Propofol Ketamine Anesthesia for Cosmetic Surgery in the Office Suite. Barry L. Friedberg, MD

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1 Propofol Ketamine Anesthesia for Cosmetic Surgery in the Office Suite Barry L. Friedberg, MD Before 1968, the operating room did not exist outside the four walls of the hospital for most anesthesiologists. The first free-standing ambulatory surgicenter (ASC) was created in Phoenix, Arizona, in This initiated an era in which operating rooms were no longer confined to the hospital setting. In the mid-1980s, the Society for Ambulatory Anesthesia (SAMBA) was formed as a result of the ASC movement. In the past two decades, this society has grown, and it is estimated that more than 60% of all surgery in the United States is currently done on an outpatient basis. However, not all outpatient facilities are of equal caliber. Although office practitioners such as Ralph M. Waters, MD, operated the Downtown Clinic in Sioux City, Iowa, in 1919, the modern era of office-based anesthesia for cosmetic surgery is considered to have begun in the mid-1970s. One of the pioneers of this enterprise was Charles A. Vinnik, MD, a Las Vegas plastic surgeon. Unable to secure dedicated professional anesthesia services, Vinnik developed the diazepam/ketamine technique, 1 which eliminated the hallucinatory side effects of ketamine by preceding the dissociative 2 dose of ketamine with hypnotic doses of incremental diazepam. Diazepam/ketamine is a nontriggering technique that eliminated the need for either an anesthesia machine or dantrolene to treat the rare syndrome of malignant hyperthermia. A recent American Society of Anesthesiologists (ASA) publication validated the nontriggering approach for office anesthesia as safe without an anesthesia machine. 3 While manufacturers continue to shrink the size of anesthesia machines, interoffice transport and scavenging requirements impose added burdens to the office anesthesiologist. Aside from these issues, it is difficult for me to justify any risk of malignant hyperthermia in a patient population having surgery without medical indication (i.e., elective cosmetic surgery). Vinnik s breakthrough discovery was published in the plastic surgery literature, where it lay unnoticed and unappreciated by the anesthesia community for over a decade. In December 1991, I attended a lecture by 39

2 40 Friedberg Vinnik in Newport Beach, California. This encounter led to a site visit in early March 1992 at Vinnik s office suite, which was followed by my first propofol and ketamine (PK) anesthetic on March 26, Although I was the first to publish an article in the American literature about propofol and ketamine, 4 I was not the first to suggest pairing these agents. Guit and colleagues initially proposed using propofol and ketamine together in They advocated using the propofol and ketamine in a fixed-dose mixture as a total intravenous anesthetic (TIVA). My PK technique 6 differs from that method as it is derived from Vinnik s diazepam/ketamine technique, wherein each drug is given separately for specific effect, as in monitored anesthesia care (MAC). Prior to my substitution of propofol for diazepam, there was no literature to support the hypothesis that hypnotic doses of propofol would block ketamine hallucinations 7 as effectively as did diazepam. Concerns for patient safety led Vinnik to be one of the founding members of the American Association for the Accreditation of Ambulatory (formerly Plastic ) Surgical Facilities (AAAASF). In an era in which states like Florida and California required office certification by CMS (formerly HFCA), AAAHC, or AAAASF, what differentiates office-based anesthesia from an ASC? It is anesthesia given in a physician s office, that has other patient care activities beyond surgical procedures. The patients are often direct-paying, well patients (ASA 1 or 2) undergoing elective cosmetic surgeries, which are relatively superficial procedures (even abdominoplasty is superficial because it is an extraperitoneal dissection). Although the atmosphere is considerably more relaxed in the office compared with the hospital or ASC, the office-based anesthesiologist may be held to a higher standard of care because a short-acting, fast-emerging (S.A.F.E.) 8 anesthetic must be coupled with minimal or no postoperative nausea and vomiting (PONV) or pain. Macario and colleagues 9 recently confirmed that the postoperative outcome most patients wished to avoid was PONV. Hospitalization for PONV or uncontrollable postoperative pain is not a practical option for many elective cosmetic surgery patients. A further differentiating point between office-based anesthesia and ASC is the absence of the customary dedicated postanesthesia care unit (PACU) with a dedicated, trained RN. While some office-based anesthesiologists bring their own post-anesthesia recovery (PAR) nurse (D. Barinholtz, personal communication), many rely on rapid emergence to minimize postoperative risk to the patient. Since the OR in an office often serves as Admitting as well as PAR, there can be no ignorance of anesthetic outcomes: a patient experiencing PONV is literally in one s face. A second case in the same office or one down the street will not get started if a patient does not emerge quickly, PONV- and pain-free. A discussion of the impact of the bispectral index (BIS) monitor (Aspect Medical Systems, Newton, MA) on decreasing emergence time follows later in this chapter.

