BASKA Mask in Otologic Surgery in Lateral Position

This study aims to evaluate the Efficiency and safety of BASKA mask ventilation in comparison with endotracheal intubation during otologic surgery performed with the head and neck in the lateral position. The primary outcome will be the intraoperative peak inspiratory pressure (PIP). Secondary outcomes will be intraoperative lung mechanics, oropharyngeal leak pressure (OLP), ventilation score, fiberoptic glottic view score, and perioperative adverse effects.

The laryngeal mask airway (LMA) was invented in 1981 by Dr Brain Because of its advantages, LMAs are increasingly used as a substitute for endotracheal tubes in a variety of surgical situations requiring general anesthesia. With the appearance of various new LMAs that address the limitations of the classic model, not only has their use in selective operations increased, but the indications for LMA have also grown LMAs can be inserted into the hypopharynx easily without laryngoscopy and neuromuscular blocking agents, and they can also be removed from the patient's mouth quickly. Decreasing airway irritation during surgery results in fewer hemodynamic changes and airway accidents from anesthesia and enables wakeup with less coughing and bucking, which could result in less ossicular replacement prosthesis displacement .

In middle ear/mastoid procedures, because the operation involves the temporal bone, including the surrounding normal nerves and blood vessels, improper manipulation can lead to complications such as facial paralysis; therefore, the operation needs to be performed carefully. Compared to endotracheal intubation, LMAs have little effect on middle ear pressure . These advantages make anesthesiologists prefer LMAs during otologic surgery. In addition, since LMAs can reduce the response to upper airway stimulation, they can be used as an airway device during surgery requiring facial nerve monitoring without the use of muscle relaxants .

However, the points of contention and primary disadvantages of the use of LMA are the reduced levels of airway protection, the increased risk of gastric insufflation, the difficulty of insertion, partial upper airway obstruction and the possibility of dislocation during the procedure . To expose the operative field, otologists usually require the patient's head be rotated 60°\~90° to the healthy side. Some studies have reported that the head and neck position can affect the sealing and ventilation functions of LMAs and the fiberoptic view .

The Baska mask (Logikal Health Products PTY Ltd., Morisset, NSW, Australia) is a supraglottic airway device introduced in 2012 with many innovations that might be expected to overcome these derangements . First, its' non-inflatable cuff is continuous with the central channel of the device and automatically inflates during positive pressure ventilation in response to the increased inflation pressure. This inflation produces an oropharyngeal leak pressure higher than that produced by other LMAs, enabling more effective ventilation. Second, it has an esophageal drainage inlet and side channels that comprise an efficient pharyngeal drainage system which facilitates aspiration of gastric contents, thereby reducing the risk of gastric overinflation and pulmonary aspiration. Third, a strong integrated bite-block that acts as a safeguard against obstruction of the Baska mask.

In this study, the hypothesis is that these modifications might enable the Baska mask to become a reasonable and safe alternative to the endotracheal intubation in during otologic surgery performed with the head and neck in the lateral position.

Eligibility Criteria:
Inclusion Criteria:

1. Age group 18 - 60 years old.
2. Both genders.
3. Undergoing general anesthesia for ear surgeries in the lateral neck position (60-90 degrees) in whom BASKA mask can be a suitable device for airway management

Exclusion Criteria:

1. Patient refusal,
2. History of cardiac or respiratory disease, psychological disorders,
3. High risk of regurgitation or aspiration based on a history of diabetes, hiatus hernia, gastroesophageal reflux, and obesity,
4. neck pathology,
5. Predicted difficult airway (history of difficult airway, mouth opening \<2.5cm, Modified Mallampati class III/IV, thyro-mental distance \<6.5cm or cervical spine pathology),