Arterial Blood Gas Analysis in Critically Ill Patients

Primary Sampling Protocol

For critically ill patients with chronic obstructive pulmonary disease (COPD), heart failure, or kidney disease, the American Thoracic Society recommends obtaining arterial blood samples from an indwelling arterial catheter as the first-line approach, with central venous catheter sampling as the second option if arterial access is unavailable 1, 2
The European Society of Intensive Care Medicine suggests that all patients whose severity of illness justifies invasive vascular monitoring should have arterial blood gas (ABG) samples drawn from the arterial line 3

The British Thoracic Society recommends starting oxygen therapy with a 24% Venturi mask at 2-3 L/min or 28% Venturi mask at 4 L/min, targeting SpO2 88-92% in patients with COPD 1
The American College of Chest Physicians suggests obtaining ABG within 60 minutes of starting oxygen therapy and within 60 minutes of any change in FiO2 in patients with COPD 2

The International Society for Computational Biology recommends that blood gas analyzers must perform to ±0.4 mmol/L (or ±8% above 5 mmol/L) for accurate results 3
The American Association for Clinical Chemistry suggests using only sodium chloride 0.9% (with or without heparin) for arterial line flush to avoid contamination 6

The American Thoracic Society warns that normal SpO2 does not exclude the need for ABG, as pulse oximetry may appear normal with abnormal pH or PCO2, or with anemia 1, 2, 5
The European Respiratory Society cautions that supplemental oxygen masks can hide abnormalities, and patients on oxygen therapy require ABG even with normal saturation 1, 2