Surgical Procedures in the Office-Based Setting



Surgical Procedures in the Office-Based Setting


Jonathan D. Bernardini

Fred E. Shapiro



With the recent advances in modern medicine and medical technology, an increasing number of physicians are able to perform more advanced and complex surgical procedures in their offices. Although the list of these procedures continues to grow everyday, most of the surgical procedures performed in a doctor’s office involve some form of sedation and analgesia in order to lessen the pain and anxiety of the surgery. Regardless of whether it is a simple mole removal, breast augmentation and reduction, liposuction, hernia repair, or knee arthroscopy, a rapidly growing number of patients prefer to have these surgeries performed in a doctor’s office rather than in hospitals or ambulatory surgical centers. As we saw in Chapter 2, patients and surgeons make their choices based on issues of cost, convenience, and scheduling. When one looks at the statistics, it appears that over the next few years more complex procedures are likely to become commonplace. Indeed, some office-based procedures are of such degree of complexity that they involve general anesthesia (GA) to provide a total loss of consciousness in the surgical patient (1). This becomes an added burden to all health care providers involved; the desire to keep up with the trends and advances, yet maintain the traditional standard of providing a safe, pleasant, and comfortable experience for the patient.

According to the American Society of Anesthesiologists’ (ASA) Guidelines for Office-Based Anesthesia, it is estimated that in 2005, ten million procedures were performed in doctors’ offices—twice the number of office-based surgeries performed in 1995. Furthermore, while 80% of surgeries are currently performed in hospitals or ambulatory surgical centers, we are seeing the same trend in the movement to the office-based setting as we saw 20 years ago with the shift from the inpatient to the outpatient setting. Currently, approximately one out of ten surgeries are performed in a doctor’s office.

While it is nearly impossible to list the myriad surgical procedures performed in any number of subspecialist physician offices, this chapter will attempt to cover some of the more common procedures. Many of the office-based procedures would benefit equally from the available methods of anesthesia (i.e., local, regional, monitored anesthesia care [MAC], GA—see Chapter 7) and will vary from patient to patient depending on a number of situations and variables.










Table 11.1. Recommended doses of commonly used drugs in the operating room


















































































































































































Drug


Bolus Dose


Infusion Rate


Sedatives/Anxiolytics/



Amnestics



Lorazepam


0.02-0.08 mg/kg IV




0.05 mg/kg PO



Midazolam


0.02-0.1 mg/kg IV




0.5-0.75 mg/kg PO



Dexmedetomidine (α2 agonist)


1 μg/kg IV over 10-15 min


0.2-0.7 μg/kg/h


Intravenous



Anesthetics



Propofol


2-2.5 mg/kg IV


25-200 μg/kg/min



Etomidate


0.2-0.6 mg/kg IV



Methohexital


1-1.5 mg/kg IV (induction)


20-60 μg/kg/min




0.2-0.4 mg/kg IV (sedation)



Thiopental


3-5 mg/kg IV (induction)


30-200 μg/kg/min




0.5-1.5 mg/kg IV (sedation)



Ketamine


1-4 mg/kg IV (induction)


10-75 μg/kg/min




0.2-1 mg/kg IV (sedation)


Opiate Analgesics



Fentanyl


0.25-1 μg/kg IV
(25-100 μg/dose IV p.r.n.)



Remifentanil


0.5-1 μg/kg IV


0.025-2 μg/kg/min



Sufentanil


0.5-30 μg/kg IV


0.3-1.5 μg/kg/h




(10-50 μg IV p.r.n.)



Morphine


0.05-0.1 mg/kg IV


Nonopiate Analgesics



Ketorolac


15-30 mg IV


Inhaled Anesthetics



Nitrous oxide (inspired concentration)


30%-70%



Desflurane (MAC)


6.0



Sevoflurane (MAC)


2.05


Muscle Relaxants



Succinylcholine


1-1.5 mg/kg IV (intubation)



Cisatracurium


0.15-0.2 mg/kg IV (intubation)




0.03 mg/kg IV (maintenance)



Rocuronium


0.6-1.2 mg/kg IV (RSI)



Vecuronium


0.1 mg/kg IV (intubation)




0.01-0.02 mg/kg IV (maintenance)


Reversal Agents



Edrophonium (with atropine)


0.5-1.0 mg/kg IV



Neostigmine (with glycopyrrolate)


0.07 mg/kg IV, 5 mg max


Anticholinergics



Atropine


10-15 μg/kg



Glycopyrrolate


7-10 μg/kg


Antiemetics



Dolasetron


12.5 mg IV



Ondansetron


0.1 mg/kg IV, 4 mg max


MAC, monitored anesthesia care; RSI, rapid sequence induction.


Modified from: Sa Rego MM, Mehernoor FW, White PF. The changing role of monitored anesthesia care in the ambulatory setting. Anesth Analg. 1997;85:1020-1036, (2).



