significant hypotension, decreased cardiac output [168], and respiratory depression [169]. Continuous infusion with propofol results in a more rapid recovery than similar infusions with midazolam [170]. Patientcontrolled sedation with propofol has also been shown to be safe and effective [171].

Barbiturate sedative-hypnotic agents such as thiopental and methohexital, while older, still play a role in many clinical settings. In particular, methohexital, with controlled boluses (10–20 mg i.v.) or limited infusions remains a safe and effective sedative-hypnotic alternative with rapid recovery. However, with prolonged administration, recovery from methohexital may be delayed compared to propofol [172].

Ketamine, a phencyclidine derivative, is a unique agent because of its combined sedative and analgesic effects and the absence of cardiovascular depression in healthy patients [173]. Because the CNS effects of ketamine result in a state similar to catatonia, the resulting anesthesia is often described as dissociative anesthesia. Although gag and cough reflexes are more predictably maintained with ketamine, emesis and pulmonary aspiration of gastric contents is still possible [174]. Unfortunately, a significant number of patients suffer distressing postoperative psychomimetic reactions [175]. While concomitant administration of benzodiazepines attenuates these reactions, the postoperative psychological sequelae limit the usefulness of ketamine for most elective outpatient surgeries.

Droperidol, a butyrophenone and a derivative of haloperidol, acts as a sedative, hypnotic, and antiemetic medication. Rather than causing global CNS depression like barbiturates, droperidol causes more specific CNS changes similar to phenothiazines. For this reason, the cataleptic state caused by droperidol is referred to as neuroleptic anesthesia [176]. Droperidol has been used effectively in combination with various narcotic medications. While droperidol has minimal effect on respiratory function if used as a single agent, when combined with narcotic medication, a predictable dosedependent respiratory depression may be anticipated [177]. Psychomimetic reactions such as dysphoria or hallucinations are frequent, unpleasant side effects of droperidol. Benzodiazepines or narcotics reduce the incidence of these unpleasant side effects [178, 179]. Extrapyramidal reactions such as dyskinesias, torticollis, or oculogyric spasms may also occur, even with small doses of droperidol. Diphenhydramine usually reverses these complications [179]. Hypotension may

occur as a consequence of droperidol’s alpha-adrener- gic receptor blocking characteristics. One rare complication of droperidol is the neurolept malignant syndrome (NMS) [180], a condition very similar to malignant hyperthermia, characterized by extreme temperature elevations and rhabdomyolysis. The treatment of NMS and malignant hyperthermia is essentially the same. While droperidol has been used for years without appreciable myocardial depression [178], a surprising announcement from the Federal Drug Administration warned of sudden cardiac death resulting after the administration of standard, clinically useful doses [181]. Unfortunately, this potential complication makes the routine use of this once very useful medication difficult to justify given the presence of other alternative medications.

Butorphanol, buprenorphine, and nalbuphine are three synthetically derived opiates which share the properties of being mixed agonist-antagonists at the opiate receptors. These medications are sometimes preferred as supplemental analgesics during local, regional, or general anesthesia, because they partially reverse the analgesic and respiratory depressant effects of other narcotics. While these medications result in respiratory depression at lower doses, a ceiling effect occurs at higher dose, thereby limiting the respiratory depression. Still, respiratory arrest is possible, especially if these medications are combined with other medications with respiratory depressant properties [182]. While the duration of action of Butarphanol is 2–3 h, nalbuphine has a duration of action of about 3–6 h and buprenorphan up to 10 h, making these medications less suitable for surgeries of shorter duration. Table 6.6 summarizes the recommended doses for SAM.

6.5.3 Regional Anesthesia

Many limited cosmetic procedures may be performed using regional anesthesia, which is blockade of one or more sensory nerves with local anesthesia. Even though patients receive regional anesthesia, additional sedative analgesic medications can be administered.

6.5.4 General Anesthesia

Although significant advances have been made in the administration of local anesthetics, sedative-analgesic

medications, and regional anesthesia, the use of general anesthesia may still be the anesthesia technique of choice for many patients. General anesthesia is especially appropriate when working with patients suffering extreme anxiety, high tolerance to narcotic or sedative medications, or if the surgery is particularly complex. The goals of a general anesthetic are a smooth induction, a prompt recovery, and minimal side effects, such as nausea, vomiting, or sore throat. The inhalation anesthetic agents, halothane, isoflurane, and enflurane, have been widely popular because of the safety, reliability, and convenience of use. The newer inhalation agents, sevoflurane and desflurane, share similar properties with the added benefit of prompt emergence [186, 187]. Nitrous oxide, a longtime favorite anesthetic inhalation agent, may be associated with postoperative nausea and vomiting [188]. Patients receiving nitrous oxide also have a greater risk of perioperative hypoxemia.

