Bronchial Hyperresponsiveness After Cervical Spinal Cord Injury: Results

May-30-2014

Bronchial Hyperresponsiveness After Cervical Spinal Cord Injury: ResultsBaseline spirometry revealed no evidence of obstruction (Table 1). All patients demonstrated hyperresponsiveness to methacholine (Table 2). Values of FEVi and FVC at baseline and after provocation were 3.06 ±0.61 (SD) L vs 1.91 ±0.60 L (p=0.002), and 3.46 ±0.75 L vs 2.73 ±0.69 L (p=0.062), respectively. Percentage predicted values for FEVi and FVC before and after methacholine challenge were 71.9 ±13.9 L vs 45.0 ±14.5 L (p= 0.002), and 62.5 ± 13.8 L vs 49.4 ± 12.6 L (p=0.067), respectively. Baseline values of FEVi/FVC ratio (percent) decreased after bronchoprovocation from 89.0 ± 6.0 to 71.6 ± 18.8 (p=0.026). Seven of the eight subjects experienced a feeling of chest tightness after inhalation of the concentration of methacholine producing a greater than 20 percent fall in FEVi. Administration of nebulized metaproterenol sulfate resulted in resolution of symptoms and return to baseline FEVi in all patients. No correlation was observed between airway reactivity (PC20) and either the level of cervical lesion or baseline FEVi. The baseline FVC did correlate with the level of the lesion.
Four of the eight subjects underwent repeat methacholine challenge testing after inhalation of ipratropium bromide. Pretreatment with inhaled ipratropium bromide (72 pg) completely blocked the response to methacoline in all subjects (Table 2). The mean PC20 without and with ipratropium bromide was 1.42 ±1.61 mg/ml vs more than 25 mg/ml (p<0.0001). We have demonstrated the presence of bronchial hyperreactivity to methacholine in a group of patients with chronic, traumatic lesions of the cervical spinal cord. Pretreatment with ipratropium bromide resulted in the blockade of methacholine hyperresponsiveness. canadianneighborpharmacy.com

Human airway reactivity has been examined in various environments of altered pulmonary innervation. Pharmacologic blockade of vagal tone with atropine and ipratropium bromide produces bron-chodilation, thereby demonstrating the presence of resting cholinergic bronchoconstrictor tone.” Bronchoprovocation testing in patients after heart-lung or double-lung transplantation, and hence, with resultant total pulmonary denervation, has revealed hyperresponsiveness to methacholine, presumably on the basis of denervation hypersensitivity of airway muscarinic receptors.”

Table 2—Results of Methacholine Challenge Testing

Patient FEVi, L FVC, L FEVi/FVC Ratio % Fall FEVi PC20, mg/ml PC20 (mg/ml) After Ipratropium Bromide
Prechallenge Postchallenge Prechallenge Postchallenge Prechallenge Postchallenge
1 3.82 (86) 2.51 (56) 4.43 (77) 3.59 (62) 0.86 0.70 34 0.11 >25
2 3.88 (89) 0.83 (19) 4.40(79) 2.66 (48) 0.88 0.31 79 0.30 >25
3 2.27 (48) 1.27 (27) 2.28 (37) 1.30 (21) 1.00 0.98 44 0.36
4 2.48 (68) 1.66(45) 2.91 (62) 2.38 (51) 0.85 0.70 33 4.96 >25
5 3.00 (72) 2.26 (55) 3.69 (66) 3.20(57) 0.81 0.71 25 0.97 >25
6 3.47 (84) 2.43 (59) 3.77 (69) 3.15 (58) 0.92 0.77 30 0.99
7 2.86 (64) 2.28 (51) 3.04 (51) 2.83 (48) 0.94 0.81 20 2.49
8 2.68 (64) 2.01 (48) 3.13 (59) 2.69 (50) 0.86 0.75 25 1.17