Related Experiment Video
Updated: May 28, 2026

Topical Airway Anesthesia for Awake-endoscopic Intubation Using the Spray-as-you-go Technique with High Oxygen Flow
Published on: January 13, 2017
Subcutaneous dissociative conscious sedation (sDCS) an alternative method for airway regional blocks: a new approach
1Department of Anesthesiology, Imam Khomeinee Medical center, Tehran University of Medical Sciences, Iran. mihanjavid@yahoo.com.
Background:
Predicted difficult airway is a definite indication for awake intubation and spontaneous ventilation. Airway regional blocks which are commonly used to facilitate awake intubation are sometimes impossible or forbidden. On the other hand deep sedation could be life threatening in the case of compromised airway.The aim of this study is evaluating "Subcutaneous Dissociative Conscious Sedation" (sDCS) as an alternative method to airway regional blocks for awake intubation.
Methods:
In this prospective, non-randomized study, 30 patients with predicted difficult airway (laryngeal tumors), who were scheduled for direct laryngoscopic biopsy (DLB), underwent "Subcutaneous Dissociative Conscious Sedation" (sDCS) exerted by intravenous fentanyl 3-4ug/kg and subcutaneous ketamine 0.6-0.7 mg/kg. The tongue and pharynx were anesthetized with lidocaine spray (4%). 10 minutes after a subcutaneous injection of ketamine direct laryngoscopy was performed. Extra doses of fentanyl 50-100 ug were administered if the patient wasn't cooperative enough for laryngoscopy.Patients were evaluated for hemodynamic stability (heart rate and blood pressure), oxygen saturation (Spo2), patient cooperation (obedient to open the mouth for laryngoscopy and the number of tries for laryngoscopy), patient comfort (remaining moveless), hallucination, nystagmus and salivation (need for aspiration before laryngoscopy).
Results:
Direct laryngoscopy was performed successfully in all patients. One patient needed extra fentanyl and then laryngoscopy was performed successfully on the second try. All patients were cooperative enough during laryngoscopy. Hemodynamic changes more than 20% occurred in just one patient. Oxygen desaturation (spo2< 90%) didn't occur in any patient.
Conclusions:
Subcutaneous Dissociative Conscious Sedation (sDCS) as a new approach to airway is an acceptable and safe method for awake intubation and it can be suggested as a noninvasive substitute of low complication rate for regional airway blocks.
Registration Id In Irct:
IRCT201012075333N1.
Related Concept Videos
Local Anesthetics: Clinical Application as Intravenous Regional Anesthesia
One of the advantages of...
Local Anesthetics: Clinical Application as Spinal Anesthesia
Local Anesthetics: Clinical Application as Surface, Infiltration, and Conduction Block Anesthesia
Parenteral Anesthetics: Overview
Depolarizing Blockers: Pharmocokinetics
Local Anesthetics: Clinical Application as Epidural Anesthesia
Since epidural anesthetics can be infused through an epidural catheter, all types of drugs, including short-acting ones, can be administered. Chloroprocaine and lidocaine are examples of short and long-duration anesthetics, respectively. Bupivacaine...

