A survey of propofol abuse in academic anesthesia programs

Anesth Analg 2007;105:1066-1071

Wischmeyer PE, Johnson BR, Wilson JE, Dingmann C

Bachman HM, Roller E, Vu Tran Z, Henthorn TK

 

 

Abstract

Purpose            The purpose of this survey was to determine the prevalence and outcome of propofol abuse in academic anesthesia departments with residency training programs in the USA.

Background            Propofol is used extensively for induction of general anesthesia. It is not commonly considered a drug of abuse but propofol increases dopamine in brain areas thought to be associated with reward. This is the mechanism by which alcohol and other drugs are believed to reinforce substance abuse. Propofol has been reported to produce euphoria and there are case reports of abuse in anesthesia personnel.

A wide ranging survey of multiple drugs of abuse conducted in academic anesthesia programs during the 1990s reported two cases of propofol abuse in 11,666 individuals. The calculated 10-year incidence of propofol abuse was 0.02%.

Methodology            A primary survey was emailed to the chairperson of 126 anesthesia departments with residency programs in the USA. A second round of primary surveys was sent to those who did not respond to the first distribution. This was followed up with personal emails and phone calls. A secondary survey was sent to departments that reported any cases of propofol abuse. The secondary survey sought specific information about propofol abuse incidents. The denominator in incidence calculations was 23,385. This number was derived from the number of attending physicians and residents in residency programs. The number of certified registered nurse anesthetists (CRNAs) in departments with residency programs was estimated by assuming 20 CRNAs per program.

Result            Of the 126 primary surveys sent out in the first round there were 67 responses (53%). The second round yielded an additional 26 responses (21%). The response rate after two rounds was 74%. Phone calls and personal emails continue until the total response rate was 100%.

Twenty-five of 126 departments (20%) reported that one or more individuals had abused propofol in the previous 10 years. Two departments reported more than one incident. Seven deaths were reported, six residents and one anesthesia technician. Other drugs in addition to propofol may well have contributed to these deaths. The incidence of death reported to the survey was 28%. The incidence of death reported in residents reported to have abused propofol was 38%. The overall incidence of propofol abuse reported was 0.10%. (This incidence uses a denominator that was partially estimated.) This incidence was five times higher than the previous study but is still a tenth or less the incidence of other drugs of abuse.

Propofol was controlled by the pharmacy at 29% of the institutions represented in the survey and uncontrolled in 71%. Three of the 25 (12%) programs that reported propofol abuse had pharmacy control of propofol. Lack of pharmacy control of propofol was associated with propofol abuse (P=0.048).

Conclusion            Propofol abuse has become a growing problem in academic anesthesia programs. Pharmacy control of propofol should be considered.

 

Comment

The conclusions of this study concern me. While they may appear to be supported by the results of the survey, any support for them is weak at best.

The number of individuals reported to have abused propofol is based upon statements from chairs of academic departments only; it is not a sample of anesthesia providers in general. (It does not, for example, include any private practice anesthesia practices.) It is also an attestation by that chair and we don’t have any information about how chairs decided upon the number of cases of abuse that they reported. Their report may or may not be a valid number. Next, this report of propofol abuse cases was divided by the total number of anesthesia personnel and that number was partially estimated. As a result, the incidence calculated is, at best, an estimate. The estimate may not be generalizable to all anesthesia providers. This estimated incidence is then compared with an incidence from an earlier survey that was conducted on a different population and looked at multiple drugs of abuse. I am skeptical that these two studies are comparable enough to yield a valid comparison of the incidence of propofol abuse over time, as the authors intend. Using this information to reach the conclusion that propofol abuse is increasing in frequency is too much of a stretch for me.

I can only imagine that the recommendation to control propofol in the same way we control opioids was made by people who don’t have to work in the OR putting patients to sleep every day. It is difficult to imagine how adding paperwork and adding to the workload of pharmacists and anesthesia providers would reduce the incidence of propofol abuse to a meaningful extent. A number of other drugs that are controlled by pharmacy and are used in much smaller quantities have much higher incidences of abuse. The, so called, association between departments that didn’t control their propofol and the rates of propofol abuse is equally unimpressive. It certainly comes as no surprise that propofol abuse can be associated with departments that don’t control it when almost no department controls access to propofol.

It is tragic that a number of individual died abusing anesthetic drugs. Efforts to better understand the incidence, what leads individuals to abuse anesthetic drugs, who is likely to abuse anesthetic drugs, and how to intervene in a meaningful way are worthwhile. This survey may provide us with an estimate of the incidence of propofol abuse in academic anesthesia departments. I caution against using it for any other purposes.

 

Michael Fiedler, PhD, CRNA