Background This Fast Fact discusses subcutaneous fluid infusions, also known as hypodermoclysis (HDC). The use of parenteral hydration in dying patients is controversial and is discussed in Fast Fact #133. While this Fast Fact discusses subcutaneous fluid infusions for purposes of hydration, similar techniques can also be used to deliver medications (see Fast Fact #28).
Historical and Current Practice Hypodermoclysis was a widely accepted route for parenteral hydration in the 1940s and 1950s before falling out of favor after several reports of adverse reactions, likely related to the use of hypertonic and electrolyte-free solutions. Due to its ease of use, and subsequent research demonstrating its safety and efficacy, HDC has become more widely used. In the US, HDC is mostly used in geriatric and palliative care settings, although it is used more widely elsewhere in the world.
HDC vs. Intravenous Hydration Decisions for parenteral hydration in dying patients are complex and individual decision making is paramount. When parenteral hydration is indicated, clinicians are generally faced with a decision to use HDC or intravenous (IV) hydration (see Fast Fact #134).
- Advantages of HDC over IV: Starting and maintaining a subcutaneous infusion catheter is relatively pain-free. It can be done by trained patients or family caregivers, preventing the need for frequent skilled nursing visits or trips to medical centers to maintain a working IV. HDC provides greater potential sites for needle placement (arm, back, abdomen, thighs), and equipment costs are generally lower than with IVs. Subcutaneous catheters can be easily disconnected from IV tubing and re-used later, allowing a patient to receive intermittent fluid treatments. Portable infusion devices are not needed with HDC. HDC infusions may also cause less agitation in patients with dementia versus IV (1).
- Disadvantages: HDC is limited by a continuous infusion rate of 1-2 ml/min or 1.5-3 L/day (2). This is adequate for most clinical situations, and additional catheters can be added if needed. Bolus infusions (up to 500 ml/hour) are possible with HDC, but often require hyaluronidase (see below). Both HDC and IV infusions have similar rates of local adverse events (e.g. erythema, cellulitis) and lifespan of infusion site (3). HDC can be technically difficult in patients with substantial peripheral edema, as well as in cachectic patients with little subcutaneous tissue. Patients and families may have pre-conceived attitudes about greater benefits with IV routes even while acknowledging increased burden (4).
- Equipment needed: Small butterfly needle (usually 22 gauge) or angiocatheter, skin preparation (alcohol or iodine), sterile occlusive dressing, solution bag (saline or saline-dextrose combination), tubing with drip chamber. The use of an electrolyte free solution like 5% dextrose is discouraged due to third-spacing risks which can cause tissue sloughing or rarely circulatory collapse.
- Procedure: After cleaning the local site, insert the needle bevel up into the subcutaneous tissue. Attach to fluid and tubing and cover with occlusive dressing. Select an infusion fluid and set drip rate or fluid bolus. Normal saline (NS) is typically used although half-normal saline or 2/3 D5W in 1/3 NS have been used in clinical practice. Drip rates can be set to 20-125 ml/hour with gravity (no pump required) or 1-2 ml/minute. Some patients may prefer drips set to gravity 24 hours per day at a low rate (e.g. 50 ml/hour), overnight hydration (e.g. 100 ml/hour), or intermittent fluid boluses (e.g. 500 ml). The volume of infusion needed to keep acceptable levels of hydration in many palliative care patients is lower than healthy patients and postulated to be ~1 L/day (5). No evidence exists for the frequency of site change. Some change only when there are symptoms or needle displacement while others choose a fixed time (e.g. every 3 or 7 days) or fluid volume (e.g. every 1.5 L) Teflon cannulas, although expensive, can be used for a week and are helpful for patients who have trouble maintaining a catheter site (6). Local anesthetic creams may be helpful during catheter placement to reduce discomfort, especially in children.
