Management of obstructive sleep apnea in Europe.

OBJECTIVES: In Europe, the services provided for the investigation and management of obstructive sleep apnoea (OSA) varies from country to country. The aim of this questionnaire-based study was to investigate the current status of diagnostic pathways and therapeutic approaches applied in the treatment of OSA in Europe, qualification requirements of physicians involved in diagnosis and treatment of OSA, and reimbursement of these services. METHODS: Two questionnaires were sent to 39 physicians in 22 countries in Europe. In order to standardize the responses, the questionnaire was accompanied by an example. RESULTS: Sleep centers from 21 countries (38 physicians) participated. A broad consistency among countries with respect to the following was found: pathways included referral to sleep physicians/sleep laboratories, necessity for objective diagnosis (primarily by polysomnography), use of polygraphic methods, analysis of polysomnography (PSG), indications for positive airway pressure (PAP) therapy, application of standard continuous PAP (CPAP) therapy (100% with an CPAP/APAP ratio of 2.24:1), and the need (90.5%) and management of follow-up. Differences were apparent in reimbursement of the diagnostic procedures and follow-up, in the procedures for PAP titration from home APAP titration with portable sleep apnea monitoring (38.1%) up to hospital monitoring with PSG and APAP (85.7%), and in the qualification requirements of sleep physicians. CONCLUSIONS: Management of OSA in different European countries is similar except for reimbursement rules, qualification of sleep specialists and procedures for titration of the CPAP treatment. A European network (such as the one accomplished by the European Cooperation in Science and Technology [COST] B26 Action) could be helpful for implementing these findings into health-service research in order to standardize management in a cost effective perspective.

Proinflammatory cytokines Il-6 and TNF-α and the development of inflammation in obese subjects.

BACKGROUND: The development of obesity and related disorders, e.g., type II diabetes (T2D), hypertension, and metabolic disturbances is strongly related to increased levels in proinflammatory cytokines (IL-1, IL-6, and TNF-α). Both IL-6 and TNF-α are secreted by adipocytes and their concentration correlates with the percentage and distribution of fat tissue in the body. Both cytokines are the main factors responsible for the induction of acute phase proteins production (e.g., CRP) and to inflammatory state. OBJECTIVE: To compare of TNF-α and IL-6 concentrations in serum from obese subjects with those in subjects with normal BMI and to analyze the relation between TNF-α, IL-6, BMI and the inflammatory state as measured by the level of CRP. MATERIAL AND METHODS: The study included 80 obese subject (54 males and 26 females) BMI >25 kg/m⊃2. A control group consisted of 53 healthy subjects (24 males and 29 females) with BMI <25 kg/m⊃2. To determine the blood plasma concentration of IL-6 and TNF, commercial ELISA assay kits were used. RESULTS: The concentration of IL-6 was lower in the control compared with the obese patients, but a significance difference concerned only female subjects (P = 0.001). TNF-α concentration was significantly higher in all obese subjects (P<0.001). A higher level of this cytokine was also found in patients with obesity suffering from T2DM. A positive correlation was present between IL-6 and TNF-α concentrations. Only did the IL-6 level correlate with the concentration of CRP in serum. CONCLUSIONS: The study confirmed that increased inflammatory cytokines lead to the persistence of inflammation in obese subjects. However, some other factors, such as gender, may contribute to the development of obesity-related inflammatory states.

Frequency of distribution of inflammatory cytokines IL-1, IL-6 and TNF-alpha gene polymorphism in patients with obstructive sleep apnea.

Obesity is one of the most commonly identified factors for the obstructive sleep apnea syndrome (OSAS). Adipose tissue is the source of many cytokines, among them there are IL-6, IL-1, and TNF-alpha. The level of inflammatory cytokines increases in people with OSAS and obesity. The aim of this study was to evaluate the distribution of genotypes in inflammatory cytokine genes in people with obesity-related OSAS. The examined group consisted of 102 person with obesity related-OSAS and 77 normal weight person without OSAS. Genotyping of DNA sequence variation was carried out by restriction enzyme (IL-1: Taq I, IL-6: Lwe I, TNF-alpha: Nco I) analysis of PCR amplified DNA. The study revealed a significant correlation between polymorphism located in the promoter region of inflammatory cytokine genes and obesity-related OSAS.

