E2 Pulse Oximeter

This equipment is mainly important for breathing problems as in Breathing problems of a neonate and young infants.

Subsection of this chapter:

1. Clinical Problem
2. Assessment
3. Management
4. Infection Prevention
5. Complications
6. Care & Maintenance
7. Troubleshooting & Repair

NEST360°. Newborn Essential Solutions and Technologies-Education – Clinical Modules: Pulse Oximeter. (June 2020). License: CC BY-NC-SA 4.0.

Clinical Problem

Assessment of oxygen saturation with a pulse oximeter should be used as part of routine assessment for all infants on admission.

Pulse oximeters should also be used during treatment for all sick or at-risk patients, or those being treated with oxygen therapy (1.1a, 1.1b), CPAP (1.2), or any form of assisted ventilation.(1.3)

Assessment

Peripheral pulse oximetry is a non-invasive & painless process of measuring heart rate and oxygen saturation (oxygen bound to haemoglobin in the capillaries).

Pulse oximeters may be used to help determine the severity of an infant’s illness by evaluating if blood oxygen saturation is low and if respiratory support is needed. Pulse oximeters also may be used to assess the success of treatment and determine a need for increasing or decreasing respiratory interventions to achieve target SpO2.

Pulse oximeters have one red- and one infra-red light-emitting diode and a photodetector. (2.1) The light emitted by the diodes is absorbed by tissues, and amount of absorption is measured by the photodetector. Functional haemoglobin bound with oxygen is called oxyhaemoglobin. Percent saturation of oxygen bound to haemoglobin is called SpO₂. A microprocessor within the pulse oximeter determines the percent of oxygen in the blood by comparing the concentration of deoxyhaemoglobin to oxyhaemoglobin at two different light wavelengths. (2.2)

When using a pulse oximeter, several factors impact the stability of the patient’s trace. Examples of a “normal signal” & potential “poor traces” are below. (2.3)

Pulse oximeters may be:

• Fixed (2.4) (for continuous reading of one patient)
• Handheld (2.5) (for spot reading vital signs between patients, or the same patient at intervals)
• Finger clip (2.6) (for continuous or spot reading of vital signs; only appropriate for adult or older paediatric patients. NOT recommended for use in neonatal patients)

The same pulse oximeter can be used for adult, paediatric, and neonatal patients. The alarm settings should be changed on the oximeter and appropriately sized probes must be used. Probe size will vary depending on patient age.

Normal SpO₂ for neonatal patients should be:

• 90% - 100% if not on oxygen
• 90-95% on oxygen (Alert 2.1)

If SpO₂ readings are less than 90%, the patient should be considered for supplemental oxygen therapy (see oxygen concentrator module).

Oxygen saturations, heart rate, and clinical condition should all correspond.

Management

Management of a pulse oximeter covers how to use the device in a variety of settings, including set up for a patient, patient preparation & commencement, care whilst on the device & removal of the patient from the device.

SETTING UP FOR A PATIENT

1. Follow hand washing procedures.
2. Collect:
• Pulse oximeter
• Pulse oximeter probe
• 70% alcohol solution (Alert 3.1)
• Cotton swab
3. Turn on pulse oximeter by pressing and holding the power button. (3.1) The display should turn on.

4. Connect the probe. (3.2)
• Check the shapes of the pulse oximeter port & external probe sensor. If these are not the same size, you need an adapter. This should be provided with the pulse oximeter.
• Connect the probe connector to the pulse oximeter probe port. Careful not to bend the pins.
5. Check for a red light on the probe. If the probe displays a red light, take steps to prepare patient for device. If the probe does not display a red light, follow the guidelines in Pulse Oximeter: Troubleshooting & Repair | If the pulse oximeter is turning on, but no trace is showing.
6. Clean the pulse oximeter probe thoroughly using alcohol and a cotton swab.

