Long-term effects nasal continuous positive airway pressure on daytime sleepiness, mood and traffic accidents in patients with obstructive sleep apnoea.
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To describe the long-term effects of nasal continuous positive airway pressure (CPAP) on the rate of traffic car accidents, excessive daytime sleepiness (EDS) and mood in patients with obstructive sleep apnoea syndrome (OSAS), we investigated the changes of these parameters before and after nasal CPAP treatment using a questionnaire. Seventy-five male patients who were diagnosed with severe OSAS by polysomnography were evaluated for driving competence, by looking at their driving history for 2 yr, for EDS by the Epwarth Sleepiness Scale (ESS) and for mood by the Self-related Depression Scale (SDS), and then underwent nasal CPAP treatment. After 2 yr of treatment, questionnaires inquiring about the patients' use of CPAP, their ESS, SDS and driving history during treatment were sent to the patients. A total of 47 patients (63%) responded to these questionnaires. Forty-six of the 47 responders had continued to use the nasal CPAP and completed the questionnaire. No traffic car accidents were observed among the 39 routine car users during treatment, while 13 of 39 patients (33%) had had car accidents before treatment. Although near-miss accidents had been reported by 32 of 39 patients (82%) before treatment, only four patients reported near-miss accidents during nasal CPAP treatment. The mean score of ESS was significantly (P<0.01) reduced in 46 patients after nasal CPAP. The mean score of SDS was also decreased (P<0.01) after nasal CPAP in 46 patients. Although 26 of 41 patients had been depressive on SDS before treatment, the mood was improved in 13 patients after nasal CPAP. These results suggest that long-term nasal CPAP treatment reduces the rate of traffic car accidents and improves the EDS and the mood in patients with OSAS. (+info)
Strategies for ventilatory support.
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Since the introduction of manual positive pressure ventilation during the Copenhagen polio epidemic of 1952, a range of mechanical devices and methods of ventilatory support have been developed to provide life-saving respiratory therapy to critically ill patients. In addition to the development of the equipment hardware to enable effective mechanical ventilation, there has been a gradual realisation that a single mode of ventilation is not universally applicable to all patients, individual pathologies, or to individual patients at various stages in the evolution of their pulmonary pathology. While mechanical ventilation can undoubtedly be life-saving, it can also cause lung damage as a result of its non-physiological method of promoting effective gas exchange. This iatrogenic problem is known as ventilator induced lung injury and, although it may be a problem in any patient requiring mechanical ventilation for any reason, is of particular importance to those patients requiring mechanical ventilation as a consequence of trauma. This chapter describes the range of ventilatory support techniques available, the problem of ventilator induced lung injury with specific reference to trauma patients and offers a strategy for ventilatory support in the trauma patient. (+info)
Effects of biphasic positive airway pressure in patients with chronic obstructive pulmonary disease.
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Biphasic positive airway pressure (BiPAP) is a ventilatory mode in which two pressure levels (higher (Phigh) and lower (Plow)) acting as continuous positive airway pressure (CPAP) alternate at preset time intervals. BiPAP combines pressure-controlled ventilation with unrestricted spontaneous breathing. BiPAP has not yet been evaluated in patients with chronic obstructive pulmonary disease (COPD). Therefore, the effects of BiPAP (15 cmH2O Phigh and 5 cmH2O Plow) pressure support (PS; 15 cmH2O and positive end-expiratory pressure (PEEP) 5 cmH2O) and CPAP (5 cmH2O) on respiratory mechanics in COPD patients were compared. Twenty-one COPD patients were supported in randomized order with BiPAP, PS and CPAP. Pressure-time product (PTP), work of breathing (WOB), change in oesophageal pressure (deltaPoes), mouth occlusion pressure (P0.1), intrinsic PEEP (PEEPi), tension time index (TTI), respiratory frequency, and tidal volume (VT) were measured. During BiPAP, the COPD patients showed a significantly higher PTP, WOB, deltaPoes, P0.1, TTI and PEEPi than during PS. Comparing the Plow phases of BiPAP and CPAP, the breaths during the Plow phases of BiPAP had a lower VT and a greater WOB and PTP due to a higher PEEPi than on CPAP alone. In conclusion, biphasic positive airway pressure carries the risk of increased work of breathing in spontaneously breathing chronic obstructive pulmonary disease patients. Pressure support is superior for reducing their respiratory muscle effort. (+info)
Effects of nasal continuous positive airway pressure on awake ventilatory responses to hypoxia and hypercapnia in patients with obstructive sleep apnea.
