Background and Clinical Pearls
Unrecognized misplaced intubations are preventable tragedies that should never occur, yet reported rates in EMS range from 7%-25%. The square wave of the capnograph is real-time proof that the lungs are being ventilated and can virtually eliminate this catastrophic error. Other approaches, such as colorimetric EtCO2 detectors, esophageal detection devices, and auscultation, do not replace continuous capnography which is the standard of care for several years. Colorimetric EtCO2 sensors are poorly sensitive during hypoperfusion with low EtCO2; they do not provide a numeric CO2 level, can be positive despite esophageal or hypopharyngeal tube placement, and lose their color change shortly after placement, so they do not provide continuous confirmation.
Aside from ET tube placement, capnography offers additional information about ventilation and perfusion that can improve care for respiratory, cardiac, brain injury, and shock patients. Reasons for hypocapnia include hyperventilation, hypoperfusion (CO2 does not return to the lungs), hypothermia (CO2 is a byproduct of metabolism and metabolism is slowed), and metabolic acidosis (e.g., DKA and sepsis; CO2 is lost as bicarbonate, which is buffering the acidosis). Capnography prevents hyperventilation and associated harm (cerebral vasoconstriction, decreased cardiac output, the inability of oxygen to dissociate from hemoglobin, and vomiting) from bagging with excessive rate or volume. Reasons for hypercapnia include ventilatory failure (e.g., asthma exacerbation), chronic CO2 retention (e.g., COPD), and respiratory acidosis.
Other clinical applications of capnography include titrating naloxone, monitoring the effectiveness of CPR, identifying ROSC without pausing compressions, termination of resuscitation, and recognizing severe sepsis/septic shock (EtCO2 less than 25 correlates with a lactic acid greater than 4), identifying bronchoconstriction, and assessing whether interventions are working or whether the patient is deteriorating.
Performance Improvement and Best Practices
Set up the capnography while preparing for intubation. For initial confirmation, the capnography can and should be used instead of the less reliable colorimetric device. Look for “squares” on the capnography display. Use capnography inline between the mask and bag (with continuous mask seal) for breath-to-breath confirmation of adequate ventilation and to avoid hyperventilating.
Patient Safety Clinical Check List
Assure Waveform Capnography – Invasive (EtCO2) on all patients intubated or with advanced airway
Use Waveform Capnography – Non-Invasive (EtCO2) on patients meeting local protocol including diabetes, seizure, metabolic, ALOC, respiratory, cardiovascular, or other acute illnesses or injuries that could benefit from capnography.
Other Relevant Data and Educational Resources
https://www.ems1.com/capnography/articles/5-things-to-know-about-capnography-in-cardiac-arrest-YipMTGQ2yTt5mTub/#:~:text=A%20higher%20ETCO2%20reading%20during,the%20chances%20of%20survival%20are.
Rural EMS Counts Patient Safety Measure
Safety- ETCO2 Monitoring with Advanced Airway
Description: This report calculates how often at least one ETCO2 measurement was recorded when an advanced airway was used.
This report identifies the patient population:
· Treatments Performed (per Patient): Combitube, EasyTube Airway, iGEL, King Airway, Nasotracheal Intubation, Needle Cricothyroidotomy, Orotracheal Intubation, Pertrach, QuickTrach (Adult), QuickTrach (Child), Rapid Sequence Intubation (RSI), Retrograde Intubation, Sedation Assist Intubation (SAI), Surgical Cricothyroidotomy, Video Laryngoscopy
· First Successful Advanced Airway Attempt Number: 1, 2