MBS Assessment Big Picture Dez Hughes spk12507.jpg D.Hughes@massey.ac.nz lgo12507.jpg The Big Picture Major Body System Evaluation Hi folks! This week’s big picture is about how to develop a standardised way of assessing the emergency patient: what I call the Major Body System Assessment. This lets you rapidly determine how stable or unstable the patient is and then helps you to focus on stabilising the most dangerous problems first. If you’re wondering how to prioritise the problems, you just have to answer one simple question: What’s going to kill it first? Introduction Some cases are difficult! A standardised approach is important because emergency patients vary so much. They may be as happy as Larry or on death’s door and your job is to determine this as quickly as possible. If you always do things the same way, you will feel more comfortable and not forget anything. This fella is Bert, a Lab that I saw at the Royal Vet. College. He was in horrible, hypotensive, septic shock secondary to Strep septicaemia: The so called Flesh Eating Strep. On the right is him at one of his rechecks! And some are more straight forward Sometimes things are more straight forward. Here’s an old Cocker Spaniel intact bitch with a history of anorexia, lethargy, PU/PD, vomiting and a vaginal discharge. MBS assessment if all fine apart from some mild dehydration. You should always keep an open mind but Common Things Are Common and Rare Things Are Rare so this girl has read the textbooks and has a pyometra till proven otherwise. And some are mouthwatering! Once you have honed your MBS assessment then you are ready to assess anything that emergency can throw at you. In fact, your tongue should be hanging out at the prospect of seeing emergencies! There’s nothing wrong with this Boxer, it’s just the biggest tongue I have ever seen! Thought for the day Told to me as a first year student by an elderly professor of anatomy. And how right he was! We always seem to focus on what we don’t know and think that knowing as much as possible is the be all and end all of being a successful vet. Well guys, listen to Professor King. The vast majority of mistakes are down to missing something on physical exam or, for example, failing to realise the significance of an abnormality on blood work or missing something on rads. Put the majority of your effort into SEEING what is there. A B C s You check the ABCs on every case to first make sure that your patient not in (or about to be in) respiratory or cardiorespiratory arrest. Or dead. We’ll cover recognising the arresting patient and cardiopulmonary cerebral resus next week. Major Body System Assessment So the major body systems are the ones that will kill you in minutes rather than hours or days. These are the Cardiovascular, Respiratory and Neurological systems. This week we will talk about the PE parameters we use in our initial MBS assessment. The aim here is to examine the parameters that will give us the most important information as quickly as possible. Over the coming weeks we will cover each system in more detail whereas this week we will focus on what the normal findings are. You have to be able to recognise normal to be able to recognise abnormal. Cardiovascular So for cardiovascular we want to examine the pulses, mucous membranes, capillary refill time, heart rate and have a listen to the heart sounds. Respiratory For respiratory the list is respiratory rate, effort and auscultation Neurological For Neuro, at first, we only want to note whether the animal can walk and walk normally and whether it has normal or abnormal mentation. More importantly, we want to assess whether the gait and mentation are what we would expect to find given the abnormalities we have found for cardiovascular and respiratory. Major Body System Assessment Once we have done cardiovascular, respiratory and neuro, that means that we have done chest and head. Where is the next place that something nasty might be hiding? Abdomen. So if the animal is stable enough we then palpate the abdomen. And again, if the animal is sufficiently stable we should get a body temperature. Don’t forget to always get a temp if you’ve got a dog with an upper airway obstruction. They can have hyperthermia that is high enough to cause heatstroke. Major Body System Assessment So there’s our complete list then. Pulses, Mucous membranes, Capillary refill time, Heart rate, Cardiac auscultation, Respiratory rate, effort and auscultation, Gait, Mentation, Abdominal palpation and Body temperature. Memorise it and make sure that you do them all in every animal unless they are so unstable that you can only do a couple at a time (eg some dyspnoeic cats). Don’t forget to do them all when you find a big abnormality (eg forgetting the CV stuff when you heard crackles in the lungs). And don’t be put off doing them all when you have nasty grossness (!) such as after big ass trauma or abdominal wound dehiscence. Cardiovascular