قبل سحب غاز دم من الشريان الكعبري، عمل الممرض اختبار ألن: ضغط على الشريانين الكعبري والزندي، ثم رفع الضغط عن الزندي فقط، فبقيت اليد شاحبة ١٥ ثانية. ما التصرف الصحيح؟

Before radial ABG sampling, the nurse performs an Allen test: both arteries compressed, then only the ulnar released, and the hand stays pale for 15 seconds. What is correct?

1. Sample from this site because the test is normal
2. Do not use this radial artery; choose another site
3. Sample quickly before the hand is affected
4. Recompress the ulnar artery only, then sample

Answer: B) Do not use this radial artery; choose another site. Colour returning within about 5–15 seconds means good ulnar supply. Persistent pallor means poor collateral flow, so that radial artery is not used because injury could leave the hand ischaemic.