ambulatory anesthesia

Saeid Safari, MD

Department of Anesthesiology

Tehran University of Medical Sciences, Tehran, Iran

Ambulatory Anesthesia

Chapter 78, Miller 2010

Patient Selection Criteria

Patient Selection Criteria

• Selection of Procedures

• Duration of Surgery

• Patient Characteristics

• Susceptibility to Malignant Hyperthermia

• Extremes of Age

• Contraindications to Outpatient Surgery

Selection of Procedures

• Minimal postoperative physiologic disturbances and an

uncomplicated recovery.

• The primary predictors of prolonged stay or unanticipated

admission after day-case surgery are related to the type of

surgical procedure and associated complications (e.g., blood loss,

incisional pain, postoperative nausea and vomiting [PONV])

Specialty Types of Surgical Procedures

Dental • Extraction, restoration, facial fractures

Dermatology • Excision of skin lesions

General• Biopsy, endoscopy, excision of masses, hemorrhoidectomy, herniorrhaphy,

laparoscopic cholecystectomy, adrenalectomy, splenectomy, varicose vein surgery

Gynecology • Cone biopsy, dilatation and curettage, hysteroscopy, diagnostic laparoscopy, laparoscopic tubal ligations, uterine polypectomy, vaginal hysterectomy

Ophthalmology • Cataract extraction, chalazion excision, nasolacrimal duct probing, strabismus repair, tonometry

Orthopedic• Anterior cruciate repair, knee arthroscopy, shoulder reconstructions,

bunionectomy, carpal tunnel release, closed reduction, hardware removal, manipulation under anesthesia and minimally invasive hip replacements

Otolaryngology • Adenoidectomy, laryngoscopy, mastoidectomy, myringotomy, polypectomy, rhinoplasty, tonsillectomy, tympanoplasty

Pain clinic • Chemical sympathectomy, epidural injection, nerve blocks

Plastic surgery• Basal cell cancer excision, cleft lip repair, liposuction, mammoplasty

(reductions and augmentations), otoplasty, scar revision, septorhinoplasty, skin graft

Urology • Bladder surgery, circumcision, cystoscopy, lithotripsy, orchiectomy, prostate biopsy, vasovasostomy, laparoscopic nephrectomy and prostatectomy

More ideally suited to a 23-hour stay:

• Major postoperative surgical complications

• Major fluid shifts Autologous blood transfusions

• Lengthy procedures associated with excessive fluid shifts,

• Requiring prolonged immobilization and

• parenteral opioid analgesic therapy

Duration of surgery

• Was originally limited to procedures lasting less than 90 minutes

• Now, Surgical procedures lasting 3 to 4 hours are performed on

an ambulatory basis.

Patient Characteristics

• Originally, the majority of patients were classified as ASA physical

status I or II.

• Patients with preexisting medical conditions do not have an

increased incidence of perioperative complications or unexpected

admissions

• The risk can be minimized if preexisting medical conditions are

stable for at least 3 months before the scheduled operation.

Patient Characteristics

The ASA should not be considered in isolation

Because these factors can also influence decisions making:

1. Surgical procedure,

2. Anesthetic technique,

3. A Multitude of medical and social factors

So…

• Even morbid obesity (body mass index >40 kg/m2) is no longer

considered an exclusionary criterion for day-case surgery.

• The presence of obstructive sleep apnea syndrome was not

associated with an increased risk of unanticipated admission to

the hospital.

Susceptibility to Malignant Hyperthermia

• Managed with nontriggering anesthetics (e.g., local anesthesia).

• Admission solely on the basis of MH susceptibility is no longer

considered appropriate, and it should be based on clinical criteria

• If the anesthesia and surgery were uneventful, MH-susceptible

patients can be safely discharged home on the day of surgery.

Extremes of Age

• Even the “elderly elderly” patient (>100 years) should not be

denied ambulatory surgery solely on the basis of age.

• Most studies suggest that the risk is greatest in premature infants

younger than 46 weeks’ postconceptual age.

• The risk of apnea may persist until the 60th postconceptual week

and when anemia (hematocrit < 30%) exists.

