difficult airways
DESCRIPTION
Difficult Airways. Presented by Ri 龔律至 Ri 李又文. Brief history. 59 y/o male Oropharyngeal ca.(SCC) s/p CCRT in 2000 Local recurrent oropharyngeal ca. s/p Nd-YAG laser tonsillectomy in 2001 Denied any other systemic disease Alcohol, betelnut, or cigarette consumption: denied. - PowerPoint PPT PresentationTRANSCRIPT
Difficult Airways
Presented by Ri 龔律至 Ri 李又文
Brief history 59 y/o male Oropharyngeal ca.(SCC) s/p CCRT in 2000 Local recurrent oropharyngeal ca. s/p Nd-Y
AG laser tonsillectomy in 2001 Denied any other systemic disease Alcohol, betelnut, or cigarette consumption:
denied
Present Illness Dysphagia was noted since 2002 Sep. PES with biopsy showed middle and lower
esophageal squamous cell carcinoma. CCRT (4000cGy / 20 Fractions) was perfor
med and he was referred for subtotal esophagectomy.
Pre-op evaluation ASA class II Previous intubation hx: No difficult airway w
as noted. Mouth opening < 2 cm
Awake Fiberoptic Intubation RobinulFentanyl lidocaine +Neo-Synesi
n for nasopharynx topical use transtracheal injection of lidocaine successful ETT intubation Pentothal Tracrium
Post op evaluation Sore throat : (-) Vomiting, headache : (-) Pain control : Epidural Pain score : 4 / 10 The patient was satisfied with the quality of
the anesthetic process.
Difficult Airways
Difficult airway is defined when trained anesthesiologist experiences difficulty with mask ventilation (unable to maintain SpO2>90% using 100% O2) and/or inability to place ETT with conventional laryngoscopy (>3 attempts or > 10 mins)
Difficult Airways Include both difficult intubations and
compromised airways. Compromised airways implies partial
obstruction to air flow and the risk of total obstruction if tumor, infection, or disease further narrows the airway.
All compromised airways are difficult intubations!
Difficult Intubation During routine anesthesia the incidence of
difficult tracheal intubation has been estimated 3~18%.
Difficult IntubationThe best view of the larynx seen at laryngoscopy
Cormack classification Class I: the vocal cords are visible
Class II: the vocals cords are only
partly visibleClass III: only the epiglottis is
seenClass IV: the epiglottis cannot be
seen
Predicting Difficult Intubation
History A.Previous intubation history B.Facial/maxillary trauma C.Small mandibles or intra-oral pathology such as infections or tumors D.Rheumatoid disease of the neck or degenerative spinal diseases E.Spinal cord injury F.Poor teeth and the inability to open the mouth
Specific Screening Tests to Predict Difficult Intubation
View obtained during Mallampati test:1.Faucial pillars, soft palate
and uvula visualised 2.Faucial pillars and soft palate visualised, but uvula masked by the base of the tongue 3.Only soft palate visualised 4.Soft palate not seen.
Specific Screening Tests to Predict Difficult Intubation
1. Thyromental distance
2. Sternomental distance
3. Protrusion of the mandible
4. Mouth opening
5. Ability to flex and extend the neck maximally
6. X-ray studies
7. Preoperative assessment
Thyromental distance Frerk showed that patient
s who fulfilled the criteria of Gr 3 or 4 Mallampati who also had a thyromental distance of less 7 cm were likely to present difficulty with intubation
Sternomental distance Measured from the sternum to the tip of the
mandible with the head extended and is influenced by a number of factors including neck extension.
A Sternomental distance of 12.5 cm or less predicted difficult intubation.
Mouth Opening Mouth opening, which is largely a function o
f the temporomandibular, is a prime importance to allow the insertion of a blade and subsequent glottic visualization.
Adults should be able to open their mouth >3~4 cm (between upper and lower incisors).
Protrusion of the mandible An indication of the mobility of the mandible.
If the patient is able to protrude the lower te
eth beyond the upper incisors, intubation is usually straightforward
Limitation Wilson et al studied a combination of these
factors in a surgical population assigning scores. Although their method can predict many difficult intubations, it also produces a high incidence of false positives (someone who is assessed as a likely difficult intubation, but who proves easy to intubate when anesthetised) which limits its usefulness.
Special techniques for intubation: Awake Intubation
=Conscious intubation After appropriate sedation, topical anethesia, an
d nerve blocks, such intubations can be performed with minimal discomfort in the conscious patient.
Nasal intubation is the best method of awake intubation using a fiberoptic bronchoscope.
Awake Intubation
Sedation: fentanyl is recommended. Anticholinergic agent, such as Robinul is st
rongly advised. Anethesia of the nares and nasopharynx sh
ould be accompanied by vasoconstriction to widen the passage and decrease bleeding.
Awake Intubation Nasopharygeal anesthesia:
(1) Cocaine (4%) up to 1.5 mg/kg
(2) Lidocaine (4%) + Neo-Synesin (1%) in a
3:1 combination Transtracheal (translaryngeal) anesthesia wit
h 2~3 ml 2% lidocaine injection. Glossopharyngeal block
Special techniques for intubation
The Laryngeal Mask Airway The McCoy laryngoscope Light wand The Combi-tube Retrograde endotracheal intubation Surgical airway
The Laryngeal Mask Airway
The McCoy laryngoscope
The McCoy laryngoscope is designed with a movable tip which allows the epiglottis to be lifted and intubation often made easier.
The Combi-tube The Combi-tube is a tu
be which may be inserted blindly and used to ventilate the patient in an emergency. It is designed in such a way that the tube can be used for ventilation whether it enters the esophagus or the trachea.
Retrograde endotracheal intubation
Transtracheal Jet Ventilation(TTJV)
Benumof noted that the incidence of “ cannot ventilate-cannot intubate” situation may be as high as 1/ 5000 anesthesics.
TTJV is a quick, easy, safe solution to the problem of “ cannot ventilate-cannot intubate”.