Examining the Impact of Time Pressure in Regional Anesthesia: A Prospective Randomized Simulation-Based Study

Increasing surgical volumes and the ongoing anesthesia workforce shortage have intensified productivity demands in operating rooms, exposing anesthesia teams to growing production and time pressures.1 Production pressure has been associated with unsafe practices, and stress may lead to provider- or system-related lapses that threaten patient safety, primarily based on qualitative reports and surveys.2–4 Ultrasound-guided regional anesthesia (UGRA) requires strict adherence to safety-critical procedural steps, including appropriate monitoring, dose selection, and injection technique, which may be vulnerable to time constraints.5–8 Despite frequent reports of time pressure in anesthetic practice, quantitative evidence evaluating its effect on patient safety remains limited. We aimed to assess whether standardized time pressure influences safety-related performance and cognitive workload during UGRA in an in-situ simulation context. METHODS We conducted a prospective, randomized, single blind in-situ simulation study at Maisonneuve-Rosemont Hospital (Université de Montréal), between April and May 2021, following institutional ethics approval and prospective registration (ClinicalTrials.gov NCT04846660). This article adheres to applicable Consolidated Standards of Reporting Trials (CONSORT) guidelines. Participants included anesthesiology residents and attending anesthesiologists who had independently performed at least 10 ultrasound-guided peripheral nerve blocks, including a minimum of five infraclavicular blocks; the only exclusion criterion was refusal to participate. Participants were informed that the study involved a simulation-based regional anesthesia task; however, the specific research focus on time pressure was not disclosed to avoid influencing participant behavior. Participants were randomized to a time pressure group (TPG) or a control group (CG). All participants performed a single-injection ultrasound-guided infraclavicular block using a regional anesthesia task trainer positioned on a standardized patient. In the TPG, four standardized event-based prompts were delivered at predefined key moments of the scenario (Supplemental Digital Content, Supplemental Figure 1, https://links.lww.com/AA/F791), based on previously described sources of operating room pressure.3 Control participants completed the same scenario without time pressure. Procedural performance was assessed using the validated Regional Anesthesia Procedural Skills (RAPS) assessment tool, incorporating a procedural checklist, global rating scale, and pass/fail judgment.9 Items related to neurostimulation and catheter placement were excluded. Three regional anesthesia experts independently reviewed synchronized dual-view video recordings (procedural field and ultrasound screen) and resolved discrepancies by consensus (Figure). The primary outcome was the RAPS score as an indirect measure of patient safety.Figure.: Dual camera setup.Secondary outcomes included task completion time and cognitive workload, assessed using the National Aeronautics and Space Administration Task Load Index (NASA-TLX) (Supplemental Digital Content, Supplemental Figure 2, https://links.lww.com/AA/F792). Perceived realism was rated using a Likert scale. Group comparisons were performed using unpaired t tests or Mann–Whitney U tests as appropriate, with statistical significance defined as P ≤ .05. The effect size (r) was calculated to describe the magnitude of the association between the intervention and its impact within each group. Effect size (r) values of approximately 0.1, 0.3, and 0.5 are conventionally interpreted as small, medium, and large, respectively. Standardized mean differences (Cohen’s d) follow a similar interpretation, with thresholds of 0.2 (small), 0.5 (medium), and 0.8 (large). Given the absence of prior data to inform an a priori power calculation, a convenience sample based on the number of eligible residents and attending anesthesiologists at the study institution was used. RESULTS Thirty-nine participants were enrolled and randomized; 36 were included in the primary analysis (19 TPG, 17 CG). Three participants were excluded because of loss of ultrasound imaging related to participant positioning or incomplete video recordings. Participants comprised 58% anesthesiology