Chest wall kinematics and breathlessness during pursed-lip breathing in patients with COPD.
BACKGROUND
Pursed-lip breathing (PLB) is a strategy often spontaneously employed by patients with COPD during distress situations. Whether and to what extent PLB affects operational lung volume is not known. Also, conflicting reports deal with PLB capability of decreasing breathlessness.


METHODS
Twenty-two patients with mild-to-severe COPD were studied. Volumes of chest wall (CW) compartments (rib cage [RC] and abdomen) were assessed using an optoelectronic plethysmograph. Dyspnea was assessed by a modified Borg scale.


RESULTS
Compared to spontaneous breathing, patients with PLB exhibited a significant reduction (mean +/- SD) in end-expiratory volume of the CW (VCW) [VCWee; - 0.33 +/- 0.24 L, p < 0.000004], and a significant increase in end-inspiratory VCW (VCWei; + 0.32 +/- 0.43 L, p < 0.003). The decrease in VCWee, mostly due to the decrease in end-expiratory volume of the abdomen (VAbee) [- 0.25 +/- 0.21 L, p < 0.00002], related to baseline FEV(1) (p < 0.02) and to the increase in expiratory time (TE) [r(2) = 0.49, p < 0.0003] and total time of the respiratory cycle (TTOT) [r(2) = 0.35, p < 0.004], but not to baseline functional residual capacity (FRC). Increase in tidal volume (VT) of the chest wall (+ 0.65 +/- 0.48 L, p < 0.000004) was shared between VT of the abdomen (0.31 +/- 0.23 L, p < 0.000004) and VT of the rib cage (+ 0.33 +/- 0.29 L, p < 0.00003). Borg score decreased with PLB (p < 0.04). In a stepwise multiple regression analysis, decrease in VCWee accounted for 27% of the variability in Borg score at 99% confidence level (p < 0.008).


CONCLUSIONS
Changes in VCWee related to baseline airway obstruction but not to hyperinflation (FRC). By lengthening of TE and TTOT, PLB decreases VCWee and reduces breathlessness.
Bianchi
Roberto
R
Fondazione Don C. Gnocchi IRCCS, Via Imprunetana 124, 50020 Pozzolatico, Florence, Italy.
Gigliotti
Francesco
F
Romagnoli
Isabella
I
Lanini
Barbara
B
Castellani
Carla
C
Grazzini
Michela
M
Scano
Giorgio
G
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D004417:Dyspnea / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010991:Plethysmography; D011336:Probability; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis*; D012119:Respiration; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D035441:Thoracic Wall / Q000502:physiology*; D014109:Total Lung Capacity / Q000502:physiology*