PREPARING A PATIENT

1. Follow hand washing procedures.
2. Always explain the purpose, risks, and benefits of a procedure to guardians BEFORE performing the procedure.
3. Collect:
• Neonatal clip or wrap probe
• Pulse oximeter
• Gauze
• 70% Alcohol
4. Select best location on patient to collect reading:
• Wrist or foot (wrap probe); fingers or toes (clip probe)
• Well perfused, warm and with intact tissue
5. Clean location with alcohol & gauze.
6. Position the patient in a neutral position (3.3) to ensure airway patency.

STARTING A PATIENT

1. Adhesive (one-use) wrap probe:
• Remove the wrap probe from its packaging and peel from its plastic base.
• Place the part of the tape with the sensor, sensor side down, on the wrist whilst palm-side up or on the sole of the foot. The wrist is only suitable for preterm babies.
• Wrap the adhesive strip around the wrist or foot to secure in place.
2. Rubber (reusable) wrap probe: (3.4)
• Place the part of the wrap probe with the sensor, sensor side down, on the wrist whilst palm-side up or on the sole of the foot. (3.5)
• Wrap the rubber connecting strip around the wrist or foot (3.6), thread through hole & tighten to secure in place. (3.7) Ensure the light and sensor are opposite each other.
3. Clip probe:
• Squeeze the tips of the clip probe to open.
• Place gently on the patient’s fingers or toes and release.

Wrap and clip probes should be firmly placed without need to be held. The probe should not be so tight that it is causing pressure on the skin or impairing circulation.

CARING FOR A PATIENT

1. Allow the patient’s trace to establish before reading SpO2 and heart rate. (3.8) These should correspond to patient’s clinical condition. If they do not correspond, reposition the probe to ensure good contact with the patient.
2. Record SpO₂ and heart rate in patient documentation. Pulse oximeters are inaccurate for readings under 70%; readings between 20% and 60% do not correlate to clinical deterioration or improvement. (Alert 3.2) A low reading should alert you to look for a problem with the probe fixation, baby or oximeter.
3. If continuously monitoring patient, periodically check the sensor site (3.9) during monitoring for evidence of skin damage.
4. Keep the parents informed of baby’s progress.

REMOVING A PATIENT

Removing the probe from the patient varies based on the type of probe in use:

1. If using an adhesive wrap probe: peel adhesive away from patient & pull probe away from patient. Disinfect probe site on patient & wrap probe with 70% alcohol if reusing.
2. If using a rubber wrap probe: unthread rubber connecting strip through the hole. Pull probe away from patient. Disinfect probe site on patient & the wrap probe with 70% alcohol.
3. If using a clip probe: press on the tips of the clip probe to open. Gently pull away from patient. Disinfect probe site on patient and clean probe with 70% alcohol.

Infection Prevention

Routine and adequate cleaning of medical devices is critical to prevent hospitalacquired infections in newborn care units. If devices and equipment are not disinfected or reprocessed promptly or adequately between patients, they may pose a significant infection risk.

GENERAL INFECTION PREVENTION

1. Clean hands with soap and water or 70% alcohol before and after assessing a patient using a pulse oximeter or handling any probes that will be used on a patient.
2. Ensure that all patient-related consumables (including probes) are new or have been cleaned thoroughly before use. Any patient-related consumables must be cleaned before they are used to assess another patient using the pulse oximeter.
3. All patient-related consumables should be stored in a clean, dry location. Keep cleaned probes separate from those waiting to be cleaned. Any cables should be loosely wrapped & secured, preventing sharp bends, pinches or kinks, which will decrease their lifetime.

DISINFECTION AFTER USE

1. Clean reusable probes with alcohol. Adhesive probes are specified for single-use; if reusing disinfect sensor with alcohol. (Alert 4.1)
2. If pulse oximeters or patient consumables (including probes) are not cleaned thoroughly before use, infection can be transmitted. Care should be taken particularly for consumables marked as single-use but are reused (such as adhesive wrap probes).
3. Between patients, wipe down the pulse oximeter with alcohol. (4.1) Be careful not to submerge or drip alcohol onto the pulse oximeter or any of its cables.

Complications

Introduction of equipment in newborn care units poses clinical and device complications for patients. Awareness of potential complications is critical to maximise patient safety.

