Background: The Frank-Starling curve is the basis of hemodynamics. Changes in cardiac output (CO) caused by central venous pressure (CVP) are the most important concerns in the treatment of critically ill patients.Objectives: To explore the use of CVP and its relevant mechanisms with respect to CO in the clinic.Methods: A total of 134 patients with circulatory shock were retrospectively included and analyzed. Hemodynamic data were recorded and analyzed at PICCO initiation and 24 h after PICCO. Data regarding 28-day mortality and renal function were also collected.Results: The patients were divided into a CVP?+ CO? group (n = 23), a CVP?+ CO? group (n = 29), a CVP?+ CO? group (n = 44), and a CVP?+ CO? group (n = 38) based on values at PICCO initiation and 24 h after PICCO. Post- hoc tests showed that the CVP?+ CO? group had a higher 28-day survival than the other groups [log-rank (Mantel-Cox) = 8.758, 95%, CI, 20.112-23.499, P = 0.033]. In terms of hemodynamic characteristics, the CVP?+ CO? group had a lower cardiac function index (CFI) (4.1 ± 1.4/min) and higher extravascular lung water index (EVLWI) (11.0 ± 4.7 ml/kg) at PICCO initiation. This group used more cardiotonic drugs (77.3%, P < 0.001) and had a negative fluid balance (-780.4 ± 1720.6 ml/24 h, P = 0.018) 24 h after PICCO than the other three groups. Cardiotonic drug use and dehydration treatment were associated with increased CFI (from 4.1 ± 1.4 /min to 4.5 ± 1.3/min, P = 0.07) and reduced ELVWI (from 11.0 ± 4.7 ml/kg to 9.0 ± 3.5 ml/kg, P = 0.029). Renal function tests showed that SCr and BUN levels in the CVP?+ CO? group were significantly improved (SCr from 197.1 ± 128.9 mmol/L to 154.4 ± 90.8 mmol/L; BUN from 14.3 ?mol/L ± 7.3 to 11.6 ± 7.0 ?mol/L, P < 0.05).Conclusions: Lower CVP was associated with increased CO, which may improve the 28-day prognosis in patients with circulatory shock. Notably, higher CO derived from lower CVP may also contribute to renal function improvement.