Ambulatory Anesthesia Chapter 78, Miller 2010

1. Saeid Safari, MD
Department of Anesthesiology
Tehran University of Medical Sciences, Tehran, Iran
Ambulatory Anesthesia
Chapter 78, Miller 2010

2. Patient Selection Criteria

3. Patient Selection Criteria
• Selection of Procedures
• Duration of Surgery
• Patient Characteristics
• Susceptibility to Malignant Hyperthermia
• Extremes of Age
• Contraindications to Outpatient Surgery

4. 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])

5. 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

6. 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

7. 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.

8. 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.

9. 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

10. 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.

11. 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.

12. 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.

13. 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

14. Preoperative Assessment

15. Preoperative Assessment
• Preoperative Evaluation
• Preoperative Preparation:
1. Nonpharmacologic Preparation
2. Pharmacologic Preparation

16. 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).

17. Preoperative Evaluation
• 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.

18. Preoperative Evaluation
• 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.

19. 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.

20. 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.

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

22. 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

23. 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.

24. Pharmacologic Preparation:
1. Anxiolysis and Sedation
2. Preemptive (Preventative) Analgesia
3. Prevention of Nausea and Vomiting
4. Prevention of Aspiration Pneumonitis

25. 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

26. Anxiolysis and Sedation:
• Benzodiazepines,
• α-Adrenergic Agonists
• β-Blockers

27. 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
α 2 - 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

28. Anxiolysis and Sedation:
• 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.

29. Anxiolysis and Sedation:
• Oral clonidine, the prototypical α2-agonist, has been successfully
used for ambulatory premedication and may reduce
intraoperative blood loss, as well as the anesthetic and analgesic
requirements.
• Dexmedetomidine is a more highly selective α2-agonist that has a
shorter duration of action than clonidine.

30. 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.

31. Preemptive (Preventative) Analgesia:
• Opioid (Narcotic) Analgesics,
• Nonopioid Analgesics

32. Preemptive (Preventative) Analgesia:
• 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

33. Preemptive (Preventative) Analgesia:
• 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.

34. Preemptive (Preventative) Analgesia:
• 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

35. Prevention of Nausea and Vomiting

36. 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
Premedication
Opioid analgesics
Induction and maintenance
anesthetics
Reversal (antagonist) drugs
Gastric distention
Inadequate hydration
Residual sympathectomy
Surgery-Related Factors
Operative procedure
Length of surgery
Blood in the gastrointestinal tract
Forcing oral intake
Opioid analgesics
Premature ambulation (postural
hypotension)
Pain

37. Prevention of Nausea and Vomiting
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

38. Prevention of Nausea and Vomiting
• Nonpharmacologic Techniques:
1. Acupuncture,
2. acupressure, and
3. transcutaneous electrical nerve stimulation

39. Prevention of Aspiration Pneumonitis
• H2-Receptor Antagonists
• Proton Pump Inhibitors,
• NPO Guidelines,

40. 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.

41. 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

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