I have never experienced a patient expired during my nursing career before except last night one of the colleague's patients had passed suddenly. I helped him through the process but I cannot figure it out why the patient passed. Can any more experience nurses provide some input? The pt was 68 or 75 (don't remember) who had a hip surgery ( from fall at a LTC) post-op day one with long history of mental and psych issues because the patient had a traumatic brain injury some years. Since the injury patient never been normal and always wear a protective helmet. The patient has been on numerous psych and anti-anxiety meds and was told to be extra careful because the patient known to try to commit suicide like purposefully try to choke on water or on any liquid. Anyway, patient did not have all the medications post-op but only got them last night. The vital signs were within normal range from the beginning of the shift but she died several hours later without making any noise. It appeared the patient had just passed peacefully and was a DNR. What could it be? Sepsis? MI? Combination of Medications?