Current Controversies in Adult Outpatient Anesthesia

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Current Controversies in Adult Outpatient
Anesthesia

• R 3 ? ? ?

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• 1970freestanding ambulatory surgery
  
  movement was initiated
• the end of 1997
• nearly 70 of all surgeries performed in
  the US will be done on an ambulatory basis

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Value-based Anesthesia Care What Is It? What
Does It Mean to Anesthesiologists?

• Orkin
• "value-based care"
• - essentially the best patient outcome
  achievable at a reasonable cost

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The Changing Role of the Anesthesiologist The
Hows and Whys of Preoperative Evaluation
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• Outpatient surgery growth
• Anesthesiologists demand skills choosing a good
  anesthetics
• Anesthesiologist physician
• Pre-op interview evaluation by a consultant
  anesthesiologist can be beneficial
• Lessening anxiety about op. ane
• Identify medical problems
• Initiate appropriate corrective measure
• Goal resolve pre-op problems minimizing No.
  of cancellation Cx.

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Several approach used to screen pt for ambulatory
surgery

• Facility visit
• Office or clinic visit
• Telephone interview with no visit
• Review of Health questionnaire
• Morning of operation visit
• Computer-assisted information gathering

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Should pt. Age or ASA status influence case
selection?

• Past ambulatory surgical facilities arbitrarily
  with regard to age ASA
• Meridy
• could not demonstrate age-related effect
• Methodist ambulatory surgicare center
• unanticipated admission rate 1.1(gt60yr)-
  0.8(overall)
• Natof ASA3 no higher risk than 1,2
• FASA little or no relation bteween preexisting
  disease and the incidence of periop. Cx.

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• Outpatient surgery is no longer restricted to
  young, healthy patients.
• Geriatric and ASA3,4 acceptable candidates for
  outpatient surgery if systemic diseases are well
  controlled.

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What laboratory tests are really needed?

• Most tests not contribute beneficially to
  periop Mx.
• Lab. Test possess shortcoming
• Fail to uncover pathologic condition
• Abnormalities not necessarily improve pt. Care or
  outcome
• Inefficient in screening
• Often not appropriately followed
• False-positive result

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• 30billion spent were spent on pre-op test
  evaluation in U.S. in 1984
• (12-18billion could be saved)
• Many facilities now determine
• pre-op test are required based on the
  operative procedure and pt age, preexisting
  medical disease, medical history

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The inappropriate patientwhos OK and whos not

• Few data exist
• Anesthesiologist experience ?
• ? list of inappropriate patients?
• At the University of Chicago hospital
• distinguished several groups of patients may
  not be appropriate candidates for ambulatory
  surgery
• -Unstable pt. Classified as ASA 3 and 4
• -malignant hyperpyrexia
• -MAO inhibitors
• -complex morbid obesity
• -acute substance abuse
• -psychosocial difficulties

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• Discharge criteria for the 21st century
• Can short-acting, fast-emergence anesthetics
  make a difference?
• Do all patients really need to go to the
  postanesthesia care unit?

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• RR is no longer the cash cow in a fee-for service
  system.
• Increasingly important for the anesthesiologist
  to accurately assess the earliest time when pt.
  Can be safely sent home after surgery.
• PACU
• shall be available to receive pts after
  surgery and anesthesia.
• all pts. who receive anesthesia shall be
  admitted to the PACU
• ? current standard

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Table 1.

• Awake,alert,oriented, responsive(or return to
  baseline
• Minimal pain
• No active bleeding
• Vital signs stable
• Minimal nausea
• No vomiting
• If non-depol NM blockers used, can perform
  5-second head tilt
• SaO2 94
• On room air

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Important lessons from short-acting,
Fast-emergence study

• Pt-bypass first-stage PACU
• Surgical center-financial saving
• Table 1? ???? second-stage recovery unit?
• Important cost savings can be achieved without
  compromising patient safety after a bypass
  paradigm is implemented

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• Inhalational agents for ambulatory surgery into
  the 21st century Desflurane and Sevoflurane.
• Are they safe?
• Do they really make a difference?

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• Several agents introduction
• More rapid recovery, easy titration, fewer side
  effects
• Two new inhalation agents
• Sevoflurane desflurane
• Lower blood-gas solubility
• Greater control of anesthetic depth and more
  rapid recovery from GA

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Desflurane

• 1.Physical properties
• -very similar structure of isoflurane
• -low solubility in blood body tissues
  (?b/g 0.42)
• ? rapid induction emergence
• -most characteristic feature
• high vapor pressure,
• ultrashort duration of action,
• moderate potency

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• 2.Effects on organ systems
• A.cardiovascular
•     -isoflurane? ??
•     -arterial BP ?
•     -CO relatively uncahanged
•     -HR, CVP, pulmonary artery pressure ?
• B.resporatoy
•    -RR ?, TV ?
•    -pungency, airway irritation
•     ? induction? salivation, breathing- holding,
  coughing, laryngospasm?
• ??? ? ??.

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• C.cerebral
• -cerebral blood flow, ICP ?
• -autoregulation intact
• -CMRO2 ?
• D.neuromuscular
•    -response to train-of-four tetanic
  peripheral nerve stimulation ?
• E.renal
• -no evidence fo nephrotoxic effect
•  
• F.hepatic
• -no evidence of hepatic inj.

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• 3.Biotransmission toxicity
• -minimal metabolism
• 4.CIx
• -sever hypvolemia, malignant HTN, intracranial
  HTN
• 5.Drug interaction
• -epinephrine
• safely administered up to 4.5 ?/?
• -nondepolazing blocking agent? ??

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sevoflurane

• 1.Physical properties
• -halogenated with fluoride
• -excellent choice for inhalational
  induciton
• no pungency rapid FA

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• 2.Effect on organ system
• A.cardiovascular
• -mildly depress myocardial contractility
• -systemic vascular resistance
• arterial BP ?
• slightly of desflurane , isoflurane
• B.respiratory
•   -depress respiration
•   -bronchodilator

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• C.cerebral
• -cerebral blood flow ICP ?, CMRO2 ?
• -no seizure activity
• D.neuromuscular
• -adequate m.relaxation for intubation of child
• E.renal
• -renal blood flow slightly ?
• F. hepatic
• -total hepatic blood flow, O2 delivery? ??

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• 3.Biotransmssio toxicity
• -metabolize similar to enflurane
• -potentila nephrotoxicity
• 4.CIx
• -sever hypovolemia,
• malignant hyperthermia,
• intracranial HTN
• 5.Drug interaction
• -no sensitization of heart to dysrhythmic effect
  of epinephrine
• -nondepolarizing blocking agnet? ??