الفهرس 
Acknowledgement
An Overview of Obstructive Sleep ApneaOnly 14 pages are availabe for public view
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Abstract
Obstructive sleep apnea (OSA) syndrome is a common but often unrecognized disorder caused by pharyngeal collapse during sleep and characterized by frequent awakenings, disrupted sleep and consequent excessive daytime sleepiness. The inspiratory airflow can be either reduced (hypopnea) or completely absent (apnea). OSAS is defined as five or more episodes of apnea or hypopnea per hour of sleep. With the increasing epidemic of obesity, the most important risk factor for OSA, prevalence of the disease will increase over the coming years thus representing an important public-health problem. In fact, it is now recognized that there is an association between OSA and hypertension, metabolic syndrome, diabetes, heart failure, coronary artery disease, arrhythmias, stroke, pulmonary hypertension, neurocognitive and mood disorders. Diagnosis is based on the combined evaluation of clinical manifestations and objective sleep study findings. Cardinal symptoms include snoring, sleepiness and significant reports of sleep apnea episodes. Polysomnography represents the gold standard to confirm the clinical suspicion of OSA syndrome, to assess its severity and to guide therapeutic choices. Behavioral, medical and surgical options are available for the treatment. Continuous positive airway pressure (CPAP) represents the treatment of choice in most patients. CPAP has been demonstrated to be effective in reducing symptoms, cardiovascular morbidity and mortality and neurocognitive sequelae, but it is often poorly tolerated. The results of clinical studies do not support surgery and pharmacological therapy as first-line treatment, but these approaches might be useful in selected patients. A better understanding of mechanisms underlying the disease could improve therapeutic strategies and reduce the social impact of OSA syndrome [Massimo et al., 2012].
Pulmonary function test (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity of pulmonary impairment. Pulmonary function testing has diagnostic and therapeutic roles and helps clinicians answer some general questions about patients with lung disease. Pulmonary function testing is a diagnostic and management tool used for a variety of reasons, such as: chronic shortness of breath, Asthma, chronic obstructive pulmonary disease, Restrictive lung disease, Preoperative testing, Impairment or disability. They are noninvasive tests that show how well the lungs are working. The tests measure lung volume, capacity, rates of flow, and gas exchange. This information can help the healthcare provider diagnose and decide the treatment of certain lung disorders.
There are 3 types of disorders that cause problems with air moving in and out of the lungs:
• Obstructive: This is when air has trouble flowing out of the lungs due to airway resistance. This causes a decreased flow of air.
• Restrictive: This is when the lung tissue and/or chest muscles can’t expand enough. This creates problems with air flow, mostly due to lower lung volumes.
• Mixed: Combined obstruction and restriction is more commonly caused by a mixture of parenchymal and non-parenchymal diseases than by a single pulmonary entity.
PFT can be done with 2 methods. These 2 methods may be used together and perform different tests, depending on the information that your healthcare provider is looking for:
• Spirometry. A spirometer is a device with a mouthpiece hooked up to a small electronic machine.
• Plethysmography. You sit or stand inside an air-tight box that looks like a short, square telephone booth to do the tests.•PFT measures are : Tidal volume (VT), Minute volume (MV), Vital capacity (VC), Functional residual capacity (FRC), Residual volume (RV), Total lung capacity (TLC), Forced vital capacity (FVC), Forced expiratory volume in one second (FEV1), Forced expiratory flow (FEF) and Peak expiratory flow rate (PEFR).•Normal values for PFTs vary from person to person. The amount of air inhaled and exhaled in the test results are compared to the average for someone of the same age, height, sex, and race. Results are also compared to any of the previous test results. If person has abnormal PFT measurements or if the results have changed, it means there’s a problem anywhere. [Kociánová & Vnitrni Lekarstvi , 2018].The main aim of this study is :- 1- Evaluate pulmonary function abnormalities in patients with documented Obstructive Sleep Apnea (OSA) with and without chronic Obstructive Pulmonary Diseases (COPD).2-Assess inspiratory muscles dysfunction in patients with OSA.3-To correlate the PFTs parameters with BMI, AHI% and among OSAS severity.
This study was done and conducted on sixty-six patients (including 34 males and 32 females) with Obstructive Sleep Apnea (OSA) with and without chronic Obstructive Pulmonary Diseases (COPD).
The patients were selected from Chest department of Assiut University Hospital, from June 2017 to April 2018. An informed written consent was obtained from all the patients. The study was approved by the Faculty of Medicine Ethics Committee, Assiut University.
Patients were classified into 2 groups; group (I): Pure OSA, and group (II): COPD & OSA{Overlap Syndrome}. COPD was detected according to symptoms and spirometry which shows FEV1/FVC < 70% [Gold Guideline, 2017].This study was a prospective observational study and it was occurred in Pulmonary Function Lab and Sleep Study Lap of Chest Department, Faculty Of Medicine, Assiut University Hospital .
