Improvement in Obstructive Sleep Apnea in the Supine “Knees-Up” Position

We report a 38-year-old man with obstructive sleep apnea whose sleep-disordered breathing was substantially reduced by sleep in the supine, “knees-up” position, relative to his sleep in the customary supine, “knees-down” position. No obvious anatomic or pathophysiologic alterations explained this phenomenon. The effect was reproducible in the patient 4 years later. Potential mechanisms underlying such improvement, including alterations in upper airway/lung volume dependence and venous supply to upper airway vasculature, are discussed. This manipulation could be an important adjunctive treatment for a subset of obstructive sleep apnea patients demonstrating such an effect.

Obstructive sleep apnea - body position - sleep-disordered breathing

REFERENCES

• 1 Cartwright R D, Diaz F, Lloyd S. The effects of sleep posture and sleep stage on apnea frequency.  Sleep. 1991;  14 351-353
• 2 Oksenberg A, Silverberg D S, Arons E et al.. Positional vs nonpositional obstructive sleep apnea patients: anthropomorphic, nocturnal polysomnographic, and multiple sleep latency data.  Chest. 1997;  112 629-639
• 3 Pevernagie D A, Stanson A W, Sheedy II P F et al.. Effects of body position on the upper airway of patients with obstructive sleep apnea.  Am J Respir Crit Care Med. 1995;  152 179-185
• 4 Taber C W. Taber's Cyclopedic Medical Dictionary Including a Digest of Medical Subjects: Medicine, Surgery, Nursing, Dietetics, Physical Therapy. 6th ed. Philadelphia, PA; FA Davis Co 1955: D40
• 5 Boren H G, Kory R C, Syner J C. The Veterans Administration-Army cooperative study of pulmonary function: II. The lung volume and its subdivisions in normal men.  Am J Med. 1966;  41 96-114
• 6 Craig Jr A B. Effects of position on expiratory reserve volume of the lungs.  J Appl Physiol. 1960;  15 59-61
• 7 Hoffstein V, Zamel N, Phillipson E A. Lung volume dependence of pharyngeal cross-sectional area in patients with obstructive sleep apnea.  Am Rev Respir Dis. 1984;  130 175-178
• 8 Series F, Cormier Y, Lampron N et al.. Influence of lung volume in sleep apnoea.  Thorax. 1989;  44 52-57
• 9 Series F, Marc I. Influence of lung volume dependence of upper airway resistance during continuous negative airway pressure.  J Appl Physiol. 1994;  77 840-844
• 10 Shepard Jr J W, Pevernagie D A, Stanson A W et al.. Effects of changes in central venous pressure on upper airway size in patients with obstructive sleep apnea.  Am J Respir Crit Care Med. 1996;  153 250-254
• 11 Oksenberg A, Silverberg D S, Arons E et al.. The sleep supine position has a major effect on optimal nasal continuous positive airway pressure: relationship with rapid eye movements and non-rapid eye movements sleep, body mass index, respiratory disturbance index, and age.  Chest. 1999;  116 1000-1006