intraoperative monitoring

Intraoperative MonitoringIntraoperative Monitoring

Intraoperative monitoringIntraoperative monitoring :: Introduction
The most primitive method of monitoring theThe most primitive method of monitoring the
patient 25 years ago waspatient 25 years ago was continuous palpationcontinuous palpation
of theof the radial pulsationsradial pulsations throughout thethroughout the
operation!!operation!!

What is the value of knowing this?What is the value of knowing this?
 To understand & appreciate the value ofTo understand & appreciate the value of
clinicalclinical monitoring.monitoring.
 RULERULE:: youryour clinicalclinical
judgement/assessmentjudgement/assessment is muchis much
BETTERBETTER & much more& much more VALUABLEVALUABLE thanthan
the digital monitor.the digital monitor.
 To appreciate that modern monitors haveTo appreciate that modern monitors have
made life much easier for us. They aremade life much easier for us. They are
present to make monitoring easier for uspresent to make monitoring easier for us
NOT to be omitted or ignored.NOT to be omitted or ignored.

Why do we need intraoperative monitoring???Why do we need intraoperative monitoring???
 To maintain the normal pt physiology & homeostasisTo maintain the normal pt physiology & homeostasis
throughout anesthesia and surgery: induction,throughout anesthesia and surgery: induction,
maintenance & recovery as much as possible. To ensuremaintenance & recovery as much as possible. To ensure
the well being of the pt.the well being of the pt.
 Surgery is a very stressful condition → severeSurgery is a very stressful condition → severe
sympathetic stimulation, HTN, tachycardia, arrhythmias.sympathetic stimulation, HTN, tachycardia, arrhythmias.
 Most drugs used for general & regional anesthesiaMost drugs used for general & regional anesthesia
cause hemodynamic instability, myocardial depression,cause hemodynamic instability, myocardial depression,
hypotension & arrhythmias.hypotension & arrhythmias.
 Under GA the pt may beUnder GA the pt may be hypohypo oror hyperventilatedhyperventilated andand
may developmay develop hypothermiahypothermia..
 Blood loss → anemia, hypotension. So it is necessary toBlood loss → anemia, hypotension. So it is necessary to
recognise when the pt is in need of blood transfusionrecognise when the pt is in need of blood transfusion
(transfusion point)(transfusion point) ..

The FOUR BASIC MonitorsThe FOUR BASIC Monitors ::
 We are NOT authorised to start a surgery in theWe are NOT authorised to start a surgery in the
absence of any of these monitors:absence of any of these monitors:
 ECG.ECG.
 SpO2: arterial O2 saturation.SpO2: arterial O2 saturation.
 Blood Pressure: NIBP (non-invasive), IBP (invasive).Blood Pressure: NIBP (non-invasive), IBP (invasive).
 ± [Capnography].± [Capnography].
 The most critical 2 times during anesthesia are:The most critical 2 times during anesthesia are:
INDUCTIONINDUCTION -- RECOVERYRECOVERY..
 Exactly likeExactly like ““flying a planeflying a plane”” induction (= takeinduction (= take
off) & recovery (= landing). The aim is to achieveoff) & recovery (= landing). The aim is to achieve
aa smoothsmooth induction & ainduction & a smoothsmooth recovery & arecovery & a
smoothsmooth intraoperative course.intraoperative course.

Intraoperative monitoringIntraoperative monitoring :: (1) ECG(1) ECG
ValueValue::
 Heart rate.Heart rate.
 Rhythm (arrhythmias) usually best identified from lead II.Rhythm (arrhythmias) usually best identified from lead II.
 Ischemic changes & ST segment analysis.Ischemic changes & ST segment analysis.
Timing of ECG monitoringTiming of ECG monitoring:: Throughout the surgery: beforeThroughout the surgery: before
induction until after extubation & recovery.induction until after extubation & recovery.
Types & connections of ECG cablesTypes & connections of ECG cables::
 3-leads3-leads:: RRed=ed=RRight Yeight YeLLLLow=ow=LLefteft
BBlack=Alack=Appex (can read leads: I, II, III)ex (can read leads: I, II, III)
 5-leads5-leads:: RRed=ed=RRight Yeight YeLLLLow=ow=LLefteft
Black=under red Green=under yellowBlack=under red Green=under yellow
White=central (can read any of the 12 leads: I, II,White=central (can read any of the 12 leads: I, II,
III, avR, avL, avF, V1-V6).III, avR, avL, avF, V1-V6).

