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21 Oct 2021

ECT4Health - Understanding Kussmaul's Breathing

#KYJ: Kussmauls Breathing

 In this knowing your jargon episode I will discuss the commonly seen rapid breathing pattern seen in acidosis.

I bet you were taught that breathing stimulus was CO2 driven.   Nope.  It’s acid.


Adolph Kußmaul (1822-1902) was a German physician.

He studied his PhD under Professor Rudolph Virchow the renowned “Father of pathology” (and of DVT / blood clot , Virchows triad fame).  You remember the  Virchow perfect storm of Hyper-coagulation, venous stasis ( slow or stopped blood flow in veins) , and damage/kinking of blood vessel walls.....eeeeeneeee hooooo.....I digress.


Kussmaul’s Breathing 

Kussmaul is perhaps most known in medicine for the rapid deep breathing that patients experience with acidosis (notably DKA) .  He also lends his name to the coma that ensues if untreated (Kussmauls coma).


Kussmaul’s sign 

Is a rise in jugular vein distension seen in COPD or pericarditis patients  when taking a deep breath.

 He is even named after a necrotising vascular disease, a  form of polyarteritis (Kussmauls Disease).

 He was an amazing man with many firsts :

  • First to describe dyslexia  in the mid 1870s though he called it “word Blindness”
  • First to describe polyarteritis nodosa
  • First to diagnose blood clots blocking abdominal vessels.
  • First to drain pleural fluid and perform the original gastric lavage (stomach pump) 
  • He invented gastroscopy 
  • First to describe mercury poisoning’s emotional symptoms that preceded physical symptoms.


But above all this, it’s is the amazing work on breathing drive and triggers for breathing, that excites me the most. ... that and Tim Tams.

Other than psychogenic causes, all involuntary tachypnoea (rapid breathing) is caused by acidosis.

Not CO2 elevation or Oxygen deficit. 

As I said before,  I bet you were taught that breathing stimulus was CO2 driven.   Not directly-   It’s actually acid.

Kussmauls breathing is the eponym given to rapid breathing seen in acidosis.   It relates to pH fall in blood which in tern, drops pH in cerebrospinal fluid circulating around the brain .

As pH falls (acidosis) the respiratory centres in the pons and medulla oblongata of your hindbrain (brain stem) trigger breathing muscles to increase respiratory rate, and depth to ‘blow’ off carbon dioxide (CO2).  Co2 binds with water in plasma to form a weak carbonic acid, for this reason, blood trends towards acidaemia (aka acidosis).  We breath, in part to expel co2 to maintain a pH balance or acid/base balance between 7.35-7.45 (arterial) 


If your blood pH falls - acidosis, for literally any reason, the brain stem says - “oh no you dont!!!”  And stimulates more rapid breathing to blow off the only acid you can- CO2.

So now reflect on any acidotic patient you’ve cared for:

  • Septic or shock- lactic acidosis
  • Respiratory distress- Hypercapnic acidosis
  • Hyperglycaemic emergencies - Diabetic ketoacidosis (DKA)
  • Aspririn overdose - salicylic acidosis,
  • Too much normal saline- hyperchloraemic acidosis,
  • *gliflozin overdoses- euglycaemic or hypoglycaemic ketoacidosis.

The list goes on… any or all increases in blood acidity (pH fall ) will trigger the “blow off CO2” alarm, and your patient will breath faster.

 Kussmauls breathing is one of a collection of abnormal breathing patterns all stem I g from the pons.   For this reason, collectively they’re called Pontine breathing patterns.

 More on the others Biot’s and Cheyne -stokes breathing in the next two weeks.   Follow our FB page so you dont miss these Blogs.

 Id love to plug the online Blood Gas series.   A great small bite three part video series with certificate and handouts.   click here