What does the Capnographic waveform represent?
Waveform capnography represents the amount of carbon dioxide (CO2) in exhaled air, which assesses ventilation. It consists of a number and a graph. The number is capnometry, which is the partial pressure of CO2 detected at the end of exhalation. This is end-tidal CO2 (ETCO2) which is normally 35-45 mm Hg.
What are the four phases of capnography?
This can be divided into several steps:
- Look for presence of exhaled CO2 (Is a waveform present?)
- Inspiratory baseline (Is there rebreathing?)
- Expiratory upstroke (What is the shape i.e. steep, sloping, or prolonged?)
- Expiratory/alveolar plateau (Is it sloping, steep, or prolonged?)
What happens to Capnogram waveform during inspiration?
During inspiration, CO2 is essentially zero and thus inspiration is displayed at the zero baseline. Phase 1 occurs as exhalation begins, which is shown as A to B on the capnogram. In phase 3 (C to D on the capnogram), all of the gas passing by the CO2 sensor is alveolar gas which causes the capnograph to flatten out.
What does a sloped upstroke on Capnogram indicate?
Prolongation or slanting of the expiratory upstroke phase II occurs when there is obstruction to expiratory gas flow (e.g., asthma, bronchospasm, obstructive pulmonary disease, and kinked endotracheal tube,1-9 or in the presence of leaks in the breathing system.
What causes curare cleft?
The “curare cleft” seen in the alveolar plateau is actually a patient making an attempt to breathe. With their feeble inspiratory effort, some fresh gas sucked from the ventilator tubing and past the capnometer, generating this pattern.
What characteristics are observed in a normal Capnogram?
A normal capnogram for patients of all ages is characterized by a set of specific elements: it includes 4 distinct phases (Figure 1), the CO2 concentration starts at zero and returns to zero (ie, there is no rebreathing of CO2), a maximum CO2 concentration is reached with each breath (ie, ETCO2), the amplitude depends …
What does a Capnograph measure?
Capnography is the measurement of exhaled CO2; the number is. displayed in millimeters of Mercury (mm Hg) or percent (%) CO2. Capnography provides the clinician with a waveform which tracks. exhaled CO2 over time.
What phase of the Capnogram reflects when the alveoli are full of inhaled oxygen and CO2 levels are very low?
Phase I (inspiratory baseline) reflects inspired gas, which is normally devoid of carbon dioxide. Phase II (expiratory upstroke) is the transition between VDana, which does not participate in gas exchange, and alveolar gas from the respiratory bronchioles and alveoli. Phase III is the alveolar plateau.
What is abnormal Capnogram?
A commonly seen abnormal capnogram results when the patient makes spontaneous respiratory efforts and inhales before the next mechanical inspiration. This characteristic cleft in the alveolar plateau is a useful clinical sign indicating that the patient has started to breathe (Figure 24-7).
What is a curare cleft?
When to use capnography?
Capnography is used to guide how quickly to ventilate a patient. In addition to this, capnography is used to correctly place a device in your airways. Capnography is used to evaluate ventilation. Ventilation refers to the movement of air out and in your lungs.
What is true of quantitative waveform capnography?
Quantitative Waveform Capnography. Quantitative waveform capnography is the continuous measurement of carbon dioxide (CO 2 ), specifically end-tidal CO 2. The capnography device uses a sensor that detects CO 2 levels in expired air. This device can be part of a nasal cannula filter line or be attached to a bag mask device or ET tube.
How is capnography measured?
Capnography measures exhaled breath by plotting the partial pressure of CO2 in wavelength form on an x and y axis grid. The capnograph displays wavelengths as well as numbered measurements – a normal reading falls between 30 and 40. The capnograph is the patient’s direct line of communication to his or her doctor…