COVID-19has brought unprecedented challenges regarding the ability to generate timely evidence, all while this pandemic overwhelms hospitals and health care workers.
About 5% of patients with COVID-19 require admission to the intensive care unit and mechanical ventilation.
Based on the recent epidemiological models, COVID-19 is going to hit all the areas in this country. So the surge is coming, and not just to the hotspots like NYC.
With every ICU in this country preparing for the surge, there are a number of changes that intensive care units are making, including ours.
We are preparing anesthesiologists (who are not CCM trained) and nurse anesthetists, to help us manage patients with COVID-19. Even though they are not CCM trained, we have a lot of overlap of knowledge, especially when it comes to managing ventilators, and we have a lot of overlap with certain procedures.
By allowing anesthesiologists and nurse anesthetists to help in this manner, it will help other intensivists like myself handle the surge of patients coming our way.
And because they are helping us, that is the main reason for me making this video, so that they can watch this and be better equipped to handle the surge with us. And this video is intended for any health care provider out there who has the potential to care for critically ill patients with COVID-19.
So pass this along if you know someone in the same boat as you. And if you are not a health care worker, most of the info in this video will probably be too technical for you to understand, but feel free to watch anyway.
So in this video, I am going to cover the most important aspects of caring for a critically ill patient with COVID-19, and how to manage different scenarios.
The info in this video is based on several things:
1) what we know so far about COVID-19 (mainly from studies in China)
2) standard care for critical care patients in general
3) my experience, and the experience of many of my colleagues, of caring for critically ill patients
Knowing, and implementing all of the info inthis video does not guarantee you save a COVID-19 patients life in the ICU, but, it will give you the best chance of doing so.
Solets get to it.
If a patient with COVID-19 is coming to your ICU, they most certainly have pneumonia, and they probably have acute respiratory distress syndrome (ARDS) as well. They may or may not be in shock, which often happens in patients with ARDS, and in patients with sepsis.
Patients with severe disease who require ICU admission are likely to have high oxygen requirements.
Although both High flow oxygen and noninvasive positive pressure ventilation have been used for COVID, the safety of these is uncertain, and they are consideredaerosol-generating procedures that warrant specific isolation precautions. The same goes for nebulized treatments, such as duonebs.
Most patients who require ICU admission have ARDS, and they will likely have a better outcome if intubated sooner rather than later. That is another reason why it likely better to skip Hi-Flow oxygen and NIPPV, and jump straight to intubation.
COVID-19 patients often have rapid clinical deterioration, and there needs to be a low threshold to intubate once their oxygen requirements start climbing.
Acute Respiratory Distress Syndrome (ARDS)
ARDS is a clinical diagnosis, based on non-cardiogenic pulmonary edema, with bilateral patchy infiltrates on chest imaging, and a PaO2/FiO2 ratio of less than 300.
In ARDS, there is this crazy, chaotic inflammatory response within the lungs, with damage to the alveoli and surrounding capillaries, which leads to excess protein and fluid accumulation in interstitial and alveolar spaces.
That means decreased lung compliance, increased V̇/Q̇ mismatch, and increases in shunt and dead-space ventilation.
Patients with ARDS are at high risk of mortality, which increases with ARDS severity. With that said, mortality is usually the result of the underlying disease that triggered ARDS, rather than refractory hypoxemia.
The severity of ARDS is important, because its going to determine how we manage patients with ARDS.
And severity is determined by the PaO2/FiO2 ratio.
Mild ARDS is a PaO2/FiO2 ratio between 200 – 300.
Moderate is a ratio of 100 – 200
And Severe is less than 100.
With ARDS, the alveoli fill up with protein and fluid. This leads to at least partial alveolar collapse, and decreased lung compliance, with shunt physiology.
This is why having a high PEEP is crucial, meaning, a high positive end-expiratory pressure.
Increasing the PEEP minimizes the repeated opening and closing of distal airways and alveoli. It also improves the homogeneity of the lung parenchyma by reducing drastic differences in regional lung compliance.
It also improves V̇/Q̇ mismatch and shunt by maintaining alveolar recruitment. You’re essentially “popping open” as many collapsed alveoli as possible.
What is the ideal level of PEEP?
No one knows for sure.
Typically for ARDS, we to set the initial PEEP between 10 to 15. Sometimes all the way to 20 if they have severe disease. You don’t want to go too high though, because this increases the risk of pneumothorax.
Here is a table from the ARDSnet trial that has gives a suggested PEEP and FiO2 strategy. Just remember that in general, the more severe the ARDS, the higher PEEP you’re going to want to use:
So increasing the PEEP pops open alveoli and improves oxygenation. And that’s great.
Using low tidal volumes is the other key to managing ARDS patients, as this has been shown to improve mortality.
Current ARDS goals include both a tidal volume of ~6 mL/kg of predicted body weight and maintenance of the lowest possible plateau pressure.
Typically, this comes out to tidal volumes in the 300’s for women of average height, and tidal volumes in the 400’s for men of average height.
But giving a patient low lung volumesis not typically comfortable for the patient, so its important to properly sedate patients in order to accomplish our lung-protective strategy of low-lung volume ventilation.
And because of this, they are going to develop a respiratory acidosis. Its called permissive hypercapnia. That’s the sacrifice we make in order to achieve our ultimate goal, which is survival.
Now let’s talk about some other things you can do for patients with ARDS.
Recently, the PROSEVA trial demonstrated improved mortality in ARDS patients with a PaO2/FiO2 ratio of less than 150 who were treated with early prone positioning and LTVV.
Why is prone positioning beneficial?
When we lay in a prone position, the weight of the heart no longer compresses the posterior lung regions, and this allows for improved V̇/Q̇ matching. Also, with positive pressure ventilation, the diaphragm moves more freely in the prone position, which means better chest wall compliance, and better gas exchange in the lower lung fields.
