Sutters et al. 1992;
USA
Downs & Black score=13
Case control
N=15

Population: Mean age = 28 yrs; Gender: males = 15; Level of injury: paraplegia = 6, tetraplegia = 9; Time since injury = 2 mos-1 yr.
Treatment: A high to low sodium diet over 5 days consisting of 90g protein, 90mmol potassium, 300g carbohydrates & sodium each day. Sodium intake was 260mmol/day for days 1 -3, and on days 4 & 5 it was decreased to 20mmol/day. Tetraplegics (DS) were intervention group & paraplegics (IS) served as a control.
Outcome Measures: Total and fractional urinary sodium excretion; Creatinine clearance; Mean arterial pressure;; Plasma concentrations; Plasma renin activity; Plasma atrial natriuretic peptide (ANP) concentration.

• Urine:
• In DS group, renal sodium excretion ↑ during high sodium days, and ↓ during low sodium days was larger than IS group.
• Urine flow was constant in both groups, but always ↑ in DS group.
• Creatinine:
• Similar between both groups, but ↓ for IS group when sodium was ↓.
• Blood pressure:
• Low sodium: IS group constant, DS group 20mmHg ↑.
• ↓ when sodium was initially ↓ in DS group.
• Plasma:
• Plasma sodium concentration remained stable during all days, in both groups.
• ↑ plasma protein concentration in DS group.
• Endocrine responses:
• Plasma renin activity: ↓ on day 3 & ↑ at a quicker rate on day 4 in DS group.
• Plasma ANP: 2-3x ↑ in DS group than IS group for the entire study.