Pierre Delguste

Acceptance and long-term compliance with nCPAP in patients with obstructive sleep apnoea syndrome

Previous studies have generally shown poor effective long-term compliance with nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnoea syndrome (OSAS). We performed a retrospective study of patients treated with nCPAP for more than one year. Compliance was defined as the average number of hours of nCPAP use per day, where hours of use were obtained from the built-in time counter of the nCPAP device, after deduction of the 10% difference between effective use and time counters previously shown by others. We present data on the first 95 patients for whom results were available. The follow-up period was 784 +/- 366 (mean +/- SD) days for the whole group. Compliance was 5 +/- 1.8 h. For a subgroup of 36 patients, we had data on two consecutive follow-up periods (673 +/- 235 and 390 +/- 147 days for the first and second period, respectively). Compliance remained stable (5.2 +/- 1.5 and 5 +/- 2.3 h, respectively). For the whole group, a significant correlation was found between compliance and sleep fragmentation expressed as the movement arousal index (r = 0.226). During a similar 3 year period, 155 patients with a confirmed diagnosis of OSAS were offered a nCPAP trial. CPAP was actually delivered for home use to 117 patients (76%). During this same 3 year period, only 21 patients out of a total of 192 followed-up in our institution quit treatment, mainly due to intolerance or cure. These results indicate that in a nonselected group of obstructive sleep apnoea syndrome patients a high and stable compliance with nasal continuous positive pressure can be achieved, contradicting recent results of other series.

Effects of nasal positive-pressure hyperventilation on the glottis in normal sleeping subjects

We have previously observed that, in normal awake subjects passively hyperventilated with intermittent positive-pressure ventilation delivered through nasal access (nIPPV), the glottis could interfere with the ventilation. We report on data obtained in the same subjects during stable sleep. In all cases, the glottis was continuously observed through a fiber-optic bronchoscope, and other indexes were also continuously recorded. Mechanical ventilation was progressively increased up to 30 l/min. We have observed during passive nIPPV in stable sleep that increases in delivered minute ventilation (VEd) resulted in progressive narrowing of the glottic aperture, with increases in inspiratory resistance and progressive reductions in the percentage of the delivered tidal volume effectively reaching the lungs. For a given level of VEd, comparisons showed that the glottis was significantly narrower during sleep than during wakefulness and that the glottis was significantly narrower during stage 2 than during stages 3/4 non-rapid-eye-movement sleep. Moreover, when CO2 is added to the inspired air, glottic aperture increased in five of nine trials without changes in sleep stage. We also observed a significant negative correlation between glottic width and the VED, independent of the CO2 level. We conclude that during nIPPV glottis narrowing results in a decrease in the proportion of the delivered tidal volume reaching the lungs.

Upper airway obstruction during nasal intermittent positive-pressure hyperventilation in sleep

Episodes of apnoea for up to 1 min were observed in association with hypocapnia caused by passive nasal intermittent positive-pressure mechanical hyperventilation in 3 of 4 patients during sleep. Apnoea seemed to be caused by complete upper airways obstruction; we suggest that this finding was caused by active glottic closure. Avoidance of excessive hypocapnia during positive-pressure ventilation might help to avoid central-nervous-system mediated apnoeic episodes.

Sleep in ventilatory failure in restrictive thoracic disorders. Effects of treatment with non invasive ventilation

STUDY OBJECTIVES Hypercapnic ventilatory failure due to restrictive disorders may have a negative impact on sleep architecture. Non-invasive ventilation (NIV) may improve arterial blood gases but may adversely affect sleep. We assessed sleep structure and blood gases before and during NIV in patients with restrictive disorders in hypercapnic ventilatory failure. DESIGN Retrospective cohort study. SETTING Sleep laboratory of Saint-Luc University Hospital (Belgium). PATIENTS Chart review of all patients with predominantly restrictive disorders and respiratory failure seen between 1987 and 2008 and evaluated with a baseline polysomnography (PSG) and a PSG under NIV. MEASUREMENTS AND RESULTS Sixty patients aged (mean±SD) 48±20 years, with total lung capacity of 57±20% of predicted value, PaO(2) of 62±16 mm Hg and PaCO(2) 54±10 mm Hg, were included. At baseline, total sleep time, sleep efficiency, slow wave and rapid-eye movement (REM) sleep were markedly decreased. Conversely, micro-arousals and stage I sleep (N1) were increased. NIV administered with volume-cycled (53%) or pressure-cycled (47%) ventilators improved daytime PaO(2), PaCO(2), pH and HCO(3)(-). In addition, sleep efficiency, REM sleep, mean and lowest nocturnal SpO(2) increased while stage 1, sleep fragmentation, and oxygen desaturation index decreased significantly. CONCLUSION Hypercapnic ventilatory failure in restrictive disorders profoundly affects sleep quality. NIV can improve not only blood gases, but also sleep architecture.

