Tag: ABG

Shortness of breath and oxygen

Shortness of breath and oxygen

Sam discusses shortness of breath and oxygen use with Respiratory and General Medicine advanced trainee Dr Cam Sullivan. We also delve into more advanced pneumonia management and investigation as well general expectations of house officers on ward calls.

Differential (acute dyspnoea)

  • Life threatening
    • PE
    • Infection
    • Asthma
    • Anaphylaxis
    • Pneumothorax
    • Pulmonary oedema
    • Pulmonary haemorrhage (TB or anti-coagulated)
    • Anaemia
    • Narcosis
  • Obstruction
    • Chronic/COPD
    • Foreign body
  • Atelectasis – especially post-op
  • Pleural effusion
  • Cardiac
    • Heart failure
    • Arrhythmia
    • ACS
  • Mechanical
    • Obesity
    • Sleep apnoea
    • Flail chest
    • Blocked chest drain
    • Ascites
  • Drugs
  • Pregnancy

Approach

  • Eyeball the patient
  • ABCs – respiratory arrest code if the patient is having difficulty talking to you
  • History
    • Onset
    • Previous shortness of breath
    • Cough/sputum
    • Inhaler use
    • Foreign body
    • Recent new medications
    • Rash/oedema
    • Pain
    • Review of systems
  • Identify risk factors/respiratory background
  • Vitals + Examination
    • General inspection
    • Current oxygen flow rate/FiO2
    • Talking in sentences, broken sentences, single words
    • Peripheries/fluid review
    • Chest wall movements and auscultation
    • Listen to the posterior chest!
    • Listen to the entire breath cycle
    • Heart sounds
    • Abdomen
    • Calf tenderness and swelling
      • Not sensitive or specific. No negative predictive value
    • Chest drain – is it swinging?
  • Investigations
    • ABG
    • ECG
    • CXR – consider urgent/portable
    • Consider FBC, U&E, CRP
    • Pneumonia microbiology
      • Sputum sample
        • Consider adding on atypical panel
      • Urinary antigens
      • Respiratory panel
    • Consider D-dimer
  • Management
    • Posture!!!
    • Chest physio if not clearing secretions (mucous plugging or neuromuscular disease)
    • Analgesia (if splinting)
    • Fluid restriction
    • Frusemide
    • Prednisone
    • Antibiotics
    • Consider discussion with senior and escalation, especially if called back to patient again
    • Consider transfer to respiratory ward
  • Document
    • Review past notes
    • Basics (date/time/name/reason for review)
    • Positives and pertinent negatives
    • Impression and differential with justification. Have you eliminated life threatening conditions?
    • Clear and specific plan
    • Specify target SpO2 range and prescribe oxygen including delivery method.

Oxygen delivery

  • Target SpO2
    • 92 to 96
    • 88 to 92 for CO2 retainer
  • Oxygen delivery methods
    • Nasal canulae
      • 0.5 – 4 L/min
    • Hudson mask
      • 4 – 10 L/min
    • Venturi mask
      • Fixed FiO2 0.21 – ~0.6 (flow rate determined by attachment)
      • Varies from Blue: 24%, White: 28%, Yellow: 35%, Red: 40%, Green: 60%
    • Airvo
      • Fixed FiO2 with PEEP
    • Non-rebreather/reservoir mask
      • High FiO2 >0.9, set to 15 L/min, near 100% as long as reservoir bag does not empty
    • Bag mask
      • Approximate FiO2 1.0
    • BiPAP
    • Invasive ventilation in ICU