Anestesia generale in daysurgery

Anestesia generale in daysurgery

tecniche e farmacitecniche e farmaci

Claudio MelloniClaudio Melloni

Bologna-FaenzaBologna-Faenza

CM 2001

Requirements of GA for ambulatory surgeryRequirements of GA for ambulatory surgery

psychological and pharmacological preparationpsychological and pharmacological preparation

rapid and predictable induction of anesthesiarapid and predictable induction of anesthesia

smooth and reliable maintenancesmooth and reliable maintenance

hypnosis,amnesia,surgical anesthesiahypnosis,amnesia,surgical anesthesia

cardiovascular stabilitycardiovascular stability

excellent surgical conditionsexcellent surgical conditions

prompt and complete recovery of mental facultiesprompt and complete recovery of mental faculties

physical capability to return home safelyphysical capability to return home safely

mimimal postop.side effectsmimimal postop.side effects

PONV,dizziness,pain...PONV,dizziness,pain...

prompt return to normal activitiesprompt return to normal activities

Essential intraoperative monitoringEssential intraoperative monitoringguidelinesguidelines

continuous presence of trained anesthesia personnelcontinuous presence of trained anesthesia personnel

continual assessment of ofcontinual assessment of of

oxygenationoxygenation

ventilationventilation

circulationcirculation

temperaturetemperature

clinical asessment+ standards of careclinical asessment+ standards of care

pulse oxymetrypulse oxymetry

capnographycapnography

NIBPNIBP

ECGECG

FiO2FiO2

disconnect alarmdisconnect alarm

thermometrythermometry

Choice of technique I

• surgical requirements

• anaesthetic considerations

• patient's physical status

• Patient preference. • The goal is to anaesthetize the patient for the

shortest possible time with the lowest concentration of anaesthetic.

Choice of technique II

• Intraop optimal conditions

• Fast recovery of consciousness

• Minimal,if any,sedative residual effects

• Minimal disturbance of cognitive postop.functions

• No side effects during recovery;No ponv,

• Fast discharge with early ambulation(???)

DebateDebateGas vs TIVAGas vs TIVA

GasGas

advantagesadvantages

induction withoutveininduction withoutvein

easy maintenanceeasy maintenance

easy recoveryeasy recovery

familiar...familiar...

disadvantagesdisadvantages

pollutionpollution

Ponv...Ponv...

Point threePoint three

DebateDebateTIVATIVA

AdvantagesAdvantages

no pollutionno pollution

smoothemergence...smoothemergence...

postop.analgesiapostop.analgesia

smooth induction(after i.v...).smooth induction(after i.v...).

DisadvantagesDisadvantages

knowledge ofpk-pdknowledge ofpk-pd

less easyless easy

less reversibleless reversible

Basic physico-chemical properties of modern inhalational

agents:• Low blood/ gas solubilities

»fast induction and emergence

• No active metabolites

• Recovery times not dependent from anesthesia duration

Inhalationinduction

• Ideal characteristics for an inhaled agent useful for induction:

• Low blood gas solubility• Pleasant smell• Nonirritating for the airway• High potency• sevoflurane ??

Characteristics of inhaled anesthetics

Decomposesnone2,424150,20,75197,4halothane

Stablemoderate

1,917556.51,68184,5enflurane

Stablemoderate

1.423848.51.15184,5isoflurane

decomposesno0,6016058.52.0200sevoflurane

stableno0,4739000gas

-8810544N2O

stableyes0,4266323.56168desflurane

Soda limepungencyBlood/gas partition coeff.

Vapor press.

Boling point

MACmwagent

Rate of equilibration between alveolar concentration and

inspired concentration NNNNNN2O

N2O

sevoflurane

Fa/Fi

0.4

0.6

0.8

The interaction between fentanyl and isoflurane(BJA 1998,81,38-50)

Interaction between remifentanil and isofluraneIsoflurane concentration reduction by increasing remifentanil whole blood

concentrationAnesthesiology85:721-8, 1996

Sebel PS., Glass PSA,Fletcher JE,Murphy M,Gallagher C,Quill T.Reduction of rhe Mac of

desflurane with fentanyl. Anesthesiology76:52-59, 1992

Sevoflurane Mac awake reduction by fentanylKatoh T,Iked K. The Effects of Fentanyl on Sevoflurane Requirements for Loss of

Consciousness and Skin Incision ANESTHESIOLOGY 1998; 88:5—6.

