review of modes of mechanical ventilation l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Review of modes of mechanical ventilation PowerPoint Presentation
Download Presentation
Review of modes of mechanical ventilation

Loading in 2 Seconds...

play fullscreen
1 / 74

Review of modes of mechanical ventilation - PowerPoint PPT Presentation


  • 161 Views
  • Uploaded on

Review of modes of mechanical ventilation. By Elizabeth Kelley Buzbee A.A.S., R.R.T.-N.P.S., R.C.P. In A/C mode there are two ways to trigger the breath. What are they?. question. ANSWER:. In A/C mode, the ventilator has Time triggered Patient triggered. question.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Review of modes of mechanical ventilation' - adara


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
review of modes of mechanical ventilation

Review of modes of mechanical ventilation

By Elizabeth Kelley Buzbee A.A.S., R.R.T.-N.P.S., R.C.P.

answer
ANSWER:
  • In A/C mode, the ventilator has
  • Time triggered
  • Patient triggered
question4
question
  • Identify the two most common patient triggers for mechanical ventilators in A/C mode
answer5
ANSWER:
  • Pressure trigger
  • Flow trigger
question6
question
  • A/C mode is considered one of the CMV modes.
  • What is a CMV mode and why is A/C classified as a CMV mode?
answer7
ANSWER:
  • A/C mode is a CMV mode because it handles 100% of the work of breathing. The patient can trigger a breath, but all breaths are controlled by the ventilator .
  • CMV modes include: A/C in PC or VC
  • One of these modes is used to rest the patient who is in respiratory failure
  • He does no work at all.
question8
question
  • Identify the most common initial ventilator setting used with the patient in respiratory failure who needs to rest?
answer9
ANSWER:
  • A/C or VC modes will rest the patient
  • We can also use these modes with sedation and paralysis to “Control” the patient
question10
Identify the mode one would select for initial ventilation of the patient with COPD or with asthma who needs to rest?question
answer11
ANSWER:
  • We would select SIMV with a rate of 10-12 to rest this patient while minimizing chances of air trapping that can happen during A/C.
  • If the patient’s exhalation is too long, we may need to decrease the rate even more.
question12
question
  • Your patient is on A/C 10 and he is breathing 15bpm.
  • What has happened to his inspiratory time?
  • What has happened to his expiratory time?
  • How can you correct this situation?
what has happened to his inspiratory time
What has happened to his inspiratory time?
  • The inspiratory time is established by the inspiratory flow rate and flow pattern.
  • If those knobs don’t change, then the inspiratory time doesn’t increase or decrease.
what has happened to his expiratory time
What has happened to his expiratory time?
  • Because the rate increased from 10 to 15 bpm, the patient’s cycle time decreased.

Cycle time = 60 seconds / rate

60 / 10 = 6 seconds

60 / 15 = 4 seconds

  • As the cycle time decreases, and the inspiratory time stayed the same, the expiratory time decreased
how can you correct this situation
How can you correct this situation?
  • A couple of ways:
  • Increase the flow rate to decrease the inspiratory time, this gives you more time to exhale
  • Change the patient from A/C to SIMV if you want him to breathe
  • If you don’t want him to breathe, give him sedation and paralytic agents to return him to ‘Control’
question16
question
  • What is the advantage of control mode?
answer17
ANSWER:
  • Controlling the patient will control the VE, thus the PaC02.
  • When the patient breathes on A/C or SIMV he will alter the VE which will change the PaC02.
question18
question
  • What is the difference between SIMV and IMV?
answer19
In IMV, the patient will get his time-triggered breaths right on schedule. If he happens to be exhaling during his spontaneous breath, then he will ‘stack breaths.’ this leads to air trapping & patient discomfort.

In SIMV, the patient’s time-triggered mandatory breath will come in just a fraction of a second early so that the patient and the ventilator are ‘synchronized’ to avoid stacking breaths

ANSWER:
question20
question
  • Under what circumstances do we move the patient to PSV?
answer21
ANSWER:
  • we add PSV to the SIMV so that the patient can establish a spontaneous VE without increasing his respiratory rate to a dangerous level.
  • We also select PSV when we want to help the patient breathe, but still allow him to use his own muscles.
question22
question
  • What is the advantage of SIMV with PSV over SIMV alone?
answer23
ANSWER:
  • In PSV, because the patient selects his own VT, inspiratory flow rate and his own VE, his muscle strength and co-ordination are encouraged
  • Because the PSV ’s VT are larger than the patient could get with spontaneous breathing, his WOB is not as excessive as if he was doing all the work, but it is more than if the ventilator was doing all the work
question24
question
  • How do we select the correct PSV pressure?
answer25
ANSWER:
  • There are three methods:
    • Set up the PS pressure to get a VT of 10-15 ml/ kg IBW
    • Titrate the PS to get a spontaneous respiratory rate of less than 25 bpm
    • Give just enough PS to overcome the resistance to the endotracheal or the tracheostomy tube
question26
question

