ACLS : Bradycardia Differentials

5 04 2021

Differentials for Bradycardia

I am a little biased towards figuring out if the patient had a STEMI or if they are hyperkalemic because those are likely to be immediately life threatening and have drastically different management. Trying to manage Hyperkalemia induced bradycardia with ACLS drugs is not so effective. Hence my most high yield bedside investigations are an Electrocardiogram and point of care potassium (draw carefully to avoid hemolysis)

  1. Cardiac – Sinus node or AV node dysfunction from various etiologies (including STEMI, myocarditis, post-surgery)
  2. Hyperkalemia – most often in ESRF with missed dialysis, but also in acutely ill patients (eg severe dehydration, shock with Acute Kidney Injury)
  3. Drugs – multitude of drugs especially cardiac ones such as beta blockers, Calcium channel blockers, Digoxin, Opioids, Sodium channel blockers. Consider illict drugs and poisonings such as Organophosphate
  4. Neurological causes – raised intracranial pressure (evolving towards a Cushing’s Triad), Neurogenic Shock (taking out the sympathetic drive)
  5. Others – Hypothyroidism, Hypothermia, Hypoxia
  6. Infectious diseases – typhoid etc (not common in Singapore) especially if disproportionate to fever
  7. Periarrest – any critically ill patient can decompensate and become suddenly bradycardic.

Some other causes to consider

  1. Conditioning – athletes with high vagal tone, many know their resting heart rates
  2. Vagal response – to pain, emotional distress – recovers within minutes

Always consider and investigate the most critical causes first before suggesting a benign cause.


  1. emDOCS – An Approach to Bradycardia in the Emergency Department
  2. Circulation – Part 7.3: Management of Symptomatic Bradycardia and Tachycardia

ACLS : Transcutaneous Pacing

6 02 2021

Pacing 101.

  1. Sedation and analgesia.
    My personal preference is a combination of fentanyl and midazolam. If your patient is awake – briefly explain the procedure to them and get their consent if possible.
  2. Use the pads.
    The paddles are going to be harder to hold. Make sure that the pads and the 3 leads are via the same machine. If your bay/bed has a monitor + defibrillator and you separate the monitoring and pacing – it won’t work. Also prep the chest for appropriate contact – clip excess hair (avoid shaving), wipe off excess fluids, move jewelry aside, keep medical devices away and remove any drug patches. Anterior Posterior position is preferred.
  3. Switch to pacing mode and choose fixed.
    I cannot find any sources mentioning which mode is superior. Demand mode is useful if the patient has an intermittent perfusing rhythm, in the ED we often just use fixed mode. The pacing mode is also sensitive to good sensing eg if there’s artifacts because of poor contact with the pads, this might go haywire.
  4. Set a rate.
    I like to use 60-80bpm.
  5. Set an output.
    The sicker your patient, the higher you want to start, you can do 70-80 mA and adjust accordingly. Aim to be 10-20 mA above the minimum to maintain that pacing (eg if the patient moves and there’s poor contact etc)
  6. Check for capture.
    This should be both electrical (a pacing spike is consistently followed by a waveform) as well as mechanical (a consistent pulse is felt – preferably distally to avoid the confusion from the muscle twitch, as well as an improvement in the hemodynamics)
  7. Call your friendly cardiologist.
    The patient may need to be on transvenous pacing, an urgent angiography / angioplasty or even a permanent pacemaker. Most of these patients need to be in a cardio High Dependency or Intensive Care Unit anyway.

Further Reading :

Physio-Control Manual on Non-invasive Pacing

Internet Book of Critical Care – Bradycardia

“I have more morphine than you have pain”

14 06 2015

… said the lecturer to a hypothetical patient during our lecture on kidney stones. He indirectly admonishes our management of pain, an issue that is well studied and one which I had fruitful discussion with Andrew Coggins online. It is extremely satisfying to have a person, screaming and shouting in pain, respond to a good dose of morphine.

So now, I’m at a point in my career where you start taking things for granted. Where, you tend to start seeing things as “work” and the time when you first put your stethoscope to someone’s chest and gushed about being able to hear a heart beat are long gone.

