Methods of determining tissue viability

1. A method of determining viability of subject tissue, comprising:

determining a local perfusion pressure of the subject tissue of a patient by applying pressure to the subject tissue using a tissue grasper;

determining a systemic blood pressure of the patient;

calculating a first index using the determined local perfusion pressure and the determined systemic blood pressure;

reducing a temperature of the subject tissue from a baseline temperature to a temperature below the baseline temperature by contacting the subject tissue with pre-chilled tissue contacting surfaces of the tissue grasper;

generating an infrared image of the subject tissue using a thermographic camera;

analyzing the infrared image to determine a rate at which the subject tissue returns to the baseline temperature from the temperature below the baseline temperature; and

determining viability of the subject tissue based on the first index and the determined rate.

2. The method according to claim 1 , further comprising:

assigning a numerical value to the subject tissue based on the determined rate; and

comparing the numerical value to a known numerical value corresponding to viable tissue to determine the viability of the subject tissue.

3. The method according to claim 2 , wherein determining the viability of the subject tissue further includes comparing the first index to a known first index corresponding to viable tissue.

4. The method according to claim 1 , further comprising stapling the subject tissue upon determining that the subject tissue is viable.

5. The method according to claim 1 , further comprising comparing the infrared image of the subject tissue with an infrared image of healthy tissue to determine whether the subject tissue exhibits normal blood flow characteristics.

6. The method according to claim 1 , wherein the subject tissue is a pair of bowel segments.

7. The method according to claim 6 , further comprising resecting a portion of at least one of the pair of bowel segments upon determining that the portion is not viable.

8. The method according to claim 7 , further comprising stapling ends of the pair of bowel segments to reconnect the pair of bowel segments upon determining that the ends of the pair of bowel segments are viable.

9. The method according to claim 8 , wherein determining that the ends of the pair of bowel segments are viable includes analyzing the infrared image to determine whether the ends of the pair of bowel segments exhibit normal heat distribution characteristics.