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This study was aimed to examine the short- and long-term effects of nasal continuous positive airway pressure (CPAP) on the chemosensitivity to hypoxia and hypercapnia in the patients with obstructive sleep apnea (OSA). Awake ventilatory responses to hypoxia and hypercapnia were examined in 28 patients (3 female) with moderate to severe OSA. All these tests were examined before and after 2 weeks of nasal CPAP. In 10 patients these tests were repeated after 3-6 months of nasal CPAP. All were also tested for spirometry and arterial blood gas analysis. Patients were middle-aged (48.9 +/- 9.9 years) and their mean apnea-hypopnea index was 58.3 +/- 20.4/hour. After 2 week of nasal CPAP, PaO2 significantly increased (77.7 +/- 11.8 vs. 84.6 +/- 9.8 mmHg) and PaCO2 significantly decreased (44.9 +/- 3.8 vs. 42.3 +/- 3.7 mmHg). The ventilatory response to hypoxia significantly decreased (0.80 +/- 0.51 vs. 0.61 +/- 0.51 liter/min/%) whereas the ventilatory response to hypercapnia significantly increased after 2 weeks (1.47 +/- 0.73 vs. 1.80 +/- 0.76 liter/min/mmHg). Similar findings were also observed after 3-6 months of nasal CPAP in 10 OSA patients. Nasal CPAP treatment can alter the ventilatory responses in patients with OSA. (+info)
Respiratory muscle activity in patients with COPD walking to exhaustion with and without pressure support.
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The function of the diaphragm and other respiratory muscles during exercise in chronic obstructive pulmonary disease (COPD) remains controversial and few data exist regarding respiratory muscle pressure generation in this situation. The inspiratory pressure/time products of the oesophageal and transdiaphragmatic pressure, and the expiratory gastric pressure/time product during exhaustive treadmill walking in 12 patients with severe COPD are reported. The effect of noninvasive positive pressure ventilation during treadmill exercise was also examined in a subgroup of patients (n=6). During free walking, the inspiratory pressure/time products rose early in the walk and then remained level until the patients were forced to stop because of intolerable dyspnoea. In contrast, the expiratory gastric pressure/time product increased progressively throughout the walk. When patients walked the same distance assisted by noninvasive positive pressure ventilation, a substantial reduction was observed in the inspiratory and expiratory pressure/time products throughout the walk. When patients walked with positive pressure ventilation for as long as they could, the pressure/time products observed at exercise cessation were lower than those observed during exercise cessation after free walking. It is concluded that, in severe chronic obstructive pulmonary disease, inspiratory muscle pressure generation does not increase to meet the demands imposed by exhaustive exercise, whereas expiratory muscle pressure generation rises progressively. Inspiratory pressure support was shown to substantially unload all components of the respiratory muscle pump. (+info)
Split-night versus full-night studies for sleep apnoea/hypopnoea syndrome.
