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Introduction: High-dose catecholamines can impair hypoxic pulmonary vasoconstriction and increase shunt fraction. We aimed to determine if Angiotensin II (Ang-2) is associated with improved PaO 2 /FiO 2 and SpO 2 /FiO 2 in patients in shock., Methods: Adult patients at four tertiary care centers and one community hospital in the United States who received Ang-2 from July 2018-September 2020 were included in this retrospective, observational cohort study. PaO 2 , SpO 2 , and FiO 2 were measured at 13 timepoints during the 48-h before and after Ang-2 initiation. Piecewise linear mixed models of PaO 2 /FiO 2 and SpO 2 /FiO 2 were created to evaluate hourly changes in oxygenation after Ang-2 initiation. The difference in the proportion of patients with PaO 2 /FiO 2  ≤ 300 mm Hg at the time of Ang-2 initiation and 48 h after was also examined., Results: The study included 254 patients. In the 48 h prior to Ang-2 initiation, oxygenation was significantly declining (hourly PaO 2 /FiO 2 change -4.7 mm Hg/hr, 95% CI - 6.0 to -3.5, p  < .001; hourly SpO 2 /FiO 2 change -3.1/hr, 95% CI-3.7 to -2.4, p  < .001). Ang-2 treatment was associated with significant improvements in PaO 2 /FiO 2 and SpO 2 /FiO 2 in the 48-h after initiation (hourly PaO 2 /FiO 2 change +1.5 mm Hg/hr, 95% CI 0.5-2.5, p   =  .003; hourly SpO 2 /FiO 2 change +0.9/hr, 95% CI 0.5-1.2, p  < .001). The difference in the hourly change in oxygenation before and after Ang-2 initiation was also significant ( p interaction  < 0.001 for both PaO 2 /FiO 2 and SpO 2 /FiO 2 ). This improvement was associated with significantly fewer patients having a PaO 2 /FiO 2  ≤ 300 mm Hg at 48 h compared to baseline (mean difference -14.9%, 95% CI -25.3% to -4.6%, p   =  .011). Subgroup analysis found that patients with either a baseline PaO 2 /FiO 2  ≤ 300 mm Hg or a norepinephrine-equivalent dose requirement >0.2 µg/kg/min had the greatest associations with oxygenation improvement., Conclusions: Ang-2 is associated with improved PaO 2 /FiO 2 and SpO 2 /FiO 2 . The mechanisms for this improvement are not entirely clear but may be due to catecholamine-sparing effect or may also be related to improved ventilation-perfusion matching, intrapulmonary shunt, or oxygen delivery.

Introduction: Angiotensin II (Ang-2) is a non-catecholamine vasopressor that targets the renin-angiotensin-aldosterone system by agonism of the angiotensin type 1 receptor. Its utility as a vasopressor and a catecholamine-sparing agent was demonstrated in the pivotal ATHOS-3 trial, and numerous post-hoc analyses have shown reduced mortality in certain subsets of the population., Methods: Consecutive adult patients at 5 centers who received Ang-2 from 2017-2020 were included in this multicenter, retrospective observational cohort study. Patient demographics, hemodynamics, and adverse events were collected. The primary outcomes of the study were the mean difference in MAP and norepinephrine (NEpi)-equivalent dose at hours 0 and 3 following initiation of Ang-2 therapy., Results: One hundred and sixty-two patients were included in this study. The primary outcomes of an increase in MAP (mean difference 9.3 mmHg, 95% CI 6.4-12.1, p < 0.001) and a reduction in NEpi equivalent dose (mean difference 0.16 µg/kg/min, 95% CI 0.10-0.22, p < 0.001) between hours 0 and 3 were statistically significant. The median time to reach a MAP ≥65 was 16 minutes (IQR 5-60 min). After stratifying patients by the NED dose and number of vasopressors administered prior to the initiation of Ang-2, those with a NED dose < 0.2 µg/kg/min, NED dose < 0.3 µg/kg/min, or those on ≤ 3 vasopressors had a significantly greater reduction in NED by hour 3 than those patients above these thresholds., Conclusion: Ang-2 is an effective vasopressor and reduces catecholamine dose significantly. Its effect is rapid, with target MAP obtained within 30 minutes in most patients. Given the critical importance of adequate blood pressure to organ perfusion, Ang-2 should be considered when target MAP cannot be achieved with conventional vasopressors. Ang-2 should be utilized early in the course of shock, before the NED dose exceeds 0.2-0.3 µg/kg/min and before the initiation of the fourth-line vasopressor.