retromolar intubation

RETROMOLAR INTUBATION

DR MAYURI GOLHAR

INTRODUCTION

• Patients with panfacial trauma require specific considerations for securing airway intraoperatively.

• The necessity of intraoperative restoration of dental occlusion by intermaxillary fixation (IMF) makes the presence of oral endotracheal tube unfeasible.

• Nasotracheal intubation, an alternate technique of securing airway ,but is contraindicated in certain conditions –

fracture of base of skull, fracture of naso-orbital-ethmoid complex because of complications like intracranial intubation, meningitis, epistaxis and sino nasal infection.

• In such circumstances, submento-tracheal intubation has been used successfully for securing airway perioperatively.

• Submento-tracheal intubation avoids the need of short-term tracheostomy and it’s associated complications.

• However,retromolar intubation is a non-invasive technique of securing airway in patients with panfacial trauma, avoids both submento-tracheal intubation and tracheostomy.

--PART 1--– STANDARD RETROMOLAR

INTUBATION TECHNIQUE

TECHNIQUE

• Orotracheal intubation is done initially with a flexometallic tracheal tube using standard general anaesthesia technique.

• The aim is to place the orotracheal tube in the retromolar space i.e. space behind the last upper and lower erupted molar teeth.

2) The orotracheal tube is grasped with gloved fingers and is placed into the retromolar space

The tube is then fixed by a wire ligature to the molar/premolar tooth along the upper or lower maxilla . The wire ligature is the same that is used for IMF. It fixes the retromolar-tracheal tube with the tooth in a “figure of eight” fashion

• Restoration of adequate dental occlusion by IMF is the important step prior to surgical fixation of fracture segments by plates and screws.

• At the end of surgical procedure, wire IMF is opened resulting in adequate mouth opening.

• The wire ligature around the reinforced tracheal tube is removed and the retromolar tracheal tube is converted back to orotracheal tube. Subsequently, trachea is extubated by the standard method.

• In the ward, IMF can be again done (if required)by elastic bands.

• If at the end of surgical procedure, it is desirable to have IMF in situ, then trachea can be extubated through the retromolar route also.

• Oral suction is done through the opposite retromolar space. However, it is mandatory to have cutters to remove IMF for immediate access to airway in case of any emergency.

ADVANTAGES

• Retromolar intubation avoids the need of any surgical airway (tracheostomy and submento- tracheal intubation).

• The retromolar tracheal tube allows adequate dental occlusion, thus rendering intraoperative intermaxillary fixation feasible.

DISADVANTAGE

• In some patients, the retromolar space is not adequate. After retromolar placement of the tracheal tube dental occlusion is not possible. therefore, intraoperative IMF cannot be done.

• This anatomic possibility (of adequate retromolar space) can be determined by introducing the index finger in the patient’s mouth and asking him or her to close the mouth.

• No compression on the finger means fairly adequate retromolar space.

PART 2 FIBREOPTIC RETROMOLAR

INTUBATION

BONLIFS RETROMOLAR INTUBATION FIBROSCOPE

• An awake intubation is considered the primary method to secure a suspected difficult airway.

• Traditionally, an awake intubation is performed by flexible fiberoptic laryngoscopy. However, within the last decade, many new devices have been developed to assist anesthesiologists in managing patients with difficult airways.

• Among these devices are rigid fiberoptic stylets, one of which is the Bonfils Retromolar Intubation Fiberscope

DESCRIPTION

• The Bonfils is a 40 cm long, semi-rigid optical stylet with an external diameter of 5.0 mm and a fixed anterior tip curvature of 40 degrees.

• Its fiberoptic bundle is encased in a stainless steel tube that provides 15,000 pixel resolution.

• The adult stylet can accommodate 6.5 mm endotracheal tubes or larger.

• The pediatric stylet, the Brambrink Intubation Endoscope can accommodate 2.5– 6.0 mm endotracheal tubes

• There are two versions of each stylet. One version has an adjustable eyepiece, allowing for direct visualization during intubation. The other version has a “Direct Coupled Interface” that displays the image directly on a video monitor.

• There is an adaptor “slide cone” for fixation of the endotracheal tube. This adaptor has a side port that allows oxygen insufflation or instillation of local anesthetic

ADVANTAGE

• The narrow shaft of the scope and the 40° angle curve of the distal end minimises the need for significant mouth opening .

• The design also allows for visualisation of more anterior structures. These features make the scope a viable option for difficult and failed intubation scenarios .

• It is effective than direct laryngoscopy where immobilisation of the cervical spine is needed and inter-incisor distance is less

• It requires less leverage on the teeth so the risk of dental injury is less and the risk to ETT cuff damage is reduced as well.

• It does not require excessive manipulation or distraction forces on the cervical spine and has been used successfully in unstable and fixed cervical spine cases.

• The scope has also been used successfully in assisting percutaneous tracheostomy

• The closer and improved view of the glottic allows more precise direction of ETT passage.

• Portable• Used either from the left or right side or

midline.• It can easily push the tumours obscuring the

glottic view.• Small microlaryngeal tubes and double lumen

tubes can also be used.

DISADVANTAGES

• Learning curve.• Cannot be used for nasal intubations• Cannot lift floppy overhanging epiglottis• Blood ,Secretions& fogging limits its visibility.• The rigid body can cause trauma inexperienced hands• non-malleable shaft may limit the ability to angle the scope

in cases where the larynx is extremely anterior.• This may also increase the risk of trapping the ETT against

the patient’s teeth when angling the scope anterior and hence making the railroading of the ETT off the scope difficu.lt

INDICATIONS

CONTRAINDICATIONS

Patient selection

• This includes patient’s history and physical examination,

• reviewing records of previous anaesthetics and airway management,

• Reviewing diagnostic procedures (X-rays, CT scans, MRI scans,nasal scope findings)

• and eliciting specialist opinions.

