Self-administered subcutaneous fluid infusion at home in the management of fluid depletion and hypomagnesaemia in gastro-intestinal disease

Background and aims: In short bowel fistula and some other gastrointestinal (GI) diseases, salt, water and magnesium (Mg) balance may continue negative despite oral treatment, even in patients with adequate nutritional status. This study describes the use of self-administered subcutaneous fluid infusions (HSCF) to treat this problem. Patients & methods: HSCF was administered to patients with GI failure and adequate macro-nutrient status (BMI) when GI salt, water and magnesium balance continued negative despite optimal diet, drug and supplemental treatment. Mg depletion was confirmed using the Mg load test. Patients were taught to self-administer 0.5–1.0 l 0.9% saline ±0.5 l 5% dextrose ±2–4 mmol MgSO4 subcutaneously by gravity drip during 6–12 h overnight, 3–7 days/week. Water and Na balance were assessed (weight, serum creatinine, urea, Na) at baseline and at 1 and 3 months of treatment, but also monitored carefully during the first few days of treatment. Serum Mg was measured at baseline and at 2 and 4 weeks. Results: In 10 patients (mean age 65.3±13.5 years) Na and water balance was rapidly restored. At baseline, 1 and 3 months, serum biochemical results were: • Urea [2.0–6.0 mmol/l]: 16.4±11.0; 6.3±4.1; 7.0±3.4 mmol/l (P=0.008); • Creatinine [50–120 dcmol/l]: 201±87.8; 102.3±47.9; 171.6±46.4 mmol/l (P=0.01); • Na [135–145 mmol/l]: 134.3±4.6; 139.8±2.7; 141.0±3.9 mmol/l (P=0.014). Eight patients received 8–28 mmol MgSO4/week in the infused fluid. Serum Mg [0.7–1.0 mmol] at baseline, 2 and 4 weeks was 0.49±0.06, 0.79±0.18, 0.83±0.10 mmol/l (P=0.002). Tolerance was good; transient oedema developed in 2 patients, resolved by reducing infusion dose. No patient developed hypokalaemia. Conclusions: Subcutaneous self-administered fluid infusion at home (HSCF) is an easily managed, safe and effective method of restoring and maintaining water, salt and Mg balance in patients with large GI fluid losses but adequate macronutrient status, particularly in the frail or elderly in whom home parenteral nutrition may be difficult.