NBE presentation

1. Role of Capnography
in Emergency Room
Dr.Venugopalan P P
Director and Lead consultant in Emergency Medicine
Aster DM Healthcare
PG Teacher -NBE

2. This session…..
• What is Capnography
• Basic science
• Equipment
• Waveform and interpretation
• Clinical uses in Pre-hospital care and emergency room

3. What is capography?
Capnography refers to the noninvasive
measurement of the partial pressure of
carbon dioxide (CO2) in exhaled breath
expressed as the CO2 concentration over
time.
Relationship of CO2 concentration to time is
graphically represented by the CO2
waveform, or capnogram

6. Capnography
Changes in the shape of the capnogram
are diagnostic of disease conditions
Changes in endtidal CO2 (EtCO2)(the
maximum CO2 concentration at the end of
each tidal breath)can be used to assess
disease severity and response to treatment.
Capnography is also the most reliable
indicator that an endotracheal tube is
placement in the trachea

7. Oxygenation and Ventilation
Must be assessed in both intubated and spontaneously
breathing patients.
• Pulse oximetry provides instantaneous feedback about
oxygenation
• Capnography provides instantaneous informations
1. Ventilation (how effectively CO2 is being eliminated by
the pulmonary system)
2. Perfusion (how effectively CO2 is being transported
through the vascular system)
3. Metabolism (how effectively CO2 is being produced by
cellular metabolism).

10. Capnography- Part of
standard care
Routine part of anesthesia practice in
Europe in the 1970s and in the United
States in the 1980s.
Now part of the standard of care for all
patients receiving general anesthesia
An emerging standard of care in
emergency medical services,
emergency medicine, and intensive
care.

12. How does it works ?
Capnography uses infrared (IR) radiation to make
measurements.
Molecules of CO2 absorb IR radiation at a very specific
wavelength (4.26 µm)
The amount of radiation absorbed having a nearly
exponential relation to the CO2 concentration present in
the breath sample.
Detecting these changes in IR radiation levels, using
appropriate photodetectors sensitive in this spectral
region
Calculation of the CO2 concentration in the gas sample

14. Sampling
Carbon dioxide (CO2) monitors
measure gas concentration, or partial
pressure, using one of two
configurations:
1. Main stream
2. Side stream.

15. Main stream
Mainstream devices
measure respiratory gas
directly from the airway
Sensor located on the
airway adapter at the hub of
the endotracheal tube
(ETT).
Accurate , Less response
time
Heavy, Contaminated easily
with secretions
Configured for intubated
patients

16. Side stream
Side stream devices measure
respiratory gas via nasal or
nasal-oral cannula
Aspirating a small sample
from the exhaled breath
through the cannula tubing to
a sensor located inside the
monitor
Light weight, Slow response
time, Not contaminated easily
Configured for both intubated
and non-intubated patients.

17. Side stream
Configured to use high flow rates (around
150 cc/min) or low flow rates (around 50 cc/
min).
Flow rates vary according to the amount of
CO2 needed in the breath sample to obtain
an accurate reading.

18. Side stream systems
Low flow systems
1. Lower occlusion rate (from moisture or patient secretions)
2. Accurate in patients with low tidal volumes
3. Useful in neonates, infants, and adult patients with hypoventilation
and low tidal volume breathing.
4. Resistant to dilution from supplemental oxygen.
High flow systems
1. Sampling at ≥100 cc/min
2. Inaccurate in neonates, infants, young children, and in hypo
ventilating adult patients

19. CO2 monitors
CO2 monitors are either quantitative or
qualitative.
1. Quantitative devices
Measure the precise endtidal CO2 (EtCO2)
Number (Capnometry)
Number and a waveform (Capnography).
2.Qualitative devices
Measure the range in which the EtCO2 falls
(eg, 0 to 10 mmHg or >35 mmHg)

20. Qualitative capnometric device
Colorimetric EtCO2
detector.
A piece of specially treated
litmus paper
Changes color when
exposed to CO2
Purple for EtCO2 <3 mmHg
Tan for 3 to 15 mmHg
Yellow for >15 mmHg

