Improvement of factor VII clotting activity following long-term NCPAP treatment in obstructive sleep apnoea syndrome.
Obstructive sleep apnoea syndrome (OSAS) is a very common disorder. Patients with OSAS are at an increased risk for cardiovascular events. It has also been reported that a 25% rise in factor VII clotting activity (FVIIc) is associated with a 55% increase in ischaemic heart disease death during the first 5 years. We examined the effects of nasal continuous positive airway pressure (NCPAP) treatment on FVIIc in patients with OSAS. FVIIc was investigated prospectively in 15 patients with OSAS before (mean +/- SEM apnoea and hypopnoea index (AHI) 61.5 +/- 4.2 and after (AHI 3.0 +/- 0.9) NCPAP treatment for immediate relief, at 1 month after treatment and at over 6 months. FVIIc levels gradually decreased after NCPAP treatment. After 6 months of NCPAP treatment, FVIIc levels had decreased significantly (before 141.1 +/- 11.7% vs. after 6 months 110.7 +/- 6.2%; p < 0.01). Six of the seven patients whose FVIIc levels were over 140% before the NCPAP treatment had FVIIc levels below 130% after 6 months or 1 year of NCPAP treatment. This decrease in FVIIc after long-term NCPAP treatment could improve mortality in OSAS patients. If patients, especially obese ones, present with high FVIIc of unknown origin, it would be prudent to check for OSAS. (+info)
Renal and hemodynamic effects of losartan in conscious dogs during controlled mechanical ventilation.
In 12 conscious dogs, we investigated whether the angiotensin II-receptor antagonist losartan increases renal sodium excretion and urine volume during controlled mechanical ventilation (CMV) with positive end-expiratory pressure. In four experimental protocols, the dogs were extracellular volume (ECV) expanded (electrolyte solution, 0.5 ml. kg-1. min-1 iv) or not and received losartan (100 micrograms. kg-1. min-1 iv) or not. They breathed spontaneously during the 1st and 4th hour and received CMV with positive end-expiratory pressure (mean airway pressure 20 cmH2O) during the 2nd and 3rd hours. In the expansion group, dogs with losartan excreted approximately 18% more sodium (69 +/- 7 vs. 38 +/- 5 micromol. min-1. kg-1) and 15% more urine during the 2 h of CMV because of a higher glomerular filtration rate (5.3 +/- 0.3 vs. 4.5 +/- 0.2 ml. min-1. kg-1) and the tubular effects of losartan. In the group without expansion, sodium excretion (2.0 +/- 0.6 vs. 2.6 +/- 1.0 micromol. min-1. kg-1) and glomerular filtration rate (3.8 +/- 0.3 vs. 3.8 +/- 0.4 ml. min-1. kg-1) did not change, and urine volume decreased similarly in both groups during CMV. Plasma vasopressin and aldosterone increased in both groups, and plasma renin activity increased from 4.9 +/- 0.7 to 7.8 +/- 1.3 ng ANG I. ml-1. h-1 during CMV in nonexpanded dogs without losartan. Mean arterial pressure decreased by 10 mmHg in nonexpanded dogs with losartan. In conclusion, losartan increases sodium excretion and urine volume during CMV if the ECV is expanded. If the ECV is not expanded, a decrease in mean arterial blood pressure and/or an increase in aldosterone and vasopressin during CMV attenuates the renal effects of losartan. (+info)
Cognitive function and treatment of obstructive sleep apnea syndrome.
Among patients with obstructive sleep apnea syndrome (OSAS), impairment of cognitive function, i.e. deficits in memory, attention, and visuconstructive abilities are common. We applied different forms of treatment for patients with newly diagnosed OSAS in a randomized study with a one-year follow-up. Patients with BMI > 40 kg/m2 were excluded. After the initial diagnostic work-up, male patients were considered to be candidates for either nasal continuous airway pressure (nCPAP) (27 patients) or surgical treatment (uvulopalatopharyngoplasty with or without mandibular osteotomy) (23 patients). Within the groups, the patients were then randomized to active treatment (nCPAP/surgery) or to conservative management. Cognitive function and severity of OSAS were assessed prior to treatment and 3 and 12 months later. At 12 months, all patients on nCPAP had a normal ODI4 index (< 10), and were significantly less somnolent than their controls; 3/11 of the surgically treated patients had a normal ODI4 index. Daytime somnolence was significantly less severe in the surgically treated patients than in their controls. Cognitive function did not correlate importantly with daytime sleepiness or severity of OSAS; the best Pearson pairwise correlation coefficient was between ODI4 and the Bourdon-Wiersma (r = 0.36). Success in treatment of OSAS did not affect neuropsychological outcome. We concluded that the standard cognitive test battery is insufficiently sensitive to identify positive changes in patients with OSAS, especially among those with a high level of overall mental functioning. (+info)
Survey of non-invasive ventilation (NIPPV) in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) in the UK.
