This study was prospective, and it continued to follow up until the need for respiratory support was reduced. At El-Gamaaya El-Sharaya Hospital, 6 October city, Egypt, it was carried out on 120 neonates having RD who were receiving care in the NICU. Ethics committee approval was obtained by research ethical committee October 6 University, Egypt. Prior to enrolment, patients’ guardians granted informed consent after being apprised of the study’s purpose. Participants had the privilege to continue participating in the research at any time and maintain their confidentiality about all study data.

Inclusion criteria

Neonates who exhibited signs of RD after birth (such as tachypnea, chest retractions, or grunting) which necessitated respiratory assistance in the form of mechanical ventilation or bubble continuous positive airway pressure (CPAP) or head box or nasal O2 therapy and hemodynamically stable.

Utilizing the Silverman Andersen respiratory severity score for newborns, respiratory impairment was reviewed. It considers five aspects of respiratory exertion and offers an ultimate score, score 0= no RD, 1–3= mild RD, 4–6 = moderate RD, >6 = impending respiratory failure and score 10= severe RD (Fig. 1) [10,11,12].

Fig. 1

The Silverman Andersen Respiratory Severity Score (RSS) evaluates five parameters of work of breathing and assigns an overall score with a patient breathing comfortably a “0” and a patient in severe respiratory distress a “10”

Exclusion criteria

Any neonate with congenital heart disease (ECHO cardiography was done for all our patients to exclude patent ductus arteriosus), congenital anomalies, hemolytic disorders. Neonates with early onset sepsis either clinically or proved by positive blood culture, positive C reactive protein, leucopenia or leucocytosis with shift to the left or bandemia. Thrombocytopenia is a work of sepsis and none of our cases had thrombocytopenia.

The following was implemented to all participants: collecting a comprehensive medical history with an emphasis on gestational age (GA), gender, mode of delivery, birth weight, family history, consanguinity. Clinical examination including grading of RD, demand for oxygen supplementation, and length of hospital stay was collected for all patients.

Based on evidence from previous similar studies, we used epi-calculator 2000 to calculate the sample size of this comparative study. Assuming 80% power and 0.05 level of significance, a total sample size of 120 participants was calculated.

Laboratory investigations

All participants’ blood samples were drawn for a complete blood count (CBC); platelet indices were examined upon entrance to the NICU, and subsequently verified after reduction of respiratory support.

Applying the following equation, PMI was calculated: (PMI = [Platelet counts] × [mean platelet volume/103]) (fL/nL) [13].

Sample collection

Venipuncture was performed to obtain 2 ml of venous blood, which was then placed in tubes containing tripotassium-ethylenediaminetetraacetic acid (EDTA) to avoid coagulation. Within 30 min of being collected, samples were swiftly shipped to the lab for processing. The automated cell counter (Sysmex KX-21N) was used to analyze the obtained EDTA samples in order to get all PLT indices: MPV expressed in femtolitre (fl), PCT expressed in percentage (%), platelet count (PC) calculated in cubic millimeter (*1000/mm3), PDW and PLCR measured in percentage (%).

Statistical methods

Version 28 of SPSS’ statistical software program was used to examine the data. Utilizing the Kolmogorov-Smirnov single-sample test, the data’s normalization was evaluated. Numbers and percentages are used to represent qualitative data. Mean and standard deviation were used to depict quantitative parameters. The comparison between results before applying respiratory support and after elimination was done using Wilcoxon test. The Mann-Whitney test was used to contrast the two sets of numerical data, and the Kruskal-Wallis test by post hock test will be employed for pairwise comparison when considering more than two participants. Spearman correlation was used to correlate continuous data. To identify the ideal cut-off value, receiver operator characteristic (ROC) curves were applied. Significance was defined as (p ≤ 0.05).