21. Qualitative capnometric device
Primary use is for verification of
ETT placement
Correctly placed ETT in the
trachea will change the color of
the litmus paper from purple to
yellow.
Esophageal Tube placement
will not change the color of the
litmus paper, which will remain
purple

22. Capnogram
Phase 1 (dead space
ventilation, AB) beginning of
exhalation where the dead
space is cleared from the upper
airway.
Phase 2 (ascending phase, B-
C) Rapid rise in carbon dioxide
(CO2) concentration in the
breath stream as the CO2 from
the alveoli reaches the upper
airway.

23. Capnogram
Phase 3 (alveolar plateau, CD)
CO2 concentration reaching a
uniform level in the entire breath
stream from alveolus to nose.
Point D- at the end of the
alveolar plateau - the maximum
CO2 concentration at the end of
the tidal breath -the endtidal
CO2 (EtCO2).
The number that appears on the
monitor display.
Phase 4 (DE) - the inspiratory
cycle.

24. ETCO2
Patients with normal lung
function have characteristic
rectangular capnograms
Narrow gradients between
alveolar CO2 (ie, EtCO2)
and arterial CO2
concentration (PaCO2) of 0
to 5 mmHg.
Gas in the physiologic dead
space accounts for this
normal gradient

25. Obstructive lung disease
Impaired expiratory flow -
more rounded ascending
phase and an upward
slope in the alveolar
plateau
Abnormal lung function
and ventilation perfusion
mismatch, the EtCO2-
PaCO2 gradient widens
depending on the severity
of the lung disease
Hardman JG, Aitkenhead AR. Estimating alveolar dead space from the arterial to endtidal CO(2) gradient: a modeling analysis. Anesth Analg 2003;
97:1846.

26. ETCO2 in abnormal lung
diseases
The EtCO2 in patients
with lung disease is only
useful for assessing
trends in ventilatory
status over time
Isolated EtCO2 values
may or may not correlate
with the PaCO2

27. How to approach CO2 wave
analysis
CO2 is produced in metabolism
and transported via perfusion,
Use the PQRST method to
different types of emergency
calls.
1. Proper
2. Quantity
3. Rate
4. Shape
5. Trending

28. What is meant by PQRST
approach ?
Read PQRST in order
Asking, "What is Proper?"
• Consider what your desired goal is for this patient.
"What is the Quantity?"
"Is that because of the Rate?"
• If so, attempt to correct the rate.
"Is this affecting the Shape?"
• If so, correct the condition causing the irregular shape.
"Is there a Trend?"
• Make sure the trend is stable where you want it, or
improving.
• If not, consider changing your current treatment strategy.

29. Advanced Airway /
Intubation

30. Advanced Airway /
Intubation
P: Ventilation. Confirm
placement of the
advanced airway
device.
Q: Goal is 35-45
mmHg.
R: 10-12 bpm,
ventilated.

31. Advanced Airway /
Intubation
S: Near flat-line of apnea to
normal rounded rectangle
EtCO2 waveform.
• The top of the shape is
irregular (e.g., like two different
EtCO2 waves mashed
together)
• Indicate a problem with tube
placement.
• A leaking cuff, supra glottic
placement, or an endotracheal
tube in the right main stem
bronchus.

32. Advanced Airway /
Intubation
• Shape is produced when
one lung-often the right
lung-ventilates first,
followed by CO2 escaping
from the left lung.
• The waveform takes on a
near-normal shape
• Then the placement of the
advanced airway was
successful

33. Advanced Airway /
Intubation
T: Consistent Q, R and S
with each breath.
• Watch for a sudden
drop indicating
displacement of the
airway device and/or
cardiac arrest.