 How to attach ECG electrodes:How to attach ECG electrodes:
 Choose aChoose a bony prominencebony prominence . Avoid fatty. Avoid fatty
regionsregions
 AVOID hairyAVOID hairy areas (up to shaving if required inareas (up to shaving if required in
very hairy persons).very hairy persons).
 Position themPosition them far awayfar away from each other to givefrom each other to give
e higher voltage and better gain.e higher voltage and better gain.
 EnsureEnsure good contactgood contact with the skin: by usingwith the skin: by using
KY-Gel.KY-Gel.
 If the electrodes will not be accessible during theIf the electrodes will not be accessible during the
surgery (eg. on the back in thyroidectomy orsurgery (eg. on the back in thyroidectomy or
breast surgery) or will be soaked in betadine (eg.breast surgery) or will be soaked in betadine (eg.
in abdominal surgery) after ensuring good ECGin abdominal surgery) after ensuring good ECG

If the EGC gives no trace (noiseIf the EGC gives no trace (noise ): follow ECG): follow ECG
cable from the pt to the monitor:cable from the pt to the monitor:
 Ensure good contact with the pt: non-hairy areas,Ensure good contact with the pt: non-hairy areas,
apply KY-Gel, search for slipped or looseapply KY-Gel, search for slipped or loose
electrodes.electrodes.
 Ensure proper fitting of cable connections.Ensure proper fitting of cable connections.
(Sometimes we apply alcohol to dissolve(Sometimes we apply alcohol to dissolve
betadine).betadine).
 Ensure proper fitting of the cable to the monitor.Ensure proper fitting of the cable to the monitor.
 Change monitor settings: try different leads (I, II,Change monitor settings: try different leads (I, II,
III, avR, avR, avL, V1-6), filter, size (amplitude) ofIII, avR, avR, avL, V1-6), filter, size (amplitude) of
ECG.ECG.
 Ensure earthing of the monitor (earth cable fromEnsure earthing of the monitor (earth cable from
behind).behind).

 RULESRULES::
 QRSQRS beep ONbeep ON must be heard at allmust be heard at all
times. NO silent monitors.times. NO silent monitors.
 Remember that yourRemember that your clinicalclinical
judgementjudgement is much more superior to theis much more superior to the
monitor. Check peripheral pulsations.monitor. Check peripheral pulsations.
 Cautery → artefacts & fallacies in ECGCautery → artefacts & fallacies in ECG
(noise/ electrical interference) → check(noise/ electrical interference) → check
radial (peripheral) pulsations.radial (peripheral) pulsations.
 Arrythmias → check radial (peripheral)Arrythmias → check radial (peripheral)
pulsations.pulsations.

Intraoperative monitoringIntraoperative monitoring :: (2) SpO2(2) SpO2
 It is the most important monitor. It gives a LOT ofIt is the most important monitor. It gives a LOT of
information about the pt.information about the pt.
 DefinitionDefinition:: % of oxy-Hb% of oxy-Hb // oxy + deoxy-Hboxy + deoxy-Hb..
 TimingTiming of SpO2 monitoring:of SpO2 monitoring: throughout thethroughout the
surgery: before induction till after extubation &surgery: before induction till after extubation &
recovery. It is therecovery. It is the LASTLAST monitor to be removedmonitor to be removed
off the pt before the pt is transferred outside theoff the pt before the pt is transferred outside the
operating room to recovery room. SpO2operating room to recovery room. SpO2
monitoring should be continued in recovery room.monitoring should be continued in recovery room.
 Waveform of pulse oximeter =Waveform of pulse oximeter =
plethysmographyplethysmography (arterial waveform). It(arterial waveform). It
indicates that the pulse oximeter is reading theindicates that the pulse oximeter is reading the
arterial O2 saturation. Without the waveform pulsearterial O2 saturation. Without the waveform pulse
oximeter readings are unreliable & incorrect.oximeter readings are unreliable & incorrect.

 ValueValue::
 SpO2SpO2: arterial O2 saturation (oxygenation of the pt).: arterial O2 saturation (oxygenation of the pt).
 HRHR..
 Peripheral perfusion statusPeripheral perfusion status (loss of waveform in(loss of waveform in
hypoperfusion states: hypotension & coldhypoperfusion states: hypotension & cold
extremeties).extremeties).
 Gives an idea about theGives an idea about the rhythmrhythm from thefrom the
plethysmography wave (arterial waveform). (Cannotplethysmography wave (arterial waveform). (Cannot
identify the type of arrhythmia but can recognize ifidentify the type of arrhythmia but can recognize if
irregularity is present).irregularity is present).
 Cardiac arrest.Cardiac arrest.
 N.B. Pulse oximeter tone changes withN.B. Pulse oximeter tone changes with
desaturation from high pitched to low pitcheddesaturation from high pitched to low pitched
(deep sound). So just by listening to the monitor(deep sound). So just by listening to the monitor
you can recognize:you can recognize: (1)(1) HRHR (2)(2) O2 saturationO2 saturation..