Context sensitive half time of opioids(influence of P450

3A4 on alfentanil)

Inhalational anesthesia vs TIVAInhalational anesthesia vs TIVAsimilarities...similarities...

parameterparameter inhalation anesth.inhalation anesth. TIVATIVA

cont.adm.cont.adm. yesyes yesyes

methodmethod vaporizervaporizer syringe pumpsyringe pump

titrationtitration yesyes yesyes

how much?how much? MACMAC MIRMIR

transporttransport airwayairway i.v.i.v.

initinit overpressureoverpressure bolusbolus

basal analgbasal analg N2O/titrationN2O/titration analgesicsanalgesics

pre-intraop checkspre-intraop checks yesyes yesyes

Plasma alfentanil vs propofol blood concentrations for 95% probability of no response to surgical stimulation(Vuyk et al.Propofol Anesthesia and Rational Opioid Selection: Determination of Optimal EC50-EC95 Propofol—

Opioid Concentrations that Assure Adequate Anesthesia and a Rapid Return of Consciousness Anesthesiology

87:1549-62, 1997

PharmacodynamicsPharmacodynamicsassumptionsassumptions

MEACMEAC

fent:0.6ng/mlfent:0.6ng/ml

Respdepression

Respdepression

>2 ng/ml>2 ng/ml

MACreduction

MACreductionCSHTCSHT

RecoveryRecovery

ED95 intraop for surgery/ED95 for recovery of consciousness & spont.resp.ED95 intraop for surgery/ED95 for recovery of consciousness & spont.resp.

Vuyk J,Mertens MJ,Olofsen EPropofol Anesthesia and Rational Opioid

Selection: Determination of Optimal EC50-EC95 Propofol—Opioid Concentrations that Assure Adequate Anesthesia and a Rapid Return of

Consciousness Anesthesiology

87:1549-62, 1997

time

Propofol blood concOpioid blood concentration

Three dimensional planes in the graphs from Vuyk et al.

manual opioid infusion schemesmanual opioid infusion schemesfrom many sources...from many sources...

drugdrug plasma targetconcentation(ngml)plasma targetconcentation(ngml) bolus(microgr/kg)bolus(microgr/kg)

infusion rate(microgr/kg/mininfusion rate(microgr/kg/min

fentanylfentanyl 11 33 0.0200.020

fentanylfentanyl 44 1010 0.0700.070

alfentanilalfentanil 4040 2020 0.250.25

alfentanilalfentanil 160160 8080 1.001.00

sufentanilsufentanil 0.150.15 0.150.15 0.0030.003

sufentanilsufentanil 0.500.50 0.500.50 0.0100.010

remifentanilremifentanil 66 11 0.020.02

remifentanilremifentanil 12-2012-20 1-21-2 0.4-1.00.4-1.0

Practical pharmacokinetics as applied to our daily anesthesia practice

Fiset, Pierre.Can J Anesth 1999 / 46 / R122-R126

Bekke AY, Berklay P, Osborn I,Bloo M, Yarmush J, Turndorf H. The Recovery of Cognitive Function After Remifentanil- Nitrous Oxide Anesthesia Is Faster than

After an Isoflurane-Nitrous Oxide-Fentanyl Combination in Elderly Patients Anesth Analg 2000; 91:117–22• We tested the hypothesis that remifentanil-nitrous oxide (N2O) anesthesia shortens postoperative

emergence and recovery compared with an isoflurane-N2O-fentanyl combination in elderly patients undergoing spinal surgery.

• 60 patients (>65 yr old) were randomly assigned to one of two groups for maintenance of anesthesia. After the induction with 3.6 ± 1.2 mg/kg IV thiopental and endotracheal intubation facilitated with 1.4 ± 0.5 mg/kg succinylcholine, patients were maintained with either 0.5%–1.5% isoflurane, 70% N2O, and up to 7 mg/kg fentanyl (iso/fent group) or 48 ± 11 mg/kg remifentanil and 70% N2O (remi group).

• A mini-mental status examination was used to assess cognitive ability preoperatively, at 15, 30, and 60 min after arrival at the postanesthesia care unit and again 12–24 h postoperatively. The time from the conclusion of anesthesia to spontaneous respiration was similar in both groups. Times to eye opening (4.8 ± 2.6 vs 2.3 ± 1.1 min), extubation (6.8 ± 3.8 vs 3.2 ± 2.1 min), and verbalization (9.9 ± 6.2 vs 3.9 ± 2.6 min) were significantly shorter for the remi group (P < 0.05). Postoperative mini-mental status examination scores were significantly lower in the iso/fent group at 15 (16.3 ± 5.8 vs 23.7 ± 3.3), 30 (20.2 ± 5.2 vs 26.3 ± 2.7), and 60 min (23.5 ± 4.4 vs 27.5 ± 2.0) (P < 0.001); however, the scores equalized after 12 h. Requirements for postoperative analgesics were similar in the two groups. More patients in the remi group were treated with antiemetics (21 vs 7, P = 0.06). Use of remifentanil-N2O for maintenance did not shorten the overall length of stay in the postanesthesia care unit; a stay is often related to multiple administrative issues, rather than cognitive recovery.

