Topical Airway Anesthesia for Awake-endoscopic Intubation Using the Spray-as-you-go Technique with High Oxygen Flow

Summary

The topical anesthetic lidocaine was atomized using a high oxygen flow through the working channel of a flexible intubating endoscope to achieve topical airway anesthesia for awake endotracheal intubation. We prefer this modified spray-as-you-go technique for endoscopic intubation to classical bolus application because of higher patient satisfaction and better compliance.

Abstract

A patient's willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can jeopardize their spontaneous breathing, topical anesthesia of the airway is a popular technique. The spray-as-you-go technique represents one of the simplest opportunities to anesthetize the airway mucosa. The application of local anesthetic through the working channel of the flexible endoscope is a widespread practice for anesthetists as well as pulmonologists. There is neither need for additional devices nor special training as a pre-requisite to perform this technique. However, a known clinical problem is the coughing and gagging reflex that may occur when the liquid anesthetic strikes the airway mucosa and other sensitive structures like the vocal cords. This can be avoided by the use of oxygen applied through the working channel with the aim of fogging the local anesthetic into finer particles. Furthermore, the oxygen flow provides a higher oxygen supply and contributes to a better view, dispersing mucus secretions and blood away from the lens. Using an atomizer with a high oxygen flow of 10 L/min we maximized these benefits, caused less coughing and had more satisfied and therefore cooperative patients. Possible, but very rare complications of using oxygen flow including gastric insufflation, organ rupture or barotrauma did not arise. We attribute the complication-free use of high oxygen flow to the design of the set, which permits flow and pressure release.

Introduction

Topical anesthesia of the airway for awake intubation is generally recommended to improve patient comfort, which will help make the procedure a success. The spray-as-you-go technique with high oxygen flow is a simple and safe concept that is finding a high level of acceptance among patients. The atomization of the local anesthetic by oxygen at a flow rate of 10 L/min results in less stimulation of the cough and gag reflex.

Faced with negative feedback from several patients, we decided to refine the standard institutional spray-as-you-go technique. This classical bolus application of local anesthetic consisted of two injections, each of 5 mL....

Protocol

All procedures were approved by the ethics committee of the medical association of the State Rhineland-Palatinate and performed in accordance with the Declaration of Helsinki.

1. Atomizer⁴

1. Remove the set from package. Inspect the product to ensure there is no damage.
   NOTE: The device is intended for one-time use. Please refer to the instructions for use for further information about storage and supply (see Materials and Equipment Table).

2. General Preparation of the Patient

1. Administer premedication, e.g. Lorazepam 1 - 2.5 mg the evening before and/or 2 - 4 mg 1 - 2 h before t....

Results

We performed awake flexible endoscopic intubation using the presented topical anesthesia technique in 48 patients. We succeeded in intubating all patients except one, who suffered from a stenosing tumor of the pharynx, which made it impossible to advance the tube.

The quality of awake intubation comfort was evaluated by patients, anesthetists and nurses using an 11-point visual analog scale (VAS) from 0 = not unpleasant to 10 = .......

Discussion

Here we demonstrate topical anesthesia using an atomizer with high oxygen flow for awake-endoscopic intubation. The first study to evaluate the atomizer technique compared it with classical boluses of topical anesthesia via the working channel of the flexible intubating endoscope⁵. Patients in the atomizer group evaluated their level of comfort as better than those in the control group and experienced fewer coughs and distinct coughing episodes. In addition, the atomizer technique was faster and less local ane.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Lidocaine 10% pump spray	e.g. AstraZeneca
Opiod for i.v. administration			Any opiod can be used. We prefer either Sufentanil or Fentanyl
Enk Fiberoptic Atomizer Set	Cook Medical	C-EFNS-100	The Enk Atomizer set is currently not available from Cook Medical
Lidocaine 2%	e.g. AstraZeneca
Intubation endoscope	e.g. Karl Storz Endoscope		We prefer a fibrescope with an outer diamter of 5 mm and a working channel with a diamter of 2 mm
Endotracheal tube	e.g. Rüsch		Size of the endotracheal tube needs to be adjusted to the patient. We prefer a ID 6.5 mm for nasal approach and ID 7.0 mm for oral approach
Anesthetic drug, e.g. Propofol 1%	e.g. AstraZeneca