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 IV fluids given cautiously to a patient with heart failure?
A patient with stable severe COPD has a blood gas showing pH 7.37, a raised PaCO₂ and a raised bicarbonate. How should this be interpreted?
Before a haemodialysis catheter is used, why is the lock solution withdrawn from each lumen?
Which patient with a spinal cord injury is at risk of autonomic dysreflexia?
一名急性上消化道出血患者到院时血红蛋白正常。为什么这可能有误导性?
一名患者上臂有环形全层烧伤。未来数小时内,最重要的评估是什么?
Why is it important to prevent hypothermia during and after surgery?
A patient taking dapagliflozin is vomiting and unwell, with high blood ketones and a blood glucose of only 11 mmol/L (198 mg/dL). What should be suspected?
A patient taking phenazopyridine for bladder pain has bright orange urine. What should the nurse know about urine tests?
The nurse teaches a patient with severe neutropenia after chemotherapy. Which statement shows a need for further teaching?
某练习动脉血气显示 pH 7.43,PaCO₂ 48 mmHg (6.4 kPa),HCO₃⁻ 31 mmol/L。原发性紊乱是代谢性碱中毒。代偿到什么程度?点选你的答案。
练习数值:Na⁺ 139,Cl⁻ 95,HCO₃⁻ 8 mmol/L。使用 AG = Na⁺ − (Cl⁻ + HCO₃⁻) 计算 Δ 比值 (AG − 12)/(24 − HCO₃⁻)。保留两位小数。
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 Bazett 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。
请解读这条 II 导联心电图条带。仅凭这一条心电图条带,你能为哪种解读辩护?点击你的答案。
A nasogastric tube has just been placed for feeding. What must happen before the first feed is given?
A patient in labor is receiving oxytocin, and the fetal monitor shows repeated late decelerations. What should the nurse do first?
答案: D · Extra volume can quickly cause pulmonary oedema
In heart failure, the ventricle cannot cope with large increases in preload, so IV fluids can raise filling pressures and cause pulmonary oedema. When fluids are needed, smaller volumes are given with close reassessment of breathing, crackles, JVP, weight and fluid balance.
答案: C · Chronic respiratory acidosis with metabolic compensation
In chronic CO₂ retention, the kidneys retain bicarbonate over days, bringing the pH back towards normal. A normal pH with high PaCO₂ and high bicarbonate is compensated chronic respiratory acidosis. These patients usually have target saturations of 88–92%.
答案: C · It contains concentrated anticoagulant
Dialysis catheter lumens are filled with a concentrated heparin or citrate lock. If it is flushed into the patient, it can cause bleeding or other effects. Catheters are usually accessed only by trained staff.
答案: B · A patient with an injury at T4
Autonomic dysreflexia usually occurs with injuries at T6 or above. Below this level, the body can still control the sympathetic response to stimuli such as a full bladder. Lumbar and sacral injuries do not usually cause it.
答案: D · 只有在液体转移或静脉补液稀释血液后才会下降
在急性出血时,红细胞和血浆一起丢失,因此浓度起初不变。随着液体从组织进入循环以及静脉补液,浓度才会下降。生命体征和临床体征是更可靠的早期指标。
答案: A · 手部的血液循环和感觉
全层焦痂没有弹性。随着水肿的发展,压力升高,可影响循环(胸部烧伤时则影响呼吸)。定期检查脉搏、颜色、毛细血管再充盈、疼痛和感觉,可及早发现这一问题;可能需要焦痂切开术。
答案: A · It increases the risk of wound infection, bleeding and cardiac complications
Inadvertent perioperative hypothermia impairs clotting and immune function and increases cardiac events and wound infection. Patients are warmed actively and their temperature monitored.
答案: A · Euglycaemic diabetic ketoacidosis
SGLT2 inhibitors can cause DKA with near-normal or modestly raised glucose because glucose is lost in the urine. Ketones should be checked in unwell patients on these drugs.
答案: D · The dye can interfere with dipstick color readings
Phenazopyridine is a urinary analgesic dye that turns urine orange-red. It can interfere with color-based dipstick tests, so the laboratory should be told. The color is harmless, but it can stain contact lenses and clothing.核对依据: Urine - abnormal color · MedlinePlus (NIH) (2025)
答案: C · "I'll check my temperature rectally to be accurate"
Rectal temperatures, suppositories and enemas are avoided in neutropenia, because injury to the rectal mucosa can let bacteria into the blood. Prompt reporting of fever, hand hygiene and avoiding sick contacts are correct.
答案: 完全代偿
解读血气(ROME):先看 pH:低于 7.35 为酸血症,高于 7.45 为碱血症。然后找出能解释它的指标。PaCO₂(正常 35–45 mmHg,4.7–6.0 kPa)是呼吸方面的指标,在呼吸性紊乱中与 pH 反向(Opposite)变化;HCO₃⁻(正常 22–26 mmol/L)是代谢方面的指标,与 pH 同向变化(Respiratory Opposite, Metabolic Equal,即呼吸性相反,代谢性相同)。另一个指标显示代偿情况:正常表示未代偿;沿着使 pH 回升的方向异常、而 pH 仍然异常,表示部分代偿;pH 正常而两个指标都异常,表示完全代偿。各实验室的范围略有差异;这些是练习用数值。
临床上还应检查预期代偿:代谢性碱中毒时 PaCO₂ ≈ 0.7·HCO₃⁻ + 21 = 40.7–44.7 mmHg,所以实测 48 mmHg 提示合并呼吸性酸中毒(混合性紊乱)。上面的答案是按 ROME 法的考试分类。
答案: Δ 比值 = 1.5
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。
介于 1 和 2 之间:单纯高阴离子间隙酸中毒。
答案: QTc = 0.5 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。
超过男性(约 0.45 s)和女性(约 0.46 s)的通常上限:延长。(500 ms)
答案: 2:1 房室传导阻滞(类型未定)
2:1 房室传导阻滞:每个 QRS 对应两个 P 波时,没有两个下传的 P 波连续出现,所以无法看出在未下传的 P 波之前,PR 间期是逐渐延长(I 型)还是保持恒定(II 型)。仅凭一条心电图条带,只能称为 2:1 房室传导阻滞;更长的条带或传导比例的改变才能决定类型。QRS 较窄时更可能是 I 型,QRS 增宽时更可能是 II 型,但两者都不能证明。
QRS 较窄时更可能是 I 型,QRS 增宽时更可能是 II 型,但只有更长的条带或传导比例的改变才能决定。
答案: D · Placement is confirmed by an approved method
A newly placed feeding tube can enter the airway without obvious symptoms, so placement is confirmed before anything is given. Methods differ: US practice usually requires an X-ray for a new feeding tube, while UK guidance uses aspirate pH testing (5.5 or below) first, with X-ray if that fails. Air “whoosh” tests and waiting for coughing are not reliable.
答案: B · Stop the oxytocin infusion
Late decelerations point to reduced blood flow through the placenta. Stopping oxytocin reduces contractions; the nurse then turns the patient onto her side, gives IV fluids as prescribed and informs the provider.
ExamProblems · examproblems.com/courses/medical-surgical-nursing