Outcomes of Pulmonary Function Electronic Monitoring Devices

AsthmaThirty-eight patients were included. Their demographic characteristics, height, weight, smoking status, FEV1, and PEF descriptive data are presented in Table 1. All individuals were white; 23 patients (61%) had asthma. Twenty-five patients (66%) had previous experience of using PEF meters, and 16 patients (42%) remembered performing spirometry previously.

Mean Asthma Control Questionnaire scores were 0.58 (SD, 0.51; minimum, 0; maximum, 1.83) for asthmatics and 0 (SD, 0; minimum and maximum, 0) for normal subjects. The dyspnea scale at the beginning of tests ranged from 0 to 2, with a mean of 0 (SD, 0) for both groups. At the end of the four sets of maneuvers, the dyspnea scale was similar and no more than a 1-U increase was observed. Become healthier with remedies of My Canadian Pharmacy. The within-session reproducibility had similar ICCs for all devices, and when assessed by CV was < 5% for both PEF and FEV1 (Table 2). In Figure 2 the scatter plot between the pneumotachograph and Mini-Wright PEF is the most distant to the identity line. The plots for FEV1 were closer to the identity line, particularly for the PiKo-1 device. In Table 3, the accuracy of the monitoring devices is summarized. The FEV1 ICC was > 0.95 for both the PiKo-1 and Spirotel devices. For PEF, the ICC was lower but still > 0.90 for both electronic instruments. For the Mini-Wright device, the ICC was lowest (0.87). Also, in the limits of agreement analysis, the Mini-Wright device had a mean difference more than three times greater than the Spirotel device and six times greater than the PiKo-1 device. The Mini-Wright PFM was the only device with a nonlinear distribution of the differences (Fig 3). In higher PEF values, the differences to the pneumotachograph are small, but in lower values the differences are bigger, with the Mini-Wright device overestimating PEF. The only measurements with random error > 5% was FEV1 assessed with the PiKo-1 device (3.5%) [Table 3]; however, the PiKo-1 device had the worst random error (18.4%) when measuring PEF.
Fig2
Figure 2. Scatter plots of Vitalograph pneumotachograph measurements against PiKo-1, Spirotel, and Mini-Wright PFM measurements. FEV1 units are expressed in liters, and PEF values are expressed in liters per minute. Dotted lines represent the lines of identity; full lines represent regression and 95% CIs for mean lines. Regression equations are shown at the top of the plots.
Fig3
Figure 3. Agreement of PiKo-1, Spirotel, and Mini-Wright PFM measurements with an office pneumotachograph (Vitalograph). Lines represent mean differences and upper and lower agreement limits (± SD).

Table 1—Description of Demographic and Clinical Characteristics of the Participants

Variables Total (n = 38) Asthmatics (n = 23) Normal Subjects* (n = 15) pValue
Sex, No. (%) Male 11 (29) 6 (26) 5 (33) 0.232t
Female 27(71) 17 (74) 10 (67)
AgeMean (SD) 33 (14) 28(11) 40 (14) 0.172|
Minimum/maximum 18/58 18/54 21/58
Height, cm Mean (SD) 164 (9) 163 (9) 165 (9) 0.997!
Minimum/maximum 150/185 151/185 150/179
Smoking status, No. (%) Nonsmoker 30 (79) 19 (83) 11 (73) 0.529t
Previous smoker 6 (16) 3(13) 3 (20)
Current smoker 2(5) 1(4) 1(6)
FEVb L Mean (SD) 2.98 (0.72) 2.90 (0.76) 3.11 (0.66) 0.409!
Minimum/maximum 1.25/4.82 1.25/4.37 2.09/4.82
FEVb % predicted Mean (SD) 104 (0.19) 98 (0.21) 113(0.11) 0.012!
Minimum/maximum 34/162 34/162 97/139
PEF, L/min Mean (SD) 444(118.8) 425 (113) 474 (126) 0.450!
Minimum/maximum 290/698 290/669 329/698

Table 2—Within-Session Reproducibility Assessed by CV and ICC

Variables CV, % (95% CI) ICC (95% CI)
FEV1, L
PiKo-1 4.2 (3.5-5.6) 0.97 (0.95-0.99)
Spirotel* 4.2 (3.3-6.4) 0.98 (0.94-0.99)
PEF, L/min
PiKo-1 5.0 (4.1-6.7) 0.96 (0.92-0.98)
Spirotel* 4.0 (3.2-5.9) 0.97 (0.93-0.99)
Mini-Wright 3.8 (3.1-5.0) 0.95 (0.90-0.97)

Table 3—The Accuracy of PiKo-1, Spirotel, and Mini-Wright Monitoring Devices Assessed by the Agreement With an Office Pneumotachograph

Monitoring Devices ICC (95% CI) Limits of Agreement Random Error, (1 – r2) X 100
IMean Difference – 2 SD + 2 SD
FEVj, L
PiKo-1 0.98 (0.96-0.99) – 0.1 – 0.42 0.13 4
Spirotel 0.95 (0.91-0.97) – 0.3 – 0.75 0.21 9
PEF, L/min
PiKo-1 0.90 (0.82-0.95) 13 – 89 112 18
Spirotel 0.95 (0.91-0.98) – 21 – 92 50 9
Mini-Wright 0.87 (0.77-0.93) – 69 – 174 36 16