POSITIVE PRESSURE THERAPY
Section snippets
Mechanism of Action
CPAP systems consist of a blower unit that generates and directs airflow downstream to the patient. The positive pressure is generated by variations in delivered airflow and resistance in the system. When CPAP is delivered by way of a nasal interface, the soft palate seals against the tongue, resulting in a pressurized upper airway (Fig. 1). Pressure is maintained by increasing airflow in response to small leaks, involving the mask or mouth. The collapsible region of the upper airway is
BILEVEL POSITIVE AIRWAY PRESSURE
Previous work by a number of investigators75, 79, 85, 94 has shown that upper airway resistance increases during expiration despite the absence of negative intrapharyngeal pressure accompanying inspiration. Sanders et al79 subsequently speculated that the instability of the upper airway during expiration is the initial event in the sequence leading to obstructive apnea. Mahadevia et al49 further substantiated that concept by demonstrating that apnea frequency could be reduced by the application
VARIABLE (AUTOTITRATING) CPAP
The pressure required to stabilize the upper airway during sleep is influenced by several factors, including body position, sleep stage, sleep deprivation, sedatives, and alcohol. * It would appear to be theoretically advantageous to use a positive-pressure device that would raise and lower the pressure delivered in response to those conditions. A number of positive-pressure devices that provide variable
SPECIAL CONSIDERATIONS
Patients with OSDB treated with positive airway pressure should be re-evaluated at regular intervals to reinforce the importance of continued treatment, assess compliance and response to treatment, and address any side effects or complications of the therapy. In patients who complain of persistent daytime sleepiness, an objective evaluation of machine use should be obtained prior to repeat polysomnography. That can be accomplished easily by securing an hour “meter read” of machine use. Most
FUTURE DIRECTIONS
Considerable advances have been made in our understanding of positive airway pressure therapy for OSDB. A wide variety of masks are available that improve patient comfort and acceptance of the interface. The current generation of CPAP and bilevel positive airway pressure systems is relatively quiet, highly portable, and durable. Compliance should be monitored objectively in all patients treated chronically with positive airway pressure. As is the case with any chronic disease, it is clear that
References (111)
- et al.
Management of obstructive sleep apnea syndrome in the home: The role of portable sleep apnea recording
Chest
(1993) - et al.
Effect of flurazepam on sleep-disordered breathing and nocturnal oxygen desaturation in asymptomatic subjects
Am J Med
(1982) Self-reported use of CPAP and benefits of CPAP therapy
Chest
(1996)- et al.
Periodic leg movements in sleep following treatment of obstructive sleep apnea with nasal continuous positive airway pressure
Chest
(1989) - et al.
Mortality and apnea index in obstructive sleep apnea: Experience in 385 male patients
Chest
(1988) - et al.
Pneumocephalus associated with nasal continuous positive airway pressure in a patient with sleep apnea syndrome
Chest
(1989) - et al.
Recovery of alertness after CPAP in apnea
Chest
(1989) - et al.
Effect of sleep position on sleep apnea and parafunctional activity
Chest
(1986) - et al.
Oral–nasal continuous positive airway pressure as a treatment for obstructive sleep apnea
Chest
(1994) - et al.
Overnight nasal CPAP improves hypersomnolence in sleep apnea
Chest
(1986)
Acceptance of CPAP therapy for sleep apnea
Chest
Nasal CPAP effect on patterns of sleep apnea
Chest
Obstructive sleep apnea treated by independently adjusted inspiratory and expiratory positive airway pressures via nasal mask
Chest
Patient compliance with nasal CPAP therapy for sleep apnea
Chest
CPAP therapy via oro-nasal mask for obstructive sleep apnea
Chest
Conjunctivitis from nasal CPAP apparatus
Chest
Massive epistaxsis from nasal CPAP therapy
Chest
Benefit of nasal CPAP in obstructive sleep apnea is due to positive pharyngeal pressure
Sleep
Effects of continuous positive airway pressure on upper airway and respiratory muscle activity
J Appl Physiol
Increase in intraocular pressure during nasal CPAP
Chest
Arousal producing leg movements in sleep disordered breathing pre and post treatment with positive airway pressure
Sleep Res
Effect of lung inflation on pulmonary resistance during NREM sleep
Am Rev Respir Dis
Automatic control of airway pressure for treatment of obstructive sleep apnea
IEEE
Effect of ethanol on the efficacy of nasal continuous positive airway pressure as a treatment for obstructive sleep apnea
Chest
Feasibility of a self-setting CPAP machine
Sleep
Nasal continuous positive airway pressure treatment: Current realities and future
Sleep
Obstructive sleep apnea reversed by increased lung volume?
Eur J Respir Dis
Cumulative effects of sleep restriction on daytime sleepiness
Psychophysiology
Effect of sleep position on sleep apnea severity
Sleep
Compliance with nasal CPAP can be improved by simple interventions
Sleep
Neuropsychologic symptoms in obstructive sleep apnea improve after treatment with nasal continuous positive airway pressure
Chest
Use of in vivo desensitization to treat a patient's claustrophobic response to nasal CPAP
Sleep
Compliance with CPAP therapy in patients with the sleep apnoea/hypopnoea syndrome
Thorax
Comparison of cold passover versus heated humidification during nCPAP therapy
Am J Respir Crit Care Med
Long-term compliance to continuous positive airway pressure therapy (nCPAP) set up during a split-night polysomnography
Sleep
Sleep apnea and body position during sleep
Sleep
Progressive improvement of apnea index and ventilatory response to CO2after tracheostomy in obstructive sleep apnea syndrome
Am Rev Respir Dis
Sleep-disordered breathing and hypertension: Past lessons, future directions
Sleep
Obstructive sleep apnea syndrome and tracheostomy: Long-term follow-up experience
Arch Intern Med
Comparison of cannula and mask systems for administration of nasal continuous positive airway pressure
Sleep Res
Continuous nasal positive airway pressure with a mouth leak: Effect on nasal mucosal blood flux and nasal geometry
Thorax
Residual effect of nCPAP applied to part of the night in patient with obstructive sleep apnoeas
Eur Respir J
Predicting nasal continuous positive airway pressure
Am J Respir Crit Care Med
Treatment of obstructive sleep apnea with nasal continuous positive airway pressure patient compliance, perception of benefits, and side effects
Am Rev Respir Dis
Lung volume dependence of cross-sectional area in patients with obstructive sleep apnea
Am Rev Respir Dis
Single night studies in obstructive apnea
Sleep
Alcohol, snoring and sleep apnea
J Neurol Neurosurg Psychiatr
Reversal of central sleep apnea using nasal CPAP
Chest
Unattended continuous positive pressure titration. Clinical relevance and cardiorespiratory hazards of the method
Am J Respir Crit Care Med
Effects of one night without nasal CPAP treatment on sleep and sleepiness in patients with obstructive sleep apnea
Am Rev Respir Dis
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Address reprint requests to Patrick J. Strollo, Jr, MD University of Pittsburgh School of Medicine Division of Pulmonary, Allergy and Critical Care Medicine 3459 Fifth Avenue, Suite S-643 Pittsburgh, PA 15213
Supported in part by Department of Veterans Affairs Medical Center and NHLBI Training Grant NHLBI2T32HL0756311A2.