Platelet mass index (PMI) as a prognostic indicator in pediatric sepsis has not been previously reported. In this retrospective observational study, we evaluated PMI\'s performance as a prognostic indicator in children aged younger than 18 years with sepsis and septic shock in relationship with survival. Over 5 years, we collected data from 122 children admitted to our pediatric intensive care unit (PICU). PMI accuracy was assessed with sensitivity and specificity and its discrimination was assessed using the area under the receiver operating characteristic curve (AUC). Median PMI values on days 1 and 3 of PICU admission were lower among nonsurvivors. On day 1 of PICU admission, a cutoff PMI value of 1,450 fL/nL resulted in a sensitivity of 72% and a specificity of 69%, and the AUC was 0.70 (95% confidence interval [CI]: 0.55-0.86). Similarly, on day 3, a cutoff of 900 fL/nL resulted in a sensitivity of 71% and a specificity of 70%, and the AUC was 0.76 (95% CI: 0.59-0.92). Our exploratory study suggests that low PMI in children with septic shock is associated with increased mortality. Considering the PMI\'s fair performance, further studies should be performed to assess its clinical value.

OBJECTIVE: To evaluate the association between hematological parameters on the first day of life and bronchopulmonary dysplasia (BPD) in preterm infants.
METHODS: This retrospective study involved all premature infants admitted to our neonatal intensive care unit from January 2017 to June 2022. BPD was diagnosed based on hypoxia exposure for ≥28 days. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), platelet count (PLT), mean platelet volume (MPV), and platelet mass index (PMI) were compared between infants with and without BPD. Multivariate analysis was conducted to evaluate the association between hematological parameters and BPD.
RESULTS: This study involved 124 premature infants (48 with BPD, 76 without BPD). The BPD group had a lower gestational age and lower weight. The NLR, MPV, and PLR were considerably higher and the PLT and MPI were lower in the BPD than non-BPD group. After adjusting for covariates, logistic regression analysis suggested that the NLR, PLT, and PMI were independent risk factors for BPD. Moreover, the receiver operating characteristic curve indicated that the NLR, PLT, and PMI were reliable predictors of BPD.
CONCLUSIONS: Our findings suggest that a higher NLR and a lower PLT and PMI on the first day may increase the risk of BPD.

To evaluate the usability of platelet mass index (PMI) thresholds to assess the repeated platelet transfusion requirements in neonates who have received transfusion within the previous six days. This is a retrospective cross-sectional study conducted with neonates who received prophylactic platelet transfusion. The PMI was calculated as platelet count (× 1000/mm3) × mean platelet volume (MPV) (fL). Platelet transfusions were divided into two groups as first (Group 1) and repeated transfusions (Group 2). The increment and percentage of increment in platelet counts, MPV and PMI after transfusion were compared between the two groups. The amounts of changes were calculated as: (Post-transfusion) - (Pre-transfusion values). The percentages of changes were calculated as: ([Post-transfusion - Pre-transfusion values]/Pre-tansfusion values) × 100. Eighty three platelet transfusions were analyzed in 28 neonates. The median gestational age and birth weight were 34.5 (26-37) weeks, and 2225 (752.5-2937.5) grams, respectively. There were 20 (24.1%) transfusions in Group 1, and 63 (75.9%) transfusions in Group 2. There were no differences in the amounts of changes in platelet counts, MPV and PMI between the groups (p > 0.05). When the percentages of changes were analyzed, it was found that the platelet counts and PMI in Group 1 increased to a greater extent compared to Group 2 (p = 0.026, p = 0.039, respectively), but no significant difference was found in MPV between the groups (p = 0.081). The lower percentage of change in PMI in Group 2 was associated with the lower percentage of change in platelet counts. Being transfused with adult platelets did not affect platelet volume of the neonates. Therefore, PMI thresholds can be used in neonates with a history of platelet transfusion.

