Original Research

Anemia Versus Transfusion: Does Blood Conservation Increase the Risk of Complications?

Am J Orthop. 2015 January;44(1):E11-E16

References

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Results

The charts of 104 patients were reviewed and included in this analysis. Sixty-two patients (60%) had received a transfusion; 42 (40%) had not. Before first transfusion, 21 (34%) of the 62 transfused patients had Hgb levels under 7.0 g/dL, and the other 41 (66%) had Hgb levels of 7.0 g/dL or higher. Of the 42 nontransfused patients, 8 (19%) had lowest Hgb levels under 7.0 g/dL, and the other 34 (81%) had Hgb levels of 7.0 g/dL or higher (Table 1).

The transfused patients, considering all levels of anemia, had a mean ISS of 16.1 (range, 1-45), a mean of 2.0 operations (range, 1-6), a mean hospital stay of 18 days (range, 1-73 days), and a mean age of 34 years (range, 18-50 years). The nontransfused patients, considering all levels of anemia, had a mean ISS of 14.1 (range, 4-43), a mean of 1.4 operations (range, 1-5), a mean hospital stay of 10 days (range, 1-42 days), and a mean age of 33 years (range, 18-50 years). In the transfusion group, the mean number of transfused pRBC units was 6.9 (range, 1-31), or 7.8 units for patients with Hgb levels under 7 g/dL and 6.4 units for patients with Hgb levels of 7 g/dL or higher. At 1-year follow-up, complications were observed in 41 (66%) of the 62 transfused patients and in 17 (40%) of the 42 nontransfused patients (Table 1). The different types of complications seen in each group are listed in Table 2.

Statistical Analysis

Patients were divided into 2 groups by Hgb level—under 7.0 g/dL and 7.0 g/dL or higher—and then by whether they received pRBC transfusion. In addition, which patients had a complication over a 1-year period were identified.

For each group, we calculated sample size, number of complications, complication rate, and 95% CI for proportions. For transfused patients with Hgb level of 7.0 g/dL or higher, the complication rate was 71% (29/41). For nontransfused patients with Hgb of 7.0 g/dL or higher, the complication rate was 41% (14/34). Similarly, for transfused patients with Hgb under 7.0 g/dL, the complication rate was 57% (12/21). Last, for nontransfused patients with Hgb under 7.0 g/dL, the complication rate was 38% (3/8) (Table 3).

Transfused patients had a significantly higher risk of complication (OR, 3.1; 95% CI, 1.4-7.1; P < .01). Severity of anemia was not found to be independently associated with increased risk of complication (OR, 0.6; 95% CI, 0.3-1.6; P = .33) (Table 4). The interaction term was removed and eliminated from further analysis, as it was not found to be significant (P = .45).

Furthermore, the possibility of confounding variables (eg, age, sex, ISS, number of surgeries performed) was considered by including them in the model one at a time. From these logistic regression models, which included whether patients were transfused and level of anemia, an increased risk of complication (OR, 1.8; 95% CI, 1.1-2.9; P = .02) was found for each additional surgery, while receiving transfusion remained statistically significant (OR, 2.5; 95% CI, 1.0-5.8; P < .04). Age, sex, and ISS were not shown to be significantly associated with an increased complication rate (Ps = .71, .32, and .13, respectively).

We performed a subanalysis of the transfused patients to determine the impact of number of units transfused on complication rate. Each additional unit of pRBCs transfused increased the risk of complication, indicating a dose-dependent response (OR, 1.3; 95% CI, 1.04-1.51; P = .02).

Discussion

Transfusion is a generally accepted and common intervention both in the intensive care unit and in the perioperative period. However, there is little evidence to support routine transfusion of asymptomatic orthopedic trauma patients who are no longer within the initial resuscitative period after trauma. Nevertheless, the practice is routinely done based on expert opinion (level 5 evidence). The anemia protocol for our orthopedic trauma service routinely allowed the Hgb levels of asymptomatic healthy patients to drop to under 7.0 g/dL without transfusion; when other services were consulted or were primary, however, these asymptomatic patients were still routinely transfused based on practitioners’ practice patterns and anecdotal experiences.

In hemodynamically unstable patients, there is no acceptable substitute for blood transfusion. Blood replacement remains essential in the case of acute hemorrhage. However, the complications associated with transfusion should lead us to avoid, or at least minimize, unnecessary transfusion in young asymptomatic patients who are not actively bleeding in the postresuscitative period. In our study, we did not seek causation of increased complications with transfusion but assessed whether the risk of anemia outweighed the risk of transfusion in young, healthy, asymptomatic trauma patients who were no longer in the initial resuscitation period.