Effect of varying the pressurisation rate during noninvasive pressure support ventilation.
(17/875)
The aim of the study was to assess the effects of varying the pressurisation rate during noninvasive pressure support ventilation on patients' breathing pattern, inspiratory effort, arterial blood gases, tolerance to ventilation and amount of air leakage. A total of 15 chronic obstructive pulmonary disease patients recovering from an acute episode of hypercapnic acute respiratory failure were studied during four randomised trials with different levels of pressurisation rate. No significant changes were observed in breathing pattern and arterial blood gases between the different runs. The pressure time product of the diaphragm, an estimate of its metabolic consumption, was significantly lower with all pressurisation rates than with spontaneous breathing, but was significantly lowest with the fastest rate. However, air leak, assessed by the ratio between expired and inspired tidal volumes, increased and the patients' tolerance of ventilation, measured using a standardised scale, was significantly poorer with the fastest pressurisation rate. In chronic obstructive pulmonary disease patients recovering from an episode of acute hypercapnic respiratory failure and ventilated with noninvasive pressure support ventilation, different pressurisation rates resulted in different reductions in the pressure time product of the diaphragm; this reduction was greater with the fastest rate, but was accompanied by significant air leaks and poor tolerance. (+info)
Randomised controlled comparison of continuous positive airways pressure, bilevel non-invasive ventilation, and standard treatment in emergency department patients with acute cardiogenic pulmonary oedema.
(18/875)
BACKGROUND: Continuous positive airways pressure (CPAP) and bilevel non-invasive ventilation may have beneficial effects in the treatment of patients with acute cardiogenic pulmonary oedema. The efficacy of both treatments was assessed in the UK emergency department setting, in a randomised comparison with standard oxygen therapy. METHODS: Sixty patients presenting with acidotic (pH<7.35) acute, cardiogenic pulmonary oedema, were randomly assigned conventional oxygen therapy, CPAP (10 cm H(2)O), or bilevel ventilation (IPAP 15 cm H(2)O, EPAP 5 cm H(2)O) provided by a standard ventilator through a face mask. The main end points were treatment success at two hours and in-hospital mortality. Analyses were by intention to treat. RESULTS: Treatment success (defined as all of respiratory rate<23 bpm, oxygen saturation of>90%, and arterial blood pH>7.35 (that is, reversal of acidosis), at the end of the two hour study period) occurred in three (15%) patients in the control group, seven (35%) in the CPAP group, and nine (45%) in the bilevel group (p = 0.116). Fourteen (70%) of the control group patients survived to hospital discharge, compared with 20 (100%) in the CPAP group and 15 (75%) in the bilevel group (p = 0.029; Fisher's test). CONCLUSIONS: In this study, patients presenting with acute cardiogenic pulmonary oedema and acidosis, were more likely to survive to hospital discharge if treated with CPAP, rather than with bilevel ventilation or with conventional oxygen therapy. There was no relation between in hospital survival and early physiological changes. Survival rates were similar to other studies despite a low rate of endotracheal intubation. (+info)
Increased prevalence of perennial allergic rhinitis in patients with obstructive sleep apnea.
