Liberal Transfusions Linked to Increased Morbidity Following Spine Surgery

The impact of more liberal use of transfusions on patient outcomes in spine surgery was not investigated prior to this study. Comments by senior author Daniel M. Sciubba, MD, FAANS.

While liberal transfusion of blood during and after spine surgery is often thought to be beneficial for patients, new findings suggest that this practice is associated with increased perioperative morbidity and longer in-hospital stays compared with use of more restrictive triggers for transfusion. The findings are based on a retrospective analysis of data from a single institution published in the September issue of The Spine Journal.

blood storage

“As a complex spine surgeon who performs large operations, there is a general cultural feeling that patients should receive as much blood as needed during surgery and post-operatively,” explained senior author Daniel M. Sciubba, MD, FAANS, Director of Spine Tumor and Spine Deformity Surgery and Professor of Neurosurgery at The Johns Hopkins Hospital in Baltimore, MD. “We don’t want the patient to bottom out during surgery. In addition, if patients’ hemoglobin (Hb) levels are low post-operatively, they don’t heal as well, are fatigued, and need a lot of nutritional support.”

However, the impact of more liberal use of transfusions on patient outcomes in spine surgery was not investigated prior to this study, Dr. Sciubba and colleagues noted in the paper. Findings from randomized controlled studies in hip and cardiac surgery have shown similar or improved outcomes with restrictive versus liberal transfusion triggers, according to the investigators.

Study Methods
The researchers examined 2008-2015 data from 6,931 patients who underwent the following procedures at The Johns Hopkins Hospital between 2008 and 2015: atlantoaxial fusion, anterior cervical fusion, posterior cervical fusion, anterior lumbar fusion, posterior lumbar fusion, lateral lumbar fusion, other procedures, and tumor-related surgeries.

The primary outcome measure was morbidity, which was a composite of the following outcomes: infection, thrombotic event, kidney injury, respiratory event, and ischemic event. A whole hospital nadir Hb between 8 and 10 g/dL was used to define a liberal transfusion trigger based on previous research showing that this level is in the intermediate zone where transfusions may be unnecessary in some patients, the researchers explained in the study.

Approximately half of the 2,470 patients (n=1,258; 51%) with a whole hospital stay nadir Hb between 8 and 10 g/dL received a blood transfusion. In this group, the risk for complications was significantly higher among transfused patients than among non-transfused patients (11.5% vs 6.1%; P<0.001). In addition, the median length of stay was significantly longer for transfused patients than non-transfused patients (6 vs 4 days; P<0.001).

Twofold Higher Risk for Morbidity Found With Liberal Blood Transfusion
Multivariate analysis showed that patients with a whole hospital nadir Hb of 8 to 10 g/dL who received blood transfusions had a significantly higher prevalence of perioperative morbidity (11.5%; odds ratio=2.11; P<.0001). This analysis controlled for a variety of potentially confounding factors including age, gender, race, American Society of Anesthesiologists class, Charlson Comorbidity Index score, estimated blood loss, baseline Hb value, and surgery type.

In addition, reliance on liberal transfusion triggers resulted in an estimated annual cost of $202,675 to $700,151 per year, the researchers found.

Dr. Sciubba told SpineUniverse that the more factors the researchers controlled for the more compelling the data became.

One of the potential reasons for the increased risk of morbidity with liberal transfusion triggers is that “donated red blood cells develop the so-called ‘RBC storage lesion’ the longer they sit in storage,” Dr. Sciubba said. “Potential mechanisms include a decrease in 2,3-diphosphoglycerate and nitric oxide concentrations, loss of cell membrane deformability, and increased endothelial adherence and extravascular hemolysis.”

Dr. Sciubba added that his team has a study in press describing that spine surgery patients have more post-operative complications when transfused with blood stored longer versus shorter.

Findings May Change Clinical Practice
The findings “may change how we operate,” Dr. Sciubba said, adding that this research has changed his practice. While decisions need to be made on a case by case basis, he may hold back on use of transfusions for borderline patients with Hb levels (eg, 9.9 g/dL) who might be able to raise their Hb following surgery with iron-rich foods.

“It is those borderline patients who might be better with a slightly lower Hb with close follow-up afterwards,” Dr. Sciubba said. However, he noted that surgeons should not wait to transfuse patients who are rapidly losing blood or who have a history of heart disease, for example.

In addition, the findings may have cost-savings implications for hospitals, Dr. Sciubba explained. “Not only is use of a liberal transfusion trigger a potential cause of complications, it might be a driver of expense,” he said.

Dr. Sciubba is a consultant for Medtronic, Depuy-Synthes, Stryker, NuVasive, K2M.

Updated on: 10/03/17
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