DR. SUSAN WILCOX: This video will cover management specific to COVID-19.
Much of this material has been covered in other videos.
However, given the importance of COVID-19,
we wanted to provide one video that is a comprehensive resource
to collate the information that we have at this date.
Patients with COVID-19 are presenting with hypoxemia as the major issue.
In this example, the patient had an SPO2 of 92% on room air.
While that's mild hypoxemia, with any movement at all,
the patient desatted profoundly down to the 80s.
Other clinicians are reporting that they're
seeing patients present with SPO2 in the 70s, 80s, and even lower on room air.
The patients are usually oxygen responsive, but not to the degree
that we would like to see.
Here's an example of x-rays for a patient with COVID-19.
The first x-ray was his x-ray when he presented to the emergency department.
You can see that he has bilateral patchy infiltrates, and he did
have an oxygen requirement at that time--
approximately 2 liters nasal cannula.
The patient was admitted to the regular medical floor in reasonable condition.
However, unfortunately, over the next 12 hours,
he had a significant decline in his respiratory status.
And he was admitted to the intensive care unit.
The subsequent x-ray is his chest x-ray about 36 hours
after the initial presentation.
Showing significant progression of the bilateral patchy infiltrates,
this x-ray was taken right before he was intubated.
One of the major controversies in taking care of patients with COVID-19
is the supplementation of oxygen
in a non-invasive manner. We know for other patients,
high flow nasal cannula is an excellent means of supporting patients
with hypoxemic respiratory failure.
It works very well and is associated with improved outcomes.
The problem is that we worry about aerosolizing the virus.
The concern is that if we provide high flow,
this could result in more infections in health care workers and other people
around.
Similarly, we have great experience using non-invasive positive pressure
ventilation in many patients.
Especially those with COPD and CHF.
In this patient population, recruitment is a major issue.
And so it seems intuitive that non-invasive ventilation may be
beneficial to recruit these patients.
However, the worries about aerosolization remain.
And they're probably even more significant with non-invasive positive
pressure ventilation.
As such, different authors and different societies
have had different recommendations about how we should approach this.
And each institution is cultivating their own approach.
Many are recommending that we forgo all of these methods,
and go directly to early intubation.
There are some reporting that they're seeing
improved outcomes with early intubation for these patients.
And so, many are saying that once a patient is
getting beyond 6 liters of nasal cannula,
early intubation is the next right step.
When these patients present, they're often sitting upright,
using significant negative inspiratory force to maintain their recruitment
and optimize their V/Q matching.
When we determine that the patient needs to be intubated, we provide sedation.
We provide neuromuscular blockade, we lie the patients flat,
and they derecruit.
So the heavy, foggy lungs will collapse upon themselves,
causing derecruitment and causing profound hypoxemia.
All of this is further exacerbated by the fact
that we have challenges in pre-oxygenating these patients
as we would other patients.
We know that flush flow oxygen is an excellent way to pre-oxygenate patients
who need to be intubated.
However, the concerns about aerosolization remain.
Similarly, bagging the patients or using non-invasive ventilation
have the same concerns.
So we're intubating these patients with an alteration
in our usual pre-oxygenation strategies, leading to profound hypoxemia.
You can see this derecruitment in their images, as indicated here.
Typically, for most patients, we would use a PEEP valve right
after intubation.
A PEEP valve is a device that fits on the exhalation port of a bag
and has an adjustable valve.
That allows the clinician to provide 5 to about 20 centimeters
of water pressure for the positive end-expiratory pressure.
it works very well to recruit these patients.
However, again because of the concerns with aerosolization,
we are now moving away from using PEEP valves
and using bagging after intubating a patient.
And moving directly to putting the patient straight on the ventilator.
The downsides of doing this are that we don't
recruit the patients as aggressively.
Part of that is that when we bag patients,
we are giving them often higher tidal volumes and higher pressure
ventilation-- at least temporarily--
to recruit them up.
So it works well, but it may be lung injurious.
Placing the patient directly on the ventilator is slower, more gradual.
But it allows us to monitor the pressures.
The real advantage though is that it reduces
the numbers of breaks in the circuit.
Regardless of which method you use to recruit
the patients after you intubate them, a HEPA filter is absolutely mandatory
to maximize the protection of everyone in the room.
The HEPA filter needs to be placed between the patient
and the bag or the ventilator.
I would note in this picture that we have here,
it would actually be more optimal to have the HEPA
filter below end title CO2 detector, instead of how it's portrayed here.
Having the HEPA filter next to the endotracheal tube
would minimize the number of disruptions that are needed to open up the system.
When we ventilate these patients, it's the same concepts
that we use for any other patient with ARDS.
We want to have a low tidal volume ventilation strategy,
targeting between 4 and 8 milliliters of predicted body weight, starting with 6
and titrating from there.
We want to keep the patient on low pressures,
targeting a plateau pressure of less than 30 centimeters of water.
They do seem to be fairly PEEP responsive, so most recommend
starting with a PEEP of 8--
or higher, as needed.
