group B.

Informed and written consent were obtained from all the patients before the start of the study and patients were counseled regarding details of the procedure. Patients were examined, and details recorded as per proforma. Hb level, hematocrit, red cell indices (i.e., mean corpuscular volume [MCV], mean corpuscular hemoglobin [MCH], mean corpuscular hemoglobin concentration [MCHC]) of the patients were recorded before the start of the study besides blood tested for HIV, hepatitis B surface antigen, hepatitis C virus, Venereal Disease Research Laboratory, malaria parasites, atypical antibodies of the patients, and other appropriate investigations were also done.

Patients were randomly divided into two groups, Group A and Group B.

Group A: Included autologous group in whom one unit of blood was collected into bags containing an additive system, anticoagulant-preservative (citrate phosphate dextrose adenine) 5-7 days before surgery through phlebotomy in one arm. Collected blood was kept in the blood bank between 1°C and 6°C. These units were labeled as "autologous" and stored separately in the blood bank. Laboratory values (in terms of Hb level, packed cell volume and red cell indices) were compared by assessing these values just before blood collection and a day before the surgery. The blood was transfused intraoperatively or postoperatively if indicated (if Hb level <10 g/dL). If the blood was not used for 10 days, it was discarded.

Group B: Comprised of patients in whom homologous blood was used during surgery or postoperatively. This group was included primarily to record complications and the cost and compare it with Group "A."

The two groups were compared with respect to cost effectiveness and complications. Pre- and post-donation and posttransfusion Hb and hematocrit levels were studied in Group A patients. Chi-square test used for the analysis of the results. Patients were followed up to 1-month after surgery in both groups.


  Results Top


Of 100 patients studied, 50 were of Group A (autologous) and 50 were of Group B (homologous). In Group A, male:female ratio was 1.15:1 and among Group B, male:female ratio was 1:1.2.

All patients in both groups were of age between 20 and 60 years. In Group A, the maximum number of patients was of age group 41-50 years. In Group B, the maximum number of patients was of age group 51-60.

There was no significant difference between mean age of two group (P = 0.22).

Mean Hb and hematocrit level in autologous group was 11.5 g/dL (range: −12.8-11 g/dL) and 35.78% (range: 42-33%), respectively, at time of donation and 10.72 g/dL (range: 12.1-11 g/dL) and 33.31 (range: −38-29%) postdonation but preoperatively (P = 0.001, t = 15.88) [Table 1].
Table 1: Mean values of hemoglobin, hematocrit before and after blood donation

Click here to view


Among autologous blood donors (Group A) difference of mean Hb level before donation and postdonation was statistically significant as evident by P < 0.001, t = 15.88, but not clinically relevant, similarly difference of mean of hematocrit level before donation and postdonation was again not relevant clinically, but significant statistically as indicated by P < 0.001 and t = 7.49 and margin of difference in means of hematocrit level between pre-and post-donation was 2.47% only.

Change in values of red cell indices was also not statistically significant after collection of blood from autologous donor except for MCH (P < 0.0001) although it was statistically significant but not relevant clinically [Table 2].
Table 2: Mean values of red cell indices before and after blood donation

Click here to view


Difference between mean of predonation and postdonation red cell indices level that is MCV, MCH, MCHC it was statistically significant for MCH P < 0.0001, t = 4.68 but not relevant clinically [Table 3]. However, P > 0.05, t = 1.42 of predonation and postdonation MCV level were statistically not significant, similarly, P > 0.05, t = 0.22 of pre-and post-donation MCHC level were not clinically relevant.
Table 3: Mean red cell indices of both autologous and homologous group

Click here to view


Comparing the cost of blood, Group A was found to be 150 rupees cheaper than Group B [Table 4].
Table 4: Comparison of cost for autologous and homologous transfusion

Click here to view


Fifty bags of autologous blood were stored in the blood bank and were given to the same patient if indicated intraoperatively or postoperatively and if Hb level felt below 10 mg/dL. Of 50 patients studied 41 required autologous blood transfusion and remaining 9 units were discarded [Table 5]. Among the 41 utilized, 25 units were used for a different type of carcinoma cases.
Table 5: Utilization of blood collected for autologous purpose

