Maximum surgical blood ordering schedule in a tertiary trauma center in northern India: A proposal.

CONTEXT: Over ordering of blood is a common practice in elective surgical practice. Considerable time and effort is spent on cross-matching for each patient undergoing a surgical procedure. AIMS: The aim of this study was to compile and review the blood utilization for two key departments (Neurosurgery and Surgery) in a level 1 trauma center. A secondary objective was to formulate a rational blood ordering practice for elective procedures for these departments.
MATERIALS AND METHODS: Analysis of prospectively compiled blood bank records of the patients undergoing elective surgical, neurosurgical procedures was carried out between April 2007 and March 2009. Indices such as the cross-matched/transfused ratio (C/T ratio), transfusion index and transfusion probability were calculated. The number of red cell units required for each procedure was calculated using the equation proposed by Nuttall et al, using preoperative hemoglobin and postoperative hemoglobin for each elective surgical procedure.
RESULTS: There were 252 surgery patients (age range: 2-80 years) in the study. One thousand and eighty-eight units of blood were cross-matched, 432 were transfused (CT ratio 2.5). 44.0% patients did not require transfusion during entire hospital stay. Three (50%) elective procedures had CT ratio >2.5and 4 (66.6%) elective procedures had TI <0.5. There were 200 neurosurgery patients (age range: 2-62 years) in the study. Total 717 units of blood were cross-matched and 161 transfused (CT ratio 4.5). Nine elective procedures had CT ratio >2.5, with five of them exceeding 4. In procedures like spinal instrumentation the CT ratio was <2.5 and 10 (90.9%) of elective procedures had TI <0.5.
CONCLUSIONS: In this study 40% and 22% of cross-matched blood was being utilized for elective general surgery and neurosurgical procedures, respectively. The calculated required blood units for all elective Trauma surgery procedures were more than 2 units. The calculated required blood units were less than 0.5 units in four of the 11 neurosurgical procedures, and hence only one unit should be arranged for them. It is crucial for every institutional blood bank to formulate a blood ordering schedule. Regular auditing and periodic feedbacks are also vital to improve the blood utilization practices.

INTRODUCTION

Ordering of blood is a common practice in elective surgical procedures. The preoperative request for blood units is often based on worst case assumptions, with potential for exhaustion of the blood bank resources. The time and effort consumed in cross-matching for each patient undergoing a surgical procedure is substantial, most of which is actually not utilized for transfusion. Gross over ordering is evidently seen in a distinctly high blood cross-matched to transfused ratio. Any blood bag, which is extracted from the blood bank inventory for cross-matching, becomes unavailable for other patient′s. Once cross-matched the blood bag is held in reserve, ensuing inventory problems for blood banks, loss of shelf life and wastage of blood unit.[1-3] Consequently if unnecessary blood orders can be reasonably waived, it will reduce both workload and financial expenditure. A review of the surgical blood ordering practice is, therefore, mandatory.[4]

A blood ordering schedule serves as a guideline to anticipated normal blood usage for elective surgical procedures, with the intention to relate the ordering of blood to the likely hood that a transfusion will be required.[3] A maximum surgical blood ordering schedule (MSBOS) is a list of common elective surgical procedures performed, along with the maximum number of blood units being cross-matched preoperatively for each procedure.[56] The principle of which is to decrease the quantity of blood being cross-matched, by assigning each elective surgical procedure a tariff of transfusion. A MSBOS is designed to order adequate blood units for up to 90% of the patients undergoing an elective surgical procedure. The ratio of the number of units’ cross-matched red cells for a given surgical procedure to the number of units actually transfused should not exceed 2:1.[78] Although MSBOS has succeeded in propelling the efficiency of blood ordering system,[7] it is ineffectual in accounting for individual differences in transfusion requirements between different patients undergoing the same surgical procedure. Also, MSBOS is not capable of identifying over transfusion, nor does it impact on institutional variation in transfusion practices

Surgical blood ordering schedule (SBOS) is a comprehensive MSBOS, which includes patient and surgery specific variables such as preoperative and postoperative hemoglobin levels of the patient and amount of surgical blood loss during each surgical procedure.[78] It also enables the identification of procedures that can be accommodated by the group and save policy, reducing superfluous compatibility testing and wastage due to outdating.[3] Such an SBOS allows the surgical teams, to develop unique local transfusion system, and to set its own minimum transfusion levels for fit and unfit patients.

