TITLE / End Tidal Carbon Dioxide (EtCO2) Monitoring
NUMBER / Last Revised/Reviewed Effective Date: / July, 2012
TJC FUNCTIONS / PC
Applies to / PW
I. /
SCOPE / PURPOSE / POLICY STATEMENT

Capnography is a tool for non-invasively measuring the partial pressure of carbon dioxide at the end of exhalation and directly measures ventilatory performance of the lungs. Carbon dioxide, produced during aerobic metabolism, builds up in the tissues. It diffuses out of the cells, into the circulation and across the alveolar membrane during respiration. It is then excreted by exhalation. Poor ventilation, as a result of sedation, results in a build-up of CO2, which is recognized by the sensor. A decrease in oxygen saturation, as reflected in a drop in the SpO2 displayed by the monitor, is a late indicator of hypoventilation and apnea. EtCO2 monitoring, through capnography, gives an accurate picture of the patient’s ventilatory status.

II. /
QUALIFIED PERSONNEL
  1. Physicians/Licensed Independent Practioner
  2. Registered Nurses (RN) following successful completion of the appropriate competency checklists.
  3. Respiratory Therapist

STANDARD OF CARE

Patients who are at risk for respiratory depression or meet the suggested recommendations for EtCO2 monitoring may benefit from the use of this monitoring.

III. / DEFINITIONS

End Tidal Carbon Dioxide (EtCO2)– Peak concentration of carbon dioxide occurring at the end of expiration. Normal EtCO2 value: 30 – 45 mmHg.

Capnogram: A graphical waveform display of carbon dioxide concentration over time.

Capnometry:Continuous and non-invasive measurement and graphical display of EtCO2. There is a sample chamber/sensor placed for optimum evaluation of ventilation with a numeric display of carbon dioxide.

Pulse Oximetry: The amount of oxygen on the hemoglobin molecule reflecting oxygenation.Normal value 93-100%.

IV. / EQUIPMENT

1. Personal protective equipment, including face shield, mask, and gloves

2. Capnograph

3. Airway adapter EtCO2:

For intubated patient with non-humidified ventilation, you can use a Microstream FilterLine set. For humidified ventilation, use a FilterLine H Set.

For non-intubated patients, the gas sample is taken through a Nasal FilterLine, or a Smart CapnoLine (which is a combined oral-nasal FilterLine). In parallel to the measurement of the CO2, oxygen (O2) may be delivered to the patient to support gas exchange. This is done by using an O2/CO2 FilterLine, or a Smart CapnoLine O2 (a combined oral-nasal O2/CO2 FilterLine).

IV. / PROCEDURE

The procedure serves as guidelines to assist personnel in accomplishing the goals of the procedure. While following these procedural guidelines, personnel are expected to exercise judgment within their scope of practice and/or job responsibilities.

Set-up

1. Obtain order for continuous end tidal carbon dioxide monitoring with capnography.

2. Verify correct patient with two identifiers.

3. If the patient is alert, explain the procedure to the patient; if the patient is not alert, explain the procedure to the family.

4. Ensure the patient understands pre-procedural teachings. Answer questions as they arise and reinforce information as needed.

5. Assess for proper functioning of capnograph, including electronic equipment, self-start, autocalibration, airway adaptor, sensor, and display monitor.

6. Connect capnograph into grounded wall outlet; connect appropriate patient cable into display monitor; turn on instrument.

7. Perform calibration routine. Calibration procedure should occur daily or more often when instrument is in clinical use.

8. If patient is not intubated, apply EtCO2 nasal cannula and connect to capnograph.

9. Assemble airway adaptor, sensor, and display monitor; connect to the patient’s circuit as close as possible to the patent’s ventilation connection.

10. Ensure that the light source is on top of the circuit so that condensation and secretions do not pool and obstruct the light transmission in mainstream sensor.

11. Set appropriate alarms. Alarm limits should include respiratory rate, apnea, default, high and low EtCO2 and minimal levels of inspiratory CO2.

