Alex Bukoski

Objective Measurement of Clinical Competency in Surgical Education Using Electrodermal Activity

OBJECTIVE Within the realm of surgical education, there is a need for objective means to determine surgical competence and resident readiness to operate independently. We propose a novel, objective method of assessing resident confidence and clinical competence based on measurement of electrodermal activity (EDA) during live surgical procedures. We hypothesized that with progressive training, EDA responses to the stress of performing surgery would exhibit decline, elucidating an objective correlate of clinical competence. DESIGN EDA was measured using galvanic skin response sensors worn by residents performing laparoscopic cholecystectomy on sequential live human patients over an 8-month period. Baseline, phasic (peak) and tonic EDA responses were measured as a fractional change from baseline. SETTING University of Missouri, Columbia, Missouri, an academic tertiary care facility. PARTICIPANTS Fourteen categorical general surgery residents and 5 faculty surgeons were voluntarily enrolled and participated through completion. RESULTS Tonic fractional change (FCTONIC) was highest in PGY3 residents compared with postgraduate year (PGY) 1 and 2 residents (7.199 vs. 2.100, p = 0.004, 95% CI: 8.58-1.61 and PGY4 and 5 residents (7.199 vs. 2.079, p = 0.002, 95% CI: 8.38-0.29). Phasic fractional change in EDA (FCPHASIC) exhibited a progressive decline across resident training levels, with PGY1 and 2 residents having the highest response, and faculty displaying the lowest FCPHASIC responses. Statistical differences were seen between FCPHASIC faculty and PGY4 and 5 (3.596 vs. 6.180, p = 0.004, 95% CI: 0.80-4.36), PGY4 and 5, and PGY3 (6.180 vs. 15.998, p = 0.003, 95% CI: 3.33-16.3), as well as among all residents and faculty (13.057 vs. 3.596, p = 0.004, 95% CI: 15.8-3.1). CONCLUSION Phasic EDA changes decrease with increasing clinical competence. For those participants with the lowest and highest levels of competence, tonic EDA changes are minimal. Tonic EDA changes follow an inverse-U shape with differing levels of clinical competence.

Recognition and Treatment of Nerve Agent Casualties: Evidence of Reduced Learner Engagement During Video-based Training

Changes in electrodermal activity (EDA) correlate with arousal and stress during stimulating experiences. We hypothesized that associations exist between short-term performance gains and changes in EDA. A total of 187 combat medics were randomly assigned to simulation (S), live tissue (L), or video (V) based training in the recognition and treatment of nerve agent casualties. Change in EDA from baseline to training was quantified for tonic and phasic responses and was categorized as positive (>+10%), no change (±10%), or negative (<-10%). Cognitive and psychomotor skills assessments were applied before and after the baseline/training period to quantify short-term performance changes. Statistically significant differences in both EDA arousal measures between training modalities (p < 0.001 with L > S ∼ V) were observed. Notably, larger proportions of trainees experienced negative changes in tonic (67%) and phasic (21%) EDA measures in the V group when compared to the L and S groups. Regardless of training modality, negative tonic and phasic EDA responses were associated with lower psychomotor performance gains and this finding approached statistical significance (tonic: p = 0.056, phasic: p = 0.08). No significant differences were noted in pre- to post-training cognitive performance between EDA response categories. As quantified by EDA response to training, reduced arousal was associated with lower short-term psychomotor, but not cognitive, performance gains.

Surgical resident technical skill self-evaluation: increased precision with training progression

BACKGROUND Surgical resident ability to accurately evaluate ones own skill level is an important part of educational growth. We aimed to determine if differences exist between self and observer technical skill evaluation of surgical residents performing a single procedure. MATERIALS AND METHODS We prospectively enrolled 14 categorical general surgery residents (six post-graduate year [PGY] 1-2, three PGY 3, and five PGY 4-5). Over a 6-month period, following each laparoscopic cholecystectomy, residents and seven faculty each completed the Objective Structured Assessment of Technical Skills (OSATS). Spearmans coefficient was calculated for three groups: senior (PGY 4-5), PGY3, and junior (PGY 1-2). Rho (ρ) values greater than 0.8 were considered well correlated. RESULTS Of the 125 paired assessments (resident-faculty each evaluating the same case), 58 were completed for senior residents, 54 for PGY3 residents, and 13 for junior residents. Using the mean from all OSATS categories, trainee self-evaluations correlated well to faculty (senior ρ 0.97, PGY3 ρ 0.9, junior ρ 0.9). When specific OSATS categories were analyzed, junior residents exhibited poor correlation in categories of respect for tissue (ρ -0.5), instrument handling (ρ 0.71), operative flow (ρ 0.41), use of assistants (ρ 0.05), procedural knowledge (ρ 0.32), and overall comfort with the procedure (ρ 0.73). PGY3 residents lacked correlation in two OSATS categories, operative flow (ρ 0.7) and procedural knowledge (ρ 0.2). Senior resident self-evaluations exhibited strong correlations to observers in all areas. CONCLUSIONS Surgical residents improve technical skill self-awareness with progressive training. Less-experienced trainees have a tendency to over-or-underestimate technical skill.