Superior laryngeal nerve block

• The patient is placed supine with the neck extended. • The hyoid bone is displaced laterally toward the side to be

blocked, and a 25-gauge, 2.5-cm needle is walked off the greater cornu of the hyoid bone inferiorly and advanced 2 to 3 mm.

• As the needle passes through the thyrohyoid membrane, a slight loss of resistance is felt, and 3 mL of local anesthetic solution is injected superficial and deep to this structure.

• The block is then repeated on the opposite side. This technique produces anesthesia from the inferior aspect of the epiglottis to the vocal cords.

TRANSLARYNGEAL NERVE BLOCK

• A translaryngeal block is simple to perform and results in anesthesia of the trachea below the vocal cords.

• With the patient in the supine position, the cricothyroid membrane is located, and a 20-gauge or smaller, 3- to 5-cm plastic catheter over a needle is introduced in the midline.

• The inner steel cannula is withdrawn with the plastic catheter held firmly in place; aspiration of air confirms correct catheter placement.

• Between 3 and 5 mL of a 4% lidocaine solution is injected rapidly and usually results in a vigorous cough, which aids in spread of the solution within the trachea

METHOD TO USE

• patients are placed supine with their head in a neutral position.• The patients are given IV glycopyrrolate 0.2– 0.4 mg, midazolam 1–2 mg, and

incremental doses of fentanyl (50–200 g) or sufentanil (10–20 g) for sedation.• The oropharynx is topically anesthetized with 4 mL of 4% lidocaine spray.• . After sedation, administration of topical lidocaine, and oxygen administration,

the patients are instructed to open their mouths and stick out their tongues.• Although a midline approach is possible, the Bonfils (preloaded with an cuffed

endotracheal tube) is advanced via the retromolar technique to the hypopharynx and advanced towards the posterior pharynx.

• When the Bonfils is positioned immediately in front of the vocal cords, an additional 4 mL of 4% lidocaine was injected onto the cord. After waiting 30–60 s, the Bonfils is advanced further until the tip of the scope just passed the glottic opening. An additional 4 mL of 4% lidocaine is then injected into the trachea

• . After another 30–60 s delay, the endotracheal tube is advanced over the scope. The Bonfils is then removed leaving the endotracheal tube in place.

• End-tidal capnography confirmed tracheal placement followed by routine IV induction

Awake intubation

• Surprisingly awake oral intubations with the Bonfils are not as difficult as one might suspect and in some cases may be easier than the use of the flexible fibreoptic scope.

• After topicalising the airway by routine methods, the left hand is used to hold the patient’s tongue while the right hand inserts the scope on the right.

• A syringe of local anaesthetic should be attached to the working channel of the scope so as to allow delivery of local anaesthetic under direct vision to desired areas.

• A spray of local anaesthetic into the corner of the patient’s mouth followed by inserting the scope superficially into the patient’s pharynx gives a good assessment of his airway.

• In addition, since the distance from the insertion point to the glottis is much shorter using the Bonfils orally as compared to using the flexible fibreoptic scope via the nasal approach, there is less concern about further topicalising the vocal cords and losing sight of the glottis when the patient coughs and trying to re-establish a good view again.

AIRWAY TUMOUR

• The main beneficial use of the Bonfils in these situations is the ability to evaluate the airway under direct vision while minimising the risk of traumatising the tumour causing bleeding, obscuring or obstructing the airway.

• This is due to the fact that there is no leading edge in front of the tip of the camera view that can be blindly inserted into the tumor before seeing and avoiding it.

• When dealingwith airway tumours (especially those in close proximity to the glottic opening), there is a risk of shearing off and catching residual tumour pieces within the hollow aspects of the ETT.

• This potentially can lead to complete obstruction of the distal airway or to a lesser extent seeding of the tumour deeper into the airway

• . The combination of the Bonfils and a snuggly fitted ETT can potentially reduce this risk by eliminating the hollow space within the ETT.

AIRWAY TRAUMA

• It has been speculated that the use of the Bonfils can reduce the risk of sore throats and airway trauma.

• This is because there is less contact to the vallecula and the surrounding structures. There is direct vision as the ETT passes (avoids touching) the vocal cords.

• There are less blind intubations which may lead to inadvertent damage/ subluxation of arytenoids or vocal cords.

• There is also less risk to damaging teeth and implants since there is virtually no leverage on the upper incisors and much less force applied to the stronger molars

References

• The Bonfils Retromolar Intubation Fibrescope: Advantages and Practical Aspects of Its Use By: Theodore Gar-Ling Wong, Bsc ( Med ) , MD , FRCPC ( Canada )

• Awake Insertion of the Bonfils Retromolar Intubation Fiberscope™ in Five Patients with Anticipated Difficult Airways Steven I. Abramson, MD* Allen A. Holmes, MD† Carin A. Hagberg, MD†(Anesth Analg 2008;106:1215–7)

• Technique of Retromolar and Submental Intubation in Facio - Maxillary Trauma Patients Neena Rungta* M.D.,

• RETROMOLAR INTUBATION: A TECHNICAL NOTE Dr. Naveen Malhotra1 Indian J. Anaesth. 2005; 49 (6) : 467 - 468

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