Frequency of distribution of leptin receptor gene polymorphism in obstructive sleep apnea patients.

Leptin is an adipocyte-derived hormone regulating energy homeostasis and body weight. Leptin concentration is increased in patients with the obstructive sleep apnea syndrome (OSAS). Leptin receptor (LEPR) is a single transmembrane protein belonging to the superfamily of cytokine receptors related by a structure to the hemopoietin receptor family. The aim of the present study was to evaluate the frequency of distribution of leptin receptor gene polymorphism GLN223ARG in OSAS patients compared with healthy controls. The examined group included 179 subjects: 102 OSAS patients (74 men and 28 women) and 77 non-apneic controls (39 men and 38 women). Genomic DNA was isolated with the use of a column method and genotyping of DNA sequence variation was carried out by restriction enzyme analysis of PCR-amplified DNA. The results revealed a significant correlation between the polymorphism of LEPR and OSAS. Carriers of Arg allele in homozygotic genotype Arg/Arg and heterozygotic genotype Gln/Arg were more often obese and developed OSAS than the group of carriers of homozygotic Gln/Gln genotype. This tendency was observed in the whole examined population and in the group of obese women. We also found the highest levels of total cholesterol, LDL, HDL, and triglycerides in the group of homozygotic Arg/Arg genotype carriers, lower in heterozygotic Gln/Arg genotype carriers, and the lowest in the group of persons carring homozygotic Gln/Gln genotype. The presence of Arg allel seems linked to a higher risk of obesity and higher lipid levels in OSAS patients. OSAS may have a strong genetic basis due to the effects from a variety of genes including those for leptin receptor.

Leptin measurement in urine is a reliable method of monitoring its secretion in patients with obstructive sleep apnea syndrome.

Leptin is believed to play a significant role in the pathogenesis of obstructive sleep apnea syndrome (OSAS) as well as progression of OSAS-related obesity. It is also known that other factors such as gender and diurnal variations in serum strongly affect the measurement results making repeated blood sampling necessary for leptin precise monitoring. Since renal metabolism and urine secretion are the main elimination mechanism for leptin, in this study we evaluated urine relevance for leptin secretion monitoring. Serum and urine (collected during the day and overnight) sampled from 169 OSAS patients and 41 controls were assayed by immunoenzymatic method specific for human leptin. Only 5 (17%) controls and 10 (5.8%) OSAS patients had undetectable urine leptin. We observed significant relationships between serum and urinary leptin in both day-time (r=0.656, P<0.001) and night-time (r=0.518, P<0.001) samples and between day and night-time urine leptin (r=0.811, P<0.001). Significance values did not alter when urinary leptin levels were expressed as the ratio to urinary creatinine. Gender-related differences in leptin concentrations were present both in serum (P<0.001) and overnight urine (P<0.01) in the OSAS group. However, mean night-time urine leptin was lower in the OSAS patients (P<0.05) and their subgroups stratified according to disease severity (P<0.01), while serum leptin levels were comparable in both groups. We conclude that assaying leptin in urine by immunoenzymatic method is a reliable and useful non-invasive alternative for its serum measurement. However, night-time urine leptin levels better reflect differences in its turnover due to gender and OSAS severity.

Disturbed angiogenic activity in sera from obstructive sleep apnea patients.

It is increasingly recognized that obstructive sleep apnea (OSA) syndrome is a systematic rather than local disorder. There is also growing evidence that apart from the syndrome's major features: intermittent hypoxia and sleep fragmentation, functional activity of the immune system is altered in OSA patients, with several cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) taking active part in sleep regulation. Little is known about the effects exerted by chronic intermittent hypoxia combined with persistent pro-inflammatory activity of the immune system on the vascular micro milieu in OSA. In this study we attempted to confirm the hypothesized imbalance between pro- and anti-angiogenic factors by evaluating direct and indirect angiogenic activity of OSA patients' sera in the in vivo serum-induced angiogenesis (SIA) and leukocyte-induced (LIA) assays, respectively, in mice. Both tests revealed significantly inhibited angiogenic activity of OSA patients' sera compared with healthy controls (P<0.001). Moreover, differences related to the subject's weight regarding in the mean number of newly-formed vessels were observed with a significantly greater inhibition in the normal-weighing apneic subjects than in the overweight or obese ones (P<0.01). The angiogenesis inhibition index was positively related to the serum IL-6 level (r=0.35; P<0.05) in the OSA group, but not to TNF-alpha, fasting serum leptin, or OSA syndrome severity as assessed by the AHI index. Our results demonstrate that OSA is accompanied by disturbed serum angiogenic activity, apparently resulting from an imbalance between pro- and anti-angiogenic factors, some of them being produced by the adipose tissue. The disordered angiogenic activity might be related to the pathophysiology of OSA and should be considered an important causative factor for the increased prevalence of cardiovascular diseases in OSA patients.

