The Prone-Ventilated Patient

One does not prone lightly. Something terrible has happened in the lungs. Potential aetiologies include:

  • Severe ARDS
  • Large-scale aspiration pneumonia
  • Massive haemoptysis or alveolar haemorrhage

The main issues to focus on:

  • Management of severe hypoxic respiratory failure
  • Management of complications arising from the prone position

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

Examination of the Patient being Ventilated in the Prone Position

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?"
    • "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

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

One should ask to look at the pressure-volume loops.

This patient has severe rspiratory failure, and it would be worthwhile dedicating a little time to the ventilator.

If a prostacycline nebuliser is present, one should make a note of it.

Urine catheter

  • Unusual colour
  • Anuria

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?

These questions may go unanswered.

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.


The physical examination

Expose and observe

Ideally, one should get the patient sitting up to 30-45°, but the patient is prone, so that won't happen. Also pointless is to ask the examiners whether it woud be possible to turn them supine (the answer is no).

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.

GCS

Performing the GCS should be the first step, but the patient is likely either heavily sedated or paralysed, and probably both.

If the patient is paralysed, one should ask about the train of four.

If the patient is merely sedated, one may attempt to ascertain a GCS.

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.

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.

Pressure areas

  • Prone positioning exposes one to pressure areas around the medial epicondyles of the humeris, and the head of humeris.One should make a performance of examining for these.

Cubital fossa

Examine the cubital fossa for

  • Peripheral lines
  • Evidence of multiple venepunctures
  • Lymph nodes
  • Brachial pulse
  • The presence of an obvious AV fistula

One should then palpate the axillary lymph nodes.

The Neck

  • Inspect any central lines
  • Look again at the CVP

Palpate the neck, if one is able.

In order to do this, one may ask for some help holding the ETT, as it could be dislodged by the process.

The examiners will probably deny you this opportunity.

If one is able to get to the neck one should look for the following answers:

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

Facial pressure areas

The examination of the face and head is not going to be possible in any conventional sense.

Instead, one could ask to examine the face for the follwoing pressure areas:

  • Eyes
  • Bridge of nose
  • Mentum of chin
  • Periorbital skin

Ask about tongue oedema.

Observe the feeding tubes.

Ask about NG aspirates and feed tolerance.

Airway and the secretions

One should ask about the volume and character of the secretions.

One should also ask for permission to suction the trachea, so one might see them.

Chest palpation, percussion and auscultation

Palpation:

One puts both their hands on the chest to assess the symmetry of chest expansion. One only has the back to play with, but this may be enough.

Percussion:

One might wish to percuss the back. This is the perfect opportunity to do so.

Changes in percussion resonance may be worth commenting on.

Auscultation:

One may begin by auscultating the back, moving as far anteriorly as positioning will allow.

One should ask whether there are breast implants, and comment that they pose a pressure area risk.

Palpation and auscultation of the praecordium

Usually, the praecordium cannot be assessed.

  • The patient will not be flipped over to help your examination.
  • However, one may be able to sneak the stethoscope under the patient to palpate and auscultate the apex.
  • One should still listen to both carotids

The various clicks and murmurs one encounters are discussed elsewhere.

Abdominal palpation, percussion and auscultation

Again, this is going to be impossible.

One may be able to reach around the flanks of a thin patient and palpate some of the abdomen, but this may not yield anything of use.

If there was an intraabdominal catastrophe, the patient would not have been proned.

Examination of the pelvis and groins

The pelvis also cannot be assessed fully. At this stage, the patient should be re-draped - cover them from the waist up, and uncover their legs. The groins may not be accessible.

Observation and palpation of the pelvis:

  • The anterior pelvis and sacrum should ideally be palpated for pitting oedema.
  • One should examine the anterior superior iliac spines for pressure areas.

Examination of the lines

  • One should take notice of anything going into or coming out of the femoral vessels. However, one will probably not be able to see the insertion sites (but one should ask to look at them anyway).

Examination of the genitals and rectum

  • A complete examination would call for the palpation of the testes, and a comment on their size. However, this may not be practical.
  • One should 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

It is important to ensure that the examiners are aware for your concern of pressure area risk to the male genitalia.

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. Muscle wasting - especially of the quads- is an important feature of malnutrition. Additionally, one gets to appreciate the temperature difference between the limbs, which could be important in the assessment of peripheral vascular disease.
  • Pitting oedema should be palpated.

Leg muscle tone

The best way to test muscle tone in this position is to hold the leg by the foot, and gently flex and extend the knee. However, this may all be useless, as the patient may be paralysed.

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.

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

The laboratory investigations

One needs to show an interest in the following labs:

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

Imaging and other investigations

One should always ask for the following:

  • ECG
  • CXR
  • CT or MRI results

 

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

"Mr Bloggs is suffering from severe respiratory failure[insert clever diagnosis here]."

"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]"

"Additionally, prone ventilation in this case has been [well managed / complicated by the following problems]"

"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]"

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