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Misleading sleep-diagnostic results in a patient with variable nasal airflow obstruction.

Spurling KJ, Perks JL, Makker HK - Sleep Sci (2015)

View Article: PubMed Central - PubMed

Affiliation: Respiratory Physiology Department, North Middlesex University Hospital, London, UK.

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A 23 year old man was referred to our sleep clinic with a history of loud snoring, witnessed apnoeas and waking with a dry and sore throat... A Type III home sleep study was performed using Embletta Portable Diagnostic System (Stowood Scientific Instruments, Oxford UK) and Somnologica software (Embla, Broomfield, USA) for analysis, due to the comparability in diagnosing adult patients with a high probability of moderate to severe obstructive sleep apnoea... Initial results indicated severe obstructive sleep apnoea with an apnoea/hypopnoea index (AHI) of 38 events per hour, the majority of which were obstructive... It was noted on analysis that the software had identified unusual prolonged events from the NP trace that did not correspond with any interruption to the regular thoraco-abdominal movement pattern, with no changes in SpO2... On closer examination these events were found to be the result of sudden and total cessation of nasal airflow... The NP trace showed that this patient was experiencing periods of complete nasal obstruction during the study, which appeared to correspond with the history during waking hours... Although mouth breathing has been demonstrated as occurring between 1 and 3% of recording time, usually causing a reduction in signal amplitude this patient׳s nasal obstruction episodes led the software to score numerous false positive events... Apart from the revision of the severity of OSA, there were no consequences for this patient as sleep-disordered breathing was identified, he was subsequently successfully treated with continuous positive airway pressure therapy, and his surgery went ahead as planned... However, the potential for false-positive results in the case of a less severe or a simple snoring patient is clear... Although it is known that NP signal may show a degree of decreased amplitude during mouth breathing, the onset of sudden and complete nasal obstruction during sleep is unique in our experience.

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Related in: MedlinePlus

Two 5-min sections from Somnologica software showing a period of complete nasal obstruction (marked by broken lines) preceded by genuine apnoea (A). Note normal RP and SpO2 during this period. A section of normal trace is shown from later in the study for comparison (B).
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f0005: Two 5-min sections from Somnologica software showing a period of complete nasal obstruction (marked by broken lines) preceded by genuine apnoea (A). Note normal RP and SpO2 during this period. A section of normal trace is shown from later in the study for comparison (B).

Mentions: It was noted on analysis that the software had identified unusual prolonged events from the NP trace that did not correspond with any interruption to the regular thoraco-abdominal movement pattern, with no changes in SpO2. On closer examination these events were found to be the result of sudden and total cessation of nasal airflow. Although some of these events were correctly marked as artefact, most lasting less than 120 s had been falsely identified as obstructive apnoea events. Normal NP traces were apparent both before and after each event. Following manual scoring by an experienced physiologist these events were eliminated from the final report; AHI was revised from 38 to 28 events per hour, thereby changing the category from severe to moderate Fig. 1.


Misleading sleep-diagnostic results in a patient with variable nasal airflow obstruction.

Spurling KJ, Perks JL, Makker HK - Sleep Sci (2015)

Two 5-min sections from Somnologica software showing a period of complete nasal obstruction (marked by broken lines) preceded by genuine apnoea (A). Note normal RP and SpO2 during this period. A section of normal trace is shown from later in the study for comparison (B).
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608887&req=5

f0005: Two 5-min sections from Somnologica software showing a period of complete nasal obstruction (marked by broken lines) preceded by genuine apnoea (A). Note normal RP and SpO2 during this period. A section of normal trace is shown from later in the study for comparison (B).
Mentions: It was noted on analysis that the software had identified unusual prolonged events from the NP trace that did not correspond with any interruption to the regular thoraco-abdominal movement pattern, with no changes in SpO2. On closer examination these events were found to be the result of sudden and total cessation of nasal airflow. Although some of these events were correctly marked as artefact, most lasting less than 120 s had been falsely identified as obstructive apnoea events. Normal NP traces were apparent both before and after each event. Following manual scoring by an experienced physiologist these events were eliminated from the final report; AHI was revised from 38 to 28 events per hour, thereby changing the category from severe to moderate Fig. 1.

View Article: PubMed Central - PubMed

Affiliation: Respiratory Physiology Department, North Middlesex University Hospital, London, UK.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

A 23 year old man was referred to our sleep clinic with a history of loud snoring, witnessed apnoeas and waking with a dry and sore throat... A Type III home sleep study was performed using Embletta Portable Diagnostic System (Stowood Scientific Instruments, Oxford UK) and Somnologica software (Embla, Broomfield, USA) for analysis, due to the comparability in diagnosing adult patients with a high probability of moderate to severe obstructive sleep apnoea... Initial results indicated severe obstructive sleep apnoea with an apnoea/hypopnoea index (AHI) of 38 events per hour, the majority of which were obstructive... It was noted on analysis that the software had identified unusual prolonged events from the NP trace that did not correspond with any interruption to the regular thoraco-abdominal movement pattern, with no changes in SpO2... On closer examination these events were found to be the result of sudden and total cessation of nasal airflow... The NP trace showed that this patient was experiencing periods of complete nasal obstruction during the study, which appeared to correspond with the history during waking hours... Although mouth breathing has been demonstrated as occurring between 1 and 3% of recording time, usually causing a reduction in signal amplitude this patient׳s nasal obstruction episodes led the software to score numerous false positive events... Apart from the revision of the severity of OSA, there were no consequences for this patient as sleep-disordered breathing was identified, he was subsequently successfully treated with continuous positive airway pressure therapy, and his surgery went ahead as planned... However, the potential for false-positive results in the case of a less severe or a simple snoring patient is clear... Although it is known that NP signal may show a degree of decreased amplitude during mouth breathing, the onset of sudden and complete nasal obstruction during sleep is unique in our experience.

No MeSH data available.


Related in: MedlinePlus