Your Daily Meds - 6 December, 2022
Your Daily Meds - 6 December, 2022
Good morning and welcome to your Tuesday dose of Your Daily Meds.
Bonus Review: Imagine you suddenly remove 1L of blood volume from an unlucky patient. What compensatory processes might occur in that patient to maintain effective blood volume, cardiac output and arterial blood pressure?
Answer: Ok so this is a major haemorrhage - about 20% blood volume in an adult. This results in decreased cardiac output and decreased arterial pressure.
This is sensed by -
High pressure baroreceptors in carotid sinus
Low pressure volume receptors in right atrium and great veins
Compensation -
Minimise effective blood volume change, maintain cardiac output
Venoconstriction
Fluid transfer from ISF to plasma
Decreased renal blood flow = decreased urine volume
Increased muscle pump activity in limbs - ‘restlessness’
Maintain arterial blood pressure
Peripheral vasoconstriction
Tachycardia
Ward Call:
The phone rings. 0300. You wake up. Annoyed. Delirious?
Nope, the nurse on the other end of the phone snaps you back to reality:
“Hi Dr, My name is James, I’m the nurse on 3A. I just have a patient I would like you to review for hypotension down to 84/60.”
As you roll off the lounge and start to quicken your step towards Ward 3A:
What questions could you ask of the nurse over the phone to help stratify risk for this patient?
And as you are walking towards the ward, you start thinking, what causes hypotension?
Have a think and meet me further down for the answers and discussion.
Meanwhile in Clinic:
A 40-year-old female with a history of multinodular goitre has booked an appointment to see you in your GP practice. She reports that swallowing foods and liquids is sometimes difficult. When asked to raise her arms until they are beside her face, her face becomes plethoric. Which of the following is least likely to cause this sign?
Aortic aneurysm
Thyroglossal duct cyst
Retrosternal goitre
Squamous cell carcinoma
Small cell carcinoma
Have a think and meet me at the bottom.
Walking the Halls at 0300:
You hurriedly ask the nurse some questions over the phone:
Short Form:
Is the patient symptomatic?
How does the patient look?
What are the patient’s vital signs?
Why were they admitted?
More Comprehensive:
What is the trend of BP?
What is the HR?
What is the RR?
What is the patient’s mental status?
Is the patient clammy or pale?
What is the temperature?
Does the patient have dyspnoea or chest pain? (septic or cardiogenic shock)
Is there any evidence of bleeding? (Haemorrhagic shock)
Has the patient been given any medications in the last hour? (Anaphylaxis)
Does the patient have a rash? (Anaphylaxis or septicaemia)
What was the reason for admission?
While you simultaneously think of some causes of Hypotension:
Shock
Cardiogenic, Hypovolaemic, Obstructive, Distributive (CHOD)
Medications
Antihypertensives, nitrates, sedatives, analgesics, antipsychotics
Anaphylaxis (Distributive Shock)
Autonomic neuropathy
Diabetes, Parkinson’s, Multiple System Atrophy
Vasovagal (neurocardiogenic syncope)
Constitutional (normal for the particular patient)
Artefact of inaccurate automatic Non-Invasive Blood Pressure (NIBP) monitoring
(Adapted from ‘On Call’- Cadogan, Brown and Celenza)
Back to your Clinic:
Key to this question is noting the description of Pemberton’s sign, the plethoric face, after Pemberton’s manoeuvre, raising the arms to beside the face. Pemberton’s sign is indicative of superior vena cava (SVC) syndrome, commonly due to a mass in the mediastinum. It is classically assessed in the monitoring of retrosternal goitre, as the goitre is thought to impinge on the thoracic inlet when the arms are elevated.
Aortic aneurysms, squamous cell carcinomas and small cell carcinomas can all cause a mass effect in the mediastinum, reducing the increased venous return through the SVC when the arms are elevated.
So, of the options presented, a Thyroglossal duct cyst is least likely to cause Pemberton’s sign.
Thyroglossal duct cysts are an important differential diagnosis of neck lumps and are due to the persistence of the embryological thyroglossal duct. The thryoglossal duct is present from the base of the tongue to the sternal notch. For this reason, restrosternal and mediastinal thyroglossal duct pathology is very unlikely.
Bonus: In massive haemorrhage, there is redistribution of the cardiac output. Which organs receive less blood flow? Which organs have maintained blood supply?
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.