Patient Monitoring and Care

1. Observe artificial airway for patency.

2. If the patient is not intubated, check nasal cannula or mouthpiece for proper placement and ensure that it is clear of secretions.

3. Observe waveform for quality and EtCO2value.

a. Observe waveform for gradually increasing EtCO2.

b. Observe for a gradual increase in both baseline CO2 and EtCO2

c. Observe for an exponential fall in EtCO2

d. Observe for decreased EtCO2 (with normal waveform)

e. Observe for a sudden decrease in EtCO2to low values

f. Observe for a sudden decrease in EtCO2to nearzero.

g. Observe for a sustained low EtCO2without alveolar plateau.

4. Routinely monitor the airway adaptor or sampling port for signs of obstruction

5. Evaluate the patient’s response to activities that may positively or negatively affect ventilation.

Using the FilterLine and Airway Adapter

1. Attach the female Luer connector to the CO2 inlet connector on the extension by pushing the socket cover down and screwing the connector into place.

2. Check that the FilterLine is not kinked.

3. Change the FilterLine if a “CO2 OCCLUSION” INOP appears on the monitor or if the readings become extremely erratic.

4. Disconnect the FilterLine during suctioning and nebulizing therapies.

5. Check the table in the Microstream CO2 Accessories section of the Accessories chapter for typical usage times for the different Microstream accessories.

6. CO2 values for non-intubated patients using Microstream accessories will always tend to be lower than for intubated patients. If values appear extremely low, check whether the patient is breathing through the mouth or whether one nostril is blocked

Removing Exhaust Gases from the System

WARNING Anesthetics: When using the Microstream CO2 measurement on patients who are receiving or have recently received anesthetics, connect the outlet to a scavenging system, or to the anesthesia machine/ ventilator, to avoid exposing medical staff to anesthetics.

Use an exhaust tube to remove the sample gas to a scavenging system. Attach it to the MMS Extension at the outlet connector.

Suppressing Zero Calibration

To prevent an automatic zero calibration from being started in the next five minutes,

  • In the setup CO2menu, select “No Zero for 5 Min”, or select the “Suppress CO2” Zero SmartKey, if configured.

Selecting “No Zero” for 5 Min or selecting the “Suppress CO2 Zero SmartKey” again before the timer has timed out resets the timer to five minutes, unless an AutoZero became due during the previous suppression.

Adjusting the CO2 Wave Scale

  1. In the CO2 wave menu or the setup CO2menu, select “Scale”.
  2. Choose a suitable scale range from the pop-up list.

Setting up CO2 Corrections

Temperature, water vapor in the patient’s breath, barometric pressure, and the proportions of O2, N2O and Helium in the mixture all influence CO2 absorption. If values seem inaccurately high or low, check that the monitor is using the appropriate corrections.

