The Patient with Undifferentiated Shock

The patient has some sort of shock state. The examiners have launched you at it, to work out what is causing it in ten minutes.

One should keep mindful that there are only a few things it could be:

  • Artifactual (measurement error)
  • Hypovolemic (dehydration or haemorrhage)
  • Cardiogenic (pump failure or valve failure, electrolyte disturbance)
  • Obstructive (tension pneumothorax, cardiac tamponade or massive PE)
  • Distributive (sepsis, vasoplegia, anaphylaxis, hypoadrenalism)
  • Neurogenic (loss of sympathetic stimulus, electrolyte disturbance)
  • Cytotoxic (mitochondrial failure, cellular hypoxia due to abnormal oxygen delivery mechanisms eg. carbon monoxide)

Previous hot cases with this sort of theme to them can be found below.

A Structured Approach to the Undifferentiated Shock Hot Case

The standard introduction

  • The examiner will give you a history.

The prelude to the dance

  • Wash hands.
  • Gown and glove.
  • Ask, if relevant:
    • "Can I turn on all the lights?"
    • "Are there any movement restrictions? Can I sit them up, or roll them on their side?"
    • "Is there a language barrier?"
  • Introduce yourself: “Hi Mr or Mrs Bloggs, I’m Dr So-and-so. I’m going to examine you.”

The Monitors

  • Rhythm
  • Rate
  • Morphology: QRS width,
  • MAP and abnormal morphology of the arterial waveform
  • CVP and abnormal morphology of the CVP waveform
  • Ancillary waveforms eg. the PA catheter waveform
  • Oxygen saturation measurement, and the quality of the waveform
  • End-tidal CO2 waveform and level

A pacing box?

  • Pacing mode
  • Set rate

Sensitivity and pacing threshold may not be relevant.

The Ventilator

One can ask the examiners the following questions:

  • How are we oxygenating this patient?
  • How are we ventilating this patient?
 

One should ask about the following parameters:

  • FIO2
  • PEEP
  • Peak pressure
  • Plateau pressure
  • Tidal volume and minute volume

Urine catheter

  • Unusual colour
  • Anuria

Urine output is important. One should ask for the recent trends.

Drains (surgical, intercostal, etc)

There may be surgical drains (what is in them? How much of it?). Asking how much has been coming out may be relevant in a hot case which focuses on the diagnosis of a shock state.

The pleural catheters are also interesting. One should make a mental note of whether the ICCs are on free drainage or on suction. The content of these drains could be informative, especially if one notices blood or chyle.

Dialysis

A CVVHDF or SLEDD process may be in progress. The savvy candidate may wish to ask the following questions:

  • Which modality is being used?
  • What is the dose of dialysis?
  • What is the rate of fluid removal?
  • How is the circuit anticoagulated?
  • How long has this filter lasted?

The patient's shock state may have resulted in multi-organ system failure. One should view CRRT as a marker of severity. It would be worthwhile asking whether they were dialysis dependent before their admission to the ICU.

IABP / ECMO

The patient you are examining may have some sort of extra gadget hooked up. If ECMO is in progress, one may wish to ask about the following parameters:

  • VA or VV?
  • Flow rate
  • Fresh gas flow
  • Any recent problems with the circuit

If IABP counterpulsation is in progress, it almost confirms cardiogenic shock. Nevermind that the patient may not be shocked any more - counterpulsation may have improved the situation - but reliance on 1:1 counterpulsation demonstrates a poor cardiac reserve. One may wish to ask the examiners whether one may be able to switch it to 1:2, to assess the efficacy of augmentation.

Infusions

This stage is critically important. The drug and fluid infusions which are currently in progress give a clue as to what problem is currently being addressed. One should not neglect the labelled bags; the choice of antibiotics gives one some idea of where the source of sepsis is thought to be.

Vasopressors and inotropes are the key features here.

One may also wish to ask whether the patient has received any levosimendan in recent history.

EVD

One should observe the following features of an EVD:

  • Set height
  • Whether it is open or closed
  • The CSF colour - eg. is it full of blood?