3 Propofol Ketamine Anesthesia for Cosmetic Surgery in the Office Suite 41 The ideal anesthetic technique would be one that is simple and safe and gives the illusion of general anesthesia (i.e., the patient neither feels nor hears the surgery), and yet does not depend on reversal agents (like naloxone or flumazenil) to compensate for inadvertent overdosage or paradoxical reactions of polypharmacy antinausea medications (like the combination of ondansetron, droperidol, metoclopramide, and dexamethasone). I founded the Society for Office Anesthesiologists (SOFA) in 1995 in Corona del Mar, CA, as a vehicle to promulgate the awareness and use of the PK technique. In 1998, SOFA merged with the Chicago-based Society for Office-Based Anesthesia (SOBA), founded by Charles Laurito, MD, and others. Partly as a result of the efforts of SOFA and SOBA, the ASA and SAMBA now recognize that office-based anesthesia is a legitimate outpatient subspecialty separate from the ASC venue (Fig. 1). Monitoring Hypnosis With the Bispectral Index When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory variety; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science. William Thompson, knighted Lord Kelvin. Figure 1. Blepharoplasty performed in office-based setting (Photo by Marshall Garland, MD.)

4 42 Friedberg Oliver Wendell Holmes coined the word anesthesia to describe the insensibility patients experienced from ether, the first anesthetic drug to become popular in the United States. As drugs with more specific actions became commonplace like fentanyl, for analgesia, and propofol, for hypnosis it became recognized that anesthesia might be taken as the sum of hypnosis and analgesia. In 1996, the U.S. Food and Drug Administration approved the BIS monitor for use in measuring the hypnotic component of anesthesia. The BIS monitor is an extremely helpful addition to the cosmetic surgery suite. As a result of routinely monitoring the BIS, I was able to discharge an awake and alert patient 30 minutes postoperatively after a 9.5-hour surgery that featured 3 hours of liposuction and 6 hours of facial surgery. Needless to say, the surgeon and office staff were quite pleased not to have to remain in the office for an additional hour or two had the patient experienced prolonged emergence or PONV or pain. Additionally, the BIS monitor helped me make the diagnosis of lidocaine toxicity in a 100-kg, 72-year-old white male having upper blepharoplasty with rhytidectomy. The surgeon injected 200 ml of what he thought was 0.5% lidocaine with 1:200,000 epinephrine. About 45 minutes into the case, while the propofol was progressively titrated down to zero, the BIS inexorably drifted down to zero! At this point I told the surgeon that the patient was in danger. The error in lidocaine was then discovered. Two percent (a total of 4,000 mg) had been injected instead of what was thought to have been 1,000 mg. Shortly after the patient was intubated and the paramedics were called to transport the patient to the nearest hospital, the EKG began to widen and the blood pressure began to fall. The lidocaine level drawn on admission to the emergency room was 12 ng/l, the upper end of the toxic range. The patient was ventilated overnight and discharged the following day, neurologically intact. As of 2002, widespread adoption of this unprecedented technology has not been seen. Some blame may fairly be placed at the feet of the manufacturer. In their enthusiasm to promote this nascent technology, they seized upon the issue of prevention of intraoperative