Exercise testing

Indications for Exercise Testing Chief complaint of [blank_start]dyspnea[blank_end] on exertion To determine ventilator [blank_start]limitations[blank_end] to work To determine [blank_start]cardiac[blank_end] limitations to work To determine [blank_start]maximum[blank_end] workloads for developing or adjusting exercise plan or [blank_start]activities[blank_end] [blank_start]Disability[blank_end] Purposes

Contraindications PaO2 < [blank_start]45[blank_end] on RA PaCO2 > [blank_start]70[blank_end] FEV1 <[blank_start]30[blank_end]% Recent [blank_start]MI[blank_end] Unstable [blank_start]angina[blank_end] 2nd or 3rd degree [blank_start]heart[blank_end] block [blank_start]Rapid[blank_end] ventricular or atrial [blank_start]arrhythmia[blank_end] Orthopedic problems that impairs activity Severe Aortic [blank_start]Stenosis[blank_end] CHF [blank_start]Uncontrolled[blank_end] HTN Neurological Disorders Dissecting [blank_start]Aneurysm[blank_end] Severe Pulmonary [blank_start]Hypertension[blank_end]

Normal response to stress Test Heart rate will [blank_start]increase[blank_end] linearly with increased workload Increased heart rate without ECG changes indicates [blank_start]deconditioning[blank_end] ST depressions >[blank_start]1[blank_end] mm for [blank_start].8[blank_end] seconds indicates ischemia PVCs with exercise are associated with ischemia if >[blank_start]10[blank_end] per [blank_start]minute[blank_end] If systolic blood pressure [blank_start]doesn’t[blank_end] rise, cardiac output is not [blank_start]increasing[blank_end] Respiratory rate, tidal volume and minute volume will [blank_start]increase[blank_end] during testing VCO2 and VO2 will rise together to keep RER near [blank_start].8[blank_end] pH will initially [blank_start]increase[blank_end] but will [blank_start]decrease[blank_end] at anaerobic threshold VD/VT will [blank_start]decrease[blank_end] because of increased [blank_start]perfusion[blank_end] Pulmonary Artery pressure will remain [blank_start]constant[blank_end] in normal patients.

Limitations to Exercise testing Ventilatory Limitations @ low/mod workload: Maximum minute ventilation = FEV1 x [blank_start]35[blank_end] Ve/VO2 >[blank_start]30[blank_end] L/LO2 Respiratory [blank_start]Acidosis[blank_end] Increased [blank_start]RER[blank_end] Decrease in O2 Sat [blank_start]Increased[blank_end] PAP Normal [blank_start]ECG[blank_end] and HR

Limitations to Exercise testing Cardiac Limitation @ low/mod workload: Significant [blank_start]ECG[blank_end] Changes Diastolic Pressure [blank_start]falls[blank_end] Systolic Pressure does not [blank_start]rise[blank_end] O2 pulse [blank_start]decreases[blank_end] Vt, RR, Ve is less than [blank_start]70[blank_end]% of MMV

Limitations to Exercise testing Poor Conditioning Present with [blank_start]increased[blank_end] HR and low/mod workloads with normal ECG and Vt, RR, Ve <[blank_start]70[blank_end]% MMV Poor Effort Present when ECG, SaO2 and HR are [blank_start]normal[blank_end] and anaerobic threshold is [blank_start]not[blank_end] achieved and Ve <[blank_start]70[blank_end]% MMV

Workload: Amount of [blank_start]energy[blank_end] being generated by patient during exercise. Measure in kilopond meters (kpm) Power: Amount of [blank_start]work[blank_end] per minute. Measure in [blank_start]watts[blank_end]. 1 watt = 6.12 kpm/min Metabolic Equivalents (METS) – Unit that measures O2 [blank_start]consumption[blank_end] per kg of body weight. 1 met = 3.5 mL/O2/kg (normal at rest) VO2 is measured during test and [blank_start]divided[blank_end] by pt weight in kg, then divided by 3.5 to get METS. Anaerobic Threshold – Level of exercise or VO2 at which [blank_start]anaerobic[blank_end] metabolism will begin to supplement aerobic metabolism. Lactic acid increases, pH decreases, HR is stable, Ventilatory equivalent for O2 and CO2 changes. O2 Max – [blank_start]Work[blank_end] continues to increase but [blank_start]VO2[blank_end] does not.

