Having more than one operation during the same hospitalization or in a short time span is more lethal. The very young and very old are at the highest risk. Risk rises with concurrent disease especially heart or lung problems. Recent myocardial infarction carries a risk of fatal infarction following anesthesia. Risk of reinfarction declines to near normal when six months or more have elapsed between original infarct and anesthesia.
Emergency procedures carry a much higher mortality rate during the recovery period.
Mortality rates probably rise during the evening and night when fewer nurses are present, and during shift changes. Persistent myoneural blockage and relative anesthetic overdose are commonly associated with post-anesthesia mortality 8. Human error is associated with most disasters unless concurrent disease states dominate. Risk of postoperative anesthetic-related death diminishes when the patient is not transferred from one unit of a hospital to another until he is fully awake. 10 Anesthetic risk is probably inversely proportional to the number of cases done by each anesthetist in a given day and inversely proportional to the ratio of recovery room nurses to occupant.