A prospective comparative study of laryngoscopic vision of vocal cords in ramp position and conventional sniffing position during endotracheal intubation

After obtaining Ethics Committee approval and written informed consent from the patients, those patients included in ASA physical class I-II in the age group of 18-60 years of either sex undergoing elective surgery under general anesthesia requiring endotracheal intubation is selected for the study.

Pre anaesthetic evaluation of the patient posted for surgery will be conducted on the day before surgery and pre-anesthetic orders will be given. The patient’s BMI, Mallampati Score, Thyromental distance and Neck circumference will be noted. The patients will be divided into two groups, Group S and Group R.

On the day of the surgery, inside the operation theatre, monitoring of Oxygen saturation, heart rate, non invasive blood pressure will be done. A patent IV cannula will be provided and IV fluids will be started for fluid management. Patient will be preoxygenated with 100% oxygen for 3 minutes, premedicated with Inj MIDAZOLAM 0.01mg/kg, Inj GLYCOPYRROLLATE 0.01 mg/kg and Inj FENTANYL 2mg/kg. Patient will be induced with Inj PROPOFOL 2mg/kg and muscle relaxant Inj VECURONIUM 0.1mg/kg will be given. For the first group (Group S), laryngoscopy will be done in “sniffing position” first and Cormack Lehane grade will be noted, after which table position will be changed to get a “ramp position” measuring 500+/-60 angle using protractor, the end point being  the external auditory meatus and sternal notch are in horizontal line. This will be confirmed by using the Scale Ampoule Method where a transparent ampoule will be plastered to a long metallic scale and held between EAM and sternal notch. The table elevation and head end flattening, after the initial lift to 50 degree will be adjusted such that the bubble in the ampoule comes to lie in the centre. Modified  Cormack lehane grading will be noted in this position again. For the next group (GroupR) , laryngoscopy will be done in RAMP position first and in sniffing position later. The endotracheal tube of appropriate size will be inserted and during the process the ease with which tube is passed will be assessed, by assessing the need for any external manuevres or use of adjunct devices like style or bougie. The position of the ET tube will be confirmed with 5 point auscultation and capnography.

In case the intubation is difficult in either of the positions, a switch will be made to the other position. If intubation is still difficult after change in position, call for help and difficult irway algorithm will be initiated assuming  an unanticipated difficult airway scenario.