When it comes to pediatric sleep studies, transcutaneous monitoring plays a crucial role in providing optimal care for young patients. At the Nemours Children’s Hospital Pediatric Sleep Center in Orlando, Florida, CO2 monitoring is integrated into therapist-driven protocols to ensure accurate diagnosis and optimal management of sleep-disordered breathing for pediatric patients.
This article will explore how we use CO2 monitoring in our pediatric sleep lab at Nemours Children’s to diagnose and guide patient therapy for sleep-disordered breathing, important considerations to keep in mind, and a series of short case studies to demonstrate practical applications in various clinical scenarios.
Infrastructure and Expertise
Although not routinely measured during adult sleep studies, CO2 is recorded more often than not in pediatric sleep studies—and there are specific guidelines and standards that need to be considered and addressed when implementing CO2 . Understanding the protocols and standards for pediatric sleep studies is essential in utilizing CO2 monitoring effectively.
First and foremost, it’s crucial to have the proper resources and expertise available to support the integration of CO2 monitoring in pediatric sleep studies. Our nine-bed pediatric sleep lab is open seven nights a week (except holidays) and has a robust infrastructure that includes:
- 10 to 11 full-time technologists overnight.
- Seven portable units for electroencephalogram (EEG)/inpatient sleep studies.
- Two full-time day scoring technologists and a clinical educator.
- A pediatric sleep lab manager, a dedicated scheduler for sleep/EEG departments, and two sleep medicine/pulmonary physicians.
Our lab had conducted more than 2,200 pediatric sleep studies as of 2023. Due to the medical complexity/acuity of our patients as well as state guidelines regarding the care of patients with invasive ventilation, our team consists primarily of registered respiratory therapists (RRTs) who are dually credentialed as registered polysomnographic technologists (RPSGTs). Their dual credentialing is a huge benefit to our lab, enabling us to provide specialized care, tailored to the unique needs of pediatric patients undergoing transcutaneous monitoring during sleep studies.
Their respiratory expertise, skills, and knowledge are invaluable, particularly their ability to conduct ventilator titrations for patients receiving both invasive and noninvasive ventilatory support without requiring hospital admission. This streamlined approach benefits families by reducing the need for extended hospital stays and also contributes to cost savings for the hospital.
These RRTs/RPSGTs are also adept at downsizing tracheal tubes, implementing minimal leak techniques, and recognizing respiratory distress in pediatric patients. Their expertise extends to providing essential support during staff shortages and maintaining inpatient skills, ensuring continuous, high-quality care.
Patient Population
At our pediatric sleep lab, we see a wide range of patients—from two days old to 18 years (with some exceptions approved by the chief medical officer). A few of the most prevalent diagnoses we see include enlarged tonsils and adenoids, snoring, and obstructive sleep apnea (OSA).
Additionally, we frequently conduct sleep studies for neuromuscular patients, including those with spinal muscular atrophy, necessitating complex respiratory ventilation and titrations. Patients with hypotonia, respiratory failure, and those requiring oxygen, continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), or volume ventilation also form a significant portion of the patient population.
Approximately 70% of our patient population comes from otolaryngologists (ENTs) and pulmonary providers. However, a substantial number of patients are referred from multidisciplinary specialty clinics, including specialists in neurology, cardiology, endocrinology, and nephrology. The increasing role of pediatricians in the community, aided by the ability to record and share symptoms, has also led to a significant rise in patient referrals to the lab.
Pediatric vs. Adult Sleep Study Guidelines
Pediatric sleep studies have specific guidelines and standards that significantly influence the development of protocols within pediatric sleep labs. Understanding the differences in event duration, staging, and hypoventilation definitions between pediatric and adult patients is essential for accurately interpreting and responding to transcutaneous monitoring data in pediatric sleep studies.
Some of the main scoring rule differences include:
- Event duration: 10-second events are replaced by the length of two baseline breaths.
- Mixed apnea: The order of the central and obstructive component does not matter.
- Staging: For infants who are 0 to 2 months old, infant staging is used (W, N, R, T)
- Hypoventilation
- Pediatrics: CO2 greater than 50 mmHg for 25% of the night
- Adults: PCO2 > 55 mmHg for > 10 minutes or an increase of > 10 mmHg for 10 minutes (over 50)
Developing CO2-Driven Protocols
Implementing CO2 monitoring in pediatric sleep studies involves developing specific protocols and policies tailored to the unique needs of young patients. These protocols are essential for accurately diagnosing and treating pediatric patients undergoing transcutaneous monitoring in sleep studies. Below are some example protocol excerpts of PCO2 monitoring in our sleep lab protocols:
Hypoventilation
Specific actions are initiated when a patient’s CO2 values exceed 50 for more than 25% of the total sleep time. These actions include assessing the sensor’s functionality, replacing the machine if necessary, and considering the patient’s history to determine the cause of high CO2 levels. If hypoventilation is confirmed, interventions such as initiating BiPAP or transitioning from CPAP to BiPAP are implemented based on predefined criteria.
CPAP titration
If maximum pressure of 15 cmH20 is reached and PCO2 remains > 50 mmHg for >25% of time on CPAP and/or obstructive events continue at 15 cmH2O, BiPAP should be initiated per protocol.
BiPAP titration
For patients diagnosed with restrictive lung disease, obesity hypoventilation syndrome, neuromuscular disorders, and respiratory failure, volume ventilation is initiated after reaching maximum BiPAP pressures, based on the patient’s age:
- PCO2 > 50 mmHg for > 25% of time on max pressures or
- SpO2 < 90% for > 5 minutes in 2 hours due to obstructive events.
