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.

[1]  F. Abboud,et al.  Sympathetic neural mechanisms in obstructive sleep apnea. , 1995, The Journal of clinical investigation.

[2]  B. Langevin,et al.  Clinical Investigations: Sleep and BreathingSide Effects of Nasal Continuous Positive Airway Pressure in Sleep Apnea Syndrome: Study of 193 Patients in Two French Sleep Centers , 1995 .

[3]  P. Howard,et al.  The QTc interval, autonomic neuropathy and mortality in hypoxaemic COPD. , 1995, Respiratory medicine.

[4]  J. Hedner,et al.  Reduction in sympathetic activity after long-term CPAP treatment in sleep apnoea: cardiovascular implications. , 1995, The European respiratory journal.

[5]  W. Flemons,et al.  Sleep apnea and cardiac arrhythmias. Is there a relationship? , 1993, The American review of respiratory disease.

[6]  J Sellgren,et al.  Augmented resting sympathetic activity in awake patients with obstructive sleep apnea. , 1993, Chest.

[7]  A. Pack,et al.  Effects of one night without nasal CPAP treatment on sleep and sleepiness in patients with obstructive sleep apnea. , 1993, The American review of respiratory disease.

[8]  P. Lévy,et al.  Autonomic stress tests in obstructive sleep apnea syndrome and snoring. , 1992, Sleep.

[9]  P. Howard,et al.  Cardiovascular autonomic nerve function in patients with hypoxaemic chronic obstructive pulmonary disease. , 1991, The European respiratory journal.

[10]  A. Graebe.  QTc prolongation measured by standard 12-lead electrocardiography is an independent risk factor for sudden death due to cardiac arrest: Tijssen AA, Roelandt JRTC, Pool J, et al Circulation 83:1888–1894 Jun 1991 , 1991 .

[11]  C Guilleminault,et al.  Changes in the QT interval during obstructive sleep apnea. , 1991, Sleep.

[12]  P C O'Brien,et al.  The effect of ageing on autonomic nervous system function. , 1990, Australian and New Zealand journal of medicine.

[13]  M. Sackner.  Indications and standards for cardiopulmonary sleep studies. , 1989, The American review of respiratory disease.

[14]  J Sellgren,et al.  Is high and fluctuating muscle nerve sympathetic activity in the sleep apnoea syndrome of pathogenetic importance for the development of hypertension? , 1988, Journal of hypertension. Supplement : official journal of the International Society of Hypertension.

[15]  K. Rajagopal,et al.  Overnight nasal CPAP improves hypersomnolence in sleep apnea. , 1986, Chest.

[16]  A J Block,et al.  Indications and standards for cardiopulmonary sleep studies. , 1985, Sleep.

[17]  S. Connolly,et al.  CYCLICAL VARIATION OF THE HEART RATE IN SLEEP APNOEA SYNDROME Mechanisms, and Usefulness of 24 h Electrocardiography as a Screening Technique , 1984, The Lancet.

[18]  D. Ewing.  Cardiovascular reflexes and autonomic neuropathy. , 1978, Clinical science and molecular medicine.

[19]  T. Cooper.  Department of Health, Education, and Welfare. , 1976, Military medicine.

[20]  E. Wolpert.  A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. , 1969 .

[21]  D. Robert,et al.  Obstructive Sleep Apnea and Blood Pressure Elevation: What is the Relationship? , 1993 .

[22]  T. Penzel,et al.  Blood pressure and sleep apnea: results of long-term nasal continuous positive airway pressure therapy. , 1991, Cardiology.

[23]  G. Wallin,et al.  High and Fluctuating Muscle Nerve Sympathetic Activity in the Sleep Apnea Syndrome: A Pathogenetic Mechanism in the Development of Hypertension? , 1988 .

[24]  E. Fletcher,et al.  Urinary catecholamines before and after tracheostomy in patients with obstructive sleep apnea and hypertension. , 1987, Sleep.

[25]  W C Dement,et al.  The sleep apnea syndromes. , 1976, Annual review of medicine.

[26]  A. Rechtschaffen.  A manual of standardized terminology, techniques and scoring system for sleep of human subjects , 1968 .