Increased resting airway tone and airway hyper responsiveness have been described in patients with cervical spinal cord injury. These conditions are attributed to unopposed cholinergic bronchoconstrictor activity from loss of sympathetic innervation of the airway. Previous studies were spirometry based. Plethysmographic assessment of baseline airway resistance has not been previously reported. Our objective was to determine the resting airway caliber in a population of spinal cord injury patients and to better define the participation of cholinergic innervation in this condition.
We studied 18 tetraplegic patients and 24 healthy control subjects by measuring airway conductance, before and after inhaled ipratropium bromide.
The average baseline airway specific conductance was less in tetraplegic patients than control group, 0.25and 0.50cm H2O/L/s/L (P =0.001), respectively. All patients had improved post bronchodilator specific conductance greater than 35% whereas only half of the controls exhibited improvement (P less than 0.05). The percent variation for tetraplegics increased an average 235% versus only 31% for controls (P<0.001).CONCLUSIONS: Cervical spinal cord injury patients have a reduced baseline airway specific conductance compared to controls.
Marked improvement in conductance occurs after an inhaled anticholinergic drug in tetraplegic patients.
T.A. Horan, None.