System Hokay, now to consider each body system in a bit more detail. A very important concept here is to always cross reference your findings. Is the heart rate what you would expect given the other parameters? If a cat is in hypovolaemic shock as evidenced by very pale mucous membranes, an absent CRT and very weak femoral pulses, its heart rate should be 220 plus. If it is only 100 why does is have an inappropriately slow heart rate? Could it, for example, be a blocked cat with hyperkalaemia which is slowing the heart rate? Mucous Membranes What is the mucous membrane colour and what is the CRT and does it fill promptly and vigorously? The CRT is an excellent and objective indicator of perfusion status (it’ blood supply is the same as the brain!). Many books will tell you that a normal CRT is 1-2 seconds. I beg to differ! Most dogs in an emergency clinic will have a CRT or 1 to 1½ seconds. 2 seconds is too long. Also remember that fast (<1 second) is abnormal too. You should also note the vigour with which it fills: is it normal, reduced or increased? And lastly, remember that normal cats have paler mms than dogs and that some normal dogs have redder mms than others (eg liver Dobeys or staffy/pit bulls). This video is of a 100% normal dog. What do you think of his CRT? Pulse Evaluation Feeling pulses is one of the most important skills for an emergency clinician. You should always feel both the femoral pulse and the metatarsal pulse. Metatarsal pulses are easier to find than femorals once you have had a bit of practice. As the metatarsal pulses is lost before the femoral with worsening peripheral perfusion yu can use them together to grade the severity of hypoperfusion. (Check out the hairstyle and lovely gold necklace on that emergency doc, err me!;-) Metatarsal Artery The metatarsal pulse is also useful when other factors make the femoral pulse difficult to feel (as with fractures in that area) or if the dog is looking at you like the dog above! I would be a bit hesitant to stick my hand in his groin! Metatarsal Artery In some animals their conformation makes femoral pulse palpation difficult. Obesity is one (this cat weighed just under 20kg: I kid you not!) Some dogs with muscley thighs can also make feeling the femoral pulses difficult. I find Jack Russell femoral pulses particularly challenging. That’s my dog Ronnie when he was a pup. Aaah, isn’t he cute! Pulse Evaluation IMPORTANT! Always assess both the height (strength) and the width (duration) of the pulse. This is what I like to call the pulse profile. This will allow you to estimate the pulse volume which mirrors the stroke volume (the volume of blood pumped by the heart per beat). Take the pulse rate and check whether the pulses are regular or irregular (regularly irregular or irregularly irregular)? Are there early or late ones or irregular gaps? You can get good enough to feel the pulse profile in cats but it takes a LOT of practice. Heart Rate So what is a normal heart rate? Some books say 60-160 for a dog. What a load of rubbish! In an emergency clinic, canine heart rates should be 80-120 and felines, 160-220. By the way, those are not the resting heart rates for a cat, they are the rates you will get in your clinic when they are already tachycardic. If the heart rate is abnormal is it mild moderate or severe and does it match the other perfusion parameters? Respiratory System Respiratory rate and effort are pretty much performed as soon as you see the animal. We’ll cover this in more detail in the respiratory weeks. We’re going to cross reference here in a couple of ways. First, look at the animal’s head and see whether its distress matches the movement of the chest. If its chest tells you that there’s a lot of effort but its head tells you that the animal is not too bothered then a chronic condition is more likely. You should also work out whether the lung sounds match the rate and effort. If it is moving more air, there should be more sounds unless there is something else going on. And lastly, it is absolutley paramount that you remember how unstable dyspnoeic animals can be so you don’t end up having to make... the dreaded phone call... The dreaded phone call! The dreaded phone call! Normal Respiration I count anything over 25 breaths a minute as tachypnoea but consider that 25-30 may be high normal. This way I don’t miss a mild tachypnoea. Because the majority of a resting inspiration is due to diaphragmatic contraction you should not see much chest movement in a dog or cat breathing normally. When the diaphragm contracts it pushes on the abdominal viscera and pushes the abdominal wall out. Consequently, on inspiration the CHEST AND ABDOMEN MOVE OUT TOGETHER. Normal Respiration When you watch the animal’s breathing try to identify inspiration, expiration and the pause between. Count In, Out, In, Out to yourself as you watch. A normal animal should spend just slightly longer on inspiration than expiration. When