An arterial blood gas shows a low pH, a high PaCO2 and a normal bicarbonate. What does this show?
ARespiratory alkalosis
BRespiratory acidosis
CMetabolic alkalosis
DMetabolic acidosis
4.临床护理困难
A patient suddenly develops a severe "worst ever" headache that reached full intensity within seconds, followed by vomiting and neck stiffness. What should be suspected?
A trauma patient receives 2 L of IV crystalloid. The hemoglobin falls from 13.0 to 11.4 g/dL (130 to 114 g/L), and the vital signs are now stable. Which explanation is most likely?
A raised PaCO2 with a low pH means the lungs are not removing enough CO2, for example from hypoventilation. A normal bicarbonate suggests it is acute.
答案
B · Respiratory acidosis
4.临床护理
答案: A · Subarachnoid haemorrhage
为什么是这个答案
A sudden thunderclap headache suggests bleeding into the subarachnoid space, often from a ruptured aneurysm. It needs an urgent CT scan and neurosurgical input.
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。
五个步骤
1. 心率:6 秒内有 7 个 QRS 波群,× 10 = 70 次/分。
2. 节律:绝对不规则,R–R 在 0.54 至 1.02 s 之间,没有规律。
3. P 波:无;基线上可见细小不规则的颤动波。
4. PR 间期:无法测量。
5. QRS:0.08 s,狭窄(低于 0.12 s)。
解读
心房颤动
答案
心房颤动
12.心电图节律条带解读
答案: 心室率 = 40 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。
A severe headache and visual changes can be signs of severe pre-eclampsia and a risk of eclampsia. Mild ankle swelling, backache and frequent urination are common in late pregnancy.
IV fluids dilute the blood, so the hemoglobin falls even without further bleeding. Ongoing bleeding must still be considered, so vital signs, wounds and repeat hemoglobin values are monitored.