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21 Cards in this Set
- Front
- Back
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Why do we need CMV?
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- failure to breathe (#1 reason)
- acute ventilatory failure - impending acute ventilatory failure - non-responsive hypoxemia |
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What is acute ventilatory failure?
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- PCO2 > 50mmHg w/ a pH < 7.25
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What is impending ventilatory failure based upon?
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- based on lab data & clinical findings that patient is progressing towards ventilatory failure
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What is non-responsive hypoxemia?
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- PaO2 < 50mmHg on an FIO2 > 50%
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What is indicated for non-responsive hypoxemia?
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- PEEP
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What are the physiologic effects of PPV (positive pressure ventilation)?
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- increased mean intrathoracic pressure
- decreased venous return - decreased cardiac output - increased ICP - decreased urinary output (ADH anti-diuretic hormone) - decreased WOB - increased deadspace ventilation - increased intrapulmonary shunt - RR, VT, I-time, & flow can be controlled - may cause stress ulcers & G.I. bleed |
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What are the modes of mechanical ventilation?
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- control
- assist - assist/control - SIMV - PS - dual modes |
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What are the characteristics of control mode?
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- all work done by ventilator
- sedation required - useful in dealing w/ ARDS especially w/ high PEEPs & inverse ratios |
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What are the characteristics of assist mode?
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- patient able to control ventilatory rate
- cannot be used on apnic patient |
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What are the characteristics of assist/control mode (most common mode)?
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- patient able to control rate as long as spontaneous rate is > than that of the machine
- machine provides majority of WOB - sedation often required to prevent hyperventilation - useful in long-term patients |
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What are the characteristics of SIMV?
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- in between positive pressure breaths, patient can breathe spontaneously
- useful for long-term patient - often used as a weaning technique - machine synchronizes mechanical breath w/ patient breath |
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What are the characteristics of PS (pressure support)?
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- does not ventilate
- ventilator functions as constant pressure ventilator - ONLY available on spontaneous modes - only applied to spontaneous breath - used to overcome initial WOB imposed by ETT & muscle weakness - can be used on any mode of ventilation that allows spontaneous breathing - can't be used in control modes |
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What do dual modes control?
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- more than one variable
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What are the steps for placing a patient on CMV?
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- establish airway
- select VT (8-12ml/kg IBW) - select mode - select rate (12-20 on initiation, 8-12 after stabilized) - set FIO2 - set PEEP - set alarms |
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How do you determine what FIO2 to place a patient on when mechanically ventilating initially?
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- start where patient currently is if already known
- 100% if unknown or post-resucitiation (titrate down as soon as possible) |
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What is CPAP (PEEP)?
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- oxygenation NOT ventilation
- keeps airways open - must be spontaneously breathing to use - generally used to treat OSA - PEEP is CPAP when used on a mechanically ventilated patient |
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What is NPPV (non-invasive positive pressure ventilation); also known as BiPAP (Bilevel positive airway pressure)?
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- similar to CPAP
- 2 levels of pressure - EPAP is your new baseline (represents oxygenation) - IPAP - the difference between the 2 pressures is known as PS - is the frontline for preventing patients from being ventilated |
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What is IMV?
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- patient receives set # of mechanical breaths
- patient can breathe spontaneously between breaths - allows for muscle usage (prevents atrophy) - allows patient to return to their baseline ABG |
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What are the advantages of IMV?
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- helps to decrease mean intrathoracic pressure
- may help avoid a positive fluid balance - allows psychological encouragement |
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What does a decrease in mean intrathoracic pressure help with?
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- helps avoid cardiac embarrassment
- increases venous return - allows for gradual weaning |
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What is the normal I:O (in:out) ratio?
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- 2400ml / 2400ml
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