Platelet mass index and prediction of severity of transient tachypnea of the newborn

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/10 3 ( 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 .