The Bronchial Response, but not the Pulmonary Response to Inhaled Methacholine Is Dependent on the Aerosol Deposition Pattern: Results
The data were expressed by mean values and SD. The statistical analyses used were Mann-Whitney U test, Wilcoxon matched-paired test, and Spearmans correlation test. A p value of <0.05 was considered to indicate statistical significance.
Baseline Conditions on the Two Experimental Days
Before challenge, sGaw was within the predicted normal values in five of the patients on both study days, and there were no significant interday differences in any of the patients. Narrow unimodal distributions of the ventilation and perfusion were recorded in 10 of 16 measurements performed at baseline the two study days. The Va/Q distributions were mildly abnormal with bimodal distributions of the perfusion in six of the measurements. There were no statistically significant differences in the log SDQ or log SDV values measured at baseline on the twc separate experimental days. Although there were minor decrements from the predicted normal value of the arterial P02 in three of the baseline tests, there were no significant interday differences, and the decrements were present independently of the baseline values of sGaw or the descriptors of Va/Q mismatch. canadian health&care mall
Penetration Index
There was a tenfold difference in penetration index after the two separate experiments, as suggested by the two sets of values obtained after central and peripheral airway deposition (0.40 ± 0.14 and 3.88 ± 1.22, respectively).
Effect of Methacholine
Central Airway Deposition of Methacholine: A marked and transient decrease in sGaw was seen after inhalation of methacholine (p<0.01, Table 1). The maximal responses measured by plethysmography were recorded immediately after the challenge, and on an average there was a fall in the sGaw values from baseline of 0.96 ±0.31 (sxkPa), which on an average corresponded to 35 percent of the baseline levels.
Table 1—Lung Function and Arterial Blood Gases Before and at Various Time Points After Bronchial Challenge With Nebulized Methacholine
Baseline | Postchallenge | |||
5 min | 30 min | 120 min | ||
sGaw | ||||
Centr | 1.58 (0.63) | 0.60 (0.37) | 1.17 (0.97) | 1.29 (0.92) |
Periph | 1.52 (0.64) | 0.85 (0.48) |
1.05 (0.72) | 1.50 (0.92) |
Log SDQ | ||||
Centr | 0.51 (0.21) | 0.83 (0.28) | 0.86(0.14)1 | 0.71 (0.22) |
Periph | 0.58 (0.25) | 0.88 (0.30) | 0.94 (0.32) | 0.84 (0.26) |
Log SDV | ||||
Centr | 0.46 (0.16) | 0.54 (0.19) | 0.52 (0.15) | 0.44(0.13) |
Periph | 0.49 (0.12) | 0.55 (0.18) | 0.61 (0.17) | 0.54 (0.11) |
РаОг | ||||
Centr | 13.8(1.6) | 10.8 (1.3) | 12.2 (1.9) | 13.2 (1.7) |
Periph | 13.6(1.9) | 11.2(1.6) | 12.2 (1.9) | 12.8 (2.6) |
PaC02 | ||||
Centr | 4.75 (0.70) | 4.87 (0.70) | 4.69 (0.72) | 4.76 (0.65) |
Periph | 4.84 (1.9) | 4.96 (0.52) | 4.67 (0.74) | 5.01 (0.26) |