1. Which of the following is NOT an indication for endotracheal intubation?
a) Pediatric trauma patient presenting with a GCS of 7
b) Guillain Barre patient with a NIF of 15 cm H2O
c) 2 month old infant with botulism
d) Continued shock due to LV dysfunction despite epinephrine and milrinone infusions
2. How does preoxygenation before intubation work?
a) Increases PaO2, thereby allowing a reservoir of oxygen to diffuse into tissues
b) Replaces nitrogen in the functional residual capacity, thereby providing a reservoir of oxygen
c) Replaces carbon dioxide in the lungs, thereby providing a reservoir of oxygen
d) Improves the SpO2, thereby providing a reservoir of oxygen while apneic
3. Which of the following pairs of medication/adverse effect is INCORRECTLY paired?
a) Ketamine-emergence delerium
b) Lidocaine- increased ICP
c) Fentanyl- Rigid chest syndrome
d) Etomidate-11 B hydroxylase inhibition
ANSWERS & EXPLANATIONS
1. C- while the 2 month old patient with botulism may eventually require endotracheal intubation, botulism in and of itself is not an indication for endotracheal intubation unless there are signs of impending respiratory failure or significant respiratory distress. A GCS <8 in a trauma patient would suggest an inability to protect one's airway and is generally considered an indication for intubation. A NIF of <20 cmH2O is suggestive of significant diaphragmatic impairment and impending respiratory failure in patients with Guillain Barre syndrome, and hence, an indication for intubation. Refractory shock, particularly with LV dysfunction, would also be an indication for intubation as it would not only decrease LV afterload, but also decrease metabolic demand by reducing work of breathing (and potentially allowing for neuromuscular blockade and sedation which might also decrease metabolic demand).
2. B- preoxygenation functions to denitrogenate the functional residual capacity (takes up 79% of the alveolus normally), creating a reservoir of oxygen to diffuse into the blood even after the patient has been apneic. Due to smaller FRC's and relatively higher basal metabolic rates in young children, the time to desaturation is much shorter in pediatric patients than in adults (ie healthy adult may not desaturate for 5-9 minutes) but still provides a reasonable buffer in case of difficulty with accessing the airway.
3. B- Lidocaine is used to premedicate against ICP spikes with laryngoscopy and does NOT cause increased ICP. Each of the other pairs are correctly matched with potential significant adverse effects.