During the course of their acute illness patients with subarachnoid hemorrhage and severe traumatic brain injury often develop disturbances in their fluid balance and electrolyte homeostasis. These shifts are associated with worse outcome and increased morbidity.

The aim of this observational study is to systematically analyze the incidence, characteristics, potential diagnostic markers and predisposing factors of such disturbances. The investigators hypothesize that many disturbances cannot be classified with a standard diagnostic approach and that variable fluid management contributes to their pathophysiology.

Patients will be closely monitored clinically and the exact fluid and electrolyte balances will be recorded. Treatment decisions are within the bedside physicians responsibility. Baseline fluid management is standardised. No interventions are planned. The observation period equal the duration of ICU stay.

Background

Electrolyte disturbances and fluid shifts are common in patients with subarachnoid hemorrhage (SAH) or traumatic brain injury (TBI). They usually have a rapid onset with impact on morbidity (possibly mortality) and length of stay. So far the understanding of underlying pathophysiologies and the contribution of iatrogenic influences is not fully understood.

Only limited evidence and data on classification, management and outcome of patients exists.

Objective

To describe the incidence, characteristics and duration of sodium and fluid disturbances in patients with SAH or TBI.

To document exact fluid and electrolyte management To evaluate predisposing factors and potential predicting biomarkers such as natriuretic peptides, renin-aldosterone system.

Methods

Prospective systematic observational study with 50 patients in the SAH group and 50 patients in the TBI group.

8hourly clinical assessment, blood and urin samples. Defined trigger points for additional measurements.

Continuous fluid balance documentation Daily measurement of natriuretic peptides, aldosterone and renin

Inclusion Criteria:

• non-traumatic subarachnoid hemorrhage
• severe traumatic brain injury (GCS<9)

Exclusion Criteria

• younger than 18 years
• time to admission after injury or bleed more than 7days
• death expected in less than 12hours

Intenisve Care Medicine patients with non-traumatic subarachnoid hemorrhage or severe traumatic brain injury