A patient arrives with suspected cardiac chest pain. How soon should a 12-lead ECG be recorded?
AWithin about 10 minutes of arrival
BOnly after the troponin result is available
CThe following morning
DWithin 2 hours of arrival
2.内外科护理:心血管与呼吸困难
Three days after an MI, a patient faints on the commode while straining hard to open the bowels. The heart rate was 42/min at the time. What is the most likely mechanism?
AA vagal response to straining
BLow blood glucose from fasting
CA new pulmonary embolism
DAn allergic reaction to the commode
3.内外科护理:神经、内分泌与肾脏中等
Why are insulin and glucose given together to treat hyperkalaemia?
AInsulin makes the kidneys pass more potassium in the urine
BInsulin protects the heart muscle cells from the potassium
CGlucose binds the potassium in the blood and removes it
DInsulin moves potassium into cells; glucose prevents a hypo
A 12-lead ECG should be recorded and interpreted within about 10 minutes of first contact, because STEMI needs immediate reperfusion. Repeat ECGs are taken if the pain changes or continues. Troponin results take longer and should not delay the ECG.
答案
A · Within about 10 minutes of arrival
2.内外科护理:心血管与呼吸
答案: A · A vagal response to straining
为什么是这个答案
Straining (the Valsalva manoeuvre) can cause a vagal bradycardia and a fall in cardiac output, leading to syncope. After an MI, stool softeners, adequate fluids and avoiding straining are advised. The event is still reported and the patient assessed for arrhythmia or ischaemia.
答案
A · A vagal response to straining
3.内外科护理:神经、内分泌与肾脏
答案: D · Insulin moves potassium into cells; glucose prevents a hypo
为什么是这个答案
Insulin activates the sodium–potassium pump, moving potassium into cells and lowering the serum level within about 15–30 minutes. Glucose is given to prevent hypoglycaemia. The effect is temporary, so potassium must also be removed.
答案
D · Insulin moves potassium into cells; glucose prevents a hypo
答案: D · Spasm of the hand when a blood pressure cuff is inflated on the arm
为什么是这个答案
Trousseau's sign, carpal spasm during cuff inflation, and Chvostek's sign, facial twitching on tapping the facial nerve, indicate neuromuscular irritability from low calcium.
答案
D · Spasm of the hand when a blood pressure cuff is inflated on the arm
9.实验室检查值与电解质
答案: D · A fall in serum potassium
为什么是这个答案
Beta-2 agonists push potassium into cells and can cause hypokalemia, especially at high doses; they also raise blood glucose. For this reason nebulized albuterol is sometimes used as an extra treatment for hyperkalemia.
答案
D · A fall in serum potassium
10.实验室检查值与电解质
答案: D · It raises the risk of acute pancreatitis
为什么是这个答案
Triglycerides are monitored in patients receiving lipid emulsions, because high levels can cause pancreatitis and show that lipid is not being cleared. The result is reported, and the lipid dose may be reduced or held.核对依据:Triglycerides Test · MedlinePlus (NIH) (2024)
节律标准(II 导联):窦性心律每个 QRS 之前都有直立的 P 波,PR 恒定为 0.12–0.20 s,QRS 狭窄:60–100 次/分为正常窦性心律,低于 60 为窦性心动过缓,高于 100 为窦性心动过速。心房颤动:无 P 波,基线呈颤动,R–R 绝对不规则。心房扑动:约 250–350 次/分的锯齿状扑动波,伴固定的传导比例,如 2:1 或 4:1。一度房室传导阻滞:窦性心律,PR 恒定且大于 0.20 s。交界性心律:窄 QRS,40–60 次/分,P 波缺失或倒置(PR 低于 0.12 s,或 P 波在 QRS 之后)。室性早搏(PVC)是提前出现的宽大(0.12 s 或以上)、形态怪异的 QRS,没有 P 波,T 波方向相反,通常有完全性代偿间歇;二联律是指每隔一个搏动就有一个室性早搏。
五个步骤
1. 心率:R–R = 23 个小格,1500 ÷ 23 ≈ 65 次/分。
2. 节律:规则,每个 R–R 均为 0.92 s。
3. P 波:直立,每个 QRS 之前各有一个,形态一致。
4. PR 间期:0.24 s,恒定,长于 0.20 s。
5. QRS:0.08 s,狭窄(低于 0.12 s)。
解读
一度房室传导阻滞
答案
一度房室传导阻滞
14.心电图节律条带解读
答案: 室性心动过速
室性节律:室性心动过速是连续三个或以上宽大(0.12 s 或以上)的波群,频率超过 100 次/分,通常为 150–250 次/分,节律规则,没有相关的 P 波。心室颤动是紊乱、不规则的波形,无法辨认 P 波、QRS 波群或 T 波,也没有可计数的频率。心脏停搏是几乎平直的线,没有心室活动;平直线一定要通过检查患者、导联和增益并换一个导联来确认。在复苏指南中,室颤和无脉性室速是可电击心律,心脏停搏则不是。
五个步骤
1. 心率:R–R = 10 个小格,1500 ÷ 10 ≈ 150 次/分。
2. 节律:规则,每个 R–R 均为 0.40 s。
3. P 波:无法辨认。
4. PR 间期:无法测量。
5. QRS:0.14 s,增宽(0.12 s 或以上)。
解读
室性心动过速
答案
室性心动过速
在复苏指南中,室颤和无脉性室速是可电击心律。这里只是识别练习。
15.优先排序与委派
答案: C · Keep the head of the bed raised to at least 30 degrees
为什么是这个答案
Raising the head of the bed to at least 30 degrees during and after feeding lowers the risk of reflux and aspiration. Lying flat greatly increases the risk.
答案
C · Keep the head of the bed raised to at least 30 degrees