BACKGROUND: Atrial fibrillation (AF) is the most common complication after cardiac surgery. The pathogenesis of postoperative atrial fibrillation (POAF) is multifactorial and one of the known factors is inflammation. Platelet mass index (PMI) is an indicator of platelet activation and a better inflammatory marker than mean platelet volume (MPV). In this retrospective study, we investigated the relationship between POAF and PMI.
METHODS: The study included 848 consecutive patients (655 male and 193 female) who had elective isolated coronary artery by-pass grafting (CABG) or combined CABG and valvular surgery. Platelet count and MPV were measured from preoperative blood samples to calculate PMI. Post-operative atrial fibrillation was defined as irregular and fibrillatory P waves occurring 48-96 h after cardiac surgery and lasting at least 30 s. The PMI values in patients who developed POAF were compared with those in patients who did not develop POAF.
RESULTS: Patients who developed POAF had higher PMI values (2549.3 ± 1077.1) when compared with patients in sinus rhythm (2248.1 ± 683.4; p < 0.01). In multivariate regression analysis, age (OR: 1.05; 95% CI: 1.02-1.09; p = 0.01), left atrial diameter (OR: 1.05; 95% CI: 1.03-1.09; p = 0.02), hs-CRP (OR: 1.09; 95%CI: 1.05-1.13; p < 0.01), EuroSCORE II (OR: 1.27; 95% CI: 1.14-1.41; p < 0.01), and PMI (OR: 1.01; 95% CI: 1.001-1.02; p < 0.01) were independent predictors of POAF. In ROC analysis, PMI ≥ 2286 predicted POAF development with a sensitivity of 69% and a specificity of 58% (AUC: 0.66; p < 0.01) CONCLUSION: A significant relationship was found between preoperatively calculated PMI and POAF. We showed that PMI may be used to predict patients who are at high risk of developing POAF.
UNASSIGNED: HINTERGRUND: Vorhofflimmern („atrial fibrillation“, AF) stellt die häufigste Komplikation nach Herzoperationen dar. Die Pathogenese des postoperativen AF (POAF) ist multifaktoriell, und einer der bekannten Faktoren ist die Entzündung. Der Plättchenmassenindex (PMI) dient als Indikator der Plättchenaktivierung und stellt einen besseren Entzündungsmarker als das mittlere Plättchenvolumen (MPV) dar. In der vorliegenden retrospektiven Studie wurde der Zusammenhang zwischen POAF und PMI untersucht.
METHODS: In die Studie wurden 848 konsekutive Patienten einbezogen (655 Männer und 193 Frauen), bei denen eine elektive isolierte Koronararterienbypassoperation (CABG) oder eine Kombination aus CABG und Klappenchirurgie durchgeführt worden war. Plättchenzahl und MPV wurden anhand von präoperativen Blutproben ermittelt, um dann den PMI zu berechnen. Ein POAF war definiert als irreguläre und fibrillatorische P‑Wellen, die 48–96 h nach der Herzoperation auftraten und mindestens 30 s dauerten. Die PMI-Werte von Patienten, bei denen POAF auftrat, wurden mit den Werten von Patienten verglichen, bei denen kein POAF auftrat.
UNASSIGNED: Patienten, bei denen POAF auftrat, wiesen höhere PMI-Werte auf (2549,3 ± 1077,1) als Patienten mit einem Sinusrhythmus (2248,1 ± 683,4; p < 0,01). Bei der multivariaten Regressionsanalyse stellten Alter (Odds Ratio, OR: 1,05; 95%-KI: 1,02–1,09; p = 0,01), linker Vorhofdurchmesser (OR: 1,05; 95%-KI: 1,03–1,09; p = 0,02), hochsensitives C‑reaktives Protein (hs-CRP; OR: 1,09; 95%-KI: 1,05–1,13; p < 0,01), EuroSCORE II (OR: 1,27; 95%-KI: 1,14–1,41; p < 0,01) und PMI (OR: 1,01; 95%-KI: 1,001–1,02; p < 0,01) unabhängige Prädiktoren eines POAF dar. In der Receiver-Operating-Characteristic(ROC)-Analyse war ein PMI ≥ 2286 Prädiktor für die Entwicklung eines POAF mit einer Sensitivität von 69% und einer Spezifität von 58% („area under the curve“, AUC: 0,66; p < 0,01).
UNASSIGNED: Zwischen präoperativ berechnetem PMI und POAF wurde ein signifikanter Zusammenhang festgestellt. Es wurde gezeigt, dass der PMI als Prädiktor für Patienten eingesetzt werden kann, bei denen ein hohes Risiko für das Auftreten eines POAF besteht.