patient awareness before assembling the data to substantiate the claim. Many in the anesthesia establishment were disturbed by what appeared to be exploitation by the manufacturer of this very sensitive issue with the general public. Others in the anesthesia community have used this issue to sustain their Luddite opposition to new technology. Still others refuse to make the effort to go through the learning curve of 20 to 100 cases required to be able to successfully incorporate this new information into their practice. Needless to say, I encountered these types of objections 20 years ago when I introduced the noninvasive automated blood pressure device to my hospital. It is obvious that Lord Kelvin s quote is as much about the

5 Propofol Ketamine Anesthesia for Cosmetic Surgery in the Office Suite 43 value of temperature measurement in 1891 as it is about BIS monitoring today. Given time, though, the anesthesia community will grow to understand that BIS has been validated as a measure of a patient s level of hypnosis 10,11 and that it is a valuable tool in the operating room. Premedication From March 26, 1992, through March 26, 1997, I collected data on my patients premedication. During this era, midazolam was given as 2 mg IV for cases expected to last less than 2 to 3 hours and as 4 mg IV for cases of greater duration, in an attempt to reduce propofol requirements per the surgeons request to mitigate the cost of the propofol. Upon reviewing and publishing this 5-year experience in June 1997, 12 I concluded that there was no value in premedicating with midazolam to consistently demonstrate a good (2 mg) or better (4 mg midazolam) propofol-sparing effect. In 1997, Oxorn and colleagues 13 published an elegant level I study confirming my level III publication. 12 Because patients continued to ask for premedication, the search for a good alternative to midazolam led to the rediscovery of clonidine 200 mcg PO 30 to 60 minutes preoperatively. The reduction in propofol requirements was demonstrable 14 because of the addition of routine BIS monitoring, 15 and patients were pleased with the relaxation effect of decreasing their endogenous catecholamine levels (Table 1). Table 1. The PK RASV NOPA MAC Cookbook Premedication: Clonidine 200 mcg, rofecoxib 50 mg PO min Induction: Glycoprryolate 0.2 mg IV with 2 cc lidocaine Propofol: enter pts wt in kg, set pump for 250-mcg/kg bolus & 100-mcg/kg/min basal rate; bolus 1-6 x until clinical effect apparent. When BIS = 70 75, bolus 50 mg ketamine & tell the surgeon that he/she may inject in 2 3 min. If pt moves slightly, add 25 mg more ketamine and wait a bit; if pt moves quite a bit, add 50 mg more ketamine and wait another min. (80% of my last 500 cases were done with either one or two 50-mg doses of ketamine.) Maintenance: Titrate propofol to maintain BIS No more than a total of 200 mg ketamine and none in last 20 min. Patient movement with BIS means more local. Without the BIS to objectively demonstrate adequate propofol effect, one is hard put to insist on more local from the surgeon, who is typically yelling for more propofol. Only after two subsequent reinjections (three total) will I give a bit more ketamine. Emergence: Turn off the propofol! Recovery: Sometimes patients want more analgesia. I usually give 1,000 acetaminophen with or without diphenhydramine (Tylenol PM), depending on the patient s emotional state. PK = propofol ketamine; RASV = room air, spontaneous ventilation; NOPA = nonopioid, preemptive analgesia; MAC = monitored anesthesia care.