Pulmonary haemodynamics in patients with OSAS or an overlap syndrome.

BACKGROUND: Alveolar hypoxia is the most important mechanism leading to pulmonary arterial vasoconstriction, remodelling and pulmonary hypertension. Patients with Obstructive Sleep Apnoea Syndrome (OSAS) experience multiple short periods of alveolar hypoxia during apnoeic episodes. However, the question as to whether these hypoxic episodes are responsible for the development of permanent pulmonary hypertension is still debatable. We aimed to investigate the relationship between the episodes of nocturnal desaturation and pulmonary haemodynamics in two distinct group patients: with pure OSAS or an overlap syndrome. METHODS: We studied 67 patients with severe OSAS (means: age 45+/-8 years, AHI 62+/-22, FEV1 3.6+/-0.8 L = 97+/-16% of predicted PaO2 72+/-10 mmHg, PaCO2 40+/-4 mmHg) and 17 patients with an overlap syndrome (OS), means: age 51+/-5 years, AHI 64+/-19, FEV1 1.5+/-0.7 = 43+/-16% of predicted PaO2 57+/-9 mmHg). All subjects underwent pulmonary artery catheterisation with pressure and flow recordings and an overnight full sleep study. RESULTS: On average patients with OSAS had nocturnal desaturation (mean overnight SaO2 = 87+/-5%) and normal PPA (15.8+/-4.6 mmHg). Only 11 out of 67 subjects (16%) presented with pulmonary hypertension. Patients with OS had nocturnal desaturation (mean overnight SaO2 = 80.2+/-8.5%) and mild pulmonary hypertension (PPA 24.2+/-7.4 mmHg). Only three out of 17 patients had normal pulmonary arterial pressure. CONCLUSIONS: In patients with severe OSAS, pulmonary hypertension is rare (16%) and is related best to the severity of the disease and to obesity. In OS patients diurnal pulmonary hypertension is frequent but does not correlate with the severity of nocturnal desaturation.

[Snoring and excessive daytime somnolence and risk of cardiovascular diseases]. / Chrapanie i nadmierna sennosc dzienna a ryzyko chorób sercowo-naczyniowych.

Snoring and excessive daytime somnolence (EDS) are very common in middle-age adults. The goal of the investigation was to assess links between those symptoms and risk for cardiovascular diseases (CVD). The population studied included 1186 inhabitants of Warsaw (mean age 52 years), participants of the international multicentre study of cardiovascular disease MONICA II, who completed the sleep disordered breathing (SDB) questionnaire. Snoring was reported by 78% of males (48% habitual and 30% occasional) and 59% of females (27% habitual and 32% occasional). Every fourth (26.8%) subject declared observed apnoeas, in 9.2% apnoeas were observed every night. EDS was declared by 28.7% of studied sample. The results of the questionnaire were compared to the results of MONICA study. Snorers had significantly higher systolic and diastolic blood pressure (133.2 +/- 23/84.6 +/- 13 mm Hg) compared to non-snorers (126.4 +/- 22/80.4 +/- +/- 12 mm Hg) (p < 0.0001). The high total serum cholesterol (> or = 200 mg%) and triglycerides (> or = 200 mg%) concentration, and also obesity (BMI > or = 30 kg/m2) were more prevalent in snorers. Subjects reporting apnoeas more often had coronary artery disease (p < 0.001) or history of stroke (p = 0.002) compared to non-apnoeics. There was no relationship between EDS and risk of cardiovascular disorders, and also between diabetes and SDB. In conclusion, snoring was strongly associated with hyperlipidaemia, obesity or hypertension, well known risk factors for development of cardiovascular disorders. Reported apnoeas were related to risk of coronary artery disease.

