Platelet transfusions in adult ICU patients with thrombocytopenia: A sub-study of the PLOT-ICU inception cohort study

BACKGROUND

Platelet transfusions are frequently used in the intensive care unit (ICU), but current practices including used product types, volumes, doses and effects are unknown.

STUDY DESIGN AND METHODS

Sub-study of the inception cohort study 'Thrombocytopenia and Platelet Transfusions in the ICU (PLOT-ICU)', including acutely admitted, adult ICU patients with thrombocytopenia (platelet count <150 × 109/L). The primary outcome was the number of patients receiving platelet transfusion in ICU by product type. Secondary outcomes included platelet transfusion details, platelet increments, bleeding, other transfusions and mortality.

RESULTS

Amongst 504 patients with thrombocytopenia from 43 hospitals in 10 countries in Europe and the United States, 20.8% received 565 platelet transfusions; 61.0% received pooled products, 21.9% received apheresis products and 17.1% received both with a median of 2 (interquartile range 1-4) days from admission to first transfusion. The median volume per transfusion was 253 mL (180-308 mL) and pooled products accounted for 59.1% of transfusions, however, this varied across countries. Most centres (73.8%) used fixed dosing (medians ranging from 2.0 to 3.5 × 1011 platelets/transfusion) whilst some (mainly in France) used weight-based dosing (ranging from 0.5 to 0.7 × 1011 platelets per 10 kg body weight). The median platelet count increment for a single prophylactic platelet transfusion was 2 (-1 to 8) × 109/L. Outcomes of patients with thrombocytopenia who did and did not receive platelet transfusions varied.

CONCLUSIONS

Among acutely admitted, adult ICU patients with thrombocytopenia, 20.8% received platelet transfusions in ICU of whom most received pooled products, but considerable variation was observed in product type, volumes and doses across countries. Prophylactic platelet transfusions were associated with limited increases in platelet counts.

An evaluation of the clinical impacts of 7-day platelets

BACKGROUND

In August 2017, Canadian Blood Services extended the shelf-life of platelet concentrates from 5 to 7 days. The clinical impacts of this policy change remain unclear.

STUDY DESIGN AND METHODS

We used a before-after retrospective design of platelet-transfused adult inpatients in Hamilton, ON, Canada. Data were captured for 18 months before (Period 1: February 2016-July 2017) and 18 months after (Period 2: September 2017-February 2019) 7-day platelet implementation. Primary outcome was absolute platelet count increment (ACI) in univariate and multivariate analyses adjusted for confounders. Data were obtained from our institution's transfusion database, Ontario's Transfusion Transmitted Injuries Surveillance System, and the blood supplier.

RESULTS

Overall, 1360 patients with single dose platelet transfusions were included in Period 1 and 1211 patients in Period 2. Median age at admission was 66 years, and approximately 40% of patients underwent cardiac surgery. Using a non-inferiority margin of -10 × 10⁹ /L, platelets transfused during the 7-day storage period were non-inferior to those transfused in the 5-day storage period [mean count difference - 4.63 × 10⁹ /L (95% CI -7.40 to -1.87, p = 0.0001)]. However, platelet ACIs following transfusion consistently trended lower in the 7-day group for all patients and subgroups. No differences in secondary clinical outcomes were observed. Platelet expiry reduced from 8.1 to 6.3% (p < 0.0001).

CONCLUSION

Platelet transfusions following 7-day storage policy were non-inferior to transfusions in the 5-day policy period, although reduced ACIs were observed. There were no increases in adverse clinical outcomes.

Red blood cell volume, but not platelet or plasma volume is associated with mortality in neonatal ECMO

BACKGROUND

Blood product transfusions are necessary for critically ill neonates on extracorporeal membrane oxygenation (ECMO). Transfusions are administered in response to unstudied arbitrary thresholds and may be associated with adverse outcomes. The objective of this study was to identify relationships between blood product components and mortality in neonates receiving ECMO support for respiratory indications.

