Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Respiratory Volumes and Capacities01:22

Respiratory Volumes and Capacities

The respiratory system is responsible for the intake of oxygen and the expulsion of carbon dioxide from the body. Respiratory volumes describe the volume of air in the lungs at different phases of the respiratory cycle. Tidal volume is the air breathed in and out during normal, quiet breathing. Inspiratory reserve volume is the air that can be forcefully inspired beyond the tidal volume. In contrast, expiratory reserve volume refers to the air that can be expelled from the lungs after a normal...
External and Internal Respiration01:24

External and Internal Respiration

External respiration occurs in the lungs, and it is the first step in the journey of oxygen inside the body. When we inhale, oxygen enters our lungs and diffuses across the thin alveolar membrane. The alveoli are tiny, air-filled sacs that provide a vast surface area for gas exchange. Oxygen in the alveoli has a higher partial pressure (105 mmHg) than in the adjacent pulmonary capillaries (40 mmHg), establishing a pressure gradient. As a result, oxygen molecules move from the alveoli into the...
Pressure Relationships in Thoracic Cavity01:24

Pressure Relationships in Thoracic Cavity

Breathing, otherwise known as pulmonary ventilation, is the process of air movement into and out of the lungs. The main mechanisms propelling pulmonary ventilation are atmospheric pressure (Patm), intra-pulmonary (Ppul ) or intra-alveolar pressure (Palv) within the alveoli, and intrapleural pressure (Pip) within the pleural cavity.
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs during...
Physical Principles Governing Gas Exchange01:16

Physical Principles Governing Gas Exchange

Gas behavior plays a vital role in understanding bodily processes such as external and internal respiration. External respiration involves the diffusion of oxygen into the blood and carbon dioxide out of it in the lungs. In contrast, internal respiration happens in body tissues, where these gases move in opposite directions.
Gas Laws Governing Respiration
The behavior of gases is guided by Dalton's Law of partial pressures and Henry's Law.
Dalton's Law asserts that the total pressure exerted by...
Atelectasis II: Pathophysiology01:10

Atelectasis II: Pathophysiology

Atelectasis develops when alveoli lose their air and collapse inward. Because lung tissue is naturally elastic, these air sacs shrink rather than remaining open. Collapsed alveoli are no longer ventilated, reducing their role in gas exchange. Blood flow may continue in these regions, creating a ventilation–perfusion mismatch. Clinical findings include decreased breath sounds, dullness to percussion, reduced chest expansion, and decreased tactile fremitus as sound transmission through collapsed...
Lung Capacity01:47

Lung Capacity

The air in the lungs is measured in volumes and capacities. Lung volume measures reflect the amount of air taken in, released, or left over after a lung function, like a single inhalation. Lung capacity measures are sums of two or more lung volume measures.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Post-dural Puncture Headache in Dural Puncture Epidural and Combined Spinal-Epidural Using 24- and 25-Gauge Needles Versus Conventional Epidural Labor Analgesia: A Systematic Review and Meta-analysis.

Anesthesia and analgesia·2026
Same author

Bayesian Analysis of Postoperative Complication Risk Associated With Preoperative Exposure to Fine Particulate Matter: A Single-Center Cohort Study.

Acta anaesthesiologica Scandinavica·2026
Same author

Disparities in Antiemetic Prophylaxis Care Processes Predicted by Patient Neighborhood: Retrospective Cohort and Geospatial Analysis.

JMIR public health and surveillance·2026
Same author

In Response.

Anesthesia and analgesia·2025
Same author

Peripheral venous blood gas analysis for the diagnosis of respiratory failure, hypercarbia and metabolic disturbance in adults.

The Cochrane database of systematic reviews·2025
Same author

Single-Syringe Total Intravenous Anesthesia With Propofol and Remifentanil: A Prospective Cohort Study.

Anesthesia and analgesia·2025
Same journal

Active Warming Using Heated Inspired Gas: Full of Hot Air?

Respiratory care·2026
Same journal

Work of Breathing by the Campbell Diagram: Physiology and Practice.

Respiratory care·2026
Same journal

Inhaled Sedation in the ICU.

