1. Bronchoscopic Cryotherapy
MGR Review
Bronchoscopic Cryotherapy
호흡기내과 R4 박유민 / Prof 박명재

2. Introduction Definition
Cryotherapy(also known as cryosurgery) is the therapeutic application of extreme cold for the local destruction of living tissue

3. Cryoadhesion Related phenomenon
It refers to using a cryoprobe to freeze material, thereby causing the material to adhere to the cryoprobe so that it can be removed

4. Basic principles
The core temperature needed for a lesion to be destroyed is between -20ºC and -40ºC
Freezing to -40ºC or below at a rapid rate (-100ºC per minute) results in more than 90 percent cell death
The tissue should be thawed slowly

5. Increase in size of intracellular ice crystals
Intracellular ice crystals can cause cell death directly by damaging mitochondria or other micro-organelles
Cellular dehydration and a toxic increase in the concentration of intracellular electrolytes
The result is cell swelling and rupture

6. Induces microvascular changes
Initial vasoconstriction of arterioles and venules
Modification of vascular endothelium
Increased permeability of vascular walls
Increased blood viscosity
Lower intracapillary hydrostatic pressure
Decreased blood flow
Formation of platelet plugs
Thrombosis of the feeding vessels

7. The amount of tissue destroyed by cryosurgery
Cooling/thawing rate
The minimal temperature achieved
The water content of the cells
The number of freezing and thawing cycles
The sensitivity of the tissue
Cryosensitive : skin, mucous membrane, granulation tissue, and tumor cells
Cryoresistant : fat, cartilage, fibrous, and connective tissue

8. Equipment Bronchoscope Cooling agent(Cryogen) Cryosurgery device
(Cryoprobe+transfer line+console)

9. Equipment Bronchoscope(rigid or flexible) Cooling agents
Liquid nitrogen(N2) and nitrous oxide(NO2)
Joule-Thomson effect

10. Equipment Cryosurgery device
Cryoprobe : used to freeze the target tissue
Rigid, Semirigid : rigid bronchoscope only
Flexible : either a flexible or a rigid bronchoscope

11. Transfer line : line connects the cryoprobe to both the cooling agent storage container
Console : controls the flow of cooling agent through the transfer line

12. Indication
A palliative therapy for airway obstruction due to a malignancy
Usually in patients who cannot tolerate lung resection (Poor respiratory function, inoperable due to the proximity of the tumor to the carina, underlying health conditions)
Airway obstruction due to benign endotracheal or endobronchial lesions
Inoperable microinvasive carcinoma, and hemoptysis due to visible benign or malignant lesions
Cryoadhesion can be used to extract foreign bodies, mucous plugs, or blood clots and biopsy specimen

13. Follow-up bronchoscopy
Generally performed eight to ten days after bronchoscopic cryosurgery
The repeat examination allows the extent of tissue destruction to be assessed
Sloughing material can be removed by forceps, aspiration, or cryoadhesion
If necessary, additional bronchoscopic cryotherapy can also be performed

14. Possible complications
There are few cryosurgery-specific contraindications
Hemorrhage
Pneumothorax/Subcutaneous emphysema
Reactive airway edema
Complictaion due to extracted tissue migration
Anesthesia related complications

15. Procedure
The preparation and initiation of bronchoscopic cryosurgery are identical to that for conventional flexible or rigid bronchoscopy
Pooling-out using cryoadhesion for recanalization, and biopsy
Repeating freezing/thawing for devitalization

16. Clinical outcomes Treatment of airway obstruction
Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review
Korean J Intern Med 2011;26:

17. Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review
Korean J Intern Med 2011;26:

18. Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review
Korean J Intern Med 2011;26:

19. Endoscopic cryotherapy generally showed high treatment efficiency in approximately 80% of cases, although there was variation depending on operation methods or target patient groups
It was also effective in improving quality of life, improving symptoms, like dyspnea, and improving pulmonary function
Endoscopic Cryotherapy of Lung and Bronchial Tumors: A Systematic Review
Korean J Intern Med 2011;26:

20. Clinical outcomes Biopsy using cryoadhesion
Cryobiopsies extracted from perfused tissue are larger than forceps biopsies
Prospective Controlled Animal Study on Biopsy Sampling with New Flexible Cryoprobes versus Forceps: Evaluation of Biopsy Size, Histological Quality and Bleeding Risk
Respiration 2010;80:127–132

21. Cryospecific artifacts were not observed
Cryobiopsies are structurally intact, and tissue integrity is not impaired by the freezing process
The artifact-free area was 95% for both, forceps and cryobiopsy samples
Cryospecific artifacts were not observed
Prospective Controlled Animal Study on Biopsy Sampling with New Flexible Cryoprobes versus Forceps: Evaluation of Biopsy Size, Histological Quality and Bleeding Risk
Respiration 2010;80:127–132

22. Conclusion
Endobronchial cryotherapy is an effective and less expensive procedure for the management of central airway obstruction
Tissue biopsy using cryotherapy is very effective