6 44 Friedberg Propofol Induction I administered glycopyrrolate in half of my first 50 PK cases. Not all patients who did not receive glycopyrrolate required suctioning for excessive oral secretions. Those who did require suctioning complained of sore throat postoperatively. I now inform patients to expect a dry mouth for several hours postoperatively, but that the dryness goes away by itself. After the initial 50 cases, all patients received glycopyrrolate 0.2 mg with 2 ml lidocaine prior to initiating the propofol. Traditionally, the anesthesiologist is trained to administer an induction dose of propofol as a milligram per kilogram bolus. This usually renders the patient unconscious and requires some type of airway maneuver. The office-based anesthesiologist will do well to reflect on the vastly different circumstances in which he or she is asked to provide anesthesia. Further, induction via bolus (alternatively known as push and pray ) deprives the office anesthesiologist of an opportunity to discern the qualitative nature of the given patient s individuality for drug requirement. Accurately, rather than rapidly, medicating patients on induction will yield valuable clues about individual susceptibility, enabling a more costeffective use of propofol as well as speeding the emergence from anesthesia and discharge from the office. For the rare patient that evidences stage II excitement with gradual induction, speeding the infusion deals with the problem. Another unforeseen byproduct of gradual induction is the positive feedback from patients, who regularly state that they enjoyed not having the feeling of being put out. This is a great value, as the practice of cosmetic surgery anesthesia is very much about patient satisfaction. Nonemergent care on essentially fit, normovolemic patients for superficial cosmetic surgery with nonvasodilating agents (i.e., propofol) may mean that the customary teaching that these patients are dry because of their overnight fast is suspect. It is, therefore, illogical to try to correct a nonexistent problem by administering 500 to 1,000 cc of IV lactated Ringer s solution. The result of this well-intentioned but misguided therapy is usually a distended bladder at the end of the case, with inadvertent voiding on the operating table, an unnecessary urethral catheterization, or demand for a quick trip to the bathroom on emergence. For the initial 25 PK cases, I used small boluses of propofol from a syringe to induce hypnosis. The syringe was replaced by a 50-mL bag of normal saline spiked with a 60-gtt/mL IV set piggybacked into the most proximal port of the main IV to the patient (deadspace 1 ml). Induction, defined as loss of verbal response and loss of lid reflex, took place over a 2- to 10-minute interval in an attempt to preserve spontaneous ventilation as well as masseter tone. Additionally, once the patient began to relax, as evidenced by a loss of facial muscle tone, the head was extended and rotated to the side to effect dual vectors of force on the genioglossus

7 Propofol Ketamine Anesthesia for Cosmetic Surgery in the Office Suite 45 muscle to spare the necessity of instrumenting the airway. Further noninvasive force of extension could be applied by placing either a 500- or 1,000-mL IV bag under the patient s shoulders. If the preceding two maneuvers were inadequate to maintain the airway, a lubricated #28, red rubber Rusch airway was placed in the nasopharynx. If the airway still remained inadequate, a #4 laryngeal mask airway was inserted. With the exception of the one lidocaine toxicity patient, this airway algorithm has eliminated intubation in a 10-year experience in 2,680 patients for 80 different surgeons. However, this does not mean that a functioning laryngoscope and #7 endotracheal tube were not always available, but merely that they were unnecessary to the routine conduct of PK anesthesia. Further refinements in the induction of PK came in 1997 with the addition of the BIS monitor. The BIS is a well-validated measure of the patient s level of hypnotic state from propofol. Titrating the propofol to a BIS of 70 to 75 has replaced the traditional signs of hallucination-blocking levels of propofol. It is interesting to note that when placing antidrying ointment in the eyes at a BIS of 70 to 75, the lid reflex remains intact. This suggests that the loss of verbal response and loss of lid reflex as reliable clinical signs of an hallucination-blocking level of propofol were deeper than necessary, which, in turn, suggests that excessive doses of propofol were used in the pre-bis era of PK technique. Doses in excess of necessary obviously prolong emergence and discharge. In 2002, a quantitative Harvard Clinical infusion pump (Harvard Clinical Tech, South Natick, MA) replaced the familiar 50-mL drip bag (Fig. 2). The settings include programming the patient s body weight in kilograms, selecting a 250-ug/kg bolus over 20 seconds with a base infusion rate of 100 ug/kg. Propofol induction is now described as 250 ug/kg/min repeated one to six times until a clinical/bis effect is noted. 