BACKGROUND: Non-invasive positive pressure ventilation (NIPPV) has been shown to be beneficial in the treatment of acute exacerbations of chronic obstructive pulmonary disease (COPD) complicated by respiratory failure. A survey was undertaken to assess the availability of NIPPV for the treatment of acute exacerbations of COPD and to determine how NIPPV is delivered in hospitals in the UK. METHODS: A questionnaire was sent to consultants with an interest in respiratory medicine from 268 of the hospitals found in the BTS directory. The questionnaire enquired about the hospital as well as the availability of NIPPV in the hospital. If NIPPV was available in the hospital, details of implementation, staffing and funding were determined. RESULTS: Replies to the questionnaire were received from 98.5% of consultants. NIPPV was available in 48% of hospitals, these hospitals tending to serve larger populations and to have more respiratory physicians than the hospitals where NIPPV was not available. There was considerable regional variation in the availability of NIPPV. In hospitals where NIPPV was not available the reason(s) were lack of consultant training in 53%, lack of other staff training in 63%, financial in 63%, and doubt about the benefit of NIPPV in 15% of cases. In those hospitals where NIPPV was available, clinical practice varied greatly: 68% of centres treated fewer than 20 patients a year with this form of treatment and 9% treated more than 60 patients a year. Although NIPPV was paid for completely from the trust equipment budget in 46 hospitals (41%), other money such as research or charitable funds were used at least partially in the other hospitals and NIPPV was financed solely from research or charitable funds in 41 hospitals (37%). CONCLUSIONS: Equipment for NIPPV is available in less than half of the acute hospitals in the UK. In those in which it is available it is generally underused. Lack of training and problems with funding are generally given for the failure to introduce NIPPV. (+info)
Efficacy of nasal continuous positive airway pressure therapy in chronic heart failure: importance of underlying cardiac rhythm.
BACKGROUND: Some previous reports have indicated beneficial cardiac effects of nasal continuous positive airway pressure (NCPAP) in patients with severe congestive heart failure (CHF), but others have reported deleterious cardiac effects, particularly among patients in atrial fibrillation (AF). The aim of this study was to determine if differences in cardiac rhythm influence the acute cardiac response to NCPAP. METHODS: Eleven consecutive patients with CHF were recruited, six in atrial fibrillation (AF) and five with sinus rhythm (SR). Cardiac index was measured during awake NCPAP application by the thermodilution technique during cardiac catheterisation. NCPAP was applied in a randomised sequence at pressures of 0, 5, and 10 cm H2O with three 30 minute applications separated by 20 minute recovery periods without NCPAP. RESULTS: Significant differences were found between the AF and SR groups for cardiac index responses to NCPAP (p = 0.004, ANOVA) with a fall in cardiac index in the AF group (p = 0.02) and a trend towards an increase in the SR group (p = 0.10). Similar differences were seen between the groups in stroke volume index responses but not in heart rate responses. Changes in systemic vascular resistance were also significantly different between the two groups (p < 0.005, ANOVA), rising in the AF group but falling in the SR group. CONCLUSIONS: These data indicate an important effect of underlying cardiac rhythm on the awake haemodynamic effects of NCPAP in patients with CHF. (+info)
Cardiopulmonary resuscitation: effect of CPAP on gas exchange during chest compressions.
