PressuresPressures

RARA : a = 2-6; V = 2-4 m = 3 (0-6): a = 2-6; V = 2-4 m = 3 (0-6)

RVRV :15-25 edp 0-5.:15-25 edp 0-5.

PAPA :15-25; diast. 6-10, m = 10-15.:15-25; diast. 6-10, m = 10-15.

PAWPAW : a = 6-12, V = 8-14, m 6-10 (12): a = 6-12, V = 8-14, m 6-10 (12)

LA (PV)LA (PV) : a=6-12, V=8-14, m = 6-10 (12): a=6-12, V=8-14, m = 6-10 (12)

LVLV : 90-120 / 0-10 (12): 90-120 / 0-10 (12)

SASA :90-120 / 60-75 (70-85).:90-120 / 60-75 (70-85).

PressuresPressures

i)i) RA a = RV edp RA a = RV edp

‘‘a’ a’ edp = TS edp = TS

ii)ii) PA diast. = LA m.PA diast. = LA m.

PA diast. PA diast. LA (m) = LA (m) = PVR PVR

iii)iii) PAW ‘a’ = LA ‘a’ = LV edp.PAW ‘a’ = LA ‘a’ = LV edp.

iv)iv) PAW ‘a’ (LA a) PAW ‘a’ (LA a) edp = obstr. edp = obstr.

(PV obstr, cortriat, MS, supra valv ring).(PV obstr, cortriat, MS, supra valv ring).

OxymetryOxymetry

Oxygen Capacity (vol. %)Oxygen Capacity (vol. %)

Oxygen content (vol. %)Oxygen content (vol. %)

Oxygen saturation (%)Oxygen saturation (%)

Vol % = ml O2 / 100 ml. Bl.Vol % = ml O2 / 100 ml. Bl.

Oxygen CapacityOxygen Capacity

1 gm Hb can carry 1.36 ml O2.1 gm Hb can carry 1.36 ml O2.

If Hb=15 gm : Capacity=15 x 1.36 =20.4If Hb=15 gm : Capacity=15 x 1.36 =20.4

If Hb=10 gm : Capacity=10 x 1.36 = 13.6If Hb=10 gm : Capacity=10 x 1.36 = 13.6

Hence Hb must be determined for the calculation of O2 Hence Hb must be determined for the calculation of O2 capacity.capacity.

Oxygen Saturation (%)Oxygen Saturation (%)

% of oxygenated Hb.% of oxygenated Hb.

Obtained directly using oxymeters.Obtained directly using oxymeters.

Pulm. Ven. Sat. = 98% (100%).Pulm. Ven. Sat. = 98% (100%).

Arterial O2 Sat. = PV sat = 98-100%.Arterial O2 Sat. = PV sat = 98-100%.

Mixed ven. O2 Sat = 75-80% (PA).Mixed ven. O2 Sat = 75-80% (PA).

A drop of 2% or A drop of 2% or in arterial O2 sat. compared to PV in arterial O2 sat. compared to PV Sat. = RSat. = RL shuntL shunt

Oxygen ContentOxygen Content

O2 content = O2 cap x O2 sat./100.O2 content = O2 cap x O2 sat./100.Hb 15 gm : Cap 15 x 1.36 = 20.4.Hb 15 gm : Cap 15 x 1.36 = 20.4.SA Sat. 98%; MV Sat. = 80%, 60%.SA Sat. 98%; MV Sat. = 80%, 60%.

SA Content = SA Content = 20.4 x 9820.4 x 98 = = 19.9919.99 100100

MV content = MV content = 20.4 x 8020.4 x 80 = = 16.3216.32 100100

MV content = MV content = 20.4 x 60 20.4 x 60 = = 12.2412.24 100100

Oxygen ContentOxygen Content

POPO2 2 – 100 – O– 100 – O22 contentcontent

(room air)(room air)HbHb BoundBound DissolvedDissolved1515 20.420.4 0.3 ml (1.5%)0.3 ml (1.5%)1010 13.613.6 0.3 ml (2.5%)0.3 ml (2.5%)

POPO2 2 – 600– 600

1515 20.420.4 1.8 ml (9%)1.8 ml (9%)1010 13.613.6 1.8 ml (14%)1.8 ml (14%)

Cardiac OutputCardiac Output

CO = CO = Oxygen consumption (VO2)Oxygen consumption (VO2) (PV) SA O2 Cont.–MVO2 cont. x 10(PV) SA O2 Cont.–MVO2 cont. x 10 Oxygen consumption can be measures but is Oxygen consumption can be measures but is

generally assumed depending on age, HR and BSA generally assumed depending on age, HR and BSA from nomograms.from nomograms.

O2 content needed to calculate flows.O2 content needed to calculate flows.

