What is the appropriate needle gauge for intradermal injection?

Correct Answer: D

Rationale: The correct answer is **D: 26G** because intradermal injections require a fine, short needle to deposit medication or vaccines just below the epidermis without penetrating deeper tissues. A 26G needle is typically 26-gauge with a short bevel (usually ⅜ to ½ inch in length), which allows precise delivery into the dermal layer while minimizing trauma and leakage. The thin diameter reduces discomfort for the patient and ensures proper absorption, as intradermal injections rely on slow diffusion from the dermis into the local capillaries. This gauge is standard for procedures like tuberculin (TB) skin tests or allergy testing, where accuracy in placement is critical. **A: 20G** is incorrect because it is far too large for intradermal injections. A 20-gauge needle is thick and long, typically used for procedures requiring rapid fluid delivery (e.g., IV infusions or blood draws). Using such a large needle for intradermal injection would cause unnecessary pain, increase the risk of bleeding, and likely deposit the medication too deeply into subcutaneous or muscular tissue, compromising the intended immune response or diagnostic accuracy. **B: 22G** is incorrect because, while smaller than 20G, it is still too large for intradermal administration. A 22-gauge needle is commonly used for IM (intramuscular) injections or subcutaneous injections in adults, where deeper tissue penetration is needed. The diameter is too wide to reliably stay within the thin dermal layer, increasing the chance of misplaced medication and patient discomfort. **C: 25G** is incorrect because, although it is closer to the correct size, it is still less ideal than 26G for most intradermal procedures. While a 25-gauge needle can be used in some cases, it may not provide the same precision as a 26G needle, particularly for delicate applications like allergy testing where slight variations in depth can affect results. The marginally larger diameter may also cause more tissue disruption or leakage compared to the finer 26G needle. The choice of needle gauge balances precision, patient comfort, and clinical efficacy, and 26G is the optimal selection for intradermal injections due to its fine diameter and shallow penetration capability.

Correct Answer: D

Rationale: The correct answer is D (600 mg) because 1 grain (gr) is equivalent to approximately 64.8 milligrams (mg). For practical clinical purposes, this is often rounded to 60 mg per grain for ease of calculation. Multiplying 10 gr by 60 mg/gr yields 600 mg. This conversion is standard in pharmacology, ensuring accurate dosing for medications like aspirin, where precision is critical. Choice A (0.6 mg) is incorrect because it represents a drastic underdose, likely resulting from a miscalculation where 10 gr was divided by 60 mg/gr instead of multiplied. This would be a 1000-fold error, rendering the dose therapeutically ineffective. Choice B (10 mg) is incorrect because it assumes a 1:1 conversion between grains and milligrams, which is not accurate. Grains are a much larger unit than milligrams, and this answer would also lead to a severe underdose, failing to achieve the intended therapeutic effect. Choice C (60 mg) is incorrect because it represents the conversion for 1 grain, not 10 grains. This error occurs if the physician's order is misinterpreted as a per-grain dose rather than the total required dose. While 60 mg might be a standard dose for certain aspirin formulations, it does not meet the 10 gr requirement specified in the question. Understanding unit conversions between grains and milligrams is crucial in medical practice to avoid dosing errors. Grains are an older unit still used in some prescriptions, whereas milligrams are the modern standard. Proper conversion ensures patient safety and therapeutic efficacy, particularly with medications like aspirin, where incorrect dosing can lead to treatment failure or toxicity. Always verify calculations and reference conversion tables when in doubt.

Correct Answer: C

Rationale: To determine the flow rate in drops per minute, multiply the ordered volume per hour by the drop factor (100 ml/hour x 15 gtt/ml = 1500 gtt/hour). Then, divide the result by 60 minutes to convert it to drops per minute (1500 gtt/hour · 60 minutes = 25 gtt/minute). Therefore, the correct answer is 25 gtt/minute.

Correct Answer: A

Rationale: Hemoglobinuria is a characteristic sign of a hemolytic reaction to a blood transfusion. Hemolytic reactions can lead to the destruction of red blood cells, causing the release of hemoglobin into the urine, which presents as hemoglobinuria. Chest pain, urticaria, and distended neck veins are not specific signs of a hemolytic reaction and may be associated with other conditions or reactions.

Correct Answer: C

Rationale: Renal failure often necessitates fluid restriction to prevent fluid overload. In renal failure, the kidneys are unable to effectively filter and excrete excess fluids, leading to fluid accumulation in the body. Restricting fluid intake helps manage this condition by preventing further fluid buildup and complications such as edema and electrolyte imbalances.