Impact of restrictive platelet transfusion strategies on transfusion rates: A cohort study in very preterm infants.

BACKGROUND: Evidence supports a restrictive platelet transfusion threshold in preterm neonates. We aimed to describe the effect of implementing this threshold on transfusion rates. STUDY DESIGN AND METHODS: This retrospective observational cohort study included all very preterm infants (born <32 weeks' gestation) admitted to a neonatal intensive care unit between 2004 and 2022, divided into three epochs. Platelet transfusion thresholds changed from 30 × 109/L for stable neonates and 50 × 109/L for unstable neonates (January 2004 to December 2009) to 20 × 109/L for stable neonates and 50 × 109/L for unstable neonates (January 2010 to June 2019) to 25 × 109/L for non-bleeding neonates and 50 × 109/L for neonates with major bleeding (July 2019 to July 2022). The primary outcome was the percentage of transfused neonates in each epoch. Secondary outcomes included the median number of transfusions per neonate, the percentage of transfusions given above 25 or 50 × 109/L, and major bleeding and mortality rates. RESULTS: The percentage of neonates transfused was 12.2% (115/939), 5.8% (96/1660), and 4.8% (25/525) in Epoch I, II, and III, respectively (p < .001), a relative reduction of 61%. The median number of transfusions per transfused neonate was 2.0 (interquartile range [IQR]: 1.0-3.0) in Epoch I, and 1.0 (IQR: 1.0-2.0) in subsequent Epochs (p = .04). The percentage of infants receiving at least one transfusion above 50 × 109/L in Epoch I, II, and III was 51.3% (59/115), 17.7% (17/96), and 20.0% (5/25; p < .001). Mortality and bleeding rates did not significantly differ between epochs. DISCUSSION: Implementation of restrictive platelet guidelines led to reduction of the rate and number of platelet transfusions.

Effect of storage time of platelet products on clinical outcomes after transfusion: a systematic review and meta-analyses.

BACKGROUND: Prolonged storage improves availability of platelet products but could also influence safety and efficacy. This systematic review and meta-analyses summarize and quantify the evidence of the effect of storage time of transfused platelets on clinical outcomes. METHODS: A systematic search in seven databases was performed up to February 2016. All studies reporting storage time of platelet products and clinical outcomes were included. To quantify heterogeneity, I² was calculated, and to assess publication bias, funnel plots were constructed. RESULTS: Twenty-three studies reported safety outcomes and fifteen efficacy outcomes. The relative risk of a transfusion reaction after old platelets compared to fresh platelets was 1·53 (95% confidence interval (CI): 1·04-2·25) (12 studies). This was 2·05 (CI:1·47-2·85) before and 1·05 (CI: 0·60-1·84) after implementation of universal leucoreduction. The relative risk of bleeding was 1·13 (CI: 0·97-1·32) for old platelets compared to fresh (five studies). The transfusion interval was 0·25 days (CI: 0·13; 0·38) shorter after transfusion of old platelets (four studies). Three studies reported use of platelet products: two for haematological patients and one for trauma patients. Selecting only studies in haematological patients, the difference was 4·51 units (CI: 1·92; 7·11). CONCLUSION: Old platelets increase the risk of transfusion reactions in the setting of non-leucoreduction, shorten platelet transfusion intervals, thereby increase the numbers of platelet transfusions in haematological patients, and may increase the risk of bleeding.

Effect of platelet storage time on platelet measurements: a systematic review and meta-analyses.

BACKGROUND: The storage time of platelet products negatively affects bacterial safety and platelet function. However, low maximum storage time increases outdating of valuable products. Thus, to quantify the effect of platelet storage time on platelet measurements after platelet transfusion, a systematic review and meta-analyses were performed. METHODS: Reports and meeting abstracts of randomized trials and observational studies, performed in humans, reporting platelet measurements after transfusion of platelet products of different storage times, were selected until February 2016. Meta-analyses were performed for four different storage time contrasts, each answering a different question. Random-effects models were used to account for substantial heterogeneity and the weighted mean differences calculated. RESULTS: Our search strategy yielded 4234 studies of which 46 papers satisfied the inclusion criteria. As judged by the 1-h corrected count increment, transfusions of fresher platelets compared to stored platelets showed better increment. The weighed mean difference varied from 2·11 (95%CI: 1·51-2·71) to 2·68 (95%CI: 1·92-3·45). For the 24-h corrected count increment, the weighted mean difference varied from 1·36 (95%CI: 0·12-2·60) to 1·68 (95%CI: 1·07-2·28) depending on the contrast. Recovery and survival of old platelets as percentage of fresh platelets were 81% and 73% for the original definition contrast. For the extended storage contrast, recovery and survival were 75% and 68%. CONCLUSIONS: Fresh platelets were superior to old platelets for all platelet measurements and for all storage time contrasts meta-analysed.

