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
review modes:
what are they
what type breath is delivered/given
when are they used
what things can be added to modes
what is the purpose of setting PEEP
used to prevent alveolar collapse and recruit alveoli
what is the purpose of setting PS
what is the purpose of setting I-time
normally patient will have low lung compliance and normal Raw so I time must be short
what is the purpose of setting flow
rapid inspiratory flows increase PIP, but higher inspiratory flows allow for Vt delivery in short time which produces lower Paw
three points to note when using high flow:
- more pressure will lost to patient circuit with high PIP
- more pressure required to overcome Raw
- uneven ventilation is likely to occur
what is the purpose of setting I:E ratio
shorter inspiratory time (Ti) and longer expiratory time (Te) lead to fewer harmful effects of positive pressure
values of 1:1 and 2:1 or higher may result in increase Paw, airtrapping, and significant hemodynamic complications
review alarms:
corrective actions (high pressure obstruction, low pressure/volume leaks)
how do you set low volume alarms
5 to 10 below PIP
how do you set high volume alarms
10 above PIP
what do low volume alarms mean
useful for detecting patient disconnections and leaks in the system
what do high volume alarms mean
indication of patient coughing, increased secretions, compliance decrease, or kinks in ETT or circuit tubing
how do you set low PEEP alarms
2 to 5 below PEEP
what do low PEEP alarms mean
indication of leak in patient-ventilator circuit
how do you set low exhaled Vt alarm
10% to 15% below set Vt
how do you set low exhaled minute volume
10% to 15% below average minute volume
what problems can occur from decreased static compliance
air trapping pulmonary edema atelectasis consolidation pneumonia pneumothorax pleural effusion
how does static compliance affect the breath delivery and mode VC-CMV
PIP and Pplat increase
delivered Vt remains constant
dynamic compliance will decrease if ____ decreases and _____ increases
static compliance decrease
airway resistance increase
how does dynamic compliance affect the breath delivery and mode PC-CMV
decreased CD will:
delivered Vt will decrease
pressures increase
how does decreased CD during PC-CMV affect PIP and Vt
PIP remain constant
Vt decreased
how does decreased CD during VC-CMV affect PIP and Vt
PIP increase
Vt constant
how does decreased CS and CD with constant Raw during VC-CMV affect PIP, Pplat, Pta, and Vt
PIP increase
Pplat increase
Pta constant
Vt constant
how does decreased CD with constant CS and increased Raw during VC-CMV affect PIP, Pplat, Pta, and Vt
PIP increase
Pplat constant
Pta increase
Vt constant
how does improving CD and CS during VC-CMV affect PIP, Pplat, Pta and Vt
PIP increase
Pplat decrease
Pta constant
Vt constant
