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

One hundred and sixty-one ASA physical status I-III patients undergoing elective surgery were evaluated using nasal catheters versus 40 per cent O2 venturi masks. Twenty-one per cent of the patients arrived in the recovery room with hypoxia as measured with a pulse oximeter (SaO2 less than 90 per cent). Fifteen minutes later all patients who arrived hypoxic were well oxygenated on their chosen oxygen therapy. Only one patient that arrived normoxic became hypoxic using a nasal catheter 15 minutes later. There was no statistical difference between patients given 40 per cent O2 by mask versus patients given oxygen by nasal catheter. The mean SaO2 for the group given 40 per cent O2 at 15 minutes was 96.7 +/- 2.15 per cent versus 96.6 +/- 2.48 per cent for nasal catheters. Nasal catheters are as effective as 40 per cent O2 masks for treating hypoxia in the recovery room. Obesity and age were statistically significant risk factors in the patients that arrived hypoxic. Patients were 47.4 +/- 15.6 years in the hypoxic group versus 38.3 +/- 15.6 years in the non-hypoxic group (p less than 0.001). Patients having an endotracheal tube with intermittent positive pressure ventilation or having a premedication were more apt to be hypoxic on arrival. These last two factors were closely associated and may reflect bias. The patient's gender, history of smoking, presence of obstructive lung disease, not including asthma, location of incision, or type of anaesthetic were not statistically significant risk factors.
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PMID:Recovery room oxygenation: a comparison of nasal catheters and 40 per cent oxygen masks. 264 49

Sustained elevations of plasma glucose and insulin concentrations follow intense (80% maximum oxygen uptake) exercise performed in the postabsorptive state. To provide insights into possible mechanisms and influence of obesity, 8 lean and 12 obese subjects [106 +/- 11% (SD) and 193 +/- 31% of reference table weight, respectively] eating previously isocaloric diets were exercised to exhaustion (7 +/- 3 min) on a cycle ergometer, then followed for 60 min of recovery. The obese subjects at rest had slightly increased plasma glucose and insulin and elevated blood glycerol concentrations. Both lean and obese subjects had little or no changes in plasma glucose or insulin during exercise, but the increases during the recovery period were greater and/or sustained longer in the obese. Such results raise the possibility of transient hepatic insulin resistance after exercise and are possibly relevant to restoration of depleted muscle glycogen. Both groups had a marked fall in plasma FFA during exercise; the reduction was sustained in the lean but not in the obese subjects. Blood glycerol increased during the recovery period to higher values in the obese than in the lean subjects. Plasma norepinephrine increased about 4-fold in both groups, returning promptly to preexercise values. In contrast, the exercise-induced increment in plasma epinephrine [values at exhaustion, 933 +/- 548 vs. 1970 +/- 787 pmol/L; P less than 0.005] was markedly attenuated in the obese subjects. Thus, the obese subjects had exercise-induced changes in glucose and inulin metabolism consistent with greater postexercise insulin resistance, despite an impaired plasma epinephrine response to intense exercise.
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PMID:Metabolic responses to intense exercise in lean and obese subjects. 264 9

Non-apnoeic oxygen desaturation related to rapid eye movement (REM) sleep in a patient with hypothyroidism, obesity, respiratory failure, and cardiac failure was improved by treatment with nasal continuous positive airway pressure of 10 cm H2O.
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PMID:Non-apnoeic REM sleep induced nocturnal oxygen desaturation treated by nasal continuous positive airway pressure. 266 26

Genetically obese-hyperglycemic (ob/ob) mice are hypothyroid, hyperinsulinemic, and insulin resistant. Because muscle plays an important role in glucose homeostasis, the role of triiodothyronine (T3) in regulation of insulin-sensitive glucose utilization by muscles of obese mice was examined. Four doses of T3, 5.0, 12.5, 25.0, and 50.0 micrograms/100 g body weight were injected, i.p., into obese and nonobese mice daily from 3 weeks until 6 weeks of age. Food consumption and body weight were decreased at lower doses of T3 and increased at higher doses of T3 in both obese and nonobese mice. By 6 weeks of age all doses of T3 treatment increased oxygen consumption in both genotypes. At 6 weeks of age, the diaphragms from the saline-injected nonobese mice had greater in-vitro insulin-stimulated glucose utilization than muscles from the saline-injected obese mice. Both anaerobic and aerobic glucose oxidation were increased by T3 treatment, but the obese had greater increases than those observed in muscles from nonobese mice. Muscles from obese mice increased insulin-stimulated glucose utilization by T3 treatment to that of the nonobese level, whereas there was no change in insulin-stimulated glucose utilization of nonobese mice. Muscle glycogen synthesis in obese and nonobese mice was decreased with very high T3 doses. A higher dose of T3 was required to increase glucose utilization in the obese muscles than in the nonobese muscles. The results suggest that a functional hypothyroidism or T3 resistance may be an early part of this particular obesity syndrome.
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PMID:Effect of triiodothyronine on glucose utilization in diaphragm of obese (ob/ob) mice. 270 91