The physical examination

Expose and observe

Ideally, one should get the patient sitting up to 30-45°. This may not be possible. However, one should still ask for it.

Ideally, the patient should be exposed from the waist up. The candidate can then stand back and look for anything externally obvious:

  • Skin colour, eg. jaundice or the discolouration of chronic renal failure
  • Muscle wasting, obesity
  • The evidence of trauma, wound dressings, etc
  • The pattern of breathing (eg. whether there is a characteristic chest flail)

GCS

Performing the GCS should be the first step, unless you notice that a neuromuscular junction blocker is among the infusions. The level of consciousness then determines how you go about examining the rest of the patient.

A traditionalist, who is examining Mr Bloggs, would approach the GCS in the following manner:

  • Grab hold of both of the patient's hands.
  • "Mr Bloggs!" One pauses to observe for eye opening.
  • "Can you squeeze my hands?"
  • If hand squeezing and eye opening is not observed, one administers a painful nail bed stimulus to both hands, to observe the response to pain.

Hands, nail signs, pulse and the arterial line.

One has just performed a GCS assessment; one is still holding the hands.

Now, time to look at them more closely.

First, one should spent a second assessing whether they are warm or cold. This is of critical importance in the examination of the shocked patient. The question one answers is "is the peripheral perfusion satisfactory?"

Then, one can focus on the nails. Nail signs are numerous and deserve their own page.

In brief, the nail signs one could look for are as follows:

Done with the nails, one may want to briefly consider (and maybe even comment upon) the presence of any sort of characteristic deformities, eg. assymetrical wasting of the small muscles, or the joint changes of rheumatoid arthritis.

Next comes the pulse. While one still has both of the patient's hands, one ought to try to compare the radial pulses. It would be worthwhile to look up at the arterial line trace at this stage; abnormalities such as the widened pulse pressure of aortic regurgitation may not have been noticed until this stage.

Arms

Tone of the upper limbs

Move up from the hands. While you are still holding the hands, you can perform a sort of gross examination of tone by pronating and supinating the wrists, and by flexing and extending the elbows.

Asterixis

In the conscious patient, it may be possible to assess asterixis by asking the patient to hold both their arms up with the wrists dorsiflexed.

Palpation

Examine the arms:

  • lines
  • evidence of multiple venipunctures
  • lymph nodes
  • brachial pulse
  • AV fistula
  • axillary lymph nodes

Lymph nodes are very important here: they may give one the hint that not all is well with the immune system.

The Neck

Inspect:

  • Lines: CVC, vas cath, PAC

Palpate:

  • Trachea: is it midline? Is there a new tracheostomy there?
  • Thyroid gland
  • Cervical lymph nodes
  • Carotid pulse - one side at a time!
  • Submandibular lymph nodes
  • Pre- and post-auricular lymph nodes

Pupils and the cranial nerves

The cranial nerve exam is probably not going to be of great use in the diagnosis of undifferentiated shock.

One may wish to limit oneself to the following brief review:

The patient may give every sign of being brain dead, in which case one might want to perform some of the cranial nerve tests for brain death. Or they may be a cooled paralysed cardiac arrest survivor, in which case one may have nothing at all to find on neurological examination.

Light reflex

Ask the examiners to dim the room lights.

Open both eyes. Each eye is exposed to light. The opposite pupil should constrict consensually.

This tests CN II (afferent) and CN III (efferent).

Gag reflex

The Yankeur sucker is used to probe the posterior pharynx, on both sides. A gag reaction should result from this.

This collectively tests CN X and IX.

Cough reflex

While on the subject of CN X, one may test the cough reflex by suctioning the trachea.

Airway

During the cranial nerve examination, one will inevitably end up tripping over the endotracheal tube. One should note whether there is anything unusual there; for instance, is there a dual-lumen tube, or a bronchial blocker?

Chest palpation, percussion and auscultation

Palpation:

One puts both their hands on the chest to assess the symmetry of chest expansion.

