Augmented Renal Clearance in Patients with Subarachnoid Hemorrhage

Background: Patients with subarachnoid hemorrhage (SAH) typically exhibit hyperdynamic cardiovascular hemodynamics, which may lead to increased medication clearance. The aims of this study were to evaluate the actual creatinine clearance (CrCl_A) in an aneurysmal SAH population and the effect of the development of cerebral vasospasm (CV) along with its treatment to better understand if this population exhibits augmented renal clearance (ARC). Methods: This was a prospective, single-center study in a neurosciences ICU at a university hospital. A total of 20 patients were consented and provided a 24-h urine sample to measure the CrCl_A. If patients experienced CV, a 24-h urine collection was repeated during vasospasm treatment. CrCl_A was measured using a modified Jaffe assay. Results: Among the 20 patients enrolled, the mean SAH CrCl_A was 325.93 ± 135.20 ml/min 1.73 m² and this differed significantly from the SAH estimated creatinine clearance (CrCl_E) 144.93 ± 42.82 ml/min 1.73 m² (p < 0.001). Four patients developed CV; the mean CV CrCl_A was 558.43 ± 356.12 ml/min 1.73 m² and there was no significant difference when compared to those patients’ mean SAH CrCl_A (246.91 ± 84.14 ml/min 1.73 m², p = 0.16). Conclusions: ARC was present in 100 % of the patients with recent SAH enrolled. Although ARC remained present in the patients who experienced CV, their creatinine clearance was not significantly further augmented. Further work is needed to clarify the impact of such clearances on renally excreted medications and how the development and treatment of CV further augment these findings.