# Formulas/Calculations for Vent settings Flashcards

1
Q

RAW

airway resistance

A

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)

2
Q

V (flow)

2 ways to calculate

A

V(flow)= (Vt(L) /Ti)x60
Or
Flow(V)= Ve x (I:E) ***add the I:E

3
Q

Spontaneous Ve (minute ventilation)

A

Total Ve-mechanical Ve

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

4
Q

Spontaneous Vt (tidal volume)

A

Spontaneous Ve (ml)\ Spontaneous Rate

5
Q

Spontaneous rate

A

Total rate - Set rate

6
Q

a/A ratio

A

Norm

>or equal to 70% *the higher the better

7
Q

A

Normal

8
Q

Pao2/Fi02

A

Normal

>or equal to 400

9
Q

CAO2

Total O2 content

A

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

10
Q

VO2

O2 Tissue consumption

A

Normal
3.5 to 5.0 vol %

Measures 02 consumption in the tissues.

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

11
Q

Ve (min. Ventilation)

A

Vt x RR

12
Q

Vt (tidal volume)

A

Ve/ RR

13
Q

A

1 ml per lb. of IBW (estimation)

14
Q

CV02

A

Normal
13-15vol %

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

Determines how well the tissues take up O2

15
Q

VA (alveolar Ventilation)

A

Normal
4-6 L/min

(Vt-VD) RR

Volume of inspired air that participates in gas exchange per minute

16
Q

VD/Vt

A

Normal
20 to 40%

> 60%= need for mechanical ventilation
Causes for increase: P.E,

(***PEC02 is from capon graphs)

PaC02 - PEC02/ PaC02 x 100

Relates to ventilation. Percentage of title volume that is unavailable for gas exchange

17
Q

CD (dynamic compliance)

A

Normal
30-40 cm h20 on vent
70-90 cm h20 off vent

Vt/ PIP-PEEP

Can decrease due to: secretions bronchospasm, biting tube, small or a endotracheal tube.

18
Q

CS (static compliance)

A

Normal
100 cm h20Off vent
40-60 cm h20on vent

Vt/ Pplat- PEEP

A decrease can be due to :pulmonary edema, pneumothorax,atelectasis, Pleural effusion, obesity, and ARDS.

19
Q

Spontaneous Ve
Spontaneous Vt
————————————
spontaneous Vt

A
1. Calculate mechanical ventilation
mechVe = mechRR x Vt (divide by 10000
to turn to L).
2. Calculate spontaneous Vt
sponVt = sponVe/ sponRR
—————————————————————-
3. SponVt =sponVe/sponRR
20
Q

ICP

A

Keep

21
Q

Ve for desired PaC02

A

Actual Ve x actual PaC02/ desired PaC02

22
Q

New Vt for desired PaC02

A

Current Vt x actual PaC02/desired PaC02

23
Q

Desired Fi02

A

Desired PaO2 x known FiO2/ known PaO2

24
Q

PA02 (Alveolar partial pressure of 02)

A

(Pb-47 cm h20)*Fi02 - (Pa02 x 1.25)

25
Q

IBW (ideal body weight)

A

M= 106+(6 x inches over 60in) /2.2

F= 105+(5 x inches over 60 in)/2.2