Respiratory distress: An emergency medicine approach

Case

A 58 year old woman is brought in by EMS with acute onset respiratory distress. Over the last few hours, she has found it increasingly difficult to breathe. On arrival, she is diaphoretic and using accessory muscles. She is quite tachypneic at a rate of 45 breaths a minute, and her oxygen saturation is 82%. How do you approach a patient with undifferentiated respiratory distress?

My approach to respiratory distress

My “first 10 minute” approach to a sick patient with undifferentiated difficulty breathing is focused on rapidly finding the right therapy, but not necessarily on finding the right diagnosis. I find that this simplifies my thinking. There are only a limited number of things that I can do to help a patient with dyspnea and I want to quickly pick the best therapies from my menu:

• Airway management
• Oxygen (including high flow humidified nasal oxygen)
• Positive end expiratory pressure
• Positive pressure ventilation
• Chest decompression
• Bronchodilators (and steroids eventually)
• Epinephrine
• Nitroglycerin
• Cardioversion
• Thrombolytics / PCI
• Pericardiocentesis

In real life, many of these interventions are proceeding in parallel, especially if you are working in a larger institution. The linear nature of the blog post is not meant to imply that you must proceed through the steps in the order presented. However, they are laid out in what I consider the order of priority, and I think running through the same ordered checklist in my mind with each patient helps ensure I don’t miss something important. (Note: this approach assumes aggressive life-saving interventions are appropriate. For an approach to palliative dyspnea, see this post.)

Position the patient

Almost all dyspneic patients will be better in the sitting position. Raise the head of the bed, or allow the patient to assume their own position of maximal comfort. 

Is the airway patent?

The airway assessment should be very rapid. Can the patient speak? Is the patient alert? Is there stridor or gurgling? Is there respiratory effort without any air movement? Look in the mouth and feel the anterior neck.

If I am concerned about airway, I start with basic airway maneuvers. If the basic airway maneuvers aren’t enough, the patient will require intubation, but it is important to ask: is this patient ready for an RSI?

Respiratory assessment: oxygen saturation and work of breathing

Oxygenation and ventilation are two separate processes, and it can be helpful to consider them separately. However, in the first few minutes I consider them together. (It doesn’t make any sense to put on an oxygen mask to address a low saturation, and then remove it moments later because noninvasive ventilation is required for respiratory distress.)

What is the oxygen saturation?

All things considered, I think the oxygen saturation probe is the most valuable tool we have available. If I was alone, managing the patient in sequential steps, my next move is to grab the oxygen saturation probe.

If the patient is hypoxic, provide oxygen. (I usually start with a combination of nasal prongs at 15 L/min and a nonrebreather set at flush rate, and titrate down later). I will also apply oxygen if I think there is a chance of early intubation. However, routinely providing high flow oxygen to patients who are not hypoxic removes an important monitor of the patient’s status, and has been shown to be harmful in multiple trials, so I avoid oxygen therapy if it is not required. (Girardis 2016; Chu 2018)

Persistent hypoxia despite face mask oxygen is likely a sign of shunt physiology or an alveolar diffusion problem (assuming you have ruled out airway obstruction and apnea). This is treated with PEEP (positive end expiratory pressure), which can be accomplished either by holding a good 2 hand seal on a bag valve mask that has a PEEP valve attached, by starting CPAP, or by intubating and providing PEEP with the ventilator.

Is the patient moving enough air?

Take a moment to look at the respiratory rate, tidal volume, and work of breathing. Apnea requires bag valve mask ventilation and empiric naloxone. Treat poor ventilatory effort with BPAP or assisted breathing with a bag valve mask. Similarly, if the tidal volume is adequate, but the patient is working very hard to achieve those tidal volumes, non-invasive positive pressure ventilation is warranted, as the patient will predictably tire.

If agitation (often the result of dyspnea, hypoxia, or hypercarbia) is preventing the adequate delivery of face mask oxygen or noninvasive ventilation, small boluses of ketamine can be used for sedation. (This is known as delayed sequence intubation). (Weingart 2015)

What are the rest of the vital signs?

To round out the rest of the basics, get the patient on the monitor, get a full set of vital signs, and have a team member start working on vascular access. Obvious life threats, such as cardiac arrhythmias, shock, or apnea, should be addressed before moving on.

Directed history and physical to guide initial empiric therapy

Perform a quick exam. In addition to the airway assessment above, I focus on breath sounds, breathing pattern, heart sounds, and a skin exam. In general, I find history is more valuable than physical exam, although it is frequently impossible to gather history from a patient with significant dyspnea. (If the patient can’t speak, don’t worry about the history. Just get empiric therapy started, and move on to your adjuncts like ultrasound.) Don’t forget that you can also gather history from other sources, such as family, friends, EMS, and the chart. In the early moments, I will often assign a team member to gather this information for me.

Start empiric therapies based on the clues. At this point, the goal is starting treatment rather than making a definitive diagnosis. The initial diagnosis and empiric therapy may turn out to be wrong, but that is OK. For example, even though I know that CHF can present with wheeze, in the initial minutes I am quite comfortable treating all wheezing patients with salbutamol. The key is not getting anchored and changing treatment strategies as more information becomes available.

