A patient with severe sleep apnea was found to be not sufficiently treated by Inspire.

Background

We present a 47-year-old male with a BMI of 29.7 and a history of obstructive sleep apnea. The patient was previously diagnosed with severe obstructive sleep apnea (AHI: 54) and was initially placed on CPAP. After failing to adhere to CPAP due to comfort issues, the patient was prescribed Inspire as an alternative therapy. Inspire is a device that stimulates the hypoglossal nerve in the neck, which helps maintain tone of the tongue and upper airways during sleep. This helps reduce airway obstruction.

The patient’s Inspire stimulation setting was titrated to the maximum setting. The patient returned to Inspire multiple times as he felt the device was not working due to continued symptoms consistent with severe obstructive sleep apnea. Symptoms included excessive daytime sleepiness with an inability to stay awake while driving, continued breathing obstructions, severe cognitive issues, and hypertension.

Inspire recommended that he see a specialist to investigate if hyoid suspension surgery would be complementary to his Inspire therapy. Hyoid suspension was deemed unlikely to be effective for improving his sleep apnea. The patient was then referred to a specialist for Maxillomandibular Advancement (MMA) Surgery, which was assessed to be a better option. The patient purchased a Wesper wellness device to better understand the severity of his breathing while using Inspire and to provide data for the MMA specialist.

Explanation of metrics:

• Breathing events—Moments of increased respiratory effort, which include reduced airflow and prolonged breathing stoppages. 
• Snoring %- Percentage of snoring detected for the duration of the test 
• Total sleep time - Total accumulation of sleep in minutes. 
• Sleep quality score - Takes into consideration both sleep duration and sleep efficiency. 
• Awakenings - The total number of awakenings during the testing period. 
• Apnea/Hypopnea Index (AHI) - the combined average number of apneas and hypopneas that occur per hour of sleep
• Respiratory Event Index (REI) - the total number o3. Oxygen Desaturation Index (ODI) - the number of times per hour of sleep that the blood oxygen level drops by ≥ 3% from baseline
• Mean SPO2: The average blood oxygen saturation score 
• Minimum SPO2: The lowest blood oxygen saturation score

The patient has completed 10 tests while using his Inspire device over a one-month period. 

Findings

The patient’s original diagnostic test calculated an AHI of 54. With the use of Inspire at its maximum setting, the patient’s average number of breathing per hour across 10 Wesper tests was 29 (min/max: 15/42). While breathing events are not a 1:1 ratio to AHI, breathing event severity directly correlates to AHI severity in clinical settings, when measured against PSG. This means that is the patient’s breathing event severity was considered moderate (15-30 events per hour) to severe >30 events per hour), we would expect to see the patient’s AHI fall within that severity range.

Since the patient’s average breathing event score was 29 and 50% of his Wesper tests placed his breathing events in the severe range, we would expect his AHI to fall within the severe range with additional diagnostic testing. 

In addition to the patient’s breathing, we also tested sleep metrics to assess how his OSA was affecting sleep quality.

The patient’s average total sleep time was 6.6 hours (low)

The patient’s average sleep quality score was 57.3% (low)

The patient’s average prolonged nighttime awakenings was 6 (high)

The patient’s Wesper teats concluded that his Inspire device was only offering moderate improvements, as indicated by continued poor breathing quality and reduced overall sleep quality. It was therefore determined by the Wesper Sleep Expert that additional therapy, such as possible MMA surgery, was necessary to treat the patient's severe OSA if CPAP was not an option.

Conclusion

Longitudinal Wesper testing confirmed the patient’s assumption that their Inspire therapy was not sufficiently correcting their severe OSA. The patient’s Wesper data was shared with their MMA specialists. The patient has been cleared for MMA surgery, and the patient will be retesting with Wesper after surgical recovery. This case study demonstrates the importance of confirming the treatment efficacy of therapies for OSA treatment and monitoring the patient in the long term to ensure that therapy failures are addressed in a reasonable timeframe.

Update (February 2023)

In February 2023, approximately 7 months after the user initially started using Wesper, he was referred to a new sleep specialist for a new PSG to confirm that his sleep apnea was still poor while using Inspire. The new PSG was ordered specifically because

1. Wesper data showed a high level of breathing events while the patient used Inspire at its highest setting.
2. Before MMA surgery is considered, a new titration study for his Inspire device must be conducted.
   

The user shared his new PSG results with the Wesper sleep expert to evaluate. The pre-titration PSG indicated that with Inspire, the patient had an AHI of 26.8 and a sleep efficiency of 41%. SPO2 was not provided.

Additionally, the user upgraded from Wesper’s 2-component test to the 3-component test during the same time period and ran two Wesper tests with the pulse oximeter. The two 3-component tests showed that their sleep apnea was still within the moderate to severe range despite using Inspire.

His average AHI between the two tests was 27.55 with the highest recorded AHI at 37.3. The average ODI was 42.3 with the highest recorded ODI at 62.4. The average mean SPO2 was 92.5% with the lowest recorded mean SPO2 at 91%. The average minimum SPO2 was 73% with the lowest recorded minimum SPO2 at 72%. The Wesper tests agreed with the results of the patient’s overnight PSG.

Interestingly, Wesper also revealed that his sleep apnea severity was largely dependent on sleeping position, with an average supine AHI of 37.8 (Max 50.7). Side sleeping, however, resulted in an average AHI of 9.68, demonstrating that he may be a candidate for positional therapy in combination with his Inspire device. However, on consultation, the user revealed he’s intolerant to positional therapy as it causes him pain issues.

The patient is currently awaiting a second sleep study in April 2023 for additional titration of his Inspire device. If additional titration is unsuccessful, the patient will be considered for MMA surgery. The patient plans on continuing to test with Wesper to collect more data. 

The patient credits Wesper for demonstrating that his Inspire device was not sufficiently correcting his severe sleep apnea and has helped put him on a pathway to better therapy.