Whereas there are occasional failures with spinals, epidurals and nerve blocks, a general anaesthetic always works! If the spinal or epidural is not completely effective it is generally an easy matter to convert to a general anaesthetic.
With general anaesthesia some patients may need more or less anaesthetic than others, and your anaesthesiologist’s skill and experience ensure that you get the right amount of anaesthetic. But there have been rare reports of patients being aware under the anaesthetic. This usually occurs because the anaesthesiologist is having to give a very light anaesthetic because of a poor underlying medical condition and dangerous depression of heart activity by the anaesthetic agents.
While this may seem awful, it is not a catastrophe provided the anaesthesiologist has kept the patient free of pain, and the drugs given for analgesia do not depress the heart to nearly the same extent as the other anaesthetic drugs.
Remember that many operations are performed with the patient wide-awake, for example operations performed under spinal or epidural anaesthesia. There have, however, been very isolated accidents where a patient has had vivid recall of the operation and has been distressed because pain relief was incomplete. These have occurred when there has been an error in the anaesthetic delivery system. In these circumstances the emotional distress can cause a type of post-traumatic stress syndrome, and it is very important that a psychologist counsels such patients.
Post-Traumatic Stress Disorder Description