FRCA Notes

Post-Operative Care Following Thoracic Surgery

The curriculum asks for knowledge of 'the common problems associated with the postoperative care of patients who have had thoracic surgery and the methods that can be used to minimise these'.

Resources

  • Even in patients without underlying lung disease, the incidence of post-operative pulmonary complications following thoracic surgery is 5 - 10%
    • It is significantly higher in those with pre-existing lung disease
    • Optimising certain aspects of post-operative management can influence the frequency and severity of these complications

Ventilation

  • Extubate immediately or as soon as possible
    • Reduces risk of acute lung injury, VAP, bronchial stump disruption, bronchopleural fistula and persistent air leak
    • Facilitates early recovery by allowing initiation of rehabilitation and resumption of oral intake

  • Predictors of requiring prolonged ventilation:
    • Need for intra-operative blood transfusion
    • Higher pre-operative serum creatinine level
    • Poorer pre-operative lung function testing
    • Greater degree of surgical resection

  • If ongoing ventilation is required, use:
    • Lower tidal volumes e.g. 6ml/kg
    • Low-ish PEEP e.g. 5cmH2O
    • A target plateau pressure <25cmH2O

Oxygenation

  • Oxygen requirements tend to be higher initially post-operatively, which usually reflects residual atelectasis/collapse
  • This typically resolves readily, especially with manoeuvres such as application of suction to pleural drains

  • Increasing oxygen requirements may be a sign of infection or pulmonary oedema
  • This should be treated early and aggressively, with consideration for non-invasive respiratory support

  • Most thoracic surgical procedures require placement of wide-bore intercostal chest drains
  • Typically for drainage of air to allow re-expansion of the lung, but may be placed for drainage of empyema, blood or pleural effusions
  • Not typically required post-pneumonectomy
  • The use of underwater seals reduces the entrainment back into the pleural cavity, even with deep inspiratory effort e.g. intrapleural pressure -80cmH2O

  • Optimal management includes:
    • Minimise number of chest drains placed, ideally only one

    • Avoid routine use of suction

    • When necessary, suction can be applied e.g. -2kPa to -4kPa
      • Allows better re-expansion of the lung
      • Encourages drainage of air/fluid
      • Not appropriate in the case of air leak or bronchopleural fistula, where suction may potentiate the problem

    • Tolerate up to 450ml/24hr pleural fluid output as still being acceptable for drain removal
    • Remove drain as soon as possible

  • Relative fluid restriction in the post-operative period e.g. 13-20ml/kg total over 24hrs
    • Use balanced crystalloids aiming for euvolaemia
    • Early return to the enteral route for hydration is preferable

  • Reduce risk/degree of sputum retention
    • Adequate physiotherapy
    • Humidified oxygen
    • Sometimes mini-tracheostomy for sputum management, although the evidence base is weak and recommendation for this is low

  • Adequate analgesia i.e. manage thoracotomy pain
  • Early mobilisation
  • Early physiotherapy
  • Ensure adequate VTE prophylaxis

Acute lung injury

  • Complicates 4-10% of pulmonary resections
  • It is associated with a high (50-70%) mortality
  • Aetiological processes include:
    • Ventilator-induced lung injury due to volutrauma, barotrauma or atelectotrauma
    • Surgical instrumentation, with the incidence related to the degree of resection
    • Lung collapse

  • Risk is reduced by using lung-protective ventilation during one-lung ventilation

Cardiac arrhythmias

  • AF (40% overall) | Atrial flutter | SVT
  • More common in patients with pre-existing cardiac disease, who are older or of male gender
  • A proportion are due to post-operative infection
  • Associated with prolonged hospital stay and increased morbidity
  • Management:
    • Avoid β-blocker withdrawal pre-operatively in patients receiving them
    • Ensure normal magnesium levels
    • Only weak evidence for prophylaxis with amiodarone or diltiazem in those at higher risk
    • Treat arrythmias with negative chronotrope of choice, usually amiodarone or β-blockers

Other cardiac complications

  • Myocardial ischaemia following thoracic surgery is both more common (3 - 5%) and associated with a higher mortality (40 - 70%) than in the general surgical population

  • Haemodynamic instability
    • Should prompt consideration of occult blood loss, as the thoracic cavity can hold large volumes (of blood)
    • Malpositioned, kinked or otherwise occluded drains may contribute to this
    • Over-administration of crystalloids or colloids may worsen lung injury, so early use of vasoactive drugs may be preferable

Pulmonary oedema

  • Occurs in 2-5% of patients, usually within 72hrs of surgery
  • It is more likely to occur following right pneumonectomy
  • It carries a high mortality (>50%)

Cardiac herniation

  • A rare complication of:
    • Right-sided pneumonectomy if there has been stripping of the pericardial sac
    • Intra-pericardial pneumonectomy
  • Acute hypotension/shock and cyanosis with evidence of SVC obstruction
  • Requires urgent surgery
  • 50% mortality

Bronchopleural fistula