Proposal for a systematic analysis of polygraphy or polysomnography for identifying and scoring abnormal events occurring during non-invasive ventilation.

Non-invasive ventilation (NIV) is recognised as an effective treatment for chronic hypercapnic respiratory failure. Monitoring NIV during sleep may be preferable to daytime assessment. This paper reports the findings of an international consensus group which systematically analysed nocturnal polygraphic or polysomnographic tracings recorded with either volume-cycled or pressure-cycled ventilators. A systematic description of nocturnal respiratory events which occur during NIV is proposed: leaks, obstruction at different levels of the upper airway (glottis and/or pharynx), with or without decrease of respiratory drive and asynchrony.

The European Sleep Apnoea Database (ESADA): report from 22 European sleep laboratories.

The European Sleep Apnoea Database (ESADA) reflects a network of 22 sleep disorder centres in Europe enabled by a COST action B26 programme. This ongoing project aims to describe differences in standard clinical care of patients with obstructive sleep apnoea (OSA) and to establish a resource for genetic research in this disorder. Patients with suspected OSA are consecutively included and followed up according to local clinical standards. Anthropometrics, medical history, medication, daytime symptoms and sleep data (polysomnography or cardiorespiratory polygraphy) are recorded in a structured web-based report form. 5,103 patients (1,426 females, mean±sd age 51.8±12.6 yrs, 79.4% with apnoea/hypopnoea index (AHI) ≥5 events·h(-1)) were included from March 15, 2007 to August 1, 2009. Morbid obesity (body mass index ≥35 kg·m(-2)) was present in 21.1% of males and 28.6% of females. Cardiovascular, metabolic and pulmonary comorbidities were frequent (49.1%, 32.9% and 14.2%, respectively). Patients investigated with a polygraphic method had a lower AHI than those undergoing polysomnography (23.2±23.5 versus 29.1±26.3 events·h(-1), p<0.0001). The ESADA is a rapidly growing multicentre patient cohort that enables unique outcome research opportunities and genotyping. The first cross-sectional analysis reveals a high prevalence of cardiovascular and metabolic morbidity in patients investigated for OSA.

Medico-legal implications of sleep apnoea syndrome: driving license regulations in Europe.

BACKGROUND: Sleep apnoea syndrome (SAS), one of the main medical causes of excessive daytime sleepiness, has been shown to be a risk factor for traffic accidents. Treating SAS results in a normalized rate of traffic accidents. As part of the COST Action B-26, we looked at driving license regulations, and especially at its medical aspects in the European region. METHODS: We obtained data from Transport Authorities in 25 countries (Austria, AT; Belgium, BE; Czech Republic, CZ; Denmark, DK; Estonia, EE; Finland, FI; France, FR; Germany, DE; Greece, GR; Hungary, HU; Ireland, IE; Italy, IT; Lithuania, LT; Luxembourg, LU; Malta, MT; Netherlands, NL; Norway, EC; Poland, PL; Portugal, PT; Slovakia, SK; Slovenia, SI; Spain, ES; Sweden, SE; Switzerland, CH; United Kingdom, UK). RESULTS: Driving license regulations date from 1997 onwards. Excessive daytime sleepiness is mentioned in nine, whereas sleep apnoea syndrome is mentioned in 10 countries. A patient with untreated sleep apnoea is always considered unfit to drive. To recover the driving capacity, seven countries rely on a physician's medical certificate based on symptom control and compliance with therapy, whereas in two countries it is up to the patient to decide (on his doctor's advice) to drive again. Only FR requires a normalized electroencephalography (EEG)-based Maintenance of Wakefulness Test for professional drivers. Rare conditions (e.g., narcolepsy) are considered a driving safety risk more frequently than sleep apnoea syndrome. CONCLUSION: Despite the available scientific evidence, most countries in Europe do not include sleep apnoea syndrome or excessive daytime sleepiness among the specific medical conditions to be considered when judging whether or not a person is fit to drive. A unified European Directive seems desirable.

Comparison of lung deposition of amikacin by intrapulmonary percussive ventilation and jet nebulization by urinary monitoring.