Contraindications:

1. Potentially life-threatening chronic illnesses (e.g., brittle diabetes, unstable

angina, symptomatic asthma)

2. Morbid obesity complicated by symptomatic cardiorespiratory problems (e.g.,

angina, asthma)

3. Multiple chronic centrally active drug therapies (e.g., use of monoamine

oxidase inhibitors such as pargyline and tranylcypromine) and/or active

cocaine abuse

4. Ex-premature infants less than 60 weeks’ postconceptual age requiring

general endotracheal anesthesia

5. No responsible adult at home to care for the patient on the evening after

surgery

Preoperative Assessment

Preoperative Assessment

• Preoperative Evaluation

• Preoperative Preparation:

1. Nonpharmacologic Preparation

2. Pharmacologic Preparation

Preoperative Evaluation

• For outpatients undergoing superficial surgical procedures no

laboratory tests appear to be indicated in males, and only a

hemoglobin (or hematocrit) test is indicated for adult females of

child-bearing age.

• Obviously, patients with chronic diseases (e.g., hypertension,

diabetes) require additional laboratory studies (e.g., electrolytes,

glucose).


• Patients with an unexplained hemoglobin concentration of less

than 10 g/dL should be considered for further evaluation

• Eliminating routine preoperative testing (even in elderly

outpatients) will allow cost savings without compromising the

safety or the quality of patient care.


• Preoperative assessment 1 to 2 weeks before surgery was found

to reduce preoperative anxiety.

• Appropriate patient preparation before the day of surgery can

prevent:

1. Unnecessary delays,

2. Absences (“no shows”),

3. Last-minute cancellations,

4. Substandard perioperative care.

The preparation process is aimed at :

1. Reducing the risks inherent in ambulatory surgery,

2. Improving patient outcome,

3. Making the surgical experience more pleasant for the

patient and their family.

• Patients should be encouraged to continue all their chronic

medications up to the time that they arrive at the surgery center.

Nonpharmacologic Preparation

• High levels of stress preoperatively are associated with slower

recovery and greater analgesic and antiemetic requirements after

surgery, but it can be effectively reduced by careful preoperative

preparation

• Well-informed patients tend to recover faster and experience less

pain and fewer postoperative complications.

Preoperative psychological preparation reduces stress before and up to 1 week after surgery

Nonpharmacologic preparation

• Anesthetist's preoperative visit

• Preoperative educational programs

• Timing of the preoperative interview

• Instructional preoperative videotapes

• Self-hypnotic relaxation techniques

• Play-oriented preoperative teaching, books, pamphlets, and video

Pediatric patients

Pharmacologic Preparation

• Prospective studies have not found recovery to be prolonged after

the use of appropriate doses of sedative premedication in the

outpatient setting (e.g., midazolam, 1-2 mg intravenously [IV]

• Midazolam premedication not only decreases preoperative

anxiety but may also be associated with a reduction in

postoperative pain.

Pharmacologic Preparation:

1. Anxiolysis and Sedation

2. Preemptive (Preventative) Analgesia

3. Prevention of Nausea and Vomiting

4. Prevention of Aspiration Pneumonitis

Anxiolysis and Sedation:

• The most widely used premedicants have been barbiturates and

benzodiazepines.

• Methohexital and ketamine have been used for rectal

premedication in children.

• Melatonin produces sedation and anxiolysis comparable to oral

midazolam when administered for premedication


• Benzodiazepines,

• -α Adrenergic Agonists

• -β Blockers

Dosage Range Onset (min) Key Points

B e n z o d i a z e p i n e s

Midazolam

7.5-15 mg PO 15-30 Large first-pass effect

5-7 mg IM 15-30 Water soluble, nonirritating

1-2 mg IV 1-53 Rapid onset, excellent amnesia

Diazepam 5-10 mg PO 45-90 Long-acting metabolites

Temazepam 15-30 mg PO 15-40 Comparable anxiolysis to midazolam

Triazolam 0.125-0.25 mg PO 15-30 Prominent sedation

Lorazepam 1-2 mg PO 45-90 Prolonged amnestic effect

2 -α A d r e n e r g i c A g o n i s t s

Clonidine 0.1-0.3 mg PO 45-60 Prolonged sedative effect

Dexmedetomidine

50-70 µg IM 20-60 Bradycardia and hypotension

50 µg IV 5-30 Reduced anesthetic/analgesic requirements


• Temazepam and alprazolam also are effective oral premedicants

for outpatient surgery.