With office-based surgical procedures, as with hospital or ambulatory surgical center-based procedures, patients will need to undergo a detailed history and physical examination. All comorbidities, medications, including over-the-counter and herbal preparations, allergies, problems with previous anesthesia, and psychosocial details will need to be factored into the anesthetic plan. Finally, the anesthesiologist may decide that a patient’s comorbidities and other factors preclude him from a surgical procedure in an office setting.

When the decision has been made to proceed in the office setting, it is crucial to insure that all necessary monitors, airway adjuncts, anesthesia equipment, and other devices are present and that they are in good operating condition before beginning a procedure where any type of sedation or anesthesia will be administered.

Table 11.1 and Box 11.1 are essential items for the office-based setting. A comprehensive list can be found in Chapter 10. There will be individual variations based on the specific procedure, the facility, and the type of anesthesia planned.


COMMON COSMETIC SURGICAL PROCEDURES

The section that follows discusses the seven most common cosmetic surgical procedures including their anesthetic considerations and complications (see Box 11.2).




Liposuction

Liposuction is the most common cosmetic operation performed in the United States. It is the surgical removal of subcutaneous fat by means of aspiration cannulas, introduced through small skin incisions, assisted by suction. It is also referred to as liposuction surgery, suction-assisted lipectomy, suction lipoplasty, fat suction, blunt suction lipectomy, and liposculpture (3).


Procedure

The original technique developed in the 1970s has been modified and over the last decade has been enhanced by the subcutaneous infusion of crystalloid fluid containing local anesthetic and epinephrine. The resulting mixture of fat and infused wetting solution is aspirated through cannulas. Wetting solutions typically consist of 1 L (=1,000 mL) of Ringer’s lactate containing 0.25 to 1 mg of epinephrine and 200 to 1,000 mg of lidocaine (4,5). A concentration of epinephrine of 1 per 1,000,000 (1 mg/1 L) provides excellent vasoconstriction after 10 to 20 minutes before aspiration of the adipose tissue. The amount of lidocaine used depends primarily on the mode of anesthesia. Lower concentrations of lidocaine will provide adequate postoperative analgesia and can be used for patients receiving GA or regional anesthesia. Higher concentrations of lidocaine are used for patients undergoing local or MAC anesthesia. The choice of anesthetic depends on the surgical region, the extent of adipose resection, the length of the procedure, and patient preference (5).

Typically, 1 mL of wetting solution will be used for each 1 mL of anticipated adipose resection. More dramatic results can be achieved with large-volume liposuction (>5,000 mL) whereas more subtle results are achieved with small-volume liposuction (<5,000 mL) (5). Tumescent liposuction involves a fluid infusion of two to three times the volume of the anticipated adipose resection. This is a method of performing liposuction under local anesthesia and precludes the use of additional anesthetic medications at dosages that may cause loss of airway reflexes or suppression of respiratory drive (3).

More recent developments involve the use of ultrasound assisted liposuction (UAL) in which ultrasound waves are targeted on the area to be treated, and fat cells are disrupted which can then be removed in a similar manner as the Illouz technique. This is a technique that will be used in conjunction with conventional liposuction more frequently in the future.

The procedure may take 2 to 7 hours depending on the extent of surgical resection. Large-volume procedures may require postoperative hospitalization for patient monitoring and pain control. Pain is managed immediately following surgery with the use of intravenous narcotics followed by oral analgesics as an inpatient and after discharge. The area treated will be wrapped with compression dressings to minimize swelling and bruising, although moderate to severe bruising is not uncommon, especially in the first several postoperative days. Patients are encouraged to ambulate on the day following surgery, progressively increasing to regularly walking after 2 weeks with full resumption of activities after a minimum of 4 weeks.


Anesthetic Considerations

It is important to recognize that liposuction is not a trivial procedure; a clear and detailed medical history and physical examination are required to insure safe treatment and a successful outcome. Certain physical signs will
guide the surgeon and anesthesiologist in the assessment and suitability for surgery. Particular areas of the body should be approached with caution, notably the areas around the lower part of the buttock and the inner, outer, and posterior aspects of the thigh because of the risk of complications and contouring deformities.

Ideally, patients considering liposuction should be ASA category I or II, physically active, and have maintained a stable weight for 6 months to 1 year. The procedural techniques described in the preceding text have been developed to reduce blood loss and provide adequate postoperative analgesia. Intravenous fluids should be limited when performing large-volume procedures due to the large volumes of wetting solution utilized. Approximately two thirds of the wetting solution injected subcutaneously will be absorbed into the intravascular space. Conversely, larger volumes of intravenous fluids are required for small-volume liposuction to augment the small volumes of wetting solution (5).


Anesthetic Technique

In small-volume liposuction, adequate pain relief may be provided by the anesthetic infiltrate solutions alone or with a combination of local anesthetic and varying degrees of sedation. Large-volume cases typically require regional (spinal, epidural) or GA. Regional anesthesia has raised some concern regarding the associated vasodilation and the resulting potential for increased blood loss and fat embolization. GA allows for larger adipose resections and for the procedure to be done in all body regions while providing a greater degree of patient comfort (5).