- Recombinant human hyaluronidase: RHH is an enzyme that temporarily lyses the subcutaneous interstitial space to promote diffusion of fluid. It can be used for site discomfort or if a faster rate of absorption is desired. Previous preparations were of bovine origin and were associated with local allergic reactions, anaphylaxis, and pain, making its role controversial. RHH has shown no human allergenicity (7). Recent studies have investigated RHH versus placebo in a randomized trial with gravity-driven infusion. The RHH group showed higher obtainable fluid rates, decreased discomfort, and similar local reactions. Doses of 150 U to 750 U given as steady push prior to the infusion can yield fluid rates of 380 to 520 ml/hour (8).
Cautions Uncommon local reactions include edema, local pain, or erythema. Interventions include slowing the rate, changing the site, or using RHH. Rare complications include cellulitis and vascular puncture. Systemic complications such as pulmonary edema can occur with all types of artificial hydration.
- O’Keeffe ST, Lavan JN. Subcutaneous fluids in elderly hospital patients with cognitive impairment. Gerontology. 1996; 42(1):36-39.
- Berger EY. Nutrition by hypodermoclysis. J Am Geriatr Soc. 1984; 32(3):199-203.
- Slesak G, Schnurle JW, Kinzel E, Jakob J, Dietz PK. Comparison of subcutaneous and intravenous rehydration in geriatric patients: a randomized trial. J Am Geriatr Soc. 2003; 51(2):155-160.
- Mercadante S, Ferrera P, Girelli D, Casuccio A. Patients’ and relatives’ perceptions about intravenous and subcutaneous hydration. J Pain Symptom Manage. 2005; 30(4):354-358.
- Dalal S, Bruera E. Dehydration in cancer patients: to treat or not to treat. J Support Oncol. 2004; 2(6):467-479, 483.
- Macmillan K, Bruera E, Kuehn N, Selmser P, Macmillan A. A prospective comparison study between a butterfly needle and a Teflon cannula for subcutaneous narcotic administration. J Pain Symptom Manage. 1994; 9(2):82-84.
- Yocum RC, Kennard D, Heiner LS. Assessment and implication of the allergic sensitivity to a single dose of recombinant human hyaluronidase injection: a double-blind, placebo-controlled clinical trial. J Infus Nurs. 2007; 30(5):293-299.
- Thomas JR, Yocum RC, Haller MF, von Gunten CF. Assessing the role of human recombinant hyaluronidase in gravity-driven subcutaneous hydration: the INFUSE-LR study. J Palliat Med. 2007; 10(6):1312-1320.
Author Affiliations: Mayo Clinic, Rochester, MN (AK) and University of Texas M.D. Anderson Cancer Center, Houston, TX (EB).
Version History: Originally published October 2009; copy-edited August 2015.
Fast Facts and Concepts are edited by Sean Marks MD (Medical College of Wisconsin) and associate editor Drew A Rosielle MD (University of Minnesota Medical School), with the generous support of a volunteer peer-review editorial board, and are made available online by the Palliative Care Network of Wisconsin (PCNOW); the authors of each individual Fast Fact are solely responsible for that Fast Fact’s content. The full set of Fast Facts are available at Palliative Care Network of Wisconsin with contact information, and how to reference Fast Facts.
Copyright: All Fast Facts and Concepts are published under a Creative Commons Attribution-NonCommercial 4.0 International Copyright (http://creativecommons.org/licenses/by-nc/4.0/). Fast Facts can only be copied and distributed for non-commercial, educational purposes. If you adapt or distribute a Fast Fact, let us know!
Disclaimer: Fast Facts and Concepts provide educational information for health care professionals. This information is not medical advice. Fast Facts are not continually updated, and new safety information may emerge after a Fast Fact is published. Health care providers should always exercise their own independent clinical judgment and consult other relevant and up-to-date experts and resources. Some Fast Facts cite the use of a product in a dosage, for an indication, or in a manner other than that recommended in the product labeling. Accordingly, the official prescribing information should be consulted before any such product is used.