Respiratory Distress

by Ebru Unal Akoglu

Case Presentation

A 40-year-old female with a history of diabetes mellitus presents with a complaint of 6 days cough and muscle aches. Patient has right-sided chest pain with deep breathing. Her vitals are the following: temperature 37.1 degrees Celcius; blood pressure 150/97 mmHg; heart rate 120 bpm; respiratory rate 19/min; and pulse oximetry 89%. On physical examination, she has diminished breath sounds and ronchi at the right bases. Her chest X-ray is shown in Figure 1.

What are the diagnostic considerations? What is your next move? What is the most appropriate management strategy? Figure 1: Chest X-ray of the patient. (Courtesy of Ebru Unal Akoglu)

In the emergency department, respiratory distress is a challenging chief complaint and diagnosis, and you should evaluate, examine and ease (treat) the patient simultaneously. You have to act quickly with limited information, or your patient can decompensate in front of you.

Objectives of this chapter are listing the causes of respiratory distress, describing the initial approach to a patient with respiratory distress and discussing the initial management plan for a patient with respiratory distress.

Introduction

Respiratory emergencies are common presentations to emergency departments. Appropriate assessment and timely interventions may be crucial in dyspneic patients. Respiratory distress is responsible for nearly 4 million ED visits each year and is one of the most common presenting complaints in the elderly. Management of acute respiratory distress is a challenging task. Good patient outcomes rely on your ability to assess ventilation, oxygenation, work of breathing, lung function, airway resistance and air flow.

When a patient presents with dyspnea, the primary task of the emergency physician is to assess for and ensure the stability of the patient’s airway, breathing, and circulation (ABC).

Respiratory distress is used to describe varying degrees of problems in the respiratory system.

Rapid assessment may necessitate intubation, BiPAP (Bilevel Positive Airway Pressure), nebulizations, decompression or other therapies in the immediate period following the patient’s arrival. Sometimes, it may be hard to decide whether your patient needs medication, suctioning, airway management, intubation, mechanical ventilation support (invasive, non-invasive) or just close observation.

Respiratory distress is a term utilized to summarize a complex of clinical features. These are tachypnea, hypoxemia (peripheral arterial oxygen saturation [SpO2] <90% on room air), increased work of breathing (intercostal, subcostal, or suprasternal retractions; nasal flaring; grunting; use of accessory muscles) apnea, altered mental status, and cyanosis which is characterized by >5gr/dL of deoxygenated hemoglobin.

At this moment, it is better to share some terms and definitions. Please check Table 1.

Healthy lungs are the cornerstone of fluid regulation among the interstitium and alveoli, which can be destroyed by lung injury.

Lung injury can cause abnormal gas exchange, impaired compliance, and pulmonary pressure. Normal lung function requires dry, patent alveoli assisted by proper capillary perfusion and patent endothelium.

Respiratory distress is a consequence of an alveolar injury producing diffuse alveolar damage. Tumor necrosis factor, interleukin (IL)-1, IL-6, and IL-8, are the pro-inflammatory cytokines released after injury and recruit neutrophils to the lungs. Activation of neutrophils causes endothelium damage that ends with impairment of hydrostatic and oncotic forces of membranes.

Damage to the capillary endothelium causes the escape of proteins from intravascular space. The membranous hydrostatic and oncotic forces are lost, and the interstitial space fills with fluid. Also, the clearance ability of the membranes may be lost.

Increase in interstitial fluid, combined with damage to the alveolar epithelium, causes the air spaces to fill with bloody, proteinaceous edema fluid and debris from degenerating cells. Besides, the functional surfactant is lost, resulting in alveolar collapse.

Lung injury has numerous consequences including impairment of gas exchange, decreased lung compliance, and increased pulmonary arterial pressure.

Patients with acute respiratory distress tend to progress through three relatively discrete pathologic stages. These are 1) Exudative stage: diffuse alveolar damage, 2) Proliferative stage: resolution of edema, squamous metaplasia, deposition of collagen, and 3) Fibrotic stage: diffuse fibrosis and cyst formation.

Acute respiratory distress is the clinical consequence of lung injury. Many predisposing factors may lead to lung injury (Table 2). Associated abnormalities increase the risk for adverse outcomes.

Initial Stabilization

The following three assessment questions guide management:
1. Is the airway patent? (A)
2. How adequate is breathing? (B)
3. Is oxygenation sufficient? (C)

Airway

Abnormal breath sounds often point to the obstruction. Snoring indicates obstruction of the airway, usually by the tongue. Simple interventions can lead to marked improvement. For example, head tilt maneuver or a nasopharyngeal/oropharyngeal airway often eliminates snoring. Inspiratory stridor suggests obstruction above the vocal cords (a foreign body obstruction or epiglottitis). Any foreign body should be removed immediately. Expiratory stridor often comes from below the cords (as in croup or a deeper foreign body).

Breathing

Coarse lung sounds, formerly called rhonchi, generally result from secretions in the airway. Nasotracheal suctioning of accumulated secretions using a soft, flexible catheter clears coarse-sounding lungs. Wheezing suggests flow restriction below the level of the trachea, whereas crackles (or rales) indicate the presence of fluid or atelectasis at the alveolar level. Administration of an inhaled bronchodilator significantly reduces wheezing.

