Guiding Fluid Resuscitation in Septic Shock: Ultrasound vs. Noninvasive Cardiac Output Monitoring

This study is a prospective randomized controlled trial conducted in the Emergency Department of Guangzhou Panyu Central Hospital. Eligible adult patients with septic shock, admitted between july 2023 and july 2025, were enrolled after informed consent. Demographic and baseline clinical data, including age, gender, comorbidities, mean arterial pressure, baseline lactate, and vital signs, were collected at enrollment.

A total of 60 patients were randomly assigned to one of two intervention groups using block randomization generated by SPSS software, with allocation concealed by sealed envelopes.

• Critical Care Ultrasound Group: Patients underwent bedside ultrasound assessment, including inferior vena cava diameter and collapsibility index (IVC-CI), left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), ventricular wall motion, and pulmonary B-lines, to guide individualized fluid resuscitation. Ultrasound evaluations were repeated every 1-2 hours until resuscitation targets were achieved.
• Non-Invasive Cardiac Output Monitoring (NICOM) Group: Patients received continuous hemodynamic monitoring using thoracic bioreactance technology. Parameters including cardiac output (CO), stroke volume (SV), stroke volume variation (SVV), and systemic vascular resistance (SVR) were continuously recorded and used to guide fluid therapy adjustments until resuscitation targets were achieved.

In both groups, all patients received standard septic shock management based on the 2021 Surviving Sepsis Campaign guidelines, including early antibiotics, vasopressor therapy, and organ support. Outcomes recorded included total fluid volume within the first 6 hours, time to resuscitation targets, complications (e.g., pulmonary edema, renal injury, ARDS), emergency department and hospital length of stay, 28-day mortality, and adverse events (e.g., arrhythmias, anaphylaxis).

Inclusion criteria

• diagnosis of septic shock in accordance with the Surviving Sepsis Campaign International ;
• receipt of initial fluid resuscitation in the emergency department with a hospital stay of at least 6 hours;
• age ≥ 18 years;
• provision of informed consent.

Excluded criteria:

• contraindications to rapid fluid administration (e.g., end-stage renal disease, end-stage heart failure, acute pulmonary edema);
• inability to comply with treatment, such as patients with severe trauma, burns, cancer undergoing chemotherapy, pregnant or lactating women, and those with mental illness;
• withdrawal from treatment or transfer to another facility within 24 hours of admission.