STUDY DESIGN AND METHODS

A retrospective review of neonates receiving ECMO for respiratory indications from 2002 to 2019 from a single quaternary-referral neonatal intensive care unit (NICU). Demographic and outcome data and transfusion volume (ml/kg/day) were harvested from the medical record, and baseline mortality risk was assessed using NEO-RESCUERS scores. The association between volume of red blood cells (RBC), platelet, plasma transfusion rates (ml/kg/day), and mortality on ECMO were assessed after adjustment for NEO-RESCUERS score. Cox proportional hazards (CPH) competing risk model was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for each variable and mortality outcome.

MEASUREMENTS AND MAIN RESULTS

Among 248 neonates undergoing ECMO for respiratory failure, overall survival was 93%. RBC, platelet, and plasma volume were highly associated with mortality during ECMO in an unadjusted model. After adjusting for NEO-RESCUERS score, RBC volume was associated with increased mortality risk (HR 1.013, 95% CI 1.004-1.022, p = .0043), but platelet and plasma volume were not associated with mortality.

CONCLUSIONS

RBC, but not platelet or plasma volume, is associated with mortality in neonates on ECMO. Our findings refute previous studies demonstrating an association between platelet volume and mortality for neonates on ECMO.

Platelet transfusions in a murine model of neonatal polymicrobial sepsis: Divergent effects on inflammation and mortality

BACKGROUND

Platelet transfusions (PTxs) are often given to septic preterm neonates at high platelet count thresholds in an attempt to reduce bleeding risk. However, the largest randomized controlled trial (RCT) of neonatal transfusion thresholds found higher mortality and/or major bleeding in infants transfused at higher thresholds. Using a murine model, we investigated the effects of adult PTx on neonatal sepsis-induced mortality, systemic inflammation, and platelet consumption.

STUDY DESIGN AND METHODS

Polymicrobial sepsis was induced via intraperitoneal injection of cecal slurry preparations (CS1, 2, 3) into P10 pups. Two hours after infection, pups were transfused with washed adult Green Flourescent Protein (GFP+) platelets or control. Weights, platelet counts, and GFP% were measured before 4 and 24 h post-infection. At 24 h, blood was collected for quantification of plasma cytokines.

RESULTS

The CS batches varied in 24 h mortality (11%, 73%, and 30% in CS1, 2, and 3, respectively), due to differences in bacterial composition. PTx had differential effects on sepsis-induced mortality and systemic inflammatory cytokines, increasing both in mice infected with CS1 (low mortality) and decreasing both in mice infected with CS2 and 3. In a mathematical model of platelet kinetics, the consumption of transfused adult platelets was higher than that of endogenous neonatal platelets, regardless of CS batch.

DISCUSSION

Our findings support the hypothesis that transfused adult platelets are consumed faster than endogenous neonatal platelets in sepsis and demonstrate that PTx can enhance or attenuate neonatal inflammation and mortality in a model of murine polymicrobial sepsis, depending on the composition of the inoculum and/or the severity of sepsis.

Thrombocytopenia in intensive care unit patients: A scoping review

BACKGROUND

Thrombocytopenia is frequent in intensive care unit (ICU) patients and may be associated with adverse outcomes. We aimed to assess the incidence, risk factors, and outcomes associated with thrombocytopenia in adult ICU patients.

METHODS

We conducted a scoping review in accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses extension for Scoping Reviews (PRISMA-ScR) and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. We included study reports on adult ICU patients with thrombocytopenia and assessed patient-important outcomes, including mortality and health-related quality-of-life.

RESULTS

We included a total of 70 studies comprising a total of 215 098 patients; 57 were cohort studies. The incidence of thrombocytopenia varied from 8 to 56 per 100 admissions (very low quality of evidence). We identified several risk factors including age, sepsis, and higher disease severity (low quality of evidence). Thrombocytopenia was associated with bleeding, use of life support, length of stay in the ICU, and increased mortality (low/very low quality of evidence). Data on platelet transfusion before invasive procedures and transfusion thresholds were limited. No studies assessed the benefits and harms of thromboprophylaxis in ICU patients with thrombocytopenia.

