ICU Vent question

[GuineaPigs, BSN, RN]

I'm new to ICU and trying to learn ventilators and I'd like to clarify PS/PC above PEEP.

I understand that PEEP (Positive end expiratory pressure) is the pressure remaining in the airways (primarily alveoli) to keep it recruited. PS (pressure support) & PC (pressure control) both deliver extra 'pressure' for the patient, but PC has a backup rate to prevent apnea (done so by either a patient or time trigger). Whereas PS only provides some pressure to make the work of breathing a little easier for the patient by adding some extra 'pressure' w/their own breath. However there's no backup rate for PS and so it's often used as a weaning mode.

I understand that Ppeak (dynamic pressure) is a measurement of flow/movement pressure in the upper airway and the Pplateau (static pressure) is the pressure in the lower airways. I know that by adding the PEEP and PS/PC above PEEP results in the total Ppeak. What does the 'PS/PC above PEEP' mean? Does it mean that the vent will add however much pressure is needed above the base PEEP level until it reaches the Ppeak? So if the PEEP is set at 5, and PS/PC above PEEP is 10. Then it means that for that particular patient, they are okay with a pressure level in the airways up to 15?

[LovingLife123]

We don’t use pressure control as we use volume control. But from what I am reading they are very close. Volume control is where the ventilator is doing the work. The pressure control has a variable tidal volume rate where volume control has a set volume rate. But the ventilator is doing the work.

With pressure support there is a minimum rate and peep. The patient breathes on their own with a minimum peep support. But they set the respiratory rate and tidal volumes. The ventilator kicks in when they fall below the minimum settings.

An apnea mode is usually used in the full spontaneous breathing trial mode. Sometimes though it can alarm apnea when the patient is actually just taking long, deep breaths.

[Pheebz777, BSN, RN]

Peak pressure is basically pressure in the airway circuit. Increased secretions, fluid filled bronchioli, patient biting the ETT for example will directly affect peak pressure. Now once you've taken away all variables affecting peak pressure, what you have left is Plateau pressure which is essentially lung compliance or the ability of the lungs to expand and relax in response to respiration.

And yes you are right that whatever is the PEEP, you add that to the pressure support. In your above example, PEEP 5 + 10 of PS = 15