Randomised, controlled trial of nasal continuous positive airway pressure in the extubation of infants weighing 600 to 1250 g

AIM: To determine whether extubation to nasal continuous airway pressure (NCPAP) results in a greater proportion of infants remaining free of additional ventilatory support for one week after extubation compared with those extubated directly to headbox oxygen. METHODS: A randomised, controlled, clinical trial was conducted at the neonatal intensive care unit of the Royal Women's Hospital, Melbourne, of infants with birthweights between 600 and 1250 g, ventilated via an endotracheal tube for more than 12 hours, requiring less than 50% oxygen, a ventilator rate < or = 20/minute, considered by the clinical management team to be ready for extubation. Infants were randomly allocated either to NCPAP or to oxygen administered via a headbox. Success was defined by no requirement for additional ventilatory support over the week following extubation. Failure criteria were (i) apnoea; (ii) absolute increase in oxygen requirement greater than 15% above than required before extubation; or (iii) respiratory acidosis (pH < 7.25 with pCO2 > 6.67 kPa). RESULTS: Thirty one of 47 (66%) infants were successfully extubated to NCPAP compared with 18 of 45 (40%) for headbox oxygen. The increase in failure rate in the headbox group was due primarily to increased oxygen requirements in this group. Of the 27 who failed headbox oxygen, 26 were given a trial of NCPAP and 13 did not require endotracheal reintubation. There was no significant difference between the groups in the total number of days of assisted ventilation or the duration of inpatient stay. CONCLUSIONS: NCPAP applied prophylactically after endotracheal extubation reduces the incidence of adverse clinical events that lead to failure of extubation in the seven days after extubation. This reduction is clinically important. The benefits of NCPAP do not seem to be associated with an increased incidence of unwanted side effects.     

Therapy with nasal CPAP (continuous positive airway pressure) in patients with obstructive sleep apnea syndrome (OSAS). I: Long-term acceptance of nasal CPAP

BACKGROUND: Nocturnal ventilation with nCPAP has been established as the safest and most efficient nonsurgical treatment for OSAS. Long-term results, however, are determined by the patients' compliance with therapy. The aim of this study was the objective measurement of long-term acceptability of nCPAP therapy in all patients receiving this treatment in our sleep laboratory between January 1990 and March 1995. METHODS: We prospectively investigated 41 patients (36 male, 5 female) with moderate to severe OSAS who received nCPAP therapy. Mean time of follow-up was 20.6 months, ranging from 1.2 to 53.5 months. Therapy was indicated when OSAS was confirmed by cardiorespiratory polygraphy and either (1) the patient complained of daytime sleepiness or (2) the patient possessed an apnea-hypopnea index greater than 30/h or when the mean oxygen desaturation was below 80% regardless of the presenting symptoms. The compliance with treatment was defined as a mean rate of use of over 5 hours per night calculated from the time counter on the nCPAP machine. RESULTS: 33 patients (88.5%) have continued using nCPAP until the present time but only 24 patients (59%) met our criteria for long-term acceptance and this group was identified as responders. We found no significant differences in age, body mass index, apnea-hypopnea index, and nCPAP-pressure between responders and non-responders. CONCLUSION: Although nCPAP is the safest treatment for OSAS, there is still a large group of patients with moderate to severe OSAS who are not efficiently treated with nCPAP because of the low long-term acceptability of this therapy. With respect to this group of patients, surgical approaches have to be considered as an alternative therapy.     

Therapy with nasal CPAP (continuous positive airway pressure) in patients with obstructive sleep apnea syndrome (OSAS). II: Side-effects of nCPAP therapy. Effect on long-term acceptance

BACKGROUND: nCPAP is a well established method for the management of OSAS. The aim of this study was to evaluate long-term side effects and complications of nCPAP therapy and their influence on the patients compliance with treatment. PATIENTS AND METHODS: Forty-one patients with OSAS were interviewed by questionnaire to elucidate the problems and adverse effects of their nCPAP therapy. The patients were divided into responders and non-responders. Non-responding OSAS patients were using their nCPAP devices less then 5 hours each night by definition. RESULTS: The number of side effects and type of complication during nCPAP therapy were the same in both the responding and non-responding groups. The most frequently reported problems were a tender region on the bridge of the nose and discomfort associated with a dry nasal mucosa. Although nCPAP treatment was initially accepted by most patients, adverse effects and other difficulties decreased patient compliance, with time, in many cases. CONCLUSIONS: Despite there being no difference between responders and non-responders with respect to the number and severity of complications, it should not be presumed that these side effects do not influence long-term patient compliance with nCPAP therapy. Patients who suffer from symptoms of OSAS tend to accept these adverse effects, while those who do not feel limited by their disease are less persistent in their use of this treatment modality. Identification and elimination of the problems associated with the use of nCPAP equipment may increase longterm patient compliance. Close monitoring in the outpatient department combined with intermittent inpatient assessment in the sleep laboratory will also help to improve acceptance of nCPAP therapy.     

