The Efficiency of Different Oropharyngeal Airways as a Conduit for Fiberoptic Intubation. Comparative Study

The study was conducted in Kasr Alainy hospital, faculty of medicine, Cairo University.

After approval of ethical committee and informed written consent from each patient, 60 patient aging above 18 years, ASA I-II , with Ganzouri airway score <4 and undergoing elective surgeries under general anesthesia were included in the study.

Patients were randomly allocated into three equal groups:

Group M (GM) (n=20 patients): patient was intubated using LMA MADgic airway. Group W (GW) (n=20 patients): patient was intubated using modified Williams airway.

Group G (GG) (n=20 patients): patient was intubated using modified Guedel's airway.

Randomization was performed by random computer allocation with numbered closed opaque envelopes.

The study was performed by expert anesthesiologist in FOB intubation. In the preparation room, all patients was cannulated with a 20 gauge venous cannula and 0.02mg/kg Midazolam was given. Patient transferred to the operating room and was monitored with non-invasive blood pressure, pulse oximetry and ECG. After preoxygenation using a facemask for 5 min, induction of anesthesia was done with 2mg/kg propofol, 1 μg/kg of fentanyl and 0.6 mg/kg of atracurium.

After loss of consciousness the selected airway according to group randomization was inserted into the mouth (size selection and technique of insertion according to manufacturer instruction). Time of insertion defined as the time, in seconds, from touching the patients' mouth with the airway until capnographic confirmation of ventilation by facemask. The ease of insertion was determined by number of attempts of airway insertion. Adaptation of the airway was determined by adequacy of ventilation, fitness to the oral cavity and appearance of successive ETco2 waves.

Manual positive-pressure ventilation was then started with 100% oxygen and 1-1.5% isoflurane through the facemask for 3 min until complete muscle relaxation was confirmed (when train-of-four count becomes zero).

Loaded FOB was inserted for intubation through the airway, laryngeal view grade was recorded (LVG) using Brimacomb and Berry scale; thereafter, the fiberscope was advanced into the trachea to a level just above the carina and the tracheal tube was railroaded over it.

Tracheal intubation could be facilitated by tube rotation, jaw thrust, neck extension or flexion and adjustment of the airway was allawed and was recorded. The intubation time was recorded ; that is, the time from cessation of manual ventilation using a facemask until restarting of ventilation through the tracheal tube.

The airway was removed except the LMA MADgic airway which was removed before ETT insertion. The ease of airway removal was evaluated by the anesthesiologist.

Inclusion criteria

• ASA physical state I-II Ganzouri airway score less than 4

Exclusion criteria

• ASA physical state III-IV. Patients with Ganzouri airway score more than 4. Patients with risk of aspiration of gastric content. Any anatomical abnormalities or iatrogenic injuries that invalidate Ganzouri airway score.