CAPNOGRAPHY

UNION HOSPITAL EMERGENCY DEPARTMENT

KELLY MILLS RN CEN

History of capnography

Used by anesthesiologists since the 1970s

Standard of care in the OR since 1991 New recommendations and JCAHO

standards now expanding utilization in other areas specifically for procedural sedation.

Indications for Use -End-Tidal CO2 Monitoring

Validation of proper endotracheal tube placement

Detection and Monitoring of Respiratory depression

Hypoventilation Obstructive sleep apnea Procedural sedation Adjustment of parameter settings in

mechanically ventilated patients

Definition of Capnography

A numerical value of the EtCO2 AND A waveform of the concentration of CO2 present in the airway

Respiratory rate detected from the actual airflow

Capnometer A Capnometer provides only a

numerical measurement of carbon dioxide.

Capnogram A Capnogram is a waveform

display of carbon dioxide over time

Oxygenation and Ventilation

What is the difference?

Oxygenation Measured by pulse oximetry

(SpO2) Noninvasive measurement Percentage of oxygen in red blood

cells Changes in ventilation take

minutes to be detected Affected by motion artifact, poor

perfusion, etc.

Ventilation Measured by the end-tidal CO2 Partial pressure (mm Hg) or

volume(% vol) of CO2 in the airway at the end of exhalation

Breath-to-breath measurement provides information within seconds

Not affected by motion artifact , poor perfusion, etc.

Oxygenation and Ventilation Respiratory Cycle

= separate physiologic processes:

Oxygenation Ventilation

Comparing Capnography with Pulse Oximetry Capnography Carbon dioxide Reflects ventilation Hypoventilation /

apnea detected immediately

Reflects change in ventilation within 10 seconds

Should be used with pulse oximetry

Pulse oximetry Oxygen saturation Reflects oxygenation SpO2 changes lag

when patient is hypoventilating or apneic

Reflects change in oxygenation within 5 minutes

Should be used with capnography

Respiration–The BIG Picture

Physiological Factors Affecting ETCO2 Levels

Normal Arterial & ETCO2 Values

Physiology Relationship between CO2 and RR

› RR CO2 Hyperventilation

› RR CO2 Hypoventilation

There is an inverse relationship between your respiratory rate and your CO2 level.

As you breath faster your RR goes up, your body is unable to hold onto CO2 and therefore blows it off faster so those levels go down.

As you breath more slowly, your RR goes down, your body is holding more CO2 due to the lack of breaths taken and the CO2 level goes up.

Elements of a Waveform

Alveolar gas mixes with dead space

Alveolar Gas

End of exhalation

Inspiration

The Normal CO2 Waveform

A – B BaselineB – C Expiratory UpstrokeC – D Expiratory PlateauD ETCO2 valueD – E Inspiration begins

ETT

•A normal capnogram is the best evidence that the ETT is correctly positioned•With an esophageal tube little or no CO2 is present

Hypoventilation(increase in ETCO2)

Possible causes:Decrease in respiratory rateDecrease in tidal volumeIncrease in metabolic rateRapid rise in body temperature

(hypothermia)

Waveform: Regular Shape, Plateau Above Normal

• Indicates increase in ETCO2 Hypoventilation Respiratory depressant drugs Increased metabolismFever, pain, shivering

• Interventions Adjust ventilation rate Decrease respiratory depressant drug dosages Assess pain management Conserve body heat

Hyperventilation(decrease in ETCO2)

Possible causes:Increase in respiratory rateIncrease in tidal volumeDecrease in metabolic rateFall in body temperature (hyperthermia)

Waveform: Regular Shape, Plateau Below Normal

• Indicates CO2 deficiency Hyperventilation Decreased pulmonary perfusion Hypothermia Decreased metabolism

• Interventions Adjust ventilation rate Evaluate for adequate sedation Evaluate anxiety Conserve body heat

Obstruction-Shark Fin

Possible causes:Partially kinked or occluded artificial

airwayPresence of foreign body in the airwayObstruction in expiratory limb of the

breathing circuitBronchospasm-Can indicate need for

bronchodilators.

Sudden Loss of Waveform

ApneaAirway ObstructionDislodged airway (esophageal)Airway disconnectionVentilator malfunctionCardiac Arrest

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

TroubleshootingSudden increase in EtCO2

Malignant HyperthermiaVentilation of previously unventilated lungIncrease of blood pressureRelease of tourniquetBicarb causes a temporary <2 minute rise in ETCO2

TroubleshootingEtCO2 values drop to 0

Extubation/Movement into hypopharynxVentilator disconnection or failureEtCO2 defectETT kink

TroubleshootingSudden decrease EtCO2 (not to 0)

Leak or obstruction in systemPartial disconnectPartial airway obstruction (secretions)High-dose epi can cause a decrease

TroubleshootingContinual, exponential decrease in EtCO2

Pulmonary EmbolismCardiac ArrestSudden hypotension/hypovolemiaSevere hyperventilation

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

MICROSTREAM CAPNOGRAPHY SOLUTIONS

MICROSTREAM CAPNOGRAPHY SOLUTIONS

Small pin holes deliver pillow of oxygen around both nose and mouth Nasal and Oral Sampling

CO2 sampling / O2 delivery for non-intubated patients

Uni-junction™ of sampling ports prevents dilution from nonbreathing source

Increased surface area provides greater sampling accuracy in the presence of low tidal volume

Smart CapnoLine™ Plus O2nasal cannula for CO2 measurement and O2 delivery

O2 delivery method reduces CO2 sampling dilution

–Solution for high flow O2 delivery (works effectively under oxygen delivery mask)

FilterLine® patient interfacesPrevents moisture from entering monitor

Replaces water trap

Capnography in procedural sedation

Accurately monitors RR Monitors adequate ventilation with non-intubated

patients Monitors potential risk of over-sedation resulting in Hypoventilation more effectively than pulse oximetry Early indicator of airway obstruction Early warning of apnea Adds an additional level of patient safety providing

the caregiver with vital information to make accurate assessments and timely interventions for the patient