nCPAP improves abnormal autonomic function in at-risk-for-SIDS infants with OSA.
We evaluated cardiovascular autonomic control and arousability during sleep in infants with obstructive sleep apnea (OSA) before and after 10 +/- 4 (mean +/- SD) days of treatment with nasal continuous positive airway pressure (nCPAP). Six OSA infants and 12 age-matched control infants were studied with polygraphic sleep studies at the age of 13 +/- 4 wk. During the study, 45 degrees head-up tilt tests were performed in slow-wave and rapid eye movement sleep. Blood pressure (BP) and heart rate (HR) were continuously monitored. All OSA infants had decreased initial BP and HR responses, followed by hypotension in two and hypertension in two. OSA infants displayed higher arousal thresholds in response to the tilt in rapid eye movement sleep (P < 0.005) and higher baseline HR (P < 0.05) than controls. nCPAP treatment normalized BP and HR responses as well as arousal thresholds to tilting and stabilized HR levels. OSA in infants may be linked with cardiovascular autonomic control disturbances and decreased arousability during sleep. These defects are improved by control of OSA with nCPAP. (+info)
Effects of continuous positive airway pressure/positive end-expiratory pressure and pressure-support ventilation on work of breathing, using an animal model.
OBJECTIVE: Evaluate the effects of continuous positive airway pressure (CPAP)/positive end-expiratory pressure (PEEP) and pressure support ventilation (PSV) on work of breathing (WOB). METHODS: With 13 anesthetized lambs we measured WOB with an esophageal balloon and flow signals. All the animals were sedated, intubated, and ventilated, using 2 pediatric ventilators (Servo 300 and VIP Bird). Ventilator settings were CPAP of 0, 5, and 10 cm H(2)O and PSV of 5 and 10 cm H(2)O with PEEP of 0, 5, and 10 cm H(2)O. Data were analyzed with 2-way analysis of variance. RESULTS: With the Servo 300 the total WOB (WOB(T)) increased between CPAP/PEEP of 0 and 10 cm H(2)O (p +info)
Leptin and ghrelin levels in patients with obstructive sleep apnoea: effect of CPAP treatment.
Serum leptin and ghrelin levels were investigated in patients with obstructive sleep apnoea (OSA) syndrome before and during continuous positive airways pressure (CPAP) treatment and compared with body mass index (BMI)-matched controls without OSA. Male patients (n=30) with OSA (apnoea/hypopnoea index=58+/-16, BMI=32.6+/-5.3 kg x m(-2)) underwent CPAP treatment. Fasting leptin and ghrelin were measured at baseline and 2 days, and in the case of leptin 2 months after initiation of treatment. Baseline plasma ghrelin levels were significantly higher in OSA patients than in controls. After 2 days of CPAP treatment, plasma ghrelin decreased in almost all OSA patients (n=9) to levels that were only slightly higher than those of controls (n=9). Leptin levels did not change significantly from baseline after 2 days of CPAP treatment, but were higher than in the control group. After 8 weeks, leptin levels decreased significantly, although the BMI of the patients showed no change. The decrease in leptin levels was more pronounced in patients with a BMI <30 kg x m(-2). These data indicate that the elevated leptin and ghrelin levels are not determined by obesity alone, since they rapidly decreased during continuous positive airways pressure therapy. (+info)
Heated humidification of nasal continuous positive airway pressure (nCPAP) reduces upper airway symptoms and improves initial use in obstructive sleep apnoea syndrome (OSAS). The present study aimed to assess the effect of heated humidification of nCPAP on upper airway symptoms and initial use in obstructive sleep apnoea. This study was of a randomised, crossover design. Subjects with polysomnographically confirmed OSAS were randomised to 3 weeks nCPAP treatment with heated humidification (nCPAP-humid) or placebo humidification (nCPAP pl-humid). Objective and subjective nCPAP use, upper airway symptoms, and treatment satisfaction were compared. Thirty seven of 42 patients completed the protocol. nCPAP-humid reduced the frequency of adverse upper airway symptoms. nCPAP use over 3 weeks was greater with nCPAP-humid compared with nCPAP pl-humid. No difference was found between the treatment arms in terms of subjective treatment satisfaction or alertness. Heated humidification of nasal continuous positive airway pressure reduces upper airway symptoms and is associated with a small increase in initial use but not subjective sleepiness or treatment satisfaction. The results support the use of heated humidification as a strategy to reduce side-effects related to continuous positive airway pressure but not routine initial use. (+info)
Control of upper airway muscle activity in younger versus older men during sleep onset.
Pharyngeal dilator muscles are clearly important in the pathophysiology of obstructive sleep apnoea syndrome (OSA). We have previously shown that the activity of both the genioglossus (GGEMG) and tensor palatini (TPEMG) are decreased at sleep onset, and that this decrement in muscle activity is greater in the apnoea patient than in healthy controls. We have also previously shown this decrement to be greater in older men when compared with younger ones. In order to explore the mechanisms responsible for this decrement in muscle activity nasal continuous positive airway pressure (CPAP) was applied to reduce negative pressure mediated muscle activation. We then investigated the effect of sleep onset (transition from predominantly alpha to predominantly theta EEG activity) on ventilation, upper airway muscle activation and upper airway resistance (UAR) in middle-aged and younger healthy men. We found that both GGEMG and TPEMG were reduced by the application of nasal CPAP during wakefulness, but that CPAP did not alter the decrement in activity in either muscle seen in the first two breaths following an alpha to theta transition. However, CPAP prevented both the rise in UAR at sleep onset that occurred on the control night, and the recruitment in GGEMG seen in the third to fifth breaths following the alpha to theta transition. Further, GGEMG was higher in the middle-aged men than in the younger men during wakefulness and was decreased more in the middle-aged men with the application of nasal CPAP. No differences were seen in TPEMG between the two age groups. These data suggest that the initial sleep onset reduction in upper airway muscle activity is due to loss of a 'wakefulness' stimulus, rather than to loss of responsiveness to negative pressure. In addition, it suggests that in older men, higher wakeful muscle activity is due to an anatomically more collapsible upper airway with more negative pressure driven muscle activation. Sleep onset per se does not appear to have a greater effect on upper airway muscle activity as one ages. (+info)
Effect of continuous positive airway pressure treatment on elderly Chinese patients with obstructive sleep apnea in the prethrombotic state.
