Capnography: The Ventilation Vital Sign

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CapnographyThe Ventilation Vital Sign

• ESCAMBIA COUNTY EMS

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Objectives

• Define capnography
• Discuss respiratory cycle
• Discuss ways to collect ETCO2 information
• Discuss non-intubated vs. intubated patient uses
• Discuss different waveforms and treatments of
  them.

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So what is Capnograhy?

• Capnography- Continuous analysis and recording of
  carbon dioxide concentrations in respiratory
  gases ( I.E. waveforms and numbers)
• Capnometry- Analysis only of the gases no
  waveforms

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Respiratory Cycle

• Breathing - Process of moving oxygen into the
  body and CO2 out can be passive or non-passive.
• Metabolism - Process by which an organism obtains
  energy by reacting O2 with glucose to obtain
  energy.
• Aerobic- glucoseO2 water vapor, carbon
  dioxide, energy (2380 kJ)
• Anaerobic- glucose alcohol, carbon dioxide,
  water vapor, energy (118 kJ)

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Respiratory Cycle cont.

• Ventilation - Rate that gases enters and leaves
  the lungs.
• Minute ventilation - Total volume of gas entering
  lungs per minute
• Alveolar Ventilation - Volume of gas that reaches
  the alveoli
• Dead Space Ventilation - Volume of gas that does
  not reach the respiratory portions ( 150 ml)

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Respiratory Cycle
Oxygen -gt lungs -gt alveoli -gt blood
Oxygen
breath
CO2
muscles organs
lungs
Oxygen
CO2
cells
energy
blood
Oxygen Glucose
CO2
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EtCO2 Monitoring

• Carbon dioxide is a colorless, odorless gas
• Concentration in air 0.03
• CO2 produced by cell metabolism
• Transported from cell in three forms
• 65 as bicarb following conversion
• 25 bound to blood proteins (hemoglobin)
• 10 in plasma solution
• PaCO2 reflects plasma solution

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EtCO2 Monitoring
The heart pumps freshly oxygenated blood
throughout the body to cells where oxygen is
consumed (metabolism). Carbon dioxide, produced
as a byproduct, diffuses out of cells into the
vascular system.
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EtCO2 Monitoring

• Carbon dioxide-rich blood is then pumped through
  the
• pulmonary capillary bed where the carbon dioxide
• diffuses across the alveolar capillary membrane
  and
• is exhaled via the nose or mouth.

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Respiratory Cycle
ALL THREE ARE IMPORTANT!
PERFUSION
VENTILATION
METABOLISM
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How is ETCO2 Measured?

• Semi-quantitative capnometry
• Quantitative capnometry
• Wave-form capnography

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Quantitative Capnometry

• Absorption of infra-red light
• Gas source
• Side stream
• In-line
• Factors in choosing device
• Warm up time
• Cost
• Portability

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EtCO2 Monitoring

• In sidestream capnographs the exhaled CO2 is
  aspirated via ETT, cannula, or mask through a
  510 foot long sampling tube connected to the
  instrument for analysis this method is intended
  for the non-intubated patient.
• Both mainstream and sidestream technologies
  calculate the CO2 value and waveform.

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EtCO2 Monitoring

• Decreased EtCO2
• Increased CO2 Clearance
• Hyperventilation
• Decreased CO2 production
• Hypothermia
• Sedation
• Paralysis
• Decreased Delivery to Lungs
• Decreased cardiac output
• V/Q Mismatch
• Ventilating non-perfused lungs (pulmonary
  edema)

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EtCO2 Monitoring

• Ventilation/Perfusion Ratio (V/Q)
• Effective pulmonary gas exchange depends
  on balanced V/Q ratio
• Alveolar Dead Space (atelectasis/pneumonia)
  (V gt Q ? CO2 content)
• Shunting (blood bypasses alveoli w/o picking up
  o2) (V lt Q ? CO2 content)
• 2 types of shunting
• Anatomical blood moves from right to left
  heart w/o passing through lungs (congenital)
• Physiological blood shunts past alveoli w/o
  picking up o2

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EtCO2 Monitoring
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EtCO2 Monitoring

• Ventilation/Perfusion Ratio (V/Q)
• V/Q Mismatch
• Inadequate ventilation, perfusion or both
• Three types
• Physiological Shunt (VltQ)
• Blood passes alveoli
• Severe hypoxia w/ gt 20 bypassed blood
• Pneumonia, atelectasis, tumor, mucous plug
• Alveolar Dead Space (VgtQ)
• Inadequate perfusion exists
• Pulmonary Embolus, Cardiogenic shock, mechanical
  ventilation w/ ? tidal volumes
• Silent Unit (? V ? Q)
• Both ventilation perfusion are decreased
• Pneumothorax ARDS