[Clinical value of polymesam recording in diagnosis of obstructive sleep apnea. Can we replace polysomnography with polymesam?]. / Ocena kliniczna ograniczonego badania aparatem Polymesam w rozpoznawaniu obturacy jnego bezdechu sennego. Czy polisomnografie mozna zastapic badaniem polymesam?

UNLABELLED: Polymesam (PM) recordings was performed in 320 patients admitted to Sleep Laboratory with suspicion of OSA. OSA was diagnosed in 179 of them (55.9%), group (PM-Ch). These patients were obese (BMI--34.3 +/- 6.7 kg/m2) and had moderately-severe OSA (RDI--41.5 +/- 19.9 and ODI--43.7 +/- 21.5). They suffered from excessive daytime sleepiness (ESS = 12.2 +/- 5.5). PM was negative in 141 person (44.1%), (PM-Z). Subjects PM-Z had significantly lower BMI and rarely suffered from excessive daytime sleepiness. In 38 subjects PM-Z a full PSG was performed. In 12 PSG confirmed OSA (AHI--31.6 +/- 19.9). Both studies (PM and PSG) were negative in 26 subjects. In 10 obese subjects PM-Ch full PSG confirmed diagnosis. CONCLUSIONS: PM recording can replace full PSG in majority of patients suspected of OSA. Patients with typical symptoms of OSA and negative PM require PSG.

[Ten years experience of the sleep laboratory at the Institute of Tuberculosis and Lung Disease in Warsaw]. / Dziesiec lat doswiadczen pracowni zaburzen oddychania w czasie snu w Instytucie Gruzlicy i Chorób pluc.

Between 1991-2000 2052 patients (81% men and 19% women) were referred to our Sleep Laboratory because of OSA suspision. In 1194 (58%) subjects (88% men and 12% women) diagnosis of obstructive sleep apnoea (OSA, AHI > 10) was confirmed. In 430 of them (36%) mild OSA (AHI 11-25), in 243 (20%) moderate OSA (AHI 26-40), and in 521 (44%) severe OSA (AHI > 40) was diagnosed. Epworth sleepiness scale score in those groups was 10.4, 10.5 and 13.0 points respectively. 908 (76%) of patients with OSA were submitted to nCPAP treatment. Effective CPAP pressure ranged from 5 to 20 milibars, mean 8.4 mbars. In 21 patients upper airway resistance syndrome (UARS) was diagnosed. Central sleep apnoea, most frequently of Cheyne-Stokes respiration type was diagnosed in 13 patients. The most common diseases accompanying OSA were: systemic hypertension (46%), coronary heart disease (29%), diabetes (12%), and COPD (9%). Majority of OSA patients (61%) were obese (BMI > 30 kg/m2), 32% were over weight (BMI 25-30 kg/m2). Only 7% had normal body weight (BMI 20-25 kg/m2). Long-term (more than one year) compliance to treatment was found in 70% of patients prescribed CPAP.

[Acromegaly and sleep apnoea syndrome--case report]. / Akromegalia u chorego z zespolem bezdechu sennego.

We studied 65-year old, obese man suspected of obstructive sleep apnoea. He gave a history of loud snoring and excessive daytime sleepiness. We confirmed sleep apnoea syndrome during limited polysomnography with Polymesam (RDI--45/h, ODI--47/h). Patient had mainly obstructive episodes, however central and mixed apnoeas constituted about 1/3 of all episodes. During hospitalization we observed exacerbation of coronary artery disease and diagnosed diabetes. Patient's coarsened facial features, macroglossia and large hands led us to suspect acromegaly. Brain MR study revealed small pituitary adenoma. Plasma GH and IGF-1 concentrations were increased. Active acromegaly was diagnosed and was proposed a surgical treatment but he refused. Symptoms of sleep apnoea relieved after CPAP treatment. After one year patient's condition remained stable.

[Predictors of success in smoking cessation among participants of spirometric screening for COPD]. / Czynniki okreslajace sukces w porzucaniu palenia u osób uczestniczacych w srodowiskowych badaniach spirometrycznych.

