This study aimed to investigate the effect of the central venous-to-arterial carbon dioxide partial pressure difference (Pcv-aCO2) on the administration of cardiotonic drugs in patients with early-stage septic shock. A retrospective study was conducted on 120 patients suffering from septic shock. At admission, the left ventricular ejection fraction (LVEF) and Pcv-aCO2 of the patients were obtained. On the premise of mean arterial pressure (MAP) ≥ 65 mmHg, the patients were divided into two groups according to the treatment approaches adopted by different doctors-Control group: LVEF ≤50%; Observation group: Pcv-aCO2 ≥ 6. Both groups received cardiotonic therapy. The two groups of patients had similar general conditions and pre-resuscitation conditions (P > 0.05). Compared to the Control group, the Observation group had a higher MAP, Lac clearance rate, and urine output after six hours of resuscitation (P < 0.05), but a lower absolute value of Lac, total fluid intake in 24 hours, and a lower number of patients receiving renal replacement therapy during hospitalization (P < 0.05). After six hours of resuscitation, the percentages of patients meeting central venous oxygen saturation and central venous pressure targets were not significantly different between the Control and Observation groups (P > 0.05). There was no difference in the 28-day mortality rate between the two groups (P > 0.05). Pcv-aCO2 is more effective than LVEF in guiding the administration of cardiotonic drugs in the treatment of patients with septic shock.