This documentary shakes your out of that complacence and reminds you of the discoveries that changed the course of human history and medicine. How chemists worked hard distilling opium into a reliable morphine and tried it out on their pets, assistants and themselves, about the patients who gladly (and sometimes reluctantly) offered themselves as test subjects. It covers a whole lot of ground from the history of pain management, the surprising butterfly effects triggering(coca cola anyone?) their discoveries and the story of how these drugs eventually got out to the public.

Early on in the documentary, Druin Burch talks about his impressions of an early, failed demonstration of inhaled anesthesia –

“No one had imagined that anesthesia could exist and I think that’s why Wells failed in his demonstration of nitrous oxide because they found the very idea that pain was optional, that pain could be deleted, erased from the world, so intrinsically fraudulent that they were predisposed to reach that conclusion.”

Which makes you wonder, what blind spots might we be having today?

Experiment Number 2 in Cold Brew Coffee

5 04 2015
I first got into cold brewing after a visit to a tea shop in Hong Kong which suggested I could drench my tea leaves in cold water to let them soak before dunking them into hot water. I liked the flavour that produced and my further online reaearch suggested that I could actually go all the way and cold brew tea by soaking tea leaves in a cup overnight in a fridge. That produced a perfect flavour profile (strong, but just short of acidic) for a tea I got from Taiwan. It was convenient too, because I could leave it in the fridge for a couple of hours and drink it,  without having to pay attention to how long I was brewing it while heating the water.
I tried the cold brew experiment a month or two back with a bag of ground coffee from Highlander. I watched a couple of youtube videos, including the one on Jamie Oliver’s channel. I emptied an entire 250g of ground beans into the jar and topped it up with abotu 750 mls of water. I let the jar sit in the fridge overnight before the excruciating process of filtering the ground from the finished product. I used multiple Boncafe’s filters (the 4-6 cups one)  for the entire batch and ended up with a strong concoction (which, not knowing how to dilute, left me jumpy and tachycardic for the evening) it did keep me up for an entire night of partying though. What’s bothered me so far is how the cold brew (or anything short of a properly, foamy latte) lacks a kind of fullness to the sip, but I’ve given up trying to achieve that.
This time round, I decided to try it again, with the intention of using the coffee concentrate for something else. I used about 100gm of coffee power (Kaffe Kaldi’s French Roast) in around 800mls of water. Let it soak for 24 hours and filtered it out (nothing fancy, just a strainer and 6 pieces of filter funnels, consecutively) to come up with the final product that you see on my instagram. The difference between this batch and the previous one, I recall specifically that the KK grounds sank to the bottom while the Highlander ones were mostly floating on the surface. Again, since I do not recall the previous flavour profile, I can’t say for sure how that might have affected the taste.
Co-incidentally, Coffee:Nowhere was hosting a little fair at West Coast Plaza and had some of their cold brews for sale, so  I decided to buy a bottle for comparison’s sake. I cannot recall how my previous batch tasted like and I’m not the connoisseur to differentiate the subtle notes (apple, cinnamon, freshly cut rubber hose), there was something definitely different. My coffee had some bitter notes that were upfront lasted throughout. The bottled coffee (“Specialty Blend”, but no other details) had a gentler, smooth acidic note to it.
I’m not sure if cold brew is a hugely different beast from hot brew, because I have never made my own hot brew at home from grounds and when I’m buying some outside, I never have it black, nonetheless, having two samples to compare, the bottled once had actual flavour beyond the acidic note, while mine didn’t. I noticed the colours looked different, so I diluted mine a little and it toned down the bitter, but had basically, very little flavour otherwise. In retrospect, I should probably consider using the full 200g next time.
What am I going to do with my home made jar of cold brew coffee? Follow me on Instagram @csjjjj and see for yourself tomorrow.

Thought Train – What does it really mean to settle down?

27 08 2014

Source – lorenzaccio on flickr

I used to think that to be truly settled down in a place, you need to be comfortable taking the bus. Looking back at my stay in Bangkok where I took a bus to work in an
absolute foreign country and then rented a place where I would start my day with a delightful boat ride to work, I suppose there is some truth to the naivete. Though I
wonder if planning a trip by public transport to a new place is more of a step in growing up rather than settling down per se. When I was much younger, my benchmark for
having grown up, and being able to take care of myself, meant being able to take a bus or train independently in Mumbai.

