vent modes Flashcards
describe assist control
triggered by the pt’s inspiratory effort, then delivers a set TV
back-up rate to avoid hypoventilation, can provide PEEP in backup mode
describe pressure support
clinician sets:
* inspiratory time
* Ppeak to be delivered
* the trigger
popular in ICUs when wearing pts from the ventilator and requires apnea alarm and backup mode in OR
describe IMV (intermittent mandatory ventilation)
clinician sets:
* MANDATORY pressure or volume
* RR
* inspiratory time
pt is guaranteed the mandatory breaths set but pt can still produce spontaneous breaths (which can receive assistance from the ventilator)
what is the main problem with IMV?
breath stacking!
b/c mandatory breaths can occur on top of pt’s spontaneous breath = BAROTRAUMA!
describe SIMV (synchronized int mandatory ventilation)
clinician sets:
* MANDATORY pressure or volume
* RR
* inspiratory time
(just like IMV, except will synchronize the spontaneous breaths instead of allowing stacking)
created to AVOID breath stacking seen with IMV! synchronizes the extra breath with the set rate!
what is the biggest difference between assisted vent support vs controlled breathing modes?
pt CANNOT contribute an effort to the respiratory cycle - used when pt gets NMBDs
describe pressure control
- pressure is FIXED (set RR, Ppeak, and I:E ratio)
- volume is variable - so set an alarm for decreased TV indicating poor compliance!
what kind of patients might get placed on presssure control?
LMA cases, pts we want to keep airway pressures low, COPD/asthma
describe volume control
- volume is FIXED (set TV, RR, and I:E ratio)
- pressure is variable - be careful with this settings in pts with potentially elevated peak pressures b/c barotrauma!!
describe volume guarantee pressure control
allows the vent to deliver constant volumes even if there’s large changes in pressure (ex: robotic hysterectomy)
watch the Ppeak alarm in this setting!
in what cases would you want to use Volume Guarantee Pressure Control?
high intra-abdominal pressure surgical procedures (ex: robotic hysterectomy), morbidly obese, pregnancy
what vent mode is spontaneous breathing without assistance?
CPAP - set pressure that is continuous w/ inhalation and exhalation
* normal settings: 5-20 cmH2O
* helps recruit alveoli and facilitate oxygenation
* does increase intrathoracic pressure and may create air-trapping in COPD patients
