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 (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.