Sensitivity is the number of people who have a test that is positive that have the thing you are looking for.  In medicine, this is usually a disease.  We like sensitive tests in medicine. The flip side of the same coin is the specificity of a test.  This is the ability of a test, if it is negative, to allow you to confidently assert that the patient does not have a disease.  We like specific tests in medicine too, we really like them in Emergency Medicine. Both of these things can be defined numerically.  That can be helpful when thinking about the result, a ..read more

As an EM Doc you do a lot of tests.  You know about them, and you know that negative tests don’t always rule out a disease, you know that positive tests can be false positives (patients don’t have the disease you are looking for, but the test suggests they do).  You have seen this normogram about likelihood ratios, and maybe even used it once at a teaching day. That Normogram (Faagan’s normogram) is your friend, because it defines the relationship between the possibility of the disease before and after you test for it, based on what you think.  This depends on three things, the ..read more

Speed and efficiency for doctors and AHPs starting out in ED. Lots of people are worried about their speed in EM.  This is the time it takes to see a patient.  In the bad old days (maybe in some places still) junior doctor’s productivity is measured, and commented upon, with prizes for faster doctors (terrible idea) or euphemistic ‘extra support’ available for those who are ‘slow’.  Junior doctors are also generally a relatively high achieving bunch, they want to be seen to be ‘good’ this generates some anxiety, and nearly every doctor I have supervised have said they are worrie ..read more

We have all experienced the ED in the dire state it is in in the morning with a dejected broken night team filing into the handover room, giant waits on the tracker screen, apologies, unsaid recriminations, and the day team.  Girding their loins to sort out THEIR mess.  No one wants us to be in that situation, but this is where we find ourselves every day. We fight against a broken IT system that is literally from a generation ago, specialities that think we are stupid and can be covertly or overtly obstructive, overcrowding caused by dangerously long bed waits, and the constant unre ..read more

What is lactate?  A good medical student will tell you something along the lines of “Lactate is a byproduct of anaerobic respiration that is produced in response to cellular hypoxia secondary to inadequate oxygen delivery.  It is a marker of tissue hypoperfusion and shock” They might go on to say high lactates are correlated with high mortality.  They might colloquially refer to lactate being ‘badness’.  You’d probably look at them moderately stunned, and say they were correct. Oh’s Intensive Care Manual states:  In critically ill patients, lactic acidosis is often due ..read more

So in the last post I established: Lactate is a base. Lactate production retards cellular acidosis. Lactate is produced all the time. Lactate is fuel. I have suggested that the traditional lactate hypothesis “Lactate is a byproduct of anaerobic respiration that is produced in response to cellular hypoxia secondary to inadequate oxygen delivery.  It is a marker of tissue hypoperfusion and shock”  Is not correct. However we all see, and all know that when people are sick their lactates go up, and when their lactates go up they become acidotic. Why is this? There are two reasons. The ..read more

We have all seen a little old lady crumpled onto a hospital trolley. Referred in eye-rollingly from their family who visited the nursing home and meekly say ‘she is more confused than normal’.  Talking to her you think she’s good value, she thinks she’s on a cruise ship, that you’re a terribly nice young man and that you’d make an excellent match for her daughter. You smile, send off a random panel of blood tests and refer her to care of the elderly. Instruct an exasperated nurse to collect a urine sample (how?!?), maybe you catheterise and cannulate her. No one screams and shouts at you ..read more

Presentations to the ED with acute dyspnoea are a bit of challenge.  History, examination and tests are used to decide if people have heart failure, pneumonia, COPD, or something else.  I think diagnosing heart failure in the ED is a particular challenge, as commonly used ED strategies aren’t particularly good tests for LVF. In a pretty robust study of patients with no cardiovascular disease, normal hearts on ECHO, and normal BNP measurements in 2007 the incidence of bibasal creps in the 80-95 age group was 70%. (CI 58-92% p<0.001).  Incidence increases with age with 11 ..read more

There’s a lady in Resus, she’s 46, she’s got a history of mental health problems.  Her husband tells you she’s been gradually more lethargic over the last few days.  He called the ambulance today because he found her on the sofa in the morning mumbling incoherently.  Her observations are okay.  Her ABC’s are okay, she’s got a normal glucose, but when you go to move her arm to cannulate you notice she’s rigid.  Hypertonic all over.  You do what you can of a neuro exam and find she’s got globally increased reflexes.  Her pupils are fine.  VBG is okay acid ..read more

An old man is wheeled into resus.  His GCS hovers around 10.  No carers have come with him, you find out from the paramedics that the care home staff were alerted to a thump as he fell out of bed.  He’s moving all 4 limbs.  His obs are okay.  His CT head is normal.  His VBG shows a Na of 119, but is otherwise okay. This, for me, is a frighteningly common scenario.  It’s also generally managed badly and in variable ways.  Do you give normal saline?  How fast?  What are the risks?  Aren’t you meant to fluid restrict?  What about urine t ..read more