What is the definition of respiratory failure?

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From the Guidelines

Respiratory failure is defined as a failure to maintain adequate gas exchange, characterized by abnormalities of arterial blood gas tensions, with Type 1 failure defined by a PaO2 of <8 kPa with a normal or low PaCO2, and Type 2 failure defined by a PaO2 of <8 kPa and a PaCO2 of >6 kPa. This definition is based on the study published in Thorax in 2002 1. The key characteristics of respiratory failure include:

  • Abnormalities of arterial blood gas tensions
  • Type 1 failure: PaO2 of <8 kPa with a normal or low PaCO2
  • Type 2 failure: PaO2 of <8 kPa and a PaCO2 of >6 kPa According to the study 1, respiratory failure can be defined as a clinical area staffed by appropriately trained nurses at a level higher than that of a general ward, usually one member of staff for every two patients (level 2 care). It is essential to note that respiratory failure is a serious medical condition that requires prompt intervention, as inadequate oxygen delivery to tissues can rapidly lead to organ dysfunction and death. The severity of respiratory failure is assessed through arterial blood gas analysis, which provides crucial information about the patient's oxygenation and acid-base status, as mentioned in the study 1. In clinical practice, it is crucial to recognize the signs and symptoms of respiratory failure and provide timely and appropriate treatment to improve patient outcomes and reduce morbidity and mortality.

From the Research

Definition of Respiratory Failure

Respiratory failure is defined as a failure in gas exchange due to an impaired respiratory system, which can be either pump or lung failure, or both 2. It is a condition in which the respiratory system fails in one or both of its gas exchange functions, resulting in either lung failure, leading to hypoxemia, or pump failure, resulting in alveolar hypoventilation and hypercapnia 3.

Key Aspects of Respiratory Failure

  • The hallmark of respiratory failure is impairment in arterial blood gases 2.
  • It can be caused by lung parenchymal disease, airway obstruction, or neuromuscular dysfunction 4.
  • Respiratory failure can occur due to mechanical defects, central nervous system depression, imbalance of energy demands and supplies, and/or adaptation of central controllers 5.
  • The pathophysiological mechanisms responsible for chronic carbon dioxide retention are not yet clear, but the theory of "natural wisdom" is a possible explanation 5.

Classification of Respiratory Failure

Respiratory failure can be classified into different types, including:

  • Hypoxic respiratory failure, which occurs when the lungs are unable to maintain adequate oxygenation of the blood 6, 3.
  • Hypercapnic respiratory failure, which occurs when the lungs are unable to remove enough carbon dioxide from the blood 6, 3.
  • Acute respiratory failure, which is a common cause for admission to intensive care units 3, 4.
  • Chronic respiratory failure, which can occur due to various underlying conditions, such as chronic obstructive pulmonary disease (COPD) 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Respiratory failure: an overview.

Critical care nursing quarterly, 2004

Research

Pathophysiology and Classification of Respiratory Failure.

Critical care nursing quarterly, 2016

Research

Acute Respiratory Failure in Children.

Pediatric annals, 2018

Research

Respiratory failure.

The European respiratory journal. Supplement, 2003

Research

[Respiratory Insufficiency: State of the Art - Diagnosis and Therapy].

Anasthesiologie, Intensivmedizin, Notfallmedizin, Schmerztherapie : AINS, 2018

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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