The goal of this prospective, observational study is to identify predictors of difficult mask ventilation, direct laryngoscopy and intubation in pediatric patients scheduled for elective surgery and to determine their incidence. As a final goal, the investigators will try to define new scoring system for difficult airway prediction. Participants will be pediatric patients age infant till school age. Participants will have their airway assessed one day before surgery by taking anthropometric measurements of face and neck. After iv anesthesia induction and application of muscle relaxant, the investigators will assess difficulty of face mask ventilation by using grading from 0-4. Direct laryngoscopy will be performed with Macintosh blade and experienced anesthesiologist will determine Cormack - Lehane score as well as intubation difficulty score (IDS).

Participants will be divided into groups: up to 1 yrs of age, 1-2.9 yrs, 3-4.9, 5-6.9, and 7 yrs and older.

The investigators will test predictive value, sensitivity and specificity of anthropometric parameters used for airway assessment in pediatric patients, as well as gender, age, BMI, ASA score.

Anatomical parameters that will be measured the day before surgery: chin, inter - incisor gap, hyomental distance (HMD), hyoid - thyroid distance (HT), neck circumference, neck length, neck extension, lower lip to chin distance (LCD), tragus to chin distance (TMA), thyromental distance (TMD), sternomental distance (SMD).

Mallampati test will be performed in children older than 5 years and best oropharyngeal view (BOV) will be determined for younger children. Colorado Pediatric Airway Score (COPUR) will be calculated.

All patients will be premedicated with midazolam 0.5 mg/kg orally, 30 minutes before intervention or 0.1 mg/kg iv. Anesthesia induction will be intravenous: thiopentone 5 mg/kg or propofol 2.5 mg/kg, fentanyl 3 mcg/kg and non depolarizing muscle relaxant rocuronium 1 mg/kg or cis-atracurium 0.15 mg/kg. Face mask ventilation will be quantified as grade 0-4. Anesthesia maintenance will be intravenous or inhalatory depending on anesthesiologists decision. Patients will be intubated with Macintosh blade in the supine position, without additional elevation of occipital part of the head. Difficult laryngoscopy is defined as CL grade III and IV and they predict difficult endotracheal intubation. Intubation difficulty score will be used to asses intubation. Intubation difficulty will be defined by IDS - intubation difficulty score > 5.

Standard procedures will be performed in case of difficult mask ventilation and intubation.

Inclusion Criteria:

• Pediatric patients from one month to 14 years old scheduled for elective surgery in general endotracheal anesthesia.

Exclusion Criteria:

• Congenital syndromes which include difficult airway (Pierre Robin, Goldenhar syndrome, Treacher Collins syn, Down syn, Edwards, Arthrogryposis, Apart syn etc.), craniofacial dysmorphia, ENT, maxillofacial and cardiac surgery patients, patients with resent respiratory infections

Patient will be divided in 5 groups according to age: infants, children from 1 - 2,9 years, 3 - 4,9 years, 5 - 6,9 years and older than 7 years.