Patient Inclusion criteria :- We included all patients who were diagnosed as Obstructive Sleep Apnea in Sleep Lab of Assiut University Hospital with and without COPD. Exclusion criteria : We excluded the patients which had a history of :- 1.Age <18 years old. 2.Severe cardiovascular diseases (e.g: cardiac arrhythmias, ventricular tachycardia, frequent or multifocal premature ventricular beats). 3.Drug abuse. 4.Use of medication that may interfere with the sleep structure, such as hypnotic drugs or stimulants of the central nervous system. 5. Clinical evidence of neuromuscular disease. 6. Patient with mental disorders .
* Informed consent was obtained from all subjects before inclusion into this study.All patients were subjected to the following :-1- Full Clinical Assessment :-Including name, age , sex , Body Mass Index (BMI) , smooking history , neck and waist circumference will be performed for all patients.
E- History Taking :-Including daytime symptoms and night time symptoms C- Epworth Sleepiness scale (ESS) :-
The ESS is a self-administered, eight-item scale that takes few minutes to respond, These questions were developed based on identified low stimulus activities promoting sleepiness.2- Sleep Study ( Polysmnography ) (PSG) :-Overnight PSG remains the gold standard for diagnosis of OSAS. Full attended nocturnal Polysomnography was performed for all patients in the sleep lab of chest department of Assiut university hospital. The following parameters were recorded :{Electro-encephalography (EEG), Electro-oculography (EOG), Chin electromyography (EMG), Leg EMG, Electro-cardiography (ECG), Oxygen saturation, Chest and abdominal wall movements, Air flow signals, Sleep position and Microphone for snoring}.
3- Arterial Blood Gases (ABG) The blood sample was analyzed for pH, PCO2, PO2 , oxygen saturation and HCO3 (Blood gas analyzer 4- Pulmonary Function Tests(PFTs) :-
Pulmonary function tests were performed for all patient at Pulmonary Function Unit at Assiut University; in the form of:
A- Spirometry and flow- volume curves
B- Body PlethysmographyC- Diffusion Capacity (DLCO)D- Respiratory Muscles Strength
Statistical analysis of the presenting data revealed :-This study included 66 patients with clinical history of obstructive sleep apnea syndrome (OSAS) admitted to Chest Department Assiut University Hospital, they are 34 males and 32 females (1.06:1), with mean age [47.18 ± 8.93, range 34.0 – 75.0]; 75.7% aged above 40 years old. The mean BMI is [37.85 ± 10.77, range26.3 - 49.7kg/m2], Neck circumference is 42.26 ± 5.38, (range 37.0 - 47.0 cm) and Waist circumference is105.63 ± 24.18 (range 66.5-150.0 cm).
As regards clinical symptoms of OSAS patients, according to day-time symptoms; Excessive day time sleepiness (84.4%) was more than morning headaches (50%), are recorded in the history of patients. Snoring, was the only night symptom presented in all patients (100% ) but with different grades of other symptoms followed by frequent nocturia (83.3%), disturbed sleep rhythm (75.8%), witnessed apnea (69.7%) and bad dreams (30.3%).
A reduced FVC, FEV1 and normal FEV1/FVC (actual and percentage of predicted) suggests a restrictive pattern in the studied group. The decreased FEF, FIF 50% is characteristic to upper airway obstruction in apneic patients.
The mean of PImax% was diminished or still normal (90.44 ± 47.30%) [Normal value is 60-140% of average in population with similar age, sex and body composition].
The mean of TLC% was (75.67 ± 18.42), FRC % was (54.61 ± 24.45) and RV% was (85.36 ± 20.20).
The mean of DLCO was (81.20 ± 19.69), that indicate increase the DLCO with OSAS.
There wasn’t significant difference in parameters of pulmonary function test (spirometry), lung volumes, PImax and DLCO among OSAS groups with different severity.There was a significant decrease in all spirometric parameters in combined OSAS compared to pure OSAS. There was a significant increase in TLC, FRC actual and RV actual and % (P<0.001) in combined OSAS group compared to pure OSAS group, decrease in PImax in patients with comorbidities compared to pure OSAS (P<0.001) of (PImax actual and PImax%).
Also, there is significant decrease in diffusing capacity (DLCO) combined OSAS patient compared to pure OSAS group (P<0.02) Finally, there is significant correlation between OSAS severity based on AHI and obesity based on anthropometric measurement especially between age (r= 0.518, P<0.001), BMI (r= 0.323, P<0.01), neck circumference (r=0.326, P<0.01), and waist circumference (r=0.501, P<0.001) .Conclusion
OSAS alone is associated mainly by restrictive pattern of pulmonary function with increased FEV1/FVC , decrease TLC, FRC and RV compared to combined OSAS ( mostly overlap syndrome). The change in these spirometric parameters are not correlated to severity of OSAS based on AHI but it is rather correlated to severity of obesity (BMI, neck circumference and waist circumference). The DLCO was significantly increased in pure OSAS compared to combined OSAS. Finally Pimax is significantly impaired in OSAS group -but not correlated to AHI- with more decrease in inspiratory muscle power in combined OSAS group. Obesity and presence of comorbidities as COPD in OSAS patients most probably are the main factors causing pulmonary function changes in this group.