Volume 3, Document Number 1 • The Online Journal of Knowledge Synthesis for Nursing

Subcutaneous Administration of Heparin:An Integrative Review of the Research

Volume 3 January 19, 1996 Document Number 1

Suzanne C. Beyea, RN, CS, PhDLeslie H. Nicoll, RN, MBA, PhD

Indexing terms: injections, subcutaneous; injections, subcutaneous-equipment-and-supplies; heparin; medication administration,parenteral

Statement of the Practice Problem

(1) The use of prophylactic low-dose heparin therapy for theprevention of venous thromboembolism is a common medicaltreatment. Controversy exists regarding the appropriate sites forthese subcutaneous injections, the techniques for administration,and strategies to prevent complications, such as hematoma, pain,and bruising.

(2) This basic nursing technique, as described in nursingprocedure books and fundamentals texts, does not reflect researchfindings related to the administration of this medicationsubcutaneously. A review of the literature in nursing, medicine,and related disciplines has revealed key elements to be consideredby the nurse when administering subcutaneous heparin including:1) size of the syringe; 2) length and gauge of the needle; 3) useof an air bubble; 4) site; 5) preparation of injection site; 6) angleof injection; 7) aspiration prior to injection; 8) rate of medicationinstillation; and 9) massage of injection site postinjection. Thisintegrative review will address these issues and establishresearch-based recommendations for the procedure.

Summary of Research

(3) The primary focus of the research related to thesubcutaneous injection of heparin has examined procedures thatmight potentially minimize bruising, hematoma formation, andtissue injury as a result of such an injection. Within the researchdesigns, a standard procedure including the angle of injection,needle length, preinjection preparation, and rolling or bunchingthe skin tissue was adopted. The researchers then manipulatedfactors such as syringe size, use of an air bubble, aspiration, orpressure at the site following administration of the injection. Thissummary of the research reflects literature from other disciplinesand researchers examining similar issues related to subcutaneousinjections.

Syringe and needle size(4) Wooldridge and Jackson (1988 [11]) found that a 3 mL

syringe with a 25-gauge needle and 5/8 inch needle, whencombined with other procedures, was effective in reducingbruising and induration following heparin administration. In otherstudies (McGowan & Wood, 1990 [6]; Vanbree, Hollerbach, &Brooks, 1984 [10]), researchers held the syringe and needlelength constant. When considering needle length for theadministration of subcutaneous heparin, it is important toascertain that the needle does not penetrate muscle tissue.

(5) When selecting a needle for a subcutaneous injection,assess the depth of the subcutaneous tissue in the area to beinjected. After performing computed tomography on diabetics,Frid and Linden (1986 [3]) reported that normal weight diabeticsaverage 14 mm of subcutaneous abdominal fat and 6 mm of faton the lateral thigh. The 5/8 inch needle length is 15.9 mm inlength and when used at a 90 degree angle, the resultant injectionmay be given into muscle tissue in normal weight adults.Although this research was performed on diabetic patients, itprovides a beginning basis for making decisions about needlelength and angle of injection.

(6) A filter needle is recommended when drawingmedication up from a vial or ampule to prevent drawing glassor rubber particles into the solution and syringe (Hahn, 1990 [4];McConnell, 1982 [5]). This recommendation applies to all typesof injections whether subcutaneous, intramuscular, orintradermal. As heparin is typically packaged in single-dose ormultidose glass vials, this recommendation is pertinent to thisprocedure.

Administration Technique(7) Researchers have examined the use of an air bubble,

aspiration, or pressure at the site following injection. Brenner,Wood, and George (1981 [2]) found a smaller percentage ofbruises in subjects who received heparin subcutaneously usinga technique that did not include aspiration when compared to onethat included aspiration. Vanbree, Hollerbach, and Brooks (1984[10]) found that bruising was not affected by whether or not aninjection was aspirated. McGowan and Wood (1990 [6]) foundthat aspiration was not a factor in bruising at 48 or 60 hours.

