Randomized Controlled Study on Safety and Feasibility of Transfusion Trigger Score of Emergency Operations

A physiology-based trigger score to guide perioperative transfusion of allogeneic red blood cells: A multicentre randomised controlled trial

BACKGROUND

Restrictive blood transfusion is recommended by major guidelines for perioperative management, but requires objective assessment at 7-10 g/dl haemoglobin (Hb). A scoring system that considers the physiological needs of the heart may simply the practice and reduce transfusion.

METHODS

Patients (14-65 years of age) undergoing non-cardiac surgery were randomised at a 1:1 ratio to a control group versus a Perioperative Transfusion Trigger Score (POTTS) group. POTTS (maximum of 10) was calculated as 6 plus the following: adrenaline infusion rate (0 for no infusion, 1 for ≤0.05 μg·kg^-1 ·min^-1 , and 2 for higher rate), FiO₂ to keep SpO₂ at ≥95% (0 for ≤35%, 1 for 36%-50%, and 2 for higher), core temperature (0 for <38°C, 1 for 38-40°C, and 2 for higher), and angina history (0 for no, 1 for exertional, and 2 for resting). Transfusion is indicated when actual Hb is lower than the calculated POTTS in individual patients. Transfusion in the control group was based on the 2012 American Association for Blood Banks (AABB) guideline. The primary outcome was the proportion of the patients requiring transfusion of allogeneic red blood cells (RBCs) during the perioperative period (until discharge from hospital), as assessed in the intention-to-treat (ITT) population (all randomised subjects).

RESULT

A total of 864 patients (mean age 44.4 years, 244 men and 620 women) were enrolled from December 2017 to January 2021 (433 in the control and 431 in the POTTS group). Baseline Hb was 9.2 ± 1.8 and 9.2 ± 1.7 g/dl in the control and POTTS groups, respectively. In the ITT analysis, the proportion of the patients receiving allogeneic RBCs was 43.9% (190/433) in the control group versus 36.9% (159/431) in the POTTS group (p = 0.036). Lower rate of allogeneic RBCs transfusion in the POTTS group was also evident in the per-protocol analysis (42.8% vs. 35.5%, p = 0.030). Transfusion volume was 4.0 (2.0, 6.0) and 3.5 (2.0, 5.5) units (200 ml/unit) in the control and POTTS groups, respectively (p = 0.25). The rate of severe postoperative complications (Clavien-Dindo grade IIIa and higher) was 3.9% in the control group versus 1.2% in the POTTS group (p = 0.010).

CONCLUSION

Transfusion of allogeneic RBCs based on the POTTS was safe and reduced the transfusion requirement in patients undergoing non-cardiac surgery.

Postoperative Nadir Hemoglobin and Adverse Outcomes in Patients Undergoing On-Pump Cardiac Operation

BACKGROUND

Patients undergoing cardiac operation are susceptible to anemia. Low hemoglobin concentration is a risk factor for composite adverse events and death after cardiac operation. Here we investigated the association of postoperative nadir hemoglobin with adverse outcomes in patients undergoing on-pump cardiac operation.

METHODS

Adult patients in 2 medical centers were retrospectively analyzed. The primary outcome was postoperative composite adverse events. The secondary outcome was all-cause death in the hospital.

RESULTS

Of the 8206 patients analyzed, 1628 (19.8%) experienced composite adverse events after operation and 109 (1.3%) died. Patients receiving on-pump cardiac operation with nadir hemoglobin of 9.0 to 9.9 g/L showed a low incidence of composite adverse events (175 of 1423 [12.3%]) and death (5 of 1423 [0.4%]). Compared with nadir hemoglobin at 9.0 to 9.9 g/dL, the relative risk (RR) of composite adverse events increased stepwise as nadir hemoglobin fell below 9.0 g/dL: adjusted RR was 1.44 (95% confidence interval [CI], 1.14-1.83) for 8.5 to 8.9 g/dL, 1.56 (95% CI, 1.23-1.99) for 8.0 to 8.4 g/dL, 1.66 (95% CI, 1.31-2.11) for 7.5 to 7.9 g/dL, 2.22 (95% CI, 1.75-2.83) for 7.0 to 7.4 g/dL, and 4.00 (95% CI, 3.18-5.04) for less than 7 .0 g/dL. Furthermore, the risk of death was significantly higher when nadir hemoglobin was below 7.0 g/dL than when it was 9.0 to 9.9 g/dL (RR, 5.36; 95% CI, 2.20-16.12).

CONCLUSIONS

Compared with the risks when nadir hemoglobin is 9.0 to 9.9 g/dL, the risk of composite adverse events increases when postoperative nadir hemoglobin is below 9.0 g/dL, whereas risk of death increases when nadir hemoglobin is below 7.0 g/dL.

Evaluation of a novel Cardiac Peri-Operative Transfusion Trigger Scoring system in patients with coronary artery disease

BACKGROUND

A simple and accurate scoring system to guide perioperative blood transfusion in patients with coronary artery disease (CAD) undergoing cardiac surgery is lacking. The trigger point for blood transfusions for these patients may be different from existing transfusion guidelines. This study aimed to evaluate the safety and efficacy of a new scoring strategy for use in guiding transfusion decisions in patients with CAD.

METHODS

A multicenter randomized controlled trial was conducted at three third-level grade-A hospitals from January 2015 to May 2018. Data of 254 patients in a Cardiac Peri-Operative Transfusion Trigger Score (cPOTTS) group and 246 patients in a group receiving conventional evaluation of the need for transfusion (conventional group) were analysed. The requirements for transfusion and the per capita consumption of red blood cells (RBCs) were compared between groups.

