American Journal of Anesthesiology

Propofol-Ketamine Technique: Safety Through Simplicity

Letter to Editor:

I would like to respond to Dr. Rosenberg' editorial, Back to the Future (Am J Anesthesiol. 1999;26(2):63). I have been working exclusively in the field of office-based anesthesia since 1991; this hardly puts me in the same league as the Ralph Waters' Downtown Clinic, but it may lend some credence to my observations.

There are two fundamentally different approaches that one may take when attempting to provide safe anesthesia in remote (office) settings. One may seek to recreate the same environment one may already be comfortable with in a freestanding surgicenter ¾change the environment to, for example, incorporate an anesthesia machine, scavenging, dantrolene, fiberoptic larygnoscopic equipment, a recovery room with recovery-dedicated, trained personnel. Alternatively, one may adopt one's technique to deal with the existing environment¾that is, go with the flow to provide cost-effective, S.A.F.E. anesthesia(1).

I first began doing office anesthesia for a surgeon (double-boarded in ENT and plastic surgery) in his AAAAPSF (now AAAASF) -certified facility with double ceiling drop gases, an anesthesia machine, and ice maker, an inflatable boat, and dantrolene. This setup would have been adequate to safely perform cardiac bypass surgery. This was essentially a one-room surgicenter as opposed to the significantly more primitive conditions found in many office operatories. As my practice evolved to serve multiple, distinct office sites, the transportation of even a Narkomed compact seemed tedious at best. In addition to the expense of the dantrolene, even the slight risk of malignant hyperthermia (MH) seems difficult to justify in patients having surgery with no medical indication (eg, cosmetic surgery).

The medical liability carriers in California have specified the availability of oxygen, the means for delivering it via positive-pressure ventilation (ie, Ambu bag), and the availability of suction as the minimum equipment for insuring coverage when surgery is performed in remote (office) settings. The Harvard standards of monitoring, adapted by the ASA, call for NIABP, EKG, and SpO2 when intravenous sedation is employed. There is no need to reinvent the wheel. Although a great deal of energy had been recently generated about the availability of defibrillators, no reports have been filed on the Society for Office Based Anesthesia (SOBA) Web site Clinical Forum section of patients requiring defibrillation in the office setting, despite my challenge. Only recently, after millions of passenger miles, has the first report of an airline passenger requiring defibrillation appeared in the newspapers. Vigilance for the A,B,Cs is the most likely reason that this is not an issue in the office setting. Most of the offices in which I now provide anesthesia have achieved certification by either the AAAASF or AAAHA. They have crash carts and defibrillators.

Regarding your concern that little data is available on safety in office-based anesthesia, I have recently published a 5-year outcome study(2) of 1,264 patients having mostly plastic/cosmetic surgical procedures with room-air, spontaneous-ventilation (RASV) propofol-ketamine dissociative monitored anesthesia care (MAC). Approximately one third of this group had had previous postoperative nausea and vomiting (PONV) or hangover from previous anesthetic experiences. By avoiding the routine use of opioids, only seven patients (0.6%) experienced PONV with the propofol-ketamine technique. This outcome compares very favorably with recent reports of 8.3%3 and 15%4 using opioids and either ondansetron or ondansetron/droperidol combination prophylaxis. No metoclopramide, droperidol or ondansetron was used as prophylaxis in any patient in the 1264 case series, including the ones with prior PONV. There were no cardiac arrests, admissions to hospital for unmanageable postoperative pain or PONV, or 911 calls. Discharge times were an hour or less in most cases.

Surgery was accomplished (even for xiphoid-to-pubis muscle imbrication for classical abdominoplasties) with the same basic approach. After 0.2 mg IV glycopyrrolate, the patients were titrated off to sleep (loss of verbal response and lid reflex) with a dilute (5 mg/mL) propofol solution (via a 60-gtts/ml set) piggybacked into the most proximal port to the patient. In an effort to preserve spontaneous ventilation, the induction took place over a 2- to 10-minute interval. One this state of hypnosis was achieved, a 50-mg bolus IV dose of ketamine was administered, and the surgeon was informed that the patient would be ready for injection of local anesthesia in 2 minutes' time ("the 2-minute warning"). The surgeon was encouraged to inject as much of the operative field as was reasonable. Subsequent reinjections of previously distended tissue do not require more ketamine. Greater than 200 mg total of ketamine is counterproductive to rapid emergence and discharge from the office facility.