Click here to view


Two cases receiving homologous transfusion had fever with chills (maximum temperature −101°C). There was none in the case of autologous group. One female autologous donor developed mild vasovagal syncope which was relieved after rest [Table 6].
Table 6: Comparison of complications between Group "A" and Group "B"

Click here to view



  Discussion Top


The first attempt at autologous transfusion was made with re-infusion of washed blood with the purpose of surgical and obstetrical patient's resuscitation. The first reference of blood-saving is indexed in the American bibliography in 1917. [3]

In 1980s and early 1990s, interest in and request for autologous collections increased significantly. This was as a result of AIDS epidemic and the awareness that transfusion -transmitted infection (TTI) cannot be totally eliminated by donor screening and testing. [4]

Various forms of autologous blood transfusion are intra-operative cell salvage, postoperative cell salvage, acute normovolemic hemodilution, predeposit autologous blood donation. Present study is concerned with preoperative blood collection only.

Preoperative blood donation is primarily employed for the procedure which needs multiple units of blood transfusions like total hip replacement, coronary artery bypass graft, etc. However, in the present study concentrates only on subjects who as per maximum surgical blood loss ordering schedule of the hospital are required to arrange and keep at least one units of blood ready in the blood bank.

In the study of Yamamoto et al., efficacy and problems associated with autologous blood transfusion was studied and they concluded that of the 253 patients, who underwent total hip arthroplasty and received autologous blood transfusion, the rate of avoidance of homologous blood transfusion was 95%. [5] The rate of avoidance of homologous transfusion was 82% in our study.

The greatest risk of autologous blood transfusion is a clerical error and bacterial contamination of autologous unit. [1]

In UK, establishment of serious hazards of transfusion scheme has become an international "gold standard" in hemovigilance which involve voluntary reporting system of all adverse reaction in order to improve standards of hospital transfusion practice. [6]

The term noninfectious serious hazards of transfusion (NISHOT) reaction was first described in 2000 American Association of Blood Bank (AABB) bulletin that includes all noninfectious complication. Condition included under NISHOT is categorized into immune-mediated and nonimmune mediated. Immune-mediated are hemolytic transfusion reaction, febrile nonhemolytic transfusion reaction, allergic/urticarial/anaphylactic transfusion reactions, transfusion-related acute lung injury, posttransfusion purpura, transfusion-associated graft versus host disease, microchimerism, transfusion-related immunomodulation, alloimmunization. Nonimmune mediated are septic transfusion reactions, nonimmune hemolysis, mis-transfusion, transfusion-associated circulatory overload, metabolic derangements, coagulopathic complications from massive transfusion, complications from red cell storage lesions, over/under transfusion, iron overload. [7]

Transfusion of blood and blood component is associated with increased risk of transfusion TTI. The risk per unit transfused of HIV is 1:1,900,000 whereas hepatitis C and B virus transmission risk is 1:1,600,000 and 1:63,000s, respectively. [8] Elaborate and strict donor screening, sensitive ELISA testing and introduction of nucleic acid testing (NAT) has considerably reduced risk of TTI in developed countries. However, such data are lacking in developing countries because of nonuniformity in the screening procedure despite mandatory testing by law, financial constraints of the government in introducing NAT, lack of trained personnel and look back policy. [8]

Our study showed no incidence of NISHOT among autologous group whereas two cases of febrile nonhemolytic transfusion reaction in the form of fever with chills were noted among homologous group as sepsis and hemolysis was ruled out. In the case of autologous transfusion, adverse reaction can be easily prevented by meticulous labeling, maintaining the chain, preventing the bag from bacterial contamination. It has been observed that there is a great risk of clerical error resulting in transfusion of the wrong unit.

According to WHO statics of blood safety, 43% of donated blood in the developing countries is not screened for all relevant TTIs thus 80% of world's population in developing countries has access to only 20% of the world's safe blood supply. [9] Moreover, in India, only 52% of total blood collection is from voluntary donors as compared to 100% in West. Thus, 48% of country's blood collection is from replacement or relative donor who donates under stress. [10] Hence, autologous blood donation would provide a safe alternative for patients in a specific condition. [9]

The change in values of red cell indices was not statistically significant after collection of blood from autologous donor except for MCH (P < 0.0001) although it was significant statistically but not relevant clinically. Hence, it is recommended that these tests may not be undertaken while assessing and following such transfusion unless otherwise indicated.

