Free Flap Monitoring Using Skin Temperature Strip Indicators: Adjunct to Clinical Examination

Abstract

Sir: Free tissue transfer procedures are performed with high levels of success today. Accurate postoperative flap monitoring is critical for favorable surgical outcome. Serial clinical surveillance by an experienced microsurgeon remains the standard of care for free flap monitoring. Unfortunately, this is neither practical nor always possible; therefore, additional medical caregivers are taught this art. In our practice, we have a dedicated hospital wing with experienced nurses monitoring the flaps in the postoperative setting. In most hospital environments, shift-changing nurses, residents, medical students, nurses’ aides, and even family members are educated about flap monitoring in an abbreviated manner. Morning rounds can be greeted with unpleasant surprises. To make free flap monitoring more reliable, various “technological advances” for flap monitoring have been developed to complement clinical evaluation. Technological tools available include laser Doppler imaging, fluorescein blue mapping, lactic acid elevation, photoplethysmography, differential thermometry, dermofluorometry, radioactive microspheres, electromagnetic flowmetry, and internal Doppler devices.1 Many of these techniques are impractical, unavailable, and expensive. Surface temperature recordings for flap monitoring have been reported to be successful.2,3 Electronic temperature probes are clinically available and require additional leads to be attached to the flap skin island and surrounding skin. Using this cumbersome technique, the patient is soon wrapped in a web of electrocardiographic and temperature probe leads. A simpler solution is the use of anesthesia skin temperature strip indicators (Sharn Anesthesia, Inc., Tampa, Fla.), which can be placed on both the patient’s flap skin island and native skin without much trouble (Fig. 1). These temperature strips detect temperature changes of 2ºC. Medical personnel can use this additional flap monitoring method along with clinical and Doppler examination. Our experience using temperature strips to monitor perforator flaps is similar to that in the 1979 report by Baudet et al. using infrared thermograms to monitor groin (known today as superficial inferior epigastric artery) free flaps.4 It is common to observe a 2ºC to 3ºC difference between flap and control temperatures in the early postoperative setting. However, an acute drop of 3ºC at the center of the skin island is indicative of arterial thrombosis, whereas a 1ºC to 2ºC uniform drop over of the flap is indicative of venous compromise. Temperature strips can detect these changes with effectiveness equal to that of electronic temperature monitoring.Fig. 1.: Temperature strip monitoring after deep inferior epigastric perforator microsurgical breast reconstruction.This adjunctive technique is simple and inexpensive ($1 per strip). We advocate that this technique complement but not replace traditional clinical and handheld Doppler examination. Despite 30 years of greater flap physiology understanding, flap monitoring continues to require competent human clinical judgment. Improved flap monitoring education for all medical personnel makes for restful evenings. Ernest S. Chiu, M.D. Andrew Altman, M.D. Tulane Health Sciences Center New Orleans, La. Robert J. Allen, Jr., B.S. Robert J. Allen, Sr., M.D. Center for Microsurgical Breast Reconstruction Charleston, S.C.