Percussion:

One might wish to percuss the chest.

Changes in percussion resonance may be worth commenting on.

Auscultation:

One may begin by auscultating the apices anteriorly. Then, one should auscultate as posteriorly as possible. The money is in the bases.

Pulmonary oedema or ARDS will add to the picture of multi-organ system failure.

Palpation and auscultation of the praecordium

Palpation:

The clever candidate will make a big show of palpating both the apex and the right sternal edge.

Auscultation:

One should auscultate in the following sequence:

  • Apex
  • Left sternal edge, lower
  • Left sternal edge, upper
  • Right sternal edge, lower
  • Left sternal edge, upper
  • Both carotids

The various clicks and murmurs one encounters are discussed elsewhere.

Abdominal palpation, percussion and auscultation

For this, one should ask to lay the patient flat.

Abdominal observation

  • Take a moment to behold the abdomen. One may ask the examiners to look under any surgical dressings; one is likely to be denied this part of the examination (they will tell you the wound looks clean and dry).

Abdominal palpation

  • All quadrants should be palpated.
  • Then, feel for the liver edge; observe respiratory excursion
  • Then, feel for the spleen.
  • Then, try to ballot the kidneys. Enquire about renal tenderness.

Abdominal percussion

  • This can double as a test for peritonism.
  • If there is some suspicion of ascites, one may ask to roll the patient, so shifting dullness can be better appreciated. The examiners may not permit this test.

Abdominal auscultation

  • One should spend a good length of time on this, if one suspects bowel obstruction or ileus.

Examination of the pelvis and groins

The pelvic content would have been palpated during the abdominal examination.

The more important part of this examination is the groin.

At this stage, the patient should be re-draped - cover them from the waist up, and uncover their legs.

Observation and palpation of the pelvis:

  • There may be a rash of thrush, or a groin haematoma, or an external fixation device.
  • The posterior pelvis and sacrum should ideally be palpated for pitting oedema.

Examination of the lines

  • One should take notice of anything going into or coming out of the femoral vessels.
  • There may be a vascath, a PiCCO catheter or some sort of angiography sheath. These are important clues. Why did this patient get an angiogram? What is the PiCCO for?

Examination of the genitals and rectum

  • Take note of any sort of waste management devices, eg. rectal tube, SPC or IDC.
  • One should definitely ask about performing a PR
  • If one is forbidden from performing the PR, one should ask about the following features:
    • Anal sphincter tone
    • Size and quality of the prostate
    • Presence of melaena or hard stool

Once one is finished with the pelvis, one should cover it again, so that only the legs are sticking out.

Examination of the lower limbs

One should ask to remove TEDs and compression stockings.

  • One should observe whether the lower limbs are mottled, and whether they are of the same size (assymetrical swelling leads one to suspect lymphoedema or DVT)
  • One should palpate the larger muscles.
  • One should assess the temperature difference between the limbs.
  • Pitting oedema should be palpated.

Calf tenderness

In the conscious patient, one might be able to assess whether a gentle calf squeeze produces the characteristic pain which suggests a DVT may be present.

Feet and the Babinsky reflex

The feet would have already been palpated to assess their temperature, and to look for pitting oedema.

Observation of the feet

One should look specifically for changes suggestive of chronic diabetic foot disease, or chronically poor vascular supply.

Palpation of the feet

This should consist of palpating the dorsalis pedis and posterior tibial pulse.

Babinsky reflex

One should test the Babinsky bilaterally.

Clonus

One should attempt to assess clonus in both feet.

Power in the lower limbs

Testing the limb power in an undifferentiated shock hot case is a matter of excluding central nervous system causes of shock, such as a spinal cord transection or epidural abscess.

Power of the muscle groups may be tested in the following sequence:

  • Ankle dorsi and plantarflexion
  • Knee flexion and extension
  • Hip flexion, extension, adduction and abduction.

Power in the upper limbs

The patient has spent most of this time flat and supine. Time to sit them back up again.