Correction
Altitude (M3014A only) / Altitude is set during installation. The monitor automatically applies an appropriate correction.
O2(M3014A only) / In the setup CO2menu, select Oxygen Corrand select a value between 0% and 100%, the default value is 16% (expired O2). If you are not measuring the expired O2, estimate it by subtracting 5% from the inspired O2.
Humidity / At installation, the monitor is configured to automatically apply either Body Temperature Pressure Saturated (BTPS) or Standard Temperature Pressure Dry (STPD). To see which, go to the setup CO2menu, and scroll down to look at HumidtyCorr.
N2O (M3016A mainstream and M3015A microstream only) / In the Setup CO2menu, select N2O Corrand turn on or off. If N2O is present in the ventilation gas mixture, you must turn this on.
If the N2O correction is not available in the setup CO2menu, the CO2 measurement in your MMS Extension does not require N2O correction or it is setup with Gas Corr(see below).
Gas (M3014A only) / In the setup CO2menu, select Gas Corrand select helium, N2O or turn off. If helium or N2O is present in the ventilation gas mixture, you must make the appropriate selection.
If the gas correction is not available in the setup CO2menu, the CO2 measurement in your MMS Extension does not require N2O or helium correction or the N2O correction is setup with N2O Corr(see above).
Correction
Agent (M3014A only) / In the setup CO2menu, select Agent Corrand select the concentration of the anesthetic agent (between 0.0% and 20.0%). If an anesthetic agent is present in the ventilation gas mixture, you must select the appropriate concentration.
Altitude (M3014A only) / Altitude is set during installation. The monitor automatically applies an appropriate correction.
O2 (M3014A only) / In the Setup CO2menu, select Oxy. Corr. and select a value between 0% and 100%, the default value is 16% (expired O2). If you are not measuring the expired O2, estimate it by subtracting 5% from the inspired O2.
Humidity / At installation, the monitor is configured to automatically apply either Body Temperature Pressure Saturated (BTPS) or Standard Temperature Pressure Dry (STPD). To see which, go to the Setup CO2menu, and scroll down to look at HUM Corr..
N2O (M3016A mainstream and M3015A microstream only) / In the Setup CO2menu, select N2O Corr. and turn on or off. If N2O is present in the ventilation gas mixture, you must turn this on.
If the N2O correction is not available in the setup CO2menu, the CO2measurement in your MMS Extension does not require N2O correction or it is setup with Gas Corr. (see below).
Gas (M3014A only) / In the Setup CO2menu, select Gas Corr. and select Helium, N2O or turn off. If helium or N2O is present in the ventilation gas mixture, you must make the appropriate selection.
If the Gas correction is not available in the setup CO2menu, the CO2 measurement in your MMS Extension does not require N2O or helium correction or the N2O correction is setup with N2O Corr. (see above).
Agent (M3014A only) / In the Setup CO2menu, select Agt. Corr. and select the concentration of the anesthetic agent (between 0.0% and 20.0%). If an anesthetic agent is present in the ventilation gas mixture, you must select the appropriate concentration.

Suppressing Sampling (not Mainstream CO2)

To temporarily stop sampling,

  • In the setup CO2menu, select Pump 15min off or use the CO2 Pump Off SmartKey if available.

Selecting Pump 15 min off again before fifteen minutes have passed resets the timer to fifteen minutes.

To re-start the pump

  • In the setup CO2menu, select Pump On.

Changing the Apnea Alarm Delay

This determines the time limit after which the monitor alarms if the patient stops breathing.

  1. In the Setup CO2menu, select awRR.
  2. In Setup awRR menu, select Apnea Time.
  3. Choose the apnea alarm delay time.

WARNING

Safety and effectiveness of the respiration measurement method in the detection of apnea, particularly the apnea of prematurity and apnea of infancy, has not been established.

Prolonged delay: The selected apnea alarm delay may be prolonged by up to 17 seconds, if an apnea occurs during the automatic zero process. This applies to the Microstream (M3015A) measurement only.

Deriving Alarms From awRR

  1. In the Setup CO2menu, select awRR.
  2. In the Setup awRR menu, select Alarms.
  3. Choose On to derive alarms from the airway respiration signal or Offto disable them.

Changing awRR Alarm Limits

  1. In the Setup CO2menu, select awRR.
  2. Select High Limit to set the upper alarm limit.

Select Low Limit to set the lower alarm limit.

  1. Select the appropriate setting.

V. / DOCUMENTATION

Documentation should include the following:

  • Patient and family education
  • Mechanical ventilator settings
  • Petco2 value and capnogram
  • Arterial blood gas values if ordered
  • Times of calibration
  • Respiratory therapies
  • Medications that may affect respiratory system (e.g. neuromuscular blockers, sedatives, or bronchodilators)
  • Unexpected outcomes
  • Nursing interventions

VI. / SUBMITTED BY

Lauren Walker RN, BSN, CCRN

Julia Burgess RN, MS, CCRN, CCNS

VII. / KEYWORDS

End-tidal, CO2, Nasal Cannula, Ventilation End tidal carbon dioxide, respiratory

VIII. /
EFFECTIVE DATE
/ July, 2012