Week 10 - ENT Anesthesia Flashcards
What is the correct positioning of a NIMS tube?
Blue section is between the vocal cords with the black lines facing lateral
What is the functions of the Larynx?
Involved in respiration and speech
Laryngeal reflexes protect the airway
False Cords: ventricular folds (act as muscular valve)
True Cords: act like one way valve, resist pressure from above, but not below)
What nerves innervate the larynx?
Vagus Nerve supplies the larynx:
- Superior Laryngeal Nerve = SENSORY innervation (down to cords)
- Recurrent Laryngeal Nerve = MOTOR innervation to all intrinsic laryngeal muscles except cricothyroid and external branch of superior laryngeal nerve (sensory below true cords as well)
What is the function of the Posterior Cricoarytenoid Muscle?
ABDUCTS the vocal cords
-widen glottic opening during respiration
*Posterior Pulls the cords apart
What is the function of the Thyroarytenoids and Lateral Cricoarytenoids Muscles?
ADDUCTs (relaxes) vocal fold (false cords)
What is the function of the Cricothyroids Muscles?
ADDUCT and TESNE (open) true vocal cords
What is the function of the vocalis muscle?
Shortens true cords
What are considerations with LASER ENT procedures?
– Specific protected tubes w/ dye and saline in balloon
– Warning sign on door
– Protective eyewear for all providers (Eyewear or wet gauze over patients eyes)
– Vacuum/suction for smoke removal
– Special particulate masks
– Low FiO2 < 0.3 - 0.4 - As low as patient will tolerate (Risk of FIRE)
– No N20 - Supports combustion
What are the steps in the case of airway fire?
- STOP delivery of all gases, including O2
- Extubate pt and ventilate with mask, O2 at 100% FiO2
- Maintain anesthesia depth with narcotics, Propofol, muscle relaxants
- Reintubate with smaller tube
- Bronchoscopy/lavage with saline to assess for tracheobronchial damage
What are the anesthetic considerations for Tonsillectomy/Adenoidectomy?
- Aim for smooth emergence to prevent bucking (lidocaine? sufficient opioid)
- Laryngospasm is common
- Suction the stomach (possible blood - PONV)
- Remove throat pack
- Transport in tonsillar position (lateral (semi-prone) with head down)
What is the most common complication and cause of mortality in Tonsillectomy/Adenoidectomy?
Bleeding Tonsil
-seen either immediately, 6-9 hrs post op or 5-10 days later
Symptoms: frequent swallowing, increased HR and respiratory rate, hypotension and pallor
*Consider fluid resuscitation vs blood before GA… awake intubation vs RSI? suction stomach
What are anesthetic considerations for Laryngoscopy/ Esophagoscopy/ Bronch?
- Careful w/ sedation in compromised airways
- Steroids useful after extensive manipulation
- History of smoking and malignancy are common (watch for radiation changes, scarring, abnormal anatomy)
Anesthetic Goals: immobile pt, GA, prompt finish (reflexes return to baseline for extubation)
Ventilation Options: small ETT, adaptation to bronchoscope, jet ventilation
What are the components of Jet ventilation?
100% FiO2
35-75 L/min
At 50 psi
What is used for topical vasoconstriction in ENT procedures?
Cocaine 4% – max dose is 3 mg/kg (1.5 mg/kg preferred), hydrolyzed by pseudocholinesterase, treat toxicity with beta blockers
Epinephrine Solutions – 5 mcg/mL is optimal solution (1:200,000), 200-250 mcg max
- incidence of arrhythmias not related to dose of inhaled agent
- N2O doesn’t enhance epi induced irritability
- increased risk of arrhythmias w/ cocaine, beta agonists, tricyclics, and MAOs
What are the anesthetic considerations for sinus surgery?
- Sinus cavities are closed spaces (N2O diffuses rapidly into closed spaces – best to avoid)
- Ensure full return of airway reflexes
- Suction oropharynx carefully
- Ensure removal of throat pack
- Nose may be packed following surgery (Pt has to breathe through mouth)
- Minimize post op N/V (Scop patch, decadron, zofran, droperidol???)
- Occult bleeding
What is the most common complication with ear procedures?
PONV – be aggressive and communicate with the patient on what to expect
What are the anesthetic considerations for ear procedures?
