Your Daily Meds - 14 December, 2022
Good morning and welcome to your Wednesday dose of Your Daily Meds.
Bonus Review: Is capillary blood flow intermittent or continuous?
Answer: Intermittent.
The metarteriole smooth muscles and precapillary sphincters contract and relax intermittently in a process of vasomotion in response to local drops in pO2. So, if the local tissue pO2 drops, then the precapillary sphincters would dilate to allow another round of intermittent oxygenated blood supply to those tissues.
Importantly, the intermittent nature of capillary flow is not due to cyclical changes in blood pressure - those fluctuant changes are smoothed out by the arterioles.
While having a coffee at 0300:
You receive a phone call from the in-charge Nurse on the Medical Ward about a patient of concern with shortness of breath. As you slowly sip your mocha, what questions could you ask over the phone to determine how quickly, if at all, you should finish your coffee?
Pause now. Get a mocha. Sip it. Think of some questions. And meet me further down.
Quick Question:
By approximately what proportion does cardiac output increase in pregnancy?
5%
10%
20%
40%
60%
Meet me at the bottom with your answer.
As you lower your Mocha:
You consider:
Is the patient cyanosed? - Central cyanosis bad and needs urgent review.
How long has the patient had dyspnoea? - Chronic dyspnoea of COPD is less concerning than the sudden onset SOB with chest pain and hypotension eg PE or pneumothorax.
What are the vital signs?
Are there any associated symptoms? - Chest pain (PE, pneumothorax, ACS), fever (sepsis), stridor (upper airway obstruction), facial oedema (anaphylaxis)
What was the reason for admission?
Does the patient have COPD? - Could answer everything and get you back to your coffee sooner.
Does the patient have massive haemoptysis? - Would need urgent review, obviously.
Adapted from ‘On Call’.
Remember, always ask: “How does the patient look?” and believe all Nursing concern. Realistically, new concerning dyspnoea at 0300 should be reviewed quickly…
Quick Answer:
Cardiac output increases by approximately 40% in pregnancy and may double during the second stage of labour with maternal effort. This increase in output (both stroke volume and heart rate) is a result of increased demands by the uteroplacental circulation and other organs such as the renal circulation.
Trade-off: there is reduced peripheral vascular resistance during pregnancy and reduced blood viscosity with anaemia of pregnancy, which partly offsets the increased cardiac work.
Pearl: This hyper dynamic circulation may result in a soft ejection systolic flow murmur at the praecordium.
Bonus: What is autoregulation?
Answer in tomorrow’s dose.
News: I made a little Ward Call Course for you all. It maps out an Evening Ward Call shift and covers a bunch of common tasks that you may need to do, like:
Deteriorating Patients
Heparin Infusions
Fluid Orders
Electrolyte Replacement
Difficult patients - Discharge Against Medical Advice, Ryan’s Rule
End of Life etc
You can find the course page here:
It’s free and always will be. Let me know what you think.
Remember, you are free to rip these questions and answers and use them for your own flashcards, study and question banks.
As always, please contact me with any questions, concerns, tips or suggestions. Have a great day!
Luke.