内外科护理:心血管与呼吸
方法
- 说出问题所在:泵衰竭、动脉阻塞、节律、血栓、气道狭窄、感染或设备问题。
- 先检查危险征象:低氧、低血压、胸痛、新出现的意识模糊、冰冷无脉搏的肢体。
- 让氧疗与患者相匹配:大多数人为 94–98%,有 CO₂ 潴留风险者为 88–92%。
- 把每种药物与其检测和风险联系起来:华法林与 INR,肝素与 aPTT 和血小板,利尿剂与血钾。
- 选择安全的第一步措施,然后升级处理并重新评估。
公式表、每个专题的关键方法步骤和 16 道练习题,完整解答附在最后。
Why is a shock for cardioversion synchronised with the QRS complex?
Four hours after cardiac surgery, the mediastinal drain, which had been draining steadily, suddenly stops. BP falls to 84/60 mmHg, the heart rate rises and the CVP climbs. What should the nurse suspect?
Which finding most suggests fluid overload in a patient with chronic kidney disease?
A patient's potassium is 7.1 mmol/L, and the ECG shows peaked T waves and broad QRS complexes. What is the first treatment?
Which statement about pain relief in acute pancreatitis is correct?
After surgery, a patient says they have "no pain" but grimaces, breathes shallowly and refuses to move or cough. What should the nurse do?
一名患者有绞痛样腹痛、腹胀、呕吐,两天未排便排气。可能的问题是什么?
Which feature best distinguishes delirium from dementia?
When should a blood sample for a digoxin level be drawn to be interpreted correctly?
A patient has sudden episodes of severe headache, sweating, palpitations and very high blood pressure. Which test is most useful to look for the cause?
某练习血气显示 PaCO₂ 25 mmHg (3.3 kPa)。利用规则:在慢性呼吸性碱中毒中,PaCO₂ 每比 40 低出 10 mmHg,HCO₃⁻ 下降 5 mmol/L,以HCO₃⁻ 24 mmol/L 为起点,求预期HCO₃⁻。
某练习血气显示呼吸性酸中毒:pH 7.32,PaCO₂ 64 mmHg (8.5 kPa),HCO₃⁻ 32 mmol/L。利用规则“HCO₃⁻ 每 10 mmHg 升高 1 mmol/L(急性)或 3.5 mmol/L(慢性)”进行分类。点选你的答案。
测量这条 II 导联心电图上的QT 间期,以秒为单位。
识别这条 II 导联心电图上的节律。点击你的答案。
After a hip replacement using a posterior approach, which statement shows a need for further teaching?
Four stable patients need routine morning care. To reduce the spread of infection, which patient should the nurse visit first?
答案: C · To avoid delivering the shock during the T wave
A shock delivered on the T wave (the vulnerable period) can trigger ventricular fibrillation. Synchronisation times the shock to the R wave. In ventricular fibrillation there is no organised QRS, so defibrillation is unsynchronised.
答案: A · Cardiac tamponade from a clotted drain
A sudden stop in drainage with falling blood pressure, tachycardia and rising venous pressure suggests blood is collecting around the heart because the drain is blocked. Tamponade after cardiac surgery is an emergency: the surgeon is called at once and the chest may need to be reopened.
答案: C · A weight gain of 2 kg (4.4 lb) in two days with ankle swelling
Rapid weight gain reflects fluid retention. Oedema, breathlessness, crackles in the lungs and a raised blood pressure are other signs. Daily weights are a simple and reliable way to track fluid balance.
答案: A · IV calcium gluconate
ECG changes mean the heart is at risk. IV calcium is given first to stabilise the myocardium, followed by insulin with glucose (and often nebulised salbutamol) to shift potassium into cells. Binders or dialysis then remove it.
答案: A · Opioids can be used, and good analgesia is a priority
Acute pancreatitis is very painful, and opioids are used as part of multimodal analgesia. There is no good evidence that they worsen the condition. Sedation and breathing are monitored.
答案: B · Explore their beliefs and explain how analgesia aids recovery
Patients may under-report pain because of beliefs, fear of addiction or not wanting to bother staff. Exploring these concerns and explaining that good analgesia helps breathing and mobility supports a shared plan.
答案: A · 肠梗阻
肠梗阻引起腹胀、绞痛、呕吐和停止排便排气。患者通常需禁食,并留置鼻胃管进行胃减压。
答案: C · Delirium starts suddenly and fluctuates, while dementia develops gradually
Delirium develops over hours to days, with fluctuating attention and consciousness, and is often reversible when the cause is treated. Dementia is a gradual, progressive decline. Patients with dementia are at higher risk of delirium.
