Related Experiment Video
Updated: Dec 26, 2025
Evaluation of Capnography Sampling Line Compatibility and Accuracy when Used with a Portable Capnography Monitor
Published on: September 29, 2020
Assessment of sidestream end-tidal capnography in ventilated infants on the neonatal unit
Emma Williams1,2, Theodore Dassios1,3, Anne Greenough1,2,4
1Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.
Objectives:
Continuous monitoring of carbon dioxide (CO2 ) levels can be achieved by capnography. Our aims were to compare the performance of a sidestream capnograph with a low dead space and sampling rate to a mainstream device and evaluate whether its results correlated with arterial/capillary CO2 levels in infants with different respiratory disease severities.
Working Hypotheses:
End-tidal carbon dioxide (EtCO2 ) results by sidestream and mainstream capnography would correlate, but the divergence of EtCO2 and CO2 results would occur in more severe lung disease.
Study Design:
Prospective cohort study.
Patient-Subject Selection:
Fifty infants with a median (interquartile range) gestational age of 31.1 (27.1-37.4) weeks and birth weight of 1.37 (0.76-2.95) kg.
Methodology:
Concurrent measurements of EtCO2 in ventilated infants were made using a new Microstream sidestream device and a mainstream capnograph (gold standard). Results from both devices were compared with arterial or capillary CO2 levels. The ratio of dead space to tidal volume (Vd/Vt) was calculated to assess respiratory disease severity.
Results:
The mean difference between the concurrent measurements of EtCO2 was -0.54 ± 0.67 kPa (95% agreement levels - 1.86 to 0.77 kPa), the correlation between the two was r = .85 (P < .001). Sidestream capnography results correlated better with partial pressure of CO2 (PCO2 ) levels in infants with less (Vd/Vt < 0.35; r2 = .66, P < .001) rather than more severe (Vd/Vt > 0.35; r2 = .33, P = .01) lung disease.
Conclusions:
The sidestream capnography performed similarly to the mainstream capnography. The poorer correlation of EtCO2 to PCO2 levels in infants with severe respiratory disease should highlight to clinicians increased ventilation-perfusion mismatch.
More Related Videos
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...
01:20Assessment 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:
01:19Respiratory Assessment: Purpose and Indications
Objectives and Importance:
The primary goal of respiratory assessment is to evaluate patients at early risk of clinical deterioration. Since respiratory distress often precedes other signs of declining health, breathing patterns and sounds become a...
01:26Endoscopic Studies II: Thoracocentesis
Description
Excess pleural fluid or air may accumulate in some respiratory disorders in the thoracic cavity. To treat pleural effusion, a physician conducts thoracentesis by carefully piercing the chest wall and entering...
01:23Assessment of Respiration
Subjective Assessment: Nurses interview the patient to gather information directly during the subjective assessment. It includes questions about the individual's medical history, medications, and symptoms, focusing on past respiratory conditions like...