you have identified the phases, you can then try to see how each phase differs from normal. Here’s my cat Charlie at rest and breathing normally. The first thing you might notice unless you are experienced at evaluating respiratory patterns is that observing the phases of respiration is a little more difficult than you expect. Much of the movement you see on inspiration is abdominal and there is very little chest movement. Normal Respiration And don’t be fooled by purring! This cat is a normal blood donor and you can be forgiven for thinking that he has increased effort. Well he does. Kind of. But if you cross reference with his head you can see that he is a very happy chappy. It’s because he is purring. Pulmonary Auscultation and Lung Sounds This is one of the true arts of veterinary medicine and one you should aspire to excel at as an emergency clinician! You should divide the chest up into cranial, middle and caudal, and dorsal, middle and ventral and auscult each area. Lung sounds should be louder in the cranioventral portion of the chest and symmetrical from left to right. Ignore the heart when you are listening to the lungs and vice versa. If the animal is taking deeper breaths than normal then lung sounds should be louder than normal. So your job is to work out are the lung sounds the correct volume for the tidal volume and effort. An animal that is tachypnoeic from pain, stress or exercise should have louder lung sounds than at rest. Lung sounds Let me explain why lung sounds are louder in the cranioventral chest. Lung sounds are caused by turbulence in the major airways. This is a lateral chest radiograph from a dog with alveolar disease in its left middle lung lobe but don’t worry about the abnormalities for the time being. Can you see the mainstem bronchi to the cranial, middle and caudal lung lobes? I’ve marked them for you in the next slide. Lung Sounds You can see that there are 2 mainstem bronchi in the cranioventral portion of the chest and only one in the dorsocaudal portion. The cranioventral chest is narrower than the dorsocaudal chest. So there are more “noise generating structures” in the cranioventral chest and they are nearer to the chest wall. Et voila! Louder lung sounds! If an animal is taking very shallow breaths then you may not actually hear lung sounds in the dorsocaudal chest. And good luck with purring cats! Neurological System For neuro at this stage we are just interested in the two biggies: gait and mentation and whether they are appropriate for your other findings. Watch this video of a dog that has been shot through the axilla and is in severe hypovolaemic shock. You can see that he has VERY pale mucous membranes and a weak to absent CRT. Just about as bad as it gets! His mentation is depressed or even stuporous (rousable by only painful stimuli). But this is APPROPRIATE given that he is in severe hypovolaemic shock. The other part of your initial neuro evaluation is to see whether there are any signs that may be associated with a horrible prognosis... Hopeless Prognosis This dog has had severe head trauma. The caudal skull is completely smashed... Note that the forelimbs are extended and the hindlimbs are flexed. This posture is decerebellate rigidity and you see it with severe cerebellar injury. If all four limbs were extended in this dog then that would be decerebrate rigidity. Both are grave to hopeless signs in trauma patients. There are also some breathing patterns that are associated with brain injury that we’ll cover later in the course. Simple rule of thumb: if you can recognise an abnormal breathing pattern in a head trauma case then the prognosis is grave! Grave/Hopeless Prognosis The is a hit by car Pit Bull with stiff front legs and normal to flaccid hindlimbs. You can see that he is still conscious and aware. He also has no deep pain in his hindlimbs and a palpable deformity of the thoracic spine. This is Schiff Sherrington Syndrome and in a trauma case usually means functional or absolute cord transection. Major bonus points to anyone who can spot another neurological syndrome in this dog (cos it’s very difficult to appreciate in this picture). Major Body System Assessment So there we have it. Major body system assessment. You should do it automatically and it should only takes a minute or 2. That way you will immediately be able to identify life threatening problems and institute stabilisation measures, then hopefully diagnostic procedures, treatment and cure for your patients... Oh wait! That’s the rest of the course! ;-) You really do see some truly amazing things as emergencies don’t you? I’ll leave you with the following one. “It just came up over night...” Surprise! !!!!!!!!!!!!!!!! Bigger Suprise! And post op! Well I trust you’ve all enjoyed our first Big Picture. Here’s to having a great time with our Emergency Medicine course and I hope you all find learning about emergency medicine as fun and rewarding as I do!