Randomized placebo-controlled crossover trial of continuous positive airway pressure for mild sleep Apnea/Hypopnea syndrome

The minimal disease severity at which patients with the sleep apnea/hypopnea syndrome (SAHS) gain benefit from treatment is not well characterized, although a pilot study of continuous positive airway pressure (CPAP) therapy showed daytime improvements in patients with 5 to 15 apneas + hypopneas per hour slept (AHI). We have thus performed a second, larger, randomized, placebo- controlled study in a prospective series of 34 patients (13 female) with mild SAHS (AHI 5 to 15) and daytime sleepiness. Patients spent 4 wk on CPAP treatment and 4 wk on an oral placebo, with randomization of treatment order, and daytime assessments on the last day of each treatment. Effective CPAP use averaged 2.8 +/- 2.1 h (mean +/- SD) per night. Compared with placebo, CPAP improved symptom score (p < 0.01), subjective (Epworth; p < 0.01) but not objective (maintenance of wakefulness test; p > 0.2) sleepiness, performances on 2 of 7 cognitive tasks (p < 0.02), depression score (p < 0.01), and five subscales of the SF-36 health/functional status questionnaire (p 相似文献   

鼻塞持续气道正压通气在早产儿低氧血症中的应用及护理

新生儿低氧血症是呼吸功能障碍时的常见表现,可由通气/换气中任何环节的障碍所致.严重者伴有组织缺氧,导致细胞代谢和器官功能障碍,甚至威胁生命.新生儿脑细胞对缺氧很敏感,持续严重缺氧常发生不可逆的损伤.川新生儿出现呼吸功能障碍及低氧血症时,除积极治疗原发病外,适当增加供氧提高肺泡氧分压,配合机械通气以改善通换气功能等方法.     

Tracheal pressure triggering a demand-flow continuous positive airway pressure system decreases patient work of breathing

OBJECTIVES: Triggering a ventilator "ON" at the carinal end of the endotracheal tube decreases imposed work of breathing by bypassing the resistance imposed by the breathing circuit and the endotracheal tube. We compared work of breathing during spontaneous ventilation between three methods of triggering the ventilator "ON": a) conventional pressure triggering from inside the ventilator; b) flow-by triggering; or c) tracheal pressure triggering at the carinal end of the endotracheal tube. We hypothesized that the work of breathing would be substantially decreased with tracheal pressure triggering compared with conventional pressure and flow-by methods in patients receiving continuous positive airway pressure. DESIGN: Clinical, prospective study. SETTING: University teaching hospital. PATIENTS: Fourteen adults diagnosed with acute respiratory failure. INTERVENTIONS: All patients were breathing spontaneously at an FIO2 of 0.30 to 0.40 and received 5 cm H2O of continuous positive airway pressure. Three different methods of triggering the ventilator while set in the continuous positive airway pressure mode were administered in random order. MEASUREMENTS AND MAIN RESULTS: Real-time measurements of esophageal pressure and tidal volume were integrated with a respiratory monitor (CP-100, Bicore, Riverside, CA) that uses the Campbell diagram to calculate total work of breathing. Imposed work of breathing was calculated by integrating tidal volume with the pressure at the carinal end of the endotracheal tube. Physiologic work of breathing was calculated by subtracting imposed work of breathing from the total work of breathing. Breathing frequency, the index of rapid shallow breathing (breathing frequency/tidal volume), peak inspiratory flow rate demand, exhaled minute ventilation, and the duration of respiratory muscle contraction assessed by the ratio of inspiratory time to total cycle time were also measured. Data were analyzed by Friedman's repeated-measures analysis of variance on ranks. Alpha was set at .05 for statistical significance. Imposed work of breathing decreased to approximately zero during tracheal pressure triggering. As a result, total work of breathing decreased by approximately 40% compared with the flow-by and conventional methods. During tracheal pressure triggering only, airway pressure increased above baseline pressure to approximately 11 cm H2O, which resembled pressure-support ventilation. Also, during tracheal pressure triggering, tidal volume and peak inspiratory flow rate were significantly increased, while the pressure-time product and the index of rapid shallow breathing were significantly decreased. Hemodynamic status and oxygen saturation were not clinically affected. CONCLUSIONS: The tracheal pressure triggering of a demand-flow continuous positive airway pressure system creates an effect similar to pressure-support ventilation that significantly decreases imposed work of breathing and, thus, total work of breathing. We recommend moving the triggering site of the ventilator to the carinal end of the endotracheal tube.     

