Glomerular hyperfiltration in patients with severe trauma

Augmented renal clearance or glomerular hyperfiltration (GHF) can significantly affect the clinical outcomes of renally eliminated drugs by promoting subtherapeutic drug exposure. The aggression suffered in patients who suffer severe trauma is a predisposition to manifest GHF and the identification of these patients remains a clinical challenge. The main objective of this study was to describe the prevalence of GHF in a cohort of critically ill trauma patients.

Prospective observational study of a cohort of adult patients admitted after suffering severe trauma or polytrauma in the Anesthesiology ICU of the University Hospital of Albacete (Spain). Creatinine clearance (ClCr) was calculated in a 4-h urine collection sample at 24, 72 and 168 h after admission applying the formula; CrCl: [Diuresis in ml (urine/4 h) × Creatinine in urine (mg/dl)] ÷ [240 (minutes) × Creatinine in plasma (mg/dl)]. A CrCl above 130 mL/min was considered GHF. The analyses were performed with the statistical software R version 4.0.4.

85 patients were included. The median age of the patients was 51 years (IQR 26), 78.82% male. 68 patients were male (78.82%). 75.29% of the patients were polytraumatized. 61 patients (71.76%) presented GHF at some point in the CrCl determination. At 24 h of admission, 56.34% of the patients presented GHF with a mean CrCl of 195.8 ml/min, 61.11% of the patients presented it at 72 h with a mean CrCl of /min and 56.52% presented GHF at 168 h of admission with a mean CrCl of 207 ml/min. A significant positive relationship (p = 0.07) was found between GHF manifested at 72 h and at 168 h. We observed a statistically significant relationship between this phenomenon with younger ages, lower ISS scores and lower plasma creatinines.

GHF are a common condition in critically ill patients admitted for severe trauma. We recommend the use of CrCl to assess renal function and make dosage adjustments. Studies are required to understand the clinical impact of these phenomena on drug elimination and to be able to establish the ideal dosage in those cases.