16,17 Dissociation Upon achieving a BIS of 70 to 75 with the gradual propofol induction, a 50-mg dissociative dose of ketamine IV push is administered and the surgeon is told that local anesthetic injection may commence in 2 to 3 minutes. I reduce the 50-mg dose to 25 mg for the Asian-born Asian patient, but the response to the 25-mg dose is 80% to 85% in the Americanized Asian, Caucasian, or Hispanic patient. In 80% of my last 500 cases, adequate dissociative effect was obtained with either one or two 50-mg doses of ketamine. Aggregate doses of ketamine greater than 200 mg are not compatible with rapid emergence and discharge from the office surgical facility. Since reinjection of previously distended operative fields does not require additional ketamine, one may wonder under what cir-

8 46 Friedberg Figure 2. Anesthesia setup in office interior. (Photo by Marshall Garland, MD.) cumstances one would reasonably require additional ketamine. After two subsequent injections of the operative field (following the initial injection), I may inject an additional 25 to 50 mg ketamine, predicated on the degree of patient movement. Under no circumstances will more ketamine be given in the last 20 minutes of the case. One of the most beneficial points of incorporating the BIS monitor in the PK technique is the ability to reassure the surgeon that, when the patient moves and the BIS is 60 to 70, the movement is unlikely to be associated with awareness or recall and that the addition of more local anesthetic, not more propofol, will likely result in the cessation of extraneous patient movement. Herein lies the suggestion that one of the values of BIS monitoring may be surgeon management. Ketamine is not a fentanyl substitute but a dissociative agent that, when in effect, provides the surgeon with a 10- to 20-minute window of opportunity in which to inject the local anesthetic as a field block or nerve block for analgesia for the planned operative procedure in a motionless patient. This is an all-or-none effect, meaning that the patient either lies still or does not for the injection. A dissociative dose of ketamine blocks the NMDA receptors in the spinal cord and midbrain prior to the injection of local anesthetic and prevents the cascade of negative cerebral neurohumors that results from the input of noxious stimuli. The benefits

9 Propofol Ketamine Anesthesia for Cosmetic Surgery in the Office Suite 47 of pre-emptive analgesia become manifested in the immediate and shortterm postoperative recovery phases from the surgical insult. A recent editorial appeared denying the existence of pre-emptive analgesia. 18 However, the writer did not consider dissociative technique, but only the article on the meta-analysis of pre-emptive analgesia, 19 when he declared that there was no evidence for the existence of pre-emptive analgesia. The profoundness of the paradigm shift observed in PK patients is evidenced in the minimal postoperative pain present after having received a dissociative effect of ketamine prior to the injection of local anesthesia before the surgical incision. Measuring the hypnotic (70 to 75) level of propofol with the BIS makes ketamine a predictable agent. Once the operative site is injected, no further ketamine needs to be administered for reinjection on of the same site. Transmucosal injections are not as stimulating as transcutaneous ones. The last 500 cases in my 10-year log revealed that 40% were done with a single 50-mg ketamine dose, and another 40% were done using two 50-mg doses of ketamine. Maintenance The basal infusion rate is set at 100 ug/kg/min and adjusted up or down as needed to maintain the BIS between 60 and 70. It appears that 100 ug/kg/min is adequate for the majority of patients. Lidocaine No discussion of office-based anesthesia would be complete without