Compare PC ventilation to VC ventilation

answer27
Answer
  • in PC ventilation, you set the PIP and the VT will vary based on the patient’s compliance and RAW
  • In VC ventilation, you set the VT and the PIP will vary based on the patient’s compliance and his RAW
question28
question
  • Describe the effect on the return VT of the patient on VC whose PIP has reached the high pressure limit?
answer29
answer
  • In VC ventilation, when the patient reached the high pressure limit, the breath is immediately cycled off, and exhalation starts.
    • Audible and visual High pressure alarms go off
    • VT thus VE drops
    • PIP rises, thus PAW rises
question30
question
  • Describe what happens to the patient on PC ventilation when he reaches the set PIP?
answer31
answer
  • A patient on PC ventilation, who reaches his PIP will continue to get the breath at that pressure until it is time-cycled off.
  • If however, if something happens so that the patient reaches the high pressure alarm [which is set higher than preset PIP], his breath with still end immediately on PC just as it does on VC
question32
question
  • Compare CPAP mode to PSV
answer33
ANSWER:
  • In CPAP, the patient is breathing spontaneously. His VT, inspiratory flow rate and Ti are all determined by the patient. His PAW and the baseline pressure are pretty much the same.
  • In PSV, the patient triggers a pressurized breath that rises above the baseline. Again, this patient controls his own VT, inspiratory flow and Ti, but in this case the PAW is lower than the PS pressure because there is more difference between baseline and PS pressures.
question34
question
  • In what ways are CPAP and PSV max the same?
slide35
CPAP and PSV max both require a patient with an intact ventilator drive, & enough muscle strength to create a VE that can get the PaC02 to normal levels
  • In both of these modes, the clinician must establish [1] VE alarms that will warn of apnea and [2] high respiratory rate alarms to warn of possible fatigue
question36
question
  • When do we select PC ventilation rather than VC?
answer37
ANSWER:
  • When VC ventilation has failed due to excessive PIP or Pplateau and there is real danger of barotrauma or decreased CO.
  • In infants or small children who have gross air leaks around uncuffed endotracheal tubes
question38
question
  • Identify the indications for SIMV or IMV?
answer39
ANSWER:
  • To wean the patient by increasing his work load gradually
  • As an initial ventilatory mode for COPD and asthma patient to minimize airtrapping
  • To decrease the negative effects of A/C mode on the cardiac output
questions
questions
  • Identify indications for CPAP
answer41
CPAP or N-CPAP for obstructive sleep apnea

Treating refractory hypoxemia without respiratory acidosis or hypercapnia

Weaning modality just before the patient is extubated

Means of keeping a patient ‘off’ the ventilator for more than 2 hours without risking atelectasis

ANSWER:
question42
question
  • Describe IRV?
answer43
ANSWER:
  • IRV is ‘inverse ratio ventilation’ Which is a mode where ventilator is set up so that the inspiratory time exceeds the expiratory time making the ratio 1:1 up to 4:1
question44
question
  • Identify an indication for IRV.
answer45
ANSWER:
  • IRV is indicated in patients with poor compliance and normal RAW who have failed conventional ventilation by having PIP so high there is a real risk of barotrauma or decreased CO.
question46
question
  • Explain what happens in ‘Bilevel ventilation’
answer47
ANSWER:
  • In bilevel ventilation, the patient breaths at a high level of CPAP that drops down to a lower level of CPAP periodically so that the patient can get rid of excessive C02
question48
question
  • What happens to the patient on Bilevel ventilation if he becomes apnic?
answer49
If the patient on bilevel ventilation has been set up properly, as he stops breathing, the changes between high CPAP and low CPAP now are changes between a PIP and a PEEP—in other words, the patient reverts to PC ventilationANSWER:
question50
question
  • How does bilevel ventilation compare to APRV?
answer51
ANSWER
  • These modes are identical except that in APRV, the patient breaths at the higher CPAP level for a longer time than he breaths at the lower CPAP level.
  • In Bilevel ventilation, the time spent at higher CPAP is less than at lower CPAP
answer53

ANSWER

The patient on APRV who goes apnic will now have alternating high and low pressures. He will basically revert to PC – IRV.

