Pulsus Paradoxus

It’s normal for blood pressure to drop when breathing in.

When you breathe in, the negative intrathoracic pressure increases. That basically means the extra force of all the air you’re leeching from the atmosphere pushes on the insides of the body, squishing the important bits of the cardiovascular system. So, the blood flow gushing out to the rest of the body is reduced a bit, referring to the cardiac output emitting from the left side of the heart. Note that venous return to the right side of the heart increases with inspiration.

A drop in SBP<10 is normal during inspiration. When it’s greater than this, it’s pulsus paradoxus. That can happen in things like:

  • croup
    • inflammatory reaction to parainfluenza virus
    • results in airway obstruction, mainly in children because they have smaller airways
    • airway obstruction means even bigger negative intrathoracic pressures
    • this increases left ventricular afterload, which is the force the heart has to push blood against
  • cardiac tamponade
    • heart is compressed
    • leads to reduced cardiac output

References

  1. Olfa Hamzaoui, Xavier Monnet, Jean-Louis Teboul, Pulsus paradoxus
  2. Van Dam MN, Fitzgerald BM. Pulsus Paradoxus. [Updated 2019 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482292/

Diabetic Emergencies

Do the following things, in this order of priority.

  • Dehydration – rehydrate with IV fluids
  • Insulin – to combat hyperglycaemia
  • Electrolytes – potassium shifts are a concern

A simple acronym solves everything. The point is not to let the patient DIE.

The Sad Evils Of Smoked Salmon

Smoked seafood has, unfortunately, been cast into the same category as preserved meats. These traitors have been linked with an increased risk of malignancy. Shun them all!

On the plus side, chicken is still in season(ing). As long as you’re not a greedy pig about it. Moderation, which basically means not over-gorging, is the key to success. That is, health.

References

  1. Egan, S. (2019). Do Lox and Other Smoked Fish Increase Cancer Risk?. Retrieved 29 August 2019, from https://www.nytimes.com/2019/07/26/well/eat/does-lox-and-other-smoked-fish-increase-cancer-risk.html
  2. Meat, Poultry, and Fish: Picking Healthy Proteins. (2017). Retrieved 29 August 2019, from https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/meat-poultry-and-fish-picking-healthy-proteins

Podcast 031: Vascular Surgery With Dr Gabrielle McMullin

Blood vessels are needed to keep the liquid of life pumping throughout our bodies. Bad vessels lead to bad flow, which is undoubtedly a bad thing.

In this episode, Dr Gabrielle talks about vascular surgery, rather interesting stories and workplace injustice.

Podcast

About the guest speaker

Dr Gabrielle McMullin is a consultant vascular and endovascular surgeon with a long list of letters adorning her name: MB BCh BAO FRCSEd FRACS MCh. She is a specialist at The Sutherland and St George Hospitals in Sydney, as well as a mentor for women in surgery.

Dr Gabrielle was born in Uganda, attended school in Hong Kong and studied medicine at Trinity College in Dublin. She then worked in numerous countries, including Ireland, New Zealand, Papua New Guinea, Hong Kong, England and Australia, where she has lived for 25 years. It has been a fascinating journey.

Dr Gabrielle spends what is left of her spare time with her husband and 2 children.

Music credits

Opening and closing auditory experiences by Rupert Keller.

Podcast 030: Anaesthetics With Dr Marie Dreux

Anaesthetics! And the people who do it! They might have a title that’s hard to pronounce, but the ability to guide patients through operations safely remains rewarding.

In this episode, Dr Marie talks about life as an anaesthseticoshcsdokdtist, interesting cases and training advice.

Podcast

About the guest speaker

Dr Marie-Louise Dreux is an Anaesthetics Senior Staff Specialist at St George Hospital, Sydney. She trained at St Vincent’s Hospital and has worked in Alice Springs, Limerick (Ireland) and Basel (Switzerland), as well as St George.

Dr Marie is a keen violinist, playing in NSW Doctors’ Orchestra, Australian Doctors Orchestra and World Doctors Orchestra, as well as a passionate Sydney Swans supporter and member.

Music credits

Chill beats by Professor Phil Poronnik.

Settling The Contradiction In Urination Theory

Conventional medicine teaches that the parasympathetic system, through its powers on detrusor muscle contraction and internal sphincter relaxation, leads to micturition. Meanwhile, the sympathetic system does the opposite so the bladder does not push that sweet, gold urine out but holds it in.

Why, then, do people urinate more when they are nervous?

The pontine micturition centre is indeed an important area, one that struts around like a pompous turkey with its chest puffed out, wearing a mauve suit and a top hat. It certainly affects the desire to urinate. However, it is tempered by the all-powerful prefrontal cortex. That old dog!

The trusty prefrontal cortex: this fine specimen of modern decision-making prevents you from running yellow liquid down your leg, however surreptitiously you think it might be happening, while making small talk at a cocktail party or waiting in line at the post office. In short, it keeps socially inappropriate things from occurring at socially inappropriate times.

When the brain is racked by fear, the prefrontal cortex shuts down just a little, despite that possibly being the time you need it the most. No matter, because logic is replaced by emotion!

When the inhibition goes, so too does the bladder.

References

  1. Arnold, J., McLeod, N., Thani-Gasalam, R., & Rashid, P. (2012). Overactive bladder syndrome – management and treatment options. Retrieved from https://www.racgp.org.au/afp/2012/november/overactive-bladder-syndrome/
  2. Palmer, B. (2011). Can You Be Scared Enough To Pee Your Pants?. Retrieved from https://slate.com/news-and-politics/2011/10/peeing-your-pants-why-do-people-urinate-when-they-re-scared.html
  3. Innervation of the Lower Urinary Tract. (2018). Retrieved from http://vanat.cvm.umn.edu/lut/Innervation.html
  4. Know your brain: Prefrontal cortex. (2014). Retrieved from https://neuroscientificallychallenged.com/blog/2014/5/16/know-your-brain-prefrontal-cortex