Propofol-ketamine technique was first published in 19935,6 in the plastic surgery literature but was largely unnoticed by the anesthesia community. No recall or hallucinations have been reported using ketamine in propofol-ketamine technique.

Another roadblock in the successful implementation of propofol-ketamine technique is the notion that the upper limit of safe lidocaine is 7 mg/kg with epinephrine.(7) For liposuction cases, Jeffery A. Klein, MD, a San Juan Capistrano, California, dermatologic cosmetic surgeon, has established lidocaine 35 mg/kg as safe (8) when used in the following solution: 1000 mL NSS with 500 mg lidocaine and 1 mg epinephrine. Up to 4000 ml of this solution can be safely injected in a typical 60-kg female patient over a 20- to 30-minute period to achieve the 35- mg/kg dose. To quote the author, "It is the inherent slow rate of absorption from fat that accounts for the safety of liposuction…using high doses of lidocaine"8. Additionally, my personal experience (unpublished data) in nearly 200 face-life cases has been that up to 17 mg/kg lidocaine with epinephrine while not exceeding a total of 1000 mg has been devoid of any stigmata of lidocaine toxicity. (ie, seizures, severe hypotension, AV dissociation on EKG intraoperatively, or patient complains of tinnitus or metallic taste on the tongue postoperatively).

With regard to the three cosmetic surgery deaths mentioned in your editorial, I have specific comment on each instance. The first mentioned was a liposuction death as a result of oversedation, and this can best be prevented by both the avoidance of routine opioid use and the implementation of routine bispectral index (BIS™; Aspect Medical Systems, Inc.) monitoring. I have used the BIS monitor since December 1997 and have recently published an abstract (9) demonstrating a statistically significant average reduction in propofol use by 20% or $24.93 using the BIS monitor. The device is simple to apply, is self-calibrating, and is very effective once the learning curve is completed. I believe that the routine use of the BIS monitor will become more commonplace in the future.

The liposuction death from fluid mismanagement happened near my geographic locality (Irvine, California). In this tragic case, a surgeon intimidated a young anesthesiologist into administering 2 mL of fluid for every ml of liposuction aspirated (9000 ml out meant 18,000 ml in), with predictable, fatal results. The surgeon in question was a hospital-privileged, board-certified plastic surgeon operating in a Medicare-certified office facility. Following the Medical Board of California (MBC) review, he lost his license for 3 years. The anesthesiologist lost his license for 1 year. Upon further review of national liposuction complications, the MBC has recommended not more than 5000 ml per liposuction session. The moratorium did not specify whether this was total aspirate or fat only.

As to the MH death in a breast augmentation patient, dantrolene or no, there is no justification for exposing this class of patient (elective cosmetic surgery) to any risk of MH when a suitable alternative exists in the propofol-ketamine technique. In the earlier-cited 5-year review article,2 80 breast augmentations, both above and below the pectoralis, were performed without need to convert to general anesthesia.

My concern for safety in the office setting led me to found an educational society, the Society for Office Anesthesiologist, or SOFA, in 1996, which subsequently merged with SOBA in 1998. Unabashedly, I have set out to proselytize for patient safety through the simplicity of propofol-ketamine technique. Even the seven patients who experienced PONV said they would readily have propofol-ketamine technique for subsequent surgery. Patients who have experienced PONV after discharge home have reported that they knew it was related to taking the hydrocodone/acetaminophen and not the anesthetic. The cosmetic surgery patient is the last patient who will try to spare the anesthesiologist's feelings if the anesthetic was in any way unsatisfactory. The patients have expressed universal satisfaction with the technique. Every anesthesiologist who has taken the leap of faith to try this approach has reported satisfaction with the technique. RASV propofol-ketamine dissociative MAC¾the future is here. Safety through simplicity.

Note: The author has no financial interest (board membership, stock, etc.) in Aspect Medical Systems, Inc., manufactures of the bispectral index (BIS) monitor.

Barry L. Friedberg, MD
Secretary, SOBA (www.soba.org)
Corona del Mar, California