Jamie - I don't know if any of this will be helpful for you to know more about the vent but it is what I typed out to put in Lil D's book so that all the nurses have the same amount of basic knowledge about the vent. Sorry in advance for the weird formatting, I copied and pasted from Excel and on top of that I had to change his name from his first name to D. If it's not helpful, I'm sorry for making you read all of that!!
D is on the LTV-1150.
He is vent dependent. He can only tolerate being off the vent for about 45-60 seconds!
D is on oxygen at all times through the vent. Minimum flow is 2LPM.
ALWAYS DISCONNECT D FROM THE VENT WHEN MOVING FROM BED TO WHEELCHAIR,
WHEELCHAIR TO BED, WHEELCHAIR TO TREATMENT TABLE, ETC.
The vent settings are as follows:
Mode: Assist Control
Control: Pressure Control
Breath Rate: 15
Tidal Volume not used
Pressure Control: 27
Inspiratory Time 0.8
Pressure Support: not used
High Pressure Alarm 45
Low Pressure Alarm 5
Low Minute Volume Alarm not used
The LTV-1150 compensates for the PEEP. This means that the PIP (Peak Inspiratory Pressure)
should be 34 which is the Pressure Control of 27 + the PEEP of 7.
D's PIP is usually between 32 and 37.
The LTV-1150 is very sensitive to water in the line. If you hear the vent cycling breaths, check the
circuit first. Let any water flow into the water trap. 95% of the time, this stops the vent from cycling.
If the water trap is not at the lowest point, you may need to tie part of the circuit to the bed.
The humidifier should not be allowed to get more than half empty.
The water trap should not be allowed to get more than half full.
Please empty the water trap into the purple water bottle. Do not dump water into the garbage can.
Please empty the purple water bottle at the end of your shift.
Only use distilled water to fill the humidifier.
Extra distilled water is under the bed.
Any time a new circuit is put on, it must be leak tested. If you do not know how to do this, please
ask. This information is also available in the LTV-1150 manual under "check-out tests."
The information scrolling across the display is what the D and the vent are actually doing at that
time. These are not settings!
In general, D's info is as follows:
f (frequency of breaths) 15bpm up to 20 bpm
Vte (exhaled tidal volume) 50mL - 275mL
VE (minute volume) 2.2L - 4.5L
I:E (inspiratory expiratory ratio) 1:4.0
LMV OFF (this is alerting you that the LMV alarm is off)
PIP (peak inspiratory pressure) 32 - 37cm H2O
MAP (mean airway pressure) 12cm H2O
PEEP (positive end expiratory pressure) 6-9cm H2O
What these numbers mean:
TThe frequency of breaths should be at least 15bpm. It can be 12 or 13 if he has held his
breath. If it is below 15bpm for more than one minute, assess for chest rise. Give one
manual breath and observe. If no chest rise, immediately assess patency of airway.
If trach is in place, give breaths with Ambu-bag until back-up vent is on. If airway is not
patent, begin emergency trach change procedures. If the frequency is greater than
20bpm, check the water trap and make sure that it is not too full. Check the circuit for
standing water in the line. Drain water into circuit. That should alleviate the issue and
the breaths per minute delivered by the vent should start dropping immediately. If that
does not correct a high frequency of breaths, assess D immediately and determine
if he needs to be moved to the back-up vent or be bagged.
The Vte is the tidal volume that is exhaled during the expiratory time. This volume is
measured at the top of circuit at the wye. This number changes with each complete
breath cycle. If D is breathing very shallowly, it will be in the double digits.
If the Vte is very, very low such as 0, single digits or less than 40mL, make sure the
circuit is properly connected and secure to the trach. There are several connecting
points. Start at the trach and move down one branch of the circuit until you get to the
vent. Move down the other branch until you get to the humidifier. Assess D for
equal chest rise and determine necessary interventions.
The VE is the exhaled tidal volume over the last 60 seconds. This number is updated
with each breath cycle. D generally is in the mid 3's but has gone as low as 1.8L and
as high as 4.9L. A VE that is less than 1.0L is too low. Verify that the circuit is properly
connected and secure to the trach as outlined above. Assess D and determine if
The I:E Ratio is the ratio of time for inhalation to the time for exhalation. It is almost
always 1:4.0. This does NOT mean that he is inhaling for one second and exhaling for
four seconds. If he is not breathing over the vent (f=15bpm), it means that he is
inhaling for 0.8 seconds and exhaling for 3.2 seconds. This would give him a time of
four seconds for a complete breath cycle x 15 bpm=60 seconds. The I:E ratio should
always be 1:something. If the vent was cycling (water in the line, open circuit for
suctioning, etc.), you may briefly see it inverted. That should be very brief. If the I:E ratio
is inverted for too long, D will start to retain carbon dioxide.
LMV OFF is just a reminder that the Low Minute Volume Alarm is off.
The PIP is the peak inspiratory pressure. This is the highest pressure during the
inspiratory phase and the first few milliseconds of the expiratory phase. His settings
for PIP should have him right around the 34cm H2O mark. To figure out what PIP should
be, add the Pressure Control number (27) to the PEEP setting (7). D is generally
between 32 and 37cm H2O. The high pressure alarm will sound for a PIP of 45 or above.
The low pressure alarm will sound for a PIP of 10 or below.
The MAP is the mean airway pressure. This number is almost always at 12cm H2O.
To be perfectly honest, I don’t know the significance of this number but when I found out
I will update this page.
The PEEP is the positive end expiratory pressure. The PEEP is set to 7cm H2O but the
display is showing the actual PEEP. The PEEP usually varies between 6 and 9 cm H2O.
The high PEEP alarm will trigger for a PEEP of 12 or above. The low PEEP alarm will
trigger for a PEEP of 4 or below.
If you are filling the humidifier, you will most likely trigger the DISC/SENSE alarm. This means that
the ventilator has sensed a disconnect in the circuit.
The HIGH PRES alarm sounds when there is a lot of resistance in the lungs. This can be caused
by many things but is usually because D is holding his breath or he needs to be suctioned. The
first thing you should do is assess and suction his trach.
The LOW PRES alarm sounds when there is low or no resistance in the lungs. This can also be
caused by many things including being disconnected from the vent and an accidental decannulation.
Immediately check that all parts of the circuit are properly connected and that D has a patent
If you are suctioning, you will trigger the LOW PEEP and LOW PRES alarms.
DO NOT SILENCE ALARMS UNLESS YOU KNOW WHAT HAS CAUSED IT! This is especially
true at night. If I hear the vent alarming, it will wake me up. If you have an emergency but have
silenced the alarm so you don't have to listen to it, I won't know that something is still wrong!