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。
A patient taking simvastatin drinks a large glass of grapefruit juice every morning. Why is this a concern?
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?
为什么脊髓损伤后常教患者间歇性自我导尿?
一名卒中并右侧肢体无力的患者准备从床转移到椅子上。哪种方法最安全?
为什么上消化道出血患者的尿素升高可能比肌酐升高得多?
一名乳腺癌患者出现意识混乱、口渴、便秘和多尿。应考虑哪种肿瘤急症?
A patient with Guillain–Barré syndrome has weakness spreading upwards from the legs. Which monitoring is most important?
Why must severe chronic hyponatraemia be corrected slowly?
A patient with chronic kidney disease receives an erythropoiesis-stimulating agent such as epoetin alfa. Which assessments are most important?
A young adult has fatigue, bruising and fever. The white cell count is 85 × 10³/µL with many blasts, the hemoglobin is 7.9 g/dL (79 g/L) and the platelets are 22 × 10³/µL. What is the most likely diagnosis?
练习数值:Na⁺ 136 mmol/L,葡萄糖 6.7 mmol/L,尿素 16.9 mmol/L。计算血清渗透压 Osm = 2·Na⁺ + 葡萄糖 + 尿素,取最接近的整数。
在海平面,某练习血气取自吸入 30% 氧气时,显示 PaO₂ 93 mmHg (12.4 kPa),PaCO₂ 45 mmHg (6.0 kPa)。用 PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 求A–a 梯度。
解读这条 II 导联心律条带。这是什么节律?点击你的答案。
这条 II 导联心电图显示房室传导阻滞,所以心房和心室以不同的频率搏动。QRS 波群是规则的:求出心室率(单位:次/分,1500 法,取整数)。
A patient uses patient-controlled analgesia (PCA) after surgery. Which statement by a family member shows a need for further teaching?
A victim heavily contaminated with an industrial chemical arrives at the emergency department with stable vital signs. What should happen first?
答案: A · It raises statin levels and the risk of muscle damage
Grapefruit juice inhibits the CYP3A4 enzyme, increasing levels of drugs such as simvastatin and some calcium channel blockers. Higher statin levels raise the risk of myopathy. Patients are advised to avoid large amounts or choose a statin not affected.
答案: C · 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: D · 膀胱可能无法排空,定期排空可保护肾脏
脊髓损伤常引起神经源性膀胱。定期清洁间歇导尿可排空膀胱,防止高压,减少感染和肾损伤,并避免诱发自主神经反射异常。
答案: D · 把椅子放在左侧,并向椅子方向转身
向较强的一侧转移更安全,这样患者可以用健侧腿负重并转身。拉扯无力的手臂可引起肩关节半脱位和疼痛。应遵循物理治疗师的建议并使用合适的辅助器具。
答案: D · 被消化的血液是蛋白质负荷,会使尿素升高
被消化的血液是大量的蛋白质负荷,因此尿素升高,往往与肌酐不成比例。低血容量也可使尿素升高。尿素升高是 Glasgow-Blatchford 评分等风险评分的一部分。
答案: A · 恶性肿瘤相关高钙血症
恶性肿瘤相关高钙血症引起口渴、多尿、脱水、便秘、恶心、意识混乱和心律失常。治疗是先静脉补液,然后使用双膦酸盐,并监测钙和肾功能。肿瘤溶解引起的是低钙。
答案: C · Breathing function, such as forced vital capacity
Guillain–Barré syndrome can paralyse the respiratory muscles. Serial vital capacity measurements help identify patients who need ventilation before they deteriorate.
答案: A · Too-rapid correction can cause osmotic demyelination in the brain
In chronic hyponatraemia brain cells adapt to the low tonicity. A rapid rise in sodium draws water out too fast and can cause osmotic demyelination, so the correction rate is limited and sodium is checked often.
答案: C · Hemoglobin and blood pressure
Epoetin stimulates red cell production. Hemoglobin is monitored, because raising it too high increases the risk of hypertension, stroke and thrombosis. Blood pressure is monitored, and iron stores are checked, since iron is needed for a good response.核对依据: Erythropoietin Stimulating Agents · StatPearls (NCBI Bookshelf) (2024)
答案: A · Acute leukemia
Many circulating blasts with anemia and thrombocytopenia suggest acute leukemia: malignant cells crowd out normal production in the marrow. Despite the high white count, the patient has few working white cells and is at high risk of infection and bleeding.核对依据: Laboratory Evaluation of Acute Leukemia · StatPearls (NCBI Bookshelf) (2025)
答案: Osm = 296 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: A–a 梯度 = 64.65 mmHg
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: 室上性心动过速(SVT)
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。 窄 QRS 心动过速与停顿:室上性心动过速(SVT)是规则的心动过速,约 150–250 次/分钟,QRS 波群较窄;P 波通常看不到,因为它们隐藏在 QRS 波群或 T 波中。成人静息时的窦性心动过速通常低于约 150 次/分钟,且每个 QRS 前都有可见的 P 波;伴 2:1 传导的心房扑动常在约 150 次/分钟,并显示锯齿波。窦性停搏是指窦房结暂时停止发放冲动:出现既无 P 波也无 QRS 的停顿,其长度不是 P–P 周期的整数倍(恰好两个或三个周期的停顿则提示窦房传导阻滞)。
答案: 心室率 = 42 bpm
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。
2:1 房室传导阻滞:每隔一个 P 波不下传,所以心房率是心室率的两倍。
答案: C · “I will press the button for her while she is asleep so she stays comfortable.”
PCA is safe because a sleepy patient cannot press the button. If someone else presses it, the patient can receive too much opioid and develop respiratory depression.
答案: C · Decontamination before the victim enters the treatment area
A stable, contaminated victim is decontaminated before entering the department, to protect staff, other patients and the victim. Life-saving care may come first only if the victim is unstable.
ExamProblems · examproblems.com/courses/medical-surgical-nursing