Occult sleep apnea: the dilemma of negative polysomnography in symptomatic patients

doi:10.1016/j.sleep.2004.05.005

Sleep Medicine

Volume 5, Issue 5, September 2004, Pages 501-506

https://doi.org/10.1016/j.sleep.2004.05.005 Get rights and content

Abstract

Background and purpose

To determine the benefit of repeat polysomnography with/without esophageal pressure (PES) monitoring to diagnose sleep apnea syndrome (SAS) in patients with symptoms of sleep apnea who have had a ‘negative’, single-night polysomnogram (PSG).

Patients and methods

This is a retrospective investigation of 1187 patients seen in our sleep lab from January to December 2001, of which 709 were adults suspected of having sleep apnea. Following a single PSG, 588 patients were diagnosed with sleep apnea and 121 had negative PSGs (an apnea–hypopnea index <5 events per hour). Of the 121 patients, 92 continued to complain of unexplained sleepiness, loud snoring, or apnea, symptoms which were also documented on their initial evaluation (PSG or multiple sleep latency testing). The remaining 29 patients had no further complaints, or another medical cause of their sleepiness was established (i.e. asthma) following the single-night PSG. Of the 92 patients, 28 underwent additional screening with both repeat PSG and PES monitoring within the following 6 months.

Results

With repeat PSG and PES monitoring, 18 of the 28 patients with previous, negative PSGs were diagnosed with sleep apnea. The sensitivity of a single-night PSG fell to 97%, with a false negative rate of 3%. Only 12 of the 28 would have been positive based on polysomnographic criteria alone, without the additional PES monitoring. On the other hand, 10 of the 28 remained negative and further evaluation revealed other, underlying medical problems (i.e. nocturnal asthma) that explained their symptoms.

Conclusions

There is a clear benefit of repeat PSG, with or without PES monitoring, for patients with a prior negative PSG and continued symptoms suspected of having SAS.

Introduction

Patients, in general, will not seek medical attention unless they are prompted by a bothersome symptom. In the case of sleep apnea, it is usually snoring, witnessed apnea, or excessive daytime somnolence (EDS). It is the task of the sleep physician and laboratory to identify patients with sleep apnea and to initiate therapy. The current practice standard is predicated on one-night polysomnography. If it is negative (apnea–hypopnea index (AHI) <5 events per hour), the diagnosis of sleep apnea is usually discarded. However, a significant group of these patients remain symptomatic despite negative testing. If the clinical suspicion for obstructive sleep apnea (OSA) exists, and polysomnography is negative, the physician faces a true dilemma with regards to further patient management. Untreated, sleep apnea may lead to an increased risk of hypertension, stroke, myocardial infarction and even death (1). Patient complaints should not be dismissed, especially after effective treatment for sleep apnea that may alter associated cardiovascular outcomes and the effects of excessive daytime tiredness on the patient's quality of life.

The variability with which sleep apnea occurs on a night-to-night basis has been suggested (2), but its clinical significance has not yet been fully elucidated. When patients are tested in the laboratory, they do not always meet the diagnostic threshold for OSA (AHI >5 events per hour) with one night of polysomnography. Regardless of this, it is clearly recognized that increased nocturnal respiratory effort subsequently leads to EDS. The purpose of our study was to evaluate patients with symptoms of sleep apnea who had a negative polysomnogram (PSG) and no other diagnosis to explain their symptoms.

Section snippets

Selection criteria

Following Institutional Review Board approval, 1187 PSG studies performed at the Sleep-Wake Center at Hackensack University Medical Center from January to December 2001 were reviewed retrospectively. Informed consent for PSG was obtained. Of the 1187 patients initially identified, 478 were excluded from analysis (due to a previously established diagnosis, or age <18 years) and 709 remained.

Patients were not excluded on the basis of race, sex, body mass index (BMI), or comorbidities (Fig. 1). To

Results

Of 709 patients who underwent PSG for suspected sleep apnea (Fig. 1), 588 were diagnosed with sleep apnea with a single-night PSG and 121 had a negative initial study. Of these, 29 had their sleepiness readily explained by a condition other than sleep apnea (i.e. narcolepsy, congestive heart failure, nocturnal asthma, etc.). Ninety-two patients continued to have unexplained symptoms.

Of these 92, 64 declined further evaluation and 28 underwent repeat PSG with PES monitoring. There was no

Discussion

OSA is a clinical diagnosis, confirmed by polysomnography. Only 83% of our patients (588/709) with clinically suspected OSA were diagnosed by single-night PSG. The main focus of our study was to determine whether further evaluation with repeat PSG and PES monitoring would reveal additional cases of OSA. PSG diagnosis (as opposed to clinical criteria alone) is beneficial in confirming the diagnosis of OSA while excluding other causes of sleepiness, and also enables patients to seek reimbursement

Acknowledgements

Special thanks to all members of our Sleep Laboratory, especially Dr Susan Zafarlotfi, Lauren Dempsey and Randy Tasker.

