Midazolam-alfentanil: an anaesthetic? An investigation using the isolated forearm technique.

Thirty-two women underwent major gynaecological surgery with a midazolam-alfentanil total i.v. anaesthetic regimen. Adequacy of anaesthesia was assessed using a "pressure, rate, sweating and tears" (PRST) scoring system in conjunction with the isolated forearm technique (IFT). The IFT revealed that 72% of patients responded during surgery, but none had spontaneous, unprompted postoperative recall for the event. Three patients, on prompting, provided evidence of recall. The IFT, while indicating which patients are responsive, cannot be used to predict who will have postoperative recall. Lack of explicit postoperative recall does not indicate unconsciousness during surgery. Twenty patients, asked specifically during surgery to indicate the presence or absence of pain, experienced pain at some time during their surgical procedure. The PRST score could not be used to predict when a patient was awake. This low-dose i.v. anaesthetic technique cannot be recommended for general use.