Suction against resistance: a new breathing technique to significantly improve the blood flow ratio of the superior and inferior vena cava

Abstract

Suction provokes reduction in blood flow in the inferior vena cava. Ratio between the inferior and superior vena cava blood flow diminished during suction. Manometer used during breathing standardises MR phase-contrast blood flow measurements.

Suction/Inspiration against resistance or standardized Mueller maneuver : a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study

“…Despite occasional controversial discussions, there was a general consensus that expiration followed by breathhold leads to an improved contrast in pulmonary arteries in comparison to inspiration followed by breathhold [8][9][10][11][12][13]18]. To our knowledge, the present prospective clinical study is the first to investigate on a patient level how the recently introduced and promising Bsuction against resistance^breathing maneuver might influence contrast behavior compared to other breathing techniques used in clinical routine [14]. Indeed, in comparison to previous CT studies including a larger cohort and comparing inspiration versus expiration breathing maneuvers, our absolute CT attenuation levels exceed these previously reported results.…”

“…As described graphically in Fig. 6 (and Video 1, supplementary material), suction against resistance exerts a specific physiological influence on the flow ratios of the superior und inferior vena cava, as described recently [14,19]. First, during normal inspiration without any resistance, the diaphragm moves caudally.…”

“…This technique has been recently described in more detail [14]. It should be emphasized that despite suspicious PE, advanced age or general diseases, all patients were able to comply with the requested breathing maneuver.…”

“…A recently published magnetic resonance (MR) study with volunteers demonstrated for the first time that a Mueller-like maneuver (suction or inspiration against resistance) could significantly elevate blood flow through the SVC while reducing blood flow through the IVC [14]. Nevertheless, it is not known if this observation has any relevant clinical influence or if truly guarantees better contrast within the PA of patients during contrast-enhanced CT.…”

“…2 This image illustrates patient position inside the CT scanner during suction against resistance using the dedicated breathing device. The technique is described more in detail in recent publication [14]. Observing the manometer, the patient gets clear feedback and thus can control airway pressure a region of interest placed in the center of the pulmonary trunk was used with a triggering threshold of 80 HU and a delay of 5 sec after reaching this cutoff value.…”