mech vent Flashcards
What are side effects of increased PEEP?
- barotrauma
Increase intrathoracic pressure from mech vent will?
decrease venous return = decreased preload and decreased CO
If you have an O2 prob you can change?
- PEEP
- FiO2
if you have a vent prob you can change
- RR
- TV (if on Bipap- you can increase IPAP to increase TV) and get rid of CO2)
what is IPAP used for?
EPAP
IPAP- positive inspiratory pressure.
- ventilation PaCO2. If PaCO2 is high, increase IPAP to increase TV
EPAP- expiratory positive pressure.
- oxygenation and gas exchange PaO2. improves lung compliance. If PaO2 is decreased then increase EPAP or FiO2
how do you know if you should use BiPAP or CPAP?
look at ABG. Is it O2 or CO2 issue? if CO2 is normal use CPAP
perfusion
deliver blood to cap bed
diffusion
across membrane
what is right shift curve?
- decreased pH
- increased temp
- increased CO2
difficult pick up and the lungs but releases for tissues more easily
what do you look at when you want to wean someone from the vent?
- PaO2 and Oxy/Hgb curve
inhale is what? and on the vent its what?
- Active. - pressure intrathoracic
- on vent inhale is + intrathoracic pressure
what is a normal MAP? what does MAP indicate
how do you measure
> 65 normal
indicates best global EOP
(Diastolic x2) + systolic/ 3 =
Indicators for invasive mech vent:
QUIZ
- RR > 35
- PaCO2 > 55 with pH < 7.2
- PaO2 (with supplement O2) < 55
- severe dyspnea with use accessory muscles/trouble speaking/fatigue
- Resp arrest
- low TV/shallow resps
- cardiovascular complications (shock, HF, Hypotension)
what is the best indicator for ventilation?
PaCO2
COPD can have decrease in ? and increase in?
decrease in PaO2 and increase in PaCO2
what do we watch for on the vent?
Trends:
what did they start with? are the getting worse
Common meds for intubation
- ketamine
- Rocuronium (NMBA)
- Phenylepherine (vasoconstrict)
What to monitor pre-intubation
- position, Equip, moniotr (ECG, stats, BP…), Meds
What to do during intubation
- Cricoid pressure (maybe)
- monitor
what to do post-intubation
QUIZ**
- Bag PT
- confirm position (auscultate, chest rise, tube at teeth, CO2 detector, secure tube
- attach to vent
- confirm with X-ray
- put in OG
What is volume cycle vent?
advantage
disadvantage
Delivers preset or predetermined volume
advan: vol gas is controlled, constant O2 delivery
Disadvan: potential for excess airway pressures, barotrauma
What is pressure cycle vent?
deliver gas to the PT until predetermined system pressure is reached
- TV will vary** depending on lung compliance
- used for: when vol vent is not effective. For decreased lung compliance** and increased risk of barotrauma
when vol is a set parameter?
when pressure is a parameter?
- pressure will vary
- vol will vary
goals of vent
- decrease WOB
- support/improve vent
- improve oxygenation
- balance pH
what variable initiates change from exhalation to inhalation?
Trigger
the classification of + pressure is based on this variable
cycle
what is flow cycle vent
- set flow rate has been achieved
what is timed cycle vent
- set or predetermined time has elapsed
VT setting
6-10cc/kg normal
4-7cc/kg protective lung poor compliance
normal PEEP
5-15
Peak flow
Rate of gas delivery to a PT (40-100L/min)
I:E ratio
1:1-1:4
normal is 1:3
sensitivity
amount of - pressure the PT has to generate to initiate own breath (ex. - 2 cmH2O)
airway pressure
Set in pressure cycled modes (PSV PCV)(pressure support and pressure controlled) ;
peak inspiratory pressure (PIP) monitored in volume cycled modes (AC SIMV)
questions to ask when you see a vent
- Vent settings
- what is the PT doing?
- What are my alarms set at?
controlled breath
- PT does no work, vent does all
Assisted breath
- PT starts to breath, vent takes over
Supported breath
- Pt can do some or most of the work, vent assists or finishes the work (pressure support)
assisted AC mode
When do you use it?
What is set
What can the PT do?
What to monitor
- To initiate vent. when full vent needed
- RR, TV (PEEP, FiO2, alarms)
- Pt can breath above set RR but receives pre-set TV
- monitor RR (above set), MV (TVxRR), PIP/PLAT pressures
Assisted PC mode
When do you use it?
