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ORIGINAL RESEARCH |
From the *Department of Hematology, University of Toronto, and the Departments of Maternal Fetal Medicine, and Clinical Pathology, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada.
Address reprint requests to: Dr. Jeannie Callum, Sunnybrook and Women's College Health Sciences Centre, Room B-204, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada; e-mail: jeannie.callum{at}sw.ca.
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ABSTRACT |
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 ABSTRACT MATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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METHODS: We reviewed all RBC transfusions given to peripartum inpatients at Sunnybrook and Women's College Health Sciences Centre in Toronto, Ontario, Canada between April 1994 and July 2002. Appropriateness of RBC transfusion was ascertained using current hospital transfusion guidelines.
RESULTS: We identified 33,795 obstetrics-related admissions. In 218 admissions (0.65% of all admissions), an RBC transfusion was given to 216 women. There were 83 vaginal deliveries, 94 deliveries by cesarean, and 42 operations (for ectopic pregnancies or dilatation and curettage). A total of 779 RBC units were transfused (median, 2 units per woman; range, 1–32), most commonly for postpartum bleeding (34% of cases). There were 16 adverse events from transfusion recorded. According to guidelines, 248 of the transfused RBC units (32%) were not appropriate. In addition, in 24 patients (11%) the mean corpuscular volume on admission to the hospital for delivery was less than or equal to 80 fL.
CONCLUSION: A significant proportion of RBC transfusions given to peripartum women are inappropriate. Educational programs that promote adherence to transfusion guidelines might help reduce exposure to RBC transfusion. Aggressive oral and intravenous iron therapy might have prevented transfusion in 11% of the women in the cohort who were possibly iron deficient.
As a general rule, RBC transfusions should be given only when absolutely necessary6,7 to minimize the risks of exposure to allogeneic blood products and to decrease health care costs. The need for transfusion of RBC should be based on clinical signs and symptoms of anemia, rather than on hemoglobin levels or expected future blood loss.6–8 To encourage this principle, several national guidelines, based on thorough reviews of the transfusion literature, have been published.6–8 However, despite this, several studies have shown that a significant proportion of transfusions are not in accordance with guidelines.9–16 Although some of these studies have included patients admitted to an obstetric or gynecologic service,9–13 this study evaluates RBC transfusions in this specific patient population.
We conducted a retrospective review of all peripartum women receiving an RBC transfusion at our institution to evaluate the reasons for, and appropriateness of, RBC transfusions given to women around the time of delivery or termination of pregnancy.
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MATERIALS AND METHODS |
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Clinical and relevant obstetric and laboratory data were recorded for all patients. The number of RBC units transfused, reasons given for the transfusion, and possible adverse effects of the transfusions were collected. Admission and pretransfusion laboratory values (hemoglobin, mean corpuscular volume), vital signs, and clinical assessments of the patient, along with any comments in the chart relating to the blood transfusion, were noted.
The appropriateness of RBC transfusion was ascertained using current transfusion guidelines approved by the hospital's transfusion committee. These guidelines were created as practical tool to reduce inappropriate transfusions, and were developed with input from recently published guidelines for the bleeding6,7 and nonbleeding8 patient, incorporating both symptoms of anemia and absolute hemoglobin levels.
For bleeding patients, the guidelines recommend maintaining hemoglobin levels above 70 g/L, unless there is evidence for impaired pulmonary function, unstable angina or acute myocardial infarction, in which cases a higher hemoglobin level is appropriate. In nonbleeding patients, the guidelines state that an RBC transfusion is likely to be appropriate for a hemoglobin less than 70 g/L, may be appropriate for hemoglobin levels of 70–100 g/L if there are signs or symptoms of impaired tissue oxygen delivery, and unlikely to be appropriate when the hemoglobin is greater than 100 g/L. In addition, the situation should be reassessed after each unit of RBC in a nonurgent setting. When the indication for transfusion was unclear, or where the clinical situation precluded the obtaining of hemoglobin levels because of massive bleeding, the transfusion was classified as being appropriate.
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RESULTS |
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In 218 admissions (0.65% of all admissions), a transfusion was given to a total of 216 women (2 women were transfused during separate pregnancies). The pregnancies ended in 83 vaginal deliveries, 94 deliveries by cesarean, and 42 operations for pregnancy-related complications (eg, ectopic pregnancy, dilatation and curettage). One woman gave birth to twins, one by vaginal delivery and the other by cesarean. The yearly transfusion rates varied from 0.37% of all obstetrics-related admissions in 1994 to 0.89% in 1996.
The median age of women at transfusion was 34 years (range, 19–45). A total of 779 units of RBC were transfused (median, 2 units per woman; range, 1–32). A total of 130 women were given 1 or 2 units, 47 needed 3 or 4 units, 27 received 5–9 units, and 12 women received 10 or more units. Fifty-two units were transfused before delivery or operation, 148 units were transfused during delivery or intraoperatively, and 579 units were given postpartum or postoperatively. The most common reason for transfusion was postpartum bleeding (74 cases); other reasons are listed in Table 1.
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Using our current hospital transfusion guidelines, 248 units (31.8%) of all RBC transfusions were deemed not appropriate. In 37 cases (17% of women transfused), no transfused units would have been required had the guidelines been followed correctly. Transfusions were considered inappropriate in 36 of 52 units (69%) given before delivery or operation, in 35 of 148 units (24%) given during delivery or intraoperatively, and in 177 of 579 units (31%) given postpartum or postoperatively.
