Related Experiment Video
Updated: Aug 15, 2026
Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
Capillary blood gases in acute exacerbations of COPD
Ross Murphy1, Sanjeet Thethy, Simon Raby
1Department of Accident and Emergency Medicine, The Royal Infirmary of Edinburgh, Old Dalkeith Road, Little France, Edinburgh EH16 4SU, UK.
Objectives:
To assess the correlation and agreement between measurements of PO(2), PCO(2), H(+) and HCO(3)(-) in arterial and capillary blood in patients with acute exacerbations of COPD. To assess the repeatability of capillary measurements.
Design:
Method comparison study.
Setting:
Accident and emergency department in a university teaching hospital.
Main Outcome Measures:
Measurements of PO(2), PCO(2), H(+) and HCO(3)(-) in one arterial and two capillary samples taken from consecutive patients with acute exacerbations of COPD.
Results:
The agreement between measurements of PCO(2), H(+) and HCO(3)(-) in arterial and capillary blood was good with mean differences of 0.087 kPa, 1.044 nmol/l and 0.513 mmol/l, respectively. The corresponding 95% limits of agreement were narrow. The agreement between measurements of PO(2) was poor with a mean difference of 1.256 kPa and wide 95% limits of agreement. There was good repeatability between capillary samples with mean differences of 0.094 kPa, 0.674 nmol/l and 0.028 mmol/l for measurements of PCO(2), H(+) and HCO(3) respectively and narrow coefficients of repeatability.
Conclusions:
Capillary blood gas measurements provide an accurate assessment of PCO(2), H(+) and HCO(3)(-) and can be used to reliably measure the ventilatory status of patients. Combined with continuous pulse oximetry they can be used as an alternative to arterial blood gas measurements in patients with acute exacerbations of COPD.
More Related Videos
08:44Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method
Published on: February 2, 2024
07:09Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise
Published on: February 20, 2017
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 principle...
01:27Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
01:30Acute Respiratory Failure-III
01:24Diagnosing Acidosis and Alkalosis
First, the pH level is assessed to determine whether the blood pH is normal (7.35–7.45), low (acidosis), or high (alkalosis).
Next, the PCO2 and HCO3− values are examined to...
01:21Acute Respiratory Failure-II
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
01:21Acute Respiratory Failure-I
Definition: It is defined by specific criteria based on blood gas measurements. Hypoxemia happens when the partial pressure of oxygen (PaO2) falls below 60 mmHg. At the same time,...