Australian Clinical Guidelines for Radiological Emergencies - September 2012

Pulmonary Lavage

Page last updated: 07 December 2012

Introduction

Bronchopulmonary lavage as a procedure for washing out the lungs was developed as an experimental procedure in the 1920s. The clinical indications for human use have been evolving since the 1960s.

For treatment of inhaled insoluble radionuclides, bronchopulmonary lavage aims to reduce the lung burden using sequential whole lung lavage, repeated as tolerated on alternate lungs over an extended period.

On review of the literature a search for the term “bronchopulmonary lavage” reveals a number of procedures.
  1. Diagnostic pulmonary lavage: the instillation of 5 – 15 mL of isotonic saline into the trachea or bronchi and removed by suction. There may be a number of instillations. The effluent is sent for further analysis; cytological, microbiological or biochemical. This technique could be utilised to estimate lung burden of inhaled radionuclides.
  2. Segmental lung flooding: following the positioning of a single lumen endotracheal tube within the selected bronchus under local anaesthesia, up to 100 mL of isotonic saline is introduced. The fluid is removed by suction or expectoration, the objective being to loosen material within a segment or lobe of lung.
  3. Bronchopulmonary lavage or whole lung lavage is a procedure performed under general anaesthesia. A double lumen endotracheal tube isolates one lung, into which sufficient saline is instilled to fill the entire volume of one lung. The lung undergoing lavage is drained and repeatedly filled with fluid, and finally suctioned. The procedure is repeated on the alternate lung at another time. The objective of this procedure is to remove as much material from the lung as possible.
It is whole lung lavage which is discussed in this chapter. The term pulmonary lavage will be used to mean bronchopulmonary lavage or whole lung lavage.

Experimental uses of pulmonary lavage included:
  • study of the lung as a dialysis membrane
  • analysis of pulmonary surfactant
  • removal of radionuclides from the lungs of experimental animals
Clinical trials of pulmonary lavage have included:
  • obstructive airways disease
  • cystic fibrosis
  • status asthmaticus
  • pulmonary alveolar proteinosis
  • removal of accidentally inhaled 239Pu from a human subject in a single case report
top of pageOnly in pulmonary alveolar proteinosis, a condition with an incidence of 0.5 per 1,000,000 for the acquired form, is there continued substantive clinical experience of pulmonary lavage. In this condition, whole lung lavage is considered the gold standard for treatment.

The procedure for pulmonary lavage contained in the appendix to this chapter is taken from descriptions of the procedure as applied to pulmonary alveolar proteinosis. These procedures are consistent with the pulmonary lavage undertaken in experimental animals and the solitary case report of a human who accidentally inhaled plutonium. Additionally, the description of the procedure as applied to pulmonary alveolar proteinosis is consistent with current standards for monitoring under anaesthesia.

Efficacy

Pulmonary lavage is applied to inhaled materials with long lung retention times, generally those which are relatively insoluble. The technique appears to be equally effective for a variety of insoluble radionuclides. Inhaled material with a short retention time in the lung is generally removed by mucociliary clearance or absorption before it can be adequately removed from the lung by pulmonary lavage.

Experiments in beagle dogs, where each animal underwent 10 pulmonary lavage procedures from the second to the 56th day post exposure to various radionuclides, demonstrated removal of 23 to 59% (mean 44%) of the initial lung burden.

A single pulmonary lavage conducted sequentially on both lungs on the second day post exposure to various radionuclides in beagles and baboons demonstrated a reduction of 18 to 31% of the initial lung burden. Additional pulmonary lavages 3 to 7 days apart removed an average of 6% of initial lung burden on each of the 2nd to 6th occasions. This dropped to removal of 2% of initial lung burden on the 7th to 10th occasions, and 1% or less on the 11th to 20th occasions in other studies.

Further studies in dogs demonstrated that the efficacy of a single pulmonary lavage between day 2 and day 196 post exposure removed 8 to 40% consistently, compared with the residual lung burden immediately prior to each occasion of lavage. Hence the effectiveness of pulmonary lavage is not dependent on time after exposure where the substance has a relatively long biological half-life in the lung.

In dogs exposed to radionuclides with long retention times in lungs, the administration of DTPA (10 to 18 treatments) increased urinary excretion of radionuclides 3 to 5-fold compared with controls. However, the amount removed by chelation was only an average of 1.6% of the initial lung burden compared to 39 to 49% removed by pulmonary lavage (10 treatments) in the same animals.

The use of DTPA in the lavage fluid was equal in efficacy to intravenous administration and conferred no advantage.

