SpO2 – Pulse Ox Advantage: readings Disadvantage: Inaccurate with poor perfusion or artifact Terminate test if SpO2 is <%
Tidal Volume Vt = VE / RR Normal: ml per kg of body weight At low/moderate workloads total ventilation will increase by increasing At high workloads total ventilation increases by increasing
Frequency of Breathing (# of accumulated breathes) / testing time in minutes = RR Normal at rest: –
Minute Ventilation Vt x RR = Ve
Normal Resting: – L/min Normal Exercising: – L/min Maximum minute ventilation = FEV1 x Should be able to reach % of max If max minute ventilation is this indicates a primary ventilator limitation to exercise.
Alveolar Minute Ventilation = (Vt-) x or = VE – (VD x RR) Estimated anatomical deadspace is ml per lb of body weight
O2 Consumption – (VO2) Amount of O2 in L/min Normal at Rest: L/min Normal Exercising: Up to L/min Requires inline gas analyzers to measure O2%, an FeCO2 and a spirometer
O2 Pulse Volume of O2 consumer per (VO2/HR) x = mL O2/beat Normal Resting: – mL O2/beat Normal Exercising: – mL O2/beat Significance: O2 pulse that doesn’t increase with high HR indicates disease Tachycardia at rest will O2 pulse Arrhythmia will O2 pulse Beta Blockers will O2 pulse Plateau in O2 consumption will O2 pulse
CO2 Production (VCO2) – Amount of CO2 in L/min Normal resting: L/min Normal exercising: Up to l/min Gives indication of status FeCO2 x = VCO2
PH pH will decrease due to increased and acid In normal patients, pH will not decrease until is reached.
Alveolar-Arterial O2 Tension, A-a Gradient, PAO2-PaO2 or P(A-a)O2 PaO2 < means you should terminate the tes Normal P(A-a)O2 On RA: - On 100% O2: Less than Increase in P(A-a)O2 with in PaO2: Increased right to left , mismatch, defects Use Supplemental O2 if at rest.
Ventilatory Equivalent for O2 (Ve/VO2) Relationship of Ve to performed (VO2) Gives indication of of gas exchange at different workloads (BTPS)/(STPD) Normal at rest and low/moderate workloads: – L/LVO2 Increase in Ve out of proportion to in VO2 means disease Increase in Ve/VO2 at rest means
Ventilatory Equivalent for CO2 (Ve/VCO2) Relationship of Ve to (BTPS)/(STPD) Normal: - L/LCO2 Can be used to determine maximum tolerable workloads for patients with disease Anaerobic threshold reached when Ve/VCO2 is constant but Ve/VO2
PaCO2/ETCO2 Used to calculate Normal VD/Vt = - at rest with exercise Moderate Workloads: PaCO2 is constant, increases High Workloads: Metabolic due to lactic acid production
Respiratory Exchange Ratio (RER) Relationship of O2 consumption and CO2 production at the mouth which represents gas exchange in the lungs RER = / or (FeCO2xVe)/VO2 Normal at rest: Normal with Exercise: or greater RER should at anaerobic threshold
Hemodynamics Cardiac Monitor – Simplest way to monitor heart rate and rhythm. Normal HR: –
Blood Pressure: Equipment: Indwelling catheter and pressure transducer You can also take BP Normal Values: Systolic: Diastolic: Mean: MAP = (2x + )/3 Heart spends twice as much time in .
Central Venous Pressure (CVP) Used to Monitor systemic drainage and function of the heart. Catheter is located in . Normal: - mmHG or - cmH2O CVP – AKA: Right Pressure R Atriral filling pressue side preload Right ventricular pressure ventricular end pressure
Pulmonary Artery pressure (PAP) PAP and PCWP are measure with tipped directed pulmonary artery catheter (Swan Ganz) Catheter is directed through the side of the heart and positioned in Normal PAP: Systolic: mmHg Diastolic: mmHg Mean: mmHg Mixed samples should be drawn from pulmonary artery. If blood is bright red the balloon was or wedged if PaCO2 = PaO2
Pulmonary Capillary Wedge Pressure (PCWP) When balloon is it will measure PCWP Normal = mmHg (4-12) Estimates pulmonary drainage back to heart PCWP aka: atrial pressure Left atrial pressure Left side preload ventricular filling pressure Left end diastolic pressure
Cardiac Output (Qt) Output of left to systemic circulation Normal Qt is L/min (4-8) depending on body size Fick equation: Qt = /(C(a-v)O2x ) If stroke volume is known: Qt= x Thermal Dilution: Cold saline injection Cardiac Index = /() Normal: – lpm/m2
CVP: ↑ ↑ PAP: N ↓ PCWP: N ↓ QT: N = Heart Failure, Pulmonale, Valve Stenosis
CVP: ↑ PAP: ↑↑ PCWP: N ↓ QT: N = Disorders, Pulm , HTN, Air
CVP: N PAP: ↑ PCWP: ↑↑ QT:↓ = heart Failure, valve stenosis, , High effects
CVP: ↑↑ PAP: ↑ PCWP: ↑ QT: ↑ = CVP: ↓↓ PAP: ↓ PCWP: ↓ QT: ↓ =
Systemic Vascular resistance (SVR) : Pressure gradient across circulation divided by SVR = ( – ) / Qt Normal: < mmHg/l/min or 1600 Dynes/sec SVR is with systemic hypertension or vasoconstriction
Pulmonary Vascular Resistance (PVR): Pressure gradient across circulation divided by Qt PVR = ( – ) / Qt Normal: < mmHg/L/mi or 200 Dynes/sec PVR is increased with , HTN, disease
Metabolic Measurements -by-breath measurement Determines measurements of VO2, VCO2, RR, Vt Requires use of one way valve, and continuous sampling of gases.
Mixing Chamber Pt inspires room air via 1 way valve then exhales into gas mixing chamber with to completely mix the gases and concentration are measured.