(8) Using an air bubble is often suggested to clear the needleof medication once it has been injected, thereby reducing theleakage of medication along the needle track. Wooldridge and

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Jackson (1988 [11]) reported that a technique that included useof an air bubble resulted in fewer areas of induration and smallerareas of bruising and induration. Vanbree, Hollerbach, andBrooks (1984 [10]) found no difference when an air bubble wasused as part of an injection technique. Additionally, following athorough review of the literature and discussion with syringemanufacturers, Beyea and Nicoll (1995 [1]) found no validreasons for use of an air bubble in modern, plastic syringes. Zenk(1982 [12], 1993 [13]) reported that use of an air bubble canaffect the dose administered by resulting in an overdose ofmedication by at least 5% and as great as 100%.

(9) The traditional site for subcutaneous injection of heparinhas been the abdomen. This tradition is in conflict with researchregarding this issue. Studying 101 subjects who were randomlyassigned to groups, Stewart-Fahs and Kinney (1991 [9]) foundthat there was no difference in bruising at 48, 60, and 72 hoursor APTT four hours after injection when low-dose heparin wasadministered in the abdomen, thigh, or arm. No research basewas found that supported the usual and customary practice ofadministering heparin only in the abdomen.

(10) Examining patient preferences for injections sites, Patel(1991 [7]) interviewed 73 adults receiving low-dose subcutaneousheparin. He reported that 11 (15%) of those adults refused theabdomen as an injection site and another 12 (19.4%) would havepreferred the upper arm as the injection site. Adults who refusedthe abdomen as a site had anticipated higher levels of discomfortfrom injections in that region than those who did not refuse.

(11) Pressure at the injection site with a dry cotton ball oran alcohol swab has been included as part of the standard orexperimental treatment in at least two studies (Vanbree,Hollerbach, & Brooks, 1984 [10]; McGowan & Wood, 1990 [6]).Although this intervention was not specifically examined,McGowan and Wood (1990 [6]) found that injection-associatedbruises were smaller during the study period. They speculatedthat use of a dry cotton ball and pressure may have promotedclot formation and thus influenced bruising size.

(12) Ross and Soltes (1995 [8]) studied the effectiveness ofpreinjection and postinjection ice as a strategy to minimizebruising and disncomfort. Seventy subjects, who served as theirown controls, received two injections of heparin. Before and afterone injection, ice was applied to the injection site. The researchersfound that although ice was not effective in reducing the numberor size of bruises, subjects reported lower levels of pain. For asummary of the research related to the subcutaneous injectionof heparin, see Table 1.

Annotated Critical References

(13) Brenner, Z.R., Wood, K.M., & George, D. (1981 [2]).Effects of alternative techniques of low-dose heparinadministration on hematoma formation. Heart and Lung, 10(4),657-660.

(14) This experimental study examined two different tech-niques for subcutaneous heparin injection and their effects onhematoma formation at the site. During the study period, 33subjects were each given two heparin injections by one of twonurse researchers. The modified technique varied from the

standard technique in that the needle was changed prior toinjection, the skin was allowed to dry before inserting the needle,the angle of injection was 90 degrees rather than 45 degrees, theinjection was not aspirated, and after withdrawing the needle thesite was not massaged. The researchers found that 57% ofinjections using the standard technique resulted in hematomas,whereas only 42% of the injections using the modified techniqueresulted in hematoma. Despite some interesting clinical findings,the researchers did not find statistical significance between thetwo different types of injection technique.

(15) McGowan, S. & Wood, A. (1990 [6]). Administeringheparin subcutaneously: An evaluation of techniques used andbruising at the injection site. The Australian Journal ofAdvanced Nursing, 7(2), 30-39.

