Patient Monitoring

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Patient Monitoring Minimum Monitoring
Standards
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Monitoring

• Monitor - measuring instrument capable of
  delivering a warning when the variable being
  measured falls outside preset limits
• Augment clinical observations decisions thereby
  reducing morbidity and mortality

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Pitfalls of monitoring

• Over-reliance upon monitors
• Faulty equipment / data
• Complications from invasive monitoring
• Constantly sounding alarms
• Distracts anaesthetist from patient

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Cardiovascular System

• Clinical examination
• Pulse
• Skin colour
• Capillary refill time
• Peripheries
• Urine output gt 0.5 ml/kg

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Cardiovascular System

• Electrocardiography
• 3 lead recording of the hearts electrical
  activity
• Does NOT measure cardiac output
• Measures rate, rhythm and ST segment
• CM5 configuration
• May be affected by
• Diathermy
• Increased thoracic wall thickness
• Poor electrode contact

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Cardiovascular System

• Pulse Oximetry
• Measures pulse and Hb oxygen saturation
• Probe contains 2 LEDs and sensor
• Uses wavelengths of light able which have
  different absorption by Hb, according to
  oxygenation
• LED rapidly turned on and off, producing waveform
  (8 beats), inducing delay
• Fixed component of absorption removed leaving a
  variable pulsatile arterial waveform
• Successive beats averaged, calculating Rx every 8
  sec

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Cardiovascular System

• Pulse Oximetry
• Problems
• Poor measure of ventilation
• Highlights desaturation after hypoxia occurred
• Affected by
• Decreased peripheral pulsation
• Abnormal Hb molecules
• Artificial pigments / very bright light

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Cardiovascular System

• Non-invasive blood pressure
• Palpation / auscultation
• Automated oscillometer
• Cuff inflated and deflated progressively
• Small pressure changes detected as blood flows
• Automated to read at set intervals
• Disadv Delay measurement/ inaccuracy lt60/
  discomfort/ skin or nerve damage / delay iv
  drugs/ SpO2 malfunctions

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Cardiovascular System

• Direct (Invasive) BP measurement
• Cannulation of artery (Direct /Seldinger)
• Pressure transducer (zeroed at pts heart level)
• Info HR, art waveform, systolic, diastolic and
  MAP
• Advantages
• Accurate (esp. at low pressure)
• Beat-to-beat changes
• Obtain freq. arterial blood samples
• Disadvantages
• Bleeding
• Arterial damage / thrombosis / distal ischaemia
• Sepsis
• Inadvertent injection of drugs

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Cardiovascular System

• Central Venous Pressure
• Guide fluid replacement
• Long catheters / subclavian / internal jugular
• Complications
• Acute arrhythmias, bleeding, pneumothorax,
  damage to mediastinal structures, embolization
• Delayed sepsis, thrombosis, cardiac rupture

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Cardiovascular System

• Pulmonary Artery Pressure
• Info on left ventricle filling pressure
• Pulmonary art. floatation catheter - 3 lumens
• Distal lumen pressure transducer gt waveform
• Lumen for balloon inflation
• Proximal lumen for CO measurement
• Sterile flexible sheath
• Complications
• Acute arrhythmias, bleeding, damage to lungs or
  vessels
• Chronic sepsis, embolization, valve damage,
  cardiac rupture

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Cardiovascular System

• Cardiac Output
• Thermodilution gold standard
• Transthoracic / transoesophageal doppler
• Transthoracic impedance monitors
• Pulse contour
• Transoesophageal echocardiography

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Respiratory System

• Clinical examination
• Cyanosis
• Respiratory rate
• Chest / reservoir bag movement
• Auscultation

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Respiratory System

• Airway pressure
• Measured in pts receiving IPPV
• Cause barotrauma / reduce CO
• Causes of increased pressure
• Increased lung compliance
• Thoracic compliance
• Equipment problem
• Causes of decreased pressure
• disconnection

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Respiratory System

• Disconnection alarm
• Tidal Volume
• Confirms ventilation
• Allows optimisation of ventilator settings
• Measured by spirometers

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Respiratory System

• Oxygen Delivery
• Oxygen failure alarm
• Oxygen analyser
• Galvanic (fuel cell) O2 analyser
• Measures PaO2 and generates current by redn of O2
  at silver cathode connected through thin film of
  electrolyte soln
• Placed in inspiratory limb of breathing system

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Respiratory System

• Capnography
• Infrared absorption spectrophotometry
• Extent of IR absorption by CO2 is measured as a
  reduction in heat generated at detector
• Useful in
• Correct placement of tube
• Adequacy of ventilation / effects of IPPV
• Detect rebreathing
• Detect MH, PE,
• Maintaining normocapnia

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Respiratory System

• Anaesthetic vapour delivery
• Infrared analysers
• Quartz crystal oscillators
• Mass spectrometer

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Nervous System

• Clinical
• Estimation of depth of unconsciousness
• Signs of sympathetic over-activity
• Lacrimation
• Sweating
• Pupillary dilatation
• Increase in HR / BP

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Nervous System

• Cerebral Function Monitor
• Types
• Isolated forearm technique
• EEG
• Respiratory sinus arrhythmia
• Auditory evoked potentials
• Uses
• Avoidance of awareness
• Controlling sedation
• Carotid art anaesthesia
• Hypotensive anaesthesia
• Tx of epilepsy

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Metabolism

• Temperature
• Fluid and electrolyte status
• Blood gas, acid-base status
• Blood Hb and coagulation status
• Blood glucose

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Minimum Monitoring Standards

• Recommendations by AAGBI (2000)
• Trained / experienced anaesthetist present
• Responsibility of anaesthetist to
• Check anaesthetic equipment
• Ensure familiarity with equipment
• Set appropriate alarms (incl. infusion devices)

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Minimum Monitoring Standards

• Essential monitoring in every case
• Oxygen analyser with audible alarm
• Airway pressure alarm
• Vapour analyser
• SpO2
• ECG
• NIBP
• Capnography
• Nerve stimulator if relaxant used
• Temperature measurement available
• Same standards for LA / sedation cases

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Minimum Monitoring Standards

• Induction
• SpO2 / ECG / NIBP / Capnography
• Availability of nerve stimulator / temp probe
• Maintenance
• As for induction ( vapour analyser)
• Recovery
• Monitored until fully recovered
• SpO2 / NIBP
• Immediate availability of ECG, capnography, nerve
  stimulator, temp probe
• Transfer