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Cardiac output - measures and derived indices

Created: 15/8/2005
 

Primary measured haemodynamic data

Arterial blood pressure (BP) systolic (SBP) = 90 - 140 mmHg
 
Diastolic (DBP) = 60 - 90 mmHg
 
Mean arterial pressure (MAP): [SBP + (2 x DBP)]/3 = 70 - 105 mmHg
 
Right atrial pressure (RAP) =  2 - 6 mmHg
 
Right ventricular pressure (RVP) systolic (RVSP) = 15 - 25 mmHg
 
Diastolic (RVDP) = 0 - 8 mmHg
 
Pulmonary artery pressure (PAP) systolic (PASP) = 15 - 25 mmHg

Diastolic (PADP) = 8 - 15 mmHg
 
Mean pulmonary artery pressure (MPAP): [PASP + (2 x PADP)]/3 = 10 - 20 mmHg
 
Pulmonary artery wedge Pressure (PAWP) = 6 - 12 mmHg
 
Left atrial pressure (LAP) =  6 - 12 mmHg 
 
Cardiac output (CO): HR x SV/1000 = 4.0 - 8.0 L/min 

Derived haemodynamic data

Cardiac index (CI): CO/BSA  = 2.5 - 4.0 L/min/m2
 
Stroke volume (SV): CO/HR x 1000 = 60 - 100 ml/beat 

Increased SV is associated with bradycardia and positive inotropic agents which increase contractility.
 
Stroke volume index (SVI): CI/HR x 1000 = 33 - 47 ml/m2/beat 
 
Systemic vascular resistance (SVR):  80 x (MAP - RAP)/CO = 1000 - 1500 dyne s/cm5 

SVR: Systemic vascular resistance. Represents the load applied to the left ventricular muscle during ejection.
 
Systemic vascular resistance index (SVRI):  80 x (MAP - RAP)/CI  = 1970 - 2390 dyne s/cm5/m2
 
Pulmonary vascular resistance (PVR): 80 x (MPAP - PAWP)/CO = <250 dyne s/cm5 

PVR is an index of the resistance offered by the pulmonary capillaries to the systolic effort of the right ventricle.

Pulmonary vascular resistance index (PVRI): 80 x (MPAP - PAWP)/CI = 255 - 285 dyne s/cm5/m2 
 
 

Haemodynamic parameters - adult

Parameter equations - Normal range

Left ventricular stroke work (LVSW): SV x (MAP - PAWP) x 0.0136 = 58 - 104 gm-m/beat
 
Left ventricular stroke work index (LVSWI): SVI x (MAP - PAWP) x 0.0136 = 50 - 62 gm-m/m2/beat
 
Right ventricular stroke work (RVSW): SV x (MPAP - RAP) x 0.0136 = 8 - 16 gm-m/beat
 
Right ventricular stroke work index (RVSWI): SVI x (MPAP - RAP) x 0.0136 = 5 - 10 gm-m/m2/beat 
 
Coronary artery perfusion pressure (CPP): Diastolic BP - PAWP = 60 - 80 mmHg
 
Right ventricular end-diastolic volume (RVEDV): SV/EF = 100 - 160 ml
 
Right ventricular end-systolic volume (RVESV): EDV - SV = 50 - 100 ml
 
Right ventricular ejection fraction (RVEF): SV/EDV = 40 - 60% 

Oxygenation parameters - adult

Parameter Equations - Normal range

Partial pressure of arterial oxygen (PaO2)  = 80 - 100 mmHg
 
Partial pressure of arterial CO2 (PaCO2)  = 35 - 45 mmHg
 
Bicarbonate (HCO3-)  = 22 - 28 mEg/L 
 
pH  7.38 - 7.42
 
Arterial oxygen saturation (SaO2)  = 95 - 100%
 
Mixed venous saturation (SvO2)  = 60 - 80%
 
Arterial oxygen content (CaO2):  (0.0138 x Hgb x SaO2) + (0.0031 x PaO2) = 17 - 20 ml/dl
 
Venous oxygen content (CvO2): (0.0138 x Hgb x SvO2) + (0.0031 x PvO2) = 12 - 15 ml/dl 
 
A-V oxygen content difference (C(a-v)O2): CaO2 - CvO2 = 4 - 6 ml/dl
 
Oxygen delivery (DO2): CaO2 x CO x 10  = 950 - 1150 ml/min
 
Oxygen delivery index (DO2I): CaO2 x CI x 10 = 500 - 600 ml/min/m2 
 
Oxygen consumption (VO2): (C(a - v)O2) x CO x 10 = 200 - 250 ml/min
 
Oxygen consumption index (VO2I): (C(a - v)O2 x CI x 10 = 120 - 160 ml/min/m2 
 
Oxygen extraction ratio (O2ER): [(CaO2 - CvO2)/CaO2] x 100 = 22 - 30%
 
Oxygen extraction index (O2EI): [SaO2- SvO2)/SaO2 x 100 = 20 - 25% 


ArticleDate:20050815
SiteSection: Article
 
   
    
                                            
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