Changes in cardiac output do not explain the higher rate of myocardial infarction associated with the use of bilevel compared with continuous positive airway pressure

A case of vaginal evisceration resulting from sliding on a water chute is described. The treatment and mechanism of this rare injury are discussed.     

Changes in urinary uric acid excretion in obstructive sleep apnea before and after therapy with nasal continuous positive airway pressure

STUDY OBJECTIVE: To assess the utility of urinary uric acid excretion as a marker of nocturnal hypoxia in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) before and after the institution of nasal continuous positive airway pressure (CPAP). DESIGN: Prospective, open. SETTING: Sleep Disorders Laboratory, Veterans Affairs Medical Center. PARTICIPANTS: Thirty consecutive male subjects, 20 with OSAHS and 10 without OSAHS. MEASUREMENTS AND METHODS: Spot morning urine and venous blood samples were obtained in all subjects; samples were also obtained after the application of CPAP in those with OSAHS. Uric acid excretion, normalized to creatinine clearance, was calculated as the product of urinary uric acid and serum creatinine concentrations divided by urine creatinine concentration. In patients with OSAHS, uric acid excretion was 0.55+/-0.1 mg/dL before CPAP therapy and decreased to 0.30+/-0.01 mg/dL after CPAP therapy (p < 0.001). The latter value did not differ significantly from the mean value (0.32+/-0.03 mg/dL) in the control group. Uric acid excretion in OSAHS patients correlated significantly with the apnea-hypopnea index (r=0.42; p<0.0003). CONCLUSION: Uric acid excretion is increased in OSAHS patients and normalizes after CPAP treatment, most likely reflecting differences in tissue oxygenation between the two conditions. Further studies in large number of patients may confirm the usefulness of this simple test for diagnosis and follow-up of patients with OSAHS.     

Relative occurrence of flow limitation and snoring during continuous positive airway pressure titration

OBJECTIVE: To distinguish between the existence of detached ciliary tufts (DCTs) and the possibility of protozoa in the sputum of asthma patients. STUDY DESIGN: One hundred six samples of sputum obtained from 97 patients hospitalized with either asthma or other respiratory diseases were examined blindly. The combination of such criteria as movement, absence of basal plate, existence of red granules, positivity for ultraviolet light and Heidenhain's iron hematoxylin stain (for protozoa) was employed to distinguish between DCTs and true protozoa. RESULTS: The presence of ameboflagellates in sputum has a diagnostic accuracy of 86% in predicting or ruling. out the possibility of acute asthma. CONCLUSION: The presence of ameboflagellate forms is closely related to the existence of bronchial asthma, and these result reflect some etiopathogenic significance in asthma.     

Differential effects of nasal continuous positive airway pressure on reversible or fixed upper and lower airway obstruction

