Comparative evaluation of tracheal intubation using airtraq and intubating laryngeal mask airway with cervical spine immobilisation

In our study we endeavoured to compare Airtraq with ILMA for trachealintubation in simulated cervical spine injury patients with cervical spineimmobilisation using MILS. Following Institutional Review Board approval andwritten informed consent, 100 adult patients between 18 to 60 years of agescheduled for elective surgery under general anesthesia were randomly allocatedto one of the two groups (Airtraq group or ILMA group), 50 in each group. Patientswith cervical spine or any oral pathology, airway distortion, mouth openingless than 3cm, pregnant patients were excluded from tthe study.

Standard anaesthesia technique was followed forall the patients. Inj. fentanyl 2 µg/kg IV was given. After 2mins,anaesthesia was induced  withInj.propofol 2 mg/kg IV. Adequacy of ventilation was assessed and musclerelaxation was achieved with Inj. vecuronium bromide 0.1mg/Kg IV. Patient wasventilated with 100% O2 and isoflurane≤1%  for 3 mins. Subsequently the pre-checked andprepared airway device (Airtraq or ILMA) of appropriate size was insertedaccording to the standard technique after applying MILS. Hemodynamic parameters (HR,NIBP) was recorded just before device insertion and then every minute till 10 mins after intubation.

The Primary outcome variable was time taken forintubation and it was taken from holding the airway device for insertion to thefirst square shaped capnograph (T1+T2). The number of attempts for insertion ofairway device were noted. Pulse rate and mean arterial pressure were recordedafter insertion of airway device in both the groups every minute for the firstten minutes. Complication like trauma to lip/tongue/oral mucosa and presence ofblood on device after removal were noted. Statistical analysis of the data wasdone using the SSPS software version 22.0. P<0.05 was consideredstatistically significant.

Therewere no statistically significant differences in demographic characteristicsbetween the groups. The mean time taken for the insertion of the airway devicein the ILMA group was 1.43 ± 0.61 mins and in the Airtraq group was 0.21 ± 0.11mins. The difference is statistically significant. Even though the time takenfor intubation in the ILMA group is significantly longer than the Airtraqgroup, the uninterrupted ventilation maintained during intubation in the ILMAgroup ensured adequate oxygenation. In the ILMA group it was seen that airwaydevice was inserted in first attempt in 88% patients and a second attempt wasneeded in the remaining 12%. In the Airtraq group, airway of all patients(100%) was successfully secured in first attempt and this difference was foundto be statistically significant (p=0.027). The intubator found intubationusing Airtraq easier than intubating with ILMA as graded by the Likert scale (4 vs 3 in Airtraq group vs ILMA group). In the hemodynamic parameters, we found that baselinevalues for both heart rate and MAP in both the groups were similar without anysignificant difference. However, when the heart rate was compared at differenttime frames from the insertion of the airway devices i.e. at 2, 3, 4, 5, 6, 7,8, 9, and 10 minutes of insertion it was found that the mean difference betweenboth the groups was statistically significant. It was observed that the heartrate in Airtraq group is more controlled and stable as compared to the ILMAgroup. We observed that there was immediate rise in MAP (at 1, 2 and 3 mins) inboth the groups after insertion of the airway device which was more in the ILMAgroup as compared to the Airtraq group, though this difference was notstatistically significant. This could have been due to the sympatheticstimulation seen during airway manipulation.Subsequently, when the MAP wascompared at time frames of 4, 5, 6, 7, 8, 9 minutes after insertion of the airway device in both the groups, thedifference was statistically significant and the readings were found to be more controlled in the Airtraq group ascompared to the ILMA group. Blood stain on the ILMA device after removal wasseen in 2 patients as compared to none seen in the Airtraq group. Thedifference was statistically not significant.

From our study, we suggest the use of Airtraq indifficult airway scenarios with limited/ restricted neck movements. Decreasedhemodynamic response to intubation using Airtraq makes it a promising device inpatients with CAD and hypertension.