September 10, 2012 by EmerJencyWEBB
THIS great narrative from Emergency Medicine News lead to a morning reading from the literature about intubation, mechanical ventilation, and complications associated with the severe asthmatic. I found two great papers on the topic with links below.
What follows are some pearls gathered from the above texts.
- glycopyrolate, atropine, lidocaine, albuterol have all been studied to blunt bronchospasm initiated by intubation.
- lidocaine dose 1.5mg/kg, 3 minutes before intubation.
- THIS STUDY showed superiority of 4 puffs albuterol to IV lidocaine for pre-treatment
OTHER PRE-INTUBATION THOUGHTS
- IVF bolus
- Pick out the largest bore endotracheal tube you think will go in. The key is to reduce airway resistance.
- Method of choice is RSI
- Induction Agents: Consider Ketamine (1.5-2mg/kg IBW IV, hypotensive/normotensive patient) or Propofol (hypertensive patient, 2mg/kg IV over 2 minutes) as both have bronchodilatory effect.
- Paralytics: Succinylcholine or Rocuronium (theoretical histamine release associated with sux has not been proven to be detrimental in clinical setting, however if the patient is hyperkalemic prior to intubation, use caution)
- Set up post-intubation therapy/mechanical ventilation strategy to reduce hyperinflation, as these patients are prone to develop
- If you have to choose, pick hypercapnia over hyperinflation
Know initial ventilator settings:
Recognize air-trapping on the ventilator waveform:
Know how to estimate lung hyperinflation using the vent:
In common practice 2 relatively easy-to-measure pressures are used as surrogate markers of lung inflation: auto-PEEP and plateau pressure (Pplat). Auto-PEEP is an estimate of the lowest average alveolar pressure achieved during the respira- tory cycle. It is obtained by measuring airway-opening pressure during an end-expiratory hold maneuver. The presence of expiratory gas flow at the beginning of inspiration (which can be detected by means of auscultation or flow tracings) also suggests auto-PEEP. Auto-PEEP can underestimate the sever- ity of hyperinflation when there is poor communication between the alveoli and the airway opening (35).
Pplat (or lung distension pressure) estimates average end- inspiratory alveolar pressure. Pplat is affected by the entire respiratory system, including lung parenchyma, the chest wall, and the abdomen. It is determined by temporarily stopping flow at end-inspiration during a single delivered breath.
Initiate Sedation/Short Term Paralysis
- Key for patient-ventilator synchrony
- Consider benzodiazepine/fentanyl combination
- Propofol may also be useful, but know complications of extended use
- Long term paralysis (>24 hrs) not recommended, due to myopathy, decreased weaning from vent.
Be ready for post-intubation complications:
Another great algorithm, putting it all together: