Hi my name is Dr Joseph Becker. I'm one of the emergency physicians at Stanford University
School of Medicine, and I'm Dr. Joseph Kalanzi, an emergency medicine resident at Makerere University,
college of health science in Uganda. In this talk we're going to discuss the general
approach to troubleshooting problems and alarms for patients on ventilators. We're going to talk
about a systematic approach to examining patients and ventilators when problems are encountered.
So the objectives of this talk is to recognize commonly encountered problems
that are experienced by patients on ventilators. We also would like to have you be able to manage
and interpret ventilator alarms when they sound. And then last, but not least ,it'll be important
to know how to prevent and troubleshoot common ventilator issues as they arise.
Any decompensation in the clinical condition of the patient should prompt an immediate examination
of both the patient as well as the ventilator system. The examination of the patient should
prioritize the cardiopulmonary parts of the exam and as well the entire ventilator circuit. Taking
a look at the ventilator from the wall oxygen and power sources and tracing these lines back
through the ventilator itself and then following the ventilator tubing to the patient. Check the
ventilator tubing for occlusion or kinking. The endotracheal tube should be checked as well to
assure that the balloon is inflated and that the tube is secured in place. It's always a good idea
to document where the tube is located such as 23 centimeters at the lips. To know if the tube may
have been dislodged or moved. First actions: if a problem is not readily identified in your survey
tracing the vent power and oxygen sources through the ventilator machine and then through the tubing
to the patient, as well as the examination of the patient, then the next step should be to remove
the patient from the ventilator and to provide manual bag valve breaths with direct 100% oxygen.
Removing the patient from the ventilator and providing manual breaths with a bag valve is
a good way to exclude any potential mechanical problems with a vent
or its power source or if there is a problem with any of the ventilator tubing. As well, this
will allow you to feel how easy it is to bag the patient and if there is adequate chest rise.
A significant amount of resistance could indicate that there's an obstruction in the endotracheal
tube such as a mucus plug. Lack of resistance and chest rise could indicate that the endotracheal
tube balloon is deflated or that there is a leak. As with many things in medicine it's important
to be systematic and there's a checklist for this called the DOPES checklist as you see here.
The DOPES checklist is used to identify problems patients commonly encounter while on the vent.
We'll also look at the DOTTS checklists which is a checklist of the interventions we undertake to
address the problems we should have identified in the DOPES checklist. So as you see D stands for a
displaced endotracheal tube or a deflated cuff so these things should be checked on your examination.
O stands for obstruction, is there a mucous plug in the endotracheal tube or is the
tubing kinked. P stands for pneumothorax so examine the patient's chest and make sure you
hear bilateral oppressed sounds. If there's any doubt, perform an ultrasound or obtain an x-ray.
E is equipment malfunction, and like we said you want to assess the ventilator as well
as the associated tubing and its power supply and make sure everything is functioning appropriately.
S stands for breath stacking, which we're going to talk about in a second here, but as a source
of what we call PEEP or excessive pressure in the thorax which can create problems as well. DOTTS is
the checklist we use to organize our approach after going through the DOPES checklist. DOTTS
helps us avoid forgetting important interventions in checking the vent system. So, DOTTS stands for:
D is disconnect the patient from the ventilator or oxygenate the patient with a bag valve and
feel for resistance to bagging. T stands for tube position check for kinking abstraction
etc. T is tweak vent settings and, S sonogram- look for pneumothorax or mainstream integration.
Ventilators come in a variety of brands and levels of complexity, and alarms can be set
for pretty much any variable. This is a list of some of the more common ventilator alarms.
Keep in mind that it's important to set alarms appropriately.
An alarm should trigger a response from you. If alarms are set poorly and a ventilator is
always alarming, it will be less likely for clinical staff to actually respond to the
alarm when it sounds. Thus it'll be important to make sure alarms are set so that when they alarm
they will likely indicate there's a problem and so you'll have to get up and address it.
Many ventilators will have some form of respiratory rate monitoring.
Patients whose respiratory rate falls below a set value will trigger the alarm. Patients
who either have no respiratory drive or who have been sedated or paralyzed and thus have
lost respiratory drive, may trigger these alarms commonly unless the alarm is set appropriately.
Some vents some vents alarm at low tidal volume which can reflect apnea. Pressure alarms are
very important to monitor in the vented patient. Secretions or water in the tubing or kinks in
ventilator tubing can cause high pressure alarms. In this case you'd want to suction the patient and
look for other problems like tube kinking. If this does not fix the problem disconnect the patient
from the circuit and manually ventilate with a bag valve. Low pressure alarms are also important and
can indicate that there is a leak in the system, such as the deflated endotracheal tube balloon,
or a disconnection in the tubing. Again, it's important to systematically follow the vent tubing
from the machine to the patient to make sure that the lining is connected and that there are
no leaks. Alarms can also detect abnormalities or changes in expertise volumes. Decreasing expiratory
volumes indicate that there's a leak somewhere in the system similar to low airway pressure alarms.
High expiratory volumes can indicate patient distress agitation and high demand for air.
If there is difficulty in bagging the patient through the endotracheal tube, it will be important
to perform inline suction through the endotracheal tube. Check patient positioning as well as a
patient who is flexed with a bent neck can introduce kinking in the tubing. Mucous plugging
is a common cause of airway obstruction either in the endotracheal tube or in the larger airways.
Check the ventilator tubing for water or condensation that can collect as this may
trigger airway pressure or obstruction alarms. Low pulse oxygenation can be a symptom of a variety
of problems with the ventilator or the patient. Problems with oxygen source should be considered,
such as an oxygen tank or bottle that has run out, or problem with a central oxygen supply.
Low pulse oxygenation can as well indicate the presence of a pneumothorax
or perhaps mucous plugging or maybe just inappropriate ventilator settings.
Low oxygen levels can as well reflect an overall worsening in the patient condition such as
perhaps the development of ventilator-associated pneumonia, a plural effusion, or myocardial ischemia.
It's important to assess hypoxia and the setting of other vital signs as well as an assessment
of the entire ventilator circuit. Agitation is a frequent problem with vented patients.
In some cases agitation is a part of the problem such as in the case of
central nervous system injury, intoxication or metabolic derangement. Even just the presence of
an endotracheal tube can be a source of discomfort for many patients causing agitation. However,
agitation can also signal a problem with the ventilator settings. The evaluation of agitation
invented patients is complex and an in-depth assessment of the patient and ventilatory system
and settings should be undertaken before simply sedating or paralyzing the patient.
You're going to want to double check all ventilator settings to make sure the patients
are receiving an adequate respiratory rate and an adequate respiratory tidal volume.
And there is adequate time as well for expiration. Address any ventilator alarms or problems in
pressure or volume readings, assess the patient for any sources of pain or discomfort, if possible,
assess if perhaps different balancer settings might help to improve the patient agitation.
If no cause for patient agitation can be found, then increasing or improving sedation or pain
control should be considered. Most patients who are on a vent should be receiving some sedation,
but in the setting of agitation this may need to be increased. Pain control is critical, particularly
if the patient has injuries or other sources of pain. In extreme cases where significant doses
of multiple different sedatives have been tried and the patient agitation persists
paralysis may be considered. Paralytic should never be used without accompanying sedatives.
A patient who is on a ventilator who experiences shock or declining blood pressure perhaps
with tachycardia should have an immediate assessment of their cardiopulmonary status.
What are some of the possibilities here Dr. Joe? Well, as patients on a ventilator are receiving
positive pressure ventilation there's always going to be the risk of a pneumothorax and
then the development of a tension pneumothorax causing shock. As can be seen in the animation here,
when lung airway pressure gets high this can cause trauma to the lung and indeed a lung can burst
or pop, allowing air to escape out of the lung into the pleural space - as that pressure in the
pleural space increases with each breath, given that there's positive pressure, the increasing
pressure can occlude the return of venous blood to the right side of the heart producing shock.
So how might a clinician detect this? Well for any patient on a ventilator it's always going
to be very important to be on the lookout for pneumothorax and to be considering this in any
time your patient has vital sign instability. Of course you're going to want to initially examine
the chest and look for bilateral chest rise with each breath as well as bilateral breast sounds and
this is going to be a crucial part. The physical examination is always very important. However if
there's still concern a stat chest x-ray can be obtained to look and see if one lung has collapsed
or you can also perform bedside ultrasound which looking for lung sliding and this can
tell you if there's a pneumothorax as well. However pneumothorax is not the only way positive pressure
ventilation can cause shock, don't forget that most patients on a blender are receiving at least some
PEEP- PEEP stands for Positive end-expiratory pressure. In asthmatics and
patients with ARDS, or, acute respiratory distress syndrome the amount of PEEP can get quite high.
That's true, this can cause a significant amount of intrathoracic pressure which can impede the return
of venous blood via the superior and inferior vena cava, the right side of the heart, causing shock.
This can be particularly true in asthmatics with an obstructive respiratory pattern
who have impaired exhalation. It's always important to make sure that asthmatic patients have adequate
time to exhale and they may require more than a typical one to two i to e or inhalation
to exhalation ratio that is typically set for patients on a ventilator who have normal lungs.
When patients don't get a chance to fully exhale, we call this breath stacking- and it results
eventually in excessive PEEP or what we call auto-peep. So what can we do in these cases then?
Well auto-peep can be checked in a variety of ways, including what we call an end expiratory hold
in which the PEEP is measured directly after exhalation. If the peep measured is higher than
the PEEP that is set on the ventilator then you know there is likely some auto peep and some
excessive peep in addition to what you have set. Significant PEEP can also be seen on a chest x-ray,
and this is usually seen as very large distended lungs. There are also ways to interpret PEEP on the
pressure volume waveforms but we'll avoid these for the purposes of this discussion.
In these situations it can be necessary to remove the patient from the ventilator and just let the
endotracheal tube open to air allowing the pressure in the lungs to release. Afterwards the patient
can be reconnected to the ventilator with the appropriate PEEP and I to E ratio settings.
So there are two critical pressure variables that can be obtained on many ventilators.
One of them is the peak industry pressure or PIP and the other one is the plateau pressure
otherwise known as Pplat. The PIP is the maximal pressure obtained on inspiration
the Pplat is the pressure in the lungs and the system after an inspiration. Evaluation
of pressure volume waveforms for vented patients can yield a lot of information, but some vents do
not provide waveform analysis and some just provide numerical feedback of these values.
Knowing what abnormalities in the Pplat and PIP mean can be important for interpreting problems
with patients and events or the circuit. So for instance, if a patient has a high PIP
but a normal Pplat, this can indicate there's a problem of resistance. So for instance someone
like an asthmatic with bronchospasm, perhaps an obstruction a tube, or a buildup of secretions.
If a patient has a high PIP that or Pplat it could indicate problems of line compliance,
patient positioning, patient body habitus, auto-peep or actually a pneumothorax
And then lastly, if the PIP is low this indicates there's likely a leak somewhere in the system.
This could be a hole in the ventilator tubing or maybe a hole or a laceration
to the endotracheal tube, or maybe in a deflated endotracheal tube balloon. Patients who are vented
for anything more than a few hours will require attention to hygiene endotracheal tubes can, over
the course of hours and days, erode through lips and cause sores to the tongue and oropharynx
which can result in dangerous infections. As well attention to oral hygiene will be important to
avoid the development of oral ulceration as well as oral infections. Patients on vents should have
an oral care routine including every four to six hour chlorhexidine mouthwash and tooth brushing.
In the absence of chlorhexidine another oral antiseptic solution or sterile water may be used.
And of course patients should not be left with an endotracheal tube in place for more than two weeks.
Different hospitals have different protocols, but in general the longer an endotracheal tube is in
place, the more likely patients are to have complications. So we have come to the end of
the discussion. Some take-home points to consider and to make sure that we emphasize are: number one
be systematic in your assessment. When you're concerned about a patient or when something
happens like a ventilator alarm, check the patient, focus on the cardiopulmonary examination
and look for signs of pneumothorax or excessive PEEP. Check the vent starting from the wall with
the power source and the oxygen supply and follow these sources to the machine and then follow the
ventilator tubing to the patient. Make sure the power is actually on, make sure that oxygen is
actually flowing, and that the tank or the bottle is not empty. Check the vent and the ventilator
tubing if no problem is easily identified remove the patient from the vent and bag with 100% oxygen.
And do remember the DOPES and DOTTS checklists for identifying vent problems and common alarms,
suction if necessary, and consider causes of agitation shock or hypoxia in the vented patient.
All right well, thank you very much for joining us really appreciate it. Thank you.