(16) This study examined the relationship between fourdifferent injection techniques and the bruising at injection siteswhen heparin was given subcutaneously. The researchersexamined the effects of aspiration, pressure at the site followinginjection, and the size of the bruise at the injection site. Thisexperimental study examined 206 subjects who received thevarious injection techniques in a random order, with only 95subjects receiving all four techniques. The researchers found nostatistical difference between the four different techniques interms of outcomes. The researchers reported that clinically thereappeared to be some evidence that pressure at the site minimizedbruising.

(17) Ross, S. & Soltes, D. (1995 [8]). Heparin andhematoma: Does ice make a difference? Journal of AdvancedNursing, 21(3), 434-439.

(18) These researchers examined the effectiveness of pre-and postinjection ice as a strategy to minimize bruising and dis-comfort. Seventy subjects, who served as their own controls,received two injections of heparin. Before and after one injection,ice was applied to the injection site. Data were collected using avisual analog scale to assess pain and visual inspection ofinjection sites. The researchers found that although ice was noteffective in reducing the number or size of bruises, subjectsreported significantly lower levels of pain when ice was usedpostinjection.

(19) Stewart-Fahs, P.S. & Kinney, M.R. (1991 [9]) Theabdomen, thigh, and arm as sites for subcutaneous sodiumheparin injections. Nursing Research, 40(4), 204-207.

(20) This study examined the efficacy of three differentinjection sites for the administration of subcutaneous heparin.One hundred and one subjects were randomly assigned to oneof three groups and received three subcutaneous injections ofheparin in the abdomen, thigh, or arm. Activated partialthromboplastin times were measured before the injections andfour hours after the first injection. Following the injections, theresearchers measured bruising at 48, 60, and 72 hours. Theresearchers found no significant differences in the three injectionsites and recommended that the arm and thigh both be used asadditional sites for giving subcutaneous heparin.

(21) Vanbree, N.S., Hollerbach, A.D., & Brooks, G.P.(1984 [10]). Clinical evaluation of three techniques foradministering low-dose heparin. Nursing Research, 33(1), 15-19.

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* All studies were quasi-experimental in design.

(22) These researchers examined the efficacy of threedifferent heparin injection techniques. Forty-three subjects, eachserving as their own control, received the three injectiontechniques. The injection techniques held constant proceduressuch as skin preparation, site, medication and syringe, angle ofthe needle, and postinjection skin care. The techniques onlyvaried in terms of whether or not an air bubble was used or asite was aspirated. The researchers reported that the severity andextent of bruising was not affected by the use of an air bubbleor whether or not a site was aspirated.

(23) Wooldridge, J.B. & Jackson, J.G. (1988 [11]).Evaluation of bruises and areas of induration after two techniquesof subcutaneous heparin injections. Heart and Lung, 17(5), 476-481.

(24) This experimental study examined two differentinjection techniques for subcutaneous heparin and their effectson induration and bruising at the injection sites. During the studyperiod, a researcher administered two heparin injections usingtwo different techniques to 50 subjects. No significant differencewas found in the incidence of bruising for the two injectiontechniques. The researchers reported that subjects receivinginjections using a technique that included a change of needle,use of an air bubble, and a dry sponge after injection experiencedsignificantly smaller areas of bruising and induration.

Practice Implications

(25) The subcutaneous administration of heparin has beena popular medical treatment since 1966. Since that time, nurseshave relied on tradition to provide the basis of practice for thisparticular procedure. In fact, extant research-based knowledge hasnot been reflected in nursing textbooks or procedure manuals.Sufficient research does exist to make a number of practicerecommendations and develop the following standard practiceprotocol.

(26) When administering heparin subcutaneously to adults,use a 25-gauge needle so as to minimize tissue injury andsubcutaneous leakage. The needle length should be selected basedon the patient’s body mass, the intended angle of injection, andthe planned site. For lean adults, if the angle of injection is 90degrees, then the needle should be 3/8 inch or shorter. If the angleof injection is 45 degrees, then the needle length could be as longas 5/8 inch.