The intrapulmonary percussive ventilation (IPV), frequently coupled with a nebulizer, is increasingly used as a physiotherapy technique; however, its physiologic and clinical values have been poorly studied. The aim of this study was to compare lung deposition of amikacin by the nebulizer of the IPV device (Percussionaire; Percussionaire Corporation; Sandpoint, ID) and that of standard jet nebulization (SST; SideStream; Medic-Aid; West Sussex, UK). Amikacin was nebulized with both devices in a group of five healthy subjects during spontaneous breathing. The deposition of amikacin was measured by urinary monitoring. Drug output of both devices was measured. Respiratory frequency (RF) was significantly lower when comparing the IPV device with SST (8.2 +/- 1.6 breaths/min vs. 12.6 +/- 2.5 breaths/min, p < 0.05). The total daily amount of amikacin excreted in the urine was significantly lower with IPV than with SST (0.8% initial dose vs. 5.6% initial dose, p < 0.001). Elimination halflife was identical with both devices. Drug output was lower with IPV than with SST. The amount of amikacin delivered to the lung is sixfold lower with IPV than with SST, although a lower respiratory frequency was adopted by the subjects with the IPV. Therefore, the IPV seems unfavorable for the nebulization of antibiotics.

Failure of tonsil and nose surgery in adults with long-standing severe sleep apnea syndrome.

Seven adult patients with a severe form of sleep apnea syndrome (mean apnea index, 47) underwent surgery for significant structural abnormalities at nose and/or throat level (septal deviation, turbinal hypertrophy, enlarged tonsils, long uvula, pharyngeal tumor). Although a subjective benefit was claimed by most patients, the polygraphic data showed no improvement or only a modest improvement in breathing pattern, oxyhemoglobin saturation, or general sleep architecture except in one patient. In this patient the evolution of the syndrome was recent (3 years) and surgical management of a parapharyngeal tumor resulted in a cure. We conclude that in adults with sleep apnea syndrome of long-standing, surgical correction of nasal or pharyngeal abnormalities should not be expected to normalize sleep and breathing. This contrasts with the known benefits achieved by the same type of surgery in children. Surgery might nevertheless be necessary in some adults to permit the application of other therapeutic means (ie, nasal continuous positive airway pressure).

Nasal obstruction and its impact on sleep-related breathing disorders.

Upper airway patency is essential during sleep in order to avoid sleep-related breathing disorders (SRBD). Nasal obstruction may have a negative impact on sleep quality and must be considered to be a co-factor in the pathophysiology of SRBD. In this paper we will discuss the relation between nasal physiology at night and sleep quality and the possible mechanisms between nasal obstruction and obstructive sleep apnea-hypopnea syndrome (OSAS). We will review the effect of the relief of nasal obstruction (with nasal dilators, medication and/or surgery) on SRBD. Also an algorithm on the management of OSAS patients when nasal surgery is indicated will be proposed.

Pharmacokinetics of oral acetylcysteine: absorption, binding and metabolism in patients with respiratory disorders.

The fate of an oral 100 mg dose of 35S-acetylcysteine, a mucolytic agent, was studied in 10 patients with respiratory disorders, 5 of whom underwent pneumonectomy or lobectomy a few hours after administration of the drug. In the 5 nonoperated patients, plasma radioactivity concentrations were maximal after 2 to 3 hours and remained high after 24 hours; about 22% of radioactivity was excreted in urine after 24 hours. In the 5 operated patients, plasma radioactivity concentrations were comparable with those in the nonoperated patients. Lung tissue radioactivity concentrations after 5 hours were comparable with those in plasma, while the presence of small amounts of radioactivity in the bronchial secretions indicates that acetylcysteine passes into the mucus. Total radioactivity after 5 hours consisted of free, unchanged drug and metabolites (about 22% of total in plasma, 48% in lung tissue), unchanged drug bound to protein by means of labile disulphide bridges (about 14% in plasma, 47% in lung tissue), and drug firmly bound to protein (about 64% in plasma, 5% in lung tissue). Oral acetylcysteine is rapidly absorbed and slowly excreted and is available in the lung in an active form for at least 5 hours at high concentrations.

Assessment of uvulopalatopharyngoplasty for the treatment of sleep apnea syndrome.

Uvulopalatopharyngoplasty (UPPP) consists in the surgical removal of the uvula, part of the muscular portion of the soft palate and redundant palatal and pillar mucosa, and the tonsils. Since 1981, UPPP has been proposed for the treatment of sleep apnea syndrome. Polysomnographic studies have shown that in about half of the patients submitted to UPPP there is a 50% or greater reduction in apnea index. Attempts to identify presurgically those patients more likely to benefit from UPPP have yielded inconsistent results. Limited retrospective follow-up data suggest that UPPP does not modify the increased mortality associated with moderate and severe sleep apnea syndrome. Patients submitted to UPPP report subjective improvement, irrespective of the objective polysomnographic postsurgical results. It is suggested that polysomnographic evaluation of UPPP results should be mandatory; that any patient with 20 or more apnea/hypopneas per hour of sleep or sleep fragmentation after UPPP should be considered a treatment failure and be offered alternative therapy; and that UPPP should be performed only as part of prospective clinical trials including long-term follow-up.

