Blood gas analysis is of great clinical importance to determine whether the patient’s respiratory function is abnormal, whether the patient has an acid-base imbalance, and whether the patient has acidosis or alkalosis. The arterial partial pressure of oxygen, partial pressure of carbon dioxide and arterial hydrogen ion concentration are measured in most clinical cases. Blood gas analysis is widely used in clinical practice, mostly for patients with potential respiratory failure, and it can also be used to check whether the patient is anemic or ischemic.