A major new study in Ireland and Britain has identified 300 cases of accidental awareness during general anaesthesia, 11 of which occurred in Ireland.
Researchers said half of the episodes led to distress and 41% to longer term psychological harm.
Accidental awareness during general anaesthesia is one of the most feared complications for patients and anaesthetists.
Most episodes of awareness identified in the study were short-lived, occurred before surgery started or after it finished.
Sensations experienced included tugging, stitching, pain, paralysis and choking.
The study found that the incidence is about one in every 19,000 cases, much lower than previously suggested.
Researchers made a series of recommendations, including the introduction of a simple anaesthesia check list that should be performed at the start of every operation.
They also called for a structured approach to the management of patients who report awareness.
Project lead professor Jaideep Pandit said: "We found that patients are at higher risk of experiencing accidental awareness during general anaesthesia (AAGA) during caesarean section and cardiothoracic surgery, if they are obese or when there is difficulty managing the airway at the start of anaesthesia.
"The use of some emergency drugs heightens risk, as does the use of certain anaesthetic techniques.
"However, the most compelling risk factor is the use of muscle relaxants, which prevent the patient moving."
