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PubMed1997

[The usefulness of a computer program Oxygen Status Algorithm (OSA) with particular consideration of oxygen parameters in the Clinic of Chest Diseases].

The traditional parameters such as the oxygen tension (pO2) and the haemoglobin oxygen saturation (sO2) obtained from arterial blood samples are not always sufficient in clinical practice. The purpose of the study is to present the examples where pO2 and sO2 even in combination may provide misleading information. We examined patients with bronchial asthma, respiratory insufficiency and with extrinsic allergic alveolitis who had been admitted to the Chest Disease Department. We used the Oxygen Status Algorithm (OSA) to calculate the new oxygen parameters. These new parameters are: 1) oxygen extraction tension px defined as the tension required to extract 2.3 mmol of oxygen per liter of blood, 2) the concentration of extractable oxygen cx defined as the concentration of oxygen extracted per liter of blood at a tension of 5.0 kPa, 3) the oxygen compensation factor (Qx), derived as 2.3 mmol/l/cx. This data defines the blood oxygen availability. Additional parameters such as effective hemoglobin concentration ceHb (equivalent of oxygen capacity) and the hemoglobin oxygen affinity (p50) inform us of the oxygen supply to the tissue. The results show that the new oxygen parameters are helpful in undertaking decisions of starting therapy and its duration.

Adult↗
PubMed2003

Nitric oxide (NO) and obstructive sleep apnea (OSA).

Nitric oxide (NO) and obstructive sleep apnea are inseparable. Obstructive sleep apnea could be described as the intermittent failure to transport the full complement of nasal NO to the lung with each breath. There NO matches perfusion to ventilation. NO is utilized by the efferent pathways that control the unequal, inspiratory battle between the pharyngeal dilators and the closing negative pressures induced by the thoracic musculature. Recurrent cortical arousals are a major short-term complication, and the return to sleep after each arousal uses NO. The long-term complications, namely hypertension, myocardial infarction, and stroke, might be due to the repeated temporary dearth of NO in the tissues, secondary to a lack of oxygen, one of NO's two essential substrates.

Arousal↗
PubMed1997

Comparison of two dental devices for treatment of obstructive sleep apnea syndrome (OSAS).

Previous case reports have indicated dental devices can be an effective nonsurgical treatment for snoring and obstructive sleep apnea. This pilot study evaluated the effectiveness of two intraoral devices in reducing the Respiratory Disturbance Index (RDI) and Epworth Sleepiness Scale (ESS) scores in a group of 24 adult volunteers with a history of loud snoring. Subjects were randomly assigned to two groups. Twelve subjects were fitted with a dental device designed to increase vertical dimension and protrude the mandible (device A). The other 12 subjects received a different device designed to minimally increase vertical opening without protruding the mandible (device B). Unattended home sleep monitoring (Edentrace II Digital Recorder, Edentech Corp.) was used to compute RDI at two time periods: (T0) before using any dental device and (T1) while using a dental device 2 weeks after the initial delivery date. The mean RDI and ESS scores at T0 for subjects in the device A group were 35.6 +/- 28.4 and 12.0 +/- 3.9, respectively. Means for the same measures at T1 were 21.1 +/- 21.4 and 8.2 +/- 4.0. For subjects in the device B group, means for RDI and ESS scores at T0 were 36.5 +/- 43.7 and 13.0 +/- 4.5, the means at T1 were 46.8 +/- 47.0 and 12.5 +/- 5.7. The effectiveness of the two devices was estimated by comparing the difference in RDI scores from T0 to T1 for the 10 subjects who were using device A and completed the study and the 8 subjects who were using device B and completed the study. Six subjects withdrew for various reasons. From T0 to T1, device A reduced RDI scores in 9 of 10 subjects, with a mean reduction in RDI of 14.5 (p < or = 0.05) and in ESS score of 3.8 (p < or = 0.005). Device B showed no change or an increased RDI score in 8 of 8 subjects. Seven of the eight subjects who showed no improvement in RDI with device B were then fitted with device A. Four of these seven subjects showed a reduction in RDI and five showed a reduction in ESS after using device A for 2 weeks. The mean reduction in RDI and ESS was 2.4 +/- 19.8 and 2.4 +/- 3.0, respectively. Hence, we conclude that a dental device that advances the mandible and increases the vertical dimension to open the upper airway is more effective in reducing the number of apneic and snoring events during sleep than one which does not.

Adult↗
PubMed2000

Vigilance stages and performance in OSAS patients in a monotonous reaction time task.

OBJECTIVES: To develop improved methods for objective assessment of daytime vigilance. This is important in the diagnosis and therapy control of sleep disorders associated with excessive daytime sleepiness (EDS). METHODS: Twenty-one patients with EDS due to obstructive sleep apnea were recorded during a daytime 90 min reaction time (RT) test in a monotonous situation. Two EEG, two EOG and a submental EMG channel were recorded simultaneously. The recordings were divided into short, stationary segments of variable length (0.5-2 s) and classified into 7 stages using our previously described system, which includes additional stages for drowsiness. RESULTS: The duration of RT was linearly correlated to the vigilance state (P<0.05). The appearance of slow eye movements (SEM) was more consistently related to performance impairment than EEG changes. CONCLUSIONS: Our system can provide a better tracking of vigilance changes than the standardized sleep stage scoring. A 1-2 h test is useful in the assessment of the performance of a subject suffering from EDS. We found that SEMs indicate more sensitive and consistent EDS-related performance impairment than changes in EEG activity.

Adult↗
PubMed2003

Effects of modafinil on sustained attention performance and quality of life in OSA patients with residual sleepiness while being treated with nCPAP.