Bekke et al The Recovery of Cognitive Function After Remifentanil- Nitrous Oxide Anesthesia Is Faster than After an Isoflurane-Nitrous Oxide-Fentanyl Combination in Elderly Patients Anesth Analg 2000; 91:117–22

Isofl/fent

Remif/N2O

Black ML. Hill JL, Zacny JP. Behavioral and Physiological Effects of Remifentanil and

Alfentanil in Healthy Volunteers Anesthesiology90:718-26, 1999

• Background: The subjective and psychomotor effects of remifentanil have not been evaluated.

Accordingly, the authors used mood inventories and psychomotor tests to characterize the effects of remifentanil in healthy, non—drug-abusing volunteers. Alfentanil was used as a comparator drug.

• Methods: Ten healthy volunteers were enrolled in a randomized, double-blinded, placebo-controlled, crossover trial in which they received an infusion of saline, remifentanil, or alfentanil for 120 min. The age- and weight-adjusted infusions (determined with STANPUMP, a computer modeling software package) were given to achieve three predicted constant plasma levels for 40 min each of remifentanil (0.75, 1.5, and 3 ng/ml) and alfentanil (16, 32, and 64 ng/ml). Mood forms and psychomotor tests were completed, and miosis was assessed, during and after the infusions. In addition, analgesia was tested at each dose level using a cold-pressor test.

• Results: Remifentanil had prototypic m-like opioid subjective effects, impaired psychomotor performance, and produced analgesia. Alfentanil at the dose range tested had more mild effects on these measures, and the analgesia data indicated that a 40:1 potency ratio, rather than the 20:1 ratio we used, may exist between remifentanil and alfentanil. A psychomotor test administered 60 min after the remifentanil infusion was discontinued showed that the volunteers were still impaired, although they reported feeling no drug effects.

• Conclusions: The notion that the pharmacodynamic effects of remifentanil are extremely short-lived after the drug is no longer administered must be questioned given our findings that psychomotor effects were still apparent 1 h after the infusion was discontinued.

•

remi

alf

remi

alf

Beers R,Calimlim JR, Uddoh E,Esposito B, Camporesi EM.A Comparison of the Cost-

Effectiveness of Remifentanil Versus Fentanyl as an Adjuvant to General Anesthesia for

Outpatient Gynecologic Surgery Anesth Analg 2000; 91:1420

• The unique pharmacokinetic properties of remifentanil make it a potentially useful adjuvant during general anesthesia for ambulatory surgery. Fentanyl, inexpensive and easy to administer, is the most common opioid used for this purpose. As an adjuvant to general anesthesia for outpatient gynecologic surgery, we questioned if remifentanil was cost-effective as an alternative to fentanyl. Thirty-four patients undergoing gynecologic laparoscopy or hysteroscopy were prospectively and randomly assigned to a standard practice (n = 18) or a study (n = 16) group. Standard practice patients received fentanyl(3 mg/kg) before induction; study patients received remifentanil by continuous infusion (0.5 mg×kg×min-1 at induction, then 0.2 mg×kg×min-1). Sevoflurane was titrated to a Bispectral index value of 40–55.

• Fentanyl administered to studty pts for analgesia before awakening! the We investigated recovery profiles, patient and health care professional satisfaction, and drug costs . The incidence of rescue antiemetic treatment (2 of 16 vs 8 of 18; P = 0.013) and the nausea visual analog scale scores during second stage recovery (0.2 vs 0.6; P = 0.044) were more frequent in the study group. However, the incidence of intraoperative adverse events and other postoperative sequelae, recovery times, pain and nausea visual analog scale scores, opioid analgesic dosage requirements in the postanesthetic care unit, and satisfaction survey responses were similar between groups. Perioperative drug costs per patient were $17.72 more in the remifentanil (vs fen-tanyl) group.

