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。
During airway suctioning, when should suction be applied?
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?
A patient with CKD is booked for a CT scan with iodinated contrast. Which measure helps protect the kidneys?
A patient with a new arm fistula says their hand on that side is cold, pale and painful, especially during dialysis. What is the concern?
What does "neoadjuvant" treatment mean?
After two days of large volumes of IV 5% glucose, a postoperative patient becomes confused with a headache. Sodium is 124 mmol/L. What is the likely cause?
After a needlestick injury from a patient known to have HIV, why must the nurse report it immediately?
Why might a patient with diabetes who takes a beta-blocker not notice hypoglycaemia early?
A patient is on an IV insulin infusion protocol in the ICU. How often is the blood glucose usually checked?
Which patient's result should the nurse act on first?
某练习血气显示 PaCO₂ 31 mmHg (4.1 kPa)。利用规则:在急性呼吸性碱中毒中,PaCO₂ 每比 40 低出 10 mmHg,HCO₃⁻ 下降 2 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 7.19,PaCO₂ 76 mmHg (10.1 kPa),HCO₃⁻ 28 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。
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。
识别这条 II 导联心电图上的节律。点击你的答案。
A drowsy patient who has just returned from surgery starts to vomit. What should the nurse do first?
A patient with anorexia nervosa is admitted. Which finding is the priority?
答案: B · Only while withdrawing the catheter
The catheter is inserted without suction and suction is applied as it is withdrawn, with each pass kept short. This limits mucosal trauma and hypoxaemia. The patient is monitored for desaturation and bradycardia.
答案: B · A vagal response to straining
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: C · Good hydration around the scan, often with IV fluids
Iodinated contrast can contribute to AKI in at-risk patients. Good hydration, using the lowest dose needed, avoiding nephrotoxic drugs and checking kidney function afterwards help reduce the risk.
答案: D · Steal syndrome, which needs urgent review
In steal syndrome, the fistula diverts arterial blood from the hand, causing ischaemia: coldness, pallor, pain, numbness or weakness. It must be reported urgently, because severe cases can cause tissue loss.
答案: A · Treatment before the main treatment, often to shrink the tumour
Neoadjuvant chemotherapy or radiotherapy is given before surgery to shrink the tumour, which may make surgery easier or allow less extensive surgery. Adjuvant therapy follows surgery.
答案: B · Hyponatraemia from hypotonic fluids
Once the glucose is metabolised, 5% glucose acts as free water. Surgical stress increases ADH, so sodium falls, which can cause cerebral oedema. The team reviews fluids and corrects sodium carefully.
答案: A · Post-exposure prophylaxis works best when started as soon as possible
HIV post-exposure prophylaxis should be started as soon as possible after exposure, ideally within hours. Occupational health or the emergency department will assess the risk and arrange follow-up testing.
答案: C · Beta-blockers can mask warning signs such as tremor and a fast heart rate
Tremor, palpitations and anxiety in hypoglycaemia are driven by the sympathetic system, which beta-blockers blunt. Sweating is often still present, and patients need to monitor glucose closely.
答案: A · About every hour
IV insulin acts quickly and has a short half-life, so glucose is usually checked hourly (or as the protocol specifies) and the rate adjusted. This reduces the risk of hypoglycemia and keeps glucose in the target range.
答案: A · Hemoglobin 6.4 g/dL (64 g/L) with new chest pain and a pulse of 124/min
Severe anemia with chest pain and tachycardia suggests the heart is not receiving enough oxygen, which needs urgent action, often including transfusion. The other results are mildly abnormal but expected or stable.核对依据: Anemia · StatPearls (NCBI Bookshelf) (2026)
答案: HCO₃⁻ = 22.2 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: 急性
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: QTc = 0.44 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)。(440 ms)
答案: 尖端扭转型室性心动过速
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。
尖端扭转型室性心动过速是与 QT 间期延长相关的多形性 VT。这里只是识别练习。
答案: D · Turn the patient onto their side
A drowsy patient who vomits can aspirate. Turning them to the side lets vomit drain from the mouth; suction and a prescribed antiemetic follow.
答案: B · Heart rate 38/min and potassium 2.8 mEq/L
Severe bradycardia and low potassium can cause fatal arrhythmias. The body-image beliefs and eating behaviors matter, but physiological safety comes first.
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