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Intramuscular injection (IM) is installing medications into the depth of specifically selected muscles. The bulky muscles have good vascularity, and therefore the injected drug quickly reaches the systemic circulation and thereafter into the specific region of action, bypassing the first-pass metabolism. It is one of the most common medical procedures to be performed annually. This activity outlines and highlights the role of the interprofessional team in improving care for patients who undergo an intramuscular injection. This activity also summarizes the anatomic landmarks, safety precautionary checklists, the recommended procedural steps, and the complications to be aware of following the procedure. Objectives: Identify the safe anatomical landmarks for intramuscular injection. Describe the technique of intramuscular injections. Summarize the potential complications of intramuscular injection. Review interprofessional team strategies for improving care coordination and communication to advance intramuscular injection and improve outcomes. Access free multiple choice questions on this topic.

Intramuscular injection (IM) is installing medications into the depth of specifically selected muscles.[1] The bulky muscles have good vascularity, and therefore the injected drug quickly reaches the systemic circulation and thereafter into the specific region of action, bypassing the first-pass metabolism.[2] It is one of the most common medical procedures to be performed annually.[3] However, there is still a lack of adherence to recommended guidelines and an algorithm for giving IM among health professionals worldwide.[2] Drugs may be given intramuscularly both for prophylactic (around 5% for immunization) as well as curative purposes (accounting for more than 95% of IM injections).[2] The most common medications given by IM route include: Antibiotics- penicillin G benzathine penicillin, streptomycin Biologicals- immunoglobins, vaccines, and toxoids Hormonal agents- testosterone, medroxyprogesterone[2] Any nonirritant and soluble drugs may be given IM during an emergency scenario.

Common complications: Persistent pain at the site of injection Muscle fibrosis and contracture Abscess at the injection site Gangrene Nerve injury -the sciatic nerve in gluteal injection, the femoral nerve in vastus lateralis injection, the superior gluteal nerve in dorsogluteal injection, the femoral nerve in vastus lateralis injection, radial nerve in deltoid injection Skin slough Periostitis, osteomyelitis Transmission of HIV, hepatitis virus Inadvertent injection of glass particles while using glass vials and ampoules. Vascular injury[13][2] Pain Pain is one of the common complications of intramuscular injection. Effective interventions to relieve pain include: Buzzy was more effective than ShotBlocker.[14][15] Cold spray.[16][17] Palm Stimulator.[18] Topical eutectic mixture of local anesthetics (EMLA).[19][20] Kangaroo care.[21] Manual pressure, rhythmic tapping, acupressure.[22] Virtual reality glasses, distraction cards, optical illusion pictures.[23][24] Ventrogluteal site compared to the dorsogluteal site.[25] Internally rotated foot and Z-track techniques.[26] A slow rate of injection at 10 s/cc.[27] Performing a rapid intramuscular injection without aspiration.[28] Methods found not effective in relieving pain: Vapocoolant, ice packs in pediatric.[29] Cold needle technique. Warming of the injectate[30] The simple step of asking the patient to cough vigorously immediately prior to injection also helps in reducing the pain associated with the procedure. The transmission of the cough impulse is faster than that of the pain impulse traveling through the slow conducting nerve fibers; thereby, it helps in minimizing the impact of the pain threshold perceived by the brain. A systematic review has shown that gender is the only major variable influencing pain during intramuscular injection.[31] Neuropathy The incidence of injection-related neuropathy observed during a national vaccination campaign in Pakistan was 7.1 per 1,000,00.[32] The ventrogluteal region has a better safety profile than the dorsogluteal region.[9][33][34] Mechanisms governing nerve injury: Direct needle injury Compression from external hematoma Ischaemia Scar formation[9] Variables governing the risk of injury include: Anatomical site of injection The length of the needle The angle of injection Positioning of the patient during injection and The expertise of the health personnel[9]

