Inclusion Criteria:
1\. Male or non-pregnant female over 18 years who are undergoing surgery and using sevoflurane as the anesthetic agent and with Mallampati score III or IV
2\. Patients with at least one of the below criteria:
1. Anatomic
* micrognathia - small mandible
* macroglossia - large tongue
* short or fixed neck
* anterior vocal cords
2. Trauma - neck or face
3. Burns - airway edema
4. Infections - edema
* Retropharyngeal abscess
* Submandibular abscess
* epiglottitis
* laryngotracheobronchitis (croup)
5. Neoplasms; e.g., laryngeal tumors
6. Rheumatoid arthritis - temporomandibular joint (TMJ) immobility
7. Diabetes mellitus
8. Waxy skin - palm test
9. Decreased functional residual capacity (FRC) - rapid desaturation (due to displaced diaphragm, increased closing capacity and small airway closure, increased oxygen consumption)
10. airway closure in supine position
11. Morbid obesity (body mass index \[BMI\] \>35)
12. Airway edema
13. Laryngospasm
14. Edentulous patients - indent cheeks.
3\. Patients willing to sign informed consent
Exclusion Criteria:
1. Patients with present use of opioids and/or narcotic dependent.
2. Patients with known sensitivity to sevoflurane or to other halogenated agents.
3. Patients with known or suspected genetic susceptibility to malignant hyperthermia.
4. Alcohol addictive patients.
5. Patients with Renal insufficiency (baseline serum creatinine greater than 1.5 mg/dL)
6. Patient is a pregnant or breastfeeding female