Capnography Study Considerations
For capnography studies, a failed study is determined if the patient’s CO2 levels remain above 50 mmHg for more than 25% of the total sleep time after four hours. In such cases, considerations for decannulation are made, and the patient may be scheduled for a repeat study after a certain period. Additionally, other symptoms and work of breathing are also evaluated to ensure comprehensive assessment and decision-making.
CO2 Monitoring in Practice
Here are just few short case studies that demonstrate how CO2 monitoring is able to support our pediatric sleep lab in diagnosing and managing sleep-related breathing across a range of clinical diagnoses and situations:
Case Study 1. Severe OSA with Refusal of PAP
In a notable case, a 5-year-old patient presented with sleep apnea and snoring, and the parents were hesitant to pursue CPAP therapy, refusing to initiate the treatment for their child. Consequently, a diagnostic study was performed to validate the severity of OSA and its impact on the child.
Case Study 2. Down Syndrome with Hypoxia
Let’s explore a case involving a 15-month-old patient with Down syndrome, hypoxia, snoring, and hypotonia, presenting a history of severe hypoxemia with a high index of 22. Upon placing oxygen on the patient, the sensor experienced frequent disconnections, requiring constant recalibration and reattachment to maintain CO2 monitoring. The dedicated efforts of the technologists were crucial in ensuring continuous transcutaneous monitoring for this patient.
Case Study 3. Severe OSA with CPAP to BiPAP Titration
Managing severe OSA in pediatric patients requires careful monitoring and titration of therapy to ensure optimal outcomes. Let’s delve into a compelling case study involving a six-year-old patient with enlarged tonsils and adenoids, a history of snoring, and allergic rhinitis, presenting with a severe AHI of 12.
During the assessment, both transcutaneous and end-tidal monitoring were employed. Despite some intermittent dropouts, the transcutaneous monitor effectively captured CO2 levels, correlating with obstructive events and demonstrating consistent trends throughout the night. In contrast, the end-tidal monitor experienced washout and dropouts, impacting the reliability of the readings.
Titration challenges and BiPAP implementation:
- Initial CPAP settings of 8 over 4
- Immediate CO2 rise and desaturations
- Tight titration with addition of rate to BiPAP
Upon observation, the patient experienced immediate CO2 climbing and desaturations while on CPAP, necessitating tight titration. The technologist made real-time adjustments, transitioning the patient to BiPAP with added rate support to address the high CO2 values and optimize ventilation.
Case Study 4. Severe OSA with Chronic Respiratory Failure
In this case study, a 15-year-old patient with OSA, spinal fusion, chromosome abnormality, and a history of chronic respiratory failure was scheduled for overnight evaluation. The patient was already on BiPAP, initially set at 8 over 4. However, the patient’s CO2 levels quickly escalated, reaching as high as 77.
Subsequent recalibration of the machine and a switch to volume ventilation showed a downward trend in CO2 levels, albeit never dropping below 50, indicating potential CO2 retention. The patient’s most ideal setting was identified to be on volume ventilation, with a low CO2 level of 56 for the night, showcasing a positive outcome in managing the patient’s chronic respiratory failure.
Case Study 5. Tracheostomy with Ventilator Titration
During a ventilator titration for a 19-month-old patient with a history of bronchopulmonary dysplasia, nocturnal respiratory insufficiency, pulmonary hypertension, and developmental delay, both end-tidal and transcutaneous CO2 monitoring were utilized.
While the end-tidal CO2 trend showed fluctuations and dropouts, the transcutaneous monitoring demonstrated a steady trend until it was inadvertently turned off. Despite the intermittent drop in transcutaneous monitoring, the overall trend remained favorable, allowing for successful down titration of the ventilator based on the CO2 levels.
In Summary
Pediatric sleep laboratories are special places—they require additional care and attention to pediatric-specific protocols. Dually credentialed technologists can provide valuable expertise in respiratory care when needed. A sleep lab may benefit from staffing dually credentialed RRTs/RPSGTs to treat complex respiratory patients and perform ventilator titrations.
Integrating CO2 monitoring into therapist-driven protocols helps to ensure accurate diagnosis and advanced care therapy for pediatric patients. In both routine and complex pediatric sleep studies, CO2 monitoring can aid pediatric sleep lab professionals in effectively assessing, identifying, and treating patients with sleep-disordered breathing.
Sidebar
Pros and Cons of End-Tidal CO2 Monitoring vs. Transcutaneous CO2 Monitoring
It is worthwhile to compare the two techniques for CO2 monitoring—end-tidal and transcutaneous—in order to decide which approach is best suited for the patient. Understanding the differences between these two monitoring methods is essential in selecting the most appropriate monitoring approach and optimizing care for pediatric patients undergoing transcutaneous monitoring in sleep studies.
The table below outlines some of the main advantages and limitations associated with each method.
| Pros | Cons | |
| End-Tidal CO2 Monitoring | • Flow channel for events
• Works in most positions • No false high readings • Lower cost
|
• Mouth breathing and congestion can lead to flow dropouts, affecting the reliability of the readings.
• Uncomfortable • Interference from O2 or PAP can dilute or even eliminate readings. • Tubing clogs with secretions. • Unavailable for purchase |
| Transcutaneous CO2 Monitoring | • Comfortable
• Reliable trend plots/values • No false low readings • Not affected by O2, PAP, or ventilation therapy, making them suitable for a wide range of patients. |
• Higher supply costs
• Occasional high ratings • Sensor/cable can be damaged and costly to replace
|
By Lisa DeGuzmen
