Calculations

Question 1

Estimating heart rate from an ECG tracing

Answer 1

300# of lage boxes b/n R wave

1500/# of small boxes b/n R

Question 2

Pulse pressure

Answer 2

Systolic pressure -diastolic pressure

Question 3

MAP

Answer 3

MAP =(2x diastolic)+systolic/3

Question 4

Cardiac output(duck equation)

Answer 4

Qt=vo2/C(a-v)o2(10)

Question 5

Cardiac output(stroke volume equation )

Answer 5

qt =heart rate x stroke volume

Question 6

Stroke volume

Answer 6

Qt/heart rate

Question 7

Cerebral perfusion pressure (CPP)

Answer 7

CPP=MAP-ICP

Question 8

Cardiac index

Answer 8

CI=qt/BSA= cardiac output/body surface area

Question 9

Systemic vascular resistance (SVR)

Answer 9

MAP-CVP/Cardiac output

To convert to dynes,multiply mmgh/l/min by 80

Question 10

Pulmonary vascular resistance (PVR)

Answer 10

(MPAP-PWP)/cardiac output

Question 11

PAO2

Answer 11

(Pb-ph2o)x FIO2-PaCO2/0.8

Paco2 X1.25

Question 12

A-aDo2

Answer 12

PAO2-Pao2

Question 13

Pao2/FIO2 ratio or P/f ratio

Answer 13

Pao2 \ FIO2

Question 14

Ca02

Answer 14

(Hbx1.34xSa02)+(Pa02x.003)

Question 15

Cv02

Answer 15

(Hb x 1.34 x SvO2) + (Pv02 x 0.003)

Question 16

C(a-v)O2

Answer 16

Cao2-CVO2

Question 17

Q_t

Answer 17

VO2/C(a-v)O2 *10

Question 18

VO2

Answer 18

QtC(a-v)O210

Question 19

Qs/Qt

Answer 19

(A-aDO2).003/ (A-aD2).003 +C(a-v)O2

Question 20

SaO2

Answer 20

Pao2 +30(when Pa02 is b/n 40 and 60 torr

Question 21

Oxygen index(OI)

Answer 21

Paw x FIO2/PaO2 x100

Question 22

Vd/vt

Answer 22

Paco2-PEco2/Paco2 * 100

Question 23

Desired minute volume

Answer 23

(VEPaCo2)=(VEPaCO2)

Question 24

Suction catheter size

Answer 24

Catheter size =ID size/2 *3u

Question 25

To approximate FIO2 with a nasal cannula

Answer 25

For every 1 L/min.increase in flow rate FIO2 increase by 4%

20 +(4*L)= approximate FI02

Question 26

Ideal body weight

Answer 26

50kg+(2*inches over 5ft
+ 2 m
-2 f

Question 27

Exhaled Tidal volume (VT)

Answer 27

(Ve\f)

Question 28

VE

Answer 28

Vt*f

Question 29

Alveolar minute ventilation (vA)

Answer 29

(Vt-vd)*f

Use the approximation of ml per Lb. of ideal body weight for vd

Question 30

Dynamic compliance

Answer 30

Exhaled volume/(peak inspiration pressure -peep)

Question 31

Static compliance

Answer 31

Exhaled volume/plateau pressure -peep

Question 32

Airway resistance(Raw)-estimate

Answer 32

Raw peak pressure-plateau pressure

Question 33

Work of breathing

Answer 33

P x v or change in pressure x change in volume

Question 34

Rapid shallow breathing index (RSBI)

Answer 34

Respiratory Rate \vt(L)

Question 35

He/02

Mixture using an oxygen flowmeter

Answer 35

Actual flow= indicate flow * factor

Question 36

He/O2 factors:

Answer 36

80/20 mixture:1:8

70/30 mixture 1.6

Question 37

Volume lost through chest tubes

Answer 37

Deliver tidal volume-exhaled tidal volume=lost volume

Question 38

Patient’s maximum heart rate:(220-age in years)

Answer 38

Patient’s maximum heart rate:(220-age in years)