Larsen & Toubro Star 55, Operating Manual

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Star 55
End tidal CO
2
is the concentration of CO
2
measured at the end of tidal volume
expired (Point D in above diagram).
A - B : The baseline i.e. the level of minimum CO
2
concentration,
observed immediately after inspiration.
B - C : The expiration phase of respiration cycle.
C - D : The expiratory plateau i.e. the period during which the level of
CO
2
in the lungs ceases to increase significantly.
D : The end-tidal concentration point i.e. the point at the end of
the expiration phase, at which EtCO
2
is measured.
D - E : The onset of the inspiration phase of the respiration cycle.
The production, transportation and elimination of CO
2
CO
2
is produced by all the cells in all the tissues in body as a by-product of
metabolism. From the cell, CO
2
diffuses into capillary blood, from where CO
2
is transported into venous circulation. During contraction of heart, venous blood
is pumped through pulmonary circulation to the lungs for gas exchange. Lungs
are made up of millions of alveoli, which permits easy gas diffusion
Figure 2.17
2.17