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KMID : 1004820070080010031
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Journal of Biomedical Research
2007 Volume.8 No. 1 p.31 ~ p.38
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Respiratory Pattern during Maximal Voluntary Ventilation in Patients with Obstructive Ventilatory Defect
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Choe Kang-Hyeon
Shin Yoon-Mi
Lee Kee-Man
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Abstract
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Purpose: Because expiratory airflow limitation is the hallmark physiological change in patients with obstructive ventilatory defect, we wondered whether the patients with obstructive ventilatory defect would show different ventilatory pattern from that of normal persons during maximal voluntary ventilation (MVV).
Materials and Methods: Twelve-second MVV was performed in 38 patients with obstructive ventilatory defect (mean age 61±2 year, mean FEV1/FVC 59±2%) and 51 normal subjects (mean age 55±2 year, mean FEV1/FVC 81±1%). The tidal volumes (TV), respiratory frequency, inspiratory time (Ti), expiratory time (Te), inspiratory flow (IF) and expiratory flow (EF) of the first three and the last three breaths of MVV were analyzed.
Results: The percent predicted value of MVV was lower in obstructive group than in normal group (68±3% vs. 103±3%, p<0.001). Respiratory frequency during the MVV in both groups was similar (62±2 vs. 65±2, p>0.05). The TV and TV/FVC were lower in obstructive group than in normal group (1.04±0.05 L vs. 1.57±0.07 L, p<0.001, 0.35±0.01 vs. 0.49±0.02, p<0.001, respectively). The EF and IF were higher in normal group than in obstructive group (3.43±0.16 L/sec vs 2.47±0.14 L/sec, p<0.001, 3.45±0.17 L/sec vs 2.02±0.14 L/sec, p<0.001, respectively). The EF/IF ratio was higher in obstructive group than in normal group (1.30±0.05 vs. 1.02±0.02, p<0.001). The Te/Ti ratio was lower in obstructive group than in normal group (0.80±0.03 vs. 1.0±0.02, p<0.001).
Conclusion: The patients with obstructive ventilatory defect attributed decreased MVV to decreased TV, not to respiratory frequency. And these patients showed a higher expiratory/inspiratory flow ratio and shorter expiration-inspiration time ratio during MVV than normal subjects did.
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KEYWORD
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Respiratory pattern, Maximal voluntary ventilation, Obstructive lung disease
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