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EtCO2 Monitoring
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EtCO2 Monitoring
More Air Less Blood V gt Q
Equal Air and Blood V Q
More Blood Less Air V lt Q
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EtCO2 Monitoring

• Components of the normal capnogram

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EtCO2 Monitoring

• A - B describes the respiratory baseline
• It measures the CO2-free gas in the dead space of
  the airways

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EtCO2 Monitoring

• B-C is also known as the expiratory upstroke,
  where alveolar air mixes with dead space air

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EtCO2 Monitoring

• C-D is the expiratory plateau, exhalation of
  mostly alveolar gas (should be straight)
• Point D is the EtCO2 level at the end of a normal
  exhaled breath (35-45mmHg)

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EtCO2 Monitoring

• D-E is inspiration, inhalation of CO2-free gas,
  and rapid return of waveform to baseline

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Waveform Capnometry

• Adds continuous waveform display to the ETCO2
  value.
• Additional information in waveform shape can
  provide clues about causes of poor oxygenation.

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Interpretation of ETCO2
Excellent correlation between ETCO2 and cardiac
output when cardiac output is low. When cardiac
output is near normal, then ETCO2 correlates with
minute volume. Only need to ventilate as often
as a load of CO2 molecules are delivered to the
lungs and exchanged for 02 molecules.
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Hyperventilation Kills
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EtCO2 Values
Normal 35 45 mmHg Hypoventilation gt 45
mmHg Hyperventilation lt 35 mmHg
Wave form
value
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Physiology

• Relationship between CO2 and RR
• ?RR ? ?CO2 Hyperventilation
• ? RR ? ? CO2 Hypoventilation

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Why ETCO2 - I Have My Pulse Ox?

• Pulse Oximetry
• Oxygen saturation
• Reflects oxygenation
• SpO2 changes lag when patient is hypoventilating
  or apneic
• Should be used with capnography

• Capnography
• Carbon dioxide
• Reflects ventilation
• Hypoventilation/
• apnea detected immediately
• Should be used with pulse oximetry

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What does it really do for me?

• Non-Intubated Applications
• Bronchospasms asthma, COPD, anaphlyaxis
• Hypoventilation drugs, stroke, CHF, post-Ictal
• Shock and circulatory compromise
• Hyperventilation Syndrome biofeedback

• Intubated Applications
• Verification of ETT placement
• ETT surveillance during transport
• Control ventilations during CHI and increased ICP
• CPR compression efficacy, early signs of ROSC,
  survival predictor

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The Normal Wave Form
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EtCO2 Monitoring
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EtCO2 Monitoring

• Tracheal vs- Esophageal Intubation

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Normal Wave Form

• Square box waveform
• ETCO2 35-45 mm Hg
• Management monitor patient

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Dislodged ETT

• Loss of waveform
• Loss of ETCO2 reading
• Management follow DOPE mnemonic and replace
  ETT

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Esophageal Intubation

• Absence of waveform
• Absence of ETCO2
• Management re-Intubate

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CPR

• Square box waveform
• ETCO2 10-15 mm Hg (possibly higher) with adequate
  CPR
• Management change rescuers if ETCO2 falls below
  10 mm Hg

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Obstructive Airway

• Shark fin waveform
• With or without prolonged expiratory phase
• Can be seen before actual attack
• Indicative of bronchospasm (asthma, COPD,
  allergic reaction)
• Management bronchodilators (Albuterol, Atrovent,
  or Epinephrine)

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EtCO2 Monitoring

• Asthma and COPD (Contd)
• Waveforms can indicate need for
  bronchodilators (shark fin waveform)

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Obstructive Airway

• With or without prolonged expiratory phase
• Can be seen before actual attack
• Indicative of bronchospasm (asthma, COPD,
  allergic reaction)
• Management bronchodilators (Albuterol, Atrovent,
  or Epinephrine)
• Shark fin waveform

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EtCO2 Monitoring

• Emphysema

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CPR

• Square box waveform
• ETCO2 10-15 mm Hg (possibly higher) with adequate
  CPR
• Management change rescuers if ETCO2 falls below
  10 mm Hg if no autopulse available