Cure of sleep apnea syndrome after long-term nasal continuous positive airway pressure therapy and weight loss.

Two male patients [aged 53 and 54 years; body mass index (BMI) of 36.8 and 34.4 kg/m2] presented with severely symptomatic sleep apnea syndrome. Polysomnographic recording showed sleep fragmentation, diminution of stages III and IV and continuous sleep-related disordered breathing with mixed and obstructive apneas and hypopneas, and snoring. Apnea index (number of apneas per sleep-hour) was 73 and 30, respectively. These abnormalities were reversed by nasal continuous positive airway pressure (nCPAP). Home treatment with nCPAP associated with hypocaloric diet was started. Six months later, all symptoms had disappeared and BMI was 29 and 29.2 kg/m2, respectively. Polygraphic recordings without nCPAP showed regular breathing in all sleep stages, which were stable and normally abundant. Therapy has been discontinued and clinical and polygraphic data have remained normal for up to 6 and 11 months, respectively.

Why should we enlarge the pharynx in obstructive sleep apnea?

Patency of the collapsible segment of the pharynx is dependent upon the interplay of anatomic and physiologic factors. The upper airway of the typical patient with obstructive sleep apnea (OSA) is structurally narrowed by fat deposits in the lateral pharyngeal walls. During wakefulness, the upper airway dilator muscles compensate for the structurally reduced pharyngeal size by increasing their activity, thereby pulling the tongue and soft palate forward. As a consequence, the cross-sectional area is relatively preserved, but the shape of the pharynx becomes elliptical along the anteroposterior axis. In the awake patient with OSA, patency of the pharynx is largely dependent upon increased dilator muscle activity. During sleep, the activity of the muscular apparatus of the pharynx decreases causing a critical narrowing. Because anatomic narrowing appears to be a basic feature, enlarging the pharynx should be beneficial, particularly if its lateral diameter can be increased. Whereas facial advancement surgery structurally increases the anteroposterior diameter of the pharynx, thereby accounting for the good results reported with this technique, it is doubtful that uvulopalatopharyngoplasty has a similar effect on either the anter-oposterior or lateral diameters of the pharynx.

Pattern of snoring in obstructive sleep apnea patients and in heavy snorers.

We measured respiratory mechanical characteristics during sleep in five heavy, nonapneic snorers (HS) and in five obstructive sleep apnea (OSA) patients. In two HS and in two OSA patients we obtained lateral pharyngeal cineradiographic images during sleep while snoring. Flow limitation preceded all snores in both HS and OSA. Pattern of snoring, hysteresis and temporal relationship between supraglottic pressure (Psg) and flow rate were different in HS and OSA. Maximal flow during snoring was less (p less than 0.05) in OSA (0.18 +/- 0.07 liter/second) than in HS (0.36 +/- 0.06 liter/second). Linear supraglottic resistance during inspiratory snoring was higher, though not significantly, in OSA patients (7.11 +/- 3.01 cm H2O/liter/second) than in HS (4.80 +/- 2.83 cm H2O/liter/second). We conclude that: 1) Snoring is characterized by high frequency oscillations of the soft palate, pharyngeal walls, epiglottis and tongue. 2) Flow limitation appears to be a sine qua non for snoring during sleep. 3) The pattern of snoring is different in OSA and HS. 4) Pharyngeal size during snoring is probably larger in HS than in OSA patients.

Weight loss as a treatment for obstructive sleep apnoea.

Obesity is a major health problem in well-developed societies. It is frequently associated with metabolic, cardiovascular and psychological comorbid conditions. Besides, it is known that obesity constitutes a risk factor for obstructive sleep apnoea (OSA). Weight loss has been evaluated as a treatment for OSA. We reviewed the nature of the link between obesity and OSA as well as the conservative and surgical therapeutic approaches of obesity. We consider the effectiveness of weight loss alone or combined with other modalities of treatment in OSA. We conclude that although weight loss is important and can facilitate the treatment of OSA, it can rarely cure it without being associated to classical techniques, such as nasal continuous positive airway pressure (nCPAP).

Compliance with nasal CPAP in obstructive sleep apnea patients.

