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Fingerstall-type Tissue Oximetry Reduced Anxiety of Nurses in Postoperative Nursing Monitoring of Free Flaps

Tsuge, Itaru MD, PhD; Yamanaka, Hiroki MD, PhD; Katsube, Motoki MD, PhD; Sakamoto, Michiharu MD, PhD; Saito, Susumu MD, PhD; Morimoto, Naoki MD, PhD

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Plastic and Reconstructive Surgery - Global Open: December 2021 - Volume 9 - Issue 12 - p e3991
doi: 10.1097/GOX.0000000000003991



In the article “Fingerstall-type Tissue Oximetry Reduced Anxiety of Nurses in Postoperative Nursing Monitoring of Free Flaps,” published as e3991 in Plastic and Reconstructive Surgery Global Open on November 29, 2021, there was an error in the Supplemental Digital Content. The wrong file was initially included for SDC 1. The article has been updated online to reflect the correct figure file for SDC 1.

Plastic and Reconstructive Surgery – Global Open. 10(1):e4129, January 2022.


Question: We implemented monitoring with the fingerstall-type tissue oximeter Toccare, a noninvasive device that enables easy flap checking by simply touching the flap with a probe.

Findings: The average StO2 values in the DIEP and ALT flaps were 52.0% and 52.4%, respectively. According to the questionnaire for nurses about Toccare, 7% felt anxious, 62% felt slightly anxious, and 31% did not feel anxious.

Meaning: A numerical evaluation method with easy handling and clear doctor call criteria is essential for low-anxiety nursing monitoring.

Free flap reconstruction carries a risk of flap loss caused by obstruction of microsurgically anastomosed vessels in the postoperative course. Immediately noticing flap ischemia or congestion and performing early surgical intervention, such as thrombosis removal and re-anastomosis, can result in flap salvage. However, frequently checking the flap by assessing its color, capillary refill, and bleeding after pinprick is too laborious for resident doctors.1 Continuous tissue oximetry monitoring is becoming a reliable and labor-reducing method, but false positive alarms become frequent starting 24 hours postoperatively, being caused by factors as benign as a patient’s body movements.2

To mitigate these false alarms, we implemented a nursing monitoring protocol using handheld Doppler sonography once patients began to leave their bed the day after surgery, but nurses reported feeling extremely anxious about using this approach and demanded a clear-cut evaluation method. Therefore, we revised our postoperative protocol to one using a Toccare device (ASTEM Co., Ltd., Kawasaki, Japan), a fingerstall-type tissue oximeter that we found to be useful for the quick intraoperative evaluation of flap viability in 2017 and 2018.3,4 The Toccare has advantages in its noninvasiveness, compact size, and simplicity of measurement using numerical values, which matches postoperative flap monitoring to reduce anxiety of nurses. We herein report the changes with regard to nurses’ anxious feelings associated with the implementation of this new approach to patient monitoring.


This study was approved by the Kyoto University Medical Ethics Committee (R3087). Before the introduction of Toccare for postoperative monitoring, there was a period during which handheld Doppler sonography (ES-100V3; Hadeco Co., Ltd., Kawasaki, Japan) was used with marking the position to be checked from April to October 2020; however, nurses reported feeling anxious with this approach. We therefore collected information via an anonymous questionnaire to determine the reason for nurses’ discomfort with using Doppler monitoring (Table 1).

Table 1. - First and Second Questionnaires concerning Nursing Monitoring Using Doppler and Toccare
First Questionnaire for Nurses about Doppler Second Questionnaire for Nurses about Toccare
Nursing monitoring period 2020.04–2020.10 Nursing monitoring period 2020.12–2021.06
Questionnaire timing 2020.11 Questionnaire timing 2021.07
No. responses 36/38 (95%) No. responses 35/37 (95%)
Q1. Have you ever used Doppler for monitoring? Q1. Have you ever used Toccare for monitoring?
Yes 17/36 (47%) Yes 29/35 (83%)
No 19/36 (53%) No 6/35 (17%)
Q2. Do you feel anxious about the monitoring? Q2. Do you feel anxious about the monitoring?
Feel anxious 7/17 (41%) Feel anxious 2/29 (7%)
Feel slightly anxious 9/17 (53%) Feel slightly anxious 18/29 (62%)
Not feel anxious 1/17 (6%) Not feel anxious 9/29 (31%)
Q3. Why do you feel anxious? (free description) Q3. Why do you feel anxious? (free description)
Difficulty evaluating small beating sounds 7 Changes in the value depending on the probe position 8
Changes in the sound depending on the probe position 4 Difficulty selecting values that should be recorded 3
Difficulty judging whether or not to call a doctor 4 Difficulty of pressure to apply to the flap with a probe 2
Q4. Which method is better? (Question for both experienced nurses)
Toccare 16/18 (89%)
Handheld Doppler 2/18 (11%)

