Association between case volume and hesitation to perform supraglottic airway insertion among emergency medical services personnel
Article information
Abstract
Objective
Advