Postoperative Free Flap Monitoring

1. POST OPERATIVE
FREE FLAP MONITORING
Dr. Akshai George Paul
DNB Resident
Department of Plastic surgery
Aster MIMS Calicut

2. What is Flap???
• A flap is a unit of tissue that maintains its own
blood supply while being transferred from a donor
site to a recipient site

7. What is Free Flap?
A unit of tissue that has a pedicle consisting of a
feeding artery and a draining vein. The pedicle is
anastomosed to an artery and vein at the recipient
site to reestablish blood flow to the unit of tissue

10. Why Flap Monitoring??
Early detection and intervention
of flap problems can improve
overall flap salvage

11. Ideal Flap Monitoring technique
• Reliable
• Non invasive
• Objectively repeatable
• Promptly reactive to blood flow changes
• Appropriate for all free tissue transfers
• Usable for Unskilled
• Economically Feasible

12. General Conditions of patient
• Monitoring vitals- BP, HR, Temperature
• Urine output
• Pain Management
• Hydration
• Nutrition
• Hemoglobin

13. 1)Blood pressure-
SBP maintained ~120 and MAP >90
• sudden fluctuations cause turbulent flow within
flap or through anastomosis.
• Hypotension- arterial spasm and venous stasis
cause thrombosis
• Hypertension-(>180/100) can lead to bleeding

14. • Rule out arrhythmias- close monitoring in ICU
• Avoid ionotropes – peripheral vasoconstriction
• Adequate pain control – pain cause hypertension
• Anemia correction- Hb and hematocrit to be
performed 4-5 hr postoperatively and then daily,
for 3 days.
• Avoid compression over anastomosis

15. 2)Urine output:
• Atleast 0.5ml/kg/hr of urine (~50 to 100 ml/hr)
• Do not use diuretics to induce urine
• 3)Temperature
• Keep warm
• Hypothermia can Cause vasospasm
• Heating units or warmers for 5 days.

16. • Adequate hydration and Nutrition
• Systemic antibiotics
• Pain Management-Pain Can cause Hypertension
and flap compromise
• Drains and Catheters to be Managed accordingly

17. FLAP
MONITORING

19. • BUT NONE OF THE ONES BEEN COMPLETELY
RELIABLE OR UNIFORMLY
ACCEPTABLE

20. Non invasive Methods

21. Clinical Assessment
(Gold Standard)
• flap skin color and Turgor
• surface temperature,
• rate of bleeding with pinprick or scratch,
• capillary refill time
• Muscle contraction in muscle flaps- Not a good
parameter

22. Healthy flap
• Healthy flap will be warm, pink, soft, with a
capillary refill of approximately 2 seconds
• Frequency of evaluation:
• Half Hourly monitoring in first 24 hours
• 1-2 hourly in second 24hours
• 4th hourly on the following 2 days

24. Arterial compromise

25. Venous compromise

26. Cutaneous Hand Held Doppler
• It is widely available and can be used as an adjunct
to clinical methods
• But it can be influenced by near by vessels and can
give false results

27. USG Color Doppler
• To assess velocity and rate of flow
• But it requires expertise of a radiologist and other
resources and it's costly considering to other
methods
• It is useful in buried flaps before taking to
exploration

28. Laser Doppler
Laser Doppler measures the reflected waveforms of
light, from a helium–neon laser, by the red blood
cells moving within the capillaries.

29. Microlight guided spectrometry
• Calibrated IR light delivered to tissue via light
source probe
• Detector to measure absorbed and scattered light
at different wavelengths
• Can measure relative changes of oxygenated,
deoxygenated, total Hb concentration, and oxygen
saturation in tissue.

30. • Venous thrombosis- deoxy and total Hb
increases//oxy Hb and O2 saturation decreases.
• Arterial thrombosis- deoxy increases// total hb, oxy
hb, O2 saturation decreases
• Drawback- expensive

31. Surface temperature monitoring
• First introduced in 1956
• Hand held IR thermography camera
• Measure subtle changes in flap surface
temperature
• Difference of >1.8 degree C for Flap and Control site
is predictive
• Temperature below 30 degree C indicate of flap
failure.

32. Oxygen saturation/Tissue /pulse
oxymetry
• Less use ful in free muscle flap
• Used in Replants and toe transfers

33. Invasive Methods

34. Implantable Doppler
• First introduced in 1988 referred to as cook-swartz
Doppler
• 20MHz US probe with 1mm 2 piezoelectric crystal
embedded in soft silicone sleeve.
• Sutured directly to blood vessel distal to vascular
anastomosis.
• Left insitu for 7 days postop
• Continuous monitoring regarding the anastomosis
status-so that any compromise deteccted instanta

37. Flow coupler Device
• Venous coupler by Synovis
• Doppler probe integrated into venous coupler to
create a venous anastomosis.
• Monitor has 2 indicators- signal quality, venous
saturation
• Venous oxygen saturation for a healthy flap –
constant flat line with minimal fluctuations.

39. Transcutaneous oxygen tension
• PO2 measured using capillary blood gas analysis in
skin flaps – helps in predicting viability of flap
• Difference in pO2 measured using capillary blood
gas analysis and fingertip- predict chances of skin
flap failure.
• If pO2 <86.3mmHg- revise the flap to avoid failure

40. Tissue pH Monitoring
• A pH below 7.3 or a difference of >0.35 compared
to control suggest a problem, greater the difference
and faster it develop, more likely it's, arterial
problem

41. Microdialysis
• Insertion of small catheters into sc tissue to
measure metabolites such as glucose and lactate
and pyruvate at intervals
• Every 30 min for first day, every hr for next day etc.
• A low glucose and high lactate are warning signs

42. Tc 99m SestamibiSestamibi
scintigraphy
• sestamibi scintigraphy appears to be a feasible and
promising method in the evaluation of free muscle
flap viability and complications- Not Used widely

43. Contrast Enhanced Doppler
• Indocyanin green is used
• Helps identify zones of perfusion before
committing to flap design

44. Fluroscein Imaging
More than 70 % accurate as an indicator of
circulatory status of flap
After waiting 20-30 min extend of dye staining in
tissues that are adequately perfused can be seen
with woods lamp

45. Perfusion weighted MRI
• MRI perfusion imaging as a promising post-surgery
monitoring in patients with free flaps.-Not used
widely studies are going on

47. Flaps are beautiful✨✨

48. • 45 yr old male RTA with a composite defect on Left
mid leg. Under went multiple debridement + VAC.
Followed by LD free flap

50. • 24 yr old male RTA- Soft tissue defect medial aspect
of Left distal leg and foot. Multiple debridement
and VAC done. Then Gracialis free flap

52. • 62 yr female with non healing ulcer left distal
medial leg and foot. Multiple debridement vac
done. Then Gracialis free flap.

54. 66 yrs old male with Buccoalveolar Ca
underwent WLE + ALT Free flap under GA