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Rising Baseline

• Patient is re-breathing CO2
• Management check equipment for adequate oxygen
  flow
• If patient is intubated allow more time to exhale

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Patient breathing around ETT

• Angled, sloping down stroke on the waveform
• In adults may mean ruptured cuff or tube too
  small
• In pediatrics tube too small
• Management assess patient, oxygenate, ventilate
  and possible re-intubation

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EtCO2 Monitoring

• Pulmonary Embolus
• Note near normal waveform, but angled C-D
  section (indicates alveolar dead space)

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EtCO2 Monitoring

• Esophageal Intubation

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EtCO2 Monitoring

• Esophageal intubation with carbonated beverages

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EtCO2 Monitoring
Head Injury

• EtC02 is very useful in monitoring intubated
  head- injured patients.
• Hyperventilation Hypocapnea ? Cerebral
  Ischemia
• Target end tidal C02 value of 35-38 mmHg

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EtCO2 Monitoring

• Hypothermia

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Hyperventilation

• Ventilations are high and ETCO2 is high consider
  other causes (DKA, sepsis, TCA overdose, acute
  renal failure, methanol Shortened waveform.
• ETCO2 lt 35 mm Hg
• Management if conscious gives biofeedback. If
  ventilating slow ventilations
• If ingestion, salicylate poisoning)

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EtCO2 Monitoring

• Hyperventilation

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Hypoventilation

• Prolonged waveform
• ETCO2 gt45 mm Hg
• Management assist ventilations or intubate as
  needed

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EtCO2 Monitoring

• Hypoventilation

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Curare Cleft

• Curare cleft is when a neuromuscular blockade
  wears off
• The patient takes small breaths that causes the
  cleft
• Management consider neuromuscular blockade
  re-administration

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EtCO2 Monitoring

• Spontaneous respirations in the paralyzed patient
  (Curare cleft)

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EtCO2 Monitoring

• EtCO2 and cardiac output
• Values lt20mmHg unsuccessful resuscitation
• Low (20-30mmHg) good CPR or recovering heart

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EtCO2 Monitoring

• EtCO2 and cardiac output
• Sudden increase in value ROSC

Cardiac arrest survivors had an average ETCO2 of
18mmHg, 20 minutes into an arrest while non
survivors averaged 6. In another study,
survivors averaged 19, and non-survivors 5.
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EtCO2 Monitoring

• Rapid Assessment Triage Tool
• Critically ill patients
• Victims of chemical terrorism
• Obtain ABCs in 15 seconds
• A waveform patent airway
• B waveform graphic representation of
  breathing
• C normal EtCO2 adequate perfusion

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EtCO2 Monitoring

• No motion artifact (uncooperative pt?)
• Reliable in low perfusion states
• Accurate reliable in seizing patients
• Apneic, seizing patient
• No waveform No chest wall movement
• Ineffectively ventilating seizing patient
• Low waveform low EtCO2
• Effectively ventilating seizing patient
• Normal waveform normal EtCO2

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EtCO2 Monitoring

• Capnography in Terror
• Common conditions diagnosed by capnography
• Apnea
• No waveform, no chest wall movement, no breath
  sounds
• Upper respiratory obstruction
• No waveform, chest wall moving, no breath sounds,
  responsive to airway realignment maneuvers
  (waveform returns)
• Laryngospasm
• No waveform, chest wall moving, no breath sounds,
  unresponsive to airway realignment, responds to
  PPV
• Bronchospasm
• shark fin waveform
• Respiratory failure
• Values gt 70 mmHg in pt w/o COPD

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EtCO2 Monitoring
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EtCO2 Monitoring
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EtCO2 Monitoring

• Metabolic States
• Diabetes/Dehydration
• EtCO2 tracks serum HCO3 degree of acidosis (?
  EtcO2 metabolic acidosis)
• Helps to distinguish DKA from NKHHC and
  dehydration

