Diurnal blood pressure and urine production in acute spinal cord injury compared with controls

Study design: This is a prospective observational study. Objectives: The objective of this study was to determine time-dependent changes in diurnal blood pressure (BP) and urine production in acute spinal cord injury (SCI). Setting: This study was conducted in a specialist, state-based spinal cord service in Victoria, Australia. Methods: Consenting patients admitted consecutively with acute SCI were compared with patients confined to bed rest while awaiting surgery and with mobilising able-bodied controls. Participants underwent ambulatory BP monitoring (ABPM), measurement of diurnal urine production and rated orthostatic symptoms over 1 year. Participants with night:day systolic BP (SBP) 100% as reverse dippers. Results: Participants comprised tetraplegics ( n =47, 40.0±17.3 years), paraplegics ( n =35, 34.4±13.9 years), immobilised ( n =18, 30.9±11.3 years) and mobilising ( n =44, 33.1±13.5 years) controls. At baseline, 24-h BP was significantly lower in tetraplegics (111.8±1.9/62.1±1.1 mm Hg) but not in paraplegics (116.7± 1.4/66.0±1.1 mm Hg), compared with controls (117.1 ±1.3/69.1±1.1 mm Hg), adjusting for gender. This difference was not observed at 1 year. The average night:day SBP in mobilising controls was 86.1±0.7%, differing from paraplegics (94.0±1.5%, P