The MW/FEV, Ratio in Normal and Asthmatic Subjects: Results

9 Oct
2014

Results
Spirometric Tests
Compared with results in the asthmatic subjects, FEVi, FEV/FVC and MW were higher in the normal subjects (Table 1). The M W/FE V! ratio was also higher in the normal subjects. Using one-tailed and two-tailed analyses, the lower 95 percent confidence limits for a normal MW/FEVi were 34.8 and 33.0, respectively; 13/40 and 9/40 stable asthmatic subjects had MW/ FEVi values below these confidence limits. There was a significant correlation between MW/FEV! and age in the normal subjects (r = 0.70, p<0.001) (Fig 1); age and MW/FEV! also correlated significantly in the group of stable asthmatic subjects (r = 0.37, p<0.02). Correlations between spirometric or SGAW results and MW/FEV, were neither high nor statistically significant. mycanadianpharmacy

Effects of Deep Inspiration
In the normal group, SGawDI was higher than SGaw in 15 of 20 subjects; in contrast, SGawDI exceeded SGaw in only 19 of 40 asthmatic subjects. In the normal individuals, SGawDI was significantly higher than SGaw whereas SGawDI and SGawMW did not differ significantly (Table 2). In the stable asthmatic subjects, SGaw and SGawDI did not differ significantly but SGawDI was significantly higher than SGawMW (Table 2). In the normal subjects, thoracic gas volume (Vtg) at functional residual capacity averaged 2.66 ±0.49, 2.66 ±0.50, and 2.68 ±0.54 before DI, after DI, and after MW; in the asthmatic subjects, corresponding values were 3.04 ±0.59, 3.02 ±0.59, and 3.05 ±0.59.

Table 1 — Routine Pulmonary Function Results (Mean±SD)

Normal IndividualsAsthmatic Subjects
n2040
Age (years)37 ±1537 ±13
FEV, (L)3.5± 1.12.7±0.9t
FEV, (% predicted)99± 1781 ± 211*
FEV/FVC (%)83±869± lit
MW (L/min)152 ±38103±37t
MW/FEV,(mirr)44.5±5.938.2±6.3t

Table 2 — Specific Conductance Results Before and After Deep Inspiration and Maximal Voluntary Ventilation

Normal IndividualsAsthmatic Subjects
n2040
SGaw (cm s~‘)0.223 ±0.0600.121 ±0.074$
SGawDI (cm ~ s ‘)0.231 ±0.061t0.121 ±0.073$
SGawMW (cm s~l)0.229 ±0.06110.115± 0.068$§
SGawDI/SGawMW1.01 ±0.041.05 ±0.09$

 

Figure 1. Relationship between MW/FEV, and age (y = 0.28x+ 34.1) in normal subjects. The correlation is positive (r = 0.70) and highly statistically significant (p<0.001).

Figure 1. Relationship between MW/FEV, and age (y = 0.28x+ 34.1) in normal subjects. The correlation is positive (r = 0.70) and highly statistically significant (p<0.001).

top