Laryngospasm Flashcards
What is laryngospasm?
The sustained and involuntary contraction of the vocal cord adductors that results in the inability to ventilate.
What are potential consequences of laryngospasm?
- Complete airway obstruction
- Negative pressure pulmonary edema
- Gastric aspiration
- Cardiac arrest
- Death
What age group is at higher risk for laryngospasm?
Age < 1 year
Does hypocapnia or hypercapnia increase the risk of laryngospasm?
Hypocapnia
Does light anesthesia or deep anesthesia increase the risk of laryngospasm?
Light anesthesia
Name a risk factor for laryngospasm related to upper airway conditions.
Saliva or blood in the upper airway
What gastrointestinal condition is a risk factor for laryngospasm?
Gastroesophageal reflux disease
True or False: Exposure to secondhand smoke is a risk factor for laryngospasm.
True
What recent illness can increase the risk of laryngospasm?
Recent upper respiratory tract infection
What is laryngospasm?
Laryngospasm is the sustained and involuntary contraction of the laryngeal musculature that results in the inability to ventilate. This response often outlasts the stimulus.
What are the complications of laryngospasm?
Complications include airway obstruction, negative pressure pulmonary edema, pulmonary aspiration of gastric contents, cardiac dysrhythmias, cardiac arrest, and death.
What is the afferent limb of the gag reflex pathway?
The afferent limb is the glossopharyngeal nerve (IX
0
What is the efferent limb of the gag reflex pathway?
The efferent limb is the vagus nerve (X)
What is the role of the cricothyroid muscle in laryngospasm?
The cricothyroid muscle elongates (tenses) the vocal cords.
What is the role of the lateral cricoarytenoid muscle in laryngospasm?
The lateral cricoarytenoid muscle ADDucts the vocal cords (closes glottis).
What is the role of the thyroarytenoid muscle in laryngospasm?
The thyroarytenoid muscle ADDucts the vocal cords (closes glottis) and relaxes (shortens)
Signs of Laryngospasm:
Inspiratory stridor, Suprasternal and supraclavicular retraction during inspiration, “Rocking horse” appearance of the chest wall (paradoxical movement), Increased diaphragmatic excursion, Lower rib flailing, Absent or altered EtCO, waveform
Risk Factors of Preanesthetic
- Active/recent resp infection (<2 weeks)
- Exposure to 2nd hand smoke
- GERD
- Age <1 yr
What are pre-anesthetic risk factors in the operating room?
Light anesthesia (especially with concurrent airway manipulation - such as suctioning the patient or placing an oral airway)
What can be a risk factor related to airway obstruction?
Saliva or blood in the upper airway
What respiratory condition is a risk factor during anesthesia?
Hyperventilation / hypocapnia
What types of surgical procedures in the airway are risk factors?
Tonsillectomy, Adenoidectomy, Nasal / sinus, Laryngoscopy, Bronchoscopy, Palatal
What should be avoided during light anesthesia to reduce the risk of laryngospasm?
Avoidance of airway manipulation during light anesthesia
What CPAP level should be used during inhalation induction and immediately after extubation?
CPAP 5 - 10 cm/H20 during inhalation induction as well as immediately after extubation
What should be removed before extubation to reduce the risk of laryngospasm?
Remove pharyngeal secretions and blood before extubation
When should tracheal extubation occur?
Tracheal extubation when deeply anesthetized or fully awake — not in-between!
What is the duration of laryngeal lidocaine?
Laryngeal lidocaine (duration lasts ~ 30 min)
What should be administered IV before extubation?
IV lidocaine before extubation
What is the first intervention for treating laryngospasm?
FiO2 100% and suction if needed
What is the second intervention for treating laryngospasm?
Remove stimuli and deepen anesthesia
What is the third intervention for treating laryngospasm?
Larson’s maneuver and CPAP 15 - 20 cm H2O while opening the airway (head extension, chin lift, Larson’s maneuver).
How can you deepen anesthesia during laryngospasm treatment?
By increasing the concentration of volatile agent or with a small dose of propofol or lidocaine.
If the patient has complete laryngospasm, increasing the volatile agent may not be efficacious.
What is the recommended IV dosing of succinylcholine for neonates or infants?
IV: 2 mg/kg.
What is the recommended IV dosing of succinylcholine for adults or children?
1 mg/kg.