Cardiac OutputCardiac OutputO2 contentO2 content : (Hb 15) : (Hb 15)SA (98%)SA (98%) == 19.9919.991)1) MV (80%)MV (80%) == 16.3216.322)2) MV (60%)MV (60%) == 12.2412.24

CD (1) CD (1) == ________VO2______VO2______ == ______VO2___VO2___19.99 - 16.32 x 1019.99 - 16.32 x 10 3.67 x 10 3.67 x 10

CO (2)CO (2) == ____________VO2_____VO2_____ == ______VO2___VO2___19.99-12.24 x 1019.99-12.24 x 10 7.75 x 10 7.75 x 10

Cardiac OutputCardiac Output

i)i) COCO == ____VO2__VO2__ = = ____150___ 150___ = 4.08 l/m/M2 = 4.08 l/m/M2

3.67x 103.67x 10 3.67 x 103.67 x 10

ii)ii) CO = CO = ____VO2___VO2___ == ____150150___ = 1.93 l/m/M2___ = 1.93 l/m/M2

7.75 x 107.75 x 10 7.75 x 107.75 x 10

The lower the mixed venous O2 content (Or saturation) the The lower the mixed venous O2 content (Or saturation) the lower the cardiac output.lower the cardiac output.

Cardiac OutputCardiac Output

Qp)Qp) Pulm. Bl. flowPulm. Bl. flow == ____________________VO2___________VO2___________ PV O2 Cont.–PA O2 Cont. x 10PV O2 Cont.–PA O2 Cont. x 10

Qs)Qs) Syst. Bl. flowSyst. Bl. flow == ____________________VO2___________VO2___________ SA O2 cont.–MV O2 Cont. x 10SA O2 cont.–MV O2 Cont. x 10

In the absence of a left to right or right to left shunt Qp = QsIn the absence of a left to right or right to left shunt Qp = Qs

L L R shunts R shunts

Bl. Samples taken from PA, RV, RA, SVCBl. Samples taken from PA, RV, RA, SVC

ASDASD :: SVC to RASVC to RA

Sets 1-10%, 2-7%, 3-5%Sets 1-10%, 2-7%, 3-5%

VSDVSD :: RA to RVRA to RV

Set 1-7%, 2-5%Set 1-7%, 2-5%

PDAPDA :: RV to PARV to PA

1 set – 5%, 2-3%1 set – 5%, 2-3%

L L R shunts R shunts

(Qs) Syst. Flow(Qs) Syst. Flow == ____________________VO2___________VO2___________

SA O2 cont.–MV O2 Cont. x 10SA O2 cont.–MV O2 Cont. x 10

(Qp) Pulm. flow(Qp) Pulm. flow == ____________________VO2___________VO2___________

PVO2 Cont.–PA O2 Cont. x 10PVO2 Cont.–PA O2 Cont. x 10

QP – Qs = LQP – Qs = LR shunt.R shunt.

ShuntsShunts

QpQp == ____________VO2_______VO2_______ PVO2 – PAO2 x 10PVO2 – PAO2 x 10

QsQs == ____________VO2_______VO2_______ SAO2 - MVO2 x 10SAO2 - MVO2 x 10

L L R shunt = Qp – Qs R shunt = Qp – QsR R L shunt = Qs – Qp L shunt = Qs – Qp

Shunts (Bidirectional)Shunts (Bidirectional)

QpQp == ______VO2__________VO2__________ PVO2 – PAO2 x 10PVO2 – PAO2 x 10

QsQs == ______VO2__________VO2__________ SAO2 - MVO2 x 10SAO2 - MVO2 x 10

QepQep == ______VO2__________VO2__________ PVO2 – MVO2 x 10PVO2 – MVO2 x 10

L L R shunt = Qp – Qep R shunt = Qp – Qep

R R L shunt = Qs – Qep L shunt = Qs – Qep

Shunt RatioShunt Ratio

Qp / QsQp / Qs == __SAO2– MVO2___SAO2– MVO2_ PVO2 – PAO2PVO2 – PAO2

Ratio can be estimated if saturation and Ratio can be estimated if saturation and Hb are known.Hb are known.

Resistance to FlowResistance to Flow

Systemic vasc. resistance (SVR)Systemic vasc. resistance (SVR)Pulmonary vasc, resistant (PVR)Pulmonary vasc, resistant (PVR)Dynes / sec. / cmDynes / sec. / cm-5-5 or Wood unit. or Wood unit.

1 wood unit = 80 dynes / sec / cm1 wood unit = 80 dynes / sec / cm-5-5..

Always calculated as related to BSA.Always calculated as related to BSA. (Indexed)(Indexed)

Vasc. ResistanceVasc. Resistance

RR = = ______Delta P______Delta P______Q (l / m / MQ (l / m / M22))

SVRSVR == ____Ao (m) – RA (m)_Ao (m) – RA (m)_Qs (l / m / MQs (l / m / M22))

PVRPVR == ____PA m - LA m____PA m - LA m____QP (l / m / MQP (l / m / M22))

NormallyNormally PVR = 1 to 3 unitsPVR = 1 to 3 unitsSVR = 15-30 unitsSVR = 15-30 units