Taking the train in Mumbai seems like such a struggle in contrast to the ease of movement back at home. 

Thought Train: On going home

26 08 2014

I wonder if home means something else to people who travel a lot. Is it something more special because they have limited access to it? Do they find it easier to make a place their home or harder? I sometimes find it easy to be at home almost anywhere, but I wonder if it has got to do with having stayed in a single spot for many years and it feels like you can relax and make yourself comfortable anywhere because on some instinctual level you know that abode is only temporary.

Which begs the question.

What does it really mean to settle down?

Books! Emperor of All Maladies

3 08 2014


I’m paying a bomb in overdue fines for this book, but it’s worth it. The book has been on my radar from a few years ago after a close friend recommended it, but it wasn’t available on the library’s otherwise fantastic e-book portal so it took a bit of a coincidence to finally get my hands on it.

i started reading it way back in June when I started my surgical oncology rotation. As I was doing a takeover of the patients before starting, one of my colleagues jokingly spoke of the field as being almost Halstedian (a reference that is easy to misconstrue). Halsted is famous for proposing the radical mastectomy, a major, disfiguring surgical procedure involving removal of the breast, the pecs, and lymph nodes in the arm pits. Surgeons of that era noticed a trend of breast cancer recurring in the margins of the previous surgery and this drove them into a frenzy of more and more invasive surgery (including removing lymph nodes around the collarbone, the chest and so on). This turned out to be a bad idea and looking at the data, it didn’t seem to improve life expectancy, yet the story goes that Halsted dogmatically persisted with aggressive surgery against consensus. Despite that Halsted is famous for a number of this as his wikipedia entry attests to.

Siddhartha Mukherjee really paints a lively, colourful picture of cancer’s history, and it looks like the secret to doing that well is to really flesh out the people who made that history. Mukherjee goes a step further to make the science accessible. Now I am clearly biased and I am reading this book as a medical professional and as the title of my blog suggests, always a student at heart. This paragraph, truly embodies how medicine should be taught. not as a bunch of dry facts but as a logical though process, with the appropriate historical context adding colour to the story.

“In 1982, a post doctoral scientist from Bombay, Lakshmi Charon Padhy, reported isolation of yet another such oncogene from a rat tumour called a neuroblastoma. Weinberg christened the gene neu, naming it after the type of cancer harbouring this gene.

The product of the neu gene in contrast, was a novel protein, not hidden deep inside the cell, but tethered to the cell membrane with a large fragment that hung outside, freely accessible to any drug. Lakshmi Charon Padhy even had a “drug” to test. In 1981, while isolating his gene, he hass created an antibody against the neu protein.

Weinberg had an oncogene and possibly an oncogene blocking drug but the twain had never met (in human cells or bodies). In the neuroblastoma cells dividing in his incubators, neu rampaged on monomaniacally, single mindedly, seemingly invincible. Yet its molecular foot still waved just outisde the surface of the plasma membrane, exposed and vulnerable, like Achilles’ famous heel”

I never imagined, during my cancer biology lectures back in med school that Cancer, something that we often see as depressing, morbid and sometimes hopeless, could have a story behind it that’s hopeful, inspiring and quite a scientific adventure.

It’s made me appreciate the training I’ve had and the value of good teachers.

My favourite passage from a Science book

24 03 2014

This passage stuck in my mind after attending the Darwin Day 2014 celebrations and I kept thinking about it when I was sitting at the pond.

“It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” ~ Charles Darwin, The Origin of Species 1859 Edition


I found the tenses on this govt FAQ a little odd

18 02 2014

I was taking a break from studying by browsing the FAQs for MediSave which is a fund set up by the government where you contribute a bit of your salary to so as to help cover medical bills. Here’s what I saw.

medisave tenses


Read the rest of the FAQ  here.

“I wish I could go to bed”

14 02 2014

This came in via Medscape, which a Medical Education/Newsportal most of us subscribe to. It’s a compilation of reflections from the Medscape panel on “Why we practice Medicine”

If you have a subscription, you can see the rest of the slides here.