Chest wall kinematics and respiratory muscle action in ankylosing spondylitis patients

Abstract

No direct measurements of the pressures produced by the ribcage muscles, the diaphragm and the abdominal muscles during hyperventilation have been reported in patients with ankylosing spondylitis. Based on recent evidence indicating that abdominal muscles are important contributors to stimulation of ventilation, it was hypothesised that, in ankylosing spondylitis patients with limited ribcage expansion, a respiratory centre strategy to help the diaphragm function may involve coordinated action of this muscle with abdominal muscles.In order to validate this hypothesis, the chest wall response to a hypercapnic/hyperoxic rebreathing test was assessed in six ankylosing spondylitis patients and seven controls by combined analysis of: 1) chest wall kinematics, using optoelectronic plethysmography, this system is accurate in partitioning chest wall expansion into the contributions of the ribcage and the abdomen; and 2) respiratory muscle pressures, oesophageal, gastric and transdiaphragmatic (Pdi); the pressure/volume relaxation characteristics of both the ribcage and the abdomen allowed assessment of the peak pressure of both inspiratory and expiratory ribcage muscles, and of the abdominal muscles.During rebreathing, chest wall expansion increased to a similar extent in patients to that in controls; however, the abdominal component increased more and the ribcage component less in patients. Peak inspiratory ribcage, but not abdominal, muscle pressure was significantly lower in patients than in controls. End-inspiratory Pdi increased similarly in both groups, whereas inspiratory swings in Pdi increased significantly only in patients. No pressure or volume signals correlated with disease severity.The diaphragm and abdominal muscles help to expand the chest wall in ankylosing spondylitis patients, regardless of the severity of their disease. This finding supports the starting hypothesis that a coordinated response of respiratory muscle activity optimises the efficiency of the thoracoabdominal compartment in conditions of limited ribcage expansion.

The Effect of Upper Chest Wall Restriction on Diaphragmatic Function

“…In previous research into ventilation in ankylosing spondylitis, diaphragm contribution was estimated by the ratio between the chest wall and abdominal wall motion which was measured by magnetometer 3) , optoelectronic plethysmography 5) , and laser techniques 4) . These methods are indirect assessments of diaphragmatic function.…”

“…It was reported recently that in ankylosing spondylitis, the upper chest wall motion is reduced while there is a normal range of lower chest wall and abdominal motion 4) . It has been indicated that ankylosing spondylitis patients are able to compensate for their limited upper chest wall motion by increasing diaphragm motion 4,5) . However, it is unclear whether in healthy subjects such a compensatory breathing pattern is induced by upper rib cage restriction.…”

Estimating Breathing Movements of the Chest and Abdominal Wall Using a Simple, Newly Developed Breathing Movement-Measuring Device

“…Loss of chest and abdominal wall mobility affects respiratory function and, in some cases, results in respiratory complications. A loss in mobility may be due to various factors such as aging, 1,2 scoliosis, 3,4 thoracoabdominal surgery, 5,6 ankylosing spondylitis, 7 and other chest wall diseases. 8 Therefore, chest and abdominal mobility assessments should be performed in a variety of clinical settings.…”

Investigation of Lung Involvement in Connective Tissue Disorders

“…Ribcage expansion is reduced but the abdominal expansion is preserved [248] as well as the diaphragmatic movement avoiding hypercapnic 'ventilator pump' failure [232] .…”

“…Men are far more frequently affected than women (16: 1) and more than 90% of Caucasians with the disease possess the HLA-B27 antigen [230] . Respiratory manifestations ( table 2 ) in ankylosing spondylitis are not uncommon and affect mainly the thoracic cage, the lungs in the form of an apical fibrobullous disease and obstructive sleep apnea syndrome (OSAS) [231][232][233][234][235][236][237][238][239][240][241][242][243][244][245][246] (see online suppl. table 7).…”