ppt shiver

2003/11/26 Chih-Min Liu 1

Postanesthetic Postanesthetic ShiveringShivering

Epidemiology, Epidemiology, Pathophysiology, Prevention Pathophysiology, Prevention

and Managementand Management

2003/11/26 2Chih-Min Liu

ReferenceReference

Perioperative ShiveringPerioperative Shivering Physiology and PharmacologyPhysiology and Pharmacology

Anesthesiology 2002; 96: 467-84Anesthesiology 2002; 96: 467-84 Postanesthetic ShiveringPostanesthetic Shivering

Epidemiology, Pathphysiology, and Epidemiology, Pathphysiology, and Approaches to Prevention and Approaches to Prevention and ManagementManagement Drugs 2001; 61 (15): 2193-2205Drugs 2001; 61 (15): 2193-2205

Clinical Anesthesiology, third editionClinical Anesthesiology, third edition Chapter 6: Patient monitors; 117-120Chapter 6: Patient monitors; 117-120


Clinical ConsiderationsClinical Considerations Hypothermia: < 36 Hypothermia: < 36 ooCC OO22 consumption x 5; decrease saturation; consumption x 5; decrease saturation;

myocardial ischemia and angina myocardial ischemia and angina Increased mortality rateIncreased mortality rate Monitoring site:Monitoring site:

Tympanic membrane: brain temperatureTympanic membrane: brain temperature Nasopharyngeal mucosa: core temperatureNasopharyngeal mucosa: core temperature Rectum: slow response in change to core Rectum: slow response in change to core

temptemp Esophagus Esophagus


EpidemiologyEpidemiology 40-60% after volatile anesthetics40-60% after volatile anesthetics Young male adult, rare in elder (age impairs Young male adult, rare in elder (age impairs

thermoregulatory control)thermoregulatory control) Length of anesthesia or surgeryLength of anesthesia or surgery Peri-op rewarming procedure: if notPeri-op rewarming procedure: if not Mild hypothermia Mild hypothermia

The more serious hypothermia, the higher the The more serious hypothermia, the higher the probabilityprobability

Anesthetic used Anesthetic used Less common with propofol; more with halogenated Less common with propofol; more with halogenated

agent, pentothalagent, pentothal


Pathophysiology Pathophysiology

Consequence of postanesthetic Consequence of postanesthetic shiveringshivering DiscomfortDiscomfort Increased painIncreased pain IICP, IOPIICP, IOP OO22 consumption (VO consumption (VO22): more 40 ): more 40 –– 120% 120% Increased minute ventilationIncreased minute ventilation Cardiac morbidityCardiac morbidity



Two types of postanesthetic Two types of postanesthetic shiveringshivering Thermoregulated shiveringThermoregulated shivering

With cutaneous vasoconstriction, the With cutaneous vasoconstriction, the response of hypothermiaresponse of hypothermia

Perioperative hypothermiaPerioperative hypothermia Non-thermoregulated shiveringNon-thermoregulated shivering

Mechanism unknownMechanism unknown Postoperative pain related?Postoperative pain related?



Origins of Postanesthetic ShiveringOrigins of Postanesthetic Shivering Perioperative hypothermiaPerioperative hypothermia Postoperative painPostoperative pain Perioperative heat lossPerioperative heat loss Direct effect of certain anestheticsDirect effect of certain anesthetics Hypercapnia or respiratory alkalosisHypercapnia or respiratory alkalosis The existence of pyogensThe existence of pyogens HypoxiaHypoxia Early recovery of spinal reflex activityEarly recovery of spinal reflex activity Sympathetic overactivity Sympathetic overactivity


Perioperative Perioperative hypothermiahypothermia

32.5

33

33.5

34

34.5

35

35.5

36

36.5

37

37.5

0 1 2 3 4 5

Temp

Phase I: 1st hourPhase I: 1st hour Internal Internal

redistribution: from redistribution: from center to peripheral center to peripheral

Phase II: 2-4 hoursPhase II: 2-4 hours Heat loss: skin, Heat loss: skin,

visceraviscera Phase III: Phase III:

Steady-stateSteady-state



Early recovery of spinal reflex Early recovery of spinal reflex activityactivity Residual effect of anesthetics on the Residual effect of anesthetics on the

inhibiting control exercised by inhibiting control exercised by supraspinal structuresupraspinal structure

Propofol in low concentration may have Propofol in low concentration may have less effect on certain central structure less effect on certain central structure such as the reticular formation, thus such as the reticular formation, thus faster recovery of descending inhibiter faster recovery of descending inhibiter controlcontrol


