Clinical manifestations are the signs and symptoms that appear in a patient as a result of an underlying disease, injury, or disturbance in body function. In critical care, careful observation of these manifestations is essential because a patient’s condition can deteriorate rapidly. Clinical manifestations may be subjective, such as pain, nausea, breathlessness, or anxiety, or objective, such as altered vital signs, cyanosis, abnormal laboratory values, and changes in level of consciousness. The major clinical manifestations commonly assessed in critically ill patients include changes in the respiratory system, cardiovascular system, neurological status, renal function, and general physical condition. Respiratory manifestations include difficulty in breathing, increased respiratory rate, use of accessory muscles, low oxygen saturation, cyanosis, abnormal breath sounds, and respiratory fatigue. Cardiovascular manifestations may include tachycardia, bradycardia, hypotension, hypertension, weak peripheral pulses, cold extremities, chest discomfort, and signs of poor tissue perfusion. Neurological manifestations include confusion, restlessness,