Our study was to assess whether there were differential effects of nasal continuous positive airway pressure (nCPAP) on different kinds of obstruction in either upper or lower airways in patients with chronic obstructive pulmonary disease (COPD). nCPAP (6 cmH2O for ten minutes) was applied to 7 patients with reversible extrathoracic upper airway obstruction (RUAO) and 3 patients with fixed extrathoracic upper airway obstruction (FUAO). Eighteen stable asthmatics, receiving methacholine challenge to induce a more than 20% reduction in FEV1, were randomly investigated for the effect of nCPAP or sham pressure on reversible lower airway obstruction. Nine stable COPD patients were enrolled to study the effect on irreversible lower airway obstruction. Maximal expiratory and inspiratory flow volume curves and dyspnoea scores were obtained before and after immediate withdrawal of nCPAP. In the RUAO group, nCPAP significantly improved stridor and dyspnoea scores, decreased the ratio of FEF50/FIF50 from 2.05 +/- 0.25 to 1.42 +/- 0.16, and increased peak inspiratory flow (PIF) as well as forced inspiratory vital capacity by 26 +/- 8% and 9 +/- 4%, respectively. In expiratory phase, there was no significant change in pulmonary functions. In asthmatics, nCPAP significantly reversed methacholine-induced bronchoconstriction increasing forced vital capacity by 10 +/- 3%, FEV1 by 15 +/- 4% and PIF by 32 +/- 11%. nCPAP significantly increased the response to bronchodilators. The improvement in airflow rate persisted for at least 5 min after nCPAP withdrawal and was highly correlated with the response to bronchodilators. There was no significant effect of nCPAP on airflow rate in COPD patients. Subjective dyspnoea score changes paralleled the pulmonary function improvement. We conclude that there are differential effects of nCPAP on airflow rates in patients with different nature of airway obstruction. Patients with airway obstruction caused by structural changes may not benefit from the use of nCPAP in improving airflow rates.     

Effects of nasal continuous positive airway pressure therapy on respiratory parameters of upper airway patency in patients with obstructive sleep apnea syndrome

OBJECTIVES: To assess whether an initial treatment with nasal continuous positive airway pressure (NCPAP) therapy, applied for one night, had any effect on airway patency. METHODS: In 18 patients with obstructive sleep apnea syndrome (OSAS), we measured the total resistance of the respiratory system (Rrs) and their relevant lung functions before and after polysomnography, with and without NCPAP therapy. The Rrs was measured at 3 Hz with the forced oscillation technique. The overnight changes in the specific respiratory conductance (SGrs=reciprocal of the Rrs per unit lung volume) was also calculated in the sitting position. Since many reports have suggested that obesity, through fat deposits around the pharynx, can affect the mechanical and neuromuscular properties of the upper airway, we also investigated if the degree of obesity was related to the magnitude of improvement in these parameters. RESULTS: After the first night of NCPAP therapy, the Rrs decreased (sitting: 4.8+/-0.4 vs 4.3+/-0.4 cm H20/L/s, p < 0.05; lying: 6.5+/-0.4 vs 5.6+/-0.4 cm H20/L/s, p < 0.05) and the maximal voluntary ventilation increased in the morning (sitting: 101.6+/-5.8% vs 106.4+/-4.5%, p < 0.05; lying: 91.2+/-5.4% vs 97.9+/-4.7%, p < 0.05). The overnight difference in the SGrs showed a significant improvement after the initial treatment with NCPAP therapy (p < 0.05). However, the lung volume, flow volume loop, and closing volume in the morning did not change significantly after the therapy. An overnight decrease in the Rrs following NCPAP therapy is significantly correlated with the body mass index (sitting: r=0.54, p < 0.05; lying: r=0.61, p < 0.01). CONCLUSION: The improvements in Rrs without changes in spirometry may reflect improved upper airway patency after NCPAP therapy. The degree of obesity is suggested to be associated with the treatment effect on upper airway in patients with OSAS.     

Acute effects of nasal continuous positive airway pressure on 24-hour blood pressure and catecholamines in patients with obstructive sleep apnea

OBJECTIVE: To estimate the risk for spina bifida associated with the common mutation C677T of the MTHFR gene in a country with a relatively low prevalence of NTDs. DESIGN: Case-control study. SUBJECTS: Cases: 203 living patients affected with spina bifida (173 myelomeningocele and 30 lipomeningocele); controls: 583 subjects (306 young adults and 277 unselected newborns) from northern and central-southern Italy. SETTING: Cases: three spina bifida centres; young adult controls: DNA banks; newborn controls: regional neonatal screening centres. MAIN OUTCOME MEASURES: Prevalence of the C677T genotypes in cases and controls by place of birth; odds ratios for spina bifida and estimated attributable fraction. RESULTS: The prevalence of T/T, T/C, and C/C genotype was 16.6%, 53.7%, and 29.7% in controls and 25.6%, 43.8%, and 30.6% in cases, respectively. We found no differences between type of defect or place of birth. The odds ratio for spina bifida associated with the T/T genotype v C/C plus T/C was 1.73 (95% CI 1.15, 2.59) and the corresponding attributable fraction was 10.8%. No increased risk was found for heterozygous patients (OR=0.79, 95% CI 0.53-1.18). CONCLUSION: This study, as well as the meta-analysis we updated, shows that homozygosity for the MTHFR C677T mutation is a moderate risk factor in Europe, and even in Italy where there is a relatively low prevalence of spina bifida. The estimated attributable fraction associated with this risk factor explains only a small proportion of cases preventable by periconceptional folic acid supplementation. Thus, other genes involved in folate-homocysteine metabolism, their interaction, and the interaction between genetic and environmental factors should be investigated further.     

