Fig. 3. Impacts of dobutamine (DOB) and norepinephrine (NE) on LV function and hemodynamics in acute T2 SCI.

Dependent variables from 30 mins (i.e. start of hemodynamic management) to 4 h post-SCI were analyzed using a two-way repeated-measures ANOVA (factors: time, group), and post hoc comparisons were made with Tukey’s test (between-group) and Fisher’s LSD (within-group compared to 30 mins post-SCI). a Following experiment 1 (control [CON], closed circles; n = 8), an additional n = 14 animals received hemodynamic management starting 30 mins post-SCI with either DOB (squares, n = 7) titrated to a target E_es of ~2.5–2.9 mmHg ml⁻¹, or NE (triangles; n = 7) titrated to a mean arterial pressure (MAP) of 85–90 mmHg. Three animals receiving DOB had a relatively high baseline E_es, and as a result received minimal doses of DOB (i.e., ≤0.5 μg kg⁻¹ min⁻¹, DOB-, open squares; n = 3) while n = 4 animals received substantial DOB doses (i.e., ≥2.5 μg kg⁻¹ min⁻¹, DOB+, closed squares). b Data points are means and error bars represent s.d. Both DOB+ and NE augmented MAP, however MAP was significantly elevated  in DOB+ compared to CON animals. c LV contractility, E_es, was augmented by both DOB and NE. d Only DOB+ generated increases in LV stroke volume (SV) and e cardiac output (Q), which were not observed with NE. f There were no significant changes to heart rate (HR) with hemodynamic management, nor were there differences between the groups. g LV afterload increased with NE management but not with DOB. h Stroke work, an index of systolic function, is only increased with DOB+, i despite increases to P_max in both NE and DOB. *p < 0.05, **p < 0.01, ***p < 0.001 (within-group effect for time). ^ap < 0.05 vs CON; ^bp < 0.05 vs DOB-; ^cp < 0.05 vs NE. Within-group comparisons between 30 mins and 1 h to 3 h post-SCI are available in Supplementary Tables 3–5. Source data are provided as a Source Data file.