34. Cardiac Arrest

35. Cardiac Arrest
P: Ventilation and
perfusion.
Confirmation of effective
CPR. Monitoring for
return of spontaneous
circulation (ROSC) or loss
of spontaneous
circulation
Q: Goal is > 10 mmHg
during CPR.
Expect it to be as high as
60 mmHg when ROSC is
achieved
Murphy RA, Bobrow BJ, Spaite DW, et al. Association between prehospital cpr quality and end-tidal carbon dioxide levels in out-of-hospital
cardiac arrest. Prehosp Emerg Care. 2016;20(3):369-377

36. Cardiac arrest
R: 10-12 bpm, ventilated.
S: Rounded low rectangle
EtCO2 waveform during CPR
with a high spike on ROSC.
T: Consistent Q, R and S with
each breath.
Sudden spike indicating
ROSC
Sudden drop indicating
displacement of the airway
device and/or re-occurrence
of cardiac arrest

38. Optimized Ventilation

39. Optimized Ventilation
P: Ventilation.
• Hyperventilation situations such as anxiety
• Hypoventilation states such as opiate overdose, stroke,
seizure, or head injury.
Q: Goal is 35-45 mmHg.
• Control using rate of ventilation.
• EtCO2 is low (i.e., being blown off too fast), begin by assisting
the patient to breathe more slowly or by ventilating at 10-12
bpm.
• EtCO2 is high (i.e., accumulating too much between breaths),
begin by ventilating at a slightly faster rate.
R: Goal is 12-20 bpm for spontaneous respirations ; 10-12 bpm,
for artificial ventilations.

40. Optimized Ventilation
S: Rounded low rectangle
EtCO2 waveform.
Faster ventilation will produce
wave shapes that are narrow or
as tall since rapid exhalation
contains less CO2.
Slower ventilation produces
wave shapes that are wider and
taller as exhalation takes longer
and more CO2 builds up
between breaths
T: Consistent Q, R and S with
each breath trending towards
optimal ventilation

41. Shock

42. Shock
P: Metabolism and perfusion.
• Perfusion decreases and organs go into shock-whether
hypovolemic, cardiogenic, septic or another type
• Less CO2 is produced and delivered to the lungs
• EtCO2 will go down, even at normal ventilation rates
• EtCO2 can help differentiate between a patient who's anxious
and slightly confused and one who has altered mental status
due to hypo perfusion.
• Indicate a patient whose metabolism is significantly reduced
by hypothermia, whether or not it's shock-related.
Q: Goal is 35-45 mmHg.
• EtCO2 < 35 mmHg in the context of shock indicates significant
cardiopulmonary distress and the need for aggressive
treatment
Hunter CL, Silvestri S, Ralls G, et al. A prehospital screening tool utilizing end-tidal carbon dioxide predicts sepsis and severe sepsis. Am J
Emerg Med. 2016;34(5):813-819

43. Shock
R: Goal is 12-20 bpm for spontaneous respirations;
10-12 bpm for artificial ventilations.
• Anxiety and distress can raise the patient's respiratory
rate.
• Likewise, it may cause a provider to ventilate too fast.
• Faster rates will also lower EtCO2
• Increase pulmonary venous pressure
• Decreasing blood return to the heart in a patient who's
already hypo perfusing
Link MS, Berkow LC, Kudenchuk PJ, et al. Part 7: Adult advanced cardiovascular life support: 2015 American Heart Association guidelines
update for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2015;132(18 Suppl 2):S444-464.

44. Shock
S.Rounded low rectangle
EtCO2 waveform.
T: Quantity will
continuously trend down
in shock.
• Rate of ventilations will
increase in early
compensatory shock
• Then decrease in later
non-compensated shock.
• The shape will not change
significantly because of
the shock itself

45. Pulmonary Embolism

46. Pulmonary Embolism
P: Ventilation and perfusion.
• EtCO2 along with other vital
signs can help you identify a
mismatch between ventilation
and perfusion.
Q: Goal is 35-45 mmHg.
• EtCO2 < 35 mmHg in the
presence of a normal respiratory
rate and otherwise normal pulse
and blood pressure may indicate
that ventilation is occurring
• Perfusion isn't as the embolism
is preventing the ventilation from
connecting with the perfusion.
• Ventilation/perfusion mismatch
Gravenstein JS, Jaffe MB, Gravenstein N, et al., editors. Capnography. Cambridge University Press: Cambridge, UK, 2011.