developing some notion of what may constitute a safe level of total lidocaine for the elective cosmetic surgical patient. Tumescent liposuction is a very popular procedure. The Physician s Desk Reference (PDR) specifically states that the maximum safe dose of lidocaine with epinephrine 7 mg/kg, and no greater than a total of 500 mg. 20 Various advocates of tumescent liposuction have published that 35 mg/kg, mg/kg, 22 or even 90 mg/kg 23 is safe when diluted in a solution of 500 mg lidocaine, 1 mg epinephrine, and 1,000 ml normal saline. A spate of liposuction-related deaths in the late 1990s prompted the Florida legislature to enact a 4,000- ml total aspirate as the limit for office-based liposuction; California enacted a 5,000-mL total fat aspirate as a similar limit for the office setting. Since 80% of my patients are middle-aged females weighing an average of 60 kg, an equal volume of tumescent fluid to that extracted as limited in California would work out to a maximum of 83 mg/kg. In the absence of any stigmata of lidocaine toxicity, this dose appears to be well tolerated in healthy office-based surgical candidates for liposuction. Certainly factors like the removal of half of the injectate with the aspirate or the delayed

10 48 Friedberg absorption from the vessel-poor group, compounded by the vasoconstriction from the added epinephrine, as well as the elevation of the acute seizure threshold by BIS-measured hypnotic levels of propofol in patients with SpO 2 > 95% contribute to the safety of this practice. Injections for breast augmentation or rhytidectomy of up to 200 ml lidocaine 0.5% (1,000 mg) with epinephrine 1:200,000 have also been well tolerated in my published 14 and 10-year clinical experience. Extensive safe clinical experience strongly suggests that the PDR limitation is overly conservative and outdated. PONV and Opioids If you want to stop people being sick, don t give emetics. Its simplicity is so overwhelming that it goes over the heads of most anaesthetists, but not over those of patients nor, dare I say, surgeons. Chris Pollock, MB While there is an extensive compendium differential diagnosis of the causes of PONV, the true cause (routine opioid administration) is consistently ignored in the literature. I struggled with the belief system that all surgical patients benefit by some routine, judicious, use of opioids for the first 5 years of PK. I have eliminated opioids since December 1997 without inflicting undue postoperative suffering in my patients. PK anesthesia proposes that anesthesiologists remove themselves from the analgesia business and leave that to the surgeon s local analgesia. The cosmetic Table 2. Selective Cosmetic Surgeries Commonly performed cosmetic surgical procedures (all have successfully implemented PK technique): Rhinoplasty (closed or open) Liposuction or suction-assisted lipoplasty Blepharoplasty (open, transconjuctival, or endoscopic) Rhytidectomy (open or endoscopic 24 ) Breast augmentation, subglandular, subpectoral (via areaolar, transaxillary, or umbilical approach) Hair transplantation with or without scalp reduction Facial resurfacing (laser, chemical peel, or mechanical dermabrasion) Brow lift (coronoplasty or endoscopic 25 ) Abdominoplasty (classical or simple skin) Otoplasty Genioplasty (mandibular advancement or recession) Facial implants (malar and mandibular with silicone or autologous fat) Lip enlargement (autologous fat transfer, radiated cadaver material [Alloderm], or Gore-Tex extrusions) Platysma band plication

11 Propofol Ketamine Anesthesia for Cosmetic Surgery in the Office Suite 49 Table 3. Other Procedures Successfully Performed with PK Anesthesia Breast biopsy, lumpectomy, simple mastectomy Herniorrhaphy, inguinal or umbilical Arthroscopy, knee and other joints Gynecologic laparoscopy (tubal ligation and fulguration of endometrial implants) Lithotripsy surgical population is a high-risk group for PONV: approximately 35% of patients, when asked directly, admit to previous PONV, a high-risk marker for subsequent PONV. By eliminating opioids from PK, I obtained a total of 13 PONV experiences in 2,680 patients (0.05% PONV) having PK over a 10-year period without antiemetic prophylaxis. This strongly suggests that the nonopioid approach to analgesia would be a significant breakthrough in the elimination of the scourge of PONV. Critics complain about the lack of science without a level I study confirming this PONV experience. I answer