To get the maximum benefit, proning should be done for 16 hours a day.
APRV – Other methods to optimize ventilator management in ARDS have been suggested, including inverse ratio ventilation, and high-frequency oscillator ventilation (HFOV). None of these have demonstrated mortality benefit in ARDS in adults.
Corticosteroids, such as Methylprednisolone (solumedrol), if given EARLY, for SEVERE ARDS, may improve ICU length of stay and number of days on mechanical ventilation. These studies were based on ARDS patients before COVID-19 came about.
The idea here is that steroids suppress the inflammation that occurs in the beginning phase of ARDS.
There was recently a retrospective, non–peer-reviewed report of 46 COVID-19 patients who had severe pneumonia. And 26 of those patients were treated with methylprednisolone, 1 to 2 mg/kg/d for 5 to 7 days, which was associated with a reduction in duration of fever and the need for supplemental oxygen.
So as of right now, the recommendation is give COVID-19 patients steroids only if they have ARDS.
Neuromuscular blockade, such as with cisatracurium (Nimbex), is sometimes used for severe, refractory, or life-threatening hypoxemia, especially if there is severe ventilator dyssynchrony.
There is not enough evidence to definitively say that there is a mortality benefit of using paralytics. And the downside to using them is that there is the potential for critical-illness myopathy and neuropathy, so only use neuromuscular blockade if absolutely needed.
Inhaled nitric oxide (NO) is a pulmonary vasodilator, but is not routinely done for adults with ARDS because, although it usually improves oxygenation, it has not been shown to reduce morbidity or mortality. But if you are maxed out on your vent settings, and the patient is still hypoxemic, it’s worth a try.
Critically ill patients with COVID-19 often develop septic (distributive) shock. And for shock, we give IVF and vasopressors. But ARDS patients generally do better when you keep them in a negative fluid balance state. So if you have a COVID-19 patient who is in shock and ARDS, what should you do?
Based on my experience of treating ARDS patients who are in shock, my recommendation would be to use minimal fluid possible, and to start vasopressors early. In my experience, patients tend to respond better to albumin than crystalloids, especially if they have low albumin levels. Either way, you’re going to want to assess fluid resuscitationresponsiveness, and if they don’t respond well to fluids, just stick with the vasopressors.
1st line vasopressor is always going to be norepinephrine, aka levophed, with 2nd line being vasopressin, especially if they’re tachycardic.
Central line – do you really need to put a central line in? not only does inserting a central line expose more health care workers to the virus, but it also entails using more PPE. So hopefully patients don’t need a central line. Sometimes you can run a pressor, through a peripheral IV.
You can get away with doing so if:
1) your PIV is relatively large guage
2)your peripheral is not extremely distal, so if you have an AC PIV or midline, and
3) its you are running only one pressor at a low dose. So for example, you have levophedrunning at less than 10 mcg (arbitrarily 10 mcg)
If you cant meet these criteria, or if you require multiple infusions, then you will likely need a central line.
In critically ill adults with fever, use of medications for temperature control is sometimes needed. The biggest concern of having fever in the ICU is the potential to worsen tachycardias and tachyarrhythmias. If the fever is only mild, or tachycardia is not a concern, then treatment is less warranted.
But if you need to treat it, acetaminophen is the go-to drug, unless they are in liver failure. Just remember to aim for less than 3 g per day, and even lower if they have a liver injury.
Even before COVID-19 came around, NSAIDs such as ibuprofen are rarely given to ICU patients, because these drugs have lots of potential for side effects, including acute kidney injury, gastritis, peptic ulcer disease, and more. ICU patients are already at higher risk for getting acute kidney injury and gastritis, and NSAIDs only add to that risk.
There are some investigational agents out there, they may or may not help COVID-19 patients. But routine use of standard IV immunoglobulin, for example, is not suggested. The same goes for convalescent plasma is also not suggested. And there is insufficient evidence right now to recommend using antiviral agents such as remdesivir, recombinant interferons, chloroquine/hydroxychloroquine, or tocilizumab.
Extracorporeal membrane oxygenation (ECMO) is a type of prolonged mechanical cardiopulmonary support that is usually delivered in the intensive care unit, and is only be performed in centers with the appropriate equipment and expertise. There are about 250 hospitals in this country that can do ECMO.
Its reserved for patients with severe, but potentially reversible, acute respiratory or cardiac failure that is unresponsive to conventional management.
There are two types of ECMO, venovenous (VV) and venoarterial (VA).
VV ECMO is used in patients with respiratory failure, while VA ECMO is used in patients with cardiac failure.
Bleeding is the most common complication (35%) of ECMO. Thromboembolism and cannula complications occur in less than 5%.
I can tell you right now, that if a COVID-19 patient needs ECMO, it’s going to be very difficult for that patient to get ECMO because very few patients meet the criteria. And if they do meet the criteria they have to be at a hospital that does ECMO. And there are very few hospitals right now, if any, that are willing to accept a COVID patient from another hospital to do ECMO. Maybe this will change when the pandemic slows down.
Code Status (DNR vs Full Code)
Normally when a patient comes to the hospital, especially when they come to the ICU, we have a discussion with the patient and/or family regarding their code status. Like, do they want CPR if their heart stops, do they want a breathing tube if they cant breathe on their own, etc. And ultimately, the family and/or patient decides on whether or not they will be DNI/DNR or not.
However, the surge of COVID-19 patients is changing that decision-making process in some places. Some places have a team that decides which patients will be DNR or not. This is happening simply because resources are limited, mainly ventilators.
Dr. Mike Hansen, MD
Internal Medicine | Pulmonary Disease | Critical Care Medicine
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