CONCLUSIONS

Thrombocytopenia is common and associated with increased morbidity and mortality in adult ICU patients. Several risk factors for thrombocytopenia exists, but the evidence-base on management strategies, including transfusion thresholds and thromboprophylaxis in ICU patients is very limited.

Clinical Implications of Thrombocytopenia at Cardiogenic Shock Presentation: Data from a Multicenter Registry

PURPOSE

Thrombocytopenia (platelet count <150×10³/μL) is associated with poor outcomes in various critical illness settings. However, the prognostic value of platelet count in patients with cardiogenic shock (CS) remains unclear.

MATERIALS AND METHODS

We enrolled 1202 patients between January 2014 and December 2018 from a multicenter retrospective-prospective cohort registry of CS. Clinical characteristics and treatment outcomes were compared between the patients with and without thrombocytopenia.

RESULTS

At presentation with CS, 244 (20.3%) patients had thrombocytopenia. The patients with thrombocytopenia had lower blood pressure, hemoglobin level, and worse liver and renal functions compared to the patients without. During hospitalization, the patients with thrombocytopenia had more frequent gastrointestinal bleeding (10.5% vs. 3.8%, p=0.009), sepsis (8.3% vs. 2.6%, p=0.013), requirement of renal replacement therapy (36.5% vs. 18.9%, p<0.001), requirement of mechanical ventilation (65.2% vs. 54.4%, p=0.003), longer intensive care unit stay (8 days vs. 4 days, p<0.001), and thirty-day mortality (40.2% vs. 28.5%, p<0.001) compared to those without. In addition, the platelet count was an independent predictor of 30-day mortality (per 10³/μL decrease; adjusted hazard ratio: 1.002, 95% confidence interval: 1.000-1.003, p=0.021).

CONCLUSION

Thrombocytopenia at CS presentation was associated with worse clinical findings, higher frequencies of complications, and longer stay at the intensive care unit. Also, thrombocytopenia was independently associated with increased 30-day mortality. (Clinical trial registration No. NCT02985008).

The epidemiology of platelet transfusions: an analysis of platelet use at 12 US hospitals

BACKGROUND

Using the Recipient and Donor Epidemiology Study-III (REDS-III) recipient and donor databases, we performed a retrospective analysis of platelet use in 12 US hospitals that were participants in REDS-III.

STUDY DESIGN AND METHODS

Data were electronically extracted from participating transfusion service and blood center computer systems and from medical records of the 12 REDS-III hospitals. All platelet transfusions from 2013 to 2016 given to patients aged 18 years and older were included in the analysis.

RESULTS

There were 28,843 inpatients and 2987 outpatients who were transfused with 163,719 platelet products (103,371 apheresis, 60,348 whole blood derived); 93.5% of platelets were leukoreduced and 72.5% were irradiated. Forty-six percent were transfused to patients with an International Classification of Diseases, 9th/10th Revision (ICD-9/10) diagnosis of leukemia, myelodysplastic syndrome (MDS), or lymphoma. The general ward and the intensive care unit (ICU) were the most common issue locations. Only 54% of platelet transfusions were ABO identical; and 60.6% of platelet transfusions given to Rh-negative patients were Rh positive. The most common pretransfusion platelet count range for inpatients was 20,000 to 50,000/μL, for outpatients it was 10,000 to 20,000/μL. Among ICU patients, 35% of platelet transfusion episodes had a platelet count of greater than 50,000/μL; this was only 8% for general ward and 2% for outpatients. The median posttransfusion increment, not corrected for platelet dose and/or patient size, ranged from 12,000 to 20,000/μL for inpatients, and from 17,000 to 27,000/μL for outpatients.

CONCLUSIONS

These data from one of the largest reviews of platelet transfusion practice to date provide guidance for where to focus future clinical research studies and platelet blood management programs.