CLINICAL COMPLICATIONS

• Misdiagnosis: a poor trace (5.1) may contribute to misdiagnosis and can result from:
• Hypovolaemia/hypotension: poor peripheral perfusion or movement may cause a false reading.
• Peripheral cyanosis/anaemia: poor oxygen delivery to the tissues, compromises measured saturation. Saturation readings below 70% are not reliable as clinical guides.
• Hypothermia: causes poor peripheral perfusion which in turn can provide an inaccurate representation of the oxygen saturation within the blood.

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• Pressure sores: if the pulse oximeter probe is attached too tightly, inappropriately or too long at one site, pressure sores may develop. The warmth of the light may irritate the skin of a premature baby which is why the probe needs regular repositioning.

DEVICE COMPLICATIONS

• Poorly fitting probes can lead to inaccurate saturation measurements: if the probe is too large for the patient, the probe will shift in place, creating issues both in terms of inconsistent measurement due to multiple contact points as well as the potential to have no direct contact points with the skin. If the probe is too small for the patient, blood flow may be constricted and the reading affected. Also, the light and sensor must be positioned opposite each other.
• Patient movement: as the patient moves, the contact point between the probe and the patient moves along the patient’s skin. This movement provides an inconsistent measurement because it samples from various contact points in the skin, rather than remaining in the same contact point of tissue.
• Strong light: if strong light (e.g., phototherapy, exam lights, or sunlight) is on a probe sensor, the light signal from the pulse oximeter probe may be drowned out by the stronger environmental light, leading to incorrect results. A cloth covering of the sensor site will protect it from bright light.
• Oximeter alarm settings: pulse oximeters may have adult, paediatric, and neonatal settings in the same device. (5.2) Pulse oximeters are usually set to a default adult setting. If the pulse oximeter is not set to neonatal parameters, alarms may sound inappropriately.

Care & Maintenance

Users are responsible for basic first-line care and maintenance to ensure equipment lasts to their potential lifetime.

POWER SOURCE

A pulse oximeter is powered by replaceable or rechargeable (6.1) batteries. If using a rechargeable device, the users should regularly charge the pulse oximeter when not in use to ensure power in the event of a power outage.

WARD LOCATION

When using the pulse oximeter, the device should be placed in a secure location to prevent drops and breakages. The device and associated probes should be stored in a clean, dry, and secure area. The device should never be placed inside a cot or bassinet.

USER PREVENTIVE MAINTENANCE

Preventive maintenance should be conducted to ensure that the pulse oximeter is in good working order for emergency use.

1. Turn on the pulse oximeter. Connect the probe and check for a red light.
2. Connect a clip probe and test readings on your finger for normal saturations (above 90%). (6.2)

Troubleshooting & Repair

Although users are not responsible for repairing their devices, there are steps that may be taken to troubleshoot first-line errors that may occur before contacting maintenance or engineering support.

All pulse oximeters have a users’ manual. These should be accessible online. If not available for download online, contact the manufacturer to request access to a copy.

References

1. Bancalari, E. & Claure, N. Oxygenation Targets and Outcomes in Premature Infants. JAMA 309, 2161 (2013).
2. Cummings, J. J., Polin, R. A. & Committee on Fetus and Newborn. Oxygen Targeting in Extremely Low Birth Weight Infants. Pediatrics 138, e20161576 (2016).
3. Manja, V., Lakshminrusimha, S. & Cook, D. J. Oxygen Saturation Target Range for Extremely Preterm Infants: A Systematic Review and Meta-analysis. JAMA Pediatrics 169, 332 (2015).
4. Polin, R. A. & Bateman, D. Oxygen-Saturation Targets in Preterm Infants. New England Journal of Medicine 368, 2141–2142 (2013).
5. Curless MS, Ruparelia CS, Thompson E, and Trexler PA, eds. 2018. Infection Prevention and Control: Reference Manual for Health Care Facilities with Limited Resources. Jhpiego: Baltimore, MD.
6. Sharma, G. Infection Prevention and Control at Neonatal Intensive Care Units. 134.
7. WHO-UNICEF technical specifications and guidance for oxygen therapy devices. (World Health Organization and the United Nations Children’s Fund (UNICEF), 2019).