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خرید پکیج
تعداد آیتم قابل مشاهده باقیمانده : 3 مورد
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Characteristic features of patients with ventilatory limitation to exercise, by etiology

Characteristic features of patients with ventilatory limitation to exercise, by etiology
  Baseline PFTs Exercise flow-volume loops Oxygenation Ventilatory efficiency Post-exercise spirometry Other features
Normal Normal Increasing air movement
  • VT should at least double
  • VT increases up to 70% of resting IC
 No significant change with exercise
  • O2Sat >96% at rest, decreases <3% w/exercise
  • Peak A-a O2 difference <35
 Normal ventilatory efficiency
  • Ventilatory reserve ≥30%
  • VE-VCO2 slope <32
  • VE/VCO2 nadir <34
  • PETCO2 >36 at rest and at anaerobic threshold
  • VD/VT <0.4 at rest, falls with exercise
 Normal RR increases smoothly at low workloads; max RR usually <50/min
Obstructive disease Obstructed
  • Typically normal/↓FEV1
  • ↓FEV1/FVC
 Exercise flow limitation
  • Decrease in IC
  • Flow limitation in expiration
  • Suboptimal VT increase
 Possible exertional hypoxemia
  • O2Sat may decrease at rest and w/exercise
  • Peak A-a gradient may be >35
  • Oxygenation deficits more likely w/emphysema
 Reduced ventilatory efficiency
  • Ventilatory reserve <30%
  • VE-VCO2 slope >32
  • VE/VCO2 nadir >34
  • PETCO2 may be <36 at rest
  • PETCO2 may increase more than normal w/exercise
  • VD/VT may not decrease with exercise
 Decrease by >10 to 15% indicates EIB Wheezing; RR may plateau early in exercise
Restrictive disease Restricted
  • ↓FEV1, ↓FVC
  • Nl FEV1/FVC, ↓TLC
 Impaired increase in tidal volume
  • Suboptimal VT increase
  • VT ≥85% of resting IC
 Possible exertional hypoxemia
  • O2Sat may decrease at rest and w/exercise
  • Peak A-a O2 difference may be >35
  • Oxygenation deficits more likely with ILD than neuromuscular disease
 Reduced ventilatory efficiency
  • Ventilatory reserve <30%
  • VE-VCO2 slope >32
  • VE/VCO2 nadir >34
  • PETCO2 may be <36 at rest and at anaerobic threshold
  • VD/VT may not decrease with exercise
 Close to baseline Often highly increased max RR (>55/min); high RR early (with low workload)
Abnormal breathing pattern (hyperventilation) Normal Variable
  • VT increase may be suboptimal
 No significant change with exercise
  • O2Sat >96% at rest, decreases <3% w/exercise
  • Peak A-a O2 difference <35
 Reduced ventilatory efficiency
  • Ventilatory reserve <30%
  • VE-VCO2 slope >32
  • VE/VCO2 nadir >34
  • PETCO2 often <36 at rest
  • PETCO2 <36 at anaerobic threshold
  • VD/VT may not decrease with exercise
 Normal Often highly increased max RR (>55/min); high RR early (with low workload)
PFTs: pulmonary function tests; VT: tidal volume; O2Sat: oxygen saturation (measured by pulse oximetry); IC: inspiratory capacity; VE: minute ventilation (L/min); VCO2: measurement of carbon dioxide output from the lungs (L/minute); PETCO2: end-tidal carbon dioxide tension (mmHg); VD/VT: proportion of dead space ventilation (VD) per tidal volume breath; RR: respiratory rate; FEV1: forced expiratory volume in one second; FVC: forced vital capacity; TLC: total lung capacity; EIB: exercise-induced bronchoconstriction; A-a O2 difference: difference between alveolar and arterial oxygen partial pressures (mmHg).
Graphic 141716 Version 1.0

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