Effect of norepinephrine on the vascular waterfall and tissue perfusion in vasoplegic hypotensive patients: a prospective, observational, applied physiology study in cardiac surgery

Abstract

Background Norepinephrine is a commonly used drug for treating vasoplegic acute circulatory failure in ICU. The prediction of norepinephrine macro- and micro-circulatory response is complicated by its uneven receptors’ distribution between the arterial and the venous structures, and by the presence of a physiological vascular waterfall (VW) that disconnects the arterial and the venous circulation in two pressure systems. The objectives of this study were to describe the VW in patients with arterial hypotension due to vasodilatory circulatory shock, and its behavior according to its response to norepinephrine infusion. Methods A prospective, observational, bi-centric study has included adult patients, for whom the physician decided to initiate norepinephrine during the six first hours following admission to the ICU after cardiac surgery, and unresponsive to a fluid challenge. The mean systemic pressure (MSP) and the critical closing pressure (CCP) were measured at inclusion and after norepinephrine infusion. Results Thirty patients were included. Norepinephrine increased arterial pressure and total peripheral resistances in all cohort. The cohort was dichotomized as VW responders (patients with a change of VW over the least significant change (≥ 93% increase in VW)), and as VW non-responders. In 19 (63%) of the 30 patients, VW increased from 3.47 [− 14.43;7.71] mmHg to 43.6 [25.8;48.1] mmHg, p < 0.001) with norepinephrine infusion, being classified as VW responders. The VW responders improved cardiac index (from 1.8 (0.6) L min−1 m−2 to 2.2 (0.5) L min−1 m−2, p = 0.002), capillary refill time (from to 4.2 (1.1) s to 3.1 (1) s, p = 0.006), and pCO2 gap (from 9 [7;10] mmHg to 6 [4;8] mmHg, p = 0.04). No baseline parameters were able to predict the VW response to norepinephrine. In comparison, VW non-responders did not significantly change the VW (from 5 [-5;16] mmHg to -2 [-12;15] mmHg, p = 0.17), cardiac index (from 1.6 (0.3) L min−1 m−2 to 1.8 (0.4) L min−1 m−2, p = 0.09) and capillary refill time (from 4.1 (1) s to 3.7 (1.4), p = 0.44). Conclusions In post-cardiac surgery patients with vasoplegic arterial hypotension, the vascular waterfall is low. Norepinephrine did not systematically restore the vascular waterfall. Increase of the vascular waterfall was associated with an improvement of laboratory and clinical parameters of tissue perfusion.

Predictive value of dynamic arterial elastance for vasopressor withdrawal: a systematic review and meta-analysis

“…It is important to emphasize that Ea dyn is correlated with vascular waterfall (WV, a pressure essential for maintaining tissue perfusion during periods of low blood flow) and critical closing pressure (CCP, the arterial pressure at which blood flow is halted owing to arteriole occlusion) [ 27 ]. The augmentation of VW and CCP, facilitated by the administration of norepinephrine, contributes to an enhancement in tissue perfusion [ 28 ]. In alignment with the aforementioned findings, the Ea dyn can serve as a variable that elucidates the intricate relationship between cardiac function and arterial load, delineates the effects of hemodynamic treatment on arterial load, and reveals hemodynamic coherence.…”

Severe Refractory Vasoplegic Shock Syndrome after OPCABG Successfully Treated with Hydroxycobalamin: A Case Report and Review of the Literature

“…Nevertheless, in some patients, the blood pressure constantly rises, whereas cardiac output might not increase. Therefore, restoring blood pressure with norepinephrine infusion may not always be associated with an improvement in tissue perfusion [ 17 ]. In particular, the Vasoplegic Shock after Cardiac Surgery (VANCS) trial evaluated the role of norepinephrine specifically in vasoplegia treatment versus vasopressin as a first-line therapy in patients recovering from cardiac surgery [ 18 ].…”

Significance of critical closing pressures (starling resistors) in arterial circulation

“…In adequately fluid-resuscitated patients, evidence of tissue hypoperfusion, such as prolonged refill capillary time and oliguria with intra-abdominal hypertension, can be managed by titrating norepinephrine to higher MAP levels. Beneficial or detrimental effects of vasopressors on tissue perfusion can occur depending on their relative actions on MAP and Pcc.Monitoring TPP may offer an advantage for blood pressure optimization in circulatory shock patients [ 9 ]. In a retrospective study, lower TPP was associated with higher mortality, longer hospital stay, and higher blood lactate levels than patients with higher TPP for the same MAP [ 10 .…”