Steady State Vs Multistage Testing Steady State – Pt is exercised at [blank_start]submaximal[blank_end] level for 5-8 minutes at 50-[blank_start]75[blank_end]% of max load. (220-age = max HR) Once that target is reached, timing begins, measurements are made during final [blank_start]1[blank_end]-[blank_start]2[blank_end] minutes. Multistage – Workloads are [blank_start]increased[blank_end] and measurement made at the end of each [blank_start]stage[blank_end] (increase at 15 watts/min) <50 watts – [blank_start]low[blank_end] 50-100 watts – [blank_start]medium[blank_end] >100 watts – [blank_start]high[blank_end] 200 watts [blank_start]too[blank_end] high for stress testing. Can be changed every [blank_start]1[blank_end]-[blank_start]6[blank_end] minutes by increasing [blank_start]speed[blank_end], grade, or [blank_start]resistance[blank_end]. To verify treadmill is at a 10% incline – take a [blank_start]30[blank_end]” carpenter’s level and place on treadmill. The High end should be [blank_start]3[blank_end]” above the low end. 3” Rise / 30” run = 10 Set workload at [blank_start]10[blank_end] – [blank_start]15[blank_end] watts/min to reach 100 -150 watts in 10 min.

Stress Test without Gas Analysis (Multistage) Prepare Patient: 12 lead [blank_start]ECG[blank_end] – resting. Hx and physical exam. Informed consent Equipment: Treadmill, cycle or step Pt is stressed until [blank_start]Max[blank_end] HR achieved or pt develops [blank_start]symptoms[blank_end] that indicate to stop. Workload should gradually be [blank_start]decreased[blank_end] and pt monitored until vitals return to [blank_start]normal[blank_end] Stress testing with Gas Analysis (Steady State) Pt is prepared and stressed at [blank_start]sub[blank_end] maximal level for 5-8 minutes Expired gas is collected near [blank_start]end[blank_end] of each stage and during final [blank_start]1[blank_end] – [blank_start]2[blank_end] minutes of testing Collected using: Volume Spirometer, pneumotach, or breath by breath analysis. Measurement Includes: Exhaled [blank_start]Volume[blank_end], Temperature, Time of collection, respiratory [blank_start]rate[blank_end], [blank_start]Fe[blank_end]O2, [blank_start]Fe[blank_end]CO2 Allows for calculation of: [blank_start]Minute[blank_end] ventilation, Vt, [blank_start]VO2[blank_end], CO2 Production, Respiratory Exchange [blank_start]Ratio[blank_end], VE/VO2, VE/VCO2

Stress Testing with Gas Analysis and ABG ABG is performed [blank_start]same[blank_end] time as gas analysis Inability to stabilize arm for [blank_start]puncture[blank_end] is a problem. Arterial line would be [blank_start]preferred[blank_end] Indicated for patients with primary [blank_start]pulmonary[blank_end] problems Additional measurements: Physiologic [blank_start]Deadspace[blank_end], [blank_start]VA[blank_end], VD/Vt, [blank_start]Cardiac[blank_end] Output

Bruce Protocol: Workload is increased every [blank_start]3[blank_end] minutes. Borg Scale: Scale of 1 – [blank_start]20[blank_end]. Modified Borg Scale: 1 – [blank_start]10[blank_end]

Specific Reasons for ending exercise test [blank_start]2[blank_end]mm elevation in [blank_start]ST[blank_end] segment Inverted [blank_start]T[blank_end] waves Presence of large [blank_start]Q[blank_end] waves Vtach or [blank_start]SVT[blank_end] Multifocal [blank_start]PVC[blank_end] 2nd or 3rd degree heart block [blank_start]changes[blank_end] Exercise induced right or left bundle branch block [blank_start]Angina[blank_end] that progresses with testing Sweating and pallor Systolic pressure >[blank_start]250[blank_end] or diastolic >[blank_start]100[blank_end] Systolic Pressure does not [blank_start]increase[blank_end] or falls[blank_start]10[blank_end] as workload increases Lightheadedness Cyanosis Nausea Muscle [blank_start]Cramps[blank_end] Hyperventilation

Tidal Volume Loops Plotted on top of [blank_start]FVC[blank_end] loop [blank_start]IC[blank_end] during exercise is used to position the loop on top of [blank_start]resting[blank_end] loop Normal response to exercise will demonstrate a decrease in [blank_start]IRV[blank_end] and [blank_start]ERV[blank_end] in order to increase Vt and Ve

Pt with Hypoxemia Monitor titration with pulse ox If resting SpO2 is low do O2 titration at [blank_start]rest[blank_end] before exercise titration

6 Minute Walk test Pt is to walk as far as possible in [blank_start]6[blank_end] minutes Pt can slow down or rest if needed. Record Symptoms and SpO2 during [blank_start]rest[blank_end] stop Terminate test if significant [blank_start]angina[blank_end], mental confusion or SpO2 <[blank_start]85[blank_end]%

Safety Do a HX for [blank_start]contraindications[blank_end], Physical [blank_start]Exam[blank_end], [blank_start]ECG[blank_end] and [blank_start]ABG[blank_end]