 How to attach/apply saturation probe:How to attach/apply saturation probe:
 To theTo the fingerfinger oror toetoe (if finger is not(if finger is not
accessible). The red light is applied to theaccessible). The red light is applied to the
nail. Nail polish and stains should be removednail. Nail polish and stains should be removed
→ false readings and artefacts.→ false readings and artefacts.
 Can also be applied to theCan also be applied to the ear lobeear lobe..
 In infants and children can be applied to 2In infants and children can be applied to 2
fingers or to the hand.fingers or to the hand.
 Usually attached to the limb with the IV lineUsually attached to the limb with the IV line
(opposite the limb with the blood pressure(opposite the limb with the blood pressure
cuff).cuff).

ReadingsReadings::
 Normal person on room air (O2 = 21%) ˃Normal person on room air (O2 = 21%) ˃
96%.96%.
 Patient under GA (100% O2) =Patient under GA (100% O2) = 98-100%.98-100%.
 It is not accepted for O2 saturation to ↓It is not accepted for O2 saturation to ↓
belowbelow 96%96% with 100% O2 under GA.with 100% O2 under GA.
Must search for a cause.Must search for a cause.
 < 90%< 90% = hypoxemia.= hypoxemia.
 < 85%< 85% = severe hypoxemia.= severe hypoxemia.

 Fallacies & Inaccuracies occur when:Fallacies & Inaccuracies occur when:
 Misplaced on the pts finger, slipped.Misplaced on the pts finger, slipped.
 Pt movement, shivering.Pt movement, shivering.
 Poor tissue perfusion (cold extremities) →Poor tissue perfusion (cold extremities) →
warm the pt, put a glove filled with warm waterwarm the pt, put a glove filled with warm water
in the pts hand (always avoid hypothermia).in the pts hand (always avoid hypothermia).
 Poor tissue perfusion (hypotension & shock).Poor tissue perfusion (hypotension & shock).
 Cardiac arrest.Cardiac arrest.
 Sometimes by electrical interference fromSometimes by electrical interference from
cautery in some monitors.cautery in some monitors.

RULES:RULES:
 Keep theKeep the soundsound of the pulse oximeterof the pulse oximeter ONON atat
ALL times.ALL times.
 Pay attention to the sound of the pulsePay attention to the sound of the pulse
oximeter.oximeter. NO silentNO silent monitors.monitors.
 ALWAYS Remember that yourALWAYS Remember that your clinicalclinical
judgementjudgement is much more superior to theis much more superior to the
monitor. Check pt colour for cyanosis: lips,monitor. Check pt colour for cyanosis: lips,
nails.nails.
 If hypoxemia occurs immediately check theIf hypoxemia occurs immediately check the
correctcorrect position of the probeposition of the probe on the pt andon the pt and
check the ptscheck the pts colourcolour: nails & lips, then: nails & lips, then
manage accordingly &manage accordingly & CALL 4 HELPCALL 4 HELP..

(3) Blood Pressure(3) Blood Pressure

Intraoperative monitoringIntraoperative monitoring :: (3) BP(3) BP
 NIBPNIBP:: (non-invasive ABP monitoring = automated).(non-invasive ABP monitoring = automated).
Gives readings for: systolic BP, diastolic BP & MAP:Gives readings for: systolic BP, diastolic BP & MAP:
Systolic/ diastolic (mean).Systolic/ diastolic (mean).
 ValueValue:: to avoid and manage extremes of hypotension &to avoid and manage extremes of hypotension &
HTN.HTN. SystolicSystolic BP-BP-DiastolicDiastolic BP-BP- MAPMAP..
 Avoid ↓ MAPAvoid ↓ MAP < 60 mmHg< 60 mmHg (for(for cerebralcerebral && renalrenal
perfusion) & avoid ↓perfusion) & avoid ↓ diastolic pressure < 50 mmHgdiastolic pressure < 50 mmHg
(for(for coronarycoronary perfusion).perfusion).
 Risks of HTN episodes: → (CVS): myocardial ischemia,Risks of HTN episodes: → (CVS): myocardial ischemia,
pulmonary edema, (CNS): hemorrhagic stoke,pulmonary edema, (CNS): hemorrhagic stoke,
hypertensive encephalopathy. While hypotensivehypertensive encephalopathy. While hypotensive
episodes: (CVS): myocardial ischemia, (CNS): ischemicepisodes: (CVS): myocardial ischemia, (CNS): ischemic
stroke, hypoperfusion state metabolic acidosis, delayedstroke, hypoperfusion state metabolic acidosis, delayed
recovery, renal shutdown.recovery, renal shutdown.

