What is contraindicated for a patient who is on pulse oximetry monitoring?

Before performing an exercise test, the health professional should evaluate whether the patient should participate in exercise training based on:

1. A review of the patient’s medical history.
2. An evaluation of the patient in relation to the contraindications and precautions identified below.

All patients should be evaluated for contraindications and precautions to exercise.

Supervisory staff should be aware of the criteria for termination of a test, and other important safety issues.

For patients with lung cancer and bony metastases best practice recommendations are available. The presence of bony metastases should not preclude exercise prescription, however people at higher risk of exercise-related bony complications should be identified.

Exercise Recommendation for People With Bone Metastases

*Note: Stable exertional angina is not an absolute contraindication to exercise, but the test should be performed after administration of anti-angina medication and with rescue nitrate available.

* Depending on the experience of the supervising staff and on the patient’s clinical presentation, the test may continue even if SpO2 < 80%. If the test is stopped, recommence testing when the patient feels able. Alternatively, consider repeating the test with supplemental oxygen. See testing protocol for oxygen supplementation.

* In PAH , patients with R to L Shunt/ Eisenmenger’s Syndrome low oxygen levels are normal and not a contraindication for undertaking a walk test. If on LTOT then use oxygen during the test.

Safety Issues Associated With Exercise Testing

• The health professionals supervising the exercise program will need to be trained in cardiopulmonary resuscitation.
• Local area safety procedures should be established during program set-up.
• Where possible, “crash trolleys” and oxygen should be in the vicinity of the area designated for exercise.
• Programs that are not run in a hospital environment (e.g. community programs) should ensure adequate emergency procedures are in place, including a telephone to call an ambulance.
• If the patient is on long-term oxygen therapy, the exercise tests should be carried out using the prescribed level of inspired oxygen.

Safety Monitoring During Walking Tests

During walking tests, the health professional should ensure that:

• Pulse oximetry is used to measure heart rate and oxygen saturation (i.e. the patient’s physiological response to exercise).
• The breathless (Borg) score is used to measure the patient’s perception of dyspnoea during exercise.

Perfusion at the site of monitoring

• Blood pressure generally needs to be >80 SBP
• Vascular impingement from any cause
• AV fistula can decrease distal flow
• Elevation with respect to the heart
• Compression by the probe
• Cardiac arrest (don't use during arrest)
• Heart Rate extremes <30 or >200
• Cold
• Fear (Endogenous catecholamines)
• Medications

Technique

• Applied to the best site ie. index finger (thumb ok in kids)
• Sensor attachment flush with tissue surface
• Local vasodilator such as methyl salicylate 10-30% and menthol 2-10% can be used if long transport
• Don't forget to remove or deflate BP cuff or band
• SpO2 Heart Rate MUST match actual pulse rate!!!!!
• Waveform or LED Color needs to confirm clean sample
• Take all readings when the probe is at heart level

Dyshemoglobinemia (Dysfunctional hemoglobin)

• Carboxyhemoglobin readings unreliable
• Methemoglobinemia " "
• Sickle Cell Anemia " "
• Thalassemias " "
• Anemias " "

Interference - readings unreliable

• Electronic/Electrical - RF, High tension lines rarely
• Movement - patient, sensor, stretcher, vehicle, active seizure
• Radiated light - infrared, visible and ultraviolet
• Nail polish, heavy, or dark
• Artificial Fingernails
• Dark pigmentation (not too much of a problem with finger robe)
• Intravenous Dyes such as Cardiogreen (within 48 hrs)
• Pulsatile venous system ie. CPR or tricuspid regurgitation

Normal Values (at sea level)

• Healthy patient on room air 94-100%
• COPDer on room air 90-100%
• 92% Sat is roughly equal to a Pa02 of 80 mm Hg, the threshold of hypoxia. (these values are relative and can change based on shifts of the Oxyhemoglobin Dissociation Curve or your elevation above or below sea level)

Caveats

• Use as tool to worry you, not to make you feel better
• Don't triage with a pulse oximeter
• Don't deny a SOB patient O2 while waiting for an SpO2
• Don't forget to document all readings and changes on the PCR. 

Examples:

• 10:42 SpO2 = 97% on 100% oxygen.
• 23:00 SpO2 = 98% on room air.

Is there a contraindication for pulse oximetry?

What are the nursing considerations when using pulse oximetry on a patient?

Which may cause false low readings in pulse oximetry?

What are the risks associated with pulse oximeters?