Toccare was then applied for postoperative free flap monitoring. The light weight of the module (0.1 kg), mobility (battery-powered), and the short sampling time (0.5 seconds) are useful features of this device; furthermore, it is approved for oral measurements (Fig. 1). Our protocol of nursing monitoring was as follows: continuous tissue oximetry OXY-2 (ViOptix Inc., Fremont, Calif.) was performed in all cases until 24 hours after surgery. Flap monitoring using a Toccare device was then performed every 4 hours from 24 to 100 hours postoperatively. Nurses who belonged to general wards measured the tissue oxygen saturation (StO2) values by touching the central part of flap with a Toccare probe. If the StO2 value was less than 40%, nurses summoned a doctor. The cut-off of 40% was decided based on our previous report that an StO2 of 41% coincided with the intraoperative indocyanine green fluorescence imaging border.3,4 (See Video [online], which shows an intraoperative flap evaluation using Toccare.)

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Fig. 1.:
Postoperative flap monitoring of an ALT flap for tongue cancer reconstruction using a fingerstall-type tissue oximeter, the Toccare.

The device was used for 7 months, from December 2020 to June 2021, and a second anonymous questionnaire was conducted in July 2021, with the results compared (Table 1). All the questionnaires were performed without any previous announcements.


Postoperative nursing monitoring with Toccare was performed for five cases of free deep inferior epigastric artery perforator (DIEP) flap and five cases of free anterolateral thigh (ALT) flap. All the 10 flap surgeries were performed by the first author, who is a microsurgeon with more than 10 years of experience. All DIEP flaps were for breast reconstruction after total mastectomy and skin-sparing mastectomy of breast cancer with zone 1 area positioning at the skin defect, and all ALT flaps were for head and neck reconstruction, such as intracranial cancer, maxillary cancer, pharyngeal fistula, ear canal cancer, and tongue cancer. All 10 cases had exposed skin flaps that required monitoring and showed no postoperative complications associated with the free flaps. (See figure, Supplemental Digital Content 1, which shows the positions of monitoring flaps in each of the 10 cases. (See table, Supplemental Digital Content 2, which shows the clinical information of 10 cases. The StO2 value in the DIEP flaps was 52.0% on average (Fig. 2, above), while that in the ALT flaps was 52.4% (Fig. 2, below). The cut-off for calling a doctor was set at less than 40% based on our previous study, but no cases with values of less than 40% were observed. (See figure, Supplemental Digital Content 1. (See figure, Supplemental Digital Content 2.

Fig. 2.:
The average StO2 values in five free DIEP flaps and five free ALT flaps were 52.0% (above) and 52.4% (below), respectively. Error bar: standard error.

According to the first questionnaire about handheld Doppler sonography, 41% felt anxious, 53% felt slightly anxious, and 6% did not feel anxious. According to the second questionnaire about Toccare, 7% felt anxious, 62% felt slightly anxious, and 31% did not feel anxious (Fig. 3). Toccare was preferred by 89% of nurses who had used both methods (Table 1).

Fig. 3.:
Toccare reduced nurses’ anxiety for the postoperative monitoring of free flaps.


