Exercise Testing (Mod10) Flashcards
In a healthy individual the ventilatory response to hypoxemia is increased with what?
In a healthy individual the ventilatory response to hypoxemia is increased with hypercapnia
- Healthy = increased VO2 Max
- Unhealthy = decreased VO2 max
What is VO2 max?
The maximum amount of oxygen that an individual can utilize during intense or maximal exercise.
- best indicator of cardiovascular fitness and aerobic endurance.
Best indicator of cardiovascular fitness and aerobic endurance?
VO2 max
Anaerobic threshold?
50-65% of body’s max O2 consumption
Metabolic cart?
- Inhaled O2 concentration
- Vt
- RR
- MV
Heart rate increases CO after what event?
HR increases CO after SV has reached max
- Decreased Vd/Vt during exercise is approximately 0.15-0.2
O2 carrying capacity with exercise?
O2 carrying capacity with exercise is 3x
What is monitored during Exercise testing?
Subject is monitored for:
HR, ECG
Minute Ventilation
CO2 production
Oxygen uptake
Saturations
Blood pressure (systolic & diastolic)
Blood gases, include lactate acid
What can increase the accuracy of exercise testing?
- Extra probe that can measure EtCO2 and EtO2, needs a tight mask for accuracy
- Blood gas to see how lungs compensate, expect CO2 low in the 20s and lactate to be high bc you force them to be in anaerobic metabolism. Have to state its at the end of exercise.
Purpose of cardiopulmonary exercise testing?
Assess if SOB is due to multiple organs or idiopathic and if its related to cardiac or pulmonary reasons
- If all the PFT come back normal then they would look for cardiac source and if its normal and then they do exercise test, and put them short of breath and see the source
- Tell how conditioned someone is, difference between normal ppl and athletes
What do we expect from exercise testing?
Oxygen consumption increases linearly with the work rate until the maximum O2 is reached. Thus O2 can be predicted from the work rate.
- VO2 is O2 consumption and linear with increase in work rate, as you work harder your consumption of O2 increases until you hit VO2 max, not matter how much O2 you breath in you can’t take anymore because you’re hit the max
- poorly conditioned hit the max earlier than those who do cardio
What does the VO2/Work graph compare?
- VO2 max/maximal oxygen uptake measures amount of oxygen that an individual can use during intense exercise of physical activity.
- Max rate at which body can consume O2 during exercise and reflect combined ability of lungs, heart, and skeletal muscles to deliver O2 to working muscles and use it for energy production
What should you aim for during exercise testing when keeping in mind VO2?
Try to get them at VO2 max within 9-10 max, how many watts we predict the patient to hit their max within 10 mins/
- 1-baseline,
- 2-pedaling with 0 resistance
- 3-climbing up a hill that’s getting gradually steeper
What happens when you hit anaerobic threshold?
Your heart rate and your mean arterial pressure will still go up, but your SaO2 is constant throughout
- Changes in heart rate, systemic bloocd pressure, and arterial o2 sats during exercise from rest to max exertion
As you approach anaerobic threshold, what happens to your heart?
HR climbs linearly for healthy people bc the work rate increases
- HR has to bring CO and deliver faster
- HR does plateau bc there is a max to your heart rate
- SATs remain constant, while MAP (BP) rises with HR.
- In healthy individuals lungs and heart are well enough that they are able to meet your O2 demands and your PO2 and saturations shouldn’t dip
What can be inferred if your PO2 and saturations dip with exercise testing?
Lung disease
What is R on the following plot for Anaerobic threshold?
respiratory quotient, it accelerates faster with exercise
What should you expect on the anaerobic threshold plot?
Normal Ventilation/Gas Exchange Responses During Exercise. Four variables as they might appear in a healthy young adult are plotted against o2. The dotted vertical line represents AT.
- E increases linearly with work rate at low and moderate workloads up to the AT, as does co2. At higher levels, E and co2 increase at a faster rate as HCO3− buffers lactic acid and as CO2 is produced.
- The ratio of co2 to o2 (RER) follows a similar pattern as RER approaches and then exceeds 1.
- VD/VT initially decreases rapidly as VT increases; it then continues to decrease but at a slower rate
How is EtCO2 affected when you hit the anaerobic threshold?
EtCO2 is stable as aerobic metabolism decreases (transition between compensation mechs)
- Your EtCO2 can decrease because your hyperventilating to remove CO2
What is ventilatory capaciy?
As the measured maximal voluntary ventilation (MVV)
- Calculated as FEV1x40
- Diff between Emax (exercise max) and ventilatory capacity is termed the ventilatory reserve or breathing reserve
- As you use more O2, ventilation rises in a linear fashion until anaerobic threshold
- constant rise whos body changes its way of metabolizing O2
Once you hit your anaerobic threshold; what happens to
- PaO2
- PaCO2
- pH
- HCO3
- Lactate
- Vd/Vt
The figure shows changes to AT
Indications for cardiopulmonary exercise test?
edit later
Bike vs treadmill for CPET?
Cycle is preferred bc you hit the VO2 max quicker and you have a shorter test
Absolute contraindications for CPET?
Absolute contraindications are serious ones that can hurt the patient if you stress them out
- Recent heart attack
- Chest pain
- History of passing out
- Active infections of the heart
- Heart failure not medicationed and not under control
- Room air destat <85%***, if they have low stats to start the test will not last long
Relative contraindications for CPET?
Relative, exercise testing is seeing if the condition is treated with the medications
Indications for exercise test termination?
- Chest pain might suggest ischemia
- Odd PVC is normal because you are pushing them but if yo have a lot then the heart is not liking it
- Systolic drops >20mmHg is uncommon because more likely it will rise but if it starts to drop >20 then stop
- If their stats drop and they are confused then stop
- If they want to stop you cant force them