 Timing of BP monitoringTiming of BP monitoring : throughout: throughout
the surgery:the surgery: before inductionbefore induction tilltill afterafter
extubation & recovery.extubation & recovery.
 Frequency of measurementFrequency of measurement ::
 By default everyBy default every 55 minutes.minutes.
 EveryEvery 33 minutes: immediately after spinalminutes: immediately after spinal
anesthesia, in conditions of hemodynamicanesthesia, in conditions of hemodynamic
instability, during hypotensive anesthesia.instability, during hypotensive anesthesia.
 EveryEvery 1010 minutes: eg. In awake pts underminutes: eg. In awake pts under
local anesthesia: “local anesthesia: “monitored anesthesia caremonitored anesthesia care””
(minimal hemodynamic changes).(minimal hemodynamic changes).

How to attach/applyHow to attach/apply ::
 Correct cuff sizeCorrect cuff size : width of the cuff should be: width of the cuff should be 1.51.5 times limbtimes limb
diameterdiameter and should occupy at leastand should occupy at least 2/32/3 of the arm.of the arm.
 2 cuff sizes for adult:2 cuff sizes for adult: blueblue: for most adult individuals (60-90 Kg),: for most adult individuals (60-90 Kg),
redred: for morbid obese.: for morbid obese.
 Selection of appropriate cuff size is important because aSelection of appropriate cuff size is important because a titighght cufft cuff
leads toleads to false hifalse highgh readings, while areadings, while a LLoose cuffoose cuff givesgives falsefalse LLowow
readings.readings.

 Is better applied directly to theIs better applied directly to the armarm (remove sleeve).(remove sleeve).
May also be applied to theMay also be applied to the forearmforearm in very obesein very obese
individuals. May be applied to theindividuals. May be applied to the calfcalf if the arms areif the arms are
not accessible during surgery.not accessible during surgery.
 Correct positioningCorrect positioning : cuff is positioned with the hoses: cuff is positioned with the hoses
over theover the brachial arterybrachial artery..
 Usually attached to the limb opposite the IV line & pulseUsually attached to the limb opposite the IV line & pulse
oximeter. Unless the pt is performing hand or arm oroximeter. Unless the pt is performing hand or arm or
breast surgery, the BP cuff is attached with the IV linebreast surgery, the BP cuff is attached with the IV line
and saturation probe on the same side.and saturation probe on the same side.
 AVOIDAVOID attaching it to an arm with A-V graft (for renalattaching it to an arm with A-V graft (for renal
dialysis) → damage of AV graft, & inaccuratedialysis) → damage of AV graft, & inaccurate
measurements.measurements.

Reading Error/failureReading Error/failure ::
 Pressure line is disconnected.Pressure line is disconnected.
 Leakage from damaged cuff.Leakage from damaged cuff.
 Line is compressed (under someone’s footLine is compressed (under someone’s foot
or under a weal).or under a weal).
 Line contains water from washing!Line contains water from washing!
 Monitor error: cuff cannot inflate due toMonitor error: cuff cannot inflate due to
infant or neonate limits.infant or neonate limits.

RULERULE::
 YOURYOUR clinical judgementclinical judgement is always superior to theis always superior to the
monitor. Must checkmonitor. Must check peripheral pulse volumeperipheral pulse volume fromfrom
time to time (Radial A, or Dorsalis Pedis A, or Superficialtime to time (Radial A, or Dorsalis Pedis A, or Superficial
Temporal A) regularly every 10 minutes.Temporal A) regularly every 10 minutes.
 Palpation ofPalpation of Radial ARadial A → systolic BP→ systolic BP ˃ 90˃ 90 mmHg.mmHg.
 Palpation ofPalpation of Dorsalis Pedis ADorsalis Pedis A → systolic BP→ systolic BP ˃ 80˃ 80
mmHg.mmHg.
 Palpation ofPalpation of Superficial Temporal ASuperficial Temporal A → systolic BP ˃→ systolic BP ˃
8080 mmHg.mmHg.
 i.e If Radial A pulsations are lost = systolic BP is < 90i.e If Radial A pulsations are lost = systolic BP is < 90
mmHg.mmHg.
 If dorsalis pedis & superficial temporal pulsations are lostIf dorsalis pedis & superficial temporal pulsations are lost
= systolic BP is < 80 mmHg.= systolic BP is < 80 mmHg.
 Check pt colour forCheck pt colour for pallorpallor: lips, tongue, nails,: lips, tongue, nails,
conjunctiva.conjunctiva.