Rosenberg et al.Cost comparison:a desflurane versus a propofol based general anesthetic

technique.AA 1994;79:

020406080

100120140

cost

/hr

cost

was

teto

t.cos

t/hrd

urat

ion

tot c

ost/h

rt

Pacu

sta

y

prop/n2Odesf/O2

**

*

0.09

Chung F. Recovery pattern and home readiness after ambulatory surgery. Anesth Analg 1995;

80:896-902

• Despite increased use of ambulatory surgery, few data exist regarding patient recovery patterns and home-readiness. We prospectively identified the pattern of home-readiness, the persistent symptoms after surgery, and the factors that delay discharge after home-readiness criteria are satisfied. Five hundred patients were scored by the same investigator using the Postanesthetic Discharge Scoring System (PADSS) every 30 min, commencing 30 min after surgery, until the PADSS score was > or = 9. The same investigator telephoned each patient 24 h after discharge to administer a standardized questionnaire so that postoperative symptoms could be identified. Eighty-two percent of patients were discharged 2 h and 95.6% 3 h after surgery. These patients could have been discharged earlier. After home-readiness criteria were satisfied, some patients had delayed discharge because of the unavailability of immediate escorts or the recurrence of pain. Persistent symptoms delaying discharge occurred in 4.4% of patients. Patients who underwent POcertain ambulatory surgical procedures, such as laparoscopy or orthopedic and general surgery, had a sixfold increased risk of developing persistent symptoms in the ambulatory surgery unit. The time to home-readiness was 2.5-fold longer and the incidence of 24-h postoperative symptoms, two- to eightfold higher in the group with persistent symptoms in the ambulatory surgery unit. In summary, periodic objective evaluation of home-readiness revealed that the majority of patients would achieve a satisfactory score on or before 2 h after surgery. The time to home-readiness by objective evaluation correlated with the type of surgery. Most delays after satisfactory home-readiness scores were reached were due to nonmedical reasons

Discharge of the patient vs homereadiness

Discharge of the patient vs homereadiness

ChungChung

patterns of home readinesspatterns of home readiness

persistent symptomspersistent symptoms

recurrence of painrecurrence of pain

PONVPONV

factors that delay dischargefactors that delay discharge

unavailability of escortsunavailability of escorts

Laparscopy,general surg,orthopedic surg

Anesthesia and factorsassociated with PONVAnesthesia and factorsassociated with PONV

GA> regGA> reg

etomidate,ketamine,(neostigmine),(N2O)etomidate,ketamine,(neostigmine),(N2O)

PAINPAIN

Sudden movementSudden movement

HypotensionHypotension

Gastric distentionGastric distention

PONVPONVCategories at riskCategories at risk

FemalesFemales young,pregnantyoung,pregnant

kinetosiskinetosis

certain operationscertain operations strabismus, innerear,pelvic laparoscopic ...strabismus, innerear,pelvic laparoscopic ...

diabeticsdiabetics

PONVPONVwe know the risk factorswe know the risk factors

Preventive strategyPreventive strategy non emetogenic drugs...non emetogenic drugs...

AntiemeticProphylaxisAntiemetic

ProphylaxisSelected at risk groupsSelected at risk groups

Immediate treatmentImmediate treatment in case ofoccurrence.....in case ofoccurrence.....

Propofol & PONV

YES,>ondansetron (preop..)

Induz vs intraop

Tps/isof vs prop/N2O

major breast surgery

Gan 1996

Fem outpts laparoscopic surgery

Mayot gynecol surg

thyroidectomy

Gynecol lap

procedure

YESintraopEnflur/N2O vs propof/N2O

Ding 1993

YESPostop 0.1 ml/kg/h

enflurane Montgomery 1996

YESPostop,0.1 ml/kg/h

Isof/N2OEwalenko 1996

NonepostopisoflCampbell 1991

effectsPropofol adm.

Inh.agentAuthor

PONV prophylaxis and treatment

• Droperidol 10 microgr/kg ev/im++• Ondansetron 4-8 mg ev(8 p.o.)++• Dexamethasone 4 mg ev+• Ephedrine 10 mg iv?• Scopolamine 0.5 mg/62 hr patch ??• Metoclopramide 10 mg iv +/-• Propofol 10-20 mg ev??• “setrons”++

How well do we manage pain?