OBJECTIVES: To characterize the prethrombotic state (PTS) in elderly Chinese patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and the effect of nasal continuous positive airway pressure (nCPAP) ventilation on their PTS. METHODS: Forty-one elderly patients with moderate and severe OSAHS were enrolled into the OSAHS group and underwent nCPAP treatment. Their blood samples were drawn at 6:00 am and 4:00 pm before and during nCPAP treatment, respectively, to test hemocrit, platelet aggregation (PAG), whole blood viscosity (WBV), plasma fibrinogen (fng), prothrombin time (PT) and activated partial thromboplastin time (APTT). All blood factors were also tested in a control group consisting of 32 healthy elderly Chinese with neither OSAHS nor cerebrocardiac vascular disease. RESULTS: In the OSAHS group there was a significantly higher hemocrit, WBV, fng, and a significantly shorter PT and APTT at 6:00 am compared to 4:00 pm before nCPAP treatment, while there was no significant difference among all blood test factors between 6:00 am and 4:00 pm on day 30 of the nCPAP treatment. In the OSAHS group, the hemocrit, WBV, PAG and plasma fng were significantly lower and the PT and APTT were significantly longer at 6:00 am on day 30 of the nCPAP treatment compared to 6:00 am before the nCPAP treatment. A significantly lower hemocrit, but a much longer PT and APTT were observed at 4:00 pm on day 30 of the treatment, compared with 4:00 pm before the treatment. No significant difference among the blood test factors was found between 6:00 am and 4:00 pm blood in the control group or between the control and OSAHS groups after 30 days of nCPAP treatment. CONCLUSION: In elderly Chinese OSAHS patients, PTS could be effectively eliminated by nCPAP treatment. (+info)
Non-invasive ventilation in acute respiratory failure: a randomised comparison of continuous positive airway pressure and bi-level positive airway pressure.
OBJECTIVES: To determine whether there is a difference in required duration of non-invasive ventilation between continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BiPAP) in the treatment of a heterogeneous group of emergency department (ED) patients suffering acute respiratory failure and the subgroup of patients with acute pulmonary oedema (APO). Secondary objectives were to compare complications, failure rate, disposition, length of stay parameters, and mortality between the treatments. METHODS: This prospective randomised trial was conducted in the emergency departments of three Australian teaching hospitals. Patients in acute respiratory failure were randomly assigned to receive CPAP or BiPAP in addition to standard therapy. Duration of non-invasive ventilation, complications, failure rate, disposition, length of stay (hospital and ICU), and mortality were measured. RESULTS: 101 patients were enrolled in the study (CPAP 51, BiPAP 50). The median duration of non-invasive ventilation with CPAP was 123 minutes (range 10-338) and 132 minutes (range 20-550) for BiPAP (p = 0.206, Mann-Whitney). For the subgroup suffering APO, 36 were randomised to CPAP and 35 to BiPAP. For this group the median duration of non-invasive ventilation for CPAP was 123 minutes (range 35-338) and 133 minutes (range 30-550) for BiPAP (p = 0.320, Mann-Whitney). CONCLUSIONS: These results suggest that there is no significant difference in the duration of non-invasive ventilation treatment between CPAP and BiPAP when used for the treatment of acute respiratory failure in the ED. There was also no significant difference between the groups in secondary end points. (+info)
A comparison of public and private obstructive sleep apnea clinics.
The aim of the present study was to compare the clinical findings and polysomnography results obtained at public and private clinics in Brazil, the follow-up after diagnosis, and the therapeutic aspects related to continuous positive airway pressure. Patients who snore and who have obstructive sleep apnea were retrospectively divided into two groups, i.e., public clinic (N=307) and private clinic (N=317). Data concerning age, sex, body mass index (BMI), neck circumference, medical history, sleepiness scale, follow-up after diagnosis, and acceptance of continuous positive airway pressure therapy were collected. Mean age was 50 +/- 12 (range: 15-80) for public patients and 48 +/- 12 years (range: 19-91) for private patients. Mean BMI was 30 +/- 6 (range: 19-67) for public patients and 31 +/- 6 kg/m (range: 21-59) for private patients. The public clinic had a significantly higher frequency of women than the private clinic (M:F ratio of 2.0:1 and 6.9:1, respectively). The condition of private patients (apnea-hypopnea index=31 +/- 25) was more severe than that of public patients (apnea-hypopnea index=25 +/- 24 events/h; P=0.0004). In the public and private clinics, 19 and 15% of patients were snorers, respectively, and 81 and 85% of them had sleep apnea. After diagnosis, follow-up was longer in the private group. The continuous positive airway pressure acceptance was similar for both groups (32 vs 35%), but patients from the public clinic abandoned treatment more than private ones (65 vs 13%). Social status was significant in terms of the severity of obstructive sleep apnea age and gender distribution. Private patients look for a diagnosis earlier in the course of the disease than public patients, adhere more to follow-up, and abandon continuous positive airway pressure treatment less than public patients do. (+info)