(19/875)
BACKGROUND: Impaired nasal breathing is a risk factor for obstructive sleep apnea syndrome (OSAS). OBJECTIVES: The aim of this study was to determine whether atopy to perennial allergens and existence of perennial allergic rhinitis was a risk factor for OSAS. METHODS: In a case-control study, we compared the proportions of OSAS patients with atopy to perennial allergens and perennial allergic rhinitis to the proportions in patients with chronic obstructive pulmonary disease (COPD). Seventy-two OSAS patients (mean age 60.7 years; 79.4% male) and 44 COPD patients (mean age 63.6 years; 88.6% male) were selected from a hospital outpatients' clinic in Switzerland. All patients completed a respiratory symptom questionnaire, performed spirometry and had a skin prick test for atopy. RESULTS: OSAS patients were significantly heavier than COPD patients (BMI 32.4 +/- (SD) 6.6 vs. 29.2 +/- 6.6 kg/m2, p = 0.04) and had a better lung function than COPD patients (FEV1% predicted 91.3 +/- 19.2 vs. 51.6 +/- 18.9%, p < 0.001). Patients with OSAS were more likely to be sensitized to perennial allergens such as house dust mite (23.6 vs. 4.5%, p = 0.009) and dog (18 vs. 4.5%, p = 0.04) than the COPD patients. Perennial allergic rhinitis (having nose problems [nasal obstruction and/or runny nose and/or sneezing] all year and being atopic to at least one perennial allergen) was reported in 11% of OSAS patients but in only 2.3% of COPD patients (p = 0.15). CONCLUSION: We conclude that subjects with OSAS may have an increased risk of being allergic to perennial allergens and suffer from perennial rhinitis. Awareness of this risk may have important consideration in the clinical situation. (+info)
Sleep-disordered breathing in patients with idiopathic cardiomyopathy.
(20/875)
BACKGROUND: Sleep-disordered breathing may adversely affect heart function, and thereby contribute to the progression of heart failure. A study was undertaken in patients with idiopathic cardiomyopathy to document the characteristics of sleep-disordered breathing. METHODS AND RESULTS: Thirty-five patients with a diagnosis of idiopathic cardiomyopathy, comprising 20 patients with dilated cardiomyopathy (DCM) and 15 patients with hypertrophic cardiomyopathy (HCM), underwent overnight polysomnography. Of these 35, 16 (80%) of the DCM patients and 7 (47%) of the HCM patients had sleep-disordered breathing. Central sleep apnea-hypopnea syndrome (CSAHS) was seen in 10 DCM patients, but not in the HCM patients, and obstructive sleep apnea-hypopnea syndrome (OSAHS) was seen in 6 DCM patients and 7 HCM patients. CSAHS was seen in DCM patients with a low left ventricular ejection fraction. HCM patients with OSAHS had a significantly greater body mass index (BMI) than those without OSAHS and CSAHS (27.6 +/- 3.8 vs 22.0 +/- 4.0 kg/m2, p<0.05). DCM patients with OSAHS had a larger BMI than those with CSAHS (29.3 +/- 5.8 vs 24.2 +/- 4.0 kg/m2, p<0.05) and those without OSAHS and CSAHS (29.3 +/- 5.8 vs 21.3 +/- 3.1 kg/m2, p<0.05). CONCLUSIONS: Sleep-disordered breathing is common in patients with idiopathic cardiomyopathy; half of DCM patients had CSAHS, which was closely associated with obesity. (+info)
Effects of obesity upon genioglossus structure and function in obstructive sleep apnoea.
(21/875)
Obesity is a common feature of the obstructive sleep apnoea syndrome. It can influence the structure and function of skeletal muscles. However, its effects upon the upper airway muscles have not been explored directly. This study assessed the structure and function of the genioglossus in patients with obstructive sleep apnoea syndrome and in healthy subjects (with and without obesity, defined by a body mass index > 30 kg x m(-2)). Further, to investigate the effects of continuous positive airway pressure (CPAP) treatment, patients with obstructive sleep apnoea syndrome after at least 1 yr under CPAP were also studied. The study found that obese and nonobese patients showed different in vitro geniglossus endurance properties. In obese patients, geniglossus endurance was indistinguishable from normal while, nonobese patients, at diagnosis, showed increased genioglossus fatigability; this was not observed in patients treated with CPAP. By contrast, patients with obstructive sleep apnoea syndrome showed at diagnosis a higher percentage of type II fibres than controls and patients under CPAP treatment independently of obesity. This difference is mainly due to a predominance of subtype IIb fibre. This difference was not observed in the group of patients treated with CPAP. Genioglossus twitch force was normal in all patients. These results suggest that different pathogenic mechanisms may underlie the development of obstructive sleep apnoea syndrome in obese and nonobese patients. This observation may have potential clinical implications. (+info)
Influence of treatment on leptin levels in patients with obstructive sleep apnoea.
