12. Undifferentiated Shock Roundtable

Posted on March 29, 2022 by Pulm PEEPs

This week the Pulm PEEPs, David Furfaro and Kristina Montemayor, are joined by three outstanding critical care doctors and medical educators to discuss the evaluation of patients with undifferentiated shock. We cover everything from the basics about defining shock, to advanced POCUS techniques to clarify the etiology of shock. Listen today and let us know your favorite technique for evaluating shock in the ICU.

Meet Our Guests

Molly Hayes is an Assistant Professor of Medicine at Beth Israel Deaconess Medical Center and Harvard Medical School, the Director of the MICU at BIDMC, and the Director of External Education at the Carl J Shapiro Institute for Education and Research. She is also a course director for a yearly CME course on principles of critical care medicine run by BIDMC and HMS.

Nick Mark is a Pulmonologist and Intensivist at Swedish Medical Center in Seattle, Washington. He is also the founder of ICU One Pager, which produces high yield critical care education one-page guides that have been downloaded by thousands of learners.

Matt Siuba is an Assistant Professor of Medicine and intensivist at the Cleveland Clinic, where he is the associate program director for the Critical Care Medicine fellowship. He founded and runs the website Zentensivist.com, has his own associated podcast, and is a senior editor at CriticalCareNow.com.

Key Learning Points

Key graphics

Definition of shock

– Shock is defined as inadequate oxygen delivery to meet the body’s needs. Decreased perfusion and oxygen delivery leads to cell injury and death

– If you define just as hypotension, you will miss people who have cryptic shock, and categorize some people with shock who don’t have it

– Cryptic shock = a patient with normal blood pressure (MAP > 65), but who still has shock based on inadequate O₂ delivery

– O₂ delivery is broken down in to cardiac output and arterial oxygen content

Causes of shock

Shock can be divided into three large categories:

1) A pump problem – low cardiac output. This includes cardiogenic and obstructive shock. Make sure to remember to look for tamponade and valvulopathies.

2) A pipe problem – low systemic vascular resistance. This includes distributive shock. Distributive shock is most often due to sepsis but can be due to anaphylaxis, endocrinopathies, cirrhosis, or spinal shock.

3) A tank problem – low preload. This includes hypovolemic and hemorrhagic shock. Make sure to remember about high intrathoracic pressure, which can decrease effective preload.

Examining a patient with undifferentiated shock

– See if the patient is on the “Shock BUS” by examining their brain (mental status), urine output, and skin

– Feel if their skin is warm vs cold and if it is mottled

– Feel the patient’s pulses to see if they are bounding, normal, or thready

Point of Care Ultrasound

– “Ultrasound is the new stethoscope”

– The first step is to always look at the heart and look for chamber size and function. You can then look for pericardial effusion

– Point of care ultrasound then includes looking at the lungs for signs of fluid overload, consolidation, or pneumothorax

– A complete ultrasound also involves looking at the abdomen and at the extremities for DVT

– More specific ultrasound techniques include looking at:

1) IVC exam to estimate right atrial pressure. This test is often misused. It is most helpful in states when the patient has low stroke volume and trying to figure out if they have cardiac limitation to stroke volume vs if they are hypovolemic.

2) Velocity time index as a measure of cardiac output to trend with interventions

References and links for further reading

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Radiology Rounds – 3/8/22

Posted on March 8, 2022 by Pulm PEEPs

We’re excited to bring you another Radiology Rounds today that combines pulmonary and critical care.

The patient is diagnosed with small cell lung cancer and requires a left bronchial stent. She develops acute hypoxemic and hypercapnic respiratory failure requiring intubation.

You are concerned that she has increased airway resistance as a result of stent migration. What would you expect to see on the ventilator if this is the case?

Here are some tips from ICU OnePager on interpreting high peak pressures on the ventilator

6. PEEP in ARDS Roundtable

Posted on January 4, 2022 by Pulm PEEPs

This week on Pulm PEEPs, Dave Furfaro and Kristina Montemayor are joined by experts in the field of critical care medicine and ARDS to discuss all things PEEP! Drs. Roy Brower, Sarina Sahetya, Todd Rice, and Elias Baedorf-Kassis discuss everything ranging from PEEP basics to their approach to optimizing PEEP in patients with ARDS.

Meet Our Guests

Roy Brower is a Professor of Medicine at Johns Hopkins where he served as the MICU director for over 33 years, and he has been one of the pioneers for lung-protective ventilation for patients with ARDS.

Elias Baedorf-Kassis is an Assistant Professor of Medicine at Beth Israel Deaconess Medical Center and Harvard Medical School. He is the Medical Director of Respiratory Care at BIDMC, and helps lead the VV-ECMO program.

Todd Rice is an Associate Profess of Medicine in the Division of Allergy, Pulmonary, and Critical Care Medicine at Vanderbilt University and Vice President for Clinical Trial Innovation and Operations in the Vanderbilt Institute for Clinical and Translational Research.

Sarina Sahetya is an Assistant Professor of Medicine at Johns Hopkins Hospital and does research in the diagnosis and treatment of ARDS.

Key Learning Points

Driving Pressure figure from Amato et al. 2015. Stress index figure from Hess 2014.