question54
question
  • You have a blood gas that shows the pH is acidic due to a higher PaC02.
  • What parameters do you adjust to correct this?
answer55
ANSWER
  • To control the PaC02 you manipulate the VE. Parameters that manipulate the VE are the respiratory rate and the VT
  • Once the PaC02 returns to normal the pH will return to normal
question56
question
  • You have an arterial blood gas in which the patient’s Pa02 and Sa02 are both lower than normal. How do you adjust the ventilator to treat hypoxemia?
answer57
ANSWER:
  • To treat hypoxemia you increase the Fi02
  • If the Fi02 changes don’t work—or your Fi02 is at a toxic level, then you increase the PEEP level
question58
question
  • If your patient had the following ABG what would you do to the ventilator?
  • pH 7.47
  • PaC02 30
  • Pa02 45
  • HC03- 26
answer59
Answer
  • To correct the low PaC02, you need to decrease the VE
  • That will fix the pH too
  • To correct the low Pa02, you need to increase the Fi02 or if it is already at 50% start the patient on a PEEP of 3-5 cmH02
case studies
Case studies
  • Patient is a 65 year-old WM with respiratory failure secondary to viral pneumonia. He has a history of COPD. He is alert and anxious with a respiratory rate of 35 bpm.
    • What ventilator mode [modes] might work with him?
    • What parameters would you monitor?
    • What are the problems associated with the mode you selected?
    • What are the advantages to the mode you selected?
what ventilator mode modes might work with him
What ventilator mode [modes] might work with him?
  • He needs to rest, so A/C might be a choice but because he is at risk for airtrapping, one might best select SIMV for his initial mode
what would you have to monitor with this mode
What would you have to monitor with this mode?
  • Vital signs for increased WOB or compromise of Cardiac output
  • Sp02 for oxygenation
  • pH and PaC02 for acid/base balance
  • BBS to make sure his breath ends before the next breath comes in to avoid air trapping
  • monitor flow/time curve for auto-PEEP and air trapping
what are the problems associated with the mode you selected
What are the problems associated with the mode you selected?
  • SIMV will result in the patient controlling some of the VE, you will lose fine control over the PaC02—unless you sedate and paralyze him
    • Then your patient will get muscle atrophy after a few days of this CMV
  • As the SIMV rate is dropped the patient must assume more of the VE, , and we don’t want his spontaneous respiratory rate getting too high if his VT is too low
what are the advantages to the mode you selected
What are the advantages to the mode you selected?
  • SIMV will minimize chances of air trapping,
  • it will help him keep his muscle strength
  • maintain his ventilatory drive as long as the Pa02 and PaC02 stay at his baseline
case study 2
Case study # 2
  • Patient is a 25 year-old BF suffering from a closed head injury. The doctor wants to keep the PaC02 at 25-35 mmHg and the Pa02 110-120 mmHg to minimize cerebral edema. Her breath sounds are clear and bilateral when you bag her at a rate of 15 bpm and with 100% Fi02.
    • What ventilator mode [modes] might work with her?
    • What would you have to monitor with this mode?
    • What are the problems associated with the mode you selected?
    • What are the advantages to the mode you selected?
what ventilator mode modes might work with her
What ventilator mode [modes] might work with her?
  • In situations where the clinician needs complete control over the PaC02 like this one, a control mode of some kind is required. A/C with VC is best
  • Sedation and paralysis is mandatory
what would you have to monitor with this mode67
What would you have to monitor with this mode?
  • In closed head injuries we worry about sudden changes in the systemic BP because this can change blood flow in the head.
  • We watch the PAW: PIP and PEEP changes can alter the thoracic pressure thus the blood flow from the head
  • We watch the Sp02 for hyper-oxygenation
  • We watch the VS for s/s of altered blood pressure
what are the problems associated with the mode you selected68
What are the problems associated with the mode you selected?
  • If the patient were to wake up and start to breathe, he can drastically alter:
  • his VE thus his C02
  • He could air trap as his respiratory rate rises without the flow rate rising to keep the I:E the same
  • As he fights the ventilator, his PAW can rise which can alter his blood flow from his head
what are the advantages to the mode you selected69
What are the advantages to the mode you selected?
  • You have complete control over the PaC02 so that there are no alternations in cerebral blood flow
  • You have complete control over the PAW so that there are no changes in the cerebral blood flow
case study 3
Case study # 3
  • Patient is a 55 year-old LAF with respiratory failure following cardiac arrest. She is apnic and unresponsive with a low CO and diffuse crackles in both lungs
    • What ventilator mode [modes] might work with her?
    • What would you have to monitor with this mode?
    • What are the problems associated with the mode you selected?
    • What are the advantages to the mode you selected?
what ventilator mode modes might work with her71
What ventilator mode [modes] might work with her?
  • While CPAP, NIPPV or PSV might be indicated for CHF which might well be part of this patient’s problem, she is apnic
  • She needs to be intubated and ventilated
  • VC or A/C is initial ventilator mode for her.
  • Post-CPR patients are best started with Fi02 100% then get a gas and titrate later
what would you have to monitor with this mode72
What would you have to monitor with this mode?
  • Sp02 for oxygenation and good peripheral perfusion
  • BBS and P plateau for changes in lung compliance due to CHF—or fluid over load during CPR
  • VS and heart monitor for cardiac arrhythmias
what are the problems associated with the mode you selected73
What are the problems associated with the mode you selected?
  • If the patient were to wake up and breathe faster, she will increase her VE which will alter her PaC02
  • If she breathes too fast, she alters her I:E ratio which can decrease venous return to the heart
  • Each breath on A/C will result in higher intrathoracic pressures- this could confuse her body’s control over urine production and blood pressure
what are the advantages to the mode you selected74
What are the advantages to the mode you selected?
  • We control her PaC02 and her Pa02.
  • She rests
  • Her WOB is decreased and that will decrease the work on her heart
  • As long as she is controlled by sedation and paralysis, her intrathoracic pressures stay the same so that ventilation cannot alter the blood pressure