Related Experiment Video
Updated: Jan 15, 2026
Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
Exhaled Carbon Dioxide Monitoring Using Instantaneous CO2 Mode During High-Frequency Oscillatory Ventilation in Very
Yusuke Nakazawa1, Kazuto Ueda2, Yoshihiro Tanahashi3
1Nakazawa Kodomo Clinic, Shizuoka, Japan.
Background:
High-frequency oscillatory ventilation (HFOV) presents challenges for noninvasive CO2 monitoring due to its rapid oscillations. This study examines the feasibility of instantaneous CO2 partial pressure (INST CO2) monitoring during HFOV with a capnometer equipped with a mainstream CO2 sensor.
Methods:
This study included seven neonates receiving HFOV in the neonatal intensive care unit (NICU) at Shizuoka Children's Hospital. INST CO2 values were recorded over 3- and 5-min intervals surrounding each blood gas sampling to determine the maximum INST CO2 value (INST CO2 MX). The primary outcome was the correlation between INST CO2 MX and arterial partial pressure of carbon dioxide (PCO2).
Results:
A total of 216 paired INST CO2 MX and PCO2 values were analyzed. The coefficient of determination (R2) was 0.571 for INST CO2 MX (3 min) and 0.579 for INST CO2 MX (5 min). Univariable and multivariable analyses revealed that a lower fraction of inspired oxygen (FiO2), reduced minute ventilation, and increased postnatal age were associated with improved concordance between INST CO2 MX and PCO2.
Conclusion:
INST CO2 MX demonstrated a strong correlation with PCO2 in neonates undergoing HFOV. This novel, noninvasive monitoring approach may serve as a valuable tool for neonatal respiratory management. Future research is needed to validate these findings in broader patient populations and across various ventilatory settings.
Related Concept Videos
01:17Assessment of Diffusion and Perfusion
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...
01:14Ventilatory Modes
There are three ventilatory modes: full support, partial support, and spontaneous. These are described below.
Full Support Modes
Full support modes include controlled mechanical ventilation, continuous mandatory...
01:20Assessment of Ventilation I: Respiratory Rate
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation:
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
01:23Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation...
01:30Acute Respiratory Failure-III