We studied the influence of lung volumes on apnoea-induced desaturation in ten subjects with sleep apnoea syndrome. Lung volumes were measured by helium dilution in the sitting and supine position and closing volume with the single-breath nitrogen washout test. To characterize the severity of apnoea-induced desaturations, we determined a desaturation curve for each patient. This curve was obtained by plotting the fall in arterial oxygen saturation (SaO2) reached at the end of each apnoea against the apnoea duration. From this curve we selected two indices: 1) the SaO2 fall following 30 s of obstructive apnoea (delta SaO2 30); and 2) the desaturation surface between 10-30 s of obstructive apnoea (DS 10-30). Both the delta SaO2 30 and the DS 10-30 were significantly correlated with the expiratory reserve volume (ERV), measured in the sitting (r = 0.77 and 0.65, respectively; p less than 0.05) and the supine positions (r = 0.96 and 0.87; p less than 0.005). A strong correlation was also observed with the difference between the supine ERV and the seated closing volume CV) (r = 0.99 with delta SaO2 30 and 0.89 with DS 10-30; p less than 0.005). Obesity influenced sitting and supine ERV values. We conclude that, among lung volumes, supine ERV and supine ERV-seated CV are the best indicators of the severity of apnoea-induced desaturation.
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PMID:Role of lung volumes in sleep apnoea-related oxygen desaturation. 270

In order to obtain adequate normal values for arterial blood gas values, the effect of aging and activity was investigated by cross-sectional selection in an in-patient population of 108 patients aged between 20 and 90 years. The patients were free of pulmonary, cardiac and metabolic disease. Smoking and obesity were tolerated up to specified limits. Arterial blood was obtained during standardised resting and active states. The results show a clinically important and highly significant (p less than 0.001) decline of the oxygen tension (PaO2) with age and also a considerable effect of minor activity (p less than 0.01) on blood gas values. However, the relationship of both oxygen tension and oxygen saturation with age is not a linear function as suggested in previous studies. For the interpretation of arterial oxygen tension values or to define hypoxaemia, only normal values related to age and activity should be used. In the elderly, low levels of PaO2 are encountered regularly. Determination of the oxygen saturation may be helpful, especially in differentiating between a normal and a pathological state.
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PMID:[The effect of age and activity on arterial oxygen pressure and arterial oxygen saturation in hospitalized patients]. 273 88

During breath holding, correlations have been demonstrated between the rate of fall of arterial oxyhemoglobin saturation (dSaO2/dt) and the following: thoracic gas volume at apnea onset, resting oxygen consumption, preapneic arterial oxyhemoglobin saturation (SaO2) and obesity. A key factor influencing dSaO2/dt is mixed venous oxyhemoglobin saturation (SvO2) as recently demonstrated in an animal model of obstructive apnea. The purpose of the present study was to see if dSaO2/dt was related to SvO2 during sleep in a group of subjects with severe obstructive sleep apnea (OSA) and varying levels of SvO2. Eight OSA subjects were studied during sleep with indwelling arterial and central venous catheters. Continuous SaO2 was measured by ear oximetry while continuous SvO2 was measured through the fiberoptic bundle of a Shaw Opticath catheter. Thirty percent or more of all obstructive apneas were scored for duration, preapneic SaO2, SvO2 and dSaO2/dt. Least squares regression was used to examine the relationship between dSaO2/dt and other measured variables. The dSaO2/dt showed a consistent negative correlation with preapneic SvO2 and was not related to duration. Mean dSaO2/dt during sleep correlated to some degree with the degree of gas exchange (Qva/Qt) abnormality prior to sleep. It is concluded that in humans, SvO2 plays a substantial role in determining dSaO2/dt. Potentially, the presence of gas exchange abnormalities (eg, found in intrinsic lung disease) causing hypoxemia and low SvO2 may steepen dSaO2/dt, lowering the nadir level of apneic desaturation for the same duration of apnea found in a patient with more normal gas exchange.
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PMID:The rate of fall of arterial oxyhemoglobin saturation in obstructive sleep apnea. 279 63

