**Table 1.**

*Update on Critical Issues on Infant and Neonatal Care*

**2.1 Clinical signs and symptoms**

Early diagnosis is of a high importance due to available management methods [15, 16]. A combination of clinical signs and different modalities such as chest radiographies and laboratory tests are needed for diagnosing NRDS [14].

There are a wide range of clinical signs from nasal flaring and cyanosis to substernal and intercostal retraction, tachypnea and grunting [16]. A risk assessment tool called "Clinical Risk Index for Babies" (CRIB) is used to estimate the need for admission of infants in NICU [17]. Different factors such as gestational age, birth weight and base excess during the first 12 hours of life, fraction of inspired oxygen and presence of congenital malformations are considered in this assessment

Arterial oxygen pressure (PaO2) is a marker for diagnosis of NRDS. PaO2 less than 50 mmHg with cyanosis in room air or need for supplementary oxygen for maintaining O2 level above 50 mmHg are indicators for NRDS [14]. Metabolic and

Gastric aspirate shake test (GAST) is another laboratory measure with reported

Recently published studies have mentioned a new factor for early detection and prediction of NRDS in premature infants. Transforming growth factor β1 (TGF-β1) is a cytokine, which has the responsibility for regulating and differentiating different cell lines [20, 21]. These studies have marked the role of TGF-β1 in development of various acute and chronic lung injuries and concluded that this factor can be used as a diagnostic and prognostic one [22]. The same role has been considered for interleukin-6, which is a glycoprotein secreted mostly from T cells and mononuclear

Previous studies have reported a remarkable diagnostic value for chest radiographs [25]. Features such as reduced lung expansions, air bronchograms and dilated bronchioles can be seen in NRDS [15]. In addition to diagnostic use, chest radiographs have another application to confirm endotracheal tube position. Premature infants receive continuous positive airways pressure (CPAP) for augmenting oxygenation in addition to simplifying intra-tracheal administration of surfactants [14]. The precise adverse effects of radiation have not been yet determined; however, some efforts are being done to find an alternative method for chest

Previously, lung ultrasound (LUS) was not used for infant chest imaging due to interference of air levels. This modality has its own potential adverse effects including thermal and mechanical tissue damage [27, 29]. Recently, lung ultrasound

sensitivity of 100% and specificity of 92% for diagnosis of NRDS [18]. GAST identifies presence or lack of surfactant in the gastric fluid aspirates [19].

respiratory acidosis are measured through a blood sample.

macrophages causing inflammatory reactions [23, 24].

**2. Diagnosis**

(**Table 1**).

**2.2 Laboratory tests**

**2.3 Chest radiographs**

radiography [26–28].

**2.4 Ultrasound**

**20**

*CRIB score.*

has been widely used as an accurate diagnostic tool according to published clinical studies [4, 7, 16, 30–34]. Lack of normal air-filled levels and presence of fluid level is a diagnostic clue for NRDS.

A meta-analysis of six studies comparing LUS to chest x-ray for diagnosing NRDS reported a high diagnostic sensitivity (97%) and specificity (91%) for LUS [35]. They have also reported that transthoracic technique is superior to transabdominal approach for diagnosing NRDS.

On the other hand, some researchers believe that lung ultrasound can be helpful only as a complementary diagnostic tool rather than a diagnostic method [36]. They have mentioned in a letter-to-editor that only chest radiographs and CT scan can be reliable for diagnosing neonatal respiratory distress syndrome.