Mitochondrial oxygen tension in critically ill patients receiving red blood cell transfusions: a multicenter observational cohort study.

PURPOSE: Currently, there is no marker of efficacy of red blood cell (RBC) transfusion. This study describes the impact of RBC transfusion on mitochondrial oxygen tension (mitoPO2) and mitochondrial oxygen consumption (mitoVO2) in critically ill patients with anemia. METHODS: Critically ill patients with a hemoglobin concentration < 10 g/dL, for whom a single RBC unit had been ordered, were included. MitoPO2 was measured with the COMET device immediately before RBC transfusion, 0.5 h, 1 h, 3 h, and 24 h after RBC transfusion. MitoVO2 was calculated from dynamic mitoPO2 measurements during cessation of local oxygen supply. RESULTS: Sixty-three patients participated, median age 64.0 (interquartile range (IQR) 52.3-72.8) years, median hemoglobin concentration before transfusion 7.4 (IQR 7.1-7.7) g/dL. Median mitoPO2 values were 55.0 (IQR 49.6-63.0) mmHg before RBC transfusion, 51.0 (IQR 41.5-61.2) directly after and 67.3 (IQR 41.6-83.7) at 24 h after RBC transfusion. Median mitoVO2 values were 3.3 (IQR 2.1-5.9) mmHg/s before RBC transfusion, 3.7 (IQR 2.0-5.1) mmHg/s directly after, and 3.1 (IQR 2.5-4.8) mmHg/s 24 h after RBC transfusion. In the higher Hb concentration group (> 7 g/dL), we saw a dissociation of the effect of RBC transfusion on mitoPO2 versus on mitoVO2 values. MitoPO2 and mitoVO2 values were not associated with commonly used parameters of tissue perfusion and oxygenation. CONCLUSION: RBC transfusion did not alter mitoPO2 and mitoVO2 in critically ill patients with anemia. MitoPO2 and mitoVO2 values were not notably associated with Hb concentrations, parameters of severity of illness and markers of tissue perfusion or oxygenation. Given the high baseline value, it cannot be excluded nor confirmed whether RBC can improve low mitoPO2. Trial registration number NCT03092297 (registered 27 March 2017).

Severe postpartum hemorrhage and the risk of adverse maternal outcome: A comparative analysis of two population-based studies in France and the Netherlands.

Objectives: Among women with severe PPH (sPPH) in France and the Netherlands, we compared incidence of adverse maternal outcome (major obstetric hemorrhage (≥2.5L blood loss) and/or hysterectomy and/or mortality) by mode of delivery. Second, we compared use and timing of resuscitation and transfusion management, second-line uterotonics and uterine-sparing interventions (intra-uterine tamponade, compression sutures, vascular ligation, arterial embolization) by mode of delivery. Methods:  Secondary analysis of two population-based studies of women with sPPH in France and the Netherlands. Women were selected by a harmonized definition for sPPH: (total blood loss ≥ 1500 ml) AND (blood transfusion of ≥ 4 units packed red blood cells and/or multicomponent blood transfusion). Findings: Incidence of adverse maternal outcome after vaginal birth was 793/1002, 9.1 % in the Netherlands versus 88/214, 41.1 % in France and 259/342, 76.2% versus 160/270, 59.3% after cesarean. Hemostatic agents such as fibrinogen were administered less frequently (p < 0.001) in the Netherlands (vaginal birth: 83/1002, 8.3% versus 105/2014, 49.5% in France; cesarean: 47/342, 13.7% and 152/270, 55.6%). Second-line uterotonics were started significantly later after PPH-onset in the Netherlands than France (vaginal birth: 46 versus 25 min; cesarean: 45 versus 18 min). Uterine-sparing interventions were less frequently (p < 0.001) applied in the Netherlands after vaginal birth (394/1002,39.3 %, 134/214, 62.6%) and cesarean (133/342, 38.9 % and 155/270, 57.4%), all initiated later after onset of refractory PPH in the Netherlands. Interpretation: Incidence of adverse maternal outcome was higher among women with sPPH in the Netherlands than France regardless mode of birth. Possible explanatory mechanisms are earlier and more frequent use of second-line uterotonics and uterine-sparing interventions in France compared to the Netherlands.