• Wheeze → salbutamol, ipratropium, steroids
• Crackles with a normal or high blood pressure → nitroglycerin and CPAP
• Unilateral decreased breath sounds → finger thoracostomy (usually, but not always, after confirmation with an ultrasound or x-ray)
• Hives → Intramuscular epinephrine

Add bedside diagnostic tests

While waiting for the initial empiric therapy to work, there are three diagnostic tests that almost every dyspneic patient will get: an ECG, a chest xray, and a bedside ultrasound. Get an early ECG to rule out STEMI and arrhythmias. A portable chest x ray is also valuable (although with the advent of bedside ultrasound it may be less important.)

Point of care ultrasound is incredibly helpful in the management of dyspneic patients. There are a number of algorithms available. I start with a rapid lung ultrasound to rule out pneumothorax and large pleural effusion. In doing so, I am looking at multiple locations on both sides of the chest, so I get the general sense whether there are diffuse B lines, A lines, or more focal disease (that I might come back to reexamine later). Next I look at the heart, first to rule out a pericardial effusion, then to get a sense of the left heart function, and finally to look at the size of the right ventricle. In the first few minutes, I am mostly looking for gross abnormalities. As the resuscitation settles, I will spend more time to reassess any abnormalities noted, and to perform a more thorough scan if the diagnosis remains unclear. (For a more in depth post on ultrasound in dyspnea, check out the POCUS Atlas).

Reassess

It is rare to have a definitive diagnosis for dyspneic patient in the initial minutes in the resuscitation room. Empiric therapy is often started without a diagnosis. They key is reassessment, both to determine ongoing treatment and to hone in on the correct diagnosis.

In fact, I would argue that reassessment plays a central role in all resuscitation. If you haven’t heard Scott Weingart talk about OODA loops, I strongly suggest doing so.

Determine definitive testing and plan disposition

If the diagnosis remains unclear despite gathering a more thorough history, performing a complete ultrasound, and watching the response to empiric therapy, it is time to consider further diagnostic tests. Blood work will likely have been sent automatically. CT is helpful if pulmonary embolism is being considered, as well as in the diagnosis of atypical infections, inflammatory conditions, and neoplasms. An urgent formal echocardiogram may be required, especially in the context of a murmur where an acute valvular disorder is suspected.

Contact the ICU or appropriate admitting team, or work on getting the patient transferred if necessary.

Review a checklist

Finally, after the initial interventions are done and empiric therapies started, I will review a checklist to help ensure I am not missing an important diagnosis.

• Dyspnea
  • Upper airway
    • Forgein body
    • Blood or vomit
    • Allergy
    • Trauma
    • Mass
    • Laryngospasm
    • Epiglottitis / other infectious
  • Lungs
    • Pneumothorax
    • Pneumonia
    • PE
    • Bronchospasm (asthma, COPD, anaphylaxis)
    • Pulmonary effusion
    • Other (fibrosis, neoplasms)
  • Heart
    • MI
    • Tamponade
    • Acute pulmonary edema
    • Arrhythmia (bradycardia or tachycardia)
    • Valvular disease
    • Other (myocarditis, cardiomyopathy, congenital disease)
  • Apnea
    • Not really “distress”, but still common cause of hypoxemia/hypercapnia
    • Drugs (opioids)
    • Neurologic disasters
    • Hypoglycemia
  • Other
    • Acidosis (DKA/ ASA overdose)
    • Carbon monoxide
    • Methemoglobinemia
    • Anemia
    • Neuromuscular weakness (Guillain Barre syndrome, myasthenic crisis)
    • Chest wall (obesity, burns)
    • Abdominal pressure (ascites, abdominal compartment syndrome)
    • Anxiety

Notes

Many thanks to Drs. Salim Rezaie, Anand Swaminathan, and Anton Helman for their peer review and feedback on this post.

Other FOAMed Resources

Critical Care Fundamentals: Approach to Acute Respiratory Failure on REBEL EM:

Critical Care Fundamentals: Approach to Acute Respiratory Failure

Taming the SRU: Take My Breath Away! Evaluation of Shortness of Breath in the ED

POCUS Atlas: POCUS for Undifferentiated Shortness of Breath

CRACKCast E025 – Dyspnea

FlippedEM classroom: Approach to shortness of breath

RCEM learning: Breathlessness

References

Chu DK et al. Mortality and morbidity in acutely ill adults treated with liberal versus conservative oxygen therapy (IOTA): a systematic review and meta-analysis. The Lancet 2018.

Girardis M et al. Effect of Conservative vs Conventional Oxygen Therapy on Mortality Among Patients in an Intensive Care Unit: The Oxygen-ICU Randomized Clinical Trial. JAMA 2016; 316(15): 1583 – 1589. PMID: 27706466

Petousi N. Acute respiratory failure. In: Sprigings D, Chambers J (eds). Acute Medicine ‐ A Practical Guide to the Management of Medical Emergencies, 5th Edition. John Wiley & Sons; 2018.

Sprigings D, Chambers J. Acute breathlessness. In: Sprigings D, Chambers J (eds). Acute Medicine ‐ A Practical Guide to the Management of Medical Emergencies, 5th Edition. John Wiley & Sons; 2018.

Weingart SD, Trueger NS, Wong N, Scofi J, Singh N, Rudolph SS. Delayed Sequence Intubation: A Prospective Observational Study Annals of Emergency Medicine. 2015; 65(4):349-355.