Category: Critical Care
Keywords: mechanical ventilation, respiratory failure, obstructive lung disease, asthma exacerbation, COPD (PubMed Search)
Managing the intubated patient with exacerbation of severe obstructive lung disease, especially asthma, can be very challenging as it carries higher risks of barotrauma due to higher pulmonary pressures and circulatory collapse due to auto-PEEP and decreased venous return. When measures such as medical therapy and noninvasive positive-pressure ventilation fail to prevent intubation, here are some tips to help:
1. Utilize a volume control ventilation mode to ensure a set tidal volume delivery / minute ventilation, as pressure-targeted modes will be more difficult due to the high pulmonary pressures in acute obstructive lung disease.
2. Set a low RR in order to allow for full exhalation, avoiding air-trapping / breath-stacking and circulatory collapse due to decreased venous return. This may require deep sedation and potentially paralysis.
3. Increase your inspiratory flow by shortening your inspiratory time (thereby increasing your time for exhalation.
4. Monitor for auto-PEEP:
5. Peak inspiratory pressures will be high -- what is more important is the plateau pressure, measured by performing an inspiratory hold at the end of inspiration. Provided your plateau pressure remains <30, you don't need to worry as much about the peak pressure alarms.
6. If your patient acutely decompensates in terms of hemodynamics and oxygenation -- first attempt to decompress their likely auto-PEEPed lungs by popping them off the ventilator and manually press on their chest to assist with exhalation of stacked breaths allowing venous return to the heart.