The plateau pressure can be measured on the ventilator with an inspiratory hold maneuver
Extrinsic PEEP is applied by the ventiilator, while intrinsic PEEP, or auto-PEEP, occurs when there is incomplete emptying of the lungs due to inadequate time for exhalation. This often happens with obstructive lung disease. Intrinsic PEEP can be measured on the ventilator with an end-expiratory hold maneuver
We utilize PEEP in all intubated patients to minimize atelectasis. When patients are supine, the heart moves back 2 cm and the diaphragm raises by 2 cm, so often the left lower lobe of the lung is compressed and there is atelectasis there. This is often seen on CXR:

References, Image Sources, and Further Reading

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Radiology Rounds – 12/28/21

Posted on December 28, 2021 by Pulm PEEPs

Today we’re bringing you a special edition of Radiology Rounds complete with classic imaging, and some key critical care and ventilator physiology. This case is a perfect lead-in for next week’s Pulm PEEPs Roundtable on PEEP titration, so make sure to tune in!

How would you best describe the imaging findings?

There are bilateral, diffuse alveolar infiltrates noted on imaging with evidence of an air bronchogram on the CT image.

The patient develops worsening hypoxemia requiring mechanical intubation. The patient has multifocal pneumonia and requires intubation. ABG is performed and the calculated PaO2:FIO2 ratio is 150. How would you describe the severity of ARDS?

This patient has moderate ARDS based on a PaO2:FIO2 ratio that is between 100 and 200. The patient’s initial ventilator settings on volume control are:

Based on these parameters, we can also calculate the driving pressure. Driving pressure is calculated by using Pplat-PEEP. In this case, Pplat (30)-PEEP (10), would give a driving pressure of 20.

4. Top Consults: Hemoptysis

Posted on December 7, 2021 by Pulm PEEPs

Pulm PEEPs hosts, Kristina Montemayor and David Furfaro, bring our first episode in our Top Consults series. In this series, we will bring in experts to work through the most common pulmonary and critical care consults. Whether you are the consulting physician, or a pulmonologist responding to the page, these episodes are geared to give you all the information you need to care for your patients!

Today, we are joined by Chris Kapp and Matthew Schimmel, two interventional pulmonologists, to discuss hemoptysis. Chris and Matt will help us work through two hemoptysis consults, and together we’ll provide a framework for thinking about hemoptysis, outline some key components of the evaluation, and delve into treatment options.

Key Learning Points

Hemoptysis Evaluation

Hemoptysis Management

Life-Threatening or Large Volume Hemoptysis

Stabilize the patient! Make sure the airway is protected either by the patient coughing themselves, or intubation if needed. Provide hemodynamic support with IVF, blood products, and pressors if needed. If it is known which lung has the bleeding the patient can be positioned so the lung with the bleeding is down. This protects the non-bleeding lung.
Correct any bleeding diathesis If the patient is on anti-coagulation, or has any reversible bleeding diathesis, these should be corrected immediately to reduce further bleeding.
Localize the bleed If the patient is stable, they should undergo a CTA to localize the bleeding. If they are not stable to make it to a CT scan, a bronchoscopy should be performed.
Bronchoscopic treatment In addition to clearing blood from the airway, bronchoscopy can localize the bleeding. With available expertise, bronchoscopic treatments can be performed such as ice saline, topical epinephrine, or balloon tamponade to isolate the bleed.
Definitive therapy with arteriography and embolization Patients with life-threatening hemoptysis should ultimately undergo arteriography and embolization of any bleeding vessel. If this is not possible, then surgery can be needed in some cases.
A note on diffuse hemoptysis If there is not one distinct bleeding lesion, then localizing and treating the bleed becomes more difficult. For diffuse alveolar hemorrhage, evaluation should be performed for if it is primary, and due to an immunologic cause and capillaritis, or secondary to a systemic disease and / or bleeding diathesis. These investigations will guide available treatment options. Capillaritis from an immunologic cause, such as lupus or vasculitis, can be treated with systemic glucocorticoids and an additional immunosuppressive agent such as cyclophosphamide or rituximab.

Non-life-threatening or Small Volume Hemoptysis

Monitor for clinical worsening Patient’s should be monitored, either in the in-patient or out-patient setting, for increased volume or frequency of hemoptysis and for any clinical worsening, such as desaturations or decreased ability to clear the airway.
Correct any bleeding diathesis If the patient is on anti-coagulation, or has any reversible bleeding diathesis, these should be corrected immediately to reduce further bleeding. In pattients with non-life-threateneing hemoptysis this requires careful consideration of balancing the risk of bleeding vs the benefits for continuing anti-coagulation.
Evaluate for underlying cause Patient’s should undergo imaging and evaluation for the underlying cause of the hemoptysis. This may be evidence of an underlying infection, a pulmonary embolism, or new lung lesions making the patient at risk. If the source can’t be found on non-invasive imaging, and there is no clear systemic source such as an infection, a bronchoscopy is warranted. Any underlying cause should be treated and investigated further.
Inhaled Tranexamic Acid Nebulized tranexamic acid is well tolerated and can help resolve hemopytysis without invasive procedures.

References and links for further reading