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Review the types & causes of respiratory failure, and how to care for these patients on the go when you listen here or straight from your favorite podcast player.

Respiratory failure occurs when the respiratory system can no longer adequately meet the oxygen demands of the body, remove carbon dioxide effectively, or both. There are two main types of respiratory failure: hypoxemic respiratory failure and hypercapnic respiratory failure.

  • Hypoxemic respiratory failure – PaO2 and SpO2 are low. CO2 may be normal or low because CO₂ diffuses much more easily than oxygen across the lungs. So even when the lungs aren’t able to provide enough oxygen to the blood, they are usually able to maintain the ability to expel CO₂. The main problem here is oxygen. 
  • Hypercapnic respiratory failure – PaCO2 and ETCO2 are elevated and the patient is often in respiratory acidosis. The problem here is with ventilation.

Oxygenation vs ventilation

Oxygenation is the body’s process of transferring oxygen across the alveolar-capillary membrane and delivering it to the body’s tissues. Oxygenation can be improved through supplemental oxygen and through assisted ventilation.

Ventilation, on the other hand, is the process of moving air in and out of the lungs. It brings oxygen to the alveoli and removes carbon dioxide. Ventilation cannot be improved with the administration of oxygen alone. The patient’s ventilatory effort must be supported. This could be through a noninvasive mechanism such as BiPAP or a BVM. In severe cases, mechanical ventilation is utilized.

Common causes of hypoxemic respiratory failure:

  • Pneumonia – the alveoli fill with inflammatory fluid which reduces the available surface area for gas exchange
  • Pulmonary edema – the alveoli fill with fluid
  • ARDS – severe inflammatory lung injury
  • Pulmonary embolism – a blood clot impedes blood flow in the pulmonary vasculature, which reduces gas exchange
  • Severe atelectasis – the alveoli collapse

Common causes of hypercapnic respiratory failure:

  • COPD exacerbation or severe asthma – airflow obstruction
  • Opioid-induced respiratory depression – hypoventilation leads to buildup of carbon dioxide
  • Neuromuscular disorders – examples include Guillan-Barré, myasthenia gravis and spinal cord injury
  • Obesity hypoventilation syndrome – a complex condition related to three key mechanisms: 1) sleep apnea; 2) hypoventilation; and 3) reduction in lung volume and diaphragm motion due to excess adipose tissue

Now that you’ve got some background information on the types and causes of respiratory failure, let’s learn how to care for these patients using the Straight A Nursing LATTE method.

L: How does the patient LOOK? Signs and symptoms of respiratory distress and respiratory failure

Early recognition and treatment are vital when faced with a patient experiencing respiratory difficulty. If respiratory distress is not corrected, the patient will progress to respiratory failure, and potentially complete respiratory and cardiovascular collapse.

Subtle early signs – Very early signs that your patient could be in respiratory trouble include anxiety and restlessness. Since many things can cause these symptoms, they often get overlooked, which is why a full assessment is always a good idea any time your patient has a change in condition.

More obvious early signs – More obvious signs include tachypnea, shortness of breath, and increased work of breathing.

As things progress – Your patient is definitely in trouble if you see accessory muscle use, retractions, nasal flaring, severe tachypnea, confusion, and the inability to speak more than a few words at a time (or at all).

Late signs – Somnolence, cyanosis, and decreased respiratory effort are all ominous signs. This patient is on the verge of respiratory and cardiac arrest. Immediate intervention must be the highest priority.

A patient who was restless previously who is now suddenly quiet is a huge cause for concern. Assess SpO2 and ETCO2, then intervene appropriately.

A: What ASSESSMENTS will you perform?

A general respiratory assessment is going to be heavily reliant on what you see and hear. Your assessment will also be guided by any underlying respiratory disorders and what is currently going on with the patient’s physiology and plan of care. I walk you through each step of a respiratory assessment in this article.

T: What TESTS are conducted for a patient to evaluate respiratory failure?

  • Pulse oximetry – Pulse oximetry measures SpO2, which is peripheral oxygen saturation. It represents the percentage of oxygenated hemoglobin relative to the total hemoglobin in the blood. 
  • ETCO2 – This device measures carbon dioxide, specifically the amount of carbon dioxide that’s exhaled at the end of a breath. It is a direct measure of ventilation and is elevated in hypercapnia. I’ve got a quick podcast episode on ETCO2 that dives a little deeper into what ETCO2 is really measuring. Listen here or find episode #496 of the Straight A Nursing podcast wherever you like to listen from.
  • Arterial blood gas – The ABG looks at the partial pressure of oxygen and carbon dioxide dissolved in arterial blood. It also measures pH, bicarbonate, base deficit and other important factors that help guide patient care in acid-base disorders.
  • Chest X-ray – Chest X-rays are utilized to evaluate a wide range of respiratory conditions including infectious disease and pulmonary edema.

T: What TREATMENTS are provided?