The aim of the study was to evaluate factors that could predict smoking cessation after a minimal antismoking counseling during spirometric screening for COPD. Every subject filled-in a simple questionnaire on clinical signs of COPD and tobacco habit, had a spirometry performed according to ATS standards and received a short antitobacco counseling together with a booklet on how to quit smoking. Out of 800 smokers over 40 years of age, smoking history of more than 10 packyears, screened for COPD in 1999, four hundred were invited a year later for a follow-up spirometry and evaluation of anti-smoking intervention. Of 383 patients, who responded to the invitation (208 M and 175 F, mean age 56.6 +/- 10.7 yrs), 52 (13.6%) quit smoking for one year and another 48 (12.5%) quit smoking temporarily and than resumed smoking. Smokers who permanently succeeded in quitting smoking were older (60.5 vs 55.9 years p < 0.01), started smoking later (age at starting smoking 22 vs 19.5 years p < 0.001), had a shorter tobacco exposition (28.8 vs 34.3 packyears p < 0.05), had lower lung function (FEV1%pred 80.5 vs 89.2% p < 0.05) and were less nicotine dependent (FTQ score 1 vs 4.8 p < 0.00001).

[Obstructive sleep apnea and risk factors for coronary artery disease]. / Obturacyjny bezdech senny a czynniki ryzyka choroby niedokrwiennej serca.

STUDY AIM: Obstructive sleep apnoea (OSA) is strongly associated with obesity, especially abdominal obesity. Obesity in turn is a well-known risk factor for coronary artery disease (CAD). The aim of our study was to evaluate the relationship between OSA severity and CAD risk factors. MATERIAL AND METHODS: The sample consisted of 73 subjects (mean age +/- SE, 46.7 +/- 1 years) referred to a sleep laboratory. Subjects were either: 1. obese with OSA (O-OSA group n = 35; body mass index, BMI l 30 kg/m2; apnoea/hypopnoea index, AHI > 35), 2. non-obese with OSA (BO-OSA group n = 14; BMI < 27 kg/m2; AHI > 35), or 3. obese without OSA (O-Z group n = 24; BMI l 30 kg/m2; AHI < 5). All subjects underwent full overnight polysomnography. Blood samples were taken from all subject, for fasting levels of insulin (INS), glucose (GLU), total, HDL and LDL cholesterol, triglyceride (TG) and uric acid (UA). RESULTS: O-OSA had significantly higher INS and UA levels (p < 0.05) compared to BO-OSA and O-Z. GLU and lipid levels were comparable in the studied groups. GLU level correlated (p < 0.05) negatively to minimum oxyhemoglobin saturation (SAT-MIN) and positively to neck circumference. TG and UA levels were correlated (p < 0.05) positively to AHI and negatively to SAT-MIN. UA level was also positively correlated (p < 0.05) to BMI, waist/hip circumference ratio (WHR), and INS level. INS level correlated (p < 0.05) positively to AHI, T90, WHR and UA, and negatively to SAT-MIN and mean oxyhemoglobin saturation. After adjusting for the influence of OSA and obesity (multiple regression analysis), we found independent negative correlations (p < 0.05) between: GLU level and SAT-MIN, UA level and SAT-MIN, and INS level and SAT-MIN. An independent, positive correlation (p < 0.05) was found between TG level and AHI. CONCLUSIONS: Results of our study suggest that OSA increases the risk of coronary artery disease by increasing plasma levels of glucose, triglyceride and insulin, independent of obesity.

[Malfunction of some immunologic functions in patients with obstructive sleep apnea]. / Zaburzenia niektórych funkcji ukladu odpornosciowego u chorych na obturacyjny bezdech senny (OBS).

Hypoxia and sleep disorders may result in an impairment of immune system in patients with obstructive sleep apnea (OSA). Therefore we studied mitogenic stimulation of peripheral blood lymphocytes by PHA (1 microgram/ml) by measurement of 3H-thymidine incorporation, metabolic activity of neutrophils measured by chemiluminescence (CL), immunoglobulins (IgG, IgA and IgM) concentration in serum (radial immunodiffusion) and TNF-alpha concentration in serum (ELISA), and E-rosette tests (with theophylline) in 57 obese patients with severe OSA. In OSA patients severe impairment of f-MLP-induced granulocyte chemiluminescent activity was observed.