References (24)

C. Guilleminault et al.
A cause of excessive daytime sleepiness: the upper airway resistance syndrome
Chest
(1993)
O. Le Bon et al.
Mild to moderate sleep respiratory events: one negative night may not be enough
Chest
(2000)
C. Guilleminault et al.
Arousal and upper airway resistance
Sleep Med
(2002)
J.R. Wheatley
Definition and diagnosis of upper airway resistance syndrome
Sleep
(2000)
Chesson AL, Ferber RA, Fry JM, et al. The indications for polysomnography and related procedures. An American Sleep...
Center for Medicare and Medicaid Services. #CAG-00093R. Continuous positive airway pressure, 60-17;...
Medtronics Minneapolis, MN. Clinical application of air pressure measurements;...
Rechtschaffen A, Kales A. A manual of standardized terminology, techniques and scoring system for sleep stages of human...
C. Cracowski et al.
Characterization of obstructive nonapneic respiratory events in moderate sleep apnea syndrome
Am J Respir Crit Care Med
(2001)
Standardized Scoring Of Sleep Studies
AASM
Sleep
(1999)

R.D. Chervin et al.

Effects of esophageal pressure monitoring on sleep architecture

Am J Respir Crit Care Med

(1997)

O. Skatvedt et al.

Nocturnal polysomnography with and without continuous pharyngeal and esophageal pressure measurements

Sleep

(1996)

Cited by (8)

Assessment of respiratory effort during sleep: Esophageal pressure versus noninvasive monitoring techniques
2015, Sleep Medicine Reviews
Citation Excerpt :
Guilleminault and Chowdhuri have empirically identified three other Pes-associated respiratory patterns that are associated with arousals: a) increased Pes, without crescendo, terminated by a Pes reversal; b) one or two breath increases in Pes preceding a Pes reversal; and c) tachypnea with normal Pes, abruptly terminated by a normal breath [22]. Many other Pes-associated patterns have been described in the literature and have been used to define respiratory events [14,23–34] (Table 1). Obviously, there is no uniform definition of Pes events and it may be anticipated that different types exist in different patient populations [35].
Monitoring of respiratory effort is paramount in the clinical diagnostic recording of sleep. Increased respiratory effort is a sign of obstructive sleep-disordered breathing and is associated with arousals from sleep. Respiration is the result of muscle activity that induces negative intrathoracic pressure and expansion of the thoracic and abdominal cavities. Therefore respiratory effort may be recorded from mechanical, electrical and electromechanical signals. Several techniques are available for the recording of respiratory effort. Monitoring of esophageal pressure is still the method of choice, as the pressure signal directly reflects the respiratory muscle force. However, esophageal pressure monitoring is cumbersome and may be replaced with noninvasive techniques. In order to be reliable, these techniques must be validated against the esophageal pressure standard. The present review presents a concise description of the technical principles and, if available, a comparison with esophageal pressure data, based on a systematic literature search. Most data are available on respiratory inductance plethysmography, and confirm that this technique is suitable for routine diagnostic investigation of respiratory effort during sleep. Pulse transit time, diaphragmatic electromyography, snoring loudness, suprasternal pressure monitoring, midsagittal jaw movement and forehead venous pressure monitoring are promising alternative techniques although only limited validation is available.
Polysomnography with an epiglottic pressure catheter does not alter obstructive sleep apnea severity or sleep efficiency
2019, Journal of Sleep Research
Night-to-night variability in sleep disordered breathing and the utility of esophageal pressure monitoring in suspected obstructive sleep apnea
2015, Journal of Clinical Sleep Medicine
Sleep bruxism and sleep-disordered breathing: A systematic review
2014, Journal of Oral and Facial Pain and Headache
How should a commercial driver medical examiner approach determining fitness for duty in a commercial motor vehicle operator with a body mass index ≥ 33 kg/m<sup>2</sup>?
2012, Journal of Occupational and Environmental Medicine
Association of sleep apnea with coronary slow-flow phenomenon
2012, Journal of Cardiovascular Medicine

View all citing articles on Scopus

View full text

Original articleOccult sleep apnea: the dilemma of negative polysomnography in symptomatic patients

Abstract

Background and purpose

Patients and methods

Results

Conclusions

Introduction

Section snippets

Selection criteria

Results

Discussion

Acknowledgements

Chest

Chest

Sleep Med

Definition and diagnosis of upper airway resistance syndrome

Sleep

Characterization of obstructive nonapneic respiratory events in moderate sleep apnea syndrome

Am J Respir Crit Care Med

AASM

Sleep

Effects of esophageal pressure monitoring on sleep architecture

Am J Respir Crit Care Med

Nocturnal polysomnography with and without continuous pharyngeal and esophageal pressure measurements

Sleep

Original article
Occult sleep apnea: the dilemma of negative polysomnography in symptomatic patients