# Formulas/Calculations for Vent settings Flashcards

RAW

airway resistance

Normal

.6 to 2.4

PIP-Pplat/V(flow) (l/sec) ***divide flow by 60 1st.

Increases due to airway narrowing in intubated patient.

***caused by secretions (suction) to improve RAW), Obstructions, or bronchospasm (give bronchodilators to improve)

V (flow)

**2 ways to calculate**

V(flow)= (Vt(L) /Ti)x60

Or

Flow(V)= Ve x (I:E) ***add the I:E

Spontaneous Ve (minute ventilation)

Total Ve-mechanical Ve

**total Ve is what’s set and what pt is doing

Spontaneous Vt (tidal volume)

Spontaneous Ve (ml)\ Spontaneous Rate

Spontaneous rate

Total rate - Set rate

a/A ratio

Norm

>or equal to 70% *the higher the better

A–a gradient

Normal

Pao2/Fi02

Normal

>or equal to 400

CAO2

Total O2 content

Normal

17-20 %vol

(Hgb x 1.36 x SaO2) + (Pa02 x .0031)

Total amount of 02 carried in 100 ml of blood can be reduced due to

VO2

O2 Tissue consumption

Normal

3.5 to 5.0 vol %

Measures 02 consumption in the tissues.

5% = infection/sepsis or decreased C.O.

Ve (min. Ventilation)

Vt x RR

Vt (tidal volume)

Ve/ RR

VD ( dead space)

1 ml per lb. of IBW (estimation)

CV02

Normal

13-15vol %

(Hgb x 1.36 x SvO2) + (PvO2 x .003)

Determines how well the tissues take up O2

VA (alveolar Ventilation)

Normal

4-6 L/min

(Vt-VD) RR

Volume of inspired air that participates in gas exchange per minute