This study was carried out to compile and review the blood utilization in elective procedures in trauma surgery and neurosurgery departments in a tertiary care trauma center. A secondary objective was to formulate and recommend a rational blood ordering practice, based on the outcome of the study.

We have previously designed a SBOS for elective orthopedic procedures.[1] The present study was undertaken as a continuation to the previous study, to formulate a SBOS for the all trauma surgery departments (Orthopedic, General surgery and Neurosurgery) in a trauma care setup.

We aim at determining the effectiveness of blood ordering system for surgical procedures in a tertiary hospital and also to accentuate the need for every hospital to develop a SBOS.

MATERIALS AND METHODS

Analysis of prospectively compiled blood bank records of the patients undergoing elective surgical and neurosurgical procedures was undertaken. The study was carried out between April 2007 and March 2009. Case and blood bank records of all the patients undergoing elective surgical and neurosurgical procedures were collected on an excel spread sheet. Patients who underwent massive transfusion were excluded from the study. Massive transfusion in a trauma setting has been defined in several ways. Our definition of massive transfusion includes those patients who received 10 units or more of packed RBCs in 24 hours. Patient and surgical parameters include age and gender, type of surgical procedure, pre and postoperative hemoglobin levels, estimated blood loss for each surgical procedure and predicted fall in hemoglobin. Routine transfusion parameters such as number of units transfused, cross-matched and returned were also tabulated. Indices such as the cross-matched/transfused ratio (C/T ratio), transfusion probability (%T) and transfusion index (TI), were then calculated.

The use of cross-match to transfusion ratio (C/T ratio) was first recommended by Boral Henry in 1975.[5] Ideally, this ratio should be 1.0 but a ratio of 2.5 and below was suggested to be indicative of efficient blood usage.[3]

The probability of a transfusion (%T) for a given procedure was suggested by Mead et al in 1980.[9] A value of 50% and above has been suggested as appropriate[3]

Transfusion index (TI) signifies the appropriateness of numbers of unit's cross-matched. A value of 0.5 or more is indicative of efficient blood usage.[35]

We calculated a blood ordering schedule for six surgical and eleven neurosurgical procedures using surgical blood ordering equation (SBOE). In an earlier study by Subramanian et al,[1] a blood ordering schedule for elective orthopedic surgeries was drafted using the same SBOE.

Using basic physiological principles many SBOEs can be derived; however, we have employed the equation proposed by Nuttall et al,[10] to calculate the number of red cell units required for each procedure.

The predicted hemoglobin fall is calculated based on the amount of blood loss during each surgical procedure assuming that 1 unit of blood lost will decrease the patient's hemoglobin by 1 g/dl. The postoperative hemoglobin is taken at 24-h postsurgery. The difference in the mean preoperative and mean postoperative hemoglobin levels of the patient for each procedure gives the actual hemoglobin loss for any surgical procedure.[1]

RESULTS

Trauma surgery

A total of 252 patients who underwent elective procedures in trauma surgery in our trauma center, were included in the study. There were 204 males (81%) and 48 females (19%). The median age was 26 years (2-80 years). Out of the 1088 units of blood cross-matched, only 432 (40%) were transfused. 60% of the total cross-matched units were not transfused. One hundred and eleven (44.04%) of the 252 patients did not require transfusion during entire hospital stay. The number of patients and blood units cross matched and transfused is tabulated below Table 1.

Table 1

Blood cross-match and transfusion patterns for different elective trauma surgeries

Four of the six elective surgery procedures, i.e., laparotomy, vascular injuries amputation and plastic surgery had CT ratio higher than 2.5, with one of them, namely vascular injuries up to 5. In procedures like extremity soft tissue injuries, and thoracotomy the CT ratio was less than 2.5. The probability the patient would undergo transfusion (%T) was <50 in fasciomaxillary and neck procedures. Four out of six (71.42%) elective procedures had TI <0.5 [Table 2].

Table 2

Blood utilization for different elective trauma surgeries

Neurosurgery

A total of 200 patients who underwent 11 elective procedures in neurosurgery were also included in the study. The median age was 27 years (2-62 years). There were 170 males (85%) and 30 females (15%). Total 717 units of blood were cross-matched and only 161(22%) transfused. Seventy-eight percent of the total cross-matched units were not transfused. One hundred and forty (70%) patients did not require transfusion during their hospital stay [Table 1].

