Pulse Oximetry

CLINICAL GUIDELINES

Pulse oximetry may be performed by a respiratory therapist (RT) or registered nurse (RN), licensed practical nurse (LPN) or unlicensed assistant personnel (UAP) per healthcare prescriber’s orders or as an acute emergent evaluation of child’s status without a direct healthcare prescriber’s order (Chart 94-1). When pulse oximetry is completed by a UAP, and variance from baseline or deviance from previous measurement is reported to the licensed caregiver.
All children receiving continuous pulse oximetry are assessed by an RT or RN every 2 hours or more frequently as indicated by the child’s status. Assessment should include respiratory status, pulse oximetry reading, skin integrity at the site, circulation distal to the sensor site, and knowledge of the child’s baseline diagnosis and status.
All pulse oximetry intermittent checks are performed and evaluated by an RT or an RN.
The child receives pulse oximetry monitoring as per healthcare prescriber’s order, which specifies frequency (continuous or intermittent check). Orders may be written as guidelines to adjust oxygen administration based on pulse oximetry saturation level.
Continuous pulse oximetry monitoring will be employed on all children receiving sedation for diagnostic and therapeutic procedures, or when direct observation of the child may be difficult.
Acceptable ranges for the child’s saturation levels are prescribed by the healthcare provider or per unit protocol. Parameters are based on the child’s underlying clinical condition and past medical history. Normal saturation levels for healthy children are considered to range between 97% and 99% at sea level. Ranges for neonates and young infants are 93% to 100%.
Routine pulse oximetry is performed on asymptomatic newborns after 24 hours of life, but before hospital discharge to assist in the detection of critical congenital heart disease (CCHD).
All children on pulse oximetry will have appropriately sized oxygen-delivery devices readily available for emergency access by healthcare personnel (e.g., bag-mask, oxygen tubing, oxygen source).

CHART 94-1 Indications for Pulse Oximetry

Children at high risk for adverse events, apnea/bradycardic spells, cyanotic spells, or respiratory distress/failure
Children having an asthmatic exacerbation
Children hospitalized with pneumonia
Children with acute bronchiolitis (intermittent monitoring preferred)
During neonatal resuscitation
A screening tool for early detection of asymptomatic newborns with critical congenital heart disease (CCHD)
Children receiving supplemental oxygen administration
Children in the intensive care unit
Children receiving mechanical ventilation
Children undergoing sedation for procedural and therapeutic procedures
Children receiving patient-controlled anesthesia
Children with seizures
High-risk postoperative patients
Postextubation for 48 hours or longer as indicated by the healthcare prescriber
Transportation of all mechanically ventilated children
Children being weaned from oxygen therapy or mechanical ventilation

CHILD AND FAMILY ASSESSMENT AND PREPARATION

Identify the child and explain the purpose of the equipment to the child and family on the family caregivers’ role in assisting maintenance of proper placement of the sensor.
Assess pertinent history, focusing on events that may have precipitated respiratory distress. Also assess for recent intravascular use of lipids or dyes, which could interfere with the accuracy of pulse oximetry readings.
Assess physical findings, including respiratory rate and effort, use of accessory muscles, shape of chest, position of child (i.e., sitting, standing), breath sounds, perfusion, vital signs, and presence and degree of restlessness and anxiety. Also check for an elevated bilirubin level, if available, which may falsely lower oxygen saturation readings.
Ensure that the child’s fingernail beds are clean and free of nail polish to decrease interference in providing accurate oximetry readings (Chart 94-1).