Different qualitative and quantitative changes in platelets are involved in the pathophysiological processes in inflammatory bowel diseases (IBD): ulcerative colitis (UC) and Crohn\'s disease (CD). The aim of the study was to determine the diagnostic accuracy of Platelet mass Index (PMI) and other platelet parameters in assessment disease activity in patients with UC and CD. A cross-sectional, observational study consisted of 60 IBD patients (30 UC and 30 CD) and 30 healthy subjects (Control group). Patients were grouped according to disease activity into active and inactive (remission). Platelet count (PLC), Plateletcrit (PCT), Mean Platelet Volume (MPV), Platelet Distribution Width (PDW) and PMI were determined for all study participants. Receiver operating characteristic (ROC) curve and their corresponding areas under the curve (AUC) were used to determine diagnostic accuracy. Although PLC had the highest AUC (0.756) compared to PCT (AUC: 0.731), PDW (AUC: 0.722) and PMI (AUC: 0.724), they all had fair diagnostic accuracy in distinguishing active and inactive UC patients. Discriminatory accuracy of PLC was excellent (AUC: 0.909), PCT and PMI good to excellent (AUC: 0.809 and AUC: 0.893, respectively) and PDW fair (AUC: 0.789) in classifying CD patients as active and inactive. Platelet parameters are simple, routinely available biomarkers more useful for assessing disease activity for patients with CD than for patients with UC. Our results indicate, for the first time, that PMI may serve as a novel and simple marker in identifying whether IBD patients are in the active or inactive phase of the disease.

Neonatal thrombocytopenia is a common hematological abnormality that occurs in 20–35% of all newborns in the neonatal intensive care unit. Platelet transfusion is the only known treatment; however, it is the critical point to identify neonates who are really at risk of bleeding and benefit from platelet transfusion as it also has various potential harmful effects.
To investigate the prevalence and risk factors of neonatal thrombocytopenia and its relationship to intraventricular hemorrhage in the neonatal intensive care unit and to determine whether the use of platelet mass index-based criteria could reduce the rate of platelet transfusion.
Retrospective cohort study.
This study was conducted in the neonatal intensive care unit of a tertiary university hospital. The medical records of neonates in the neonatal intensive care unit with platelet counts <150×109/L between January 2013 and July 2016 were analyzed.
During the study period, 2,667 patients were admitted to the neonatal intensive care unit, and 395 (14%) had thrombocytopenia during hospitalization. The rate of intraventricular hemorrhage was 7.3%. Multiple logistic regression analysis showed that although lower platelet counts were associated with a higher intraventricular hemorrhage rate, the effects of respiratory distress syndrome, sepsis, and patent ductus arteriosus were more prominent than the degree of thrombocytopenia. Thirty patients (7%) received platelet transfusion, and these patients showed a significantly higher mortality rate than their non-platelet transfusion counterparts (p<0.001). In addition, it was found that the use of platelet mass index-based criteria for platelet transfusion in our patients would reduce the rate of platelet transfusion by 9.5% (2/21).
Neonatal thrombocytopenia is usually mild and often resolves without treatment. As platelet transfusion is associated with an increased mortality rate, its risks and benefits should be weighed carefully. The use of platelet mass index-based criteria may reduce platelet transfusion rates in the neonatal intensive care unit, but additional data from prospective studies are required.