BACKGROUND: Some patients with obstructive sleep apnea/hypopnea syndrome (OSA/HS) who are regular users of nasal continuous positive airway pressure (nCPAP) therapy continue to experience daytime sleepiness that impairs performance and quality of life. A randomized, double-blind, placebo-controlled, parallel-group study was conducted to determine the effect of modafinil on sustained attention performance and functional quality of life in OSA/HS patients with residual daytime sleepiness, who were regular users of nCPAP therapy. METHODS: Seventy-seven patients received modafinil (200 mg/day, week 1; 400 mg/day, weeks 2-4) and 80 patients received matching placebo once daily for 4 weeks. Sustained attention performance on the psychomotor vigilance task (PVT) and functional status and quality of life using the Functional Outcomes of Sleep Questionnaire (FOSQ) were measured. RESULTS: The frequency of lapses of attention during PVT performance was significantly decreased, and both the median and slowest reaction times were significantly improved in patients receiving nCPAP plus modafinil compared with those receiving nCPAP plus placebo (P=0.010 for the number of lapses [transformed], P=0.023 for the median reaction time, and P=0.014 for the reciprocal of the 10% slowest reaction times). Treatment with nCPAP plus modafinil significantly improved the FOSQ total score (weeks 1 and 4), the vigilance subscale score (weeks 1 and 4), and the activity level subscale score (week 4) compared with treatment with nCPAP plus placebo (all P<0.05). CONCLUSIONS: Consistent with previous results for objective and subjective measures of sleepiness, modafinil used adjunctively improved performance on a test of behavioral alertness and reduced functional impairments in patients with OSA/HS who were regular users of nCPAP therapy but still experiencing sleepiness.

Adult↗
PubMed1999

Prognostic value of lung function and pulmonary haemodynamics in OSA patients treated with CPAP.

The aim of the present study was to determine survival rates of obstructive sleep apnoea patients treated with continuous positive airway pressure (CPAP) and to investigate the prognostic value of pretreatment lung function and pulmonary haemodynamics. Two hundred and ninety-six patients, exhibiting > or = 20 apnoeas plus hypopnoeas per hour of sleep, were included. Patients were treated with nasal CPAP and regularly followed up. The cumulative survival rates were 0.96 (95% confidence interval (CI): 0.94-0.99) at 3 yrs and 0.93 (95% CI: 0.91-0.97) at 5 yrs. Most patients died from cardiovascular disease. Apart from age, covariates associated with a lower survival were the presence of a heavy smoking history, a low vital capacity, a low forced expiratory volume in one second (FEV1) and a high mean pulmonary artery pressure. Only three covariates were included by forward stepwise selection in the multivariate analysis, smoking habit (>30 pack-yrs), age and FEV1. The observed survival rates of the group as a whole were similar to those of the general population matched in terms of age, sex and smoking habit, except for patients between 50 and 60 yrs old who had reduced survival. This difference disappeared when patients of the present study with an associated chronic obstructive pulmonary disease were excluded from the comparison. In conclusion, survival of obstructive sleep apnoea patients treated with nasal continuous positive airway pressure is near to that of the general population. The prognosis is worse in subgroups of patients with a history of heavy smoking and with an associated chronic obstructive pulmonary disease.

Female↗
PubMed2005

Positive airway pressure therapy of OSA.

Positive airway pressure is standard therapy for patients with obstructive sleep apnea. It comes in three basic varieties: (1) continuous positive airway pressure (CPAP), (2) bilevel positive airway pressure (BPAP), and (3) autotitrating positive airway pressure (APAP). When properly titrated, positive airway pressure devices minimize the number of sleep-related breathing disorder events, often producing dramatic results. Sleep-related breathing may completely normalize, specific stages of sleep may selectively rebound due to having been chronically suppressed, sleep microstructure may improve, and the patient may awaken feeling refreshed for the first time in years. The specific indications and criteria for recommending APAP, BPAP, and CPAP therapy are reviewed. The titration process is presented in a step-by-step manner and titration grading is explained. Issues surrounding the interface, acceptance, utilization, and side-effects are discussed. Finally, we present an assortment of approaches for troubleshooting clinical problems commonly encountered among patients being treated with positive airway pressure therapy.

Continuous Positive Airway Pressure↗
PubMed2001

A multi-institutional study of radiofrequency volumetric tissue reduction for OSAS.

OBJECTIVES: Radiofrequency volume reduction (RFTVR) is a minor procedure directed at reducing the tongue base volume to treat obstructive sleep apnea. Subjective and objective treatment effectiveness was evaluated. STUDY DESIGN AND SETTING: Two separate prospective, matched, nonrandomized, open enrollment treatment groups (RFTVR, n = 73 and nasal continuous positive airway pressure (CPAP, n = 99) were concurrently enrolled in a multicenter study. RESULTS: Fifty-six (76.7%) RFTVR completed PSG with a mean 5.4 +/- 1.8 treatments (13,394 +/- 5459 joules). Perioperatively, acute pain was mild to moderate; edema, mucosal erosion, paresthesia, tinnitus were infrequent; and speech, swallowing taste, or throat irritation were unchanged. Self-reported outcomes did not differ between RFTVR and CPAP groups. Mean apnea/hypopnea index decreased (40.5 +/- 21.5 to 32.8 +/- 22.6 events/hr, P < 0.01). Electrolyte solution injected predicted results (r = 0.43, P < 0.001). The most severe complication was abscess (1.1%). CONCLUSION: RFTVR improves apnea/hypopnea index. Improvement may be related to solution injected with treatment. RFTVR and CPAP clinical outcomes improvement were similar. CLINICAL SIGNIFICANCE: In mild obstructive sleep apnea, treatment of symptomatic outcomes with RFTVR may be an alternative to CPAP.

Adult↗