Temperature-regulating Temperature-regulating systemsystem

ThermosensorsThermosensors Skin to hypothalamusSkin to hypothalamus

Afferent pathway, Afferent pathway, integration areaintegration area

Spinal cordSpinal cord Modulate: Modulate:

NRM( serotonin), LS(NE)NRM( serotonin), LS(NE) Integration inputs: PO-Integration inputs: PO-

AHAH Efferent pathwayEfferent pathway

Central descending Central descending shivering pathway: PHshivering pathway: PH

Multiple inputs>common Multiple inputs>common efferent signalefferent signal

Spinal Spinal αα motor neurons, motor neurons, axonsaxons


PathophysiologyPathophysiology

Human defenses to hypothermia:Human defenses to hypothermia: Skin vasomotor activitySkin vasomotor activity Nonshivering thermogenesisNonshivering thermogenesis

Cell metabolic without mechanical work, Cell metabolic without mechanical work, NeonateNeonate

ShiveringShivering Sweating Sweating

Shivering is the last-resort defense Shivering is the last-resort defense


PathophysiologyPathophysiology Shivering Shivering

Several typesSeveral types 4-8 Hz., waxing-and-waning pattern4-8 Hz., waxing-and-waning pattern

Postanesthetic tremorPostanesthetic tremor Thermoregulatory inhibition abruptly Thermoregulatory inhibition abruptly

dissipates, thus increasing the shivering dissipates, thus increasing the shivering threshold toward normalthreshold toward normal

New, near-normal threshold activate New, near-normal threshold activate shiveringshivering

Shivering like activityShivering like activity Pain in post-op and labor femalePain in post-op and labor female


Prevention & Prevention & ManagementManagement

Perioperative Hypothermia PreventionPerioperative Hypothermia Prevention Limiting the effects of internal redistributionLimiting the effects of internal redistribution

Skin surface rewarming with Skin surface rewarming with forced-air warmerforced-air warmer for 30 minutes for 30 minutes

Reduce heat lossReduce heat loss Radiation from skin surfaceRadiation from skin surface Room temperature > 23Room temperature > 23ooC if the op field is largeC if the op field is large Cover the patient as much as possibleCover the patient as much as possible

Intravenous fluid rewarmingIntravenous fluid rewarming



Passive prevention is not enoughPassive prevention is not enough Active heat transfer Active heat transfer

Cutaneous patchCutaneous patch is the most efficient is the most efficient Forced warm airForced warm air better then better then…… Water circulation blanketsWater circulation blankets

1/3 cover of the cutaneous surface is 1/3 cover of the cutaneous surface is enoughenough

Under GA > vasodilatation > heat lossUnder GA > vasodilatation > heat loss



Physical treatmentPhysical treatment Shivering threshold: Shivering threshold:

skin 20%, core 80% skin 20%, core 80% Raise temp to inhibit postoperative Raise temp to inhibit postoperative

shivering: shivering: skin 4skin 4ooC = core 1C = core 1ooCC

Radiation heat systemRadiation heat system Forced air warmer: Forced air warmer:

reduce frequency and duration of shiveringreduce frequency and duration of shivering



Medical treatmentMedical treatment OpiatesOpiates Tramadol, Ketanserin, Nefopam and Tramadol, Ketanserin, Nefopam and

OndensetronOndensetron αα2-Adrenergic Agonists2-Adrenergic Agonists Other drugsOther drugs


Opiates Opiates MeperidineMeperidine

DemoralDemoral ΚΚ-opioid receptor-opioid receptor Shivering thresholdShivering threshold VasoconstrictionVasoconstriction Sweating Sweating

Others:Others: Pure Pure μμ-receptor agonists-receptor agonists Morphine, alfentanyl, fentanylMorphine, alfentanyl, fentanyl

Sites of actionSites of action PO-AH, dorsal raphe nucleus neurons, RMN, PO-AH, dorsal raphe nucleus neurons, RMN,

LS, and the spinal cordLS, and the spinal cord


Meperidine( Demoral) Meperidine( Demoral)

SweatingSweating VasoconstrictionVasoconstriction Shivering Shivering

thresholdthreshold


Tramadol, Ketanserin, Tramadol, Ketanserin, Nefopam and OndensetronNefopam and Ondensetron

The The balancebalance of Norepinephrine and of Norepinephrine and serotonin(5-HT) in the PO-AH controls the body serotonin(5-HT) in the PO-AH controls the body temperature set pointtemperature set point

5-HT induce hyperthermia; 5-HT induce hyperthermia; αα2-Adrenergic 2-Adrenergic Agonists (clonidine) reduce core temperatureAgonists (clonidine) reduce core temperature