• 77% of patients still experience pain postoperatively:80% moderate-severe and 57% quote pain as a primary concern or preop fear(Acute Pain Management: Programs in U.S. Hospitals and Experiences and Attitudes among U.S. Adults Anesthesiology,83:1090-1094, 1995)

Acute Pain Management: Programs in U.S. Hospitals and Experiences and Attitudes among

U.S. Adults Anesthesiology

83:1090-1094, 1995• Two telephone questionnaire surveys • U.S. hospital participants: 100 teaching hospitals (acute care hospitals with a residency

program and/or university affiliation), 100 nonteaching (community) hospitals with fewer than 200 beds, and 100 nonteaching (community) hospitals with 200 beds or more

• interview regarding current and future pain management programs and related topics. • Adult participants in 500 U.S. households were interviewed on attitudes and experiences

with postoperative pain and its management.• Results: Forty-two percent of the hospitals have acute pain management programs, and

an additional 13% have plans to establish an acute pain management program. Seventy-seven percent of adults believe that it is necessary to experience some pain after surgery. Fifty-seven percent of those who had surgery cited concern about pain after surgery as their primary fear experienced before surgery. Seventy-seven percent of adults reported pain after surgery, with 80% of these experiencing moderate to extreme pain.

• Conclusions: Despite a growing trend in pain management, increased professional and public awareness including the establishment of pain management programs and public and patient education is needed to reduce the incidence and severity of postoperative pain.

Song et al. Titration of Volatile Anesthetics Using Bispectral

Index Facilitates Recovery after Ambulatory Anesthesia Anesthesiology

87:842-8, 1997

-4

-2

0

2

46

8

10

12

14

% or min

Gas % Mac/hr verbresp

extub orient

SEVO BISsevocontrDESFL BISdesfl contrdiff bis-contr desfdiff bis-contr sevo

Song et al. Titration of Volatile Anesthetics Using Bispectral Index

Facilitates Recovery after Ambulatory Anesthesia Anesthesiology87:842-8, 1997

Song D, van Vlymen J, White PF.Is the Bispectral Index Useful in Predicting Fast-Track

Eligibility After Ambulatory Anesthesia with Propofol and Desflurane?

Anesth Analg 1998; 87:1245

Dexter F, Tinker JH..Comparison between desflurane and isoflurane or propofol on time to following commands and

time to discharge:a metanalysis.Anesthesiology 1995; 83,

Dexter F, Tinker JH..Comparison between desflurane and isoflurane or propofol on time to following commands and

time to discharge:a metanalysis.Anesthesiology 1995; 83,

Dexter F, Tinker JH..Comparison between desflurane and isoflurane or propofol on time to following commands and

time to discharge:a metanalysis.Anesthesiology 1995; 83,

Dexter F, Tinker JH..Comparison between desflurane and isoflurane or propofol on time to following commands and

time to discharge:a metanalysis.Anesthesiology 1995; 83,

Dexter F, Tinker JH..Comparison between desflurane and isoflurane or propofol on time to following commands and

time to discharge:a metanalysis.Anesthesiology 1995; 83,

Song et al.Remifentanil infusion facilitates early recovery for obese outpatients undergoing

laparoscopic cholecystectomy.AA 2000,90:1111-3.

0

2

46

8

10

12

1416

18

sevo% opioidintraop

awake extub orient

sevoremif

*

**

*

mg

min

Conclus from Song et al

• Variable rate infus of remif(0.09 microgr/kg/min) + sevo + N2O :

• 50% sevo %

• Contributed to a more rapid emergence

• Postop side effects not increased(PONV=)

• PACU stay and discharge times =

Joshi et al.Use of the Laryngeal Mask Airway as an Alternative to the Tracheal Tube During

Ambulatory Anesthesia Anesth Analg 1997; 85:573

0

20

40

60

80100

120

140

160

180

fent mant PACU-stepdown

PACU-ambul

sore throat nausea

LMAIOT

microg

min

min

% %

Advantages of the LMA>TT

• increased speed and ease of placement by inexperienced personnel;

• increased speed of placement by anaesthetists;• improved haemodynamic stability at induction and during

emergence;• minimal increase in intraocular pressure following

insertion; • reduced anaesthetic requirements for airway tolerance; • lower frequency of coughing during emergence;• improved oxygen saturation during emergence; • lower incidence of sore throat in adults.

Advantages LMA>Face Mask

• easier placement by inexperienced personnel;

• improved oxygen saturation;

• less hand fatigue;

• improved operating conditions during minor paediatric otological surgery.

Disadvantages LMA> TT&FM

• lower seal pressures

• higher frequency of gastric insufflation.

• The only disadvantage compared with the FM was that oesophageal reflux was more likely.

In conclusionIn conclusionfor the success of day anesthesia & surgeryfor the success of day anesthesia & surgery

pk-pdfoundations

pk-pdfoundations

clinicalexperience

clinicalexperience

organizationorganization

continuousimprovementcontinuous

improvement

pk/pdfoundations

pk/pdfoundations

technology?technology?