Effect of Disodium Cromoglycate on Ventilation and Gas Exchange During Exercise in Asthmatic Children With a Postexertion FEVi Fall Less Than 15 Percent: Discussion

Aug-28-2014

Exercise testing results are summarized in Table 3. No differences were found in the cardiorespiratory and metabolic parameters between tests A and B. In particular, we found no difference in the kinetics of Ve between tests A and В (ANOVA, p = not significant; Table 4).
In the present study, we found that preexercise inhaled DSCG reduces Ve and V02 during incremental exercise in asthmatic children without a substantial reduction of FEVi, ie, less than 15 percent from baseline, after the end of exercise, as compared with a test without premedication. As the FEVi fall cutoff after exercise, we chose 15 percent because this is the conventional criterion to detect EIA and prescribe premedication.” Values of Ve and V02 were not different at rest between baseline and the premedicated test, but throughout the exercise these parameters were significantly lower under treatment conditions at comparable work rates (Fig 1, 2).

To evaluate a possible action of DSCG on normal airways, we also studied the effect of this drug in a group of healthy children who underwent the same exercise protocol, finding that DSCG does not affect gas exchange and ventilation during exercise in healthy subjects. In this manner a possible bias, ie, the presence of an unexpected effect also on normal airways, has been ruled out, confirming that DSCG has no ergogenic effects in healthy individuals website asthma inhaler.
In spite of the demonstrated effectiveness of several drugs in preventing EIA, surprisingly little is known about their effect on ventilation and gas exchange during exercise. In a previous study on asthmatic children with EIA (mean percentage of fall in FEVi of 33 percent), we noted that premedication with DSCG was associated with a reduction in ventilation and EC of running. In the present study, DSCG was administered to a group of asthmatic children without clinical and spirometric evidence of substantial bronchoconstriction at the end of an unpremedicated exercise.

Table 3—Exercise Testing Results in Healthy Children

Test A (Baseline) Test В (DSCG) Probability Value f
Resting V02, ml-min – kg) 3.6± 1.7 3.4± 1.8 NS
Resting VCO2, ml-min – kg 3.8± 1.9 3.4± 1.7 NS
Resting Ve, L-min 4.7±3.0 4.5±3.0 NS
AT,O2 ml-min – kg 27.2 ±4.4 27.0 ±6.5 NS
Peak V02,ml-min-kg 38.0 ±10.2 38.3 ±10.7 NS
VEmax,L-min 47.8 ±25.0 48.4 ±25.0 NS
Running time, min 8.1 ±1.9 7.6± 1.9 NS
Maximal HR, beats per minute 192.6 ±6.3 195.1 ±7.4 NS

Table 4—Minute Ventilation in Test A (Without Premedication) and in Test В (With DSCG) in Healthy Children

Running Time (min) Test A (Baseline) Test В (DSCG)
At rest 4.7 ± 1.3 4.5± 1.1
1 19.3 ±2.4 20.0 ±2.8
2 27.0 ±3.7 28.4±3.8
3 32.7 ±4.9 32.5±4.7
4 32.3 ±4.6 34.6±5.4
5 34.1 ±5.6 35.6±5.4
6 46.1 ±7.0 47.7 ±7.2
7 49.8 ±8.3 53.1 ±7.9
8 53.3 ±8.3 55.9 ±8.0