You may see a range of 0.1 - 1.0 mg/kg in the texts (a dose of 0.1 mg/kg tends to preserve ventilation).
What is the recommended IM dosing of succinylcholine for neonates or infants?
5 mg/kg.
What is the recommended IM dosing of succinylcholine for adults or children?
4 mg/kg.
What administration method may produce the fastest onset of succinylcholine?
Submental administration.
What should you do if the patient does not have IV access and succinylcholine is contraindicated?
Rocuronium is the only other NMB that can be given IM.
What should be co-administered with succinylcholine to children < 5 years?
Atropine 0.02 mg/kg to prevent bradycardia.
What is Larson’s maneuver?
Larson’s maneuver is the application of firm pressure to the laryngospasm notch located just behind the earlobe. Making the patient sigh
How is pressure applied in Larson’s maneuver?
Pressure is applied bilaterally towards the skull base.
What are the two goals of Larson’s maneuver?
- Displaces the mandible anteriorly to help open the airway.
- Breaks laryngospasm by causing a lightly anesthetized patient to sigh.
What are the borders of the laryngospasm notch?
Superior = Skull base, Anterior = Ramus of mandible, Posterior = Mastoid process.
How long should pressure be applied during Larson’s maneuver?
Pressure should be applied for 3 - 5 seconds then released for 5 - 10 seconds.
How often should Larson’s maneuver be repeated?
Repeat until the laryngospasm breaks.
What is Valsalva’s maneuver?
Exhalation against a closed glottis (or obstruction).
Example = Coughing, bucking, or bearing down.
What are the risks associated with Valsalva’s maneuver?
Increased pressure in the thorax, abdomen, and brain.
What is Muller’s maneuver?
Inhalation against a closed glottis (or obstruction).
Example = Patient bites down on ETT and takes a deep breath.
What is the risk associated with Muller’s maneuver?
Subatmospheric pressure in the thorax → negative pressure pulmonary edema.
Where does the lower airway begin and end?
The lower airway begins at the trachea and ends at the alveoli.
Where does the trachea start and end?
The trachea begins at the inferior border of the cricoid cartilage (level C6) and ends at the carina (T4-5).
How does neck flexion affect the distance from the mouth to the carina?
Neck flexion reduces the distance from the mouth to the carina.
How does neck extension affect the distance from the mouth to the carina?
Neck extension increases this distance (the tube goes where the nose goes).
What is the length of the left bronchus?
The left bronchus is 5 cm in length.
At what angle does the left bronchus take off from the trachea?
The left bronchus takes off at 45 degrees from the long axis of the trachea.
What is the length of the right bronchus?
The right bronchus is 2.5 cm in length.
At what angle does the right bronchus take off from the trachea?
The right bronchus projects about 25 degrees.
Why is there a greater likelihood for right mainstem intubation?
The anatomical differences in bronchus length and angle explain the greater likelihood for right mainstem intubation.
What is the angle of bronchial takeoff in children up to 3 years of age?
Both bronchi take off 55 degrees from the long axis of the trachea in children up to 3 years of age.
How many generations does the lower airway bifurcate?
The lower airway continues to bifurcate along 23 generations.
What is the function of type 1 pneumocytes?
Type 1 pneumocytes provide the surface for gas exchange.
What do type 2 pneumocytes produce?
Type 2 pneumocytes produce surfactant.
Can type 2 pneumocytes produce type 1 pneumocytes?
Yes, type 2 pneumocytes can also produce type 1 pneumocytes.
What does the Mallampati exam assess?
The Mallampati exam assesses the oropharyngeal space.
What is the relationship between the Mallampati score and intubation difficulty?
A higher Mallampati score (3 or 4) is associated with a more difficult intubation.
Is the Mallampati exam a good predictor of a difficult airway?
By itself, Mallampati is a poor predictor of a difficult airway. Using it in combination with other airway exams increases its predictive power.
What does the inter-incisor gap assess?
The inter-incisor gap assesses how well the patient can open his mouth, which directly affects the alignment of the oral, pharyngeal, and laryngeal axes.
How does a small inter-incisor gap affect intubation?
A small inter-incisor gap creates a more acute angle between the oral and glottic openings, increasing the difficulty of intubation.
What is the normal range for the inter-incisor gap?
Normal = 2-3 finger breadths (4 cm)
What factors can affect the inter-incisor gap?
Long incisors reduce the gap and buck teeth increase the risk of dental damage.
