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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic alveolar hypoventilation is a classic feature of the "pickwickian syndrome" (i.e. obesity-hypoventilation syndrome) but in fact hypercapnia is observed in a minority of obstructive sleep apnoea syndrome (OSAS) patients. Most recent studies having included large numbers of unselected, consecutive OSAS patients agree on a prevalence of 10-20% of alveolar hypoventilation. The mechanisms of hypercapnia in OSAS are not fully understood but the determining factors of daytime respiratory insufficiency are probably the presence of a marked obesity, leading to the obesity hypoventilation syndrome and, principally, the association of OSAS with chronic obstructive pulmonary disease. This association (the so-called "overlap syndrome") is observed in >10% of OSAS patients. Bronchial obstruction is generally mild to moderate and may be asymptomatic. The severity of the nocturnal events (apnoeas, hypopnoeas) and a (possible) diminished chemosensitivity to hypercapnic and hypoxic stimuli do not appear to be determining factors of hypercapnia. The most important consequence of chronic alveolar hypoventilation is pulmonary hypertension which is only observed in patients with daytime arterial blood gases disturbances, and which can lead to right heart failure. When nasal continuous positive airway pressure fails to correct sleep-related hypoxaemia, supplementary O, must be given or another way of assisted ventilation (BIPAP) must be considered. In the most severe patients (diurnal PaO(2) <55 mmHg) conventional O(2) therapy (>or=16h/24h) is required in addition to nocturnal ventilation.
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PMID:Daytime hypoventilation in obstructive sleep apnoea syndrome. 1531 Apr 91

Sleep has effects on breathing, including changes in respiratory control, airways resistance and muscular contractility. These sleep-related modifications in the respiratory system do not induce adverse effects in healthy subjects, but may cause problems in patients with chronic obstructive pulmonary disease (COPD). Hypo-ventilation causes the most important gas-exchange alteration during sleep in COPD patients, leading to hypercapnia and hypoxemia, especially during rapid-eye-movement (REM) sleep. Blood gases alterations lead to increased arousals, sleep disruption, pulmonary hypertension and higher mortality. The presence of other sleep-related breathing disorders, like sleep apnea syndrome, may induce a more pronounced impairment of gas exchange, both during sleep and wakefulness, and development of symptoms like excessive daytime somnolence. Nocturnal oximetry is recommended to evaluate gas exchange during sleep in COPD patients. Sleep studies are usually indicated when there is a possibility of sleep apnea or obesity-hypoventilation syndrome. The role of non-invasive mechanical ventilation in managing COPD patients with nocturnal hypoventilation is discussed.
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PMID:Sleep disordered breathing in patients with chronic obstructive pulmonary disease. 1533 44

To investigate whether obesity is associated with alterations in respiratory chemosensitivity, we compared the ventilatory response to hypoxia (HVR) and hypercapnia (HCVR) in 9 obese men (BMI: 37.0+/-4.3 kg m(-2)) and 10 lean men (BMI: 25.8+/-4.8 kg m(-2)). HVR (DeltaVE, L min(-1) per DeltaSaO2, %) was measured by a progressive isocapnic hypoxia technique, and HCVR (DeltaVE/DeltaPETCO2, L min(-1)Torr(-1)) was measured by a progressive hypercapnic method. HCVR, was greater (p<0.001) in the obese men (2.68+/-0.78) than in the lean men (1.4+/-0.45) as was HVR (p<0.05) (1.26+/-0.65 versus 0.71+/-0.43, respectively). The difference (DeltaSaO2, 4.30+/-3.69 and 10.54+/-3.45 in the lean and obese men, respectively, p<0.01) between daytime (86+/-1 and 86+/-1%) and nighttime SaO2 (81+/-3 and 76+/-4%) at a simulated altitude of 3658 m was significantly (p<0.05) correlated with both HVR (r=0.51) and HCVR (r=0.48). These results suggest that chemosensitivity in mildly obese men is increased, not blunted. Furthermore, otherwise healthy, obese individuals have the potential for significant desaturation during sleep at high altitude possibly due to exaggerated sleep-disordered breathing.
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PMID:Exaggerated respiratory chemosensitivity and association with SaO2 level at 3568 m in obesity. 1573 78