this legitimate objection by saying that the point of a level I study is to ensure reproducibility. Every anesthesiologist I have heard from who has followed the nonopioid, hypnosis first, then dissociation plan has successfully reproduced my PONV rate while eliminating the hallucinatory side effects of ketamine. Conclusion Office-based anesthesia continues to grow with the demand for cosmetic surgery and other ambulatory procedures (Tables 2 and 3). Many published anesthetic techniques have been used in this vast and evolving field. Certain techniques are preferred when surgeons are reluctant to administer sufficient local anesthesia or hypotension is required for good results. The best anesthetic technique provides safety and comfort for the patient. For growing numbers of office-based anesthesiologists in Australia, Japan, Canada, the United States, and England dissatisfied with PONV rates from propofol opioid approaches, my PK technique is gaining favor. References 1. Vinnik CA. An intravenous dissociation technique for outpatient plastic surgery: tranquility in the office facility. Plast Reconstr Surg 1981;67: Pender JW. Dissociative anesthesia. JAMA 1971;215: Twersky RS. Office-Based Anesthesia: Considerations for Anesthesiologists in Setting Up and Maintaining a Safe Office Anesthesia Environment. American Society of Anesthesiologists, Park Ridge, IL, Friedberg BL. Ketamine as adjuvant for sedation with propofol [letter]. Society for Am-

12 50 Friedberg bulatory Anesthesia Newsletter. American Society of Anesthesiologists, Park Ridge, IL, 1992;7:10 5. Guit JBM, Koning HM, Coster ML, et al. Ketamine as analgesic for intravenous anesthesia with propofol (TIVA). Anaesthesia 1991;46: Friedberg BL. Propofol ketamine technique. Aesth Plast Surg 1993;17: Friedberg BL. Hypnotic doses of propofol block ketamine-induced hallucinations [letter]. Plast Reconstr Surg 1993;91: Apfelbaum JL, Graseala TH, Walawander CA. The S.A.F.E. study team: Bypassing the PACU: a new paradigm in ambulatory surgery [abstract]. Anesthesiol 1997;87:A32 9. Macario A, Weinger M, Carney K, et al. Which clinical anesthesia outcomes are important to avoid? The perspective of patients. Anesth Analg 1999;89: Glass PSA, Bloom M, Kearse L, et al. Bispectral analysis measures sedation and memory effects of propofol, midazolam, isoflurane and alfentanil in healthy volunteers. Anesthesiol 1997;86: Kearse LA, Rosow C, Zaslavsky A, et al. Bispectral analysis of the electroencephalogram predicts conscious processing of information during propofol hypnosis and sedation. Anesthesiol 1998;88: Friedberg BL. Propofol ketamine technique, dissociative anesthesia for office surgery: a five-year review of 1264 cases. Aesth Plast Surg 1999;23: Oxorn DC, Ferris LE, Harrington E. The effects of midazolam on propofol-induced anesthesia: propofol dose requirements, mood profiles and perioperative dreams. Anesth Analg 1997;85: Friedberg BL, Sigl JC. Clonidine premedication decreases propofol consumption during bispectral index (BIS)-monitored propofol ketamine technique for office-based surgery. Dermatol Surg 2000;26: Friedberg BI, Sigl JC. Bispectral index (BIS) monitoring decreases propofol usage during propofol ketamine office based anesthesia [abstract]. Anesth Analg 1999;88:S Aramov MN, Badrinath S, Shadrick M, et al. The effect of ketamine on EEG-bispectral index during propofol sedation. Anesthesiol 1997;87:A Friedberg BL. The effect of a dissociative dose of ketamine on the bispectral index (BIS) during propofol hypnosis. J Clin Anes 1999;11:4 18. Hogan QH. No pre-emptive analgesia. Is that so bad? Anesthesiol 2002;96: Moiniche S, Kehlet H, Dahl J. A qualitative and quantitative systematic review of preemptive analgesia for postoperative pain relief, the role of timing of analgesia. Anesthesiol 2002;96: Physician s Desk Reference: Xylocaine. Montvale, NJ: Medical Economics, 2002: Klein JA. Tumescent technique for regional anesthesia permits lidocaine doses of 35 mg/kg for liposuction. J Dermatol Oncol 1990;16: Ostad A, Kageyama N, Moy RL. Tumescent anesthesia with a lidocaine dose of 55 mg/kg is safe for liposuction. Dermatol Surg 1996;22: Lillis PJ. Liposuction surgery under local anesthesia: limited blood loss and minimal lidocaine absorption. J Dermatol Surg Oncol 1988;14: Isse NG. Endoscopic facial rejuvenation. Clin Plastic Surg 1997;24: Isse NG. Endoscopic facial rejuvenation: endoforehead, the functional lift. Aesth Plast Surg 1994;18:21