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Investigation and treatment of sleep apnoea/hypopnoea syndrome (SAHS) is placing increasing demands on healthcare resources. This workload may be reduced by using split-night studies instead of the standard full-nights of diagnostic polysomnography and continuous positive airway pressure (CPAP) titration. Split-night studies involve polysomnography in the first half of the night followed, if there is an abnormal frequency of apnoeas and hypopneas, by CPAP titration for the remainder of the night. The authors' database of all patients prescribed a CPAP trial 1991-1997 was used to compare long-term outcomes in all 49 (46 accepting CPAP) patients prescribed split-night studies with those in full-night patients, matched 1:2 using an apnoea/ hypopnoea index (AHI) of +/-15% and Epworth score of +/-3 units. Classical symptoms of SAHS were the main reason for the split-night studies (n=27). There were no differences between the groups in long-term CPAP use, median nightly CPAP use (split-night 6.0 h x night-1, interquartile range (IQR) 3.8-7.4, full-night; 6.2 h x night-1, IQR 3.7-7.0, p=0.9), post-treatment Epworth scores and frequency of nursing interventions/clinic visits required. The median time from referral to treatment was less for the split-night patients (13 months, IQR 11-20 months) than for full-night patients (22 months, IQR 12-34 months; p=0.003). Split-night studies, in selected patients, result in equivalent long-term continuous positive airway pressure use to full-night studies with shorter treatment times and less healthcare utilization. (+info)
Long-term effects of CPAP on daytime functioning in patients with sleep apnoea syndrome.
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Daytime sleepiness, impaired cognitive performance and dysphoric mood are often present in patients with obstructive sleep apnoea syndrome (SAS). This prospective controlled study evaluates the effects of treatment with continuous positive airway pressure (CPAP) during 1 yr on daytime functioning in a large group of patients with SAS. The authors studied 80 patients (mean+/-sem 49+/-1 yrs) with SAS with a mean apnoea-hypopnoea index of 60+/-2 h-1, and 80 healthy control subjects matched for sex and age (46+/-1 yrs.). Measurements were obtained at the beginning of the study and 12+/-1 months later, and included: daytime sleepiness (Epworth scale), depression and anxiety (Beck tests), vigilance (Steer-Clear) and reaction time (Psychometer Vigilance Test 192). Drug, coffee and alcohol intake, as well as the sleep schedule, were also recorded. Results showed that, before treatment, patients were more somnolent (p<0.001), anxious (p<0.01) and depressed (p<0.001) than control subjects. Also, they had a longer reaction time (p<0.05) and poorer vigilance (p<0.01). The use of CPAP improved significantly the levels of somnolence (p<0.0001) and vigilance (p<0.01), but failed to modify anxiety and depression. Reaction time changes were minor. Variables with a potential confounding effect did not change during the study. These results provide firm evidence to substantiate the use of continuous positive airway pressure in patients with sleep apnoea syndrome. (+info)
Prediction of difficult mask ventilation.
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BACKGROUND: Maintenance of airway patency and oxygenation are the main objectives of face-mask ventilation. Because the incidence of difficult mask ventilation (DMV) and the factors associated with it are not well known, we undertook this prospective study. METHODS: Difficult mask ventilation was defined as the inability of an unassisted anesthesiologist to maintain the measured oxygen saturation as measured by pulse oximetry > 92% or to prevent or reverse signs of inadequate ventilation during positive-pressure mask ventilation under general anesthesia. A univariate analysis was performed to identify potential factors predicting DMV, followed by a multivariate analysis, and odds ratio and 95% confidence interval were calculated. RESULTS: A total of 1,502 patients were prospectively included. DMV was reported in 75 patients (5%; 95% confidence interval, 3.9-6.1%), with one case of impossible ventilation. DMV was anticipated by the anesthesiologist in only 13 patients (17% of the DMV cases). Body mass index, age, macroglossia, beard, lack of teeth, history of snoring, increased Mallampati grade, and lower thyromental distance were identified in the univariate analysis as potential DMV risk factors. Using a multivariate analysis, five criteria were recognized as independent factors for a DMV (age older than 55 yr, body mass index > 26 kg/m2, beard, lack of teeth, history of snoring), the presence of two indicating high likelihood of DMV (sensitivity, 0.72; specificity, 0.73). CONCLUSION: In a general adult population, DMV was reported in 5% of the patients. A simple DMV risk score was established. Being able to more accurately predict DMV may improve the safety of airway management. (+info)