FRCA Notes

Upper Respiratory Tract Infection

This topic has its own bespoke curriculum item: 'Explains the importance of identifying when upper respiratory tract infections are/are not significant and, as a result, when to cancel operations'.

It was the subject of an SAQ in 2017, with marks for clinical features increasing risk of airway complications, reasons why it would be inappropriate to cancel the operation and social factors precluding day surgery.

Resources

  • Upper respiratory tract infection is the commonest reason for children to visit the emergency department or outpatient clinic
  • Most children can expect to have 6 - 8 URTIs/year
  • 95% are viral in origin
    • 30-40% of viral cases are due to rhinovirus, although over two hundred viruses cause URTIs
  • The quintessential issue is the tendency to bronchoconstriction, arising via multiple mechanisms:
  1. Release of inflammatory mediators at sites of viral damage
    • Bradykinin, prostaglandin, histamine and interleukin

  2. Viral neuraminidases inhibit M2 muscarinic AChR on vagal nerve endings
    • Atropine has been shown to block airway hyperreactivity, which supports vagal involvement

  3. Viral inhibition of endopeptidase, which normally inactivates tachykinins
    • Leads to increased smooth muscle constrictor response to tachykinins

  • Rhinorrhoea (66%)
  • Nasal congestion (37%)
  • Sneezing (29%)
  • Cough (26%)
  • Sore throat (8%)
  • Fever (8%)
  • Constitutional symptoms such as irritable behaviour, malaise

Differential diagnosis


Infectious Non-infectious
Croup Asthma
Bronchiolitis Allergic rhinitis
Influezna Inhaled foreign body
Streptococcal laryngitis Hypertrophic adenoids
Pneumonia GORD
Epiglottitis
Herpes simplex


  • A history of URTI increases the risk of adverse events such as:
Airway events Breathing events
Laryngospasm (~3x risk) Bronchospasm (~3x risk)
Breath-holding Hypoxia (SpO2<90%)
Post-extubation stridor Atelectasis
Need for unanticipated tracheal intubation or re-intubation Coughing
Airway obstruction Pneumonia
  • The risk of such complications is highest during the acute infection, but remains for 2-6 weeks post-resolution of symptoms
  • Airway hyper-reactivity remains for 6-8 weeks post-URTI
  • Most complications are readily manageable and short-lived

Patient factors

  • Prematurity (<37 weeks)
  • Age <6yrs (and even moreso <1yrs)
  • History of asthma or atopy
  • Existing airway anomaly
  • Parent confirmation 'my child has a cold'
  • Family member who smokes

  • Symptoms
    • Snoring
    • Nasal congestion
    • Presence of copious secretions
    • Purulent discharge
    • Dyspnoea

Anaesthetic factors

  • Induction agent
    • Thiopentone carries highest risk
    • Inhalational induction intermediate
    • Propofol lowest risk

  • Maintenance agent
    • Conversely, TIVA carries a higher risk than volatile maintenance

  • Junior anaesthetist
  • Inadequate reversal of NMBA

Surgical factors

  • Major surgery
  • Airway surgery, whether major or minor
  • Surgery necessitating intubation

  • Various flowcharts exist to decide whether to proceed or cancel
  • One such method is to categorise the URTI as 'mild', 'moderate' or 'severe'
  1. Mild URTI: recent URTI but appears healthy and has had no acute signs or symptoms in the past 2-4weeks

  2. Moderate URTI: clear rhinorrhoea and dry cough, but clear auscultation, no fever or irritability for >2days

  3. Severe URTI: fever >38°C, purulent nasal discharge, productive cough, looks unwell and/or signs of pulmonary involvement
  • Investigations
    • CXR, FBC or nasopharyngeal swabs are seldom necessary
    • They are not cost-effective and may be impractical
    • They may be considered if a diagnosis of LRTI is suspected instead

  • Those with mild URTI can often be safely anaesthetised without significant morbidity
  • Those with moderate URTI will need a risk/benefit decision in conjunction with the parents and surgeon
  • Those with severe symptoms should have elective surgery postponed for at least 4 weeks

Postponing surgery

  • It is not practical to 'blanket' cancel all patients with URTIs
  • Postponing or cancelling surgery may increase the emotional and economic burdens on parents
  • It may also cause harm if there is a risk associated with delay e.g. for grommet insertion there may be long-term hearing impairement if otological issues not treated
  • Assessment of the suitability of proceeding should depend on:
    • Child's age and current clinical status
    • Severity of URTI (see above)
    • Presence of comorbidities
    • Urgency and type of procedure
    • Frequency of URTI's; may be difficult to schedule a child during a symptom-free interval if frequent

Perioperative management of the child with a recent URTI


  • Ensure anaesthetist of adequate experience is present

  • Pre-medication with anticholinergics does not confer benefit vs. placebo and should not routinely be used
  • α2-adrenergic agonists are better than benzodiazepines if anxiolytic premedication is indicated

  • Give bronchodilators 10-30 minutes prior to surgery e.g. β2 agonist such as salbutamol combined with inhaled corticosteroid
    • 2.5mg salbutamol if weight <20kg
    • 5mg if weight >20kg
  • Keep well hydrated e.g. sip 'til send

  • Naturally, the goal is to avoid or limit stimulation of the potentially irritable airway

Anaesthetic technique

  • Use IV propofol induction, or inhalational if IV access unobtainable
  • Consider IV lidocaine to suppress cough reflex

  • Avoid intubation if possible, particularly if <5yrs old
  • Consider lubricating the LMA with lidocaine gel (although some studies suggest no benefit from topical lidocaine)

  • Maintain anaesthesia with volatile, sevoflurane rather than desflurane
  • Use lung protective ventilation strategies

  • Only suction under deep anaesthesia
  • Use humidified oxygen

  • Multi-modal opioid-sparing analgesia including regional anaesthesia
  • Suction under deep anaesthesia
  • Extubate awake
  • Consider 1.5mg/kg lidocaine IV 2mins prior to extubation, which may reduce incidence of post-extubation laryngospasm and coughing
  • Humidified supplemental oxygen
  • Meticulous post-operative respiratory monitoring