Mean Hb and hematocrit level in autologous group was 11.5 g/dL (range: −12.8-11 g/dL) and 35.78% (range: −42-33%) at the time of donation and 10.72 (12.1 g/dL-11 g/dL) and 33.31% (38-29%) preoperatively.

There was no significant difference between predonation and postdonation Hb level to signify the anemia which would have required postponement of surgery, however, it was statistically significant (P = 0.001, t = 15.88).

According to one study, approximately 50% of patients who predonate blood prior to surgery become anemic prior to surgery [Table 2] and [Table 3]. [8] However, in our study, none of the autologous donor developed anemia prior to surgery may be because of only one unit of blood was donated prior to surgery in our study. Mean Hb and hematocrit level did not show any evidence of anemia in an autologous group which may have warranted treatment for anemia and resulted in deferment of surgery.

Autologous blood represents a source of blood for both the national blood inventory and hospital-scheduled elective surgical procedures. In our study, 50 units of blood bags were deposited in the blood bank for the autologous purpose, and 41 had been used for the same, however, 9 units of blood bags was discarded. In an analysis done for the demand - supply of the blood at our hospital it was found that there was a shortfall of 25 units for General Surgery Department and 100 units overall in monthly requirement of the hospital. Hence, the use of autologous blood would mitigate requirement of procuring blood from other sources.

Wastage was only 18% whereas it was 32-33% in the study by Saluja et al. [8] and varied between 6.9% and 56% in other studies. [11],[12] These studies primarily relate to use of autologous blood in elective orthopedic surgeries.

Comparative cost data on the various forms of autologous blood transfusion are rather subjective and inconsistent. Literature available on the effectiveness between allogenic with autologous blood transfusion is insufficient. Most of the such studies conclude that allogenic is more cost effective than autologous collection. [13] Cost of autologous blood is attributed primarily to cost involved in discarding units of blood donated but not transfused and of a more labor intensive process. [14] In our study, donation process did not involve any extra labor and cost of discarding one unit of blood was estimated to be Rs. 80. Therefore, overall cost saving was of Rs. 70. Studies which take into account increase in the risks of postoperative infection mediated by immunomodulation. Autologous blood have found to be cost effective and perhaps even cost saving. [15],[16] In our study, we did not find any increase in postoperative infection rate in either group which may affect cost effectiveness.

Use of autologous blood for other patients is controversial due to the belief that untested blood is released for homologous purpose, and autologous blood donor do not meet the stringent criteria for allogenic blood donation. Most programs do not recommend "cross-over" or use autologous blood for other patients if the intended recipient does not require it. The American medical association and the AABBs have adopted a binding policy discouraging the "cross-over" of unused autologous blood units to the allogenic (synonym: Homologous) volunteer blood supply, but by providing a positive experience in blood donation, the individual potentially can be encouraged to donate blood for others, thereby increasing the general blood pool. [17] Maharashtra state blood bank council and Indian blood bank association also do not allow for "cross-over" of unused autologous blood to the homologous volunteer blood supply. [18],[19] In our study, there was no "cross-over" of unused nine units of autologous blood which was discarded. However, it is practiced in some center, [13] after meeting the normal donor criteria, meticulous testing of blood and eliminating the clerical error.

Homologous transfusion-related immune suppression is manifest as an increased risk of postoperative infections, increased tumor recurrence after surgical resection. Study shows decrease in postoperative infection and tumor recurrence after colorectal surgery is due to less clinical potential of blood transfusion mediated immunomodulation, after autologous transfusion which may be important in tumor immunology. [20] In our study, 25 units of autologous blood was used, and 13 units of homologous blood was used for different malignant condition. No incidence of postoperative infection was encountered in either group, whereas comparison of recurrence after surgery for different malignant condition was not part of our study since it required prolonged follow-up.

The shortfall in the blood pool because of declining population of qualified, willing, and healthy voluntary donor, [21] has forced directed donation to be practiced.

