Awareness and recall in anesthesia


Awareness and recall in anesthesia are rare complications during surgery. They appear in general anesthesia and can be horrific events that leave mental problems behind. Let’s read to know more about awareness and recall in anesthesia.

What are awareness and recall in anesthesia?

In general anesthesia, patients are given medications to be unconscious and to relieve pain. But, in some cases, the medications fail and awareness occurs. The patients can wake up and they know about things happening during the surgery. If the aim of pain relief fails, the patients can even feel painful. It is dangerous that sometimes, the sleep and pain management purposes fail but the paralytic agent does not, so the patients cannot talk about their situation to the anesthesia providers and seek help.

Frequency of awareness

Awareness anesthesia is uncommon. About 0.1% to 0.2% of cases reported that they experienced awareness. At other levels of awareness, patients may or may not feel painful, or some feel the pressure. But, patients should know that severe awareness and recall are rarely.


Awareness anesthesia can leave some psychological problems behind for the patients, such as depression, anxiety and post-traumatic stress disorder (PTSD). A large number of patients who has suffered awareness and recall fears future surgery and anesthesia.

Risk factors

The causes of awareness and recall in anesthesia include multiple risk factors. According to epidemiological studies, risk factors can be categorized into three main groups. These are described below.

Inadequacy of anesthetic dose

The dose of medications used for anesthesia depends on patient’s expected requirement. The inadequacy of anesthetic dose occurs due to some errors including the omission or late commencement of a volatile agent, or failure to recognize the signs of awareness. Sometimes, under-dose happens in some scenarios when the anesthetic is used to maintain the arterial pressure. These scenarios are cardiac surgery, emergency caesarean section delivery.

Resistance to anesthetic

Factors associated with the resistance to anesthetic include obesity; anxiety; young age; tobacco use; alcohol abuse; use of recreational drugs such as cocaine, amphetamines; pregnancy; hypertension.

Anesthetic techniques malfunction

Breathing system malfunctions and disconnections have been associated with awareness. In some unexpected cases, the machine goes wrong and the connection is disconnected, so the patient cannot receive a right amount of anesthetic, awareness and recall might happen.


The risk of awareness and recall in anesthesia can be minimized by using some recommendations below.

Pre-operative evaluation

  • An anesthesia provider will ask for the patient’s family history (through past medical records, asking patient and patient’s family).
  • Use a physical examination to estimate the dose of anesthetic.
  • Find out patient’s risk factors associated with anesthesia and surgery.
  • Estimate the chance of experiencing awareness and recall during surgery.

Pre-induction of general anesthesia

  • Check the anesthesia system’s function before induction.
  • Premedication with benzodiazepines, or administration of benzodiazepines during induction.

Intraoperative management

  • Use a higher level of anesthesia immediately if the anesthesia providers suggest that the patient may be experiencing noxious stimuli.
  • Be sure that all the indexes are under control.

Postoperative interventions

  • Talk with the patient if awareness and recall were reported.
  • Provide psychological counseling or support.

Patients should not be afraid of awareness and recall in anesthesia. Just remember that modern surgery is worked through the miracle of anesthesia and there is only a small number of severe awareness cases was reported.

Hello Health Group does not provide medical advice, diagnosis or treatment.

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