Evaluation of Tissue Oxygen Measurements for Flap Monitoring in an Animal Model

ABSTRACT

Tissue oxygen tension (p_tiO₂) measurements are common in neurosurgery but uncommon in plastic surgery. We examined this technique as a monitoring method with probe placement in the subcutaneous tissue and addressed the importance of probe placement. Myocutaneous flaps were raised in an animal model and p_tiO₂ measurements performed at different levels in the subcutaneous fat. Flap artery and vein were occluded until a 50% p_tiO₂ reduction had occurred (T_1/2). We found no significant effect of depth (p > 0.10) on the level of p_tiO₂. T_1/2 ^arterial was 7.2 minutes and T_1/2 ^venous was 18 minutes. We found no significant relation between intitial levels of p_tiO₂ and T_1/2. Location of the probe and absolute p_tiO₂ value is of little relevance for flap monitoring. It is the relative change in p_tiO₂ that is important. The p_tiO₂ technique is well suited for monitoring in the subcutaneous tissue and is highly sensitive to changes in both arterial and venous blood flow.

Tissue oxygen tension - perfusion monitoring - blood flow

REFERENCES

• 1 Khouri R K, Cooley B C, Kunselman A R et al.. A prospective study of microvascular free-flap surgery and outcome.  Plast Reconstr Surg. 1998;  102 711-721
• 2 Schusterman M A, Kroll S S, Miller M J et al.. The free transverse rectus abdominis musculocutaneous flap for breast reconstruction: one center's experience with 211 consecutive cases.  Ann Plast Surg. 1994;  32 234-241
• 3 Blondeel P N. One hundred free DIEP flap breast reconstructions: a personal experience.  Br J Plast Surg. 1999;  52 104-111
• 4 Neligan P C. Monitoring techniques for the detection of flow failure in the postoperative period.  Microsurgery. 1993;  14 162-164
• 5 Heller L, Levin L S, Klitzman B. Laser Doppler flowmeter monitoring of free-tissue transfers: blood flow in normal and complicated cases.  Plast Reconstr Surg. 2001;  107 1739-1745
• 6 Salmi A, Ahovuo J, Tukiainen E, Harma M, Asko-Seljavaara S. Use of ultrasonography to evaluate muscle thickness and blood flow in free flaps.  Microsurgery. 1995;  16 601-605
• 7 Khouri R K, Shaw W W. Monitoring of free flaps with surface-temperature recordings: is it reliable?.  Plast Reconstr Surg. 1992;  89 495-499
• 8 Jones N F. Intraoperative and postoperative monitoring of microsurgical free tissue transfers.  Clin Plast Surg. 1992;  19 783-797
• 9 Furnas H, Rosen J M. Monitoring in microvascular surgery.  Ann Plast Surg. 1991;  26 265-272
• 10 Udesen A, Lontoft E, Kristensen S R. Monitoring of free TRAM flaps with microdialysis.  J Reconstr Microsurg. 2000;  16 101-106
• 11 Jones B M. Monitors for the cutaneous microcirculation.  Plast Reconstr Surg. 1984;  73 843-850
• 12 Hirigoyen M B, Blackwell K E, Zhang W X, Silver L, Weinberg H, Urken M L. Continuous tissue oxygen tension measurement as a monitor of free-flap viability.  Plast Reconstr Surg. 1997;  99 763-773
• 13 Kamolz L P, Giovanoli P, Haslik W, Koller R, Frey M. Continuous free-flap monitoring with tissue-oxygen measurements: three-year experience.  J Reconstr Microsurg. 2002;  18 487-491
• 14 Wechselberger G, Rumer A, Schoeller T, Schwabegger A, Ninkovic M, Anderl H. Free-flap monitoring with tissue-oxygen measurement.  J Reconstr Microsurg. 1997;  13 125-130
• 15 Maas A I, Fleckenstein W, de Jong D A, van Santbrink H. Monitoring cerebral oxygenation: experimental studies and preliminary clinical results of continuous monitoring of cerebrospinal fluid and brain tissue oxygen tension.  Acta Neurochir Suppl (Wien). 1993;  59 50-57
• 16 Manley G T, Hemphill J C, Morabito D et al.. Cerebral oxygenation during hemorrhagic shock: perils of hyperventilation and the therapeutic potential of hypoventilation.  J Trauma. 2000;  48 1025-1032
• 17 Manley G T, Pitts L H, Morabito D et al.. Brain tissue oxygenation during hemorrhagic shock, resuscitation, and alterations in ventilation.  J Trauma. 1999;  46 261-267
• 18 Daniel R K, Williams H B. The free transfer of skin flaps by microvascular anastomoses. An experimental study and a reappraisal.  Plast Reconstr Surg. 1973;  52 16-31
• 19 Kerrigan C L, Zelt R G, Thomson J G, Diano E. The pig as an experimental animal in plastic surgery research for the study of skin flaps, myocutaneous flaps and fasciocutaneous flaps.  Lab Anim Sci. 1986;  36 408-412
• 20 Horch R, Stark G B. Prosthetic vascular graft infection–defect covering with delayed vertical rectus abdominis muscular flap (VRAM) and rectus femoris flap.  Vasa. 1994;  23 52-56
• 21 Baumgartl H, Zimelka W, Lubbers D W. Evaluation of PO(2) profiles to describe the oxygen pressure field within the tissue.  Comp Biochem Physiol A Mol Integr Physiol. 2002;  132 75-85
• 22 Simonsen L, Enevoldsen L H, Bulow J. Determination of adipose tissue blood flow with local 133Xe clearance. Evaluation of a new labelling technique.  Clin Physiol Funct Imaging. 2003;  23 320-323
• 23 Ardilouze J L, Karpe F, Currie J M, Frayn K N, Fielding B A. Subcutaneous adipose tissue blood flow varies between superior and inferior levels of the anterior abdominal wall.  Int J Obes Relat Metab Disord. 2004;  28 228-233
• 24 Bulow J. Measurement of adipose tissue blood flow.  Methods Mol Biol. 2001;  155 281-293
• 25 Goossens G H, McQuaid S E, Dennis A L et al.. Angiotensin II: a major regulator of subcutaneous adipose tissue blood flow in humans.  J Physiol. 2006;  571 451-460
• 26 Hjortdal V E, Hauge E, Hansen E S. Differential effects of venous stasis and arterial insufficiency on tissue oxygenation in myocutaneous island flaps: an experimental study in pigs.  Plast Reconstr Surg. 1992;  89 521-529
• 27 Mahoney J L, Lista F R. Variations in flap blood flow and tissue PO2: a new technique for monitoring flap viability.  Ann Plast Surg. 1988;  20 43-47
• 28 Hofer S O, Timmenga E J, Christiano R, Bos K E. An intravascular oxygen tension monitoring device used in myocutaneous transplants: a preliminary report.  Microsurgery. 1993;  14 304-309