With respect to open or video-assisted thorascopic surgical lung biopsy in the management of respiratory failure in the critically ill, discuss the indications, advantages, limitations and complications.

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College Answer

Indications
Not common.
Usually performed in setting of progressive and non resolving respiratory failure/ARDS where no
aetiologic diagnosis has been reached by conventional testing such as:
 Radiological techniques
 Microbiological/serological/histological examination of sputum and secretions
o Bronchoscopic samples required
 Radiologically guided (CT or ultrasound) biopsies
 Serological testing

Decision to perform lung biopsy based on:
The need to make a specific diagnosis and thereby direct specific treatment
With-hold potentially harmful or ineffective empiric treatment when other investigations including biopsy obtained by less invasive techniques have been inconclusive
Provide important prognostic information

Diagnostic/therapeutic advantages
May be useful in identifying a range of potentially treatable pathologies

  • Infectious
    • Bacterial
    • Viral
    • Fungal
    • Other e.g. PJP
  • Inflammatory
    • COP (cryptogenic organising pneumonia aka BOOP)
    • Other interstitial pneumonias
    • Connective tissue disease
    • Capillaritis etc.

May diagnose other less treatable pathologies that may alter directions of treatment (limitation of care
or palliation)
 Malignant disease
 Fibrotic disease e.g. IPF
 Other : e.g. veno-occlusive disease

Potentially avoid administration of high dose steroids or other potent immunosuppressants if concern
exists about a possible infectious aetiology.

Also may allow cessation of unnecessary/toxic anti-infective medications.
 However, if all such treatments are initiated empirically then it is often argued that the
procedure is unnecessary (see “limitations” below)
Obtain larger and/or multiple samples
Ability to treat co-existing pathology e.g. perform pleurodesis, drain empyema simultaneously

Limitations
May be difficult to know where best to biopsy (especially if radiology unhelpful) or the most likely
useful area may be inaccessible to the surgeon.
May not give useful diagnostic information especially if not performed early enough,
If all treatment modalities are administered empirically, the value of the test is debatable.

Potential complications

General
Bleeding, infection, poor wound healing etc.

Specific
Increased analgesia requirements post open procedure
Pneumothoraces (persistent/tension etc.)
Persistent air leak (may be prolonged >7 days)(difficult to treat): most common Cx
Haemothorax, massive haemorrhage, pseudotamponade, circulatory collapse
Serous effusions, empyema
Need for single lung ventilation during surgery (VATS)
 Respiratory decompensation intra/post procedure
Death
May not obtain adequate sample

Summary statement (for example)
There is no high-grade evidence for its utility in this context. However, there are multiple case series in the literature that describe high rates of specific diagnostic yield (65-95%), with results leading to treatment alterations in the majority of cases (42 – 89%). All series had a low serious complication rate, and air leaks were the commonest complication.

Additional Examiners’ Comments: Some candidates misread the question as ‘compare and contrast’

Overall well answered.

Discussion

The LITFL lung biopsy page is a definitive resource for the time-poor exam candidate.

In summary:

  • Only do it if the other modalities have failed.
  • If you're going to do it, do it early.
  • It may have no impact on mortality, even if you achieve the correct diagnosis.

Rationale for an open lung biopsy

  • Diagnosis of lung disease cannot be established by less invasive means (eg. BAL, bronchoscopic biopsy, HRCT, serological testing and PCR analysis of secretions)
  • The lung disease is not responding to the current management
  • Management for the differentials is substantially different and a tissue diagnosis will alter the course of management
  • The management suggested has significant side effects, and a biopsy may prevent such management
  • Prognosis will be influenced by tissue diagnosis, and may be grounds for a palliative course of management
  • "While you're there": at the same time as the biopsy, some sort of helpful treatment may be performed in theatre (eg. drainage of an empyema or talc pleurodesis)

Potential findings from a lung biopsy:

  • Pointless and late: a small amount of non-diagnostic necrotic lung was biopsied.
  • Infectious aetiology
    • Bacterial
    • Viral
    • Fungal
    • Other e.g. PJP
  • Inflammatory aetiology
    • COP (cryptogenic organising pneumonia aka BOOP)
    • Other interstitial pneumonias
    • Connective tissue disease
    • Capillaritis etc.
  • Untreatable aetiology (resulting in a change of the goals of care)

Complications of lung biopsy

  • pneumothorax
  • bronchopleural fistula
  • haemothorax
  • major vessel damage
  • failure to establish a diagnosis due to poor sampling
  • Failure of procedure (aborted procedure) due to poor tolerance of single-lung ventilation
  • death
  • The biopsy must be performed in several regions of the lung, and must yield specimens which offer a representative sample, without sampling any areas of irreversible fibrosis or uninformative necrosis.  It cannot be performed in patients who cannot be ventilated on one lung for prolonged periods. Risks and contraindications of of thoracotomy apply.

Evidence in support of lung biopsy

In their answer, the college mention some numbers from "multiple case series in the literature". It would be lovely if they gave a reference.

  • High rates of specific diagnostic yield (65-95%)
  • Results leading to treatment alterations in the majority of cases (42 – 89%).

Even in 1976 (Hill et al) the mortality rate from this procedure was zero, and the morbidity rate was around 4%. In that ancient case series, 33% of the patients enjoyed some sort of positive change in their management because of the biopsy result.

Flabouris and Myburgh (1999) reported something similar. Their complication rate was higher (21%) but these were "proper" mechanically ventilated ICU patients. "Open lung biopsy-guided alteration of therapy directly benefited 39%, and withdrawal was possible in 8.4% of the patients". However, the change to management did not discriminate survivors from non-survivors (i.e. it didn't matter that you changed to an appropriate therapy, the patient died anyway).

A  retrospective series by Lim et al (2007) also reported that a specific diagnosis was achieved in 86% of the biopsied patients, and that in 64% changes to management occurred. Those who were biopsied earlier (within 1 week of intubation) did better in terms of mortality (63% survival vs 11%), which contrasts with the earlier studies.

References