Pulse Oximetry (Pediatric) - CE/NCPD

ALERT

A pediatric patient with profound anemia may have a normal oxygen saturation level and still be hypoxemic.

OVERVIEW

Pulse oximetry provides a noninvasive, accurate estimate of arterial oxygen saturation. Hemoglobin (Hgb) saturated with oxygen absorbs light differently than unsaturated Hgb, and the pulse oximeter measures the amount of absorption and uses it in the calculation of the ratio of saturated Hgb to total Hgb (Figure 1). The pulse oximeter monitor displays the ratio as a percentage.

The patient’s oxygenation status depends on the amount of Hgb and on how well it moves throughout the body and how easily oxygen leaves the Hgb and enters the cells. Normal pulse oximetry values vary by age and condition. The generally accepted range is more than 94% unless the patient has anemia.^{undefined#ref6">6} Probes come in infant, pediatric, and adult sizes. Clip-on probes are primarily used for spot checks, and circumferential tape probes are primarily used for continuous monitoring (Figure 2).

The dynamics of the oxyhemoglobin dissociation curve (ODC) include (Figure 3):

A shift to the right in the ODC means the Hgb’s affinity for oxygen has decreased at the alveolar level. The Hgb readily releases oxygen at the cellular level.
A shift to the left in the ODC means the Hgb’s affinity for oxygen has increased at the alveolar level. Oxygen binds more tightly to the Hgb and is released less readily at the cellular level.

In efforts to reduce alarm fatigue and align with The Joint Commission safety goal of reducing patient harm caused by clinical alarm systems, the use of continuous pulse oximetry is being evaluated and deimplemented at some children’s hospitals on acute care units.^1,3,5 Continuous pulse oximetry is the largest alarm parameter burden and a large contributor to alarm fatigue.¹ Setting the appropriate alarm parameters decreases the number of false alarms and reduces alarm fatigue.

Inaccurate readings can occur in these patients:⁴

Pediatric patients with decreased Hgb concentrations (from anemia or hemorrhage) can have a normal oxygen saturation and still be hypoxemic. Even though the Hgb may be fully saturated, the patient does not have sufficient Hgb to carry enough oxygen to meet the body’s needs.
Pediatric patients with decreased perfusion (from shock, bradycardia, or cardiovascular disease) may start with a normal oxygen saturation, but because of decreased blood flow, the Hgb is in prolonged contact with the cells. The cells’ oxygen demands are increased, and the Hgb is stripped of oxygen, taking longer to return to the lungs for reoxygenation.

Pulse oximetry readings are altered by:⁴

Incorrect placement of the sensor
Movement, causing artifact
Intravascular dyes
Low perfusion states
Dark skin pigmentation
Vinyl or gel nail polish and artificial nails
Severe anemia
Smoke inhalation or carbon monoxide poisoning
Sickle cell anemia vasoocclusive crises
Methemoglobinemia
Sulfhemoglobinemia
Severe hyperbilirubinemia
Hypothermia

SUPPLIES

See Supplies tab at the top of the page.

EDUCATION

Provide developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, and overall neurologic and psychosocial state.
Explain the patient’s underlying condition, the reasons for pulse oximetry monitoring, and the meaning of the oxygen saturation reading.
Review the pulse oximeter alarm and explain the causes of false alarms, such as movement.
Encourage questions and answer them as they arise.

ASSESSMENT AND PREPARATION

Assessment

Perform hand hygiene before patient contact. Don appropriate personal protective equipment (PPE) based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
Introduce yourself to the patient and family.
Verify the correct patient using two identifiers.
Assess the patient’s developmental level and ability to interact.
Assess the pertinent medical history and current condition predisposing the patient to alterations in oxygenation, ventilation, and acid-base balance.
Assess the patient’s respiratory status, including respiratory rate, work of breathing, and breath sounds.
Assess the patient for signs and symptoms of inadequate oxygenation and ventilation.
Note the patient’s serum Hgb level.
Assess the patient for conditions that prevent accurate monitoring of oxygen saturation with a pulse oximeter, such as carbon monoxide poisoning and nitric oxide administration.
Assess the intended probe placement site for adequate perfusion, skin integrity, and nail polish.
Assess the patient’s and family’s understanding of the reasons for and the risks and benefits of the procedure.

Preparation

Plug the oximeter into a grounded outlet (if the patient is not on a continuous bedside monitor with pulse oximetry monitoring), plug the cable into the oximeter or oximetry box, and plug the probe into the cable.
Set the appropriate alarm parameters according to the patient’s age and diagnosis or per the practitioner’s order.

PROCEDURE

Perform hand hygiene. Don appropriate PPE based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
Verify the correct patient using two identifiers.
Explain the procedure to the patient and family and ensure that they agree to treatment.
Select an appropriate oximeter probe site (Figure 2). Preferred sites for a neonate include the foot and hand; for an infant, the great toe, ball of the foot, palm of the hand, earlobe, and wrist; and for an older pediatric patient, the index finger or another digit.
Rationale: Site selection can affect the accuracy of pulse oximeter readings. For instance, in pediatric patients with cyanotic heart disease, a preductal saturation can be obtained in the right arm, and a postductal saturation may be obtained in the left arm or in either foot.

