Clinicians and polysomnography equipment manufacturers discuss why viewing the video feed from an in-lab sleep study can ensure quality.
Meir Kryger, MD, was unsure what could be causing a child’s oxygen readings to fluctuate during an in-lab sleep study. But when he watched the accompanying video, the Yale School of Medicine professor quickly realized the reason: The patient had been sucking on a pacifier, which caused the nasal cannula to repeatedly move in and out of the child’s nose.
Though the trend toward increasing home sleep testing continues, when in-lab polysomnography (PSG) is done, the video and audio recordings can prove invaluable to give a complete picture to sleep physicians, scorers, and sleep lab monitoring technologists.
“I look at the video in almost every study, and I find that tremendously helpful,” Kryger says, adding that he often shows patients videos of their studies. Kryger is particularly vigilant when there is unexplained motor activity, arousals, or a discrepancy between the PSG and the clinical evaluation. Many other examples of video analysis are available in Kryger’s Atlas of Clinical Sleep Medicine.
Video and audio features are particularly important when analyzing pediatric studies, sources say.
“Pediatrics specifically utilize video to validate the data they [sleep professionals] collect. The example of discovering that a cannula is being displaced due to using a pacifier is not uncommon,” says James Blevins, sleep diagnostics product manager at manufacturer Cadwell. “Getting good quality signals on pediatric patients can be challenging at certain ages, and sometimes video can give you the best perspective on what is going on when the rest of the PSG is indeterminate.”
With pediatric patients, clear video and audio can help determine whether the child’s breathing appears labored or is matching the PSG traces, Blevins says. In some cases, it can help determine whether perceived apnea, hypercapnia, or hypoxemia on the study is valid. In labs that allow co-sleeping with parents, video can help to isolate whether the parent is influencing the results of the study due to their movement or snoring. It also can be helpful to document the type of sleeping interaction that occurs between parent and child on a regular basis.
Felipe Lerida, CPSGT, customer service manager at manufacturer Neurovirtual USA, says video recordings can help sleep specialists confirm or discard potential sleep disorder diagnoses, especially for pediatric patients who sleep in odd positions.
Making the Correct Diagnosis
Certain sleep disorders can be confirmed by attaching additional sensors to the patient along with the correlation of video recording, notes Darla Lahham, RPSGT, RST, scoring service coordinator with CleveMed. “REM behavior disorder is just one example; video and audio recording captures a patient acting out dreams, and the sensors that are placed on the arms, legs, and chin record muscle movements and somniloquy. EEG electrodes will show the patient is asleep, while observing the phenomenon by video just paints a picture of what is truly going on.”
Bettina Stiles, clinical supervisor for sleep center manager SleepMed at Chest Medicine Associates in South Portland, Maine, says, “Recordings help to identify seizure activity (as compared to someone repositioning), REM behavior disorder, somniloquy, somnambulism, bruxism.” But Stiles cautions that some PSG systems do not integrate the audio and video recordings together. “It can be a challenge to get a good system that records audio and video simultaneously with the raw data PSG,” she says.
Everyday Routine Analysis
For the monitoring technologist, the video also has value during live acquisition. If an odd or unrealistic value is being displayed on the raw data, it’s possible that a monitor in the patient’s room is producing a different value than what is being recorded on the sleep study recording. “The zoom feature could be used to see what the actual monitor is showing versus what is being recorded on the acquisition,” Lahham says. “Documentation and troubleshooting would be the next steps.”
And in cases when a body position sensor is not used, “the technician could [instead] document the patient’s position from the video,” Lahham says. “The severity of apnea could be positional if a patient presents the majority of respiratory events in, let’s say, the supine position.”
Andre Puleo, director of sleep diagnostics and therapy at Vyaire Medical, says, “A sleep tech relies on the video to record accurate body position and monitor possible seizure activity that they see in the PSG tracing. It is also very useful when titrating a patient on CPAP by helping a technician see mask leaks or mouth breathing.
“In adults, video can explain if there are sudden changes in therapeutic efficacy. For example, if someone is doing very well on therapy and then suddenly starts to have events and desaturate without the normal explanations of mask leak, REM, or a change to supine sleeping position, you can use video to determine if they’ve changed the position of their neck or done something different to compromise their airway. It can help to determine the best time to enter the room to fix the signal and risk waking the patient. With the improvement of PTZ (pan-tilt-zoom) cameras, the technologist can use the camera to zoom in very closely on the patient’s face to determine whether a cannula is still placed correctly or not.
“Video is also significant to validate whether the body position sensor is working correctly. It is also very helpful for recording techs to be able to review back through recorded video while running the study to determine where the position change occurred and appropriately mark it when the sensor misses it.”
Puleo adds that occasionally there can be artifact in the PSG signals; sometimes the video houses evidence of its cause.
Michael Rack, MD, says he reviews the video when the initial analysis gives cause to do so. “In general, I only check the patient’s video if I am unsure of his body position or if I think the techs might have marked it incorrectly,” he says. “For example, if there is a sudden unexplained worsening of OSA [obstructive sleep apnea], I will check the video to see if the techs missed a shift to the supine position.”
Video recordings can be important in ensuring patient and sleep lab employee security throughout the duration of the appointment, especially since sleep studies typically take place during times when there are not many people in the facility. “Notifying a patient that everything is being recorded upon arrival until they depart helps create a professional and safe atmosphere,” Lahham says.
Ultimately, video is about patient safety and ensuring a quality study, concludes Edmund Shaw, product manager at Philips Sleep Diagnostics. He says, “While a PSG captures a wealth of data, the waveforms are not going to tell you if a patient has fallen out of bed or adjusted his position in a way that might affect the results.”
Peter Blais, RPSGT, is a registered sleep technologist who splits his time between Maine and Florida.