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。
How does varenicline help people stop smoking?
A patient with COPD who is known to retain CO₂ arrives on 15 L/min oxygen. They are now drowsy with SpO₂ 99%. What is the most appropriate action?
A stroke patient speaks fluently, but the words make little sense, and they do not follow simple instructions. Which type of aphasia is this?
A patient taking amiodarone has gained weight and feels tired and cold. Which blood test is most relevant?
Why do patients usually have a dental review before radiotherapy to the head and neck?
A patient with suspected appendicitis says the pain suddenly eased, but an hour later has a temperature of 38.9 °C, a rigid abdomen and a pulse of 118/min. What does this suggest?
Which advice is correct for a patient taking levothyroxine?
A patient with a central venous catheter needs the line removed. Which position reduces the risk of air embolism during removal of a neck or chest line?
A patient receives repeated nebulized albuterol (salbutamol) for severe asthma. Which laboratory change should the nurse watch for?
手术当晚,一名患者的血红蛋白从 12.5 g/dL 降至 8.1 g/dL(125 降至 81 g/L),心率 118 次/分。最可能的问题是什么?
某练习血气显示代谢性酸中毒,HCO₃⁻ 18 mmol/L。用温特公式求预期PaCO₂(范围的中心),单位 mmHg。
某练习血气显示代谢性碱中毒,HCO₃⁻ 32 mmol/L。用预期 PaCO₂ = 0.7·HCO₃⁻ + 21 求预期PaCO₂。
在这条规则的 II 导联心电图上测量 QT 间期和 R–R 间期,然后用 Fridericia 公式 QTc = QT/∛RR(均以秒计)计算经心率校正的QTc。答案以秒表示,保留三位小数。
这条 II 导联心电图显示二度房室传导阻滞 I 型(文氏现象)。测量未下传 P 波之前最后一个下传搏动的 PR 间期(即最长的 PR),以秒为单位。
On a postpartum unit, which patient is the most appropriate to assign to an LPN/LVN?
A chemical cleaning fluid splashes into a patient’s eye. What should the nurse do first?
答案: A · It partly stimulates and partly blocks nicotine receptors
Varenicline is a partial agonist at nicotinic acetylcholine receptors. It reduces cravings and withdrawal and makes smoking less rewarding. Nausea is common, and patients are asked to report mood changes.
答案: D · Reduce the oxygen to aim for 88–92% and get a blood gas
In patients at risk of hypercapnic respiratory failure, excess oxygen can raise PaCO₂ and cause drowsiness and acidosis. Oxygen is stepped down to a target of 88–92% (for example via a Venturi mask), not stopped abruptly, which could cause dangerous hypoxaemia. An arterial blood gas guides further treatment, which may include NIV.
答案: B · Receptive (Wernicke's) aphasia
Receptive aphasia comes from damage to Wernicke's area in the dominant temporal lobe. Speech is fluent but often meaningless, and comprehension is impaired. Patients are often unaware of their errors.
答案: D · Thyroid function tests
Amiodarone is rich in iodine and can cause both hypothyroidism and hyperthyroidism. Thyroid function is checked before and during treatment. The symptoms here suggest hypothyroidism.
答案: A · It causes dry mouth and raises the risk of decay and jaw damage
Head and neck radiotherapy damages salivary glands, causing xerostomia and dental decay, and can cause osteoradionecrosis of the jaw after extractions. Dental treatment is done first, with careful oral hygiene and fluoride.
答案: D · Perforation with peritonitis
Brief relief can occur when an inflamed appendix ruptures, followed by spreading peritonitis with fever, rigidity and tachycardia. This is a surgical emergency needing urgent review, IV fluids and antibiotics.
答案: A · Take it on an empty stomach, usually before breakfast
Levothyroxine is absorbed best on an empty stomach and is usually taken at the same time each morning. It is normally lifelong, with doses adjusted by thyroid blood tests.
答案: D · Lying flat or slightly head-down, holding the breath or breathing out
A flat or head-down position and a Valsalva manoeuvre or breath-hold raise central venous pressure, reducing the risk of air being drawn in. An occlusive dressing is then applied.
答案: C · A fall in serum potassium
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: C · 出血
下降超过 4 g/dL 并伴心率快,提示持续失血。护士应评估伤口和引流管,监测生命体征并紧急上报。静脉液体造成一定程度的稀释很常见,但不会这么多,也不会伴有心动过速。核对依据: Hemoglobin Test · MedlinePlus (NIH) (2024)
答案: PaCO₂ = 35 mmHg
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: PaCO₂ = 43.4 mmHg
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。
升高是有限度的:仅靠代偿,PaCO₂ 很少超过约 55 mmHg。
答案: QTc = 0.394 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。
在通常上限之内(男性约 0.45 s,女性约 0.46 s)。(394 ms)
答案: 最长的 PR = 0.34 s
房室传导阻滞:逐个标出 P 波,检查哪些 P 波后面跟着 QRS。一度:每个 P 波都下传,PR 恒定且大于 0.20 s。二度 I 型(Mobitz I,文氏现象):PR 逐搏延长,直到一个 P 波未下传,然后周期重新开始(成组搏动)。二度 II 型(Mobitz II):下传搏动的 PR 保持恒定,P 波突然不下传;QRS 常增宽。三度(完全性)阻滞:P 波和 QRS 波群各自规则但互相独立,PR 随机变化,心房率快于逸搏率(交界性逸搏 40–60 次/分,QRS 窄;室性逸搏 20–40 次/分,QRS 宽)。2:1 阻滞仅凭一份条带无法判断是 I 型还是 II 型。
PR 最大的增幅出现在一组的第一个和第二个搏动之间;之后的增幅较小,这就是暂停之前 R–R 间期缩短的原因。
答案: C · Day 1 after an uncomplicated vaginal birth, stable vital signs
A stable patient after an uncomplicated birth fits the LPN/LVN role. Heavy bleeding, magnesium infusions and new admissions with fever need RN assessment.
答案: C · Flush the eye with plenty of water or saline straight away
Chemical eye injuries are treated by immediate, continuous irrigation with large amounts of water or saline. Delay, rubbing or a patch allows more damage.
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