There’s so much to be learned in the ICU on a day to day basis that I feel like I don’t do a good enough job solidifying what I learn in my brain. I’ve learned a lot each day about both the process of doctoring and the medicine itself. Since I feel like I’ve been kinda getting repetitive or at least somewhat stale in this posts, I feel like I will try to use this space to help nail down the things I am learning while still having space to put my reflections.
Today we talked about a few things. Pressure-volume loops in individuals with different types of airway obstructions. First there are fixed airway obstructions in which the loop is flattened in both the inspiratory and expiratory phases. Which makes sense; if you have a small opening for air to go in and out and it doesn’t change, the flow will be inhibited in both directions. Then there are variable intrathoracic obstructions and variable extrathoracic obstructions. The terminology was confusing to me at first, I think because I didn’t quite understand that we where talking specifically about airway obstructions and not just any kind of inhibition of flow. Thinking about it now, this actually will help a lot in me thinking about airway obstructions vs restrictions. Anyway, for variable intrathoracic obstructions, there is negative pressure in the intrathoracic space during inhalation so when the person inhales, the soft tissues is able to move out of the airway to allow air to flow unobstructed. During exhalation when that negative intrathoracic pressure is gone, the obstruction is then present, inhibiting flow on exhalation, therefore only the exhalation phases is flattened. On the other hand for a variable extrathoracic obstruction, during inhalation the negative pressure is in the airway lumen causing the obstruction to worsen, and then during exhalation when that negative pressure is gone, the airway can open up again and you get the opposite effect on the pressure-volume loop. From a Med+Peds perspective, this also helps me better understand possible clinical findings related to airway obstruction such as stridor and wheezing (just because these are probably more common findings in the younger hospitalized population), and know when we would expect to hear those abnormal breath sounds. That’s all for now.
nANIMOv 