Normal asynchrony of left ventricular long and short axes: their relationship with aortic hemodynamics.

Background: The relationship between left ventricular (LV) long and short axes, aortic pressure (P), flow velocity (U) and wave intensity is not well established.

Methods: Eleven dogs were anaesthetized and mechanically ventilated and LV long and minor axes shortening velocities were calculated using ultrasound crystals. P and U were measured in the ascending aorta using a high fidelity pressure catheter and ultrasonic flow transducer.

Problems in the measurement of functional residual capacity.

Accurate assessment of lung volume in infancy is important to determine the impact of disease and the efficacy of therapies. A new generation of infant plethysmographs with lower apparatus deadspace has been produced, but gives lower volume results than those from older traditional plethysmographs. We hypothesized that the new plethysmographs might have greater sensitivity to the adiabatic effect and hence they, rather than the traditional plethysmographs, produced erroneous results.