Not to be disagreeable, but there is plenty of literature that validates learning under anesthesia. Although I do not recall the exact reference, there is at least one case report of awareness under general anesthesia with BIS documented 40-60 (Published within three years of BIS release in the US). Anecdotal experiences of patients receiving >5mg midazolam and propofol infusion rated from 150-300 mcg/kg/min talking to me and recalling the conversation the next day. I wouldn’t be quick to diagnose hallucinations because the discounting of recall can lead to PTSD. Acknowledging the patient‘s experiences (and that this is rare, but possible), referral to counseling is the appropriate course of action. The medical legal argument is that appropriate care was rendered and documented. Ever patient is an individual with individual responses to anesthesia.

Dear Rabiul Alam,

To my understanding there is no awareness during general anaesthesia. Those we claim to be aware during general anaesthesia are taking hallucination for reality.

Best regards,

Orlando

Dear @Orlando,

Thanks. We also think like that.

Regards-

Rabiul

Dear Rabiol,

You are welcome. It's good to know that ww both agree on the topic ar hand.

Best regards,

Orlando

Not to be disagreeable, but there is plenty of literature that validates learning under anesthesia. Although I do not recall the exact reference, there is at least one case report of awareness under general anesthesia with BIS documented 40-60 (Published within three years of BIS release in the US). Anecdotal experiences of patients receiving >5mg midazolam and propofol infusion rated from 150-300 mcg/kg/min talking to me and recalling the conversation the next day. I wouldn’t be quick to diagnose hallucinations because the discounting of recall can lead to PTSD. Acknowledging the patient‘s experiences (and that this is rare, but possible), referral to counseling is the appropriate course of action. The medical legal argument is that appropriate care was rendered and documented. Ever patient is an individual with individual responses to anesthesia.

While BIS 40 - 60 usually corresponds to GA to deep hypnotic state and unlikely to have an explicit memory, it is not that awareness can not happen. Awareness may be because of inadequate anaesthetic dose, patient factor and machine malfunction. Patient factors like resistant to anaesthetic drugs, previous history of awareness, substance use / abuse, high dose opioid dependants may not be as hypnotic and amnesic as expected with BIS or MACage monitoring. Moreover, patient also reports dream more than awareness (7% versus 2%). But what is usual teaching and current recommendation is that BIS value 40 - 60 should be targeted. to be noted that only BIS is not the sole criteria or strategy to be followed. However, as it is documented that BIS was 40 - 60, even if patient had awareness, it is beyond our control. And this itself is defending point.

I believe this is the reference I was referring:

Mychaskiw, G., Horowitz, M., Sachdev, V., & Heath, B. J. (2001). Explicit intraoperative recall at a bispectral index of 47. Anesthesia & Analgesia, 92(4), 808-809.

Cheers,

Christopher

Dear Christopher,

Thanks for your keen & kind help, indeed.

Rabiul

It sounds like everything was done properly. Awareness does happen in spite of our best intentions, including BIS monitoring.

Awareness under general anaesthesia is an oxymoron. Unfortunately, processed EEG is notoriously unreliable and, if using it, it is good practice to monitor the raw EEG signal. Important questions are: was the patient in pain (if not, awareness per se is not necessarily a big deal - we do lots of surgeries on awake patients using LA); was the patient paralysed (awareness is unusual in non-paralysed patients); what was the technique (TIVA, ketamine, gas - end tidal monitoring). You need to check your equipment, document the incident, determine what recall the patient actually describes (some will confuse time in the PACU as awareness for example). Be sympathetic and open minded about possibilities. This is not necessarily negligence.