After approval from the ethics committee, patients in the age group of 3 months to 18 years scheduled for routine surgical procedure under general anaesthesia with endotracheal intubation using airtraq (AT) will be observed during the period of the study. Any co-existing medical disease, associated congenital anomalies and airway problems and will be noted. Written valid informed consent will be taken from the respective parent or guardian. If the child can understand the nature of procedure, he or she will be explained about the study and assent will be taken.

All children will receive general anaesthesia as per routine protocol followed in various operation theatres in LTMGH, Sion. This usually comprises of:

• Preoperative starvation as per ASA fasting guidelines 2011
• Establishment of monitoring like electrocardiogram, pulse oximetry, capnography and non invasive blood pressure measurement
• Premedication in form of antisialogogue, sedatives and analgesic
• Either Intravenous or Inhalational induction
• Checking of adequate depth of anaesthesia
• Confirmation of adequacy of ventilation without gastric insufflation
• Administration of neuromuscular blockade
• Intubation using AT laryngoscope by experienced anaesthesiologists as per manufacturer’s instructions (appendix B)
• Sizes of AT laryngoscope used ( appendix C)
• Confirmation of proper endotracheal intubation by observation of chest expansion, auscultation of bilateral breath sounds and square wave capnogram

 Following parameters will be assessed

 1. Percentage of glottis opening (POGO) score:  denotes visual estimation of laryngeal opening in score of 0% to 100%. (appendix A)

A POGO score of 100 = full visualisation of larynx from the interarytenoid notch to anterior commissure of the vocal cords; 0 = none of the glottis opening is seen.

 2. Visual analogue scores (VAS) for field of view :  0 to 10 -point scale. 0 = poor, 10 = excellent

 3. Time to best view (TTBV):  time interval between blade entry past the lips and the laryngoscopist’s verbal declaration that the best view for endotracheal intubation is achieved.

 4. Time to intubation (TTI): time interval between blade entry past the lips and the  appearance of first upstroke of the end-tidal CO2 tracing.

 5. Visual Analogue Scale(VAS) for ease of use : 0 to 10 -point scale. 0 = poor, 10 = excellent

Failed attempts, if any will be noted.

Failed attempt is considered when:

1. Inability to pass endotracheal tube within 60 seconds of AT blade entry past the lips
2. Abandoning the intubation attempt due to decrease in oxygen saturation < 94%
3. Change of premounted endotracheal tube

In our set up more than two intubation attempts with any device are not allowed.

Failed intubation is considered when successful intubation with airtraq is not possible.

Difficulties encountered e.g. anterior or posterior impingement of ET tube; loss of visualization due to “fogging” or “red-out” will be noted.

Optimization manoeuvres required (if any) will be noted.

  Commonly used optimization manoeuvres are:

·         repositioning the head or the need for a second assistant to aid tracheal intubation

·         use of external laryngeal manipulation

Complications associated with laryngoscopy-intubation, if any will be noted

STATISTICAL ANALYSIS

Data which are normally distributed will be presented as means ± standard deviation (M ± SD) for continuous variables. Data which is not normally distributed will be presented as median with interquartile range (median with IQR).

A subgroup analysis will be done depending on the size of the AT used. Any difference between the parameters will be studied using ANOVA test. Any significant difference in the parameters in individual group will be compared using unpaired t test. Categorical data like failed attempts, difficulties encountered in each subgroup will be studied by using Chi square test or Fisher’s exact test.