47. Pulmonary Embolism
R: Goal is 12-20 bpm
for spontaneous
respirations; 10-12 bpm
for artificial ventilations.
S: Low, rounded
rectangle
EtCO2 waveform.
T:The quantity will
continuously trend
down as the patient's
hypo perfusion worsens

48. Asthma

49. Obstructed airway

50. Asthma
P: Ventilation.
• The classic "shark's fin" shape
is indicative of obstructive
diseases like asthma
• EtCO2can provide additional
information about your patient
Q: Goal is 35-45 mmHg. The
trend of quantity and rate together
can help indicate if the disease is
in an early or late and
severe stage.
R: Goal is 12-20 bpm for
spontaneous respirations;
10-12 bpm for artificial
ventilations.
DiCorpo JE, Schwester D, Dudley LS, et al. A wave as a window. Using waveform capnography to achieve a bigger physiological patient
picture. JEMS. 2015;40(11):32-35

51. Asthma
S: Slow and uneven emptying of
alveoli will cause the shape to
slowly curve up resembling a
shark's fin instead of the normal
rectangle.
T:
• Early on the trend is likely to be a
shark's fin shape with an
increasing rate and lowering
quantity.
• As hypoxia becomes severe and
the patient begins to get
exhausted, the shark's fin shape
will continue, but the rate will
slow and the quantity will rise
as CO2 builds up.

52. Mechanical obstruction

53. Mechanical obstruction
P: Ventilation. The
"shark's fin" low-
expiratory shape is
present but is "bent"
indicating obstructed
and slowed inhalation as
well.
Q: Goal is 35-45 mmHg.
R: Goal is 12-20 bpm for
spontaneous
respirations; 10-12 bpm
for artificial ventilations.

54. Mechanical obstruction
S:
• Slow and uneven emptying of
alveoli mixed with air from the
anatomical "dead space" will
cause the shape to slowly curve
up
• Phase 4 inhalation is blocked
(e.g., by mucous, a tumor or
foreign body airway obstruction)
T:
• Hypoxia becomes severe and
the patient begins to get
exhausted and the rate will slow
• Quantity will rise as
CO2 builds up.

55. Emphysema or leaking
alveoli in pneumothorax

56. Emphysema or leaking
alveoli in pneumothorax
P: Ventilation.
Emphysema may have so
much damage to their lung
tissue that the shape of their
waveform may "lean in the
wrong direction."
Pneumothorax won't be able
to maintain the plateau of
phase 3 of the EtCO2 wave.
The shape will start high and
then trail off as air leaks from
the lung
High on the left, lower on
the right shape.
Q: Goal is 35-45 mmHg.
Thompson JE, Jaffe MB. Capnographic waveforms in the mechanically ventilated patient. Respir Care.2005;50(1):100-108; discussion
108-109

57. Emphysema or leaking
alveoli in pneumothorax
R: Goal is 12-20 bpm for
spontaneous respirations;
10-12 bpm for artificial
ventilations.
S: Top of rectangle slopes down
from left to right instead of
sloping gradually up.
T:
• Consistent Q, R and S with
each breath as always is our
goal.
• You should watch for and
correct deviations

58. Diabetes

59. Diabetes
P: Ventilation and perfusion.
EtCO2 can aid in differentiation between hypoglycemia and diabetic
ketoacidosis.
Sometimes the difference is obvious, but in other situations, every diagnostic
tool can help.
Q: Goal is 35-45 mmHg.
R: Goal is 12-20 bpm for spontaneous respirations.
A hypoglycemic patient is likely to have a relatively normal rate of respiration.
A patient who's experiencing diabetic keto acidosis will have increased
respirations
Lowering the quantity of CO2.
CO2 in the form of bicarbonate in the blood will be used up by the body trying to
buffer the diabetic ketoacidosis.
Low EtCO2 can help indicate the presence of significant ketoacidosis.
S: Rounded rectangle EtCO2 waveform.
T: Consistent Q, R and S with each breath for hypoglycemia.
A fast rate of respirations and low quantity for DKA.
Bou Chebl R, Madden B, Belsky J, et al. Diagnostic value of end tidal capnography in patients with hyperglycemia in the emergency
department. BMC Emerg Med. 2016;16:7.

