Blood Aspiration during Intramuscular Injection

Sunday, 27 July 2014: 10:30 AM

Megan A. Infanti Mraz, RN, PhD
Department of Nursing, West Chester University of Pennsylvania, West Chester, PA
Christine Thomas, RN, DNSc
Department of Nursing, West Chester University, West Chester, PA
Lois Rajcan, MSN, RN
Department of IV Therapy, Chester County Hospital, West Chester, PA

Topic: Incidence and prevalence of blood aspiration during Intramuscular (IM) injection.

Intramuscular (IM) injection is a common practice in nursing. The technique whereby   one learns how to administer an intramuscular injection is a practice that is taught very early in a student nurses career. For many years student nurses were taught to aspirate prior to the administration of a medication into the muscle. In recent years, this practice of aspiration had been called into question and subsequently been removed as a recommendation. This has left the academic and professional communities with questions such as: Why is aspiration no longer recommended and are there certain exceptions when aspiration would be necessary?  The authors of this presentation share these questions. Therefore, a study was conducted to  look into the expectations of a nurse in practice, a review of the events in history that may have impacted the practice of aspiration, a review of what is required of a nurse in order to be successful in IM injection, and the conflicts that the profession is faced with today in relation to applying practice that is safe, effective, and rooted in the evidence.

Purpose: The purpose of this presentation is to disseminate findings identified through data gathering and research analysis that occurred in the summer of 2012.

Research questions: Questions guiding the study included: What is the incidence of aspiration during IM injection? What is the prevalence of blood aspiration during the aspiration phase of IM injection? And, what techniques/ methodologies are practicing nurses using during IM injection?

Subject and Sample: 164 staff nurses participated from a community based hospital in Pennsylvania, United States. Majority of the sample consisted of bedside nurses. Specialties in practice, years in practice, and educational levels were varied.

Design and Methods: The research design for this study was a quantitative approach, in the form of a non-experimental one group survey design.

Results: This study has generated new information on the incidence and prevalence of blood aspiration during IM injection. The data identified that despite CDC recommendation (CDC, 2011), 82% of the subject sample maintains aspiration technique during IM injection. Furthermore, over 38% reported to have aspirated blood during their careers when administering an IM injection. Anecdotal data from this study also identified other patient injury such as: infiltration, nerve injury, tissue necrosis, and abscess during IM injection.

Implications: This study has identified that blood aspiration does occur during IM injection. Furthermore, anecdotal information in relation to other patient injury was identified through administration of injection. However, the data also identified concerns related to IM injection and when aspiration can be unsafe.

Future Recommendations for Research and Practice: Based on the prevalence of blood aspiration, and identified patient injury, it is clear that aspiration should be recommended in certain instances. It is possible that aspiration should not be recommended 100% of the time secondary to the concerns regarding aspiration during unsafe conditions.

The infusion nurses’ society recommends that infusions intended to be infused through the vascular system be assessed for a pH of less than 5 or greater than 9 and osmolality of greater than 600mOsm/L. Medications that meet the above pH and osmolality parameters are known to be vesicants or irritants to the vascular system and should be infused through the central circulation (Infusion nurses society, Standard 32, 2011). Human blood has a pH of 7.35-7.45. Many varieties of medications are considered vesicants or irritants based on the definition of pH less than 5 or greater than 9.

Common Medications administered IM such as:

Penicillin G reconstituted has a pH of 6-8.5 (US National Library of Medicine, 2011)

Haldol has a pH of 3-3.6 (FDA, 2009)

Morphine has a pH of 2.5-6.5 (U.S. National Library of Medicine, February)

 Accidental administration of these medications into the peripheral vascular system during an IM injection would cause significant discomfort related to phlebitis or thrombus formation in the vein or artery.

Historically, the aspiration technique was taught as a precaution against accidental intravenous or intra-arterial administration of medications that can potentially lead to systemic allergic reactions (Li, 2003), chemical phlebitis of the vascular system (Infusion nurses society, Standard 47, 2011) or arterial embolism (Gammel, 1927).

Reference to an irritation index of a medication being administered, whether alkaline or acidic, is not a routine consideration during an IM injection. Yet, the infusion nurses society recognizes a pH index for irritation of the vascular system for medications being administered.  Recommendations from this study would include investigation to aspiration prior to IM injections to avoid accidental administration of a potential irritant medication into the vein/artery.


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Infusion nurses society. (2011). Standard 47: Practice criteria: Phlebitis. Journal of infusion nursing: Infusion nursing standards of practice, pp S65-S66.

Li, T., Lockey, R. F., Bernstein, I., Portnoy, J. M., & Nicklas, R. A. (January, 2003 ). Allergen immunotherappy: A practice parameter. Annals of Allergy, Asthma, & Immunology, 1-39.

U.S. National Library of Medicine. (February, 2010). Morphine Sulfate for injection. Retrieved from DailyMed:

US National Library of Medicine. (2011, April). PFIZERPEN (penicillin g potassium) powder, for solution. Retrieved from DailyMed: