We hypothesize that the stroke volume variation measured using the commercially available LiDCO monitor provides a reasonable estimate of volume when compared to standard measures. This study will collate data that is already being collected by the bedside nurses.

Objective: To compare measurement of stroke volume variance with intake/output measurements, weight, BUN/Creatnine values, and central venous pressure.

Design: Non-experimental, non-randomized observational comparative study.

Setting: The sixteen bed Neurocritical Care Unit at Duke University Hospital.

Patients: 45 adult (over 18 years) subjects with intracranial pathology who require volume resuscitation. Only patients with current LiDCO monitoring will be considered eligible for inclusion in the study.

Interventions: This is an observational study. Subjects will receive standard-of-care treatment without additional intervention.

Data Analysis: All data will be collected by the principal investigator / study coordinator. Personal patient information will be removed (deidentified) from the permanent data collection records to protect patient confidentiality. Data collected will be entered into a Microsoft Excel electronic spreadsheet and will be saved on a USB Disk drive to be stored in a locked cabinet in the investigator's office. Statistical analysis using SAS v9.1, (Cary, NC) will be conducted with a level of significance set at .05 (alpha) using standardized comparative analysis techniques.

Inclusion Criteria:

• Admitted to the neurocritical care unit have an arterial line in place already connected to LiDCO monitor Physician order for monitoring intake and output

Exclusion Criteria:

• pregnant females

Neurologically injured patients