60. Obesity and pregnancy

61. Obesity and pregnancy
P: Ventilation.
Patients with poor lung compliance, obese patients
and pregnant patients may exhibit a particular wave
shape that may indicate that they're highly sensitive
on adequate ventilation.
Q: Goal is 35-45 mmHg.
R: Goal is 12-20 bpm for spontaneous respirations;
10-12 bpm for artificial ventilations.
Yartsev A. (Sep. 15, 2015.) Abnormal capnography waveforms and their interpretation. Deranged Physiology.Retrieved May 20, 2017, from
www.derangedphysiology.com/main/core-topics-
intensive-care/mechanical-ventilation-0/Chapter%205.1.7/abnormal-capnography-waveforms-and-their-interpretation.

62. Obesity and pregnancy
S:
• Rounded low rectangle
EtCO2 waveform
• A sharp increase in the angle of
phase 3 that looks like a small
uptick or "pig tail" on the
righthand side of the rectangle
• CO2 being squeezed out of the
alveoli by the poorly compliant lung
tissue, obese chest wall, or
pregnant belly
• Weight closes off the small bronchi.
• Patients are progress quickly from
respiratory distress to respiratory
failure.
T: Consistent Q, R and S with each
breath

63. Fighting with ventilator or
weaning out of relaxants

65. Rebreathing

66. Ventilator or breathing circuit related

67. Ventilator or breathing circuit related

68. Ventilator or breathing circuit related

69. Ventilator or breathing circuit related

71. CLINICAL APPLICATIONS FOR INTUBATED
PATIENTS
Verification of endotracheal tube (ETT)
placement
Continuous monitoring of tube location
during transport
Gauging effectiveness of resuscitation
and prognosis during cardiac arrest
Indicator of ROSC during chest
compressions

72. CLINICAL APPLICATIONS FOR INTUBATED
PATIENTS
Titrating end tidal carbon dioxide
(EtCO2) levels in patients with
suspected increases in intracranial
pressure
Determining prognosis in trauma
Determining adequacy of ventilation

73. CLINICAL APPLICATIONS FOR
SPONTANEOUSLY BREATHING
PATIENTS
Spontaneously breathing, non intubated patient capnography can
be used for:
Performing rapid assessment of critically ill or seizing patients
Determining response to treatment in acute respiratory distress
Determining adequacy of ventilation in obtunded or
unconscious patients, or in patients undergoing procedural
sedation
Detecting metabolic acidosis in diabetic patients and in
children with gastroenteritis
Providing prognostic indicators in patients with sepsis or septic
shock

74. ETCO2 - Practice Tips
For EPs, Intensivists and
Anaesthesiologists

75. Flat ETCO2 trace
•Ventilator disconnection
•Airway misplaced – extubation,
oesophageal intubation
•Capnograph not connected to circuit
•Respiratory/Cardiac arrest
•Apnoea test in brain death dead
patient
•Capnongraphy obstruction

76. Sudden drop in ETCO2 to
Zero
•Kinked ET tube
•CO2 analyzer
defective
•Total
disconnection
•Ventilator
defective

77. Sudden change in Base line
[Not to zero]
•Calibration error
•CO2 absorber saturated
(check capnograph with room
air)
•Water drops in analyzer or
condensation in airway adapter