Response of automatic continuous positive airway pressure devices in a normal subject

To the Editors: Obstructive sleep apnoea (OSA) is a prevalent disease whereby people become unable to breathe when asleep. During sleep the pharyngeal walls are sucked in and collapse completely, causing full (termed apnoea) or incomplete (termed hypopnoea) abolition of airflow. OSA can lead to daytime fatigue and sleepiness, impairment in cognitive functions, motor vehicle crashes, hypertension, cardiovascular disease, stroke and premature deaths [1]. OSA is easily treated with continuous positive pressure applied throughout sleep [2]. The right amount of pressure is determined individually during a titration night, when pressure is gradually increased to keep the airway open to allow for normal sleep and breathing [2]. In 1993 it was postulated that this process of titration could be performed with a stand alone blower equipped with a microprocessor guiding the positive pressure [3]. The idea was to use the blower as a monitoring device identifying abnormal breathing events and react by increasing pressure until disappearance of the abnormal events. The device would then slowly decrease pressure until events reappeared and the pressure would then be increased again [3]. These machines, termed automatic continuous positive airway pressure devices (autoCPAP), were proposed as monitoring or even diagnostic machines [4], as devices used for one night to determine the fixed CPAP level to be used thereafter [5] or even as therapeutic machines to be used every night and to adapt the pressure necessary to keep the pharynx open at all times [6]. When autoCPAP devices were tested in a bench study it was shown that no two devices reacted alike, that many devices did not even recognise the events they were supposed to act upon and that even when recognising the events, many were not able to …

Whole lung lavage in alveolar proteinosis: manual clapping versus mechanical chest percussion.

Alveolar proteinosis is an uncommon lung disease presenting in primary or secondary forms, characterised by surfactant derived proteinous material accumulation within the lungs. The most effective treatment remains whole lung lavage under general anaesthesia. We have recently performed whole lung lavage in a 46-year-old patient with alveolar proteinosis who presented with severe dyspnoea and hypoxia. During the left lung lavage, outwards flow was enhanced at random either by manual clapping or by mechanical chest percussion with a vest airway clearance system. The protein and surfactant protein A concentrations in the 13 successive samples of the left lavage solution showed an exponential decline, not different between manual clapping and chest mechanical percussion. The average concentration of surfactant protein was not different between manual clapping and chest percussion. We conclude that in alveolar proteinosis, manual clapping replacement by mechanical chest percussion during whole lung lavage merits further evaluation.

Home ventilation: need a user support number?

Contemporary homes can include a number of electrical devices aimed at making life easier, such as washing machines, dishwashers and vacuum cleaners. One can also find devices aimed at improving lifestyle, such as exercise bicycles or rowing machines. However, one can also find other types of devices that are aimed at supporting or saving peoples life. These can include continuous positive airway pressure machines, home dialysis machines, oxygen concentrators and home respirators. All these devices have electrical plugs, knobs, switches, light bulbs, LEDs and screens. However, the manipulation of these devices is not at all similar, and the interactions between the devices and the users have quite different meanings. Despite the obvious differences between these machines, it remains true that a malfunctioning washing machine or a malfunctioning respirator will require a similar reaction: call the user support number. Respiratory physicians do not have a long tradition of home life support treatment and every piece of information concerning this issue is worth learning. In the present issue of the European Respiratory Journal , Chatwin et al. 1 present data on the call centre they established to support more than 1,000 patients on home respirators. The Respiratory Unit of the Royal Brompton Hospital (London, UK) serves a vast geographical area. In order to allow patients to reach them, they established a communication protocol based on telephone numbers patients can call day and night in case they need to or they feel they need to. These calls can be made for a number of reasons; from simple concerns such as asking for spare part replacement, to more disturbing ones such alarms coming on during the night or to a respirator becoming noisy all of a sudden, to very serious ones such as a respirator breakdown in a respirator dependent patient. Chatwin et al. …