The most difficult management part of a patient with respiratory distress is ventilation support. Unfortunately, unrecognized inadequate breathing, failure of ventilator support or unassured airway will ultimately lead to cardiopulmonary arrest. If breathing is inadequate, ventilation must be provided immediately. Ventilation can be non-invasive or invasive.

Non-invasive refers to ventilator support provided through the patient’s upper airway, usually using an oxygen mask, nasal cannula or bag-valve-mask (BVM) depends on the patient’s need.

Invasive refers to ventilator support provided by passing the upper airway with an endotracheal tube, supraglottic airway (e.g., laryngeal mask airway or laryngeal tube) or tracheostomy depending on the need. Unassured airway patency is the most important indication for invasive ventilation.

Circulation

Hypoxia is the lack of sufficient oxygen in the body. Hypoxia may result from an airway patency problem, failure of ventilation support, or an intact airway with good breathing but poor perfusion and oxygenation. In airway management, the first approach is the clearance of airway and positioning; this maneuver often increases oxygen saturation and improves ventilation. If oxygen saturation does not increase, the second approach is oxygen support using an oxygen mask, nasal cannula or bag-valve mask, depending on the patient’s need. If oxygen saturation still does not increase, airway devices should be applied, or the patient should be intubated. The aim is the correction of hypoxia ideally to maintain saturation at 94-98% by titration of oxygen carefully. The treatment depends on the condition that causes respiratory distress. However, in a general approach, CAB+D – circulation, airway, breathing, and drugs is the perfect treatment protocol in the ED.

Some critical actions should be done at every stage if necessary.

C – Circulation: two large bore IV access, fluids if hypotensive, monitorization

A – Airway: oropharyngeal or nasopharyngeal airway devices, LMA, some maneuvers (Head Tilt, Heimlich), suction, medication for an allergic reaction

B – Breathing: Oxygenation (nasal cannula, non-rebreather mask) if not responding, next step is non-invazive mechanical ventilation support or intubation

D – Drugs: Depending on the patient’s primary problem causing respiratory distress, appropriate drugs should be implemented to management accordingly.

The three signs of impending respiratory arrest are:

• Decreased level of consciousness;
• Inability to maintain respiratory effort;
• Cyanosis.

Presence of one or more of these needs immediate intervention. The untreated respiratory arrest will lead to cardiac arrest eventually. Life-threatening conditions, such as airway obstruction, acute coronary syndrome, pneumonia, cardiac tamponade, pulmonary embolism, asthma, anaphylaxis, trauma, and exacerbation of chronic obstructive pulmonary disorder may lead to respiratory distress and arrest. These critical problems should be treated during the assessment.

While you are examining the patient, other staff members (such as intern, nurse, paramedic) may measure vital parameters and monitor the patient, obtain intravenous access and do ECG. Teamwork will accelerate your assessment process and allow you to formulate a treatment plan while others obtain a history from family or friends.

History Taking and Physical Examination Hints

History Taking Hints

Acute respiratory distress is one of the most common chief complaints in the ED. The differential diagnosis includes many disorders, so a careful history can be helpful to narrow this wide differential. In addition, past medical and family history, trauma, travel, medications, allergies and exposures should be considered with common symptoms. Not only family members, but also a brief conversation with the paramedics, who transferred the patient, can give you useful information about the patient and the surrounding area they took the patient from.

Physical Examination Hints

Although we do a focused and goal-directed physical exam in critical patients, a detailed physical examination also provides important guidance.

The general appearance of patient – confusion, cyanosis, drowsiness, tachypnea, and pallor – can guide your management. Also, respiratory rate and oxygen saturation are two vital sign measurements that are helpful in assessing and monitoring the degree of respiratory distress. The higher the respiratory rate, the greater the work of breathing and the more likely the patient will eventually get tired. Oxygen saturation is important not only in assessing but also following the progress of the patient.

Pulse oximetry is a valuable monitoring tool for the management of respiratory distress patients. It is useful for either making a decision when to administer oxygen or titration of oxygen to avoid patient harm from too much oxygen.

For respiratory distress patients without immediate life threats, your next assessment focus should be to determine the patient’s work of breathing and respiratory pattern (video), looking for any tripoding or retractions. Retractions can be visualized during the assessment of chest movements, and they are more valuable than lung sounds in the decision of the respiratory distress severity.

Lung sounds (video) such as wheezing, rales, ronchi, and stridor further guide the differential diagnosis. Decreased sounds or hyperresonance may also provide additional clues. Lung sounds should be examined from both sides of the chest wall even in supine positioned patients (video). Orthopnea, or the inability to lie flat, is not a test, but rather, a question to ask the patient. Sweating and diaphoresis in an environment where others are not sweating, suggests significant distress.

Jugular venous distension (picture), S3 gallop, and peripheral edema indicate that the patient has fluid overload. Heart sounds such as murmur, or decreased sounds, guide the differential and also management. Pulses must be assessed bilaterally.

