護理師進行肌肉注射。對於 150 磅的成人，建議針頭規格為何？

肌肉注射（IM injection）的針頭選擇取決於病人的體型、藥物黏稠度及注射部位。對於 150 磅（約 68 公斤）的一般體型成人，使用 22 號（22 gauge）針頭能適當平衡藥物流速與組織損傷；1.5 英寸（1.5 inch）長度則能確保針尖穿透皮下脂肪層，精確進入肌肉組織（如三角肌或臀部肌肉）。若針頭過短，藥物可能殘留在皮下，影響吸收並增加局部刺激。

Needle selection for intramuscular (IM) injection depends on the client's body size, viscosity of the medication, and injection site. For an average-sized adult weighing 150 lb (approximately 68 kg), a 22-gauge needle provides an appropriate balance between flow rate and tissue trauma; a 1.5-inch length ensures the needle tip penetrates the subcutaneous fat layer and accurately enters the muscle (such as the deltoid or gluteal muscle). If the needle is too short, the medication may remain in the subcutaneous tissue, impairing absorption and increasing local irritation.