The pathophysiology of upper-airway obstruction (UAO) is complex. Possible causes of UAO that may lead to acute respiratory failure, are as follows: infections like acute epiglottitis and croup, obstructing tumors in the base of the tongue, larynx or hypopharynx, aspirated food or liquid contents, obesity and anatomical variations. Management changes according to the pathogenesis of the disorder. In patients with severe carbon dioxide retention or apnea, emergency endotracheal intubation must be carried out. Hereby, we describe a 23-year-old patient with susceptible upper-airway anatomy and UAO occurred following an upper respiratory infection and complicated with pulmonary hypertension and pulmonary edema. Our patient seems to be one of the complicated UAO cases, with an unusual but critical clinical presentation, evaluated in a wide spectrum and nicely returned to life.
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PMID:Pulmonary hypertension and acute pulmonary edema in a 23-year-old male with a history of an upper respiratory tract infection. 1576 90

In obstructive sleep apnea syndrome (OSAS), repetitive episodes of apnea cause increased sympathetic nerve activity, increased surges in arterial blood pressure, swings in intrathoracic pressure, oxidative stres, hypoxia and hypercapnia. The association of OSAS with some diseases, having endothelial dysfunction in their physiopathology, such as hypertension, diabetes mellitus, obesity, coronary artery diseases, stroke and heart failure is common. Increased sympathetic nerve activity and also endothelial dysfunction which are the results of hypoxia, have important roles in vascular complications of OSAS. When compared with healthy population, an important endothelial dysfunction in OSAS patients and relationship between OSAS severity and endothelial dysfunction have been shown. In this review, the relationship between OSAS and endothelial dysfunction was overviewed.
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PMID:[Obstructive sleep apnea syndrome, endothelial dysfunction and coronary atherosclerosis]. 1625 93

Severe obesity is a chronic condition that is difficult to treat through diet and exercise alone. Gastrointestinal surgery for obesity (bariatric surgery) alters the digestive process by either restrictive surgical alterations or malabsorptive operations. Some 10-20% of patients who have weight-loss surgery require follow-up operations to correct complications. Hypoxemia after gastric bypass surgery for morbid obesity, a reported complication, can occur as early as 24 h post surgery. Two patients presented with severe hypoxia and were placed on veno-venous extracorporeal membrane oxygenation (ECMO). Patient No. 1 had an obstruction of the alimentary limb of the gastric bypass due to suture adhesions, and patient No. 2 had an incarcerated diaphragmatic hernia. While on ECMO, ventilation using a protective strategy (60% FiO2, pressure-controlled ventilation inspiratory pressure (PCV) IP 25-27, positive end-expiratory pressure (PEEP) 10-14, permissive hypercapnia) was employed. An inflow cannula to the level of the right atrium served as arterial outflow from the circuit to the patient, while the femoral vein served as venous inflow to the ECMO circuit. Although ECMO in adult respiratory failure is often used as the last resort due to serious associated adverse events, we report two patients with life-threatening complications from gastric bypass who were rescued, resuscitated to day 7, and uneventfully discharged from the hospital to home.
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PMID:Respiratory failure of two sp gastric bypass patients and subsequent rescue with extracorporeal membrane oxygenation. 1648 3

Obstructive sleep apnea syndrome is caused by upper airway collapse during inspiration, causing intermittent hypoxemia, hypercapnia, acidosis, sympathetic nervous system activation, and arousal from sleep. Nighttime blood pressure is higher, but unexpectedly, daytime hypertension occurs. The prevalence of hypertension is very high and the incidence of hypertension increases as the number of apneic and hypopneic events per hour rises. Obesity is a major predisposing factor for the development of obstructive sleep apnea. Daytime sleepiness, snoring, and breathing pauses are important symptoms to elicit from the patient or sleep partner. Resistant hypertension is an important clue. Overnight polysomnography is required for diagnosis. Weight loss, avoidance of nocturnal sedatives, cessation of evening alcohol ingestion, and avoidance of the supine position during sleep are initial therapeutic actions in mild obstructive sleep apnea syndrome. Continuous positive airway pressure is the treatment of choice for patients unable to find relief from lifestyle changes. Blood pressure modestly improves with treatment.
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PMID:Obstructive sleep apnea syndrome. 1702 91

