Why does this patient have respiratory failure?

The problem could be at any level:

• Central (hyper or hypoventilation)
• Cranial nerve (aspiration, or poor cough)
• Neuromuscular junction (weakness, poor cough)
• Pleural disease (pneumothorax, plaques)
• Airway disease (bronchospasm or bronchiectasis)
• Parenchymal disease (pneumonia, emphysema, fibrosis, ARDS)
• Chest wall abnormality (eg. kyphosis/scoliosis, or flail chest)
• Abdominal abnormality (eg. distension, post-operative pain)
• Cardiac failure (decreased tolerance of respiratory effort, or increased lung parenchymal fluid resulting in decreased compliance)

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

A Structured Approach to the Respiratory Failure Hot Case

The standard introduction Listen to the introductory statement. Wash hands; don gloves and gown. A mask may be required Ask examiners about turning up the lights   The environment Monitoring (SaO2, EtCO2) Ventilator (MOST IMPORTANT!) Urine catheter Drains (especially intercostal) Dialysis IABP / ECMO Infusions EVD Weird machinery   The physical examination The details of this section can be seen in the opposite column.   The obs and investigations Temperature, urinalysis, drain output, urine output Specialised respiratory tests ABG, ECG, bloods, culture results CXR, CT images and CSF analysis. The Presentation "I know the diagnosis" "I have no idea what is going on"

The Physical Examination in Brief Detail Ask the examiners to sit the patient up Expose to the waist and observe. Ask the examiners about any language barriers GCS Hands, the nail signs, pulse and arterial line Arm tone and upper limb lymph nodes Neck lymph nodes, trachea, thyroid A limited cranial nerve exam: Horner's syndrome Gag reflex Cough reflex Tongue movements Uvula deviation Ask about the sputum Chest palpation, percussion, auscultation, and ask to roll over Praecordium palpation, auscultation, and ask for Valsalva Ask examiners to lay the patient flat. Abdominal palpation, percussion, auscultation Pelvis: groins, lines, and ask about performing a PR Legs: oedema and calf compressors. Leg muscle tone. Feet and Babinsky; clonus. Dorsi/plantarflexion power, knee and hip power Sit the patient back up again Hand, wrist, biceps, shoulder and shrug power Reflex testing, in hand-to-foot order Sensory testing, 13 points in foot-to-hand order Cerebellar exam of upper limbs and torso

The standard introduction

• The examiner will give you a history.

The prelude to the dance

• Wash hands. Failure to do this identifies the candidate as an unhygienic oaf.
• 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 your (insert system here).”
  This routine behaviour gives you a moment to compose yourself, and prepare to launch into your smoothly polished well-practiced examination technique.

One should point out before going any further that the patient being examined may be prone. This is an entirely different kettle of fish, and calls for a different approach.

The Monitors

• SpO₂ is important.
• The EtCO₂ waveform can also yield interesting information.
• The respiratory change in arterial pulse amplitude may be a sign of dynamic hyperinflation

The routine is also relevant.

• 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

The Ventilator

• This is probably the most important part of the end-of-bedogram.
• Careful scrutiny of the settings is expected.
• Specific features one should focus on:
  • How are we oxygenating this patient?
  • How are we ventilating this patient?
  • What is the effect of the settings (i.e. is everything still crap in spite of our efforts?)
  • One may ask to perform an inspiratory hold. If this is not permitted, one should ask about the following parameters:
    • FIO₂
    • PEEP
    • Peak pressure
    • Plateau pressure
    • Tidal volume and minute volume

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

Urine catheter

• Unusual colour
• Anuria

Drains (surgical, intercostal, etc)

Special attention should be paid to the behaviour of the ICCs.

If there is a constant vigorous air leak, one should prepare for a vigorous discussion of bronchopleural fistula.

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?

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

The presence of extracorporeal circuits may act as a marker of severity. One must have failed conventional ventilation to move on to ECMO.

If IABP counterpulsation is in progress, it raises additional questions. 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

• Specifically, one needs to keep mindful of brochodilator infusions.
• The patient may be paralysed.
• There may be antibiotics hanging.
• A bottle of IV immunoglobulin may be left for the candidate to find, a clue to a vasculitic cause of respiratory failure.

EVD

Intracranial pressure monitoring may point to the central nervous system as a cause of the respiratory failure. Has the patient lost their medulla? Or have they had severe neurogenic pulmonary oedema following an SAH?

Weird machinery

The respiratory failure patient may have a plethora of additional devices around them. These may include the following:

• Heliox
• NAVA
• Prostacycline nebuliser
• INOmax or another nitric oxid gas blender

The presence of such toys is a splendid gift, as it all but delivers the case into the hands of the candidate.

---

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.