(22/875)
Obstructive sleep apnoea syndrome (OSAS) is a common disorder in obesity. Leptin, an adipocyte-derived signalling factor, plays an important role in metabolic control. There is growing evidence that leptin regulation is altered in OSAS. Therefore, the aim of this study was to test the hypothesis that effective treatment will influence leptin levels in OSAS patients. Serum leptin levels were determined in 86 consecutive patients (aged 57.5 +/- 11.0 yrs) with polysomnographically verified OSAS. In addition, leptin levels were reassessed and treatment efficacy was evaluated by polysomnography after 6 months of therapy. Patients were treated with continuous or bilevel positive airway pressure, a mandibular advancement device or conservatively, depending on the clinical symptoms. Mean serum leptin levels did not change with treatment in the whole study group (7.3 +/- 5.0 versus 7.5 +/- 4.8 ng.mL-1), however, leptin levels decreased in effectively treated patients (8.5 +/- 5.0 versus 7.4 +/- 5.1 ng.mL-1) while they increased in ineffectively treated patients (5.0 +/- 4.0 versus 7.7 +/- 4.1 ng.mL-1). Furthermore, not only was there a significant and independent correlation between the change in leptin levels with treatment and the change in body mass index, but also with the change in apnoea/hypopnoea index. Effective treatment of sleep-disordered breathing may have significant effects on leptin levels in obstructive sleep apnoea syndrome patients. Changes in leptin levels are related to changes in apnoea/hypopnoea index in obstructive sleep apnoea syndrome patients. (+info)
Stroke and blood pressure variability.
(23/875)
Sleep apnoea is associated with increased cardiovascular risk. Sleep apnoea is common after stroke and associated with increased blood pressure variability as described by Turkington and co-workers in this issue of Clinical Science. Both sleep apnoea and blood pressure variability confer a poor prognosis after stroke and are potentially treatable. Many studies of CPAP (continuous positive airway pressure) demonstrate decreases in cardiovascular risk markers in other patient groups. Although difficult to apply in these patients in the short term, CPAP has some potential benefits in medium-term rehabilitation and secondary prevention following stroke, which warrants further study. (+info)
The effect of continuous positive airway pressure treatment on insulin sensitivity in patients with obstructive sleep apnoea syndrome and type 2 diabetes.
(24/875)
BACKGROUND: The obstructive sleep apnoea syndrome (OSA) is a frequent condition, as well as type 2 diabetes mellitus. Both diseases are characterized by insulin resistance. OBJECTIVES: The aim of this study was to establish whether OSA is an independent risk factor for increased insulin resistance in diabetics. For this purpose, we tested the hypothesis that the insulin sensitivity in patients with type 2 diabetes and OSA can be improved by 2 days or 3 months of continuous positive airway pressure (CPAP) treatment. METHODS: In 9 obese patients with type 2 diabetes and OSA [apnoea/hypopnoea index 43.1 +/- 21.3; body mass index (BMI) 37.3 +/- 5.6 kg/m2] and good glycaemic control on oral antidiabetics or on diet alone (HbA1c 6.4 +/- 0.7%), the insulin sensitivity index (ISI) was established by euglycaemic hyperinsulinaemic clamp tests at baseline, after 2 days and after 3 months of effective CPAP treatment. RESULTS: ISI was unchanged after 2 days of CPAP treatment, but was significantly improved after 3 months (4.38 +/- 2.94 vs. 2.74 +/- 2.25 at baseline; p = 0.021), without any significant changes in BMI. Glycaemic control was unaffected after 3 months (HbA1c 6.3 +/- 0.6%; not significant). Fasting leptin levels showed no significant changes. CONCLUSIONS: These results indicate that OSA itself is an independent risk factor for insulin resistance. This effect may be explained by the elevated sympathetic activity in OSA. (+info)