Table 11.2 includes examples of typical general and MAC anesthetics for this and other appropriate surgical procedures (5).








Table 11.2. Examples of typical general and monitored anesthesia care anesthetics































































































General Anesthesia


MAC Anesthesia


Premedication


Midazolam 2 mg IV (in holding area) and



Midazolam 2 mg IV (in holding area)


Induction


0.25-1 mg IV during procedure titrated to effect



Propofol 2.0-2.5 mg/kg IV or



Thiopental 3-5 mg/kg IV or


O2 3-4 L/min by nasal cannula or 6-8 L/min by face mask with capnograph



± Fentanyl 1 μg/kg IV


Muscle Relaxation



Succinylcholine 1 mg/kg IV (for intubation)


Propofol 1-1.5 mg/kg IV then 50-100 μg/kg/min or



Vecuronium 0.1 mg/kg IV or


Dexmedetomidine 1 μg/kg for 15-20 min then 0.2-0.7 μg/kg/h or



Cisatracurium 0.2 mg/kg IV or



Rocuronium 0.6-1.2 mg/kg IV or


Remifentanil 0.25-0.75 μg/kg/min


Maintenance of Anesthesia


Fentanyl 12.5-25 μg IV can be titrated to effect and monitor for respiratory depression



O230%-100%



± N2O 0%-70% plus



Desflurane or sevoflurane


Reversal of muscle relaxation:



Neostigmine 0.07 mg/kg IV plus



Glycopyrrolate 0.01 mg/kg IV


Analgesia:



Fentanyl 25 μg IV titrated to effect up to 100 μg total



Morphine 1-4 mg IV titrated to effect up to 8 mg total



(Monitor for respiratory depression)


Nausea prophylaxis



Dolasetron 12.5 mg IV



± Metoclopramide 10 mg IV



Consider OG tube placement and suction for patients at risk for postoperative nausea and vomiting (PONV).


O2100%


Suction oropharynx


Extubate (based on standard extubation criteria)



OG, orogastric.


Modified from: Jaffe RA, Samuels SI. Anesthesiologist’s manual of surgical procedures, 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2004:114-137, 892-894, B1-B4.



For patients receiving GA, either an endotracheal tube (ETT) or laryngeal mask airway (LMA) can be used. Factors such as gastroesophageal reflux (GERD) and unusual patient positioning may preclude the use of an LMA. All patients should receive adequate intravenous access based on fluid requirements, anticipated blood loss, and potential for receiving blood products during the procedure. For most cosmetic surgery, an 18- or 20-gauge angiocatheter in either upper extremity should be sufficient, although each patient should be evaluated and managed independently.


Complication

Liposuction has the potential for complications from a number of different etiologies (see Box 11.3). Local anesthetic toxicity from the wetting solution is a concern; cardiac dysrhythmias and deaths related to this have been reported (6). Lidocaine dosages in the wetting solution of 35 to 55 mg per kg are generally accepted as safe and are routinely employed (3,4). Bupivacaine has not been studied for use in liposuction wetting solutions (5). Epinephrine doses should not exceed 0.07 mg per kg, although doses as high as 0.10 mg per kg have been used safely. Its use should be avoided in patients with pheochromocytoma, hyperthyroidism, severe hypertension, cardiac disease, and peripheral vascular disease (5).


Owing to the potentially large volumes of fluid utilized during this procedure, the potential for volume overload exists which can lead to heart failure and cardiogenic pulmonary edema. For example, the “tumescent technique” where 2 to 3 mL of wetting solution is infiltrated for every mL of anticipated lipoaspirate, leaves behind 50% to 70% of the infiltrated volume (5).
Conversely, large volume liposuction, in the absence of adequate fluid replacement, may result in moderate to severe hypovolemia and, possibly, shock. Although excessive blood loss was seen more commonly in the early days of liposuction before the use of tumescence, it continues to be of concern. Related to all of these concerns is the risk of hypothermia due to the large volumes of wetting solutions, which are not typically warmed. The rapid infusion of large volumes of relatively cold fluid can quickly lower body temperature to dangerous levels. Great care should be taken to vigorously maintain the patient’s body temperature using heated forced-air units and intravenous fluid warmers. Other complications include pulmonary embolism, fat emboli, peripheral nerve injury, and abdominal cavity perforation (5).

Longer-term risks are related to decreased mobility, particularly if surgery involved the legs or lower abdomen. The patient is at increased risk of developing a deep venous thrombosis (DVT), so prophylactic treatment of this condition may be necessary.

Finally, as is the case with all surgical procedures, there may be postoperative inflammation or infection resulting from tissue trauma. Preincisional prophylactic antibiotics are routinely used and greatly reduce these risks.


Augmentation Mammoplasty

There is documentation of an attempted breast augmentation performed in the late 19th century when a surgeon transplanted a lipoma from the back of a woman into her breasts. Various materials have been used over the years from liquid paraffin injections to gel implants to the permanent tissue expanders in current use.

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Jun 12, 2016 | Posted by in ANESTHESIA | Comments Off on Surgical Procedures in the Office-Based Setting

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