Power of the upper muscle groups may be tested in the following sequence:

  • Hand grip
  • Wrist dorsiflexion/palmarflexion
  • Elbow flexion/extension
  • Shoulder adduction / abduction

The measured observations

Ask to see the obs chart. If it is not allowed, ask for the following:

  • Trends of blood pressure and heart rate
  • Temperature
  • Drain output
  • Urine output

One may also wish do demonstrate an interest in the trends of any sort of advanced haemodynamic monitoring, eg. cardiac index as measured by PAC or PiCCO. If these are present, they offer a handy way to characterise the shock state (eg. the high cardiac output and low peripheral resistance of sepsis).

The laboratory investigations

One needs to show an interest in the following labs:

  • ABG
  • Routine bloods
  • Urinalysis
  • Culture results
  • CK, troponin, LFTs, pancreatic enzymes, inflammatory markers.

Imaging and other investigations

One should always ask for the following:

  • ECG
  • CXR

You sometimes want to see the following:

  • CSF analysis
  • CT or MRI results

 

Case presentation and discussion: when you have a good idea of what is going on

"Mr Bloggs is in a state of [septic, cardiogenic, distributive etc] shock."

"I have come to this conclusion on the basis of the following findings: [insert clinical findings here]"

"I would like to confirm my diagnosis with the following investigations: [insert appropriate investigations]"

"The current management issues are as follows: [a brief list of management priorities]"

"I would approach the management of these issues in the following manner: [list of management strategies; it helps to organise this into an A,B,C,D,E approach if one has a complex multisystem problem to manage]"

Case presentation and discussion: when you don't have a clue

”Mr Bloggs is in a shock state, the cause of which I have thus far been unable to ascertain. This shock state is characterised by the following features: [list features, eg. warm/cool, hyperdynamic circulation, etc]"

"I note that this shock state is complicated by the following organ failures: [list organ problems]."

"I have identified clinical findings which support this hypothesis: namely, [insert list of findings]." "The possible aetiologies responsible for this presentation could include [list of differentials]"

"In order to discriminate between these differentials, I would like to perform the following investigations: [list of investigations]"

"Furthermore, I would like to enlist the help of the following specialties [insert list of consults], for whom I will have the following specific requests/questions: [what questions will you ask these specialist teams]"

"In the meantime, my management would consist of the following supportive strategies: [outline approach to haemodynamic support and management]"

Number of previous hot cases in this topic: 4

2015, Paper 2

Unspecified hospital in Adelaide

43-year-old male, admitted to ICU one week earlier with septic shock and respiratory failure, intubated 2 days later and developed seizures. Background included active IV drug use. Clinical findings included sedated and intubated, splinter haemorrhages, Janeway lesions, injection sites in the groin and mitral regurgitant murmur.

Candidates were directed to examine him to determine the cause of his septic shock. Discussion points included antibiotic therapy, contra-indications to surgery and prognosis.

2014, paper 2

Unspecified hospital in Sydney

  • 56 year-old-man, day 4 ICU. Background of MI three weeks previously, followed by respiratory failure of uncertain aetiology with bilateral lung infiltrates, normal cardiac output and low filling pressures. Clinical findings included bilateral fine crepitations, evidence of airflow obstruction, and a vasodilated state.
  • Candidates were informed that the patient had respiratory failure and shock following a recent MI. They were asked to examine him to find a likely cause.
2014, Paper 1

Princess Alexandra Hospital

  • 67-year-old male, day 2 ICU post elective low anterior resection.Clinical findings included obesity, haemodynamic instability with high dose inotropic support, atrial fibrillation, aortic stenosis and low urine output, bibasal collapse and a fresh midline incision with a viable stoma.
  • Candidates were directed to examine him and determine the cause for his haemodynamic instability and failure to wean.
2013, Paper 1

Flinders Medical Centre

  • 73-year-old man, day 3 In ICU with septic shock and severe respiratory failure on a background of urosepsis (previous nephrectomy) and left ventricular failure. Candidates were asked to perform a general examination and present a differential diagnosis.