[Comparison of automatic (AUTO-CPAP)and "manual" CPAP pressure titration in patients with obstructive sleep apnea]. / Porównanie automatycznego (AUTO-CPAP) i "recznego" doboru cisnienia leczniczego u chorych na obturacyjny bezdech senny (OBS).

UNLABELLED: Auto-CPAP gives an opportunity to decrease costs of evaluating patient with OSA, replacing manual titration of pressure during PSG. The aim of this study was to compare automatic (auto-CPAP) and manual CPAP pressure titration in patients with OSA. We studied 50 obese patients (BMI--35 +/- 6 kg/m2), mean age 52.4 +/- 9.4 years with severe OSA, mean: AHI--62.9 +/- 22.1, mean overnight SaO2--89.1 +/- 3.7%, T90--54.4 +/- 29.6%. Two polysomnographies were performed: first when patient slept with CPAP and pressure was titrated manually by a technician and second on auto-CPAP device. Both methods had similar efficacy in reduction of AHI (< 10/h) and hypoxaemia, despite lower pressure established during auto-CPAP mode preventing apnoeas and hypopnoes during 90% of sleep time (8.2 +/- 1.7 cm H2O) compared to manual CPAP titration (9.2 +/- 1.7 cm H2O) (p < 0.05). CONCLUSION: Auto-CPAP seems to be a reliable alternative to manual titration of the therapeutic pressure in patients with OSA. This may help to cut a waiting list for PSG of patients suspected of OSA.

[Compliance to treatment recommendations in patients with obstructive sleep apnea at least one year after diagnosis]. / Stosowanie sie do zalecen leczniczych chorych na obturacyjny bezdech senny (OBS) w co najmniej rok po ustaleniu rozpoznania.

UNLABELLED: 102 OSA patients, qualified for nCPAP treatment at least one year ago were investigated by questionnaire and direct examination. CPAP device has been used by 76 patients (75%). Other subjects (26 persons) did not use it for various reasons. Subjects treated (Group L) and not treated (Group NL) were compared. Before qualifying for nCPAP treatment, Group L compared to Group NL, had significantly higher apnoea/hyponoea index, AHI (p < 0.001) and more severe hypoxaemia during sleep (p < 0.01). Subjects of Group L were more obese (p < 0.01) and smoked more cigarettes per day (p < 0.05) than Group NL. Group L patients have been using nCPAP for 6.3 +/- 0.2 nights per week and 6.4 +/- 0.2 hours per night. From variables characterizing OSA and obesity, the intensity of nCPAP usage positively correlated with AHI (p < 0.05) and negatively with severity of daytime sleepiness (p < 0.001). Among Group L patients, 93% reported general improvement, 84% woke up refreshed and rested in the morning and 70% did not feel sleepy during the daytime. Concentration improved in 66% of treated patients. Main complaints were associated with rhinitis (38%), uncomfortable mask (34%) or air leaks around the mask (26%), dryness in throat and nose (33%), shallow, unquiet sleep with frequent awakenings (about 31%), chest pain (23%) or headache (22%). 33% of subjects complained of machine noise, troubling sleep partner. CONCLUSIONS: The acceptance of nCPAP treatment was 75% and depended on the OSA severity. nCPAP device was effective in OSA treatment, mild side effects were reported by around one third of studied patients.

[Effect of nocturnal hypoxia on pulmonary hemodynamics in patients with obstructive sleep apnea]. / Wplyw nocnego niedotlenienienia krwi na krazenie plucne chorych na obturacyjny bezdech senny (OBS).

