Airway - Capnography and Capnometry

Question 1

Monitoring that provides a waveform capable of examining expired CO2 over time.

A. capnography
B. capnometry

Answer 1

A. capnography

Question 2

In the US, asthma exacerbation accounts for approximately ______ ED visits annually.

Answer 2

2 million

Question 3

Reliance of auscultation cannot be relied upon, as there is poor ______ reproducability.

Answer 3

interobserver (between providers)

Question 4

Capnometry shows only a(n) ______.

Answer 4

exhaled carbon dioxide partial pressure (PaCO2)

Question 5

Between the E2 (mixed air expiration) and E3 (expiration of alveolar air) exists the ______.

Answer 5

alpha angle

Question 6

The alpha angle measures approximately ______ in healthy individuals.

Answer 6

110*

Question 7

The alpha angle on capnography increases with ______.

A. Bronchodilation
B. Bronchoconstriction

Answer 7

B. bronchoconstriction

Question 8

Explain the changes to the capnograph in normal airways.

Answer 8

The alpha angle is measured between the E2 (mixed air expiration) and E3 (expiration of alveolar air) segments of the capnograph.

E2 indicates mixed air, or a combination of dead space air and the beginnings of alveolar air. As alveolar air (containing CO2) is exhaled, the capnograph rises sharply.

E3 is solely alveolar air. As such, there should be a [CO2] during exhalation, causing a “plateau” on the capnograph.

Question 9

Explain why the alpha angle in capnography increases with bronchoconstriction.

Answer 9

Slow exhalation of both mixed air (E2) and alveolar air (E3) secondary to bronchoconstriction results in an decreased “slope”/increased alpha-angle on the capnograph.

This results in the “shark-fin” pattern.