Estimated plasma volume status and the risk of 30-day mortality among patients with traumatic brain injury: analysis from the MIMIC-IV database.

BACKGROUND

Plasma volume status (PVS) is an indicator of fluid status, and fluid balance is linked to the prognosis of critically ill patients. This analysis aimed to examine the association of estimated PVS (ePVS) with mortality risk among traumatic brain injury (TBI) patients.

METHODS

This retrospective cohort analysis extracted TBI patient data from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database spanning 2008-2022. ePVS was calculated using the Duarte formula (Duarte-ePVS) and the Kaplan-Hakim formula (KH-ePVS), respectively. The associations of Duarte-ePVS and KH-ePVS with 30-day mortality risk among TBI patients were examined via Cox regression analyses. The non-linear associations of ePVS with 30-day mortality were analyzed via the restricted cubic splines (RCS) curve.

RESULTS

The analysis cohort comprised 1,440 TBI patients, survival outcomes showed 247 (17.15%) deaths and 1,193 (82.85%) survivors at 30-day follow-up. A 1-SD (standard deviation) increase in KH-ePVS levels [HR (95%CI) = 1.17 (1.02-1.34)] and KH-ePVS levels ≥11.458 [HR = 1.43 (1.06-1.95)] were linked to an elevated risk of 30-day mortality. No significant relationships of high Duarte-ePVS levels and Duarte-ePVS levels ≥7.134 with 30-day mortality risk were found (P > 0.05). No significant nonlinear association between KH-ePVS levels and 30-day mortality risk was found (P > 0.05).

CONCLUSION

Elevated KH-ePVS levels were associated with an increased risk of short-term mortality among TBI patients, indicating a potential role for KH-ePVS levels in risk assessment.