- Field avoidance
- Facial nerve preservation (No muscle relaxation - Acoustic neuroma surgery)
- Stapedectomy w/ Dr. Ganz (MAC ??? Complicated- Keep pt still)
- Nitrous oxide? – Diffuses into closed spaces very rapidly (middle ear), Passive venting by eustachian tube unless blocked, Space open during tympanoplasty, closed after graft inserted
What are the anesthetic considerations for orthognathic (jaw) procedures?
- Airway/nasal obstruction can be extreme
- Limited jaw motion (airway assessment very difficult/impossible)
- Head Trauma? – neuro evaluation, c-spine precautions/clearance
- Nasal Intubation – use afrin preoperatively (provides better surgical access)
- contraindicated in LeFort II and III
What are the anesthetic considerations for radical neck dissection/free flap?
- Pt usually has hx of smoking/COPD
- Lengthy procedures – skin grafting and muscular free flap placement vs rotational flap
- Not recommended to avoid pressors anymore (Dopamine preferred but do what you need to to keep BP up)
- Airway manipulation may be impossible (distortion of anatomy – awake tracheostomy by surgeon under MAC may be necessary)
What are intraop considerations for neck dissection procedures?
- Field avoidance – rectal temp probe place
- Nerve preservation??
- Blood loss usually well controlled
- Monitor volume status (foley)
What are complications of neck dissection procedures?
Vagal Reflexes: surgical manipulation of carotid sinus – manipulation of stellate ganglion
- BP swings, bradycardia, dysrhythmias, sinus arrest, prolonged QT interval
- treat with IV atropine, surgeon can infiltrate w/ lidocaine
Venous Air Embolus: head elevated, large open veins in neck, have surgeon flood field, support hemodynamically
What are post op complications of thyroid and parathyroid surgery?
Airway compressing hematoma
Hypocalcemia (usually a 24 hr admit to assess Ca)
Recurrent laryngeal nerve injury
*stridor postop may be due to hypocalcemia or recurrent laryngeal nerve injury so important to figure out what is the cause
What are the two types of recurrent laryngeal nerve injury?
Unilateral: causes cord on injured side to assume midline position = hoarseness
Bilateral: causes both cords to close to midline (adducted) position = aphonia and airway obstruction occurs (airway emergency!!)
*can occur with intubation, neck surgery, or stretching of neck, thyroid or cervical spine surgery
If airway obstruction occurs after thyroid surgery, what could be the cause?
Hypocalcemia or Bilateral Recurrent Laryngeal Nerve Injury
What nerve mediates a laryngospasm?
Superior laryngeal Nerve
-reflex closure of upper airway from spasm of glottic muscles
What is the treatment for laryngospasm?
- IV lidocaine (1-2 mg/kg) 30-45 min prior to emergence
- Sustained positive pressure along with increasing depth of anesthesia (IV propofol, volatile, succinylcholine 10-50mg IV)
- Pressure to the postcondylar notch (really hard pressure)
What is the treatment of Stridor?
- O2 via facemask and head in midline position with HOB up at 45-90 degrees
- Nebulized racemic epi
- Heliox (70% helium 30% O2) – decreases in airway resistance and improves ventilation
What are the effects of anesthetic agents on IOP?
inhaled anesthetics = decrease
IV anesthetics = decrease
Muscle relaxants = non-depolarizers decrease and SUX increases
What is the nerve impulse pathway for the oculocardiac reflex?
Ophthalmic division of trigeminal nerve (CN V) carries impulse to
the brain via grasserian ganglion –> continues to the sensory nucleus of CN V in brainstem –> fibers in reticular formation synapse w/ nucleus of vagus nerve –> efferent fibers from vagus terminate in the heart
*causes bradycardia, nodal rhythm, V-fib, and even cardiac arrest
How do you treat oculocardiac reflex?
- Removal of surgical stimulus until HR increases
- Confirmation of adequate ventilation/oxygenation/depth of anesthesia
- IV atropine 0.01-0.02 mg/kg
- If repeatedly happens have surgeon inject rectus muscles w/ local anesthetic
What is the most common cause of postop eye pain after GETA?
Corneal Abrasion
- manifests w/ conjunctivitis, tearing, and foreign body sensation
- can occur mechanically via scratching from ID tags, mask, drapes, inappropriate taping, pt rubbing eyes
Preventative measures: gently taping, ointments are not often used, protective goggles