Of the 248 inappropriate units, 43 (17%) were classified as inappropriate due to patients receiving an excessive amount of RBC units to alleviate symptomatic anemia ("overtransfusion"); 91 units (37%) were inappropriately transfused to patients who, despite ongoing bleeding, had stable vital signs and a hemoglobin above 70 g/L; and 114 units (46%) were considered inappropriate because they were transfused to a patient with asymptomatic anemia.
When analyzed by the year of admission, the overall rates of inappropriate transfusion ranged from 20% in 2000 to 46% in 1997, without any clear trend over the study period. There were 16 transfusion-related adverse reactions out of 779 transfused units (2% of all units transfused) documented in the patients’ charts, all of a minor nature (febrile reactions, urticaria, or volume overload).
In 24 patients (11%), the mean corpuscular volume upon admission to the hospital was less than or equal to 80 fL. Of those 24 women, 5 women had a ferritin level less than or equal to 30 µg/L, 2 were known to have thalassemia, and the rest had no further evaluations performed during their inpatient admission. Excluding the two known cases of thalassemia, the remaining 22 women with low mean corpuscular volumes received 85 RBC units.
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DISCUSSION |
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Although several studies have included obstetrical patients, they did not specifically focus on peripartum women. Early reports from the 1960s found that between 27% and 67% of women received an unnecessary RBC transfusion.9–11 More recently, using a hemoglobin level of 70 g/L as a trigger for transfusion, Ross et al (Ross A, Malkoutzis E. Blood transfusion practice in obstetric and gynaecological anaesthesia [abstract]. Anaesth Intensive Care 1995;23:645) found that 62% of transfusions associated with cesarean deliveries were inappropriate; however, only 13 patients were transfused in that study. Rubin et al12 included 67 obstetrics and gynecology patients in their audit and found that at least 15% of transfusions were not warranted. Marti-Carvajal et al13 included 173 obstetric patients in their study of RBC transfusions at their hospital and found that 51% of units were unnecessary. In contrast, Brien et al19 retrospectively reviewed RBC transfusions at one tertiary site and included 85 obstetric patients; these investigators found that just 5% of transfusions were not appropriate. This large disparity in numbers between the different studies reflects different criteria used to judge the appropriateness of transfusions,20 differences in study design and sample size, the period of data collection, and patient population.21
Our study of obstetric patients focuses on the peripartum and confirms that a significant percentage of RBC transfusions in this setting are inappropriate. In addition, we found that the majority of women were transfused after delivery or termination of pregnancy, that postpartum hemorrhage was the most common reason for transfusion, and that the most common error was transfusing a patient based only on a low hemoglobin value despite the absence of symptoms. This information suggests that the most likely time for a pregnant woman to receive an RBC transfusion is actually in the postpartum setting, when hemoglobin values are likely to be at their lowest.22
Unlike other studies that found that the frequency of transfusion and the rate of inappropriate transfusion decreased with time,2,23 in this study, no such trends were apparent. Thus, the publication of national guidelines in 1997, which advocate avoiding transfusion based solely on hemoglobin levels,6 appear to have made little impact on the transfusion practices at our institution.
Several different interventions to decrease the proportion of unnecessary transfusions have been proposed in the literature. Educational approaches including lectures aimed at the responsible physician,24 scheduling formal conferences,25 implementing algorithms,17,26 and reviewing all orders for blood products27 reduce transfusion rates when implemented properly. However, none of these approaches have been used to target obstetric patients. Given the high rate of inappropriate transfusions in our study, the obstetric setting may be a good target for some of these strategies.
In the United States, 12% of women between the ages of 20 and 50 years are iron deficient,28 with as much as 37% of pregnant women becoming frankly anemic from iron deficiency by the third trimester.29 In other countries, estimates of iron deficiency during pregnancy have ranged from 13.6%30 to 54%.31 Iron supplementation during pregnancy is feasible, safe, and beneficial.32 For women who are intolerant of or refractory to oral iron, intravenous iron complexed with either ferrous sodium gluconate or sucrose is well-tolerated, easy to administer, and effective.33 In this study, although mean corpuscular volume values during pregnancy were not known, they were low and suggestive of iron deficiency in 11% of patients upon hospital admission. It is possible that had iron deficiency been corrected earlier, the transfusion of up to 85 units of RBCs might have been prevented.
Because this study was done retrospectively, it should be interpreted with some caution. It is possible that some patients who received transfusions classified as being not required may have had signs or symptoms of anemia not recorded in the chart, thus falsely increasing the percentage of unnecessary transfusions. To minimize this, we made every effort to review all available information in the charts, and where unclear, the transfusion was considered appropriate. In addition, in the intraoperative setting, transfusions were classified as appropriate unless there was no ongoing bleeding, normal vital signs, and suitable hemoglobin levels. In doing so, this study may have even underestimated the amount of inappropriate transfusions.
We conclude that a significant percentage of RBC transfusions at our institution are unnecessary. Interventions that promote adherence to transfusion guidelines along with the proper use of iron supplementation, including both oral and intravenous preparations, might help reduce needless exposure to RBC transfusion.
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Footnotes |
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doi:10.1097/01.AOG.0000142710.16254.21
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REFERENCES |
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2. Klapholz H. Blood transfusion in contemporary obstetric practice. Obstet Gynecol 1990;75:940–3.
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