Continuous positive airway pressure (CPAP) is currently the treatment of choice for the majority of patients with obstructive sleep apnea (OSA). After a CPAP trial, the initial acceptance rate is 70-80%. Patients who derive no subjective benefit from such a trial are poor candidates for home treatment with CPAP because they are likely to exhibit lower adherence and compliance rates. About 90% of OSA patients provided with CPAP apparatus will adhere to long-term CPAP treatment. Patients abandoning CPAP do so during the first few months of home therapy, a period during which close monitoring and support is warranted. Because of the strong correlation between the machine run time and effective pressure delivered at the nasal mask (90-95%), the time-counter of the CPAP device is sufficient to monitor compliance in clinical practice, allowing for early intervention in cases of suboptimal use. Longterm acceptors of CPAP display a satisfactory compliance (5-6.5 h of average daily use) which compares favourably with compliance with treatment in other chronic diseases. Lower acceptance and compliance rates have been reported in North America as compared to Europe. This could be related to cultural differences or different routines of prescription and follow-up.

Nasal continuous positive airway pressure in the perioperative management of patients with obstructive sleep apnea submitted to surgery.

Anesthetic, sedative, and analgesic drugs have been shown in animals and humans to selectively impair upper airway muscle activity. In patients with an already compromised upper airway, these drugs may further jeopardize upper airway patency, especially during sleep. Thus, patients with obstructive sleep apnea syndrome (OSAS) are at high risk for surgery because of the use of the aforementioned drugs in the perioperative period. It has been recommended that such drugs should be avoided or used with extreme caution in patients with OSAS submitted to surgery. We report herein on 16 adult patients with documented OSAS undergoing various types of surgical procedures, including coronary artery bypass surgery. Anesthesia was carried on with the usual type of drugs for each type of surgery. Postoperative opioid analgesia and sedation were not restricted. The first patient, whose OSAS was diagnosed but not treated, died after various complications, including a respiratory arrest in the ward. The second patient experienced serious postoperative complications until a treatment for OSAS with nasal continuous positive airway pressure (N-CPAP) was instituted, and thereafter he made an uneventful recovery. The 14 following patients were started on N-CPAP before surgery, were put on N-CPAP as soon as extubated, on a near-continuous basis, for 24 to 48 h and thereafter for all sleep periods. None of them had major complications. The intensive care unit and hospital stays were the normal ones for each type of surgery in our institution. We conclude that N-CPAP started before surgery and resumed immediately after extubation allowed us to safely manage a variety of surgical procedures in patients with OSAS, and to freely use sedative, analgesic, and anesthetic drugs without major complications. Every effort should be made to identify patients with OSAS and institute N-CPAP therapy before surgery.

The single-breath diffusing capacity for carbon monoxide in obstructive sleep apnea and obesity.

BACKGROUND: We have observed high values of single-breath diffusing capacity for carbon monoxide (Dco) in patients with obstructive sleep apnea (OSA). STUDY OBJECTIVES: To confirm this observation and to determine the factors influencing diffusion indices in patients with OSA. As weight excess was found to be the major determinant of increased diffusion indices, the adequacy of various prediction equations was evaluate in obese subjects. DESIGN: Retrospective data collection. SETTING: University hospital. METHODS: DCO was measured in patients with OSA and in nonapneic subjects who served as control SUBJECTS: The results were expressed with respect to our own reference values and also to other prediction equations. RESULTS: In moderate/severe OSA (apnea/hypopnea index [AHI] > or = 30), both DCO and transfer coefficient (KCO) were increased and KCO was positively correlated with AHI and body mass index (BMI). Diffusion indices were not different between patients with moderate/severe OSA and nonapneic control subjects matched for age and BMI. In the latter group, KCO was also correlated with BMI. In our obese patients (BMI, 36.7 +/- 5.6 kg/m2), DCO was about 10% and KCO was 20 to 25% greater than predicted by standard reference equations. CONCLUSIONS: DCO and KCO are increased in a typical population of patients with moderate/severe OSA. This appears to be due to weight excess and not to OSA itself. In obese subjects, whether apneic or not, BMI is a determinant of diffusion indices that are higher than predicted by equations relying on age and stature alone.

Spontaneous favorable outcome of tracheal laceration.

We present the case of a 57-year-old woman with a huge tracheal laceration after intubation. With simple supportive therapy, the laceration healed in ten days, and the patient made an uneventful recovery. At the three-month follow-up, no sequelae were observed.