What is set
What can the PT do?
What to monitor
pressure controlled normal 15-25
- for decreased lung compliance
- set RR, pressure (upper limit pressure) (PEEP, FiO2, alarms)
- Pt can breath above RR but receives set pressure
- monitor: RR (above), MV, TV
Spontaneous pressure support
When do you use it?
What is set
What can the PT do?
What to monitor
- weaning mode ICU
- set pressure (boost), NO RR, NO TV (PEEP, FiO2, alarms)
- Pt has to be able to breath spontaneously
- monitor: RR, TV, MV
Hybrid SIMV + PS
When do you use it?
What is set
What can the PT do?
What to monitor
- weaning PACU
- Set RR, TV (PEEP, FiO2, Alarms)
(PS- added on spontaneous breaths) - PT can breath above RR but received OWN TV
- monitor: RR (above), MV, PIP/PLAT pressures
All vent settings common assess
- ABGs
- WOB
- alarms
Ppeak
pressure airway peak -
calc PEEP + set pressure = Ppeak
PIP
- the highest airway pressure generated by the delivery of the set Vt
- elevated inspiratory pressure. indicates changes in lung compliance or something obstructing airflow delivery (secretions)- the whole system
- pressure with each breath in entire system (lungs, tubes, ETT…)
Normal is < or = 50
side effects of PEEP?
barotrauma and increased intrathoracic pressure
Plat pressure
pressure at the end of inhalation, like holding your breath
- lung compliance
- norm < or = 30
settings are?
on the bottom screen
what is PT doing?
on the left side screen
SIMV + PC
synchronized intermit mandatory vent
- assist with spontaneous breathing
- the PT can initiate breaths in between mandatory breaths
- PTs own TV, varies by PT lung compliance
- lung compliance reflects pressure
- inspired pressure varies
- PC normal 15-25
when do you extubate from SIMV?
wean PS down to 5 for 12-24hrs and then can extubate (5 is min)
TV is set at …… for lung trauma
4-7cc/kg, when trying to protects against lung trauma
sensitivity determines
how much effort the PT has to make to trigger a breath or gas delivery from the vent
Peak or PIP is…
- determines the flow rate for gas to the PT
- may be 40-100L/min
For PT on AC mode, which changes to vent setting would decrease PaCO2?
increase RR or TV
on PC vent, which changes would you make to decrease PaCO2?
increase set pressure
increasing PEEP on a vent…
- increases baseline intrathoracic pressure
- can decrease venous return and preload
in AC mode, what is not monitored
set pressure
in PS mode, what is not monitored?
Set Tv
in PC mode what is not monitored?
Set Tv
Which parameter occurs in SIMV but not in AC?
spontaneous MV
in PCV and PSV, _______ influences_______ so minute vol must be closely monitored
compliance, TV
what does it mean if PIP increases?
lung compliance is decreasing
Pt is getting 10cm H2O PSV, exhaled TV has been decreasing from 450–> 375, what does that mean for lung complinace?
decreasing
Pt getting 10 cm H2O PSV, in 3 hrs their RR increased from 14–> 26, what does this indicate?
not enough PS
on SIMV mode, in the last 3 hrs Vt has decreased and their spontaneous RR has increased. what might this indicate?
Pt is fatiguing
Pt is vented with PCV with PS of 20cm H2O, iTime 1 sec, RR 16. you care concerned that lung compliance is deteriorating. What parameters will provide best indication that this is occurring
Exhaled TV
Responses to mech vent
-barotrauma
- hemodynamic alterations
- fluid retention (ADH secretion)
- O2 related issues: atelectasis, toxicity
- upper airway damage
-
Nurse management of mech vent
- assess PT/moniotr/alarms
- troubleshoot alarms
- know complications of mech vent
vent alarm always start at the?
PT. if in doubt of airway patent/inadequate vent. the bag the PT with O2 connected
- work from PT to vent
apart from secretions what else causes high pressure alarm?
- kink vent tube
- biting on ETT
- bronchospasm
low pressure alarm causes
- loose connections
- low cuff pressure/cuff leak
- crack in tubing
cause of low exhaled TV alarm
- PT tiring in weaning mode
- cuff leak, low cuff pressure
- bronchospasm
Low VT alarm and Pt cough and becomes restless, you?
listen to breath sounds and suction
increasing PEEP will?
watch for? 3
- increase intrathoracic pressure and falsely increase CVP
- drop in BP
- preload
- barotrauma
what would you want to give if you increase PEEP and have a low CVP?