(27) A 3 mL syringe should be used whenever possible.Volumes less than 0.5 mL require a low-dose syringe such as atuberculin syringe (Zenk, 1982 [12]). A filter needle should beused to draw up the medication from a vial or glass ampule. Hold

Author and Date Sample* Findings

Brenner, Wood, & George 33 patients - each served as own Standard injection technique resulted(1981 [2]) control for standard and modified in more large hematomas when

injection techniques compared to modified injectiontechnique.

McGowan & Wood 161 patients - 59% of subjects No statistical difference demonstrated(1990 [6]) received four different injection related to bruising between the four

techniques techniques used.

Ross & Soltes 70 patients - subjects served as Ice had no effect on size or occurrences(1995 [8]) own control of hematoma, but patient’s perception of

pain was less.

Stewart-Fahs & Kinney 101 patients - randomly assigned to No statistical differences found among(1991 [9]) one of three groups groups for bruising at 60 and 72 hours

postinjection and APTT (activated partialthromboplastin time).

Vanbree, Hollerbach, & Brooks 43 patients who served as their own None of the three techniques was(1984 [10]) control and received three different statistically significant in terms of

injection techniques smaller or fewer bruises.

Wooldridge & Jackson 50 patients who served as their own Technique using a 3 mL syringe with a(1988 [11]) control and received two different 25-gauge, 5/8 inch needle, a change of the

injection techniques needle, use of an air bubble, and use of adry sponge resulted in a few areas ofinduration and smaller areas of bruisingand induration.

Table 1: Research Addressing Subcutaneous Heparin Administration

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(29) The abdomen, thigh, or arm can be used as an injectionsite for subcutaneous heparin (Stewart-Fahs & Kinney, 1991 [9]).The area selected should be carefully assessed and free ofinduration, abscess, or bruising. The tissue should be rolled orbunched between the thumb and forefinger to ensure that theheparin in injected subcutaneously. The angle of injection shouldbe 45 degrees whenever: 1) the patient has a lean body type; 2)the patient has subcutaneous wasting; 3) a needle longer than 3/8inch is used; or 4) the site of injection is the lateral thigh in anormal weight adult.

(30) The skin should be cleansed with alcohol in a circularfashion in an area of approximately 5 to 8 cm and allowed todry. Alcohol tracked through the skin and into the subcutaneoustissue can be irritating and cause pain. When the alcohol is dry,the needle should be inserted with a steady pressure and thesyringe should not be aspirated. The medication should beinjected at a slow, steady rate so as to promote comfort andminimize tissue damage.

(31) Once the medication is injected, the needle should beslowly and smoothly withdrawn. Gentle pressure with a drysponge should be applied to the site. Whenever possible the siteshould be assessed after the injection and any redness, swelling,pain, or other iatrogenic effects from the injection should benoted.

Research Needed

(32) Although commonly practiced, the basic procedure forsubcutaneous heparin administration is bound by tradition.Certain practice recommendations seem clear, but many otheraspects of the procedure need to be researched more thoroughly.Clinical research is needed to enhance our understanding of howto best minimize negative outcomes.

(33) Some research questions include:(34) What is the optimal needle length and angle of insertion

to minimize bruising?(35) What is the depth of subcutaneous fat in both normal

weight and obese nondiabetic clients?(36) What are the effects of using a concentrated solution

of heparin in terms of bruising?(37) What are clients’ perceptions of bruises resulting from

subcutaneous injections?

the vial down and do not draw up the last drop in the container.Both of these procedures will prevent glass and rubber particlesfrom being drawn into the solution and syringe. Once themedication has been drawn up, the needle should be changedprior to injection. Changing the needle will prevent tracking ofthe medication through the subcutaneous tissue during insertionof the needle, which can result in pain and tissue injury.

(28) Once accepted as a common procedure, the use of anair bubble for any injection is an area of controversy andconfusion. Modern disposable syringes are designed to deliveran accurate dose without an air bubble. Zenk (1982 [12], 1993[13]) found that an air bubble in a syringe can affect the dosageby 5% to 100%. These factors make it clear that an air bubble isan outdated and unnecessary procedure.