78. Sudden increase in ETCO2
•ROSC during
cardiac arrest
•Correction of
ET tube
obstruction

79. Elevated inspiratory
Baseline
• CO2 rebreathing (e.g. soda lime
exhaustion)
• Contamination of CO2 monitor (sudden
elevation of base line and top line)
• Inspiratory valve malfunction
(elevation of the base line,
prolongation of down stroke,
prolongation of phase III)

80. Identify
Capnographic waves
http://www.capnography.com/capnograhs/intrepretation

81. Air-leak - Loose connection between sampling tube
and capnograph / broken connection or filter.

82. Rebreathing capnogram of Mapleson D
circuit.Bain circuit.

83. Cardiogenic oscillations - Ripple effect -
Seen during low frequency ventilation

84. Contamination of capnograph
Trend showing abrupt elevation of
baseline and capnogram

85. Trend capnogram during cardiac arrest /
resuscitation.

86. Upward slanting of phase 4. A normal
variant in pregnant women during
anesthesia.

87. Trend showing gradual elevation of
baseline.
Rebreathing

88. Curare cleft

89. Resembling curare cleft due to an artifact
1. Created by surgeon leaning on the chest,
2. Pushing against the diaphragm during expiration.
3. Partial disconnect of main stream capnometer

90. Dilution of expiratory gases by the forward flow of fresh
gases during the later part of expiration when expiratory
flow rate decreases below the forward gas flow rate

91. Hypothermia

92. Occasionally, there can be a reverse phase 3 slope seen in patients
with emphysema.
Most like this may be due to destruction of alveolar capillary system in
emphysematous lungs resulting in the delivery of carbon dioxide to
expired gases.

93. Endobronchial intubation may not result in a
characteristic waveform. However, occasionally, it
may be like the one seen in COPD or the above.

94. CO2 waveform has two humps. Kypho -
scoliosis resulted in a compression of the
right lung. Differential lung emptying

95. 40
Flatlines

96. Ventilator IMV breath during
spontaneous ventilation

97. Sticking inspiratory valve - Inspiratory
flip - Red indicates possible rebreathing

98. Air leak due to a broken connection
between sampling tube and capnograph

99. Transplanted lung

100. Single lung transplant
Biphasic capnogram recorded in a
patient after single lung
transplantation.
Due to different populations of alveoli.
The first peak represents expired
carbon dioxide from allografted lung,
which has normal compliance, good
perfusion, and good ventilation-
perfusion ratios (V/Q).
The second peak most likely reflects
expired carbon dioxide from the native
lung, because of slanted upstroke or
steeper plateau is characteristic of the
mismatched V/Q ratios

101. Malignant hyperthermimia

102. Spontaneous breathing -
Adult

103. Children and neonates-variations are normal and due to
faster respiratory rates, smaller tidal volumes, relatively
longer response time of the capnographs

105. Pig tail Capnogram
Tripati M, Pandey M. Atypical "tails up" capnogram due to breach in the sampling tube of side-stream capnometer. J Clin Monit 2000;16:17-20.
Slit sampling tube can result
in a pig tail capnogram
A terminal upswing at the end of phase 3,
known as phase 4,
can occur in pregnant subjects,
obese subjects and low compliance states

106. Esophageal intubation

107. Carbonated beverages in the stomach
can result in abnormal capnograms
with progressively decreasing
CO2 values following esophageal
intubation

108. Hyperventilation

109. Elevation of base line
A classic representation of rebreathing.
Exhausted CO2 absorber

110. Expiratory valve malfunction can result in
prolonged abnormal phase 2 and phase 0
Inspiratory valve malfunction predominantly results in
abnormal phase 0

111. Unrecognized exhaustion of
CO2 absorber resulted in substantial
rebreathing and rising ETCO2 values.
The closed circuit without functioning
absorber mimicked Mapleson D circuit

112. Contamination of capnometer results in the
sudden elevation of base line as well as
ETCO2 values

113. Hypoventilation
Rebreathing

114. –drvenugopalpp@gmail.com
“Thanks a lot .”
www.drvenu.blogspot.in
Rate of removal > Rate of Delivery = Hypocapnia