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Resp 2.7 III
basic ventilator PP
Question | Answer |
---|---|
Mode | How we deliver the breath. How the machine will deliver insp and create expiratory |
sensitvity | determine ease with which pt can begin inspiration (flow or pressure sensitivity) |
Inverse IE ratio | pt usually sedated |
PIP Peak inspiratory pressure/ MIP | Pressure that is required to deliver the set volume on the ventilator. (HOW MUCH PRESSURE YOU NEED TO VENTILATE THE LUNG) |
MAP mean airway pressure | average airway pressure over a resp cycle an increase in MAP helps with oxygenation. You use it if there is to much dead space (to much pressure) |
Negative pressure | Creates a negative extrathoracic pressure |
Positive pressure | creates a positive intrapulmonary pressure |
Internal circuit | pathway for air inside the machine |
external circuit | has exhaltion valve which functions to direct the flow of the gas to the pt wye. |
External circuit will not | function properly without a exhalation valve, machine would not deliver a positive pressure breath |
Assist | pt initiates all breaths (machine is not set to deliver timed breaths) |
control | machine is set to deliver ALL breaths based on time, pt CANNOT take assisted breaths |
What makes the ventilator begin a breath for the pt | time, pressure, flow, volume triggers |
Flow triggering | used instead of pressure triggering, more senstive to pt effort. Decreased WOB, base flow rate is set through the pt circuit., as pt reduces that flow by an amount (trigger flow) machine delivers pt breath. |
The variable that is measured and used to end expiration | cycle variable |
Pressure cycled | inspiration ends when a pre set pressure is reached. pressure stays constant |
Volume cycled | inspiration ends when a pre set volume is delivered. Volume and flow are constant. Needs to hit Vt to exhale |
Time cycled | inspiration ends when a set time expired. Pressure is constant. |
What effects expiratory time | flow, rate, volume |
Flow cycled | inspiration ends when a min flow is met. Breath in and when you are filled that flow drops (stops) and makes you exhale |
Pressure limited/time cycled | allows the therapist to preset peak airway pressure and insp ends due to the set time. Tidal volume is variable depending on total system resistance and compliance |
How pressure limited/time cycled works | ventilator adjusts flow to meet set pressure, flow is tapered or decreased, |
IE ratio limit | prevents the ventilator from delivering breaths with an IE ratio of less than 1:1 |
Pressure limit | sets a maximum inp pressure that can be delivered to the pt. Stops inspiration, (SAFETY PRESSURE LIMIT WE SET) |
Inflation hold (plateau) | at peak insp, holds the pressure or volume for a period of time, increase IE ratio. |
Pressure limiting relief valve alarm | Releases any pressure in the system by venting any volume remaining (ALLOWS VOLUME TO ESCAPE) |
PEEP | on expiration, pressure is held at an elevated baseline above atmosphere, WORKS BY INCREASING FRC. (RAISE BASELINE,OPENS AIRWAY) |
CPAP | when used on ventilator, it is same as PEEP except that the pt must be taking only SPONTANEOUS breaths. |
Assist/control | use when pt is breathing some on their own but not effiecient enough |
assist | pt must be initiating breaths on their own |
control | pt cannot initiate breath on their own |
IMV/SIMV | pt must be breathing spontaneously, used as weaning mode |
Pressure support | affects spontaneous breath only, used with SIMV or CPAP mode |
Pressure control | pressure limited, time cycled (USE PRESSURE LIMIT THAT PRESSURE AND TIME CYCLES IT OFF) |
IMV | ventilator is set to deliver a specific # of breaths at a set volume. In btwen the set # of breaths the pt can take as many additional OWN breaths as they want (whatever volume they get is what they get) |
SIMV | same as IMV but if pt has started to take OWN breath and it's time for a machine breath the machine will wait and allow pt to take control. (will not stack breaths) |
CMV continous mandatory ventilation | assist/control mode on some ventilators, each breath delivered to the pt is at the volume set on the machine |
PSV pressure support ventilation | NO SET, pt has control of RR and volume. FLow is provided at a level necessary to acheive the set pressure. Pressure is then maintained throughout inspiration. Machine cycles off when flow delivered slows down. |
IN PSV what effects volume | muscle, pressure, flow, compliance and resistance |
Flow cycled on PSV | machine cycles off when flow slows |
Pressure limited on PSV | will not go above pressure set |
Assisted ventilation on PSV | breath only happens when pt triggers machine |
On PSV | when breath starts it helps push up until it drops (flow drops) |
Levels of 7 and below | overcome airway resistance and make breathing easier. They will be getting that volume on their own |
Levels of 7 and above | can add to spontanous tidal volume |
Goal of pressure support PSV | overcome airway resistance, increase until WOB decreases and ventilatory pattern improves |
If you increase pressure you will get | close to volume that is set |
How does PSV help pt | Decrease WOB, increase spontaneous tidal volume, can decrease RR, increase Vt, reduces resp muscle activity, can decrease oxygen consumption (how body is using it) |
Pt not breathing on their own (spontaneously) or not strong enough to initiate an assisted breath | Use assit/control or CMV |
Pt strong enough to assist ventilator in assist/control use | SIMV |
If pt's tidal volume is large but has low PaO2 use | PEEP or CPAP |
Pt strong enough to assist ventilator but has low Vt in spontaneous breaths use | PSV |
When oxygenation is poor and pressure control does not work try | inverse ratio ventilation |
The key to selecting flow pattern is to select the one that will | best ventilate the pt, low peak airway pressure, low mean airway pressure, IE ratio of at least 1:2 or less |
On Volume cycled ventilators if you increase the flow | decrease I time/increase E time |
On volume cycled ventilators if you decrease the flow | increase I time/decrease E time |
If you increase the volume | increase I time/ decrease E time |
if you decrease the volume | decrease I time/ increase E time |
If you the pt fights the machine | work of breathing will increase |