Chest wall kinematics and Hoover's sign.
ABSTRACT No attempt has been made to quantify the observed rib cage distortion (Hoover's sign) in terms of volume displacement. We hypothesized that Hoover's sign and hyperinflation are independent quantities.
Twenty obstructed stable patients were divided into two groups according to whether or not they exhibited Hoover's sign during clinical examination while breathing quietly. We evaluated the volumes of chest wall and its compartments: the upper rib cage, the lower rib cage and the abdomen, using optoelectronic plethysmography.
The volumes of upper rib cage, lower rib cage and abdomen as a percentage of absolute volume of the chest wall were similar in patients with and without Hoover's sign. In contrast, the tidal volume of the chest wall, upper rib cage, lower rib cage, their ratio and abdomen quantified Hoover's sign, but did not correlate with level of hyperinflation.
Rib cage distortion and hyperinflation appear to define independently the functional condition of these patients.
- SourceAvailable from: ncbi.nlm.nih.govJournal of Clinical Investigation 10/1958; 37(9):1279-85. · 12.81 Impact Factor
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ABSTRACT: We have used three-dimensional reconstructions obtained with spiral computed tomography to measure total diaphragm length (Ldl) and surface area (Adl), the length (Ldo) and surface area (Ado) of the dome, and the length (Lap) and surface area (Aap) of the zone of apposition in 10 hyperinflated patients with severe chronic obstructive pulmonary disease, or COPD (FEV1 = 27% predicted: FRC = 225% predicted) and 10 normal subjects matched for age, sex, and height. Measures of Ldl, Adl, Lap, and Aap decreased linearly between FRC and TLC in the two groups, but Ldo and Ado did not change. On average, patients' Adl and Aap at FRC were reduced to 73% and 54% of normal values, whereas Ado was unaffected. When compared at similar absolute lung volumes, mean diaphragm dimensions were similar in patients with COPD and normal subjects, but individual values were very variable in both groups. This variability was partly accounted for by differences in body weight: i.e., the greater the weight, the longer the diaphragm. We conclude that (1) patients with COPD have marked reductions in Adl and Aap at FRC but have diaphragm dimensions similar to those of normal subjects when compared at similar absolute lung volumes, and (2) normal subjects and patients with COPD show substantial intersubject variability in diaphragm dimensions that is partly explained by differences in body weight.American Journal of Respiratory and Critical Care Medicine 09/1997; 156(2 Pt 1):504-8. · 11.04 Impact Factor
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ABSTRACT: 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. Participants and measurements: 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. 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). 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.Chest 02/2004; 125(2):459-65. · 5.85 Impact Factor