Category: Respiratory

COVID-19 (40 Step Desaturation Test)

NHS England has introduced the use of a “40 step desaturation test” into discharge planning from the ED. You will have heard Covid -19 patients complaining of increasing SOB on exercise, and it’s important that we test this prior to discharge.

Method:

  • Is this appropriate? – Could the patient walk 40 steps before they were ill?
  • Patient remains in cubical – with mask on
  • Attach Sats probe – ensure good trace
  • Walk on spot 40 steps 
  • Monitor SaO2

 

 

COVID-19 (Awake Self-Proning)

There is increasing evidence that Awake Self-Proning of our Covid-19 patients can improve oxygenation. Proning the patient can has several effects which can dramatically improve their SaO2

  • Improves Ventilation to back of the lung (the back of the lung contains more alveoli than the anterior lung)
  • Improves Perfusion – as blood supply to the back of the lung is always better than the front
  • Improves Clearance of secretions
  • Be patient can take 15-20min

Contraindications (all seem obvious)

Absolute contraindications:

  • Respiratory distress (RR ≥ 35, PaCO2 ≥ 6.5, accessory muscle use) 
  • Immediate need for intubation 
  • Haemodynamic instability (SBP < 90mmHg) or arrhythmia 
  • Agitation or altered mental status 
  • Unstable spine/thoracic injury/recent abdominal surgery 

Relative Contraindications: 

  • Facial injury 
  • Neurological issues (e.g. frequent seizures) 
  • Morbid obesity 
  • Pregnancy (2/3rd trimesters) 
  • Pressure sores / ulcers 

 

COVID-19 (X-Ray learning resource)

British Society of Thoracic Imaging (BSTI) have released a free learning resource containing CXR and CT of confirmed Covid-19 cases, will short history including time image was taken from onset of symptoms.

From the China experience CXR/CT doesn’t seem to be a rule out strategy in ED at the moment – However, its a useful resource to help recognition of Covid-19 CXR’s

BSTI Covid-19 image bank

 

Acidosis & VBG’s

We are frequently asked to check the lactate on Venous Blood Gases (VBG’s), by the nursing staff. However, remember to look at the first result (pH) it is the most important.

Acidosis: Unless you have a good reason (e.g. you know its due to DKA) you should be investigating and performing an Arterial Blood Gas (ABG)

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A-a gradient

A-a gradient = Alveolar Oxygen – arterial Oxygen

This is “relatively” simple way of working out if the paO2 on a ABG is normal, and demonstrates V/Q mismatch well. V/Q mismatch is simple terms is either an area of the lung either under ventilated(pneumonia) or under perfused (PE). Read more

COPD think VBG

Why VBG instead of ABG?

  • Pain – we all know and warn our patients ABG’s are painful. Patients know it to and delay presentation.
  • Number of bloods taken – patients attending with COPD will generally have venous bloods taken at triage. Would you want stabbing again if it could be avoided?

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