IBPIBP: (invasive arterial blood pressure monitoring): (invasive arterial blood pressure monitoring)
 It isIt is beat to beatbeat to beat monitoring of ABP via anmonitoring of ABP via an arterialarterial
cannula.cannula.
 Indicated in: major surgeries, during deliberate hypotensiveIndicated in: major surgeries, during deliberate hypotensive
anesthesia, during the use of inotropes, cardiac surgery, inanesthesia, during the use of inotropes, cardiac surgery, in
surgeries involving extreme hemodynamicsurgeries involving extreme hemodynamic
changes/instability eg. pheochromocytoma, repeated ABGchanges/instability eg. pheochromocytoma, repeated ABG
sampling.sampling.

(4) Capnography (CO2)(4) Capnography (CO2)

Intraoperative monitoringIntraoperative monitoring :: (4) CO2(4) CO2
 DefinitionDefinition ::
 What is Capnography?What is Capnography?
 Continuous CO2 measurement displayedContinuous CO2 measurement displayed
as aas a waveformwaveform sampled from thesampled from the
patient’s airway during ventilation.patient’s airway during ventilation.
 What is EtCO2?What is EtCO2?
 AA pointpoint on the capnogram. It is the finalon the capnogram. It is the final
measurement at the endpoint of the ptsmeasurement at the endpoint of the pts
expiration before inspiration begins again.expiration before inspiration begins again.
It is usually the highest CO2 measurementIt is usually the highest CO2 measurement
during ventilation.during ventilation.

 Phases of the capnogram:Phases of the capnogram:
 Balseline:Balseline: A-BA-B
 Upstroke:Upstroke: B-CB-C
 Plateau:Plateau: C-DC-D
 End-tidal:End-tidal: point Dpoint D
 DownstrokeDownstroke

 Normal rangeNormal range:: 30-35 mmHg30-35 mmHg. (Usually lower. (Usually lower
than arterial PaCO2 bythan arterial PaCO2 by 5-6 mmHg5-6 mmHg due todue to
dilution by dead space ventilation).dilution by dead space ventilation).
 ValueValue (data gained from capnography &(data gained from capnography &
ETCO2):ETCO2):
 ETTETT: esophageal intubation.: esophageal intubation.
 VentilationVentilation: hypo & hyperventilation, curare cleft: hypo & hyperventilation, curare cleft
(spontaneous breathing trials).(spontaneous breathing trials).
 Pulmonary perfusionPulmonary perfusion: pulmonary embolism.: pulmonary embolism.
 Breathing circuitBreathing circuit : disconnection, kink, leakage,: disconnection, kink, leakage,
obstruction, unidirectional valve dysfunction,obstruction, unidirectional valve dysfunction,
rebreathing, exhausted soda lime.rebreathing, exhausted soda lime.
 Cardiac arrestCardiac arrest :: adequacy of resuscitation duringadequacy of resuscitation during
cardiac arrest, and prognostic value (outcome aftercardiac arrest, and prognostic value (outcome after
cardiac arrest).cardiac arrest).

Factors affecting EtCO2: what ↑ what ↓Factors affecting EtCO2: what ↑ what ↓
EtCO2?EtCO2?

Individual System MonitoringIndividual System Monitoring
 Position of ETT.Position of ETT.
 Respiratory System.Respiratory System.
 CVS & Hemodynamic Monitoring.CVS & Hemodynamic Monitoring.
 CNS: Awareness.CNS: Awareness.
 Temperature.Temperature.
 Monitoring after Extubation & Recovery.Monitoring after Extubation & Recovery.

(A)(A) Correct Position of ETTCorrect Position of ETT

(A)(A) Correct Position of ETTCorrect Position of ETT
 After intubation Auscultation MUST be done in 5 areas:After intubation Auscultation MUST be done in 5 areas:
►► Rt & Lt infraclavicular.Rt & Lt infraclavicular.
►► Rt & Lt axillary.Rt & Lt axillary.
►► EPIGASTRIUMEPIGASTRIUM: to exclude esophageal intubation.: to exclude esophageal intubation.
 We MUST ALWAYS auscultate the chest after intubationWe MUST ALWAYS auscultate the chest after intubation
for:for:
(1)(1) Equal air entryEqual air entry: to exclude endobronchial: to exclude endobronchial
intubation.intubation.
(2)(2) Adventitious soundsAdventitious sounds : wheezes, crepitations,: wheezes, crepitations,
pulmonary edema.pulmonary edema.
 We MUST ALWAYS auscultate the chest AGAINWe MUST ALWAYS auscultate the chest AGAIN afterafter
repositioningrepositioning to exclude:to exclude:
 InwardInward displacement → endobronchial intubation.displacement → endobronchial intubation.
 OutwardOutward displacement → slippage & accidental extubation.displacement → slippage & accidental extubation.