Respiratory failure as a result of overload and/or reduced capacity of the respiratory muscles is the most common cause of unsuccessful weaning and the need for long term mechanical ventilation. Chronic obstructive pulmonary disease (COPD) is the most common underlying cause leading into long term mechanical ventilation. The most important clinical parameter for fatigue of the respiratory muscles is the rapid shallow breathing index. Other essential factors which impact weaning failure, are the underlying diseases (e. g. neuromuscular disease or heart failure), micro- and macro aspiration, malnutrition, anemia and obesity. A protocol based strategy to discontinue mechanical ventilation and the use of weaning predictors are helpful. Nonetheless the experienced physician is irreplacable in the weaning process. Reconditioning of the respiratory muscles is the main focus during weaning after long term mechanical ventilation and all therapeutic measures should be targeted to unload the fatiguing respiratory muscles. With the widely used assisted ventilation modes, the inspiratory work of breathing is still significantly increased. Only controlled mechanical ventilation (pressure- or volume controlled), which may also be applied to unsedated patients when individually adapted, offers the best possible relief and recovery of the respiratory muscles. Additional strategies, such as the balancing of anemia, reduction of the respiratory drive with i. e. morphine derivates, oxygen therapy during spontaneous-breathing trials and supine position for patients with obesity contribute to the recovery. Particularly patients with chronic lung diseases with hypercapnia benefit from the use of non invasive ventilation (NIV) after extubation to prevent postextubation failure and even after tracheostomy. However, NIV should only be applied under close monitoring and in cooperative patients, always considering the limits of the method. Dying under mechanical ventilation in the end stage illness is still a challenge for all involved persons. In the end stage of their disease for some patients it is possible to discontinue mechanical ventilation so they can spend the last period of their lives on a normal ward or even at home.
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PMID:[Difficult weaning]. 1704 78

Advanced age, smoking habit, obesity or malnutrition, the coexistence of hypercapnia, bronchospasm or bronchial hypersecretion, the lack of pre-operative preparation and/or a prolonged duration of anaesthesia can negatively influence respiratory function in patients undergoing abdominal or thoracic surgery. Spirometric testing of pulmonary function is recommended in patients with a history of tobacco use or dyspnoea who are considered for cardiac or upper abdominal surgery and for all patients who are candidated for lung resection. Spirometry can provide cut-off values of acceptable risk in patients that are candidated for abdominal and thoracic surgery. At-risk patients having resective lung surgery should undergo a split lung function study with quantitative lung scanning or computed tomography in order to estimate the function of residual parenchyma after surgery. In patients with borderline estimated values, a cardiopulmonary exercise test is useful to further stratify surgical risk.(www.actabiomedica.it)
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PMID:Respiratory effects of surgery and pulmonary function testing in the preoperative evaluation. 1717 84

Patients with obesity hypoventilation syndrome (OHS) have a lower quality of life, more healthcare expenses, a greater risk of pulmonary hypertension, and a higher mortality compared to eucapnic patients with obstructive sleep apnea (OSA). Despite significant morbidity and mortality associated with OHS, it is often unrecognized and treatment is frequently delayed. The objective of this observational study was to determine the prevalence of OHS in patients with OSA seen at the sleep disorders clinic of a large public urban hospital serving predominantly minority population and to identify clinical--not mechanistic--predictors that should prompt clinicians to measure arterial blood gases. In the first stage, we randomly selected 180 patients referred to our sleep disorders clinic between 2000 and 2004 for suspicion of OSA. From this retrospective random sample we calculated the prevalence of OHS in patients with OSA and identified independent clinical predictors using logistic regression. In the second stage, we prospectively validated these predictors in a sample of 410 consecutive patients referred to the sleep disorders clinic for suspicion of OSA between 2005 and 2006. The prevalence of OHS in patients with OSA was 30% in the retrospective random sample and 20% in the prospective sample. Three variables independently predicted OHS in both samples: serum bicarbonate level (p < 0.001), apnea-hypopnea index (p = 0.006), and lowest oxygen saturation during sleep (p < 0.001). Due to the serious morbidity associated with OHS, we selected a highly sensitive threshold of serum bicarbonate level. A threshold of 27 mEq/l had a sensitivity of 92% and a specificity of 50%. Only 3% of patients with a serum bicarbonate level <27 mEq/l had hypercapnia compared to 50% with a serum bicarbonate > or =27 mEq/l. In conclusion, OHS is common in severe OSA. A normal serum bicarbonate level excludes hypercapnia and an elevated serum bicarbonate level should prompt clinicians to measure arterial blood gases.
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PMID:Obesity hypoventilation syndrome: prevalence and predictors in patients with obstructive sleep apnea. 1765 82


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