The development of potent, short-acting sedative, opiates analgesics, and muscle relaxant medications has resulted in newer medication regimen that permits the use of intravenous agents exclusively. The same medications that have been discussed for SAM can also be used during general anesthesia as sole agents or in combination with the inhalation agents [189]. The anesthesiologist or CRNA should preferentially be responsible for the administration and monitoring of a general anesthesia.

Airway control is a key element in the management of the patient under general anesthesia. Maintaining a patent airway, ensuring adequate ventilation, and prevention of aspiration of gastric contents are the goals of successful airway management. For shorter cases, the airway may be supported by an oropharyngeal airway and gas mixtures delivered by an occlusive mask. For longer or more complex cases, or if additional facial surgery is planned requiring surgical field

avoidance, then the airway may be secured using laryngeal mask anesthesia (LMA) or endotracheal intubation [190].

Orthognathic surgeries that require unrestricted access to the oral and lower facial regions often require nasotracheal intubation. Obviously, this procedure requires an anesthesiologist with extensive training and experience to avoid serious complications to the upper airway. Techniques that facilitate nasotracheal intubation are listed in Table 6.7. Preflexing the tip of the endotracheal tube immediately prior to intubation that facilitates the passage of the tube around the nasopharyngeal junction is one helpful technique. When these precautions are followed, complications related to nasotracheal intubation, such as perioperative nasopharyngeal bleeding, or nasopharyngeal trauma are extremely rare (unpublished data from The Center for Oral and Facial Reconstruction and Reconstruction and Ambulatory Services, Irvine, CA).

6.5.5 Preoperative Preparation

Generally, medications which may have been required to stabilize the patient’s medical conditions, should be continued up to the time of surgery. Notable exceptions include anticoagulant medications, monoamine oxidase inhibitors (MAO) [191, 192], and possibly the angiotensin converting enzyme (ACE) inhibitor medications [80, 193]. It is generally accepted that MAO

Table 6.7 Techniques to facilitate nasotracheal intubation

Pretreating of the nasopharynx with vasoconstrictor (oxymetazoline 0.05%).

Nasotracheal tube one size smaller than the size normally used for orotracheal intubation.

Prewarming the endotracheal tube to 45°C

Progressively dilating the nasopharynx with lubricated rubber nasopharyngeal tubes after induction

Copious lubrication of the endotracheal tube with a dental anesthetic lubricant (with benzocaine 10%)

Preflexing the tip of the endotracheal tube just prior to intubation to negotiate the nasopharynx

Using curved intubating forceps to direct the endotracheal tube through the larynx

Presented at the Winter Medical Conference of Chapman Medical Center, 2005, Salt Lake City, UT

inhibitors, carboxazial (Marplan), deprenyl (Eldepryl), paragyline (Eutonyl), phenelzine (Nardil), tranylcypromine (Parnate), be discontinued 2–3 weeks prior to surgery, especially for elective cases, because of the interactions with narcotic medication, specifically hyperpyrexia, and certain vasopressor agents, specifically, ephedrine [191, 192]. Patients taking ACE inhibitors (captopril, enalapril, and lisinopril) may have a greater risk for hypotension during general anesthesia [80]. As previously discussed, diabetics may require a reduction in dosage of their medication. However, if the risks of discontinuing any of these medications outweigh the benefits of the proposed elective surgery, the patient and physician may decide to postpone, modify, or cancel the proposed surgery.

Previous requirements of complete preoperative fasting for 10–16 h are considered unnecessary by many anesthesiologists [194, 195]. More recent investigations have demonstrated that gastric volume may be less 2 h after oral intake of 8 oz of clear liquid than after more prolonged fasting [196]. Furthermore, prolonged fasting may increase the risk of hypoglycemia [197]. Many patients appreciate an 8 oz feeding of their favorite caffeinated elixir 2 h prior to surgery. Preoperative sedative medications may also be taken with a small amount of water or juice. Abstinence from solid food ingestion for 10–12 h prior to surgery is still recommended. Liquids taken prior to surgery must be clear [198], for example, coffee without cream or juice without pulp.

Healthy outpatients are no longer considered to be at higher risk for gastric acid aspiration and therefore, routine use of antacids, histamine type-2 (H2) antagonists, or gastrokinetic medications is not indicated. However, patients with marked obesity, hiatal hernia, or diabetes mellitus have higher risks for aspiration. These patients may benefit from selected prophylactic treatment [199]. Sodium citrate, an orally administered, non-particulate antacid, rapidly increases gastric pH. However, its unpleasant taste and short duration of action limits its usefulness in elective surgery [200]. Gastric volume and pH may be effectively reduced by H2 receptor antagonists. Cimetidine (300 mg p.o., 1–2 h prior to surgery) reduces gastric volume and pH. However, cimetidine is also a potent cytochrome oxidase inhibitor and may increase the risk of reactions to lidocaine during tumescent anesthesia [201]. Ranitidine (150–300 mg 90–120 min prior to surgery) [202], or famotidine (20 mg p.o. 60 min prior to surgery) are

equally effective but have a better safety profile than cimetidine [203].