The incidence of injection-related neuropathy observed during a national vaccination campaign in Pakistan was 7.1 per 1,000,00.[32] The ventrogluteal region has a better safety profile than the dorsogluteal region.[9][33][34] Mechanisms governing nerve injury: Direct needle injury Compression from external hematoma Ischaemia Scar formation[9] Variables governing the risk of injury include: Anatomical site of injection The length of the needle The angle of injection Positioning of the patient during injection and The expertise of the health personnel[9] The sciatic nerve, particularly its peroneal division, is the most common nerve injury, with an intrafascicular pattern the most common subtype. Dorsogluteal injections account for a majority of the same. Smaller gluteal muscle volume to sciatic nerve size ratio is a risk variable governing the same. Nearly 90% of patients with sciatic nerve injury are preset with an immediate foot drop. Magnetic resonance neurography shows increased signal intensity and neuroma formation. Electromyography shows signs of acute denervation as well as chronic denervation with reinnervation.[9] Sunderland classification and treatment algorithm: First degree showing reversible conduction block wherein conservative management will suffice, Second-degree showing Wallerian degeneration with reactive fibrosis. They often show slow and incomplete recovery, and therefore neurolysis is often indicated, and Third-degree comprises necrosis and fibrosis, and the chances of recovery are dismal[9] Surgical exploration is recommended only for cohorts with incapacitating or complete deficits without recovery, even at 3 to 6 months. Early surgical intervention prevents fibrosis. If an action potential is observed beyond the lesion, only neurolysis is advised; otherwise, suture or graft repair is advocated.[9] Radial nerve palsy, most occurring above the radial groove, is the second most common form of traumatic injection neuropathy.[10][35] Safe Landmarks The intersection between the anteroposterior axillary lines and the perpendicular line from the mid-acromion point is safe for IM in the deltoid.[36] The safest anatomical point is approximately 7 to 13 cm below the mid-acromion, midway between the acromion and the deltoid tuberosity. The middle of the vastus lateralis is considered safe for injection in the vastus lateralis.[5]

The strict adherence to recommended guidelines and procedural algorithms for IM injections is of paramount importance in assuring effective pharmacokinetics and the pharmacodynamics of the drugs.[7] Thorough knowledge of the specific anatomical landmarks helps minimize the neurovascular complications that harbinger the IM procedures. The strict adherence to aseptic precautionary measures and safe disposal of the used equipment helps minimize the transmission of blood-borne infections. The ventrogluteal site is considered the safest for IM injection due to the thin plane of subcutaneous tissues and the relatively thick bulk of the gluteus medius.[33]

Issues of True IM Injections True intramuscular injections are observed only in 32 to 52%, with the incidence even falling to 8% among females.[37] Female sex, obesity, subcutaneous fat thickness, and injection site play significant roles in governing the same.[4][38][39][40] Ultrasound guidance and proper needle length are key factors in ensuring true IM injections among patients with increased body mass index[BMI].[41] However, there is still ongoing debate over this point.[42] The Practice of Aspiration Prior to Drug Administration Though nurses continue practicing aspirations, most do it for a short duration than the recommended time of 5 to 10 seconds.[6][7][8] Blood aspiration is observed mainly in the dorsal gluteal (15%) and deltoid (12%) injections.[43] The World Health Organization and Centers for Disease Control and Prevention do not recommend it. Aspiration is unnecessary and is now reserved only for dorsogluteal site injections.[7] Use of Filter Needles The syringe filters significantly minimize the risk of glass particle contamination.[44] However, economic constraints, time consumption, and workforce shortages are significant hindrances to its routine practice.[45] The risk increases with larger bore, unfiltered needles (safe with 23G).[46] Vial breakage by neck wrapping with a cotton ball from an outward direction results in low glass particles than the entire ampoule neck wrapping with a gauze pad from an inward direction method.[45] Some of the current nursing practices pertaining to IM injections seem to evolve more like a tradition passing from one generation to the next and based upon Schön’s and Benner's learning concepts.[2][47] Evidence-based nursing practice is pivotal in ensuring patient safety, and regular updates, monitoring, and intervention mapping strategies may help improve practitioners' adherence to clinical recommendations.[6][7][8][48]