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 are beta-blockers often started after a myocardial infarction?
A ventilated patient suddenly desaturates to 82%. The cause is not obvious and the ventilator alarms are sounding. What should the nurse do first?
Why can a patient with an insulin pump develop DKA within hours if the pump stops working?
A patient arrives five hours after the onset of a stroke. A CT angiogram shows a blockage of a large artery in the brain. What is the most appropriate next step?
Dysphagia that started with solids and now includes liquids, with weight loss, most suggests which cause?
Why is folinic acid (leucovorin) given after high-dose methotrexate?
一名患者腹部僵硬如板,因活动会加重疼痛而一动不动地躺着。这提示什么?
Why is a large pleural effusion drained slowly rather than all at once?
A patient with central diabetes insipidus starts desmopressin. Which laboratory result is most important to monitor for an adverse effect?
A patient on IV gentamicin has a trough level above the target, and the creatinine has risen since yesterday. The next dose is due. What is the best action?
练习数值:Na⁺ 129 mmol/L,葡萄糖 29 mmol/L,尿素 16.2 mmol/L。计算血清渗透压 Osm = 2·Na⁺ + 葡萄糖 + 尿素,取最接近的整数。
某练习血气显示代谢性酸中毒:pH 7.31,PaCO₂ 31 mmHg (4.1 kPa),HCO₃⁻ 15 mmol/L。把实测的PaCO₂与温特公式比较。点选你的解读。
解读这条 II 导联心律条带。这是什么节律?点击你的答案。
依次按五个步骤解读这条 II 导联心电图:心率、节律、P 波、PR 间期、QRS 时限。你在哪一步发现第一个异常?点击它。
An Rh-negative mother has just given birth to an Rh-positive baby. What does the nurse expect to give the mother?
一名上消化道出血的患者心率 128 次/分,血压 84/50 mmHg。以下都有医嘱。护士首先开始哪一项?
答案: C · They lower the heart's oxygen demand and reduce arrhythmias
Beta-blockers slow the heart and reduce contractility, lowering myocardial oxygen demand, and protect against arrhythmias. They are particularly beneficial when the ejection fraction is reduced. They are used cautiously in heart block, severe bradycardia, acute heart failure and asthma.
答案: B · Disconnect and hand-ventilate with 100% oxygen while calling for help
When a ventilated patient deteriorates suddenly, bag-valve ventilation with 100% oxygen takes the ventilator out of the picture. The nurse then checks for displacement, obstruction, pneumothorax and equipment failure (often remembered as DOPE) and calls for senior help.
答案: D · The pump gives only rapid-acting insulin, so there is no long-acting reserve
Insulin pumps deliver a continuous flow of rapid-acting insulin. If delivery stops, there is no depot of long-acting insulin, so ketones can rise within a few hours. Patients carry pens or syringes as a backup.
答案: A · Urgent referral for assessment for mechanical thrombectomy
IV thrombolysis is usually given within 4.5 hours of onset. Mechanical thrombectomy for a large vessel occlusion can be done later, typically up to 6 hours and in selected patients up to 24 hours, based on imaging. Time still matters, so referral is urgent.
答案: A · A narrowing such as an oesophageal tumour
Progressive dysphagia, solids first then liquids, with weight loss, is typical of a mechanical obstruction such as oesophageal cancer or a stricture. It needs an urgent referral for endoscopy.
答案: D · To rescue normal cells from methotrexate toxicity
Methotrexate inhibits dihydrofolate reductase. Timed folinic acid bypasses this block in normal cells, reducing toxicity such as mucositis and myelosuppression, while methotrexate levels and kidney function are monitored.
答案: D · 腹膜炎
腹膜炎(常由穿孔引起)会导致肌紧张、腹壁强直以及活动时疼痛加重。这是外科急症。
答案: B · Rapid drainage can cause re-expansion pulmonary oedema
Draining a large volume quickly can cause re-expansion pulmonary oedema, with cough, chest tightness and hypoxia. Drainage is controlled, and the patient is watched closely.
答案: A · Serum sodium, which may fall too low
Desmopressin acts like ADH, so the kidneys retain water. If the patient drinks too much, water retention can cause hyponatremia, which may lead to confusion and seizures. Sodium, weight and fluid balance are monitored.
答案: D · Hold the dose and report the results to the prescriber
A high aminoglycoside trough with rising creatinine means the drug is accumulating, which increases the risk of kidney damage and hearing loss. The nurse holds the dose, reports to the prescriber and asks about hearing changes and tinnitus. Only the prescriber or pharmacist changes the regimen.核对依据: Gentamicin sulfate injection - Boxed Warning (US prescribing information) · Pfizer Medical Information (FDA label)
答案: Osm = 303 mOsm/kg
衍生数值:计算所得的血清渗透压为 2·Na⁺ + 葡萄糖 + 尿素,各值均以 mmol/L 计(葡萄糖和 BUN 以 mg/dL 计时为 2·Na⁺ + 葡萄糖/18 + BUN/2.8);正常约为 275–295 mOsm/kg。P/F 比值是 PaO₂ 除以以小数表示的 FiO₂。海平面的肺泡氧分压为 PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 mmHg,A–a 梯度为 PAO₂ − PaO₂。
答案: 适当的代偿
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: 心房扑动,3:1 传导
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。
答案: 折旧率
每条心电图的五个步骤:1. 心率(300 法或 1500 法;若不规则则用 6 秒法);2. 节律:R–R 间期是否相等;3. P 波:是否存在、在 II 导联直立、每个 QRS 之前各有一个且形态一致;4. PR 间期:0.12–0.20 s 且恒定;5. QRS 时限:低于 0.12 s。五个步骤做完之后才命名节律。正常窦性心律五项全部符合:60–100 次/分,规则,每个 QRS 之前有直立 P 波,PR 0.12–0.20 s,QRS 低于 0.12 s。
答案: D · Rh immunoglobulin within 72 hours
Rh immunoglobulin given within 72 hours of birth prevents the mother from forming anti-D antibodies, which could harm a future Rh-positive baby.
答案: D · 通过大口径套管静脉输液或输血
心动过速和低血压显示低血容量性休克,因此首先恢复循环血容量,按医嘱使用液体或血制品并密切监测。抑酸和内镜检查在复苏进行之后,口服铁剂属于后期恢复。
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