NS bolus to increase preload
Pt is on PCV and has resp acidosis with mild hypox, what changes do you want to make
increase set pressure and increase PEEP
increased PEEP = increased intrathoracic pressure = decreased venous return
PT on PCV and has resp acidosis, what do you change
increase pressure support
Pt on ACV set RR 20/24, Vt 350, FiO2 0.35, PEEP 5.
Pr has resp alkalosis
what is most approp intervent?
decrease Vt
what causes barotrauma?
rising PIP
keep < 50!!
more important to watch the trend
how does a fluid imbalance happen when vented?
positive pressure decreases venous return (increased intrathoracic pressure). This triggers the RAAS and increased ADH secretion.
- watch urine O/P, CVP, and other indicators of preload
Pt has resp acidosis with mild hypoxic. On PC. what is the prob and what do you change?
Prob. Ventilation
increase the pressure support will indirectly increase the Vt
Decreasing PEEP, you need to watch for potential for?
changes in lung compliance
positive pressure vent can lead to what lung complications?
- volutrauma
- pneumothorax
mech vent impacts GI system by?
- increase risk gastric ulceration and gastric distension
absorption atelectasis?
when FiO2 is close to 1.0 (100%)
high levels of O2 can lead to? 5
- release of free radicles
- increase lung inflam
- atelectasis
- pulm fibrosis
- localized lung edema
how do you minimize high levels of O2
use or increase PEEP
Pt has metabolic acidosis with hypoxemia
FiO2 is 0.8 on PC 15, PEEP 5, Vt 250-325, RR12
potential complication for oxygen toxicity
increase PEEP so that you can decrease FiO2
Airway management
- suction
- warm humidified air to thin secretions (tenacious secretions)
- mucolytics (aerosolized mucomyst)
- reposition to mobilize secretions
- bronchodilators to decrease airway resistance
suctioning
- If PIP increasing
- pre-oxygenate for 30-60 sec 100%- for PT who desat easy or have high O2 needs
- insert cath no longer than carina
- less than 15 sec max
- cont not int
increase in PIP could be from?
decreased compliance
what are the concerns with an increasing PIP for a PT on ACV
- barotrauma
- worsening pneumonia
beside changing vent settings, how can you decrease PIP?
- provide sedation
- chemically paralyze
- provide verbal reassurance
- ensure adequate analgesia
when switched to PC what would you monitor for lung compliance?
Tv
what do you want to change with partial comp metabolic acidosis
- decrease FiO2 and decrease PC
weaning methods
- spontaneous breathing trials** ICU
- progressive decrease in the level of pressure support in PSV** ICU (NOT decreasing PC- pressure)
- progressive decrease in vent-initiated breaths in SIMV mode ** PACU
- decreasing SIMV RR
SBT
lasts: 30-120 min
- gradual decrease PSV to 5 bfr extube
Short term- from OR: can use T-tube, CPAP, or low PS. Low rate SIMV 30 min then extubate
the RSBI calc readiness to wean
rapid shallow breathing index
RR and TV
RSBI is 40-50 (RR/Tv)
<105
indicates she is ready to be weaned
essential criteria for indicating PT readiness to wean
- PEEP 5-7
- FiO2 < or = .5
- low to no vasopressors
- condition resolved or almost resolved
- ability to initiate insp effort
a - inspiratory force of _____ and a VC of _____ ml/kg are parameters that are indicative of readiness to wean
< -10, >10
how do you know if a PT is not tolerating the SBT
- sweating, agitation, anxiety
- SpO2 < 88
- PaCO2 increased by 10mmHg
- HR >140
- RR> 35 for > 5min with increased WOB
- SBP <90 or >180
for long-term vents, approp weaning?
- regular decreases in PS
- PS followed by AC rest periods
- complete when able to breathe spontaneous for 24 hrs
common causes of failure to wean:
- source of resp failure not corrected
- fluid vol overload
- cardiac dysfunction
- neuromuscular weakness
- delirium
- metabolic disturbances
- anxiety
not ready to be extubated
- pH< 7.25
- PaCO2 51
mech vent CVP goal
Now 8-12
