MSIII Introductory Lectures in Anesthesiology

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MS-III Introductory Lectures in Anesthesiology

• Basic Anesthesia Monitoring in the Operating Room

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• American Society of Anesthesiology (ASA)
  Standards for Basic Intraoperative Monitoring

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University of the Health Sciences
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ASA Standards

• Applies to all anesthesia care except labor and
  pain management
• Certain criteria may be waived in extenuating
  circumstances
• should document circumstances in chart
• potential criteria highlighted in future slides
• Definitions
• Continually - repeated regularly and frequently
• Continuous - without interruption

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Standard I

• Qualified personnel shall be present in the
  operating room throughout all
• General Anesthetics
• Regional Anesthetics
• Monitored Anesthesia Care
• Temporary Absence Exceptions
• hazardous conditions for anesthesia provider
• provide for remote monitoring
• emergency situations

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Standard II

• During all anesthetics the following parameters
  will be continually monitored
• oxygenation
• ventilation
• circulation
• temperature

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Oxygenation

• Objective
• ensure adequate oxygen concentration in inspired
  gas and blood
• Methods
• inspired gas oxygen analyzer with alarms (GA)
• pulse oximetry
• illumination and exposure to assess color

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Pulse Oximetry

• Theory
• two wavelengths (660 and 960 nm)
• calculates functional saturation (physiologic
  saturation)
• Limitations
• dyes or other hemoglobin species (carboxy, met,
  fetal, etc)
• motion
• low perfusion states
• electrocautery
• ambient light

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Pulse Oximetry

• Optical plethysmography
• detects pulsatile changes in blood volume
• Spectrophotometry
• measures pulsatile hemoglobin saturation
• Assumptions
• all pulsation is arterial
• light passes through pulsatile beds

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Ventilation

• Objective
• ensure adequate ventilation of patient
• Methods

• qualitative clinical signs
• chest excursion
• observation of reservoir bag
• auscultation of breath sounds

• quantitative measurement
• end tidal carbon dioxide
• volume of expired gas
• continuous circuit disconnect monitor for
  mechanical ventilation

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University of the Health Sciences
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Ventilation

• General Anesthesia
• qualitative clinical signs adequate
• quantitative methods encouraged
• endotracheal tube or laryngeal mask placement
• continual end tidal carbon dioxide identification
• continuous disconnect alarm mandatory during
  controlled ventilation
• Regional Anesthesia and Monitored Anesthesia Care
• continual qualitative clinical signs (minimum)

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University of the Health Sciences
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Capnography

• Theory
• main or sidestream sampling
• several technical methods available
• IR, raman gas scattering, mass or photoacoustic
  spectroscopy
• Applications
• confirmation of intubation
• monitoring for circuit disconnection
• identification of airway obstruction
• rebreathing/metabolic monitoring

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University of the Health Sciences
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Circulation

• Objective
• ensure adequacy of circulatory function
• Methods
• continuous electrocardiogram monitoring
• arterial blood pressure and heart rate q 5 min
• during GA one additional continual parameter

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Temperature

• Objective
• aid in maintaining appropriate body temperature
• Application
• readily available method to continuously monitor
  temperature if changes are intended, anticipated
  or suspected
• Methods
• thermistor
• temperature sensitive chemical reactions
• location

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Intra-arterial Blood Pressure

• Equipment
• transducer and pressure monitor
• Monitoring location
• upper extremity
• lower extremity
• superficial temporal
• Technique

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Noninvasive Blood Pressure

• Methodology
• oscillometric algorithms
• automated
• reproducible
• Limitations
• cuff size
• oversize erroneously low measurements
• to small erroneously high

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Electrocardiogram

• 3 vs. 5 electrode system
• three versus seven leads for diagnostic purposes
• Heart rate measurement
• R wave counting (any lead)
• Ischemia Monitoring
• lead II and V5 are 90 sensitive
• lead II, V5 and V4 up to 98 sensitive
• Arrhythmia monitoring
• lead II or esophageal for supraventricular
  arrhythmias
• all leads for ventricular arrhythmias

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Neuromuscular FunctionEvaluation of Reversal of
Blockade

• Clinical Criteria
• head lift gt 5 seconds
• sustained hand grip
• negative inspiratory force
• at least -55 cmH2O for adults
• at least -32 cmH2O for children
• vital capacity 15 ml/kg
• absence of nystagmus or diplopia

• Evoked Response Criteria
• 1-2 twitches prior to reversal
• sustained tetanus to 50 Hz supra-maximal stimulus
• no fade on DBS

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Neuromuscular Blockade

• Site of Stimulation
• ulnar vs. facial vs. posterior tibial
• Characteristics of Electrical Stimuli
• supra-maximal, 0.2 msec, square wave
• Patterns of Stimulation

Department of Anesthesiology Uniformed Services
University of the Health Sciences