Key result
Inspiration reduced left ventricular stroke volume by 7% in normal patients (P<0.01) and by 25% in patients with airway obstruction (P<0.001).
Why the study?
Does inspiration affect left ventricular stroke volume in normal patients and those with airway obstruction or pericardial tamponade?
Observational (n=22)
Does inspiration affect left ventricular stroke volume in normal patients and those with airway obstruction or pericardial tamponade?
p-value: p=<0.01
Inspiration causes an immediate fall in left ventricular stroke volume, likely due to reduced left ventricular filling, with exaggerated effects in patients with airway obstruction.
May exaggerate inspiratory LV effects in obstruction; leaves open relevance to tamponade and need for prospective studies.
The pressure gradient technique was used to evaluate effects of respiration on left ventricular stroke volume in 22 patients: 11 normal patients; eight patients with airway obstruction; and three patients with pericardial tamponade. In normals, stroke volume, systolic pressure, and pulse pressure fell an average of 7, 3 and 11% ( P < 0.01), respectively, during inspiration. In patients with airway obstruction, these parameters decreased by 25, 12 and 23% ( P < 0.001), respectively. After breath-holding, stroke volume also fell immediately with the onset of inspiration in both groups. These results are consistent with a reduction in left ventricular filling during inspiration as the factor primarily responsible for the fall in stroke volume. In patients with pericardial tamponade, variations in left ventricular stroke volume, systolic pressure and pulse pressure were related to: (1) an immediate fall in stroke volume with the onset of inspiration; and (2) a subsequent increase in stroke volume presumably due to an inspiratory increase in right ventricular stroke volume.
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Ruskin et al. (1973) conducted an observational in Normal, airway obstruction, pericardial tamponade (n=22). Inspiration was evaluated on Change in left ventricular stroke volume, systolic pressure, and pulse pressure (p=<0.01). Inspiration reduced left ventricular stroke volume by 7% in normal patients (P<0.01) and by 25% in patients with airway obstruction (P<0.001).
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