Jack O. Wasey

Risk‐adjusted clinical outcomes in patients enrolled in a bloodless program

Although clinical outcomes have been reported for patients who do not accept allogeneic blood transfusion (ABT), many previous studies lack a control group, fail to use risk adjustment, and focus exclusively on cardiac surgery.

Impaired Red Blood Cell Deformability After Transfusion of Stored Allogeneic Blood but not Autologous Salvaged Blood in Cardiac Surgery Patients

BACKGROUND:Both cardiopulmonary bypass (CPB) and red blood cell (RBC) storage are associated with detrimental changes in RBC structure and function that may adversely affect tissue oxygen delivery. We tested the hypothesis that in cardiac surgery patients, RBC deformability and aggregation are minimally affected by CPB with autologous salvaged blood alone but are negatively affected by the addition of stored allogeneic blood. METHODS:In this prospective cohort study, 32 patients undergoing cardiac surgery with CPB were divided into 3 groups by transfusion status: autologous salvaged RBCs alone (Auto; n = 12), autologous salvaged RBCs + minimal (<5 units) stored allogeneic RBCs (Auto+Allo min; n = 10), and autologous salvaged RBCs + moderate (≥5 units) stored allogeneic RBCs (Auto+Allo mod; n = 10). Ektacytometry was used to measure RBC elongation index (deformability) and critical shear stress (aggregation) before, during, and for 3 days after surgery. RESULTS:In the Auto group, RBC elongation index did not change significantly from the preoperative baseline. In the Auto+Allo min group, mean elongation index decreased from 32.31 ± 0.02 (baseline) to 30.47 ± 0.02 (nadir on postoperative day 1) (P = 0.003, representing a 6% change). In the Auto+Allo mod group, mean elongation index decreased from 32.7 ± 0.02 (baseline) to 28.14 ± 0.01 (nadir on postoperative day 1) (P = 0.0001, representing a 14% change). Deformability then dose-dependently recovered toward baseline over the first 3 postoperative days. Changes in aggregation were unrelated to transfusion (no difference among groups). For the 3 groups combined, mean critical shear stress decreased from 359 ± 174 mPa to 170 ± 141 mPa (P = 0.01, representing a 54% change), with the nadir at the end of surgery and returned to baseline by postoperative day 1. CONCLUSIONS:In cardiac surgery patients, transfusion with stored allogeneic RBCs, but not autologous salvaged RBCs, is associated with a decrease in RBC cell membrane deformability that is dose-dependent and may persist beyond 3 postoperative days. These findings suggest that autologous salvaged RBCs may be of higher quality than stored RBCs, since the latter are subject to the so-called storage lesions.

Efficacy of education followed by computerized provider order entry with clinician decision support to reduce red blood cell utilization

Two necessary components of a patient blood management program are education regarding evidence‐based transfusion guidelines and computerized provider order entry (CPOE) with clinician decision support (CDS). This study examines changes in red blood cell (RBC) utilization associated with each of these two interventions.

Compliance with Surgical Care Improvement Project for Body Temperature Management (SCIP Inf-10) Is Associated with Improved Clinical Outcomes.

Background:In an effort to measure and improve the quality of perioperative care, the Surgical Care Improvement Project (SCIP) was introduced in 2003. The SCIP guidelines are evidence-based process measures designed to reduce preventable morbidity, but it remains to be determined whether SCIP-measure compliance is associated with improved outcomes. Methods:The authors retrospectively analyzed the electronic medical record data from 45,304 inpatients at a single institution to assess whether compliance with SCIP Inf-10 (body temperature management) was associated with a reduced incidence of morbidity and mortality. The primary outcomes were hospital-acquired infection and ischemic cardiovascular events. Secondary outcomes were mortality and hospital length of stay. Results:Body temperature on admission to the postoperative care unit was higher in the SCIP-compliant group (36.6° ± 0.5°C; n = 44,064) compared with the SCIP-noncompliant group (35.5° ± 0.5°C; n = 1,240) (P < 0.0001). SCIP compliance was associated with improved outcomes in both nonadjusted and risk-adjusted analyses. SCIP compliance was associated with a reduced incidence of hospital-acquired infection (3,312 [7.5%] vs.160 [12.9%] events; risk-adjusted odds ratio [OR], 0.68; 95% CI, 0.54 to 0.85), ischemic cardiovascular events (602 [1.4%] vs. 38 [3.1%] events; risk-adjusted OR, 0.60; 95% CI, 0.41 to 0.92), and mortality (617 [1.4%] vs. 60 [4.8%] events; risk-adjusted OR, 0.41; 95% CI, 0.29 to 0.58). Median (interquartile range) hospital length of stay was also decreased: 4 (2 to 8) versus 5 (2 to 14) days; P < 0.0001. Conclusion:Compliance with SCIP Inf-10 body temperature management guidelines during surgery is associated with improved clinical outcomes and can be used as a quality measure.

Morbidity and Mortality after High-dose Transfusion.