答案: B · At least 6–8 hours after a dose, often just before the next one
Digoxin distributes slowly from blood to tissues, so a sample taken too soon after a dose is falsely high. Levels are drawn at least 6–8 hours after a dose, commonly as a trough before the next dose.
答案: C · Plasma free metanephrines
These episodes suggest pheochromocytoma, a tumor of the adrenal medulla that releases catecholamines. Plasma free metanephrines (or 24-hour urine metanephrines) are the main screening tests. Hyperthyroidism can cause similar symptoms but usually without these bursts of severe hypertension.
答案: HCO₃⁻ = 16.5 mmol/L
预期代偿:代谢性酸中毒时,温特公式预测 PaCO₂ = 1.5·HCO₃⁻ + 8 ± 2 mmHg;实测值高于该范围提示合并呼吸性酸中毒,低于该范围提示合并呼吸性碱中毒。阴离子间隙 AG = Na⁺ − (Cl⁻ + HCO₃⁻),正常约为 8–12 mmol/L,用于区分高阴离子间隙与正常阴离子间隙代谢性酸中毒;低白蛋白会掩盖升高的间隙(白蛋白低于 4.0 的部分,每 g/dL 加 2.5)。Δ 比值 (AG − 12)/(24 − HCO₃⁻) 约在 0.8 到 2 之间符合单纯高间隙酸中毒(有些教材用 1 代替 0.8),低于此范围提示合并正常间隙酸中毒,高于 2 提示合并代谢性碱中毒。
答案: 慢性
预期代偿:代谢性酸中毒时,温特公式预测 PaCO₂ = 1.5·HCO₃⁻ + 8 ± 2 mmHg;实测值高于该范围提示合并呼吸性酸中毒,低于该范围提示合并呼吸性碱中毒。阴离子间隙 AG = Na⁺ − (Cl⁻ + HCO₃⁻),正常约为 8–12 mmol/L,用于区分高阴离子间隙与正常阴离子间隙代谢性酸中毒;低白蛋白会掩盖升高的间隙(白蛋白低于 4.0 的部分,每 g/dL 加 2.5)。Δ 比值 (AG − 12)/(24 − HCO₃⁻) 约在 0.8 到 2 之间符合单纯高间隙酸中毒(有些教材用 1 代替 0.8),低于此范围提示合并正常间隙酸中毒,高于 2 提示合并代谢性碱中毒。
答案: QT = 0.42 s
QT 与 QTc:QT 间期从 QRS 波群起点到 T 波终点。它随心率加快而缩短,因此要用以秒为单位的 R–R 间期按心率校正:Bazett QTc = QT/√RR,Fridericia QTc = QT/∛RR。多数教科书使用 Bazett 公式;它在心率快时校正过度,此时宜用 Fridericia。各参考标准的界限不同:QTc 男性高于约 0.45 s、女性高于约 0.46 s 通常称为延长,高于 0.50 s 称为明显延长。
粗略的规则:在正常心率下,QT 应小于 R–R 间期的一半(此处 R–R = 0.80 s)。
答案: 室性自搏心律
更多室性心律:尖端扭转型室性心动过速是一种多形性室性心动过速,通常为 150–250 次/分钟,其增宽的波群高度不断变化并围绕基线扭转,先向上几个心搏,再向下。教科书将其与 QT 间期延长联系起来,复苏指南中针对它推荐的药物是硫酸镁。室性自搏心律是一种心室逸搏心律:规则、QRS 增宽(0.12 s 或以上)、无 P 波,频率 20–40 次/分钟(加速性室性自搏心律为 40–100 次/分钟)。单形性室速的增宽波群完全相同,频率超过 100 次/分钟。室颤则是混乱的,没有任何重复的波群。
室性自搏心律是一种逸搏心律:由于上方的起搏点失灵,心室接管了节律。
答案: D · “I will cross my legs when I sit, so I am more comfortable.”
After a posterior hip replacement, crossing the legs, bending the hip beyond 90 degrees and turning the leg inwards can cause dislocation. Raised seats and a pillow between the knees help prevent it.
答案: A · A patient with neutropenia after chemotherapy
When urgency is equal, the nurse cares for the most vulnerable patient first and patients with transmissible infections last. This lowers the risk of carrying organisms to an immunocompromised patient.
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