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)
• Assymetry of chest wall movement (eg. a pneumonectomy)
• Chest wounds or old scars

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 whther 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:

A candidate examining the respiratory failure patient needs to dwell on the clubbed digits. The examiners must appreciate the fact that clubbing has been found, and that the candidate is very excited about it.

Then, one should note the presence of any sort of characteristic deformities, eg:

• Assymetrical wasting of the small muscles
• Joint changes of rheumatoid arthritis
• Hypertrophic pulmonary osteoarthropathy

Next comes the pulse.

• Compare the radial pulses.
• Observe the arterial line trace again.

Arms

Tone of the upper limbs

Perform a gross examination of tone by pronating and supinating the wrists, and by flexing and extending the elbows. This is not the primary focus of the respiratory failure examination, but one should keep in mind that the respiratory failure may be due to some sort of myopathy or neuromuscular disorder, which may reflect in a decreased tone.

Asterixis

In the consciosu patient, it may be possible to assess asterixis by asking the patient to hold both their arms up with the wrists dorsiflexed. This may be useful if hypercapnea is suspected.

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:

• 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 higher cranial nerves

A sophisticated and detailed cranial nerve examination is desirable; however, the limitations of the respiratory failure hot case force one to truncate this part of the examination.

Thus, after looking for Horner's syndrome in the eyes, one should focus on the lower cranial nerves (those involved with speech and swallowing):

• Horner's syndrome
• Gag reflex

• Cough reflex
• Tongue movements
• Uvula deviation

Horner's sign

This sign, associated with stroke and with an apical lung tumour, is composed of the following features:

• Ptosis
• Miosis (narrowed pupils)
• Anhydrosis
• Enophthalmos
• Bloodshot conjunctiva

It is a classical med-school sign. If it is present, and you miss it, your examiners will be very disappointed.

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.

This tests CN X.

This is also a convenient time to ask about the volume and character of the secretions.

Tongue movements

The conscious patient is asked to protrude their tongue, and move it from side to side.

This tests CN XII.

Uvula deviation

The uvula deviates away from the lesion.

This tests CN X and IX.

The airway is worth spending some time on.

Specific clues will be grossly obvious: eg. the dual lumen tube with one lumen clamped, or the endobronchial blocker, or the flanged tracheostomy tube.

It would also be worthwhile to note whether the cuff pilot balloon is well inflated. A tracheostomy patient with the cuff deflated may be able to speak, and is likely ready for decannulation.

Important questions to ask at this stage would be the character and quantity of secretions, and how long the patient has been intubated.

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.

Not everybody does this in their day-to-day practice, and in hot case practice scenarios consultants who are not college examiners tend to either scoff at this practice, or attribute to it an undue emphasis. Theoretically, percussion is a part of the physical examination and should not be forgotten, but it is a low-yield investigation and one may wish to omit it if one were asked to focus on another system.

Auscultation:

One may begin by auscultating the apices anteriorly. Then, one should auscultate as posteriorly as possible.

The money is in the bases.

This, if done thoroughly in a patient on a mandatory mode, may be somewhat laborious (there may only be 12 breaths per minute, and one needs a breath for every change in stethoscope bell position).

Palpation and auscultation of the praecordium

The cardiac examination is a part of the respiratory assessment.

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.
• The specific things one is looking for is distension and abdominal wounds; these findings may suggest that the diaphragmatic excusion is impaired.

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 exmaination. 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

• One should take note of any 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 (assymmetrical 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; it may be reflective of a systemic weakness, which may contribute to respiratory failure.
• Pitting oedema should be palpated.
• Test the tone of the leg muscles.
• Look for calf tenderness.

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

Now is the time to properly start the neurological examination of this patient.

In the context of the respiratory failure hot case, one is looking for the following features:

• Asymmetry of power, suggestive of stroke
• Generalised decrease, suggestive of global weakness
• Proximal power loss, suggestive of myopathy

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

Specialised respiratory investigations

One may wish to ask for the following information:

• Spirometry
• Peak expiratory flow
• Maximum inspiratory and expiratory pressure (MIPs and MEPs)

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

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' respiratory failure is multifactorial."

"Contributing factors include [insert a list of respiration-impairing aetiologies]."

"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 this respiratory failure 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]"

"My approach to ventilation in this setting would consist of the following strategies:[describe how you would change the ventilator settings]"

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

”This is a complex case and I’m not certain of the diagnosis."

"I note the following organ dysfunctions which may be contributing to the respiratory failure: [list contributing organ problems]."

"I have identified clinical findings which support this hypothesis: namely, [insert list of findings]." "Thus, the possible aetiologies responsible for this respiratory failure 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 absence of a clear diagnosis, my ventlation strategy would consist of the following techniques: [demonstrate to the examiners that you would be able to ventilate this patient safely in the absence of a clear diagnosis]"