Background:It is well recognized that increased transfusion volumes are associated with increased morbidity and mortality, but dose–response relations between high- and very-high-dose transfusion and clinical outcomes have not been described previously. In this study, the authors assessed (1) the dose–response relation over a wide range of transfusion volumes for morbidity and mortality and (2) other clinical predictors of adverse outcomes. Methods:The authors retrospectively analyzed electronic medical records for 272,592 medical and surgical patients (excluding those with hematologic malignancies), 3,523 of whom received transfusion (10 or greater erythrocyte units throughout the hospital stay), to create dose–response curves for transfusion volumes and in-hospital morbidity and mortality. Prehospital comorbidities were assessed in a risk-adjusted manner to identify the correlation with clinical outcomes. Results:For patients receiving high- or very-high-dose transfusion, infections and thrombotic events were four to five times more prevalent than renal, respiratory, and ischemic events. Mortality increased linearly over the entire dose range, with a 10% increase for each 10 units of erythrocytes transfused and 50% mortality after 50 erythrocyte units. Independent predictors of mortality were transfusion dose (odds ratio [OR], 1.037; 95% CI, 1.029 to 1.044), the Charlson comorbidity index (OR, 1.209; 95% CI, 1.141 to 1.276), and a history of congestive heart failure (OR, 1.482; 95% CI, 1.062 to 2.063). Conclusions:Patients receiving high- or very-high-dose transfusion are at especially high risk for hospital-acquired infections and thrombotic events. Mortality increased linearly over the entire dose range and exceeded 50% after 50 erythrocyte units.

Age of Transfused Blood Impacts Perioperative Outcomes Among Patients Who Undergo Major Gastrointestinal Surgery.

Objective: To evaluate the impact of transfused packed red blood cell (PRBC) age on perioperative morbidity among patients undergoing major gastrointestinal surgery. Background: Patients undergoing major surgery often receive PRBC transfusions. The effect of PRBC age (ie, storage duration before transfusion) on perioperative surgical outcomes remains poorly defined. Methods: In this study, 1365 patients were identified who underwent a hepato-pancreatic or colorectal resection and received ≥1 unit of PRBCs between 2009 and 2014 at the Johns Hopkins Hospital. Data regarding the storage duration of PRBCs, clinicopathologic characteristics, and perioperative outcomes were obtained and analyzed. Multivariable modified Poisson regression analyses were performed to assess the effect of PRBC age on perioperative morbidity. Results: A total of 5901 PRBC units were transfused for a median of 2 (interquartile range 2–4) units transfused per patient. In all, 936 (68.6%) patients received only units of blood that had been stored for less than 35 days (“fresh” blood), whereas 429 (31.4%) patients received at least 1 unit of PRBC that had been stored for ≥35 days (“older” blood). Overall postoperative morbidity was 32.8%. The incidence of postoperative complications (42.7% vs 28.3%) was higher among patients who received “older” vs “fresh” blood (P < 0.001). After adjusting for confounders on multivariable analysis, transfusion of “older” blood remained independently associated with an increased risk of perioperative morbidity (Relative Risk 1.20, P = 0.03). Conclusions: The use of “older” blood was an independent predictor of postoperative morbidity among patients undergoing hepato-pancreatic or colorectal procedures. Transfusion of “older” blood products may contribute to a higher risk of postoperative complications.

Development of a risk-adjusted blood utilization metric.

Blood utilization has become an important outcome measure for surgical patients because of the recognized risks and costs associated with transfusion. However, comparisons of blood utilization between providers or institutions are difficult, because there is no standard method for risk adjustment when assessing surgical blood requirements. We examined whether accepted diagnosis‐related group (DRG) case mix indexes can be used for this purpose.

Inotrope use in cardiac surgery: a cause of worse outcomes, or just a marker of patients who are at risk?

