Assessment of Airway in Patients With Acromegaly for Predicting Successful Tracheal Intubation

Overview

Acromegaly is associated with increased risk of difficult intubation and its management. The overall incidence of difficult intubation in patients suffering from acromegaly is four to five times more than those without acromegaly.The difficult intubation scenario in these patients can be managed by various methods ranging from awake fiberoptic intubation to tracheostomy. Difficult tracheal intubation accounts for 17% of respiratory-related injuries and results in significant morbidity and mortality in general population. In patients with acromegaly, inability to mask ventilate or intubate can lead to 28% of all anesthesia related deaths. Therefore, the need and importance of airway assessment in patients with acromegaly cannot be overemphasized. Various tests of airway assessment have to be used to assess difficult airway and tracheal intubation in acromegalics. The investigators aim to assess the various tests of airway assessment affecting the outcome of patients with acromegaly undergoing pituitary surgery and identify which was best suited.

All the patients of either gender, diagnosed as a case of acromegaly scheduled for pituitary surgery will be enrolled. This observational study will be conducted over a period of 3 years. A written informed consent will be taken from all the patients. The clinical diagnosis will be made on the basis of growth hormone (GH) levels and magnetic resonance imaging (MRI) findings. All patients will be evaluated preoperatively, a day before surgery by an independent observer. Airway assessment for difficult intubation will be performed using Modified Mallampati classification in sitting and supine position followed by mouth opening, upper lip bite test, measurement of thyromental, thyrohyoid, sternomental and hyomental distance. Next the length of upper incisors, presence of receding mandible and neck movement will be checked. An associated history of OSA will also be taken in to account for assessing the difficult intubation followed by OSA grading in acromegalic patients posted for pituitary surgery. In situation of difficult tracheal intubation the fiberoptic intubation would be the preferred choice, which is a gold standard. General anesthesia will be induced with fentanyl 2µg/kg, propofol 2 mg/kg and rocuronium 1mg/kg. After 90 seconds of mask ventilation, laryngoscopy will be performed with an appropriate sized Macintosh laryngoscope and thereafter Cormac lehane grading will be noted. External laryngeal manipulation (ELM) if carried out will be noted. A standard anesthesia protocol will be followed. After completion of the surgery, neuromuscular blockade will be reversed with neostigmine 0.05mg/kg and glycopyrrolate 0.01mg/kg intravenously. Once the patient follows the verbal command and respiratory parameters are satisfactory, endotracheal tube will be removed. All patients will be shifted to neurosurgical ICU for observation and supportive management.