TRISS: Lower versus Higher Hgb Threshold for Transfusion in Septic Shock
Holst L et al. "Lower versus Higher Hemoglobin Threshold for Transfusion in Septic Shock". The New England Journal of Medicine. 2014; 371:1381-1391 .
Link to Article: https://www.nejm.org/doi/full/10.1056/NEJMoa1406617
Clinical Question
In patients with septic shock, does blood transfusion at a lower or higher hemoglobin threshold improve mortality?
Type of Trial: RCT
Setting: 32 general ICUs in Scandinavia from Dec 2011 - Dec 2013
PICO
Population:
All patients with septic shock and Hgb<9
Excluded: patients with ACS, previous adverse reaction to transfusion, life threatening bleeding, acute burn, withdrew from active therapy
In comparing intervention/control group no significant difference in baseline characteristics; most common source of sepsis lungs (53.2% vs 52.2%)
Intervention:
Transfusion threshold of <7 g/dl
Control:
Transfusion threshold of <9 g/dl
In both intervention/control:
Pts given single unit crossmatched, prestorage leukoreduced red cells when met threshold
Intervention period was entire ICU stage (max of 90d after randomization)
If life threatening bleeding, ischemia or ECMO required then attending doctor could transfuse Hgb at their own threshold
Outcome:
Primary outcome: death by 90 days
No significant difference (43.0% intervention vs 45.0% control, P=0.44)
Secondary outcomes:
Median number of blood transfusions - lower in lower threshold (43.0% intervention vs 45.0% control, P=0.44)
Number of patients that did not undergo transfusion - significantly more in lower threshold (43.0% intervention vs 45.0% control, P=0.44)
No significant difference in:
use of life support at days 5/ 14/ 28 (64.4%/36.8%/16.1% intervention 62.2%/36.8%/19.9% control, P=0.47/0.95/0.14)
alive wo vasopressor or inotropic support (73.0% intervention vs 75.0% control, P=0.93)
alive w/o mechanical ventilation (65.0% intervention vs 67.0% control, P=0.49)
alive w/o renal replacement therapy (85.0% intervention vs 83.0% control, P=0.54)
percentage of days alive and out of hospital (30d intervention vs 31d control, P=0.89)
Severe complications: no significant difference
Ischemic event: 7.2% intervention vs 8.0% control, P=0.64
Severe adverse rxn: 0% intervention vs 0.2% control, P=1.00
Sub-group analysis: no sig difference in primary outcome based on presence/abscence of chronic CV disease, age> or < 70, SAPS II of > or <53
Conclusions
In patients with septic shock, mortality and rates of ischemic events were similar in those assigned to a blood transfusion at a higher vs. lower threshold .
Strengths
Randomized
Blinding of investigators assessing primary outcome
Multi-center
Weaknesses
Non-blinding of staff (although unrealistic to achieve)
Protocol violations: patients were more likely to be given transfusion as either a suspension or violation if target <7 and more likely to have transfusion if threshold <9
Take Note
Patients with ACS were excluded; further research is needed in this group
Having a lower transfusion threshold does NOT result in difference in mortality or ischemic events; but it does remove risk of infectious, immune complications and conserves limited resource
Sources:
https://www.thebottomline.org.uk