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EtCO2 Monitoring
Troubleshooting
Sudden increase in EtCO2
Malignant Hyperthermia Ventilation of previously
unventilated lung Increase of blood
pressure Release of tourniquet Bicarb causes a
temporary lt2 minute rise in ETCO2
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EtCO2 Monitoring
Troubleshooting
EtCO2 values 0
Extubation/Movement into hypopharynx Ventilator
disconnection or failure EtCO2 defect ETT kink
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EtCO2 Monitoring
Troubleshooting
Sudden decrease EtCO2 (not to 0)
Leak or obstruction in system Partial
disconnect Partial airway obstruction
(secretions) High-dose epi can cause a decrease.
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EtCO2 Monitoring
Troubleshooting
Change in Baseline
Calibration error Mechanical failure Water in
system
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EtCO2 Monitoring
Troubleshooting
Continual, exponential decrease in EtCO2
Pulmonary Embolism Cardiac Arrest Sudden
hypotension/hypovolemia Severe hyperventilation
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EtCO2 Monitoring
Troubleshooting
Gradual increase in EtCO2
Rising body temperature Hypoventilation Partial
airway obstruction (foreign body) Reactive airway
disease
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EtCO2 Monitoring

• No motion artifact (uncooperative pt?)
• Reliable in low perfusion states
• Accurate and reliable in seizing patients
• Apneic, seizing patient
• No waveform No chest wall movement
• Ineffectively ventilating seizing patient
• Low waveform low EtCO2
• Effectively ventilating seizing patient
• Normal waveform normal EtCO2

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Now what does all this mean to me?

• ETCO2 is a great tool to help monitor the
  patients breath to breath status.
• Can help recognize airway obstructions before the
  patient has signs of attacks
• Helps you control the ETCO2 of head injuries
• Can help to identify ROSC in cardiac arrest

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How Do I Document All of This?

• The documentation burdens increase along with the
  litigation
• There should be no unrecognized esophageal
  intubations at any time or place with all the
  technology and cross checks available to the
  provider
• Hypoxic Brain Injury and or Permanent Disability
• OR

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DEATH
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How Do I Document All of This?

• Death usually occurs long after EMS has
  transported to the hospital.
• When questions arise, who gets the blame?
• The Paramedics did it!
• In lawsuits with physicians, nurses and
  hospitals, EMS is viewed as the least trained.
• It is almost always easier for juries to believe
  that the lowest trained person made the mistake.

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How Do I Document All of This?

• Confirming Tube Placement
• Observational Methods
• Direct Visualization
• Tube passes the vocal cords
• Cuff inflation noted beyond the cords
• Observed chest wall movement

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How Do I Document All of This?

• Confirming Tube Placement
• Observational Methods
• Auscultation
• Listen over epigastrum first
• Listen to apex l/r, bases l/r, sternal notch

Extras (1) Misting on exhalation (2) Absence of
gastric contents within the ET
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ABCDs of ET Documentation

• 2 Bs
• Breath Sounds
• Document type and quality of sounds
• Document BBS/CE
• Bowel Sounds
• Document as no sounds noted in epigastrum

• 2 As
• Watched it pass cords
• Cuff inflation pass the vocal cords observed

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ABCDs of ET Documentation

• Big Ds
• Doctor recheck his findings
• Document, Document, Document
• Do it over and over and recheck findings
• Every movement
• When pt does not improve
• Before you enter the ER

• 5 Cs
• Condensation in the tube-noted as misting in the
  tube
• Chest rise-noted as adequate chest rise
• CO2-note as co2 and or the reading
• Centimeter marking-noted as tube at 22mm
• Clinical signs-improvement or decline in patient
  condition

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Final Narrative Documentation

• Example
• Pt ventilated w/BVM 100o2 with ET intubated
  following with passage visualized through the
  cords and with inflation beyond. No breath
  sounds over abdomen, clear and equal breath
  sounds noted in apexes and bases, adequate chest
  rise and misting present, CO2 noted. Tube
  placement noted at 22cm and tube tamer in place
  and secured ET.

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• Many special thanks to
• JEMS Magazine www. jems.com
• Peter Canning, EMT-P emscaphography.blogspot.com
• Dr. Baruch Krauss baruch-krauss_at_tch.harvard.edu
• Bhavani-Shankar Kodali MD www.capnography.com
• Bob Page, AAS, NREMT-P, CCEMT-P
• Steve Berry www.IAmNotAnAmbulanceDriver.com/mm5/m
  erchant.mvc?
• Dr. Reuben Strayer reuben-strayer_at_mail.mcgill.ca
• UTSW/BIOTEL EMS SYSTEM www.utsouthwestern.edu
• Oridion Medical Systems www.oridion.com/global/en
  glish/home.html
• Blogborgymi blogorygmi.blogspot.com
• University of Adelaide, South Australia
  www.health.adelaide.edu.au/paedanaes/talks/co2/cap
  nography.html

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Now we are finished?

• Questions
• Comments
• Concerns
• Snide Remarks
• Applause