The two mainstays of treatment for respiratory failure are oxygen therapy and ventilatory support, and these are loosely aligned with the type of respiratory failure. In addition, it’s also vital to address the underlying cause. Depending on what that is, treatments could include things like:

  • Antibiotics to treat infection
  • Bronchodilators to treat COPD or asthma
  • Diuretics to treat pulmonary edema
  • Thrombolytics to treat pulmonary embolism
  • Naloxone to treat opioid overdose 

Hypoxemic respiratory failure – In the early stages of hypoxemic respiratory failure, the patient likely only needs oxygen therapy and treatments directed at the underlying cause. However, once respiratory failure sets in, they will likely need both oxygen and ventilation support.

Hypercapnic respiratory failure – Patients in hypercapnic respiratory failure will always need ventilation assistance so they can “blow off” the excess CO2. Oxygen is also typically low in these patients, so oxygen therapy is usually warranted as well. And, of course, we will need to address the underlying cause.

Oxygenation devices utilized include the nasal cannula, simple face mask, oxymask and non-rebreather. For ventilation support, BVM (assisted ventilation with a bag valve mask), CPAP, BiPAP and mechanical ventilation are utilized.

E: What EDUCATION is most important?

Patient education should align with the underlying cause of the patient’s respiratory failure. This could include things like:

  • Smoking cessation
  • Proper use of inhaled medication such as albuterol and fluticasone
  • The importance of coughing and deep breathing to prevent pneumonia
  • How to recognize signs of fluid overload, which can culminate in pulmonary edema
  • Using a CPAP machine
  • Performing ankle pumps or wearing SCDs while in bed to prevent DVT (and ultimately a pulmonary embolism)
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Case Study #1

A 72-year-old patient has presented to the emergency room with signs of community acquired pneumonia. During your assessment, you note:

  • Respiratory rate: 28
  • Heart rate: 110
  • Temperature: 101.8°F
  • SpO₂: 84% on room air
  • Crackles in the right lower lobe
  • Increasing shortness of breath

The patient is alert and oriented but appears anxious.

An arterial blood gas reveals:

  • PaO₂: 55 mmHg
  • PaCO₂: 38 mmHg

Is the patient’s problem oxygenation or ventilation?

Is carbon dioxide normal or abnormal?

What type of respiratory problem is this? Hypoxemic or hypercapnic?

What are your nursing priorities?

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Case Study #2

A 68-year-old patient is recovering from surgery. He has a history of obstructive sleep apnea and obesity. Over the last hour, he has received several doses of opioid pain medication from his PCA, which also has a basal rate running. During your assessment, you note:

  • Respiratory rate: 8
  • SpO₂: 93% on 3 liters nasal cannula
  • ETCO₂: 58 mmHg
  • Increasing drowsiness
  • Difficult to keep awake

At first glance, this patient may not look as concerning. After all, the oxygen saturation is 93%. But let’s dive into this one.

Is the patient ventilating adequately?

What is this doing to carbon dioxide levels?

What type of respiratory problem is this? Hypoxemic or hypercapnic?

What are three priority non-invasive interventions?

That doesn’t work and your patient deteriorates…what’s your plan?

Key takeaways (TL;DR)

  • Respiratory failure is failure of oxygenation, ventilation, or both.
  • Hypoxemic respiratory failure = oxygenation problem.
  • Hypercapnic respiratory failure = ventilation problem.
  • Respiratory rate, work of breathing, and mental status are critical assessments.
  • Early recognition and intervention can prevent intubation, respiratory arrest, and cardiac arrest.

Want more respiratory topics? Dive in here!

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The information, including but not limited to, audio, video, text, and graphics contained on this website are for educational purposes only. No content on this website is intended to guide nursing practice and does not supersede any individual healthcare provider’s scope of practice or any nursing school curriculum. Additionally, no content on this website is intended to be a substitute for professional medical advice, diagnosis or treatment.

References:

Chung, Yewon, et al. “Causes of Hypercapnic Respiratory Failure and Associated In‐hospital Mortality.” Respirology (Carlton, Vic.), vol. 28, no. 2, Feb. 2023, pp. 176–82. PubMed Central, https://doi.org/10.1111/resp.14388.

Cleveland Clinic. “Blood Oxygen Level.” Cleveland Clinic, 18 Feb. 2022, https://my.clevelandclinic.org/health/diagnostics/22447-blood-oxygen-level.

FS, Samuel M. Galvagno Jr, DO, Maj, USAFR, MC. “Understanding Ventilation Vs. Oxygenation Is Key in Airway Management.” JEMS: EMS, Emergency Medical Services – Training, Paramedic, EMT News, 19 Nov. 2012, https://www.jems.com/patient-care/airway-respiratory/understanding-ventilation-vs-oxygenation/.

Masa, Juan F., et al. “Obesity Hypoventilation Syndrome.” European Respiratory Review, vol. 28, no. 151, 2019, https://publications.ersnet.org/content/errev/28/151/180097.

Mayo Clinic. “Low Blood Oxygen (Hypoxemia) Causes.” Mayo Clinic, 7 Oct. 2025, https://www.mayoclinic.org/symptoms/hypoxemia/basics/causes/sym-20050930.

Mosesso Jr, Vincent N., and Angus M. Jameson. “Oxygenation and Ventilation.” Emergency Medical Services, Wiley Online Library, 2021, https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119756279.ch6.

Last Updated on August 22, 2026 by Maureen Osuna, MSN, RN