Impact of Increasing Lower Body Negative Pressure and Its Abrupt Release on Left Ventricular Hemodynamics in Anesthetized Pigs

Birgit Zirngast; Leonhard Berboth; Martin Manninger; Helmut Hinghofer-Szalkay; Daniel Scherr; Lonnie G Petersen; Nandu Goswami; Alessio Alogna; Heinrich Maechler

doi:10.3390/jcm11195858

Impact of Increasing Lower Body Negative Pressure and Its Abrupt Release on Left Ventricular Hemodynamics in Anesthetized Pigs

J Clin Med. 2022 Oct 3;11(19):5858. doi: 10.3390/jcm11195858.

Authors

Birgit Zirngast¹, Leonhard Berboth², Martin Manninger³, Helmut Hinghofer-Szalkay⁴, Daniel Scherr³, Lonnie G Petersen⁵, Nandu Goswami^{4

6}, Alessio Alogna², Heinrich Maechler¹

Affiliations

¹ Department of Cardiac Surgery, Medical University Graz, 8036 Graz, Austria.
² Department of Cardiology, Charité-Campus Virchow-Klinikum, 13353 Berlin, Germany.
³ Department of Internal Medicine, Division of Cardiology, Medical University Graz, 8036 Graz, Austria.
⁴ Department of Physiology, Otto Loewi Center, Medical University Graz, 8036 Graz, Austria.
⁵ Institute of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA.
⁶ Physiology Division, Mohammed Bin Rashi University of Medicine and Health Sciences, Dubai 505055, United Arab Emirates.

Abstract

Lower body negative pressure (LBNP) has been implemented as a tool to simulate systemic effects of hypovolemia, understand orthostatic challenges and study G load stress in humans. However, the exact hemodynamic mechanisms of graded LBNP followed by its abrupt release have not been characterized in detail, limiting its potential applications in humans. Here, we set out to investigate the immediate hemodynamic alterations occurring during LBNP in healthy Landrace pigs. Invasive cardiac monitoring via extensive pressure volume loop analysis was carried out during application of incremental LBNP up to life threatening levels from -15 to -45 mmHg as well as during its abrupt release. Three different sealing positions were evaluated. Incremental LBNP consistently induced a preload dependent depression of systemic hemodynamics according to the Frank-Starling mechanism. Overall, the pressure-volume loop progressively shifted leftwards and downwards with increasing LBNP intensity. The abrupt release of LBNP reverted the above-described hemodynamic changes to baseline values within only three respiratory cycles. These data provide quantitative translational insights into hemodynamic mechanisms of incremental and very high levels of LBNP, levels of seal and effect of abrupt release for future human applications, such as countermeasure development for long spaceflight.

Keywords: Landrace pigs; invasive hemodynamics; lower body negative pressure; preload reduction; pressure-volume loops.

Grants and funding

This research received no external funding. Alogna is supported by the Clinician Scientist Program of the Berlin Institute of Health (BIH) and by the Deutsche Forschungsgemeinschaft (DFG; CRC 1470, Z01).