To investigate the potential role of skeletal muscle metabolism in the determination of whole body energy balance, the rate of oxygen consumption was measured in soleus muscles isolated from mice of differing age, sex, strain (thin and obese), thyroid and nutritional status. As expected, T3-induced hyperthyroidism resulted in an increase in the intrinsic rate of energy utilization by the muscles; qualitatively similar changes were noted in both younger animals and mice induced to increase their energy intake by sucrose-overfeeding. In contrast, soleus muscle oxygen consumption was significantly reduced in genetically obese NZO mice. Parallel changes in the activity of the Na-K pump were observed in all groups of animals, with a good correlation (r greater than 0.6, P less than 0.01) noted between these two independently measured aspects of muscle metabolism. The results suggest that the intrinsic metabolic rate of the skeletal muscle mass plays an important role in the control of overall energy balance, with changes in this rate being potentially partly responsible for the altered energetic efficiency of genetic obesity and adaptive thermogenesis models. In addition, measurement of the activity of the Na-K-pump may provide a convenient marker for such observed changes in energy utilization.
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PMID:Skeletal muscle metabolism: effect of age, obesity, thyroid and nutritional status. 279 63

Brown adipose tissue (BAT) thermogenesis was assessed by measuring mitochondrial guanosine diphosphate (GDP) binding, cytochrome oxidase activity and oxygen consumption in ovariectomized (OVX) and sham-operated rats. The food intake and body weight of OVX rats increased more than those of controls and OVX rats became obese. Mitochondrial GDP binding, as an indicator of thermogenic activity, cytochrome oxidase activity, as a marker of mitochondrial abundance, and mitochondrial respiration of BAT in OVX rats were significantly reduced compared with those in controls. And, also, even when OVX rats were restricted in food intake (pair-gained) to produce comparable changes in body weight with sham-controls, or matched in food intake (pair-fed) with sham-controls, these parameters in both pair-gained and pair-fed OVX groups were decreased markedly compared to those in sham-controls. As expected, body weight in pair-fed OVX rats increased significantly more than that in sham-controls. In response to cold exposure, these parameters of OVX rats increased as much as those of controls did. These results suggest that reduced brown adipose tissue thermogenesis might be one of the important factors that are responsible for the development of obesity after OVX.
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PMID:Reduced brown adipose tissue thermogenesis of obese rats after ovariectomy. 285 Sep 6

Guidelines for the medical therapy of obstructive sleep apnea are difficult to define precisely. While some elegant investigations have been completed, most study populations have been small. Also, the long-term effects of most forms of therapy are not known. Some patients will respond to a given form of therapy or combination of therapies while others will not. In most instances the responders cannot be recognized prior to the institution of therapy and a cycle of trial and error ensues. One of the best nonsurgical approaches appears to be weight loss, albeit unsuccessful in most cases. Almost all experts would agree, however, that in nonemergent situations weight loss should be strongly suggested. Nasal CPAP appears to be the single most promising device. Protriptyline may have a role, although in our opinion its true efficacy remains to be determined. Oxygen will probably serve more an adjunctive role in therapy, and medroxyprogesterone appears to be beneficial only in the treatment of the obesity-hypoventilation syndrome. A reasonable approach to the medical treatment of the obstructive sleep apnea patient should include, first, by history, physical examination, and appropriate laboratory testing, elimination of anatomically correctable, pharmacologic, or endocrinologic causes of OSA. If apnea length, degree of desaturation, cardiac arrhythmias, or levels of hypersomnolence are so severe as to be potentially life threatening, immediate tracheostomy is suggested. In specialized centers, nasal CPAP would be used. In less severely affected patients, medical management, as discussed above, should begin. We believe that in view of the lack of controlled trials demonstrating which form of therapy is best, the clinician must recommend therapy on the basis of local clinical experience and patient acceptance. Of fundamental importance is the need for serial reevaluation so that the impact of therapeutic failure can be minimized.
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PMID:Medical therapy of obstructive sleep apnea. 286 88


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