BACKGROUND: Conventional cardiopulmonary resuscitation (CPR) includes 80-100/min precordial compressions with intermittent positive pressure ventilation (IPPV) after every fifth compression. To prevent gastric insufflation, chest compressions are held during IPPV if the patient is not intubated. Elimination of IPPV would simplify CPR and might offer physiologic advantages, but compression-induced ventilation without IPPV has been shown to result in hypercapnia. The authors hypothesized that application of continuous positive airway pressure (CPAP) might increase CO2 elimination during chest compressions. METHODS: After appropriate instrumentation and measurement of baseline data, ventricular fibrillation was induced in 18 pigs. Conventional CPR was performed as a control (CPR(C)) for 5 min. Pauses were then discontinued, and animals were assigned randomly to receive alternate trials of uninterrupted chest compressions at a rate of 80/min without IPPV, either at atmospheric airway pressure (CPR(ATM)) or with CPAP (CPR(CPAP)). CPAP was adjusted to produce a minute ventilation of 75% of the animal's baseline ventilation. Data were summarized as mean +/- SD and compared with Student t test for paired observations. RESULTS: During CPR without IPPV, CPAP decreased PaCO2 (55+/-28 vs. 100+/-16 mmHg) and increased SaO2 (0.86+/-0.19 vs. 0.50+/-0.18%; P < 0.001). CPAP also increased arteriovenous oxygen content difference (10.7+/-3.1 vs. 5.5+/-2.3 ml/dl blood) and CO2 elimination (120+/-20 vs. 12+/-20 ml/min; P < 0.01). Differences between CPR(CPAP) and CPR(ATM) in aortic blood pressure, cardiac output, and stroke volume were not significant. CONCLUSIONS: Mechanical ventilation may not be necessary during CPR as long as CPAP is applied. Discontinuation of IPPV will simplify CPR and may offer physiologic advantage. (+info)
Nasopharyngeal symptoms in patients with obstructive sleep apnea syndrome. Effect of nasal CPAP treatment.
BACKGROUND: Nasal side effects are often reported during nasal continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea syndrome (OSAS) and may make the use of nasal CPAP difficult. OBJECTIVE: The aim of this study was to evaluate the effect of nasal CPAP on nasopharyngeal symptoms in OSAS patients. METHODS: The frequency and severity of nasopharyngeal symptoms and signs were prospectively evaluated in 49 consecutive OSAS patients (37 men, 12 women, mean (SD) age 54 (7) years, body mass index 35 (6) kg/m2) immediately before and after 6 months' treatment with nasal CPAP. RESULTS: Nasopharyngeal symptoms were common already before starting nasal CPAP: 74% of patients reported dryness, 53% sneezing, 51% mucus in the throat, 45% blocked nose, and 37% rhinorrhea. During nasal CPAP treatment, severity and frequency of sneezing (75%) and rhinorrhea (57%) increased. This increase was related to the season when nasal CPAP was applied, and was more profound in winter than in summer. Mild abnormalities on rhinoscopy and paranasal sinus X-rays were common both at baseline and at follow-up with no significant change during treatment. CONCLUSIONS: Nasopharyngeal problems were found to be frequent in patients with OSAS before nasal CPAP treatment, and tended to increase during the treatment. (+info)
Hemodynamic effects of bilevel nasal positive airway pressure ventilation in patients with heart failure.
AIMS: Benefits of nasal continuous positive airway pressure (CPAP) in patients presenting with chronic heart failure (CHF) are controversial. The purpose of this study was to compare the hemodynamic effects of CPAP and bilevel positive airway pressure (BiPAP) in patients with or without CHF. METHODS AND RESULTS: Twenty patients with CHF and 7 with normal left ventricular function underwent cardiac catheterization. Measurements were made before and after three 20-min periods of BiPAP: expiratory positive airway pressure (EPAP) = 8 cm H2O and inspiratory positive airway pressure (IPAP) = 12 cm H2O, EPAP = 10 cm H2O and IPAP = 15 cm H2O, and CPAP = EPAP = IPAP = 10 cm H2O administered in random order. Positive pressure ventilation decreased cardiac output (CO) and stroke volume. No change was observed in either pulmonary or systemic arterial pressure. There was no difference in the hemodynamic effects of the three ventilation settings. Only mean pulmonary wedge pressure (MPWP) and heart rate were lower with CPAP than with BiPAP. CO decreased only in patients with low MPWP (+info)