In the single case report of a human with accidental inhalation of 239Pu, he underwent pulmonary lavage of the right lung on days 8 and 17, and left lung on day 12 after exposure. Intravenous DTPA was begun on day 8. Of the initial lung burden, 14% was removed by lavage, and 17% in the urine. The plutonium mixture was thought to be heterogeneous in solubility.
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Experiments in beagles have demonstrated that the distribution of inhaled radionuclide by activity and weight is usually 58% to the right lung and 42% to the left lung. The proportions are likely to be similar in humans. Thus, the right lung should be preferentially lavaged first in a series of pulmonary lavages in order to maximally reduce the initial lung burden.

With regard to the total volume of lavage fluid recommended, a total of 40 to 50 litres is advised for an adult patient. This is consistent with current guidelines for pulmonary alveolar proteinosis, and can be extrapolated from the volumes used in animal experiments for radionuclide removal by pulmonary lavage. Analysis of the radionuclide content of the lavage effluent in beagles, demonstrated that a significant proportion of the total radionuclide removed was contained in each fraction. Six litres was lavaged into each dog, with average weight of the dogs at 8.5 kg. Average values for each litre of lavage effluent of the percentage of radionuclide removed are contained in Table 13.1. The large volume ensures adequate washing. It is strongly recommended that, in humans, no less than 40 to 50 litres of lavage fluid be used.


Table 13.1 Burden of deposited radionuclide removed by lavage by episode of treatment
Lavage effluent fraction1st 2nd 3rd 4th 5th 6th/final
% of total radionuclide activity removed per lavage44299.34.93.59.8

Adapted from Boecker et al. Removal of 144Ce in fused clay particles from the beagle dog lung by bronchopulmonary lavage. Health Physics. 1974; 26: 505-517.

Benefits of pulmonary lavage

In a study comparing the efficacy of treatment in beagles exposed to 144Ce aerosols with pulmonary lavage and intravenous DTPA against untreated controls, 3 of 4 untreated animals died of pulmonary fibrosis, whereas 2 of the 8 treated dogs died. Only one of the surviving treated animals developed pulmonary fibrosis despite being observed for an appropriate period. Lung function was preserved in the other treated survivors.

In another study of beagles exposed to 241Am, treatment with pulmonary lavage (10 treatments) and intravenous DTPA (18 treatments) reduced absorbed radiation doses to lung, liver and skeleton by 50, 90 and 85% respectively.

Sequelae of pulmonary lavage

Pulmonary lavage results in improvement of lung function, including arterial oxygenation, in patients with pulmonary alveolar proteinosis. Therefore, significant functional impairment is not expected for patients undergoing pulmonary lavage to remove inhaled radionuclides.
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Chest films immediately following pulmonary lavage demonstrate diffuse opacification, which resolves within 24 to 48 hours post-procedure. Some transient atelectasis may occur.

Histological evidence of mechanical injury to lung parenchyma is minimised using a volume-controlled technique of pulmonary lavage.

Risks of pulmonary lavage

Mucociliary clearance of larger inhaled particles occurs in the initial period after inhalation. It has been demonstrated that greater than 60% of the inhaled dose deposited in the airways may be cleared in the first 2 days by this means. A theoretical risk exists of washing contaminants more deeply into the lungs with immediate pulmonary lavage. Although there is no experimental evidence to confirm this, a delay of several days to the initiation of pulmonary lavage has been recommended.

Premorbid conditions must be considered in evaluating the risk versus benefit for an individual patient with this procedure. The primary consideration is the risk of general anaesthesia against the future risk of radiation induced injury or neoplasia.

Leakage of fluid into the ventilated lung is of greatest concern. This is recognised by fluid in the lumen of the ventilated lung and air bubbles in the lavage fluid. The procedure must be stopped immediately, placing the patient in the lateral decubitus position with the lavaged side down, suctioning out both lungs and rechecking the position of the double lumen tube.

Electrolyte and fluid balance changes may occur due to the dialysate effect of the lavage fluid.

Transient right bundle branch block appears to be the most commonly reported electrocardiographic abnormality during the procedure.

Summary

Pulmonary lavage is effective at removing inhaled insoluble radionuclides. A single lavage will remove approximately 12% of the initial lung burden from one lung. Repeated lavage will remove up to 45% on average. The removal of insoluble radionuclide particles from the lungs decreases the cumulative dose, preventing radiation-induced injury.

The effectiveness of pulmonary lavage is not altered by delay after inhalation of the radionuclide. However, the radiation injury accumulates with increasing duration of exposure. Pulmonary lavage is a treatment aimed at reducing the likelihood of future injury. Current injuries and illnesses should be stabilised as a priority before lavage is undertaken.