And we want to titrate down their FiO2 as we're able to.
We should be targeting a saturation of 90% to 95% in these patients.
Again, when we are optimizing their ventilation
but they are desynchronous with the ventilator,
we can reach for neuromuscular blockade.
We no longer routinely recommend using neuromuscular blockade
for all patients with ARDS, but it can be beneficial
when a patient remains desynchronous.
If a patient is otherwise optimized and remains hypoxemic,
we can try a gentle recruitment maneuver.
A recruit maneuver seems to be particularly useful in these patients.
Most of these patients have reasonable compliance
and are able to be recruited with improvements in their oxygenation.
We provide gentle, sustained increases in pressure
to reopen the atelectatic areas and increase the surface
area for gas exchange.
We recommend a titrated PEEP strategy using gentle PEEP increases,
rather than a more abrupt increase in the PEEPs.
For more details, please refer to the written materials regarding recruitment
maneuvers and a best PEEP trial.
These patients do seem to respond very well to proning.
Due in part to the significant derecruitment component,
proning a patient when they have a P to F ratio of less than 150
seems to be an appropriate approach.
These patients can do well with proning.
I would note, however, that proning is not
something that should be undertaken by a couple of individuals at a time.
It needs to be a system-based approach.
You have to have buy-in from nurses, your respiratory therapist,
your technicians.
Everyone has to be participating to do this safely.
Inhaled pulmonary vasodilators likely have a role in patients with COVID-19.
I would note, however, that we do not recommend using epoprostenol.
Epoprostenol is very effective as an inhaled pulmonary vasodilator.
The issue is that it's relatively sticky,
and this mandates frequent ventilator circuit changes.
As we don't want to open the ventilator circuits any more than
we absolutely have to-- to minimize the risk of aerosolization--
we want to use nitric oxide if the patient requires any sort
of inhaled pulmonary vasodilator.
I would emphasize again that pulmonary vasodilators have never
been shown to improve outcomes of mortality or ventilator days
or other clinical outcomes in patients with ARDS.
They do improve oxygenation.
And therefore, as part of a multi-modal strategy,
especially if they're being used as a bridge to other therapies,
they can have an important role.
We're noting that patients with COVID-19 are difficult to wean.
Many reports are saying that these patients have prolonged ventilation
times, up to a median of 14 days.
What we find is that when we change patients over to pressure support,
even if they had been looking well on an assist control mode,
they often derecruit and deteriorate precipitously,
mandating that they go back onto volume control.
As this pandemic progresses and we learn more,
I believe that we will have a better understanding of how
we can wean these patients and how we can
determine who is ready to move on to the next stage in their care.
Additional therapies include antibiotics.
We know that bacterial co-infections are very common in patients
with viral pneumonias.
Please provide the patients with broad-spectrum antibiotics.
Steroids are not routinely recommended in these patients.
There may be a subset of patients who would benefit
from steroid administration, but we have yet
to determine who those patients would be.
And so, therefore, they are not recommended at this time.
A dry lung strategy is very appropriate.
We know from other patients with ARDS in critical illness,
that use of diuretics, keeping the patient as dry as possible
can be beneficial to reducing ventilator days and improving outcomes.
This seems to be particularly true in patients with COVID-19.
The role of other medical therapies is also still being determined.
Hydroxychloroquine is very much in the news right now,
but the appropriate use has yet to be determined.
Similarly, we are unsure what the role of statins will be.
Although it does seem that they may have an anti-inflammatory role.
Our recommendation would be to talk with your local infectious disease experts
about the appropriate use of these medications.
Remdesivir being investigated in clinical trials
and should not be used outside of these trials.
There are reports that CT scans are useful in determining
who has COVID-19, with some stating that they have an 80% sensitivity.
This may be true, as the ground-glass opacities
do seem to be a fairly common finding.
However, performing a CT scan is unlikely to change
the management of these patients.
And it does have attendant risks.
First, you have to travel with the patient, take them to the CT scanner.
Second, you have to potentially expose multiple health care
workers, also risking disconnection from the ventilator circuits, and so on.
As such, at our institution, we have actually
stopped doing CT scans on these patients,
unless we are looking for some other pathology,
beyond determining if it's COVID-19.
Many other things that we do in the Intensive Care Unit
are also not appropriate for patients with COVID-19.
Routine chest x-rays as a daily chest x-ray really has no role here.
You're exposing potential health care workers
to the patient for really no benefit.
We follow the patients clinically.
Not with their chest x-ray.
Similarly, bronchoscopy probably has very little role.
There are patients who have a significant secretion burden.
But most of those can be managed by suction, rather than bronchoscopy.
I would note that if you're going to suction the patient, that it
should be done as an inline suction.
And everyone in the room should be wearing N95 masks and aware
that this is happening to prevent aerosolization and possible
contamination.
As this pandemic continues, we will learn more
about how to best take care of these patients.
Right now, there are many controversies and many questions unanswered.