The rate of take-back due to flap circulatory compromise is highest during the first day after surgery, dropping significantly by postoperative day 2 5; however, flap monitoring should be continued for 72 hours to improve the salvage rate by the early detection of vascular compromise.6 There is no universal consensus concerning the ideal flap monitoring method, although such a method would be harmless, rapid, reliable, objective and simple to interpret.7 Continuous tissue oximetry is useful, but the false positive rate increases significantly from 24 hours postoperatively due to probe malfunction/errors.2

To obtain the cooperation of nurses, the most important point is to reduce their anxiety and complaints concerning flap monitoring. Nursing education on free flap physiology and monitoring, such as capillary refill and venous congestion, improves confidence among nursing staff.8,9 We also have annual nursing education lectures; however, a complete education is not always possible in larger hospitals, and the skill level of nursing staff is often varied. We therefore felt that a numerically evaluated method with easy handling and clear criteria for summoning a doctor was essential for nursing monitoring. We considered Toccare had appropriate usability for the first postoperative 24 hours, too.

The present study indicated that Toccare reduced the anxiety of nurses, although 62% of nurses still felt slightly anxious, even with the Toccare protocol. We analyzed the years of nursing experience and found that nurses with fewer than 5 years of experience felt slightly anxious (11/12, 92%) or generally anxious (1/12, 8%) for Toccare. The anxiety questionnaire for traditional Doppler monitoring did not show the differences of nursing experience. Broyles et al reported that nurses with under 5 years of experience were less comfortable with flap monitoring than their more experienced colleagues, especially when newer technologies were employed.10

Nursing monitoring using Toccare has two limitations that should be mentioned: the need to monitor skin islands on the body surface and the need for more clinical cases of compromise to decide the StO2 value of alert. Also, limitations of this study are the relatively small number of flaps, the timing of questionnaires which may affect the behavior of nurses, and the differences of number of nurses included in the first and the second questionnaire.


Nursing monitoring using Toccare reduced the anxiety of nurses. We suspect that this device matches flap monitoring after patients get out of bed.


1. Patel UA, Hernandez D, Shnayder Y, et al. Free flap reconstruction monitoring techniques and frequency in the era of restricted resident work hours. JAMA Otolaryngol Head Neck Surg. 2017;143:803–809.
2. Tran PC, DeBrock W, Lester ME, et al. The false positive rate of transcutaneous tissue oximetry alarms in microvascular breast reconstruction rises after 24 hours. J Reconstr Microsurg. 2021;37:453–557.
3. Tsuge I, Enoshiri T, Saito S, et al. A quick evaluation of TRAM flap viability using fingerstall-type tissue oximetry. Plast Reconstr Surg Glob Open. 2017;5:e1494.
4. Tsuge I, Saito S. Determining transverse rectus abdominis musculo-cutaneous flap viability using fingerstall-type tissue oximetry as an alternative to indocyanine green fluorescence imaging: a case of a patient with iodine hypersensitivity. Plast Reconstr Surg Glob Open. 2018;6:e1966.
5. Baltodano PA, Schalet G, Rezak K, et al. Early discontinuation of breast free flap monitoring: a strategy driven by national data. Plast Reconstr Surg. 2020;146:258e–264e.
6. Chen KT, Mardini S, Chuang DC, et al. Timing of presentation of the first signs of vascular compromise dictates the salvage outcome of free flap transfers. Plast Reconstr Surg. 2007;120:187–195.
7. Kwasnicki RM, Noakes AJ, Banhidy N, et al. Quantifying the limitations of clinical and technology-based flap monitoring strategies using a systematic thematic analysis. Plast Reconstr Surg Glob Open. 2021;9:e3663.
8. Kleban SR, Ogley SC, MacDavid JC, et al. Nursing monitoring of microsurgical free flaps: identifying and addressing knowledge gaps. J Reconstr Microsurg. 2020;36:673–679.
9. Khan MA, Mohan A, Ahmed W, et al. Nursing monitoring and management of free and pedicled flaps—outcomes of teaching sessions on flap care. Plast Surg Nurs. 2010;30:213–6; quiz 217.
10. Broyles JM, Smith M, Coon D, et al. Assessment of nursing deficiencies in the postoperative care of microsurgical patients. J Reconstr Microsurg. 2016;32:615–624.

Supplemental Digital Content

Copyright © 2021 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.