Key determinants of the need for pulmonary lavage are:
  • the isotope and chemical form of the radionuclide inhaled (half-life and solubility known)
  • the particle size (which affects the likelihood of alveolar deposition)
  • the quantity of material inhaled (estimated from nasal swabs, lung and whole body counts, and / or indirectly from other bioassays)
top of pageThe chemical form and particle size of the aerosol is likely to vary if the radionuclide is dispersed during an explosion or fire as multiple temperatures and chemical reactions occur within the combustion process.

The procedure is justified for an insoluble radionuclide with a long retention time in the lungs where the cumulative dose is greater than 100 ALI. (Annual limit of intake for occupational exposure. One ALI is the maximum permissible exposure each year, without detectable health risk. One ALI corresponds to a committed effective dose equivalent of 0.05 Sv, or a committed effective dose equivalent of 0.5 Sv to any individual organ or tissue, whichever is the more limiting. The threshold dose for radiation pneumonitis is 5 Gy.)

There is no other technique available that will effectively reduce the lung burden of inhaled insoluble radioactive materials.

    References:

  1. Anantham D, Jagadesan R, Tiew PEC. Clinical review: independent lung ventilation in critical care. Critical Care. 2005; 9 (6): 594 – 600.
  2. Beccaria M, Luisetti M, Rodi G, Corsico A, Zoia MC, et al. Long-term durable benefit after whole lung lavage in pulmonary alveolar proteinosis. Eur Resp J. 2004; 23: 526 – 531.
  3. Boecker BB, Muggenburg BA, McLellan RO, Clarkson SP, Mares FJ, et al. Removal of 144Ce in fused clay particles from the beagle dog lung by bronchopulmonary lavage. Health Physics. 1974; 26: 505-517
  4. Guilmette RA, Muggenburg BA, Cambron BL. Bronchoalveolar lavage: a new bioassay tool for plutonium inhalation exposures. Journal of Occupational Medicine. 1986; 28: 492 – 496.
  5. Kylstra JA, Rausch DC, Hall KD, Spock A. Volume-controlled lung lavage in the treatment of asthma, bronchiectasis, and mucoviscidosis. American Review of Respiratory Disease. 1971; 103: 651 – 665.
  6. McClellan RO, Boyd HA, Benjamin SA, Cuddihy RG, Hahn FF, et al. Bronchopulmonary lavage and DTPA treatment of an accidental inhalation 239Pu exposure case. Fission product inhalation program annual report (Lovelace Foundation for Medical Education and Research). 1971 – 1972; 45: 287-294.
  7. Methods of Treatment. In Radiation Protection Dosimetry. Nuclear Technology Publishing; 1992; 41(1): 27-36
  8. Morgan C. The benefits of whole lung lavage in pulmonary alveolar proteinosis. Eur Resp J. 2004; 23: 503-505.
  9. Muggenberg BA, Mauderly JL, Boecker BB, Hahn FF, McLellan RO. Prevention of radiation pneumonitis from inhaled cerium-144 by lung lavage in beagle dogs. American Review of Respiratory Disease. 1975; 111: 795-802.
  10. Muggenburg BA, Felicetti SA, Silbaugh SA. Removal of inhaled radioactive particles by lung lavage - a review. Health Physics. 1977; 33: 213-220.
  11. Muggenburg BA, Jones RK. Clinical and experimental uses of bronchopulmonary lavage: a review. Fission product inhalation program annual report (Lovelace Foundation for Medical Education and Research). 1970 – 1971; 44: 319-322.
  12. Muggenburg BA, Mewhinney JA. Removal of inhaled 241Am oxide particles of various sizes from beagle dogs using lung lavage and chelation treatment. Health Physics. 1981; 41: 123-133.
  13. Nolibe D, Nenot JC, Metivier H, Masse R, Lafuma J. Traitement des inhalations accidentelles d’oxyde de plutonium par lavage pulmonaire in vivo. In : International Atomic Energy Agency. Diagnosis and treatment of incorporated radionuclides, proceedings series. IAEA. Vienna; 1976: 373-385.
  14. Pfleger RC, Wilson AJ, Cuddihy RG, McLellan RO. Bronchopulmonary lavage for removal of inhaled insoluble materials from the lung. Chest. 1969; 56: 524-530.
  15. Ramirez-R J. Pulmonary alveolar proteinosis – treatment by massive bronchopulmonary lavage. Arch Intern Med. 1967; 119: 147-156.
  16. Seymour JF, Presneill JJ. Pulmonary Alveolar Proteinosis. Am J Respir Crit Care Med. 2002; 166: 215-235.

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