• Lorazepam, because of its long duration of amnesia, is not

recommended in the ambulatory setting.

• After admission to the day surgery center, intravenous midazolam

(1-3 mg IV) is the most useful drug.


• Oral clonidine, the prototypical 2-agonist, has been successfully αused for ambulatory premedication and may reduce

intraoperative blood loss, as well as the anesthetic and analgesic

requirements.

• Dexmedetomidine is a more highly selective 2-agonist that has a αshorter duration of action than clonidine.

The role of β-adrenergic blockers

• Appears to be increasing in ambulatory surgery because of their

ability to control acute autonomic responses during surgery while

minimizing the need for opioid analgesics.

Preemptive (Preventative) Analgesia:

• Opioid (Narcotic) Analgesics,

• Nonopioid Analgesics


• Perioperative multimodal analgesia is helpful in facilitating a faster

emergence from anesthesia and an earlier discharge.

• Use of opioid analgesics for premedication is not recommended

unless the patient is experiencing acute pain

• Opioid premedication can increase the incidence of PONV and

urinary retention, which can contribute to a delayed discharge

after ambulatory surgery


• NSAIDs can facilitate early recovery, decrease side effects, and

reduce discharge times,

When administered as part of a balanced

(“multimodal”) analgesic technique in

combination with local anesthetics and

acetaminophen.


• Ketorolac, a parenterally active NSAID, was more effective than

acetaminophen with codeine in preventing pain after outpatient

procedures in children.

• Celecoxib (400 mg)

• Addition of dexamethasone to a COX-2 inhibitor

• Gabapentin

Prevention of Nausea and Vomiting

Patient-Related Factors

Age

Gender

Preexisting diseases (e.g., diabetes)History of motion sickness or postoperative nausea and vomiting

Smoking history

Level of anxiety

Intercurrent illness (e.g., viral infection, pancreatic disease)

Anesthesia-Related Factors

PremedicationOpioid analgesicsInduction and maintenance anestheticsReversal (antagonist) drugsGastric distentionInadequate hydrationResidual sympathectomy

Surgery-Related FactorsOperative procedureLength of surgeryBlood in the gastrointestinal tractForcing oral intakeOpioid analgesicsPremature ambulation (postural hypotension)Pain

Common Factors for PONV


1. Pharmacologic Techniques:

• Butyrophenones, (e.g. Droperidol )

• Phenothiazines, (Prochlorperazine)

• Anticholinergics, (transdermal scopolamine)

• Antihistamines, (Dimenhydrinate and hydroxyzine)

• Serotonin Antagonists, (Ondansetron, granisetron, dolasetron,

and palonsetron )

• Neurokinin-1 Antagonists


• Nonpharmacologic Techniques:

1. Acupuncture,

2. acupressure, and

3. transcutaneous electrical nerve stimulation

at the P-6 acupoint

Prevention of Aspiration Pneumonitis

• H2-Receptor Antagonists

• Proton Pump Inhibitors,

• NPO Guidelines,

Prevention of Aspiration Pneumonitis

• Premedication with the rapid-acting proton pump inhibitor

pantoprazole (40 mg IV) was less effective than use of ranitidine

(50 mg IV) in reducing gastric volume and increasing pH.

• Prolonged fasting does not guarantee an empty stomach at the

time of induction.

NPO Guidelines

• Recent studies have confirmed the importance of ensuring adequate

hydration.

• Importantly, adequate hydration is associated with a decreased

incidence of postoperative side effects, including:

1. Pain,

2. Dizziness,

3. Drowsiness,

4. Thirst,

5. Nausea

Preoperative hydration of 20-mL/kg versus 2-mL/kg decreases in postoperative morbidity in outpatients.

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ambulatory anesthesia

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