residents and 42% attending anesthesiologists, with balanced distribution between groups. RAPS scores were comparable between the two groups: TPG 74.7 (12.3) vs CG 76.3 (14.6); unpaired t test, P = .719. The RAPS score showed a very small effect (r = 0.06, d = 0.13), indicating comparable performance between groups (Table). Table. - Primary and Secondary Outcomes by Group Outcome Measure TPG CG Statistical test P value Effect size (r) Standardized difference (Cohen’s d) Primary outcome RAPS score, mean (SD) 74.7 (12.3) 76.3 (14.6) Unpaired t test, t = 0.363, df = 34 .719 0.06 0.13 Secondary outcomes Cognitive workload (NASA-TLX), mean (SD) 52.4 (13.3) 38.4 (16.7) Unpaired t test, t = 2.801, df = 35 .008 0.43 0.95 Task completion time (s), mean (SD) 550 (230) 567 (278) Unpaired t test, t = 0.202, df = 35 .841 0.03 0.07 Perceived realism, median [IQR] 4 [4–4.75] 4.5 [4–5] Mann–Whitney U = 133.5 .154 0.15 0.30 Values are expressed as mean (SD) or median [IQR], as appropriate. Effect sizes (r) are interpreted as small (~0.1), medium (~0.3), and large (~0.5). Cohen’s d values of 0.2, 0.5, and 0.8 correspond to similar thresholds.Abbreviations: CG, control group; df, degrees of freedom; IQR, interquartile range; NASA-TLX, National Aeronautics and Space Administration Task Load Index; RAPS, Regional Anesthesia Procedural Skills assessment tool; SD, standard deviation; TPG, time pressure group. The cognitive workload, as measured by the NASA-TLX, was significantly higher in the TPG than in the CG (52.4 [13.3] vs 38.4 [16.7], unpaired t test, P = .008). Task completion time did not differ significantly between groups (TPG 550 [230] seconds versus CG 567 [278] seconds; unpaired t test, P = .841). Participants reported a similar level of perceived realism between the two groups (TPG 4 [4–4.75] vs CG 4.5 [4–5]; Mann–Whitney test, P = .154). The cognitive workload (NASA-TLX) demonstrated a large effect (r = 0.43, d = 0.95), suggesting a substantially higher perceived workload under time pressure. The task completion time difference represented a negligible effect (r = 0.03, d = 0.07). The perceived realism ratings showed no meaningful difference between groups (r = 0.15, d = 0.30) (Table). DISCUSSION In this randomized simulation study, standardized time pressure applied at predefined key moments of the scenario significantly increased cognitive workload during UGRA without impairing procedural performance or safety-related behaviors. These findings suggest that anesthesiologists and trainees may preserve technical performance under time pressure, albeit at the cost of increased mental demand. The absence of measurable performance degradation contrasts with qualitative reports linking time pressure to unsafe anesthetic practices.2–4 This discrepancy may be explained by the moderate cognitive complexity of the simulated task, the timing of time pressure interventions, or by participants’ expertise. Importantly, increased cognitive load in the absence of overt performance decline may still have implications for clinician fatigue, adaptability, and vulnerability to error during more complex or prolonged clinical situations. Methodological strengths include partial deception to minimize behavioral bias, in-situ simulation to enhance realism, and expert video-based assessment using a validated procedural tool.10 The methodological strength of our study is further supported by the dual camera setup capturing both the procedural field and the ultrasound view, providing a comprehensive and innovative evaluation framework. Limitations include the indirect measurement of patient safety and the simulation setting, which may not fully replicate real operating room consequences. Future studies should evaluate higher cognitive-load tasks and real clinical environments to better define the safety implications of time pressure in anesthesiology. In conclusion, exposure to time pressure at predefined key moments of the simulated procedure increased cognitive workload without compromising procedural performance during simulated ultrasound-guided infraclavicular block placement. These findings highlight cognitive burden as a relevant safety outcome and support further investigation of environmental stressors and cumulative system-related demands in perioperative care. DISCLOSURES Conflicts of Interest: None. Funding: None. This manuscript was handled by: Zeev Kain, MD, MBA.