(B)(B) Respiratory MonitoringRespiratory Monitoring
 Clinical monitoringClinical monitoring ::
 Colour:Colour: cyanosiscyanosis: nails, lips, palms,: nails, lips, palms,
conjunctiva.conjunctiva.
 Chest rise & fall (Chest rise & fall (inflationinflation).).
 VapourVapour in ETT (absent in ventilators within ETT (absent in ventilators with
humdifiers/if filter is used).humdifiers/if filter is used).
 Airway pressureAirway pressure ..
 VentilatorVentilator bellowsbellows (return to full inflation(return to full inflation
during expiratory phase).during expiratory phase).
 VentilatorVentilator soundsound: during resp cycle.: during resp cycle.
Abnormal sounds eg. leakage,Abnormal sounds eg. leakage,
disconnection, high airway pressure, alarms.disconnection, high airway pressure, alarms.

 N.B. Various alarms by the ventilator:N.B. Various alarms by the ventilator:
NEVER ignore an alarm by the ventilator!NEVER ignore an alarm by the ventilator!
 Low airway pressureLow airway pressure: leakage,: leakage,
disconnection.disconnection.
 High airway pressureHigh airway pressure: kink, biting of the: kink, biting of the
tube, bronchospasm, slipped → esophagus.tube, bronchospasm, slipped → esophagus.
 Low expired tidal volumeLow expired tidal volume: leakage.: leakage.
 Apnea alarmApnea alarm: disconnection.: disconnection.
 O2 sensor failureO2 sensor failure: (unfortunately common in: (unfortunately common in
many of our ventilators).many of our ventilators).
 Flow sensor failureFlow sensor failure: (unfortunately common: (unfortunately common
in many of our ventilators).in many of our ventilators).

Respiratory MonitorsRespiratory Monitors ::
 O2 Saturation.O2 Saturation.
 Capnography EtCO2.Capnography EtCO2.
 Airway pressure.Airway pressure.
 ABG samples.ABG samples.

(C)(C) CVS Hemodynamic MonitoringCVS Hemodynamic Monitoring
Clinical monitoringClinical monitoring ::
 ColourColour:: pallorpallor (lips, tongue, nails) = anemia, shock.(lips, tongue, nails) = anemia, shock.
 PalpatePalpate peripheral pulsationsperipheral pulsations every 10 minutesevery 10 minutes
(Radial A, Dorsalis pedis A, Superficial temporal A).(Radial A, Dorsalis pedis A, Superficial temporal A).
 Capillary refilling timeCapillary refilling time : compress nail bed until it is: compress nail bed until it is
blanched. After release of pressure refilling shouldblanched. After release of pressure refilling should
occur within 2 seconds.occur within 2 seconds. If ˃ 5 seconds = poorIf ˃ 5 seconds = poor
peripheral perfusion/circulation.peripheral perfusion/circulation.
 UOPUOP::
 Values: it is an indicator of:Values: it is an indicator of: 1)1) good hydrationgood hydration 2)2) good tissuegood tissue
(renal) perfusion(renal) perfusion 3)3) good renal function. [Urine is the champagnegood renal function. [Urine is the champagne
of anesthetists and urologists!!].of anesthetists and urologists!!].
 Indications:Indications: 1)1) lengthy surgery ˃ 4 hrslengthy surgery ˃ 4 hrs 2)2) major surgery with majormajor surgery with major
blood lossblood loss 3)3) C-section: to monitor injury to the bladder or ureter.C-section: to monitor injury to the bladder or ureter.
 Normal: 0.5-1 ml/kg/hr.Normal: 0.5-1 ml/kg/hr.
 When the catheter is inserted u must always note theWhen the catheter is inserted u must always note the baselinebaseline
urine volumeurine volume at the start of operation.at the start of operation.

Management of oliguria or anuriaManagement of oliguria or anuria ::
 Check that the line is notCheck that the line is not kinkedkinked oror
disconnecteddisconnected..
 PalpatePalpate the urinary bladder (suprapubicthe urinary bladder (suprapubic
fullness), or ask the surgeon to palpate it.fullness), or ask the surgeon to palpate it.
 Raise BP (MAP ˃ 80 mmHg): renal perfusion.Raise BP (MAP ˃ 80 mmHg): renal perfusion.
 IVIV fluid challengefluid challenge ..
 DiureticsDiuretics..
 N.B. Sometimes trendlenberg position (headN.B. Sometimes trendlenberg position (head
down) causes ↓ UOP. Reversal of this positiondown) causes ↓ UOP. Reversal of this position
results in immediate flow of urine.results in immediate flow of urine.