Perceptions of Simulator- and Live Tissue-Based Combat Casualty Care Training of Senior Special Operations Medics

The relative effectiveness of live tissue (LT)- and inanimate simulation (SIM)-based training of combat medics is the subject of intense debate. A structured interview was utilized to determine the training modality preferences and the perceived value of LT- and SIM-based combat casualty care training of 25 senior special operations medics. Participant demographics and training experience, Likert scale-based assessment of training modality value, selection of preferred training modality for 11 combat casualty care procedures, and 12 open-ended questions probing opinions of the limitations and benefits of LT- and SIM-based training were collected from this convenience sample. All participants indicated significant combat medic experience and training. Of the 11 procedures questioned, LT was identified as superior for seven with mixed responses for the remaining four. LT was consistently identified as an essential training modality with tactile sensation and the physiologic responses of animal models to injury and therapy as primary benefits. Across procedures, 100% of participants felt that LT should be used in combat casualty care training and 96% felt that SIM should also be utilized. Repeatability and accuracy of size/weight were identified as key benefits of SIM training. Respondents reported that capability, self-confidence, success, and resilience of the combat medic all benefitted from LT training. The overriding theme was the general superiority of LT with recognition of the unique and complementary benefits of SIM.

Case Difficulty, Postgraduate Year, and Resident Surgeon Stress: Effects on Operative Times

OBJECTIVE We aimed to evaluate resident operative times in relation to postgraduate year (PGY), case difficulty and resident stress while performing a single surgical procedure. DESIGN We prospectively examined operative times for 268 laparoscopic cholecystectomies, and analyzed relationships between PGY, case difficulty, and resident surgeon stress utilizing electrodermal activity. Each case operative times were divided into 3 separate time periods. Case Start and End times were recorded, as well as the time between the start of the operation and the time until the cystic structures were divided (Division). Case difficulty was determined by multiple trained observers with a high inter-rater concordance. SETTING University of Missouri, a tertiary academic medical institution. PARTICIPANTS All categorical general surgery residents at our institution. RESULTS For each operative time period examined during laparoscopic cholecystectomy, operative time increased, with each incremental increase in difficulty resulting in approximately 130% longer times. Minimal differences in operative times were seen between PGY levels, except during the easiest cases (Start-End times: 38.5 ± 10.4 minutes vs 34.2 ± 10.8 minutes vs 28.9 ± 10.9 minutes, p 0.002). Resident stress poorly correlated with operative times regardless of case difficulty (Pearson coefficient range 0.0-0.22). CONCLUSIONS Operative times are longer with increasing case difficulty. PGY level and resident surgeon stress appear to have minimal to no correlation with operative times, regardless of case difficulty.

Critical slowing in a Hodgkin-Huxley neuron near spiking threshold

As noted by Freeman [1], a quiescent neuron approaching spiking threshold exhibits a nonlinearly increasing sensitivity to stimulus. This growth of subthreshold susceptibility can be quantified by applying a linear multivariate Ornstein-Uhlenbeck analysis to the neuron equations, and this has been verified recently [2] for a reduced two-variable spiking model due to Wilson [3]. Here we generalize this stochastic analysis to the classical four-variable conductance-based Hodgkin-Huxley neuron with type-I excitability [4], perturbed by independent white noises entering the drive current and gating variables. We demonstrate critical slowing down—growth in amplitude simultaneous with decay in frequency of soma voltage fluctuations—as the neuron approaches firing threshold. We show that this behavior is a direct result of the interaction between the model’s eigenvalue structure and the noisy environment in which a biological neuron is presumed to function. Stochastic calculus results applied to this four-variable system predict fractional power-law scaling in the divergences for both voltage fluctuations (see Fig. ​Fig.1)1) and correlation time as the critical point of saddle-node annihilation is closely approached. Such divergences are expected to be universal characteristics for all type-I neuron models. If these critical fluctuations are communicated to neighboring neurons via ubiquitous electrical gap junctions, then subthreshold neuronal dynamics may play an important role in overall cortical dynamics. Figure 1 Subthreshold response to white-noise perturbation as a function of Idc stimulus current. Solid black curves show theoretical ±3 standard deviation limits for voltage excursions δV away from equilibrium and each vertical gray trace shows ...