Micro-lightguide spectrophotometry assessment of hepatic and intestinal microcirculation in endotoxemic rats during intravenous treatment with angiotensin II.

INTRODUCTION: During septic shock, impairment of microcirculation leads to enhanced permeability of intestinal mucosa triggered by generalized vasodilation and capillary leak. Intravenous angiotensin II (AT-II) has been approved for the treatment of septic shock; however, no in-vivo data exist on the influence of AT-II on hepatic and intestinal microcirculation. MATERIAL AND METHODS: Sixty male Lewis rats were randomly assigned to six study groups (each n = 10): sham, lipopolysaccharide-induced septic shock, therapy with low- or high-dose AT-II (50 or 100 ng/kg/min, respectively), and septic shock treated with low- or high-dose AT-II. After median laparotomy, hepatic and intestinal microcirculation measures derived from micro-lightguide spectrophotometry were assessed for 3 h and included oxygen saturation (SO2), relative blood flow (relBF) and relative hemoglobin level (relHb). Hemodynamic measurements were performed using a left ventricular conductance catheter, and blood samples were taken hourly to analyze blood gasses and systemic cytokines. RESULTS: AT-II increased mean arterial pressure in a dose-dependent manner in both septic and non-septic animals (p < 0.001). Lower hepatic and intestinal SO2 (both p < 0.001) were measured in animals without endotoxemia who received high-dose AT-II treatment, however, significantly impaired cardiac output was also reported in this group (p < 0.001). In endotoxemic rats, hepatic relBF and relHb were comparable among the treatment groups; however, hepatic SO2 was reduced during low- and high-dose AT-II treatment (p < 0.001). In contrast, intestinal SO2 remained unchanged despite treatment with AT-II. Intestinal relBF (p = 0.028) and interleukin (IL)-10 plasma levels (p < 0.001) were significantly elevated during treatment with high-dose AT-II compared with low-dose AT-II. CONCLUSIONS: A dose-dependent decrease of hepatic and intestinal microcirculation during therapy with AT-II in non-septic rats was observed, which might have been influenced by a corresponding reduction in cardiac output due to elevated afterload. While hepatic microcirculation was reduced during endotoxemia, no evidence for a reduction in intestinal microcirculation facilitated by AT-II was found. In contrast, both intestinal relBF and anti-inflammatory IL-10 levels were increased during high-dose AT-II treatment.

Hypotension Prediction Index based protocolized haemodynamic management reduces the incidence and duration of intraoperative hypotension in primary total hip arthroplasty: a single centre feasibility randomised blinded prospective interventional trial.

The "Hypotension Prediction Index (HPI)" represents a newly introduced monitoring-tool that aims to predict episodes of intraoperative hypotension (IOH) before their occurrence. In order to evaluate the feasibility of protocolized care according to HPI monitoring, we hypothesized that HPI predicts the incidence of IOH and reduces the incidence and duration of IOH. This single centre feasibility randomised blinded prospective interventional trial included at total of 99 patients. One group was managed by goal-directed therapy algorithm based on HPI (HPI, n = 25), which was compared to a routine anaesthetic care cohort (CTRL, n = 24) and a third historic control group (hCTRL, n = 50). Primary endpoints included frequency (n)/h, absolute and relative duration (t (min)/% of total anaesthesia time) of IOH. Significant reduction of intraoperative hypotension was recorded in the HPI group compared to the control groups (HPI 48%, CTRL 87.5%, hCTRL 80%; HPI vs. CTRL, respectively hCTRL p < 0.001). Perioperative quantity of IOH was significantly reduced in the interventional group compared to both other study groups (HPI: 0 (0-1), CTRL: 5 (2-6), hCTRL: 2 (1-3); p < 0.001). Same observations were identified for absolute (HPI: 0 (0-140) s, CTRL: 640 (195-1315) s, hCTRL 660 (180-1440) s; p < 0.001) and relative duration of hypotensive episodes (minutes MAP ≤ 65 mmHg in  % of total anaesthesia time; HPI: 0 (0-1), CTRL: 6 (2-12), hCTRL 7 (2-17); p < 0.001). The HPI algorithm combined with a protocolized treatment was able to reduce the incidence and duration of hypotensive events in patients undergoing primary hip arthroplasty.Trial registration: NCT03663270.