It is important to remember that anxiety is common in patients with significant medical problems, just as in trauma. COPD patients have it more often than the general population. Secondly, even healthy, young patients may have a medical cause for hyperventilation. A thorough assessment is important not to miss clues of a medical or traumatic condition.

Key findings of severe respiratory distress are 1) retractions and use of accessory muscles, 2) inability speak full sentences, 3) inability lie flat, 4) extreme diaphoresis, 5) restlessness, agitation, decreased level of consciousness.

Differential diagnosis

Having a wide differential diagnosis list for respiratory distress will allow you to sort through the possible causes more rapidly. In the ED, you must think the worst case scenarios first, and you should try to rule out them. Respiratory distress differential diagnoses list has various critical diseases. These are anaphylaxis, asthma/COPD, acute coronary syndrome, pulmonary edema, pulmonary embolism, pneumonia, pericardial tamponade, tension pneumothorax, and upper airway obstruction.

The above diagnoses are crucial and should be treated immediately. Other causes of respiratory distress should also be assessed and managed properly.

Emergency Diagnostic Tests and Interpretation

Multiple tests are available to narrow the differential diagnosis of respiratory distress. Generally, laboratory and radiological tests take a long time; you should start the treatment before getting results.

Bedside tests

• ECG, especially in elderly patients who usually present atypically with dyspnea in acute coronary syndrome, is easy and practical.

What are your diagnosis and next action about the ECG in a patient with shortness of breath and palpitation?

Case – 68 yo female presented with palpitation, dyspnea, unable to lay down. Vitals are BP: 80/43 mmHg, HR: 160 bpm, RR: 32 pm, Temp: 37 Celsius, SatO2: 87%. Patient diaphoretic, cool, anxious. Chest auscultation revealed basal to mid zone crackles on both sides. Heart sound irregular. Bilateral 1+ pitting edema.

• Bedside glucose level should be obtained in cases of a decreased level of consciousness and suspected metabolic acidosis.

Laboratory tests

• Arterial blood gas analysis is useful, quick and important to determine metabolic and/or respiratory cause of respiratory distress.
• Besides these, complete blood count (CBC), troponin, renal panel, BNP, and D-dimer can be used to assess differential diagnosis of respiratory distress.

Imaging

• Chest X-ray and Computed Tomography are generally indicated to detect and differentiate pathologies. Pneumothorax, pneumonia, pulmonary embolism, pleural effusion, cardiac tamponade, etc. are the important causes of respiratory distress.

What are your diagnoses about the chest x-rays in patients with shortness of breath?

• Currently, ultrasonography is another option in the evaluation of respiratory distress. Ultrasonography provides valuable information about the origin of symptoms and often diagnosis in the initial assessment of the patient. Also, ultrasonography is faster than laboratory tests and other imaging modalities, repeatable, and portable so that it can be used for unstable patients. It is also cost-effective.

Emergency Treatment Options

Because of a variety of diseases can cause respiratory distress and specific diseases need specific approaches such as tension pneumotorax needs decompression of the air from the chest; asthma and COPD need bronchodilator treatments. Please check each critical diagnosis separately in other chapters.

Patients often die from the complications of respiratory distress. The initial assessment is crucial, and essential interventions should be made immediately.

Respiratory distress symptoms usually have a wide range of ineffective breathing or respiratory arrest and difficulty in speaking, accompanied by cyanosis and diaphoresis.

Immediate assessment priorities for any difficulty breathing include quick determination of circulation, airway, and breathing as described above.

Disposition

if the patient’s condition or blood gas analyze does not improve despite therapy admission should be considered to appropriate clinics.

References and Further Reading

• Prekker ME, Feemster LC, Hough CL, et al. The epidemiology and outcome of prehospital respiratory distress. Acad Emerg Med 2014;21(5):543–50.
• DeVos E, Jacobson L. Approach to Adult Patients with Acute Dyspnea. Emerg Med Clin N Am 34 (2016) 129–149
• Hampson NB. Pulse oximetry in severe carbon monoxide poisoning. Chest. 1998; 114(4):1036–1041.
• Leuppi JD, Dieterle T, Koch G, et al. Diagnostic value of lung auscultation in an emergency room setting.Swiss Med Wkly. 2005;135(35–36):520–524

Links To More Information

• McEnvoy M. (2013) How to Assess and Treat Acute Respiratory Distress. Link
• CDEM Curriculum. Lewis NJ. (2015) Shortness of breath. Link
• Wolf A. Acute respiratory distress syndrome. Video Link
• UpToDate – Link
• PEM Currents podcast on respiratory distress – Link
• Flipped EM Classroom – Approach to shortness of breath. Link
• khanacademymedicine – Respiratory distress. Link
• Merck Manuals – Link
• Memrise – Raised JVP. Link
• Ahmed A, Graber MA. Evaluation of the adult with dyspnea in the emergency department. Link
• Lung Sounds. Link
• How to give Heimlich maneuver. (2012). Video Link
• ProCPR. Adult bag-valve-mask (2011). Video Link
• Flipped EM Classroom – Summary – shortness of breath. pdf Link