Effects of apnoea induced nocturnal hypoxia on pulmonary haemodynamics (PH) in pts with OSA are still under debate. We studied PH in 67 pts (64 M and 3 F) mean +/- SD: age 45 +/- 8 years, with severe OSA, AHI 62 +/- 22. Patients had normal spirometry: FVC 98 +/- 15% N, FEV1 97 +/- 16% N and arterial blood gases--PaO2 72 +/- 10 mmHg, PaCO2 40 +/- 4 mmHg. PH were studied using Swan-Ganz thermodilution catheter. PH were within normal range: right atrial pressure 4.2 +/- 2.7 mmHg, right ventricular systolic/enddiastolic pressure 28.1 +/- 7.1/5.0 +/- 3.3 mmHg, mean pulmonary artery pressure (PAP) 15.8 +/- 4.6 mmHg, mean pulmonary wedge pressure (PW) 6.8 +/- 3.1 mmHg, cardiac output (CO) 5.6 +/- 2.2 L/min. and pulmonary vascular resistance (PVR) 150 +/- 83 dyn.sec.cm-5. During exercise (44 pts) PAP rose from 15.8 +/- 4.3 to 29.8 +/- 9.4 mmHg, PW rose from 6.8 +/- 3.2 to 12.6 +/- 6.8 mmHg and CO from 4.9 +/- 1.9 to 9.2 +/- 4.2 L/min. All patients presented with nocturnal desaturations. Mean oxygen saturation (SaO2 mean) was: 87.4 +/- 5.4%, minimal saturation (SaO2 min) was 57.4 +/- 15.9%. Time spent in desaturation SaO2 < 90% (T90) was 50.7 +/- 26.5%. Results of PH investigations were related to results of pulse oximetry. Linear regression analysis showed week negative correlations between SaO2 mean and: PAP (r = -0.37 p = 0.003), PVR (r = -0.37 p = 0.007), and positive correlation between T90 and PAP (r = 0.37 p = 0.008). We conclude that there is no diurnal pulmonary hypertension at rest in patients with severe OSA and normal lung function even in the presence of severe overnight nocturnal desaturations. In half of studied patients we observed pulmonary hypertension during exercise.

[Effects of nocturnal desaturation on pulmonary hemodynamics in patients with overlap syndrome (chronic obstructive pulmonary disease and obstructive sleep apnea)]. / Wplyw nocnego niedotlenienia na cisnienie w tetnicy plucnej u chorych z zespolem nakladania (przewlekla obturacyjna choroba pluc i obturacyjny bezdech senny).

We studied pulmonary haemodynamics and nocturnal desaturation in 17 patients with an overlap syndrome (OS), all males, mean age 51.4 +/- 8.3 years, mean BMI 37 +/- 4.2 kg/m2. Diagnosis of COPD was based on pts history, clinical examination, lung function tests and chest radiography. Spirometry showed: FVC 2.7 +/- 0.7 L (59 +/- 16% N), FEV1 1.5 +/- 0.7 L (43 +/- 16% N), FEV1% FVC 54 +/- 13%, Raw 0.58 +/- 0.4 kP.s/L, RV 3.3 +/- 1.2 L (144 +/- 51% N), TLC 6.6 +/- 1.3 L (100 +/- 14% N) and RV% TLC (49.5 +/- 12.1%. Arterial blood gas values were: PaO2 56.9 +/- 9.5 mmHg, PaCO2 46.9 +/- 9.8 mmHg, pH 7.37 +/- 0.05. Mean apnoea/hypopnoea index (AHI) was 63.9 +/- 18.9. Pulmonary haemodynamics at rest (Swan Ganz thermodilution catheter) were: mean pulmonary artery pressure (PAP-SP) 24.2 +/- 7.4 mmHg, mean pulmonary wedge pressure (PW-SP) was 9.1 +/- 7.3 mmHg, cardiac output (CO-SP) was 5.6 +/- 2.3 L/min. and pulmonary vascular resistance (PVR) was 229 +/- 97 dyn.sec.cm-5. During exercise (40 Watts, 7 mins, in 8 pts) PAP rose from 19 +/- 6 mmHg to 41.2 +/- 15.1 mmHg, PW rose from 7.4 +/- 7.2 mmHg to 11 +/- 10.2 mmHg, CO rose from 5.8 +/- 2.7 L/min to 12.7 +/- 2.4 L/min. Overnight pulse oximetry showed: mean oxygen saturation (SaO2 mean) 80.2 +/- 8.5%, minimal saturation (SaO2 min) was 50.7 +/- 19.7%. Time spent in desaturation SaO2 < 90% (T 90) was 76.9 +/- 25.7%. We conclude that pts with OS have resting pulmonary hypertension and elevated PVR. During low grade exercise the rise in PAP was highly abnormal. Statistical analysis showed no correlations between nocturnal SaO2 and diurnal pulmonary haemodynamics data.