Opposite modulatory inputs from NE and Opposite modulatory inputs from NE and serotonergic neurons shifting the shivering serotonergic neurons shifting the shivering thresholdthreshold

All 4 drugs acts on the serotonin neuromediatorAll 4 drugs acts on the serotonin neuromediator Encourage the inhibiting effect of serotonin on Encourage the inhibiting effect of serotonin on

OP-AHOP-AH


Tramadol, Ketanserin, Tramadol, Ketanserin, Nefopam and OndensetronNefopam and Ondensetron

TramadolTramadol Inhibits reuptake of 5-HT, NE, dopamine and facilitate 5-HT Inhibits reuptake of 5-HT, NE, dopamine and facilitate 5-HT

release release Site of action: PonsSite of action: Pons Analgesic effect, non-opioid analgesicAnalgesic effect, non-opioid analgesic 1 mg/kg for shivering, reduce threshold by 0.81 mg/kg for shivering, reduce threshold by 0.8ooCC

Nefopam Nefopam Inhibits reuptake of 5-HT, NE, dopamine and lower normal Inhibits reuptake of 5-HT, NE, dopamine and lower normal

body temperaturebody temperature Analgesic effect, 0.15mg/kg or 20mgAnalgesic effect, 0.15mg/kg or 20mg

Ketanserin Ketanserin Low efficacyLow efficacy Antihypertensive effect, 5 HTAntihypertensive effect, 5 HT22 antagonist, 10mg antagonist, 10mg

OndensetronOndensetron Antiemetic, 5 HTAntiemetic, 5 HT33 antagonist, 8mg antagonist, 8mg


αα2-Adrenergic Agonists2-Adrenergic Agonists Clonidine 75Clonidine 75μμg g

lower the threshold of cutaneous lower the threshold of cutaneous vasoconstriction and shivering by 0.5vasoconstriction and shivering by 0.5ooCC

Bolus & perfusion: Bolus & perfusion: At the end of op: 1.5 or 3At the end of op: 1.5 or 3μμg/kgg/kg Cardiac surgery: 200 to 300Cardiac surgery: 200 to 300μμgg

Mechanism: Mechanism: CentralCentral Shivering centre is under inhibiting control of Shivering centre is under inhibiting control of

the preoptic anterior hypothalamic regionthe preoptic anterior hypothalamic region αα2-Adrenergic Agonists probably strengthened it 2-Adrenergic Agonists probably strengthened it

DexmedetomidineDexmedetomidine


Other drugsOther drugs Other drugsOther drugs

NMDA receptor antagonist: NMDA receptor antagonist: Ketamine Ketamine Magnesium sulfate 30mg/kgMagnesium sulfate 30mg/kg

Methylphenidate 20mg Methylphenidate 20mg Analeptic agent, block reuptake of 5-HTAnaleptic agent, block reuptake of 5-HT

Physostigmine 0.04mg/kgPhysostigmine 0.04mg/kg Central acting cholinesterase inhibitorCentral acting cholinesterase inhibitor

Doxapram 100mg or 1.5mg/kgDoxapram 100mg or 1.5mg/kg Respiratory stimulant, central action on ponsRespiratory stimulant, central action on pons

Recovery of the descending inhibitor control of Recovery of the descending inhibitor control of the supraspinal effecting centersthe supraspinal effecting centers


Conclusion Conclusion Hypothermia is associated with shivering and many Hypothermia is associated with shivering and many

complications, patient should be kept normothermiacomplications, patient should be kept normothermia Prevention of hypothermia consists of limiting heat loss Prevention of hypothermia consists of limiting heat loss

and active rewarming systemand active rewarming system Effective treatment of shivering will reduce metabolic heat Effective treatment of shivering will reduce metabolic heat

production and must be accompanied by an effective active production and must be accompanied by an effective active heating system.heating system.

Skin surface rewarming is less efficient then medical Skin surface rewarming is less efficient then medical treatment with meperidine, tramadol, or, in certain treatment with meperidine, tramadol, or, in certain situations, clonidinesituations, clonidine

All antishivering drugs except ketanserin have some All antishivering drugs except ketanserin have some analgesic properties in humans, suggested that pain and analgesic properties in humans, suggested that pain and thermoregulation are tightly connectedthermoregulation are tightly connected

No single structure or pathway is responsible for the No single structure or pathway is responsible for the shivering responseshivering response

2003/11/26 Chih-Min Liu 24

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ppt shiver

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skin surface

adrenergic

prevention

min liu

internal redistribution

postanesthetic

shivering

hypothermia