1. Beyea, S.C. & Nicoll, L.H. (1995). Administration ofmedications via the intramuscular route: An integrativereview of the literature and research-based protocol for theprocedure. Applied Nursing Research, 8(1), 23-33.[MEDLINE Reference]

2. Brenner, Z.R., Wood, K.M., & George, D. (1981). Effectsof alternative techniques of low-dose heparin administrationon hematoma formation. Heart and Lung, 10(4), 657-660.[MEDLINE Reference]

3. Frid, A. & Linden, B. (1986). Where do lean diabeticsinject their insulin? A study using computed tomography.British Medical Journal, 292(6536), 1638. [MEDLINEReference]

4. Hahn, K. (1990). Brush up on your injection technique.Nursing 90, 20(9), 54-58.

5. McConnell, E.A. (1982). The subtle art of really goodinjections. RN, 45(2), 25-35.

6. McGowan, S. & Wood, A. (1990). Administering heparinsubcutaneously: An evaluation of techniques used andbruising at the injection site. The Australian Journal ofAdvanced Nursing, 7(2), 30-39. [MEDLINE Reference]

(38) Are there postinjection procedures such as icing orpressure that will minimize bruising?

(39) How does age or health status affect bruising,hematoma, or discomfort?

(40) How does use of an alcohol swab following an injectionaffect bruising?

(41) If nurses are taught a research-based protocol for thesubcutaneous administration of heparin, will they practice it andwill that practice affect outcomes in a positive manner?

Search Strategies

Search terms(42) injections, subcutaneous; subcutaneous heparin;

heparin; subcutaneous injections-equipment and supplies;subcutaneous injections; adverse effects

Databases used(43) CINAHL (1983-6/95) - English only(44) MEDLINE (1/66-6/95) - English only(45) RNDex 100 (1992-7/95)

References

Volume 3, Document Number 1 • The Online Journal of Knowledge Synthesis for Nursing

7. Patel, K.S. (1991). Patients’ preferences for the site ofinjection of low-dose subcutaneous heparin in prophylaxis ofthromboembolism. Regional Acuphobia. British Journal ofClinical Practice, 45(1), 26-27. [MEDLINE Reference]

8. Ross, S. & Soltes, D. (1995). Heparin and hematoma: Doesice make a difference? Journal of Advanced Nursing, 21(3),434-439. [MEDLINE Reference]

9. Stewart-Fahs, P.S. & Kinney, M.R. (1991). The abdo-men, thigh, and arm as sites for subcutaneous sodium heparininjections. Nursing Research, 40(4), 204-207. [MEDLINEReference]

10. Vanbree, N.S., Hollerbach, A.D., & Brooks, G.P. (1984).Clinical evaluation of three techniques for administering low-dose heparin. Nursing Research, 33(1), 15-19. [MEDLINEReference]

11. Wooldridge, J.B. & Jackson, J.G. (1988). Evaluation ofbruises and areas of induration after two techniques ofsubcutaneous heparin injections. Heart and Lung, 17(5),476-481. [MEDLINE Reference]

12. Zenk, K.E. (1982). Improving the accuracy of mini-volumeinjections. Infusion, 6(1), 7-12.

13. Zenk, K.E. (1993). Beware of overdose. Nursing 93, 23(3),28-29.

AUTHOR’S INFORMATION

Suzanne C. Beyea, RN, CS, PhD, is an Associate Professorof Nursing at Saint Anselm College in Manchester, NewHampshire 03102. Telephone: 603-641-7096. Fax: 603-641-7116. E-mail: sbeyea@anselm.edu

Leslie H. Nicoll, RN, MBA, PhD, is a Research Associateat the E.S. Muskie Institute of Public Affairs at theUniversity of Southern Maine in Portland, Maine 04103.Telephone: 207-780-4568. Fax: 207-780-4953. E-mail:lnicoll@maine.maine.edu