Nine of the 11 elective neurosurgery procedures had CT ratio higher than 2.5, with five of them exceeding 4, namely trephine and EDH evacuation, decompressive craniectomy, cranioplasty, VP shunt and brachial plexus repair and exceeding 7 for VP shunt. In procedures like spinal instrumentation the CT ratio was less than 2.5. The transfusion probability for these procedures was <50%, except for cervical discectomy and plating. Ten out of 11 (90.90%) elective procedures had TI <0.5. For spinal instrumentation, TI >0.5 was observed [Table 2].

The minimum, average and maximum blood loss for each surgical procedure was estimated by the surgeons and neurosurgeons based on MOP counts and the amount of suction fluid [Table 3]. This excludes the amount of fluid infused at the time of surgery. The corresponding hemoglobin loss was predicted based on the assumption that 1 unit of blood loss decreases the hemoglobin by 1 g/dl. The mean preoperative hemoglobin in the study group for general surgery was 10.3±2.4 g/dl (mean±SD) and mean postoperative hemoglobin was 10.2±1.9 g/dl (mean±SD). In the study group for neurosurgery the mean preoperative hemoglobin was 11.4±2.1 g/dl (mean±SD) and mean postoperative was 11.3±2.2 g/dl (mean±SD).

Table 3

Blood loss during different elective trauma surgeries

The reduction in hemoglobin in the present study is the result of the reduction in hemoglobin prior to and after operation in the subjects under study. Their preoperative hemoglobin was stabilized with blood transfusions prior to the planned procedure if it was low. On the other hand, blood ordered preoperatively before the elective procedure was in excess of the actual need as shown by the blood loss during each surgical procedure [Table 4]. Similarly, the postoperative transfusions were given 24 h after surgery when required

Table 4

Hemoglobin loss - Actual and predicted with the surgical blood ordering schedule for different elective trauma surgeries

The actual hemoglobin fall [Figures 1–3] was much lower in most of the procedures than that predicted from the amount of surgical blood loss. The SBOS was sketched out based on the SBOE. When the number of units calculated is less than 0.5 units, a group and save policy is advocated. When it is more than 0.5 units, the number of RBC units is rounded off to the nearest integer. The actual, predicted hemoglobin loss and the SBOS were tabulated in Table 4.

Figure 1

Actual hemoglobin fall in general trauma surgeries

Figure 3

Actual hemoglobin fall in trauma orthopedic surgeries

Actual hemoglobin fall in trauma neurosurgeries

DISCUSSION

Blood and blood components are crucial in patient care but are in limited supply and have significant associated risks and costs. Blood transfusion no doubt plays a major role in the resuscitation and management of surgical patients, but surgeons most of the times overestimate the anticipated blood loss. Over-ordering of blood is a common practice in surgeries. Elective surgery is a major part of this demand for blood and blood products as the preoperative blood order goes beyond the real need. The preoperative assessment of blood requirements is often an over assumption, which results in important problems in a blood bank management about blood aging and outdating, availability of particular groups and phenotypes, unnecessary laboratory work and extra-costs. Unnecessary cross-matching of blood is expensive and can result in unwarranted transfusion with needless exposure of patients to the risks of transfusion therapy,[11] such as human immunodeficiency virus (HIV) and hepatitis B and C.

The estimated risks of transfusion have dramatically decreased over the recent years as increased test sensitivity has reduced infectious window periods.[19] Incorporation of advance blood screening techniques has resulted in the enhancement of the quality of the blood products. Hence it is essential that the usage of blood and blood products be rationalized and they are set aside for crisis situations.

Proper placement of blood requests according to a designed schedule most often wards off the consequences of capricious ordering of blood. This requires streamlining blood ordering schedule keeping in view the blood bank supplies and resources both in technician time and reagents. The MSBOS is used to promote autoreduction of blood request, thereby, increasing efficient blood ordering practice for surgical patients. MSBOS has been in use since 1975[7] and has been undergoing periodic modifications since the time of implementation. The initial formulation of MSBOS was done using Mead's criterion.[12-14] According to this criterion, the number of RBCs calculated was one and half times the transfusion index for each surgical procedure.[1]

Mead's criterion was used by Vibhute et al,[2] to establish a MSBOS for elective surgical procedures.

Mead's criteria: MSBOS=1.5× transfusion index

They evaluated the blood ordering and transfusion practices in 500 elective general surgical procedures. Using indices same as our study, blood ordering pattern was changed in the next 150 patients. Using indices same as our study, blood ordering pattern was changed in the next 150 patients. Out of 1145 units of blood cross-matched for the first 500 patients only 265 were transfused with nonutilization of 76.86% of ordered blood. With the help of the indices the wastage was reduced in next 150 patients and improved the utilization of blood.