Cerebral hemodynamic changes in sleep apnea syndrome and effect of continuous positive airway pressure treatment

BACKGROUND AND OBJECTIVE: A clear association among snoring, sleep apnea, and increased risk of stroke has been shown by previous studies. However, the possible role played by sleep apnea in the pathogenesis of cerebrovascular disease is subject to debate. To evaluate the influence of hemodynamic changes caused by obstructive sleep apnea syndrome (OSAS), we investigated cerebrovascular reactivity to hypercapnia in patients with OSAS. METHODS: The study was performed at baseline and after 1 night and 1 month of nasal continuous positive airway pressure (n-CPAP) therapy, with patients in the waking state (8:00 to 8:30 AM and 5:30 to 6:00 PM) with transcranial Doppler ultrasonography. Cerebrovascular reactivity was calculated with the breath-holding index (BHI). RESULTS: In the baseline condition, compared with normal subjects, patients with OSAS showed significantly lower BHI values in both the morning (0.57 versus 1.40, p < 0.0001) and the afternoon (1.0 versus 1.51, p < 0.0001). Cerebrovascular reactivity was significantly higher in the afternoon than it was in the morning in both patients (p < 0.0001) and controls (p < 0.05). In patients, the BHI returned to normal values, comparable with those of control subjects, after both 1 night and 1 month of n-CPAP therapy. CONCLUSIONS: These findings suggest an association between OSAS and diminished cerebral vasodilator reserve. This condition may be related to the increased susceptibility to cerebral ischemia in patients with OSAS, particularly evident in the early morning.     

Long-term evolution of daytime somnolence in patients with sleep apnea/hypopnea syndrome treated by continuous positive airway pressure

We demonstrated in a previous study that excessive daytime sleepiness (EDS) in patients who have sleep apnea/hypopnea syndrome (SAHS) and are undergoing continuous positive airway pressure (CPAP) treatment improved differently in two groups of patients: in group I, multiple sleep latency tests (MSLT) were normalized after 50 days of treatment (individual value > 10 minutes), whereas they remained low (individual value < 10 minutes) in group II, with a significant difference between groups. To evaluate the long-term evolution of daytime somnolence under nasal CPAP treatment, five patients from group I and seven patients from group II underwent a new polysomnography and MSLT 4 years after the previous study. Clinical, polysomnographic and MSLT results obtained at baseline before treatment (T1), after the initial 50-day period of CPAP treatment (T2), and after 4 years (T3) were compared. The significant difference in mean MSLT value between the two groups previously observed at T1 and T2 disappeared at T3 (group I: 12.4+/-5.9 minutes; group II: 9.7+/-5.9 minutes). We found that this long-term improvement in excessive daytime somnolence was independent of the initial MSLT value, the severity of SAHS, and the initial MSLT changes under nasal CPAP. Long-term MSLT evolution was significantly correlated to CPAP compliance. These results demonstrate that even in the absence of a significant increase in MSLT at the beginning of CPAP treatment, further improvement is still possible several years later, which may encourage the regular, long-term use of nasal CPAP by patients.     

Reversal of sinus arrest and atrioventricular conduction block in patients with sleep apnea during nasal continuous positive airway pressure