RESULTS

Baseline characteristics of the two groups were comparable. Logistic regression analyses revealed no significant differences between the two groups in primary outcomes (1-year mortality and perioperative ischemic cardiac events), secondary outcomes (shock, infections, and renal impairment), ICU admission, and ICU stay duration. However, patients in the cPOTTS group had significantly shorter hospital stays, lower hospital costs, lower utilization rate and lower per capita consumption of transfused RBCs than controls. Stratified analyses revealed no significant differences between groups in associations between baseline characteristics and perioperative ischemic cardiac events, except for hemofiltration or dialysis and NYHA class in I.

CONCLUSIONS

This novel scoring system offered a practical and straightforward guideline of perioperative blood transfusion in patients with CAD. Trial registration chiCTR1800016561(2017/7/19).

Restrictive Versus Liberal Strategy for Red Blood-Cell Transfusion: A Systematic Review and Meta-Analysis in Orthopaedic Patients

BACKGROUND

Current guidelines recommend restrictive criteria for red blood-cell transfusion in most clinical settings. However, patients undergoing orthopaedic surgery may require distinct transfusion criteria since benefits and potential harm often vary considerably based on patient characteristics and surgical procedures. We aimed to assess the efficacy and safety of restrictive transfusion in patients undergoing orthopaedic surgery, especially in important subgroups.

METHODS

Electronic databases were searched to identify randomized controlled trials investigating restrictive (mostly a hemoglobin level of 8.0 g/dL or symptomatic anemia) versus liberal (mostly a hemoglobin level of 10.0 g/dL) transfusion in patients undergoing orthopaedic surgery. For the primary outcome of cardiovascular events, we performed random-effects meta-analyses to synthesize the evidence and to assess the effects in different subgroups according to patient characteristics (with versus without preexisting cardiovascular disease) and surgical procedures (hip fracture surgery versus elective arthroplasty).

RESULTS

Ten trials involving 3,968 participants who underwent hip or knee surgery were included. Mean participant age ranged from 68.7 to 86.9 years. Compared with liberal transfusion, restrictive transfusion increased the risk of cardiovascular events (8 trials; 3,618 participants; relative risk [RR], 1.51; 95% confidence interval [CI], 1.16 to 1.98; p = 0.003; with no heterogeneity across all trials), irrespective of preexisting cardiovascular disease (pinteraction = 0.63). In a subgroup analysis, the increase was observed in patients undergoing hip fracture surgery (RR, 1.51; 95% CI, 1.08 to 2.10; p = 0.02), but did not reach significance in those undergoing elective arthroplasty (RR, 1.53; 95% CI, 0.96 to 2.44; p = 0.07). To minimize the bias caused by variations in transfusion threshold, we conducted an analysis that only included trials using 8.0 g/dL hemoglobin or symptomatic anemia as the threshold for restrictive transfusion and obtained identical results (6 trials; 2,872 participants; RR, 1.51; 95% CI, 1.09 to 2.08; p = 0.01; I = 0%). The 2 arms did not differ with respect to the rates of all infections, 30-day mortality, thromboembolic events, wound infection, pulmonary infection (mainly pneumonia), and cerebrovascular accidents (mainly stroke).

CONCLUSIONS

In patients undergoing orthopaedic surgery, when compared with liberal transfusion, restrictive transfusion increases the risk of cardiovascular events irrespective of preexisting cardiovascular disease. Importantly, the increased risk was observed in patients undergoing hip fracture surgery but did not reach significance in those undergoing elective arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Effect of restrictive versus liberal transfusion strategies on outcomes in patients with cardiovascular disease in a non-cardiac surgery setting: systematic review and meta-analysis

OBJECTIVE

To compare patient outcomes of restrictive versus liberal blood transfusion strategies in patients with cardiovascular disease not undergoing cardiac surgery.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Randomised controlled trials involving a threshold for red blood cell transfusion in hospital. We searched (to 2 November 2015) CENTRAL, Medline, Embase, CINAHL, PubMed, LILACS, NHSBT Transfusion Evidence Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, ISRCTN Register, and EU Clinical Trials Register. Authors were contacted for data whenever possible.

TRIAL SELECTION

Published and unpublished randomised controlled trials comparing a restrictive with liberal transfusion threshold and that included patients with cardiovascular disease.

DATA EXTRACTION AND SYNTHESIS

Data extraction was completed in duplicate. Risk of bias was assessed using Cochrane methods. Relative risk ratios with 95% confidence intervals were presented in all meta-analyses. Mantel-Haenszel random effects models were used to pool risk ratios.

MAIN OUTCOME MEASURES

30 day mortality, and cardiovascular events.

RESULTS

41 trials were identified; of these, seven included data on patients with cardiovascular disease. Data from a further four trials enrolling patients with cardiovascular disease were obtained from the authors. In total, 11 trials enrolling patients with cardiovascular disease (n=3033) were included for meta-analysis (restrictive transfusion, n=1514 patients; liberal transfusion, n=1519). The pooled risk ratio for the association between transfusion thresholds and 30 day mortality was 1.15 (95% confidence interval 0.88 to 1.50, P=0.50), with little heterogeneity (I(2)=14%). The risk of acute coronary syndrome in patients managed with restrictive compared with liberal transfusion was increased (nine trials; risk ratio 1.78, 95% confidence interval 1.18 to 2.70, P=0.01, I(2)=0%).

CONCLUSIONS

The results show that it may not be safe to use a restrictive transfusion threshold of less than 80 g/L in patients with ongoing acute coronary syndrome or chronic cardiovascular disease. Effects on mortality and other outcomes are uncertain. These data support the use of a more liberal transfusion threshold (>80 g/L) for patients with both acute and chronic cardiovascular disease until adequately powered high quality randomised trials have been undertaken in patients with cardiovascular disease.

REGISTRATION

PROSPERO CRD42014014251.