Vent Comp Flashcards
what is the standard criteria for instituting mechanical ventilation
- apnea or absence of breathing
- acute ventilatory failure
- impending ventilatory failure
- refractory hypoxemia with increase work of breathing
what are possible complications associated with mechanical ventilation
- self-extubation
- mechanical failure
- atelectasis
- pneumonia
- massive gastric distension
- hypotension
identify the following as either mandatory breath, spontaneous breath, or assisted breath:
flow triggered, pressure targeted, time cycled
assisted
identify the following as either mandatory breath, spontaneous breath, or assisted breath:
time triggered, volume targeted, volume cycled
assist
identify the following as either mandatory breath, spontaneous breath, or assisted breath:
pressure triggered, pressure targeted, time cycled
mandatory
identify the following as either mandatory breath, spontaneous breath, or assisted breath:
flow triggered, pressure targeted, flow cycled
spontaneous
if a patients ventilatory drive increases during the use of VC-CMV, what change will occur to the patients acid base balance
the patients assist rate will increase
Since every breath will be a machine breath at the set volume, this can easily lead to a decreased PaCO2 or respiratory alkalosis.
what can be done to fix the acid base problem of a patient whos ventilatory drive has increased on VC-CMV
identification of the source of the increased drive (i.e., fever, sepsis, etc.) and correction of this are the best ways to control the respiratory alkalosis
However, since this may take some time, sedatives, paralytic agents, or switching to SIMV with similar settings may be tried
a patient is being mechanically ventilated with 50% FiO2. His PaO2 is 60 mmHg. The physician orders are to titrate FiO2 to maintain PaO2 90 mmHg. Recommend the most appropriate FiO2 to use at this time
Desired FiO2 = (desired PaO2 + know FiO2) / know PaO2
(90 + 0.5) / 60 = 1.5
1.5 x 50 = 75
Desired FiO2 = 75%
list 2 diagnostic procedures the RT should recommend after placing a patient on mechanical ventilation
121? CBC ABG Blood Chem PT/PTT/INR Blood, urine, sputum culture
how is a trigger set
machine dettects variable when to begin breath
how is a limit set
machine measures limit variable not allowing maximum to be exceeded
how is a cycle set
machine measures cycle variable to govern when ventilator will end gas flow
what type triggers are there
time: when set time has elapsed to give breath
patient: when patient effort is detected to give breath
flow: when drop in flow is detected to give breath
what type limits are there
pressure: rise to certain value without exceeding it
volume: set volume value without exceeding it
flow: set flow value without exceeding it
what type cycles are there
volume: when set volume is delivered
time: when predetermined time has elapsed
flow: when flow decreases to predetermined value
pressure: when set pressure threshold is reached
what is compliance
the relative ease with which the structure distends the opposite or inverse of elastance
what is airway resistance (Raw)
frictional forces that must be overcome during breathing
what is the formula for static compliance
CS = VT / (Pplat - PEEP)
what is the formula for dynamic compliance
CD = VT / (PIP -PEEP)
what is the formula for airway resistance
Raw = (PIP-Pplat) / inspiratory flow
how does static compliance affect the breath delivery and mode PC-CMV
pressure remains constant
delivered Vt decreases
pressure must increase when compliance decreases to maintain adequate Vt
how does dynamic compliance affect the breath delivery and mode VC-CMV
volume delivery constant
high pressures
regardless of change in CD
how do you recognize changes in compliance on the ventilator