CVS MonitorsCVS Monitors::
 ECG.ECG.
 Blood pressure (NIBP, IBP).Blood pressure (NIBP, IBP).
 Central Venous Pressure: value:Central Venous Pressure: value:
indicator of:indicator of:
1)1) IV volume.IV volume.
2)2) RV function.RV function.

(D)(D) CNSCNS: Awareness: Awareness
Clinical monitoringClinical monitoring ::
Signs of pt awareness:Signs of pt awareness:
 Movement, grimacing (facial expression).Movement, grimacing (facial expression).
 Pupils dilated.Pupils dilated.
 Lacrimation.Lacrimation.
 Tachycardia.Tachycardia.
 HTN.HTN.
 SweatingSweating:: is always anis always an alarming/warning signalarming/warning sign. Causes:. Causes:
 Awareness.Awareness.
 Hypoglycemia.Hypoglycemia.
 Hypercapnia.Hypercapnia.
 Thyroid storm (thyrotoxic crisis).Thyroid storm (thyrotoxic crisis).
 Fever.Fever.
 Always check theAlways check the concentration of ur vaporizerconcentration of ur vaporizer &&
make sure that urmake sure that ur vaporizer is not emptyvaporizer is not empty (below(below
minimum = gives a concentration lower than adjusted).minimum = gives a concentration lower than adjusted).

(E)(E) Temperature MonitoringTemperature Monitoring
 Clinical monitoringClinical monitoring : ur hands.: ur hands.
 MonitorsMonitors: temperature probe:: temperature probe:
nasopharyngeal, esophageal.nasopharyngeal, esophageal.
 AVOID hypothermiaAVOID hypothermia < 36< 36oo
CC. Why? & How?. Why? & How?
 Especially inEspecially in pediatricspediatrics && geriatricsgeriatrics (extremes(extremes
of age).of age).
 WhyWhy is it necessary to avoid hypothermia?is it necessary to avoid hypothermia?
(complications of hypothermia):(complications of hypothermia):
 Cardiac arrhythmias: VT & cardiac arrest.Cardiac arrhythmias: VT & cardiac arrest.
 Myocardial depression.Myocardial depression.
 Delayed recovery (delays drug metabolism).Delayed recovery (delays drug metabolism).
 Delayed enzymatic drug metabolism.Delayed enzymatic drug metabolism.
 Metabolic acidosis (tissue hypoperfusion → anerobicMetabolic acidosis (tissue hypoperfusion → anerobic
glycolysis → lactic acidosis) & hyperkalemia.glycolysis → lactic acidosis) & hyperkalemia.
 Coagulopathy.Coagulopathy.

(E)(E) Temperature MonitoringTemperature Monitoring
How to avoid hypothermiaHow to avoid hypothermia ::
 Warm IV fluids.Warm IV fluids.
 Intermittently switching off air-Intermittently switching off air-
conditioning esp. towards the endconditioning esp. towards the end
of surgery (of surgery (↑ ambient room temp↑ ambient room temp).).
 Pediatrics: warming blanket.Pediatrics: warming blanket.

(F)(F) Monitoring After Extubation &Monitoring After Extubation &
RecoveryRecovery
 After extubationAfter extubation: immediately: immediately fitfit thethe face maskface mask onon
the pt (with a slight chin lift) and observe the breathingthe pt (with a slight chin lift) and observe the breathing
bag:bag:
 Good regular breathing with adequate tidal volume transmittedGood regular breathing with adequate tidal volume transmitted
to the bag.to the bag.
 No transmission to the bag →No transmission to the bag → respiratory obstructionrespiratory obstruction
(improve ur support), or(improve ur support), or apneaapnea (attempt to awaken ur pt by(attempt to awaken ur pt by
painful stimulus or jaw thrust).painful stimulus or jaw thrust).
 BPBP:: within 20% of baseline.within 20% of baseline.
 SpO2SpO2: ˃ 92%: ˃ 92%
 BreathingBreathing: regular, adequate tidal volume.: regular, adequate tidal volume.
 Muscle powerMuscle power : sustained head elevation for 5: sustained head elevation for 5
seconds, good hand grip, tongue protrusion.seconds, good hand grip, tongue protrusion.
 Level of consciousnessLevel of consciousness : fully conscious = 1) obeying: fully conscious = 1) obeying
orders, 2) eye opening, 3) purposeful movement.orders, 2) eye opening, 3) purposeful movement.
 MOST IMP: Pt MUST be able toMOST IMP: Pt MUST be able to protect his ownprotect his own
airwayairway..

