Monitoring the Surgeon, Not the Free Flap

The mental burden of surgeons during surgical practice has been a subject of great interest for a long time, but it was difficult to measure this concept until recently. We wanted to evaluate the mental stress of a surgeon during microsurgery, after performing similar studies on rhinoplasty and liposuction,[1] [2] with the aid of a recently popularized method, heart rate variability (HRV). HRV, utilizing periodic fluctuations of the heart rate to assess the relative contributions of the parasympathetic and sympathetic nervous systems, has considerable potential and is widely recognized as an important index of autonomic nervous system fluctuations in normal healthy individuals. Analysis of HRV is appropriate to reflect the sympathovagal balance as an output of the mental load of the surgeon.[3] [4] [5]

A 34-year-old, male, healthy plastic surgeon was monitored with a digital Holter recorder (Reynolds Pathfinder System) on two occasions between 10 a.m. and 8 p.m. during a unilateral breast reconstruction with a DIEP flap (in which the participant was the single surgeon) and during a routine office day without any surgery. The timing of each activity (flap dissection, anastomosis, etc.) was carefully documented during the operation. Heart rate and two indices of HRV (high frequency component, HF, as an indicator of parasympathetic activity and low-to-high frequency ratio, LF/HF, reflecting sympathetic activity) were analyzed and compared.

The operation started at 10:30 a.m. and ended at 7 p.m., including a 30-min lunch at 1 p.m. The effect of performing microsurgery on cardiac autonomic modulation of the operator was outstanding. Heart rate (66 ± 3 vs. 80 ± 6) and sympathetic activity (3.2 ± 0.8 vs. 4.6 ± 2.0) of the surgeon were consistently higher during each step of the DIEP when compared with office day values, and parasympathetic activity (23.5 ± 4.5 vs. 18.7 ± 6.2) was lower during surgery (Table [1]). Course of the measurements is given in Figure [1].

Table 1 Heart Rate, Parasympathetic and Sympathetic Activity Values (mean ± standard deviation) of the Surgeon in Office and During DIEP OFFICE DIEP Heart rate (bpm) 66 ± 3 80 ± 6 Parasympathetic activity (HF, nu) 23.5 ± 4.5 18.7 ± 6.2 Sympathetic activity (LF/HF) 3.2 ± 0.8 4.6 ± 2.0

Figure 1 The course of heart rate (HR), parasympathetic activity (PSA, measured as HF) and sympathetic activity (SA, measured as LF/HF) of the surgeon during DIEP and office day. I: dissection of the flap and the perforator. II: dissection of the internal mammary vessels and final steps of perforator dissection after lunch. III: preparation of the recipient and donor vessels for anastomosis. IV: vein anastomosis. V: artery anastomosis. VI: shaping of the flap.

Surgery, particularly more demanding microsurgery, creates a unique mental strain in its performers that other professions rarely bring forth. Surgeons are frequently compared with airline pilots and racing drivers in respect to heart rates. Occupants in both jobs have higher heart rates at particular times (landing and taking off, racing), but the periods are relatively shorter and less frequently experienced.[6] [7] [8] [9] On the countrary, surgery constitutes an important part of a surgeon's life as a continual practice, and surgeons are exposed to this stress almost every day.

The stress that we experience during surgery (in fact peaking all through microsurgery, as shown) is a purely mental variety. The surgeon does not usually have a chance to discharge energy through physical exercise after free flap surgery. There is convincing evidence that such metabolically or energetically not “consumed” stresses have negative long-term effects on human health, in such a manner that persistent psycho-physiologic activation has been identified as a risk factor for development of hypertension, cardiac arrhythmias, blood lipid disturbances, diabetes mellitus, and probably coronary heart disease.[10] [11] Nevertheless, according to the stress-strain concept, the adverse effects of increased psycho-physical stress can be attenuated by a reduction of stressor factors and by an improvement in working conditions.[8]

The only period where the measured parameters yielded similar results between the office and the surgery day was around 1 p.m. (see Fig. [1]), when the surgeon was having lunch on the surgery day. This finding further emphasizes the logic of two surgical teams for a particular free flap surgery - to share the burden and to avoid a sustained sympathetic hyperactivity.

This one case analysis establishes that sympathetic hyperactivity accompanies the surgeon during microsurgery as well, implying that performing microsurgery is associated with alterations in cardiac autonomic control. Such a situation is supposed to have a negative impact on performance, but this issue needs to be elucidated further by more comprehensive research.

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