In a similar study by Bhutia et al,[12] the blood evaluation and transfusion practices for 680 patients undergoing 21 different surgical procedures were evaluated and MSBOS formulated. However, it does not take into consideration the individual differences in transfusion needs between different patients undergoing the same surgery.

SBOS is an extension of MSBOS incorporating patient and surgical variables. Many risk factors have been assessed and found to be useful in predicting the blood transfusion.[1516] Some of them include low preoperative hemoglobin/hematocrit, short stature, female sex, availability of preoperative autologous blood donation, surgical blood loss and the type of surgery.[1]

A similar study[1] conducted in 2008, in the same unit resulted in the introduction of the local SBOS and the group and save policy for elective orthopedic procedure instead of a full cross-match. This paper is an augmentation of the study conducted earlier; we attempted to formulate a SBOS for elective general surgery and neurosurgery in trauma patients.

A review of preoperative blood orders has identified certain surgical procedures with insignificant blood loss and low transfusion probability, for which preoperative blood orders may be safely disregarded in order to reduce unnecessary laboratory workload while not jeopardizing patient safety.[4]

In the present study, a SBOS was formulated, based on the SOBE proposed by Nuttall et al.[10] The number of RBC units required is calculated incorporating patient-specific factors, such as the mean pre and postoperative hemoglobin levels of the patient and the amount of surgical blood loss predicted by the surgeons. The amount of blood loss was predicted based on the surgical blood loss during each procedure.

SBOE's were used in many studies,[1617] comparing the SBOE with the MSBOS. SBOS was observed to reduce the C:T ratio. However, prospective studies using this SBOE are required to study the efficiency of the blood ordering system in a trauma setup.

The notion of “group and save” has been in utilized since many years and many authors have shown that merits outweigh the alleged demerits.[1819] In the present study, when the number of units calculated for any surgery is less than 0.5 units, a group and save policy would be ideal. In this group and save policy, no presurgical cross-match would be done; instead grouping followed by screening for antibody is performed. In this study, group and save policy was recommended in none of the elective surgical procedures, and in four of the 11 elective neurosurgical procedures. Also only two of the 11 elective neurosurgical procedures required 1 unit of packed blood. Ten units of packed blood were required for decompressive craniectomy and trephine and EDH evacuation procedures.

Effectiveness of type and screen, in preventing incompatible transfusion, is observed due to the high efficacy of antibody screening in the detection of potentially clinically significant antibodies.

The system of SBOS allows for flexibility in the sense that should an antibody screen results be positive, antigen-negative, cross-matched blood must be made readily available. These blood ordering schedules are subject to approval by both the hospital transfusion committee and the clinicians. The efficiency of any blood ordering schedule implementation would require a similar audit after a minimum period of 6 months.[1]

A sufficient number of patients were not available for surgeries, such as Burr hole, cranioplasty, cervical discectomy and plating (n<5), which may have biased our final result in making the blood ordering schedule. However, as an initial measure it would prove to cut down unnecessary costs of reagents, resources, and the workload of blood bank personnel. Prospective studies would be required to find the efficiency of such SBOE's in other elective procedures. Also, for purposes of ease and simplicity we chose to employ the SBOE in the present study. Other factors, such as low weight, short stature, which may predict the risk of allogenic transfusion, were not taken in to account in this SBOE.

CONCLUSIONS

We had 40% and 22% of cross-matched blood being utilized for elective general surgery and neurosurgical procedures, respectively. In the present study the calculated required blood units for all elective surgical procedures were more than 2 units. Therefore, for procedures like thoracotomy 3 and plastic surgery 2 units, for laprotomy 7 units of blood should be arranged.

The calculated required blood units were less than 0.5 units in 4 of the 11 neurosurgical procedures, and hence only one unit should be arranged for patients undergoing elective cervical discectomy, VP shunt, percutaneous instrumentation and Burr hole. For patients undergoing spinal instrumentation and decompressive craniotomy 8-10 units of blood should be arranged prior to the procedure.

In order to relegate unnecessary cross-matching, blood ordering schedule catering to surgeon and patient requirements is essential. It is crucial for every institutional blood bank to formulate a blood ordering schedule, and the clinicians to take the initiative to order blood for the scheduled procedures in accordance with the devised SBOS for appropriate usage of blood resources. Regular auditing and periodic feedbacks are also vital to improve the blood utilization practices.