Avoid sites distal to arterial lines and noninvasive blood pressure cuffs and sites on the same side as a Blalock-Taussig shunt.
Apply the probe to the patient, ensuring that the light source is directly opposite the photodetector and the probe fits snugly without any gaps between it and the skin.
Rationale: For accurate saturation measurement, the light source and the photodetector must be directly opposite each other.

Do not apply the probe so tightly that it interrupts blood flow to or from the site. Tissue perfusion can be impaired by circumferential restriction of arterial flow. Venous return and venous congestion may lead to venous pulsations and false readings.
Turn the alarms on and ensure the waveform returns.
Verify the accuracy of the pulse oximeter reading by correlating it with the patient’s heart rate. Analyze the size and shape of the waveform and the height and fluctuation of the graphic display bar.
Rationale: Correlating the reading with the patient’s heart rate ensures the accuracy of the pulse oximeter value. The patient’s measured electrocardiogram or palpated heart rate should match the heart rate displayed by the pulse oximeter.

If the oximeter displays the pulse wave graphically, the pulse waveform should resemble an arterial waveform without a dicrotic notch. If the pulsatile flow past the probe is sluggish, the waveform may be dampened, and the reading may be incorrect.
Discard supplies, remove PPE, and perform hand hygiene.
At the end of the procedure, ensure that all choking hazards (e.g., probe wrappers) are removed from the patient’s linens and placed in the appropriate receptacle.
Document the procedure in the patient’s record.

MONITORING AND CARE

Assess the patient’s physiologic stability, including vital signs, respiratory status, and clinical appearance.
Rationale: Pulse oximetry provides only one piece of information. The patient’s physiologic status must be considered to gain a complete understanding of the patient’s condition.

Reportable conditions: Hypoxia, including decreased level of consciousness; tachypnea and tachycardia; increased work of breathing; cyanosis; decreased oxygen saturation level
Assess the probe site for breakdown and rotate the site at least twice daily.² This is especially important when using circumferential probes for continuous monitoring.
Rationale: Skin probes can cause medical device–related pressure injuries. Certain conditions, such as low perfusion states, norepinephrine and other vasoconstrictive infusions, hypoxia, hypotension, prolonged probe contact, and hypothermia, can increase the likelihood of injury.

Reportable conditions: Skin discoloration, decreased capillary refill time, skin breakdown at or distal to the probe site

EXPECTED OUTCOMES

Pulse oximetry saturation readings correlate with measured saturation from arterial blood gas analysis.
Patient’s measured electrocardiogram or palpated heart rate matches the heart rate displayed by the pulse oximeter.
All periods of desaturation are identified, and appropriate action is taken.
Number of false alarms is reduced.
Skin integrity is maintained.

UNEXPECTED OUTCOMES

Pulse oximetry saturation readings do not correlate with measured saturation from arterial blood gas analysis.
Patient’s measured electrocardiogram or palpated heart rate does not match the heart rate displayed by the pulse oximeter. Patient decompensates without identification of changes in pulse oximetry.
Excessive motion or decreased tissue perfusion interferes with proper functioning of the pulse oximeter.
Pulse oximeter probe causes a medical device–related pressure injury.

DOCUMENTATION

Pulse oximetry readings
Amount and delivery method of supplemental oxygen (if used)
Patient’s physical assessment findings
Patient’s response to interventions
Condition of probe site
Rotation of probe site
Episodes of desaturation
Unexpected outcomes and related interventions
Education

REFERENCES

Berg, K.J. and others. (2023). Reducing the frequency of pulse oximetry alarms at a children’s hospital. Pediatrics, 151(5), e2022057465. doi:10.1542/peds.2022-057465
Carroll, A.L., Palokas, M., Linnell, S. (2023). Oxygen saturation probe-related pressure injury prevention in children on an inpatient pediatric unit: A best practice implementation project. JBI Evidence Implementation, 21(1), 58-67. doi:10.1097/XEB.0000000000000339
Faerber, J.A. and others. (2023). Sustainment of continuous pulse oximetry deimplementation: Analysis of eliminating monitor overuse study data from six hospitals. Journal of Hospital Medicine, 18(8), 724-729. doi:10.1002/jhm.13154
Fetzer, S. (2022). Chapter 5: Vital signs. In A.G. Perry and others (Eds.), Clinical nursing skills & techniques (10th ed., pp. 68-107). St. Louis: Elsevier.
Joint Commission, The. (2024). National Patient Safety Goals for the hospital program. Retrieved August 21, 2024, from https://www.jointcommission.org/-/media/tjc/documents/standards/national-patient-safety-goals/2024/npsg_chapter_hap_jan2024.pdf
Topjian, A.A. and others. (2020). Part 4: Pediatric basic and advanced life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation, 142(16 Suppl. 2), S469-S523. doi:10.1161/CIR.0000000000000901 Retrieved August 21, 2023, from https://www.ahajournals.org/doi/10.1161/CIR.0000000000000901

ADDITIONAL READINGS

Andrist, E. and others. (2022). Association of race with pulse oximetry accuracy in hospitalized children. JAMA Network Open, 5(3), e224584. doi:10.1001/jamanetworkopen.2022.4584

Clinical Review: Marlene L. Bokholdt, MS, RN, CPEN, TCRN

Published: October 2024