Dealing with hypothermia is fairly simple: heat the person up (you have a machine in medbay for this purpose, or can use leporazine if they are too cold), keep them well fed and ensure they do not have any alcohol (this will speed up heat loss). You are unlikely to have to deal with hypothermia in space unless someone's tried spacewalking lately, but may do if a patient spends too long outside planetside, especially when there is snow. Hypothermia is defined as a body core temperature below 35.0 °C (95.0 °F). Symptoms depend on the temperature. In mild hypothermia there is shivering and mental confusion. In moderate hypothermia shivering stops and confusion increases. In severe hypothermia there may be paradoxical undressing, where a person removes their clothing, as well as an increased risk of the heart stopping.
Body temperature: 32C - 35C Symptoms: Slow, shivering.
Body temperature: 28C - 32C Symptoms: Extremely slow, no longer shivering. May slur words, May stutter. May drop items, may collapse. Likely to be more dizzy & less able to use machines.
Body temperature: 24C - 28C Symptoms: Passed out. Low (~30) BPM, may be taking oxygen damage. (25% of taking 5 damage a tick - but it depletes as you are still breathing)
Body temperature: <24C Symptoms: Passed out, 0 BPM, Not Breathing, may be taking oxygen damage (25% chance a tick of getting 5 oxyloss. Does not deplete as you are not breathing)