Directed donation means replacement of blood used by patient from family or friend which is not as safe as patient's own blood and must not be considered equivalent to autologous donation because donors are socially pressurized to donate, are at times not able to disclose their risky sexual behavior. Directed donation constitutes 40% of blood supply in the underdeveloped world. To avoid this can be major potential stimulus for practice of autologous transfusion.

The comparative indication for the use of autologous or allogenic blood is controversial. American society of anesthesiologist task force on blood component therapy recommend Hb level <7 g/dL for transfusion. [22] Whereas transfusion at Hb >10 g/dL rarely are indicated. We fixed <10 g/dL as trigger for transfusion. The benefits of autologous and allogenic blood are similar, but the risk of autologous blood is less. Hence, the risk-benefit ratio supports the most liberal use of autologous blood. However, autologous blood should not be used merely because it is collected. [23]

The distribution of ABO blood group varies regionally, ethnically, and from one population to other. [24] In a study done by Giri et al. [24] in Parvara Medical College, Loni the distribution of ABO blood grouping was B (31.89%) >O (30.99%) >A 28.38% >AB (8.72%). In the present study distribution of "ABO" blood group was found to be 0 (40%) >A (23%) >B >(21%) >AB (16%). All negative blood groups were less frequent, and none of the patient was of AB negative blood group, so it was rarest. Autologous blood will be useful in such situation.

In a study of Kruskall et al. it is stated that benefits of transfusion with autologous predeposit blood include that it is the "safest" form of blood transfusion and it represents a source of blood for both the national blood inventory and for hospital-scheduled elective surgical procedures. [13]

Autologous blood not used in the patient from whom collected is required to be discarded as Indian and Maharashtra transfusion guidelines. In view of the shortfall in obtaining healthy voluntary donors and deficit in national blood pool, is there a case for having relook at the existing law so as to permit use of unused autologous blood for homologous purpose provided normal donor criterion is fulfilled and blood is meticulously tested.


  Conclusion Top


Autologous blood is the "safest" form of blood transfusion. It represents a source of blood for both the national blood inventory and hospital-scheduled elective surgical procedures. It is the only alternative form of blood transfusion available for patient with rare blood group and among those who do not accept homologous blood on religious grounds.

A further review of the policy of nonuse of "cross-over" is needed to meet the shortfall in national blood inventory which should be without compromising or diluting standards of safe blood transfusion.

 
  References Top

1.
Parker-Williams EJ. Autologous blood transfusion. Postgrad Dr 1989;11:52-6.  Back to cited text no. 1
    
2.
Kruskall MS. Autologous blood transfusion and related alternatives to allogenic transfusion. In: Hillyer CD, Silberstein LE, Ness PM, Anderson KC, Roback JD, editors. Blood Banking and Transfusion Medicine. 1 st ed. Philadelphia: Churchill Livingstone; 2003. p. 273-82.  Back to cited text no. 2
    
3.
Lockwood CD. Surgical treatment of Banti's disease. Surg Gynecol Obstet 1917;25:188.  Back to cited text no. 3
    
4.
Kanter MH, van Maanen D, Anders KH, Castro F, Mya WW, Clark K. Preoperative autologous blood donations before elective hysterectomy. JAMA 1996;276:798-801.  Back to cited text no. 4
    
5.
Yamamoto K, Imakiire A, Masaoka T, Shinmura K. Autologous blood transfusion in total hip arthroplasty. J Orthop Surg (Hong Kong) 2004;12:145-52.  Back to cited text no. 5
    
6.
Manchester, Transfusion SHOT, UK. Available from: http://www.shotuk.org. [Last accessed on 2013 Feb 22].  Back to cited text no. 6
    
7.
Hendrickson JE, Hillyer CD. Noninfectious serious hazards of transfusion. Anesth Analg 2009;108:759-69.  Back to cited text no. 7
    
8.
Saluja K, Marwaha N, Thakral B, Goni V, Sharma RR, Puri GD. Feasibility of pre-operative autologous blood donation in Indian patients with elective orthopaedic surgery. Indian J Med Res 2006;124:505-12.  Back to cited text no. 8
[PUBMED]  Medknow Journal  
9.
World Health Organisation, Blood Transfusion Service. Global Database on Blood Safety from 1998 to 1999. Geneva, WHO/BTS, Summary Report, 2001. Available from: http://www.who.co.in. [Last accessed on 2013 Feb 21].  Back to cited text no. 9
    
