Background <p>Electrical cardiometry (EC) is a noninvasive method that continuously measures thoracic fluid content (TFC), providing real-time assessment of fluid status. This study evaluated the prognostic value of EC-derived TFC in predicting outcomes among critically ill respiratory patients.</p> Methods <p>A prospective observational study was conducted on 130 adult patients admitted to the RICU of Mansoura University Hospitals. Daily hemodynamic measurements were obtained using the ICON™ noninvasive cardiometer. Primary outcomes included duration of invasive mechanical ventilation (MV) and RICU stay, while in-hospital mortality was the secondary endpoint. Correlations between TFC and clinical, hemodynamic, and biochemical parameters were analyzed.</p> Results <p>Pneumonia was the most frequent diagnosis (65.4%), followed by COPD (15.4%). Non-survivors had significantly higher mean TFC values across all follow-up days compared with survivors (<i>p</i> &lt; 0.001). TFC correlated positively with RICU stay and serum lactate levels and negatively with mean arterial pressure. At a cutoff value of 43 kΩ⁻¹, TFC predicted mortality with an AUC of 0.656, sensitivity of 85.7%, and specificity of 67.3%. Elevated TFC values were also significantly associated with the need for mechanical ventilation and vasopressor use (<i>p</i> &lt; 0.001). At a cutoff value of 43 kΩ⁻¹, TFC predicted in-hospital mortality with a sensitivity of 85.7%, specificity of 67.3%, and an area under the curve (AUC) of 0.656.</p> Conclusion <p>Electrical cardiometry provides a reliable, noninvasive technique for continuous hemodynamic monitoring in respiratory critical care. Elevated TFC values were independently associated with higher mortality, prolonged mechanical ventilation, and extended RICU stay.</p> Trial registration <p>ClinicalTrials.gov identifier NCT07100821.</p>