To SummarizeTo Summarize::
““How do I monitor the patient in OR?”How do I monitor the patient in OR?”
The 4 basic monitors displayed on theThe 4 basic monitors displayed on the
screen:screen:
1)1) ECG.ECG.
2)2) BP.BP.
3)3) SpO2.SpO2.
4)4) ± Capnogram± Capnogram (EtCO2).(EtCO2).

Normal target values for an adult under GANormal target values for an adult under GA::
 HRHR:: 60-90 (˃ 90 = tachycardia. < 60 =60-90 (˃ 90 = tachycardia. < 60 =
bradycardia).bradycardia).
 BPBP:: 90/60 – 140/90. MAP ˃ 60 mmHg90/60 – 140/90. MAP ˃ 60 mmHg
(cerebral & renal autoregulation).(cerebral & renal autoregulation).
Diastolic BP ˃ 50 mmHg (coronaryDiastolic BP ˃ 50 mmHg (coronary
perfusion pressure).perfusion pressure).
 SpO2SpO2 ˃ 96% on 100% O2.˃ 96% on 100% O2.
 EtCO2EtCO2 = 30-35 mmHg.= 30-35 mmHg.

LISTENLISTEN
 ListenListen to the monitorto the monitor the whole timethe whole time ::
 To theTo the pulse oximeterpulse oximeter tone to identify:tone to identify: 1-1-
Heart rateHeart rate 2-2- O2 saturationO2 saturation from thefrom the
tone (pitch) of pulse oximeter.tone (pitch) of pulse oximeter.
 To the sound of theTo the sound of the ventilatorventilator, to any, to any
abnormal sounds, any alarms.abnormal sounds, any alarms.
 RULERULE:: NO silentNO silent monitors.monitors. ALWAYSALWAYS
keep thekeep the HR sound onHR sound on. If ur monitor is. If ur monitor is
silent (sound is not working) u have tosilent (sound is not working) u have to
look at your monitor the WHOLE time.look at your monitor the WHOLE time.

LLööööKK
 EveryEvery 55 minutesminutes to note the newto note the new BPBP
reading.reading.
 If there is anyIf there is any change in the tonechange in the tone ofof
the pulse oximeter.the pulse oximeter.
 If there is anyIf there is any irregularity in heartirregularity in heart
raterate & during the use of diathermy.& during the use of diathermy.

Clinical CheckClinical Check // 1010 minutesminutes
1)1) Chest inflationChest inflation..
2)2) Ventilator bellowsVentilator bellows: descend and return to become fully: descend and return to become fully
inflated.inflated.
3)3) Airway pressureAirway pressure..
4)4) PalpatePalpate peripheral pulsationsperipheral pulsations (radial A, or dorsalis pedis(radial A, or dorsalis pedis
A, or superficial temporal A):A, or superficial temporal A):
 For pulse volume.For pulse volume.
 During the use of cautery.During the use of cautery.
 In doubt of ECG rhythm (arrythmias).In doubt of ECG rhythm (arrythmias).
 In case monitor or ECG disconnected.In case monitor or ECG disconnected.
5)5) PtPt colourcolour (nails): cyanosis, pallor.(nails): cyanosis, pallor.
6)6) VaporizerVaporizer::
a)a) CheckCheck concentrationconcentration opened.opened.
b)b) LevelLevel of the volatile agent (if needs to be filled).of the volatile agent (if needs to be filled).

RULESRULES NEVER to FORGET:NEVER to FORGET:
 NeverNever start induction with a missing monitor: ECG,start induction with a missing monitor: ECG,
BP, SpO2.BP, SpO2.
 NeverNever remove any monitors before extubation &remove any monitors before extubation &
recovery.recovery.
 NEVERNEVER ignore an alarm by the ventilator.ignore an alarm by the ventilator.
 ALWAYSALWAYS remember than urremember than ur clinical senseclinical sense &&
judgement is better than & superior to any monitor. Ujudgement is better than & superior to any monitor. U
are a doctor u are not a robot. The monitor is presentare a doctor u are not a robot. The monitor is present
to help u not to be ignored and not to cancel ur brain.to help u not to be ignored and not to cancel ur brain.
 Last but by no means least:Last but by no means least:
 ALWAYSALWAYS remember that there is NO such thing asremember that there is NO such thing as
““all monitors disconnected”all monitors disconnected” →→ check that ur pt ischeck that ur pt is
ALIVEALIVE!! Immediately check!! Immediately check peripheralperipheral && carotidcarotid
pulsationspulsations to make sure that ur pt is notto make sure that ur pt is not
ARRESTEDARRESTED!! Once u have ensured pt safety!! Once u have ensured pt safety
reattach ur monitors once again.reattach ur monitors once again.

intraoperative monitoring

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