Omeprazole, which decreases gastric acid secretion by inhibiting the proton pump mechanism of the gastric mucosa, may prove to be a safe and effective alternative to the H2 receptor antagonists [203]. Metaclopramide (10–20 mg p.o. or i.v.), a gastrokinetic agent, which increases gastric motility and lower esophageal sphincter tone, may be effective in patients with reduced gastric motility, such as diabetics or patients receiving opiates. However, extrapyramidal side effects limit the routine use of the medication [164, 204].

Postoperative nausea and vomiting (PONV) remains one of the more vexing complications of anesthesia and surgery [205]. In fact, patients dread PONV more than any other complication, even post operative pain [206]. PONV is the most common postoperative complication [207, 208], and the common cause of postoperative patient dissatisfaction [209]. Strategies to reduce PONV should be incorporated into the preoperative planning stages especially in patients with previous histories of PONV. Use of prophylactic antiemetic medication has been shown to reduce the incidence of PONV [210]. Even though many patients do not suffer PONV in the recovery period after ambulatory anesthesia, greater than 35% of patients develop PONV after discharge [211].

Droperidol, 0.625–1.25 mg i.v., is an extremely costeffective antiemetic [212]. However, troublesome side effects such as sedation, dysphoria, extrapyramidal reactions [179], and more recently, cardiac arrest have been described [181]. These complications may preclude the widespread use of droperidol altogether. The serotonin antagonists, ondansetron (4–8 mg i.v.), dolasetron (12.5 mg i.v.), and granisetron (1 mg i.v.) are among the most effective antiemetic medications available without sedative, dysphoric, or extrapyramidal sequelae [213–215]. The antiemetic effects of ondansetron may reduce PONV for up to 24 h postoperatively [216]. The Effects of ondansetron may be augmented by the addition of dexamethasone (4–8 mg) [217], or droperidol (1.25 mg i.v.) [218]. Despite the efficacy of the newer serotonin antagonists, cost remains a prohibitive factor in the routine prophylactic use of these medications, especially in the office setting.

Promethazine (12.5–25 mg p.o., p.r., or i.m.), and chlorpromazine (5–10 mg p.o., or i.m. and 25 mg p.r.), are two older phenothiazines, which are still used by

many physicians as prophylaxis, especially in combination with narcotic analgesics. Once again, sedation and extrapyramidal effects may complicate the routine prophylactic use of these medications [164].

Preoperative atropine (0.4 mg i.m.), glycopyrrolate (0.2 mg i.m.), and scopolamine (0.2 mg i.m.), anticholinergic agents, once considered standard preoperative medication because of their vagolytic and antisialogic effects, are no longer popular because of side effects such as dry mouth, dizziness, tachycardia, and disorientation [219]. Transdermal scopolamine, applied 90 min prior to surgery, effectively reduces PONV. However, the incidence of dry mouth and drowsiness is high [220], and toxic psychosis is a rare complication [221]. Antihistamines, such as diphenhydramine (25–50 mg p.o., i.m., or i.v.), and hydroxyzine (50 mg p.o. or i.m.), may also be used to treat and prevent PONV with few side effects except for possible postoperative sedation [222].

The selection of anesthetic agents may also play a major role in PONV. The direct antiemetic actions of propofol have been clearly demonstrated [223]. Anesthetic regimen utilizing propofol, alone or in combination with other medications, are associated with significantly less PONV [224]. Although still controversial, nitrous oxide is considered by many authors, a prime suspect among possible causes of PONV [188, 225, 226]. Opiates are also considered culprits in the development of PONV and the delay of discharge after outpatient surgery [164, 227–229]. Adequate fluid hydration has been shown to reduce PONV [230].

One goal of preoperative preparation is to reduce patients’ anxiety. Many simple, non-pharmacological techniques may be extremely effective in reassuring both patients and families, starting with a relaxed, friendly atmosphere and a professional, caring, and attentive office staff. With proper preoperative preparation, pharmacological interventions may not even be necessary. However, a variety of oral and parenteral anxiolytic-sedative medications are frequently called upon to provide a smooth transition to the operative room. Diazepam (5–10 mg p.o.), given 1–2 h preoperatively, is a very effective medication, which usually does not prolong recovery time [231]. Parenteral diazepam (5–10 mg i.v. or i.m.), may also be given immediately preoperatively. However, because of a long elimination half-life of 24–48 h, and active metabolites with elimination half-life of 50–120 h, caution must be