1. Insufficient information about the result of the matching process is provided, but enough to indicate what appears to be a significant flaw in methodology. First, their matching algorithm discarded a large number of both treatment and control patients (n = 6,005 patients were identified to be “included” in analysis; after propensity matching, only n = 2,340 [39%] remained). This implies a considerable lack of common support (overlap between the propensity score distributions of the two cohorts), which, even in the presence of a good match, increases risk of bias through unmeasured confounders and makes the estimate of the treatment effect unreliable.2 Second, the authors cite Donald Rubin (coinventor of propensity score matching), but use only one of the three metrics he recommends to judge the quality of a match: absolute standardized difference. Neither the variance ratios of the propensity scores between groups, nor the ratio of variance of the residuals of each covariate is reported.3,4 These are important, because the match is vulnerable to systematic differences in how the propensity scores were assigned. Finally, greedy matching depends on the order of patients, so it should be preceded by randomizing the order of patients in the dataset, which the authors do not report. 2. These design decisions in the propensity matching algorithm leave the study open to the possibility that these unmeasured confounders—and not the effect of inotropic therapy—are responsible for the observed outcome difference. Some variables were treated as overly simplistic dichotomous variables, which fail to capture important differences between patients, such that inotropic support may continue to act as nothing more than a marker for sicker patients with less well-functioning ventricles. Left ventricular ejection fraction was treated as a binary variable: less than or equal to 30% or greater than 30%. Therefore, their propensity matching would not differentiate between a patient with a baseline left ventricular ejection fraction of 35% and one with a baseline left ventricular ejection fraction of 65%. Duration of myocardial insult was captured only by cardiopulmonary bypass (CPB) time, again treated as a dichotomous variable (>120 min or ≤120 min). There are two problems with this decision: first, the need for inotropic support is more closely related to the duration of myocardial ischemia, i.e., the aortic cross-clamp time, than the time on bypass. Although CPB time is correlated with cross-clamp time, different surgeons may adopt different temporal approaches to weaning from bypass such that two surgeons with the same cross-clamp time will have very different CPB times. Indeed, the use of CPB time without cross-clamp time would prevent differentiation of a patient who had no aortic cross-clamp and no myocardial ischemia (e.g., a 1. Standards are needed for the evaluation of continuous noninvasive blood pressure monitoring systems. 2. These standards should probably define separate benchmarks for systolic, diastolic, and mean arterial pressure. Because systolic, diastolic, and mean arterial pressure are inherently different by nature, different acceptability threshold should be applied. 3. These standards should probably develop a methodology for assessing the trending ability of these systems. Because these systems will be used as continuous monitors in the clinical setting, their trending ability is as important as their instantaneous accuracy. 4. When such standards exist, clinician scientists should follow them carefully when conducting clinical studies testing these systems.

Compliance With Surgical Care Improvement Project for Body Temperature Management (SCIP Inf-10) Is Associated With Improved Clinical Outcome

Surgical Care Improvement Project Infection-10 (SCIP Inf-10) is an SCIP measure intended to reduce hospital-acquired infections and thereby improve quality of perioperative care. It states that patients who undergo surgical procedures lasting 60 minutes or longer should be actively warmed or have a body temperature of 36°C or higher within 30 minutes immediately before or 15 minutes after anesthesia end time. Unfortunately, there is little evidence that compliance with SCIP Inf-10 reduces perioperative morbidity. In this study, the authors sought to determine whether compliance with SCIP Inf-10 decreased the incidence of hospitalacquired infection, ischemic cardiovascular events, mortality rate, and length of stay. Electronic anesthesia records containing active patient warming measures and body temperatures of 45 304 inpatients, all of whom underwent noncardiac surgeries greater than 60 minutes in duration between January 2010 and June 2014, were obtained from 3 databases, merged, and retrospectively analyzed. Cardiac surgeries were excluded because of the unique thermal perturbations associated with these operations. Records were examined for evidence of hospital-acquired infections (postoperative wound, drug resistant, sepsis, and Clostridium difficile), myocardial infarctions, cerebral vascular accidents, and transient ischemic attacks. Records were then split into SCIP-compliant and SCIP-noncompliant groups. Statistical analysis included use of univariable, non–risk-adjusted, and multivariable models, for example, two-tailed Student t tests for continuous variables, χ test for dichotomous variables, and the Mann-Whitney U test for nonparametric analyses. Overall, the incidence of SCIP noncompliance decreased during the 4-year period (P ≤ 0.0001). Fewer patients received intraoperative blood transfusions in the SCIPcompliant group (9.2% vs 15.4%, P < 0.0001). For univariable analysis, incidence of drug-resistant, sepsis, andClostridium difficile infections was lower in the SCIP-compliant group than in the noncompliant group (7.5% vs 12.9%, P < 0.0001). Postoperative wound infections occurred with similar frequency in both groups and were not reduced with SCIP compliance. Ischemic cardiovascular events were less frequent in the SCIP-compliant group as well (1.4% vs 3.1%,P < 0.0001). The SCIP-compliant group also showed lower in-hospital mortality rate (1.4% vs 4.8%, P < 0.0001) and

A Novel Means of Assessing Institutional Adherence to Blood Transfusion Guidelines

Risk-adjusted institutional transfusion rates are not currently available on a national level. A surrogate means of benchmarking transfusion practices to use for internal quality improvement was studied. Blood utilization was prospectively studied among all colorectal surgery patients at the study institution (July 2010-November 2012), and these data were benchmarked with transfusion data from the National Surgical Quality Improvement Program (NSQIP) database by hospital type and size. Using NSQIP, the study institution’s colorectal surgery transfusion rate was 16.3% (150/920 cases), which was slightly higher than the 14.3% national mean transfusion rate (12 191/85 507 cases; P = .08). When broken down by hospital type and size, the study hospital had a similar rate of blood transfusion compared with academic hospitals (P = .35) but a significantly higher rate than community hospitals, regardless of patient volume (P = .03). Benchmarking blood utilization compared with similar-type hospitals using NSQIP may be a surrogate method to assess adherence to evidence-based transfusion guidelines and identify areas for structured quality improvement initiatives.