Respiratory failure is a common critical illness in clinical settings, characterized by serious impairments in the lung's ventilation and gas exchange functions. What are the symptoms after respiratory failure? First and foremost, the earliest and most obvious symptom is difficulty breathing. Many patients experience significant difficulty breathing; severe cases may even involve orthopnea, profuse sweating, and inability to speak. Another important symptom is cyanosis, which is a typical manifestation of hypoxia. Additionally, there can be neuropsychiatric symptoms such as mental confusion, agitation, convulsions, and even coma. Other systems may also exhibit symptoms, such as tachycardia, arrhythmias, and decreased gastrointestinal function.