Sinus arrest and atrioventricular (AV) block have been demonstrated in as much as 30% of patients with sleep apnea (SA). The reversal of heart block after tracheostomy has been shown. Nasal continuous positive airway pressure (nCPAP) now is widely used as the treatment of SA, but little data are available on the effect of nCPAP on heart block in patients with SA. During a 17-mo period 239 patients were found to have SA in an ambulatory study. Heart block was identified in 17 (16 male, one female) of these patients. Standard polysomnography and two-channel long-term ECG before and during nCPAP therapy were performed in order to assess the effect of nCPAP on SA and heart block. Mean age of the 17 patients was 50.7 yr (range, 27 to 78 yr), mean respiratory disturbance index (RDI) was 90/h (SD +/- 36.1) before nCPAP and 6/h (SD +/- 6.2) on the second treatment night. The number of episodes of heart block during sleep decreased significantly (p < 0.001) from 1,575 before therapy to 165 during nCPAP. In 12 patients (70.6%) heart block was totally prevented by nCPAP. In another three patients, there was a 71 to 97% reduction in the number of episodes of heart block on the second treatment night, and in two of them a complete reversal occurred thereafter. Two patients exhibited an increase in block frequency during nCPAP, which was reversed after 4 wk of nCPAP in one but persisted in the other.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of continuous positive airway pressure on obstructive sleep apnea and left ventricular afterload in patients with heart failure

BACKGROUND: The objectives of this study were to determine the effects of continuous positive airway pressure (CPAP) on blood pressure (BP) and systolic left ventricular transmural pressure (LVPtm) during sleep in congestive heart failure (CHF) patients with obstructive sleep apnea (OSA). In CHF patients with OSA, chronic nightly CPAP treatment abolishes OSA and improves left ventricular (LV) ejection fraction. We hypothesized that one mechanism whereby CPAP improves cardiac function in CHF patients with OSA is by lowering LV afterload during sleep. METHODS AND RESULTS: Eight pharmacologically treated CHF patients with OSA were studied during overnight polysomnography. BP and esophageal pressure (Pes) (ie, intrathoracic pressure) were recorded before the onset of sleep and during stage 2 non-rapid eye movement sleep before, during, and after CPAP application. OSA was associated with an increase in systolic BP (from 120.4+/-7.8 to 131.8+/-10.6 mm Hg, P<0.05) and systolic LVPtm (from 124.4+/-7.7 to 137.2+/-10.8 mm Hg, P<0.05) from wakefulness to stage 2 sleep. CPAP alleviated OSA, improved oxyhemoglobin saturation, and reduced systolic BP in stage 2 sleep to 115.4+/-8.5 mm Hg (P<0.01), systolic LVPtm to 117.4+/-8.5 mm Hg (P<0.01), heart rate, Pes amplitude, and respiratory rate. CONCLUSIONS: In CHF patients with OSA, LV afterload increases from wakefulness to stage 2 sleep. By alleviating OSA, CPAP reduces LV afterload and heart rate, unloads inspiratory muscles, and improves arterial oxygenation during stage 2 sleep. CPAP is a nonpharmacological means of further reducing afterload and heart rate during sleep in pharmacologically treated CHF patients with OSA.     

Abnormal autonomic stress responses in obstructive sleep apnoea are reversed by nasal continuous positive airway pressure

Obstructive sleep apnoea (OSA) is associated with abnormalities in autonomic stress tests, which are tests of cardiovascular response in the autonomic nervous system (ANS). The level of abnormality has been related to the level of overnight arterial oxygen saturation (Sa,O2). We have studied ANS function pre- and post-treatment with nasal continuous positive airway pressure (nCPAP) in six males with moderately severe or severe OSA (apnoea/hypopnoea index (AHI) median 51 (range 14-74 events.h-1 of sleep). Tests consisted of heart rate responses to Valsalva manoeuvre, deep breathing, and change of posture from lying to standing. In addition, systolic blood pressure (SBP) response to standing and diastolic blood pressure (DBP) response to handgrip were studied. Each abnormal test (compared to published normal values) scored +1.0 and each marginal test result (90-95% confidence interval for normals) scored +0.5. A total score was calculated for the five tests performed in the evening and morning (maximum score 10 per patient). Patients had been receiving treatment for more than 1 year (median 471 (389-624) days) and objective compliance was monitored by a clock counter in the nCPAP machines. Five of six patients had regularly used nCPAP (mean 7.8 h.night-1) and all showed a normalization in ANS test score: pre-nCPAP 2 (1-4.5), post-nCPAP 0.2 (0-0.5) (p < 0.05, Wilcoxon signed rank test). One poorly compliant subject (No. 6; nCPAP 3 h.night-1) had a deterioration in ANS test score: 1 pre-nCPAP to 1.5 post-nCPAP. The improvement in ANS test score in the five compliant patients was positively correlated with an improvement in mean Sa,O2 during sleep posttreatment. We conclude that successful treatment of obstructive sleep apnoea leads to normalization of impaired autonomic stress responses.