Lung volume-related changes in the pharyngeal area of obese females with and without obstructive sleep apnoea

The majority of male patients with obstructive sleep apnoea (OSA) have an abnormal pharyngeal structure and function, with episodic complete airway occlusion during sleep. Since OSA is less common in females than in males, it is possible that other abnormalities are active in female patients with OSA. Consequently, we measured pharyngeal area and its lung volume-related changes (LVRC) from functional residual capacity (FRC) to residual volume (RV) in overweight females, 14 with OSA and 14 without OSA. Pharyngeal areas were measured using the acoustic reflection technique. While there were no significant differences in pharyngeal area between the OSA and control groups at either FRC (mean +/- SD, 3.49 +/- 0.46 cm2 vs 3.08 +/- 0.63 cm2) or RV (2.86 +/- 0.47 cm2 vs 2.67 +/- 0.49 cm2), the reduction in pharyngeal area between FRC and RV was significantly greater in the OSA group (0.63 +/- 0.23 cm2 vs 0.33 +/- 0.32 cm2, p less than 0.05). Furthermore, although the expiratory reserve volume (ERV) was not significantly different between the two groups (0.4 +/- 0.2 l vs 0.4 +/- 0.3 l), LVRC, defined as the reduction in pharyngeal area normalized by ERV, was significantly higher in the females with OSA than in the non-apnoeic controls (2.68 +/- 2.24 cm2.l-1 vs 1.17 +/- 1.23 cm2.l-1, p less than 0.02). We conclude that females with OSA have abnormal pharyngeal mechanics similar to males with OSA.

This article has been cited by other articles:

				D. J. Eckert and A. Malhotra Pathophysiology of Adult Obstructive Sleep Apnea Proceedings of the ATS, February 15, 2008; 5(2): 144 - 153. [Abstract] [Full Text] [PDF]

				R C Heinzer, M L Stanchina, A Malhotra, A S Jordan, S R Patel, Y-L Lo, A Wellman, K Schory, L Dover, and D P White Effect of increased lung volume on sleep disordered breathing in patients with sleep apnoea Thorax, May 1, 2006; 61(5): 435 - 439. [Abstract] [Full Text] [PDF]

				C. M. Ryan and T. D. Bradley Pathogenesis of obstructive sleep apnea J Appl Physiol, December 1, 2005; 99(6): 2440 - 2450. [Abstract] [Full Text] [PDF]

				T. Ishikawa, S. Isono, J. Aiba, A. Tanaka, and T. Nishino Prone Position Increases Collapsibility of the Passive Pharynx in Infants and Small Children Am. J. Respir. Crit. Care Med., September 1, 2002; 166(5): 760 - 764. [Abstract] [Full Text] [PDF]

				V. Mohsenin Gender Differences in the Expression of Sleep-Disordered Breathing : Role of Upper Airway Dimensions Chest, November 1, 2001; 120(5): 1442 - 1447. [Abstract] [Full Text] [PDF]

				G. PILLAR, A. MALHOTRA, R. FOGEL, J. BEAUREGARD, R. SCHNALL, and D. P. WHITE Airway Mechanics and Ventilation in Response to Resistive Loading during Sleep . Influence of Gender Am. J. Respir. Crit. Care Med., November 1, 2000; 162(5): 1627 - 1632. [Abstract] [Full Text]