[Respiratory response to inspiratory resistive load changes in patients with obstructive sleep apnea syndrome]. / Odpowiedz oddechowa na zmiane oporu wdechowego u chorych na obturacyjny bezdech senny.

Patients with OSA have many episodes of increased airway resistance because of repeated collapses of upper airways during night. The aim of this work was to evaluate respiratory response during chemical stimulation without and with added inspiratory resistive load (10 cmH2O/L/sec). The studies were performed during quiet breathing with air and during hypercapnic and hypoxic rebreathing tests without and with inspiratory resistive loading in 23 obese (BMI = 34.4 +/- 4.3 kg/m2) patients with OSA and in 10 healthy subjects with similar weight (BMI = 32.4 +/- 4.3 kg/m2). The measurements of respiratory responses (ventilation, mouth occlusion pressure) were performed with the use of computerized equipment. During quiet breathing in response to added load an increase of P0.1 in controls and in OSA patients was observed. During hypercapnic stimulation the ventilatory response with additional load decreased in patients as well as in controls. The slope of mouth occlusion pressure response increased significantly in controls (from 4.40 to 6.83 cmH2O/kPa, p < 0.001) and slightly weaker in OSA patients (from 4.21 to 5.43 cmH2O/kPa, p < 0.05). Although the difference between the slopes was not significant, we found that the absolute increase of P0.1 measured at point 8 kPa of PEtCO2 during loaded breathing was significantly smaller in OSA patients in comparison to controls. (2.1 vs. 10.3 cm H2O; p < 0.001). During hypoxic stimulation occlusion pressure responses were similar in both examined groups. In conclusion we postulate that OSA patients have impaired respiratory compensation of additional inspiratory load, what was demonstrated during hypercapnic rebreathing test.

Incidence of nocturnal desaturation while breathing oxygen in COPD patients undergoing long-term oxygen therapy.

STUDY OBJECTIVE: It is suggested that oxygen flow be increased by 1 L/min during sleep in COPD patients undergoing long-term oxygen therapy (LTOT) in order to avoid nocturnal desaturations. The purpose of this study was to investigate the occurrence of nocturnal desaturations while breathing oxygen in COPD patients receiving LTOT. SETTING: Inpatient/university hospital. PATIENTS: We studied 82 consecutive COPD patients. Their functional characteristics were as follows (mean +/- SD): FVC, 2.15 +/- 0.69 L; FEV(1), 0.87 +/- 0.33 L; PaO(2), 51.6 +/- 5 mm Hg; and PaCO(2), 47 +/- 8 mm Hg. MEASUREMENTS: Overnight pulse oximetry (PO) was performed twice: (1) while breathing air and (2) while breathing supplemental oxygen assuring satisfactory diurnal resting oxygenation (mean PaO(2) during oxygen breathing, 67 +/- 6 mm Hg; mean arterial oxygen saturation [SaO(2)] during oxygen breathing, 93%). RESULTS: PO performed while patients were breathing air showed a mean overnight SaO(2) of 82.7 +/- 6.7%. Patients spent 90% of the recording time with an SaO(2) of < 90%. While breathing oxygen, 43 patients (52.4%) remained well oxygenated. Their mean overnight SaO(2) while breathing oxygen was 94.4 +/- 2.1%, and time spent with saturation < 90% was 6.9 +/- 8.6%. Thirty-nine patients (47.6%) spent > 30% of the night with an SaO(2) of < 90% while breathing supplemental oxygen. Their mean overnight SaO(2) while breathing oxygen was 87.1 +/- 4.5%, and time spent with an SaO(2) of < 90% was 66.1 +/- 24.7% of the recording time. Comparison of ventilatory variables and daytime blood gases between both groups revealed statistically significantly higher PaCO(2) on air (p < 0.001) and on oxygen (p < 0. 05), and lower PaO(2) on oxygen (p < 0.05) in the group of patients demonstrating significant nocturnal desaturation. CONCLUSIONS: We conclude that about half of COPD patients undergoing LTOT need increased oxygen flow during sleep. Patients with both hypercapnia (PaCO(2) > or = 45 mm Hg) and PaO(2) < 65 mm Hg while breathing oxygen are most likely to desaturate during sleep.