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Editor,—We would like to contribute to the excellent review by Mbamalu and Banerjee on the principles and problems of peripheral venous cannulation.1 Although peripheral venous cannulation to allow fluid and electrolyte replacement is mandatory in emergencies and in situations where strict fluid balance is required, it is worth noting that it may not always be necessary. Hypodermoclysis, the technique of correcting fluid deficits by subcutaneous infusion popularised initially in the 1950s, serves as a useful parenteral alternative to intravenous cannulation. Isotonic fluids may be introduced into subcutaneous tissues where the aim is to correct mild to moderate dehydration in elderly patients (especially in a chronic care setting where intravenous access in the infirm and elderly is notoriously difficult), in addition to being a less invasive route of drug administration in palliative management where opioid and antiemetic treatment is frequently warranted.2 Fluid replacement by the subcutaneous route is relatively safe, easier to initiate, demands less nursing time, is more cost effective than intravenous therapy, causes less discomfort, minimises the risk of intravascular infection,3 does not immobilise a limb (since it may be given into anterior abdominal tissues), and has been found to be less distressing for patients.4 The use of hyaluronidase in the infused solution augments the rate of fluid uptake and volumes up to 3000 ml can be delivered over 24 hours.5Evidence suggests that potassium chloride may also be added to the subcutaneous infusion and concentrations up to 34 mmol/l have been given, with the only undesirable effect being that of discomfort at the delivery site.6 The chief technical disadvantages of subcutaneous fluid therapy are local oedema and sepsis at the infusion site, but the reported incidence of the latter is exceedingly low.3 Since the welfare of elderly patients in long term care increasingly represents the core of medical workload in Western populations it follows that hypodermoclysis can be an important parenteral route of fluid administration, and may therefore be incorporated as an additional limb in the instructive algorithm proposed by Mbamalu and Banerjee.
The authors respond:
We appreciate the comments by Drs Gandhi and Patel. The inclusion of hypodermoclysis in the algorithm would certainly be worthwhile and the authors have made a good case for consideration of the procedure.