Related Experiment Video
Updated: Jun 19, 2026
07:52
Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
THE RESPIRATORY RESPONSE TO CARBON DIOXIDE.
H W Davies1, G R Brow, C A Binger
1Hospital of The Rockefeller Institute for Medical Research.
The Journal of Experimental Medicine
|October 30, 2009
Summary
This study details a method to measure the respiratory response to carbon dioxide (CO2) using a mathematical formula. The findings reveal how ventilation adjusts to CO2 levels and oxygen concentration, and describe components of respiratory fatigue.
Area of Science:
- Physiology
- Respiratory Medicine
- Biophysics
Background:
- Understanding the human respiratory system's response to varying carbon dioxide (CO2) levels is crucial for diagnosing and managing respiratory conditions.
- Previous methods for assessing ventilatory control have limitations in precision and scope.
Purpose of the Study:
- To introduce a novel technique for quantifying the respiratory response to inhaled carbon dioxide (CO2) based on the Peabody principle.
- To establish a mathematical model describing the relationship between ventilation and CO2 concentration.
- To investigate the influence of varying oxygen concentrations on this respiratory response.
Main Methods:
- Development and application of a technique measuring respiratory response to controlled carbon dioxide (CO2) inhalation.
- Utilizing the Peabody principle to assess pulmonary ventilation.
- Mathematical modeling (Y = K + ab(z)) to represent the ventilation-CO2 relationship.
Main Results:
- A formula (Y = K + ab(z)) was derived, defining individual respiratory responses to CO2.
- Total pulmonary ventilation showed a slightly enhanced response at high oxygen percentages (90%+) compared to normal levels.
- Respiratory fatigue was characterized by distinct nervous (increased excitability) and muscular (reduced capacity) components.
Conclusions:
- The described technique provides a quantifiable measure of the respiratory response to CO2.
- Individual respiratory control can be mathematically characterized, with variations influenced by oxygen levels.
- Respiratory fatigue involves both central neural and peripheral muscular factors, impacting ventilatory capacity differently.
Related Concept Videos
01:31Chemical Factors Affecting Respiration Centers
Chemical factors such as changing CO2, O2, and H+ levels in arterial blood play a critical role in influencing respiration depth and rates. These variations are detected by chemoreceptors—specialized sensors located in two primary body areas. Central chemoreceptors are found throughout the brain stem, including the ventrolateral medulla, while peripheral chemoreceptors are located in the aortic arch and carotid arteries.
CO2 has a potent influence on respiration and is strictly regulated. Under...
CO2 has a potent influence on respiration and is strictly regulated. Under...
01:18Respiratory Regulation of Acid-Base Balance
Respiratory compensation is a vital physiological process that stabilizes blood plasma pH by regulating the partial pressure of carbon dioxide (PCO2), a key determinant of pH levels. Most carbon dioxide in the blood dissolves and converts into carbonic acid (H2CO3). It dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3⁻). There is also an inverse relationship between PCO2 and pH.
When carbon dioxide levels increase in the blood, more H+ and HCO3⁻ are produced, leading to a...
When carbon dioxide levels increase in the blood, more H+ and HCO3⁻ are produced, leading to a...
01:17Assessment of Diffusion and Perfusion
Understanding and evaluating diffusion and perfusion is critical in assessing a patient's respiratory and circulatory health. These processes play key roles in maintaining the body's internal environment, ensuring that tissues receive adequate oxygen while waste products are efficiently removed.
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this principle...
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this principle...
01:23Physiological Control of Respiration
Introduction
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
01:19Carbon Dioxide Transport in the Blood
Carbon dioxide (CO2) transport in the blood is critical to human physiology. On average, our body cells produce around 200 mL of CO2 per minute, precisely the quantity expelled by the lungs. This process involves the transportation of CO2 from the tissue cells to the lungs in three primary forms.
Forms of CO2 Transport
1. Dissolved in plasma: A small percentage (7-10%) of CO2 is transported and dissolved directly in the plasma.
2. Carbaminohemoglobin: Just over 20% of CO2 is chemically bound to...
Forms of CO2 Transport
1. Dissolved in plasma: A small percentage (7-10%) of CO2 is transported and dissolved directly in the plasma.
2. Carbaminohemoglobin: Just over 20% of CO2 is chemically bound to...
01:30Acute Respiratory Failure-III
Hypercapnic respiratory failure, also known as Type 2 or ventilatory respiratory failure, is a severe condition characterized by the body's inability to effectively remove carbon dioxide (CO2) from the bloodstream. It leads to an arterial CO2 pressure (PaCO2) exceeding 45 mmHg and a blood pH above 7.35. This situation indicates that the body's ventilatory demand, or the ventilation needed to maintain normal PaCO2 levels, surpasses its supply or the maximum gas flow achievable without causing...