Ideal body position for epinephrine autoinjector administration.

Area of Science:

• Emergency Medicine
• Pharmacology
• Anaphylaxis Management

Background:

• Epinephrine is the primary treatment for anaphylaxis.
• Intramuscular (IM) delivery of epinephrine is more effective than subcutaneous (SC) delivery.
• Optimal body positioning for epinephrine autoinjector (EAI) administration is not established.

Purpose of the Study:

• To determine if body position (standing, sitting, supine) affects subcutaneous tissue depth (SCTD).
• To assess the potential impact of body position on EAI delivery into the IM space.

Main Methods:

• Adult volunteers (N=51) from a US military medical facility participated.
• Ultrasound measured SCTD of the vastus lateralis in standing, sitting, and supine positions.
• Data on age, sex, and BMI were collected; statistical analyses compared SCTD across positions, sexes, and BMI.

Main Results:

• No statistically significant difference in SCTD was found among standing, sitting, and supine positions.
• Women exhibited significantly greater SCTD than men (2.72 cm vs. 1.10 cm; p < 0.001).
• No significant association between BMI and SCTD was observed.

Conclusions:

• Adult body position does not significantly alter the skin-to-muscle distance in the thigh.
• An ideal body position for EAI administration may not be necessary.
• Prompt epinephrine administration is advised in anaphylaxis, irrespective of patient position.