10.
Voluntary blood donation collection: Indian scenario. New Delhi: National AIDS Control Organisation, Ministry of Health and Family Welfare, Government of India; 2004. Available from: http://www.NBTC.com. [Last accessed on 2013 Feb 15].  Back to cited text no. 10
    
11.
Hatzidakis AM, Mendlick RM, McKillip T, Reddy RL, Garvin KL. Preoperative autologous donation for total joint arthroplasty. An analysis of risk factors for allogenic transfusion. J Bone Joint Surg Am 2000;82:89-100.  Back to cited text no. 11
    
12.
Goodnough LT, Rudnick S, Price TH, Ballas SK, Collins ML, Crowley JP, et al. Increased preoperative collection of autologous blood with recombinant human erythropoietin therapy. N Engl J Med 1989;321:1163-8.  Back to cited text no. 12
    
13.
Kruskall MS, Glazer EE, Leonard SS, Willson SC, Pacini DG, Donovan LM, et al. Utilization and effectiveness of a hospital autologous preoperative blood donor program. Transfusion 1986;26:335-40.  Back to cited text no. 13
    
14.
Healy JC, Frankforter SA, Graves BK, Reddy RL, Beck JR. Preoperative autologous blood donation in total-hip arthroplasty. A cost-effectiveness analysis. Arch Pathol Lab Med 1994;118:465-70.  Back to cited text no. 14
    
15.
Blumberg N, Kirkley SA, Heal JM. A cost analysis of autologous and allogeneic transfusions in hip-replacement surgery. Am J Surg 1996;171:324-30.  Back to cited text no. 15
    
16.
Goodnough LT, Shander A. Blood management. Arch Pathol Lab Med 2007;131:695-701.  Back to cited text no. 16
    
17.
U.S. Department of Health & Human Services, National Guideline Clearinghouse, Guidelines for policies on alternatives to allogenic bold transfusion.1.Predeposit autologous blood donation and transfusion. Guideline Summary NGC-6193. 10/1/12. Available from: http://www.ahrq.gov. [Last accessed on 2013 Feb 11].  Back to cited text no. 17
    
18.
National AIDS Control Organisation. Ministry of Health and Family Welfare, Government of India, New Delhi. Available from: http://www.NBTC.com. [Last accessed on 2013 Feb 12].  Back to cited text no. 18
    
19.
Mahasbtc-Autologous Blood Transfusion. Government of Maharashtra. Blood Transfusion Council. 10/1/12. Available from: http://www.mahasbtc.com/index.php?option=com_content&task. [Last accessed on 2013 Feb 23].  Back to cited text no. 19
    
20.
Heiss MM, Mempel W, Jauch KW, Delanoff C, Mayer G, Mempel M, et al. Beneficial effect of autologous blood transfusion on infectious complications after colorectal cancer surgery. Lancet 1993;342:1328-33.  Back to cited text no. 20
    
21.
Vanderlinde ES, Heal JM, Blumberg N. Autologous transfusion. BMJ 2002;324:772-5.  Back to cited text no. 21
    
22.
Billote DB, Glisson SN, Green D, Wixson RL. A prospective, randomized study of preoperative autologous donation for hip replacement surgery. J Bone Joint Surg Am 2002;84-A: 1299-304.  Back to cited text no. 22
    
23.
Unused Autologous Blood-Why Is It Not Made Available for General Use? Transfusion of Autologous Blood Components. Available from: http://www.bloodbook.com/autolog-3.html. [Last accessed on 2013 Feb 05].  Back to cited text no. 23
    
24.
Giri PA, Yadav S, Parhar GS, Phalke DB. Frequency of ABO and rhesus blood groups: A study from a rural tertiary care. Int J Biol Med Res 2011;2:988-90.  Back to cited text no. 24
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

Top
   
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
Conclusion
References
Article Tables

 Article Access Statistics
    Viewed1675    
    Printed9    
    Emailed1    
    PDF Downloaded148    
    Comments [Add]    

Recommend this journal