BACKGROUND: Platelet mass index (PMI) is associated with platelet functionality. The aim of this study was to evaluate the role of PMI in predicting the severity of transient tachypnea of the newborn (TTN).
METHODS: Infants with gestational age ≥37 weeks and birthweight ≥2,000 g who were given nasal intermittent mandatory ventilation for TTN ≤6 h after birth were retrospectively enrolled in this study. PMI was calculated using the following formula: PMI = platelet count × mean platelet volume/103 (fL/nL). The study infants (n = 101) were divided into two groups according to the duration of tachypnea: ≤48 h (n = 45) and >48 h (n = 56).
RESULTS: The PMI and platelet count were significantly lower in the group with tachypnea duration >48 h than in the tachypnea duration ≤48 h group (P < 0.001 and P = 0.04, respectively). A negative significant correlation was noted between PMI and the duration of tachypnea (r = -0.43, P < 0.001). A PMI cut-off of 1,562 fL/nL can predict prolonged tachypnea (>48 h) with a sensitivity of 62.5%, specificity of 68.9%, positive predictive value of 71.4%, and negative predictive value of 59.6% (area under the curve, 0.682 ± 0.053; P = 0.002).
CONCLUSIONS: Lower PMI and lower platelet count are associated with longer duration of tachypnea in patients with TTN.

Retinopathy of prematurity (ROP) is a proliferative vitreoretinopathy resulting from vascular defect of the retina. The present study evaluates platelets, which are involved in VEGF storage, transport and release, and their functions with regard to the prognosis of the disease. The objective was to suggest a simple minimal invasive method that will facilitate the management of the disease and help clinicians in predicting the prognosis.
In this single center, retrospective, case-control study, we included a control group consisting of very preterm newborns (n = 83) at risk of ROP and a laser photocoagulation group including infants (n = 63) who received laser therapy during their follow-up examinations. The employed assessments included platelet counts and platelet mass index (PMI) which provide guidance in understanding platelet activity. In doing so, consideration was given to the first and second phases of ROP. The accuracy of prognostication was assessed with receiver operating characteristic analyses.
The study groups did not differ statistically significantly by platelet count during the first and second phases of ROP (p > 0.05) nor were the PMI measurements statistically significantly different between the study groups during the first phase of the disease (p > 0.05). PMI values of the study groups, however, differed significantly in the second phase of ROP (p < 0.05).
The present study found a significant difference between the two groups in PMI measurements which reflect increased VEGF levels during the neovascularization phase, which underlies the disease. This conclusion demonstrated that monitoring the PMI values in newborns at risk of ROP can be considered to be a minimally invasive method that by changing the retinal examination procedure in use today which is rather troublesome for both the physician and the newborn, can provide facilities in monitoring the disease for both the physician and the newborn.

Platelet mass index (PMI) is related to the platelet functionality. The aim of this study was to evaluate the correlation between PMI and the occurrence of various inflammation-related morbidities of prematurity, such as bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH) and sepsis in very low-birth weight (VLBW) infants.
This retrospective analysis of VLBW infants admitted to a level 3 neonatal intensive care unit from October 2012 and 2014, n = 330. Platelet mass was calculated and recorded on the day of birth and between 3 and 7 days (second measure) for each patient. Statistical analysis included analysis of paired samples t test and independent samples t test.
Among VLBW neonates, PMI values were lower in infants with ROP (p = 0.016), BPD (p = 0.002), IVH (p = 0.018) and NEC (p = 0.011) when compared with the control group in the second measurement.
In this study, we found that premature infants with BPD, NEC, ROP, IVH and sepsis had lower PMI levels in early postnatal life than infants without these diseases. This might be associated with the inflammatory process.