Endobronchial Cryotherapy

1. Endobronchial
Cryotherapy
D R . M D . S H A F I Q U L I S L A M D E WA N
R E S I D E N T ( P U L M O N O L O G Y )
R E S P I R A T O R Y M E D I C I N E D E P A R T M E N T
D H A K A M E D I C A L C O L L E G E H O S P I T A L

2. Endobronchial Cryotherapy
Several bronchoscopic cryosurgical techniques are available that employ
extremely low temperatures to freeze tissue for destruction (cryoablation),
adhesion (cryoadhesion), or biopsy(cryobiopsy).
The most common of these is cryoablation, a procedure that is mostly used to
manage inoperable airway obstruction.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 2

3. Equipment
Bronchoscopic cryotechniques require a cryosurgery device (ie, cryoprobe or
cryoforceps), bronchoscope and cooling agent (ie, cryogen).
Only experts skilled in the use of this equipment should perform cryosurgery.
The procedure can be performed in the operating room or specialized
procedure suites.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 3

4. Cryosurgery device
 Cryosurgery devices consist of_
1) Cryoprobe (ablative or adhesive procedures) or cryoforceps (biopsy procedures)
2) Transfer line
3) Console
The cryoprobe/forceps is used to freeze the target tissue.
The transfer line connects the cryoprobe/forceps to both the cooling agent storage container
(eg, gas cylinder) and the console.
The console controls the flow of cooling agent through the transfer line.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 4

5. Cryoprobes and Bronchoscope
Cryoprobes may be rigid, semirigid, or flexible.
Rigid cryoprobes have a system of reheating that induces a nearly immediate
thaw phase, whereas thawing is a passive process with flexible cryoprobes, such
that the freeze-thaw cycle is longer with the latter.
Cryoforceps are typically flexible.
Rigid and semi-rigid cryoprobes can be used through a rigid bronchoscope
only.
Flexible cryoprobes and forceps can be used through either a flexible or a
rigid bronchoscope.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 5

6. Cooling agents (cryogen)
1) Nitrous oxide (N2O)
2) Liquid nitrogen (LN2)
Choosing among these agents is often dependent upon availability, clinician
experience, and institutional biases.
While research data are not available, most clinicians seem to prefer using
N2O because larger freeze zones from LN2 exposes tissues to greater shear
damage, and therefore possible perforation.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 6

7. Flexible cryoprobe
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 7

8. Cryoablation
Cryoablation (also known as cryotherapy) uses exceptionally low
temperatures to destroy tissue with repeated cycles of rapid freezing and slow
thawing of target tissue.
Cryo-sensitive tissues include the skin, mucous membrane, granulation
tissue, and tumor cells.
Cryo-resistant tissues include fat, cartilage, fibrous, and connective tissue (ie,
normal airway).
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 8

9. Basic principles and mechanisms of action
Freezing tissue to -20°C or below, at a rapid rate (-100°C per minute) results in
the development of intracellular ice crystals which induce more than 90 percent
cell death.
Tissue is thawed slowly to allow intracellular crystals to increase in size before
they melt, resulting in further tissue destruction.
Intracellular ice crystals cause cell death by the following mechanisms:
• Damaging mitochondria or other micro-organelles.
• Cellular dehydration.
• Increased concentration of intracellular electrolytes.
• Denaturation of membrane lipoproteins resulting in cellular swelling and increased
permeability.
The depth of tissue penetration is approximately 3 mm, however this depends on the freeze
time and cryo-sensitivity of the tissue.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 9

10. Principles of cryoablation
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 10

11. Indications
Bronchoscopic cryoablation is primarily a palliative or adjunctive therapy
used for the relief of inoperable symptomatic central airway obstruction
(CAO)_
• Most commonly, CAO due to malignant conditions.
• Less commonly, CAO due to nonmalignant conditions.
• Rarely, used to treat hemoptysis or inoperable microinvasive lung carcinoma.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 11

12. DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 12

13. Nonmalignant Conditions
Nonmalignant conditions that have been successfully treated with
bronchoscopic cryotherapy include the following_
 Granulation tissue due to bronchial anastomoses following lobectomy or lung
transplantation
 Endobronchial lipoma, hamartoma, and hemangioma
 Blood clots
 Mycetoma
 Endobronchial tuberculosis
 Removal of mucus plugs
 Removal of foreign bodies
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 13

14. Contraindications
Extrinsic airway compression.
Contraindications to bronchoscopy.
Need of immediate relief of airway symptoms.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 14

15. Follow-up
Postoperative care: Bronchoscopic cryoablation does not require any
particular immediate follow-up care in the absence of complications, other than
routine post-bronchoscopy care.
Patients usually can return home the same day when performed as an
outpatient procedure.
However, the expectoration of debris and blood is not uncommon in the days
or weeks following cryoablation.
Atelectasis should be prevented with incentive spirometry and/or
chestbphysical therapy. For this reason, repeat bronchoscopy is generally
required.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 15

16. Steroid and Antibiotic
Corticosteroids are generally not needed, but they are sometimes
administered for 24 hours following cryosurgery on a tracheal or subglottic
lesion if the risk of airway compromise is judged to be high.
Antibiotics are not administered unless post obstructive pneumonia is evident.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 16

17. Repeat bronchoscopy
Repeat bronchoscopy (usually flexible bronchoscopy) is generally performed 2
to 10 days after bronchoscopic cryoablation.
The repeat examination allows the extent of tissue destruction to be assessed,
assure a clear and clean airway, and removal of devascularized cryo-ablative
debris by forcepsor cryoadhesion.
Additional bronchoscopic cryotherapy can be performed during the repeat
examination, if necessary.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 17

18. Cryoadhesion
Cryoadhesion refers to the use of a cryoprobe to freeze freely mobile
endoluminal material (eg,foreign body).
Material is generally frozen to temperatures of -40ºC or below. Frozen target
material adheres to the probe so that it can be removed.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 18

19. Cryobiopsy
This technique involves subjecting tissue to cryofixation by a liquid cryogen to
preserve tissue for subsequent morphologic and immunohistochemical analysis.
It theoretically avoids artifacts common to conventional preparation methods (eg,
crush or fixation-induced artifacts).
Cryoforceps quickly freezes the target biopsy material at the temperature of liquid
nitrogen(-196ºC).
Similar to cryoablation, tissue type can affect the efficacy of this biopsy modality such
that lung tissue is more amenable than cartilage to cryobiopsy.
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 19

20. Complications
Bronchoscopy or sedation-related
Cryotherapy-related
 Hemorrhage
 Airway wall ulceration and perforation
 Airway edema and mucus plugging
 Others (rare): air embolism and fistula formation
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 20

21. Cryotherapy
Time to Achieve
Results
Advantages Disadvantages
48–72 hr
• Normal airway is cryo-
resistant
• Can use in high-Fio2
environments
• Delayed maximal effect
• Requires “cleanout”
bronchoscopy
DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 21

22. DR. MD. SHAFIQUL ISLAM DEWAN, RESIDENT (PULMONOLOGY), DMCH 22
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