• The incidence of awareness with explicit recall in the BIS versus MAC alert groups. [ Designated as safety issue: Yes ]
  

• Meta-Analysis of awareness events in conjunction with the BAG-RECALL study based at Washington University. [ Designated as safety issue: Yes ]
  
• Incidence of Post-traumatic stress disorder. [ Designated as safety issue: Yes ]
  
• Predictors of post-traumatic stress disorder based on the type of awareness event. [ Designated as safety issue: Yes ]
  
• Incidence and type of dreams during anesthesia in conjunction with MAC or BIS values. [ Designated as safety issue: No ]
  
• The relationship between cumulative deep hypnotic time, anesthetic doses, and mortality. [ Designated as safety issue: Yes ]
  
• Relationship between BIS values and hemodynamic parameters. [ Designated as safety issue: Yes ]
  
• Analysis of interrupted monitoring during the use of the BIS. [ Designated as safety issue: Yes ]
  
• Effect of electronic alerts on the clinical behavior of the anesthesia provider. [ Designated as safety issue: No ]
  
• BIS values and anesthetic dosing of chronic pain patients. [ Designated as safety issue: No ]
  
• Overall use of anesthetics comparing the BIS to MAC alerts. [ Designated as safety issue: No ]
  
• PACU pain scores, neurologic exam, and discharge time in relationship to BIS values. [ Designated as safety issue: Yes ]
  
• Incidence of post-operative nausea and vomiting in relationship to BIS values. [ Designated as safety issue: Yes ]
  
• Anesthetic induction doses, hypotension, and BIS values. [ Designated as safety issue: Yes ]
  

Electronic alerts have been developed and employed at our institution and have been shown to increase compliance with both clinical and administrative tasks (O'Reilly et al, 2006; Kheterpal et al, 2007). We have developed electronic alerts for the purpose of informing the clinician of potentially insufficient anesthesia based on minimum alveolar concentration (MAC). The algorithm is as follows:

• Every 5 minutes the alerting system checks every active case in our operating rooms. It takes approximately 1 second for this scan of all active cases to occur.

• Conditions for an "active case" are:

  1. data capture is possible (i.e., not a paper record)
  2. data capture is active (i.e., "patient in room" has been electronically entered and end-tidal [Et] CO2 is detected)
  3. "anesthesia induction end" has already been documented
  4. request for recovery room bed or transport to an intensive care unit has NOT been documented

• The alerting system checks the MOST RECENT value in the last 5 minutes of

  1. Et Sevoflurane (MAC-2.0)
  2. Et Isoflurane (MAC-1.2)
  3. Et Nitrous Oxide (MAC-105) and compares to the MAC of each agent. It adds the resulting MACs together.
• It then checks for a propofol infusion in mcg/kg/min and divides by 150, assuming that 150 mcg/kg/min is 1.0 MAC for propofol. The analogous concept of MAC for propofol is "Cp50"- the plasma or blood concentration at which 50% of patients do not move in response to a noxious stimulus. Since we do not have the technology at our institution to routinely analyze intraoperative propofol levels (and thus cannot establish a Cp50-awake), we have chosen the above dose based on clinical experience.
• It then checks for a dexmedetomidine infusion with a rate of 0.2 mcg/kg/min or greater. If present, it adds 0.50 to the current total MAC, as dexmedetomidine can reduce MAC by 50% (Aantaa et al, 1997).
• The "current" MAC is then defined as: Et Sevo /2 + Et Iso / 1.2 + Et Nitrous /105 + propofol rate/100 + 0.50 if dexmedetomidine is >/- 0.2 mcg/kg/min.
• If this total mac < 0.50, it checks to see if a bolus of propofol, midazolam, etomidate, or thiopental has been given in the preceding 10 minutes.
• It alerts the clinician signed into the case within 30-60 seconds if total age-adjusted MAC < 0.50 AND no bolus has been documented in the last 10 minutes.

This will be the protocol in the MAC-guided group. In the BIS-guided group an electronic alert will be sent if the BIS value is >60.

We are collaborating with Washington University, the University of Chicago, and the University of Mannitoba, who will also be testing a MAC-based protocol in comparison to the BIS.