How low must a comatose patient's blood oxygen level be to become dangerous?

Blood oxygen refers to blood oxygen saturation. If the blood oxygen saturation of a comatose patient falls below 90%, it may cause serious adverse effects on the body. The detailed analysis is as follows:

Blood oxygen saturation indicates the extent to which hemoglobin in the blood is bound to oxygen, typically expressed as a percentage. Under normal circumstances, blood oxygen saturation in humans should be above 95%. For comatose patients, low blood oxygen saturation can lead to cerebral hypoxia and further worsen their condition. Therefore, it is essential to maintain blood oxygen saturation within the normal range as much as possible. When a patient's blood oxygen saturation drops below 90%, it indicates a state of hypoxia, which may aggravate the coma and hinder effective treatment. In severe cases, it could trigger complications such as difficulty breathing or suffocation.

Different medical conditions and treatment plans may require different target levels for blood oxygen saturation. For comatose patients, doctors usually monitor and adjust oxygen levels according to the individual's specific condition to ensure that blood oxygen saturation remains within a safe range. In some cases, oxygen therapy or other interventions may be necessary to help maintain normal blood oxygen saturation levels.

Blood oxygen saturation alone should not be used as the sole indicator for assessing the health status of a comatose patient. A comprehensive evaluation must also include other vital signs such as blood pressure, heart rate, and respiration.