We treat asthma on a daily basis, especially in the peds ED. But what if duonebs x3, steroids, and mag isn’t doing the trick?
THE CRASHING ASTHMATIC
Nebulized epinephrine may help.
If no improvement, start dosing IM epi as if it were anaphylaxis: 0.5 mg (0.01 mg/kg) q 10 min, or start a drip at 5 mcg/min and titrate to effect.
Keep going with continuous albuterol nebs.
If pharmacy isn’t around to make an epi drip, consider a “dirty” epi drip: 1 mg epi (an entire vial of code cart epi) added to 1 L NS or LR, start at 2 drops per second and titrate up.
Alternatively, terbutaline IV can be started: 10 mcg/kg bolus over 10 min and then drip starting at 0.4 mcg/kg/min and titrate up. Terbutaline is a systemic beta agonist. Perhaps they’re so tight that the albuterol you’re nebulizing is not getting where it needs to go due to profound bronchoconstriction. The main adverse effect is here is vasodilation-related hypotension.
By this point, your intubation stuff should be ready and the patient should be in resus.
They also will be having insensible losses so should get as 20 cc/kg IVF bolus.
Still getting worse.
Now this gets interesting.
We are really trying to avoid intubating any asthmatic because of historically poor outcomes with intubation, but sometimes it is unavoidable.
Next step is to try BiPAP. BiPAP could also be started simultaneously with epi. If they can’t tolerate BiPAP, consider ketamine to help them tolerate BiPAP. Ketamine can be dosed numerous ways. If sub-dissociative dosing is pursued, you risk them freaking out. If dissociative dosing, there’s a higher risk of laryngospasm. But consider this, they’re on the brink of getting intubated anyway. If your last-ditch-effort-ketamine gives them laryngospasm, that might be your cue to push a paralytic.
Ketamine and BiPAP has failed.
Time to intubate. Preoxygenate as much as possible. Use the largest ETT possible. First pass success is key. Induce with ketamine 2 mg/kg if they’re not already in the K-Hole. Roc or Sux.
Now they’re intubated
They have OBSTRUCTIVE LUNG PHYSIOLOGY. It will take them way longer than usual to exhale. Thus:
Low respiratory rate! 8 breaths/min
Lung protective tidal volume: 7 cc/kg ideal body weight
Minimal PEEP: 0 (ZEEP) - 2 cc H2O
High inspiratory flow rate: 90 LPM or I:E 1:5
FiO2 100%
The ventilator will alarm due to high PEAK pressures. This is OK. Have the respiratory therapist fix it to raise the alarm threshold. The high peak pressures are a consequence of their tight bronchioles.
If running into issues with ventilator dyssynchrony, consider paralyzing with cisatracuium
Relative hypoxia (sat mid 80s, goal >90%) and hypercarbia (goal >7.15) is OK
Aggressive airway suctioning
If they begin crashing, disconnect from vent and push on chest to ensure breath stacking is not the issue; rule out pneumothorax; rule out displaced/clogged/kinked ETT
Still doing poorly
Call the ECMO team for VV ECMO
Anesthesia to set up inhaled anesthetics! e.g. desflurane, sevoflurane. Not tons of evidence, but in case series' and anecdotally, this works really well.
Fun fact, CO2 can be dialyzed out of someone rather than ventilated out of someone. However, you need to be in a center where ECMO is also done, because it’s basically putting a piece of the ECMO circuit into a CVVHD circuit. Yes. Blew my mind too.
See Reuben’s algorithm on this at https://emupdates.com/when-the-patient-cant-breathe-and-you-cant-think-the-emergency-departement-life-threatening-asthma-flowsheet/