PROCEDURE
Performing Pulse Oximetry

Steps	Rationale/Points of Emphasis
1 Perform hand hygiene.	Reduces transmission of microorganisms.
2 Gather the necessary equipment and supplies. Plug pulse oximeter monitor into wall outlet.	Promotes efficient time management and provides an organized approach to the procedure. Facilitates initiating the monitoring with minimal delays. Base sensor selection on the child’s age, size, and preferred site to be used.
3 Select the appropriate sensor and attach the cable to the pulse oximeter monitor.	Base sensor selection on the child’s age, size, and preferred site to be used.
4 Select the appropriate oximeter site (Chart 94-2 and Figures 94-1-94-3). Figure 94-1 Position the sensor on the great toe with the light source on one side and the sensor on the other, facing each other. The cable should extend toward the heel.	Transmission pulse oximetry allows measurement of the light transmitted through a pulsating arterial vascular bed to calculate the percentage of hemoglobin saturated with oxygen (SaO₂). Reflection pulse oximetry has the light source and the photodetector located on the surface and can be applied to any accessible skin site. Avoid placing the sensor over thick skin, nail polish, false nails, extremities that are moved excessively by the child, and areas where perfusion is known to be poor (Chart 94-3 ). These sites are least restrictive and easiest to maintain in infants. Figure 94-2 Placement of the sensor on the forehead is effective because blood supply to the forehead precludes minimal vasoactivity.
Figure 94-3 When using the finger, position the sensor with the light source centered on the fingertip.
5 Secure the sensor to monitoring site with the light source on one side of the tissue pad and the sensor on the other, facing each other. For optimal performance, keep the sensor site at the level of the heart. Research has indicated that during neonatal resuscitation efforts, applying the sensor to the infant before connecting the sensor cable to oximeter resulted in quickest acquisition of accurate heart rate.	The sensor must be positioned so that the emitter (light source) and the photodetector are opposite each other with 5 to 10 mm of tissue between them. Failure to position and to secure properly may cause motion artifact and thus incorrect SaO₂ measurement. Taping too tightly may impede circulation, causing an incorrect reading and potential damage to the child’s fragile skin.
6 Tape sensor in place, loosely but securely.	Failure to position and to secure properly may cause motion artifact and thus incorrect SaO₂ measurement. Taping too tightly may impede circulation, causing an incorrect reading and potential damage to the child’s fragile skin.
7 Cover sensor site with an opaque material.	Excessive light, such as from phototherapy, direct sunlight, or excessive ambient lighting, can interfere with the sensor’s ability to produce an accurate reading.
8 Turn pulse oximeter monitor on and verify that the child’s apical pulse rate corresponds to the pulse rate shown on the monitor. If machine has a visual waveform display or other bar graph indicator to indicate that an accurate signal is being received, ensure that the reading is present at the highest level and that the waveform shows a good trace.	Lack of correlation between the child’s actual pulse rate and pulse rate shown on the monitor indicates the unreliability of the SaO₂ findings. The reliability of the SaO₂ findings will be greater if the waveform display is reading at a high, as opposed to a low, level.
9a Alarm limits should be determined in conjunction with the healthcare prescriber and take into consideration the child’s age, underlying condition, and past history of normal parameters for that child.	When alarms are set correctly, the oximeter can detect hypoxemia before the child becomes cyanotic and the nurse can be alerted to a downward trend and deterioration in the child’s status. Although oxygen saturation of 95% and 96% are adequate (i.e., not requiring acute oxygen therapy), these values are associated with higher rates of airway pulmonary or cardiovascular system involvement and should be considered potentially abnormal.
9b Program alarm limits according to the manufacturer’s instructions. Once alarm limits are set, these will default to the manufacturer’s settings for the monitor when the monitor is switched off and then on again. Each time the monitor is turned on, the alarm limits must be rechecked.	Set low-saturation alarm at 92% in most cases. This allows for early intervention and treatment if oxygen is to be delivered once a 90% saturation level is observed. Low-pulse alarms are often set as follows, based on the child’s age: <1 month—80 beats/minute 1-3 months—70 beats/minute >3 months—60 beats/minute
10 Determine with the healthcare prescriber when oxygen should be administered or increased based on SaO₂ values and the child’s clinical presentation.	Oxygen should be given if the SaO₂ values are 90% or below. This may vary depending on the child’s underlying medical condition (e.g., cardiac anomaly). Pulse oximetry saturation for newborns is lower at higher altitudes than at sea level.
11 Dispose of waste in appropriate receptacle. Perform hand hygiene.	Standard precautions. Reduces transmission of microorganisms.
12 When responding to alarms, assess for the following: Respiratory distress, failure, or insufficiency (note child’s color, respiratory effort, and rate) Pulse rate on the oximeter corresponds with child’s pulse rate monitor or apical heart rate Oxygen equipment is functioning properly Good adhesion of the sensor to the skin site Light source on the sensor is functioning, and oximetry cables are properly connected Opaque cover is in place over the sensor Limb being used is not being moved excessively Sensor is at the level of the heart Hypothermia Hypotension Vasoconstriction Diaphoresis	Pulse oximetry is used as an early detector of hypoxemia in children. Children have lower pulmonary reserves than adults and can decompensate more quickly if oxygen levels are not stabilized. All the assessments indicated here, with the exception of respiratory failure or insufficiency (which warrants immediate intervention by, and notification of, the healthcare prescriber), can produce inaccurate readings and false alarms and need to be corrected once discovered. caREminder Readings from the oximeter should always be interpreted in association with the child’s clinical condition. Strong lighting such as phototherapy lights will interfere with accurate readings.
13 Rotate the sensor once a shift or per institutional policy.	Decreases the risk for tissue breakdown.
14 When pulse oximetry is no longer needed, remove sensor. Assess skin under sensor for any redness or skin breakdown. Return equipment to appropriate area to be cleaned and place disposable equipment in trash receptacle. Perform hand hygiene.	Monitor skin integrity. Standard precautions. Reduces transmission of microorganisms.