Respiratory care·2026
Same journal

Risk Stratification Using the Tracheostomy Early Prediction Score and the Association Between Early Tracheostomy and Mortality in Sepsis.

Respiratory care·2026
Same journal

Editor's Commentary.

Respiratory care·2026
Same journal

Response to the Letter to the Editor Regarding "Comparative Evaluation of Risk Scores for Predicting Postoperative Pulmonary Complications".

Respiratory care·2026
See all related articles

Related Experiment Video

Updated: Jul 4, 2026

Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship
08:25

Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship

Published on: January 8, 2019

Anatomic dead space cannot be predicted by body weight.

Lara M Brewer1, Joseph A Orr, Nathan L Pace

  • 1Department of Anesthesiology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA. lbrewer@abl.med.utah.edu

Respiratory Care
|July 3, 2008
PubMed
Summary
This summary is machine-generated.

Estimating anatomic dead space using patient weight is inaccurate. Direct measurement is crucial for precise ventilation, especially with modern low tidal volume protocols.

More Related Videos

Quantitative Measure of Lung Structure and Function Obtained from Hyperpolarized Xenon Spectroscopy
08:23

Quantitative Measure of Lung Structure and Function Obtained from Hyperpolarized Xenon Spectroscopy

Published on: November 10, 2023

Intraperitoneal Glucose Tolerance Test, Measurement of Lung Function, and Fixation of the Lung to Study the Impact of Obesity and Impaired Metabolism on Pulmonary Outcomes
08:30

Intraperitoneal Glucose Tolerance Test, Measurement of Lung Function, and Fixation of the Lung to Study the Impact of Obesity and Impaired Metabolism on Pulmonary Outcomes

Published on: March 15, 2018

Related Experiment Videos

Last Updated: Jul 4, 2026

Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship
08:25

Combining Volumetric Capnography And Barometric Plethysmography To Measure The Lung Structure-function Relationship

Published on: January 8, 2019

Quantitative Measure of Lung Structure and Function Obtained from Hyperpolarized Xenon Spectroscopy
08:23

Quantitative Measure of Lung Structure and Function Obtained from Hyperpolarized Xenon Spectroscopy

Published on: November 10, 2023

Intraperitoneal Glucose Tolerance Test, Measurement of Lung Function, and Fixation of the Lung to Study the Impact of Obesity and Impaired Metabolism on Pulmonary Outcomes
08:30

Intraperitoneal Glucose Tolerance Test, Measurement of Lung Function, and Fixation of the Lung to Study the Impact of Obesity and Impaired Metabolism on Pulmonary Outcomes

Published on: March 15, 2018

Area of Science:

  • Respiratory Physiology
  • Mechanical Ventilation
  • Pulmonary Diagnostics

Background:

  • Anatomic dead space, the volume of air not participating in gas exchange, is critical in mechanical ventilation.
  • Current protocols advocate for smaller tidal volumes, increasing the relative impact of dead space.
  • Traditional estimation methods rely on body weight (1 mL/lb), a practice potentially outdated.

Purpose of the Study:

  • To evaluate the accuracy of common anatomic dead space estimation methods.
  • To compare weight-based estimations against direct measurements using volumetric capnography.
  • To determine the reliability of predicting dead space from patient weight alone.

Main Methods:

  • Analysis of data from 58 patients undergoing respiratory monitoring.
  • Direct measurement of anatomic dead space using the Fowler method with volumetric capnography.
  • Comparison of measured dead space with estimates derived from patient body weight.

Main Results:

  • The correlation between weight-based dead space estimates and measured values was extremely poor (r² = 0.0002).
  • The mean error for weight-based estimates was 60 ± 54 mL, indicating significant individual variability.
  • Direct measurement via volumetric capnography offers a more precise assessment.

Conclusions:

  • Weight-based estimation of anatomic dead space is unreliable for individual patient assessment.
  • While historical methods may have served as initial guides, they lack precision for current ventilation strategies.
  • Accurate measurement of anatomic dead space is essential for optimizing mechanical ventilation, particularly with lung-protective strategies.