End-Tidal CO2 (EtCO2)

The Wave Of The Future

EtCO2 Basics

EtCO2 measures ventilation

SAo2 measures oxygenation

Uses infra-red light to measure exhaled air

Vacuum in LP15 draws 50mL/min

EtCO2 Basics

Tachypnea - abnormally rapid breathing

Hyperventilation - Increased minute ventilation that results in decreased EtCO2 levels (hypocapnea)

Hypoventilation - Decreased minute ventilation that results in increased EtCO2 levels (hypercapnea)

Cellular Ventilation

Alveolar Ventilation

EtCO2 BasicsEtCO2 monitoring is continuous - changes are immediately seen (CO2 diffuses across membranes < 0.5 sec)

SAo2 monitoring relies on trending

EtCO2 Basics

Normal Values 35-45mmHg <35 = hyperventilation decreased metabolic state >45 = hypoventilation increased metabolic state

EtCO2 Basics< 35mmHg (Hyperventilation) Increased CO2 clearance (tachypnea) Decreased CO2 production (hypothermia, sedation, paralysis) Decreased delivery to lungs (decreased cardiac output) V/Q mismatch (ventilating non-perfused lungs - Pulmonary embolism)

EtCO2 Basics

> 45mmHg (Hypoventilation) Decreased central drive, muscle weakness, diffusion problems Increased CO2 production (Fever, burns, Hyperthyroidism, sz, Bicarb, ROSC, reperfusion)

EtCO2 Basics

Normal Capnogram

EtCO2 Basics

Baseline - CO2-free air in dead spaces

EtCO2 Basics

Expiratory Upstroke (exhalation)

EtCO2 Basics

Expiratory plateau (exhalation of mostly alveolar gases)

EtCO2 Basics

Inspiration (inhalation of CO2-free gases)

Bronchospasm

Normal Bronchospasm(Uneven alveolar emptying)

Emphysema

Pulmonary Edema

Poor Plateau

Differential Lung Emptying

Curare Cleft

Carbonated Beverages

Esophageal Intubation

Ineffective Respirations

Pain Management/Sedation

Hypothermia/Low Metabolic Demand

Malignant Hyperthermia

Metabolic StatesDiabetes/Dehydration EtCO2 tracks serum HCO3 & degree of acidosis ↓EtCO2 = metabolic acidosis

Metabolic States

Sepsis

EtCO2 inversely related to Lactate

The lower the EtCO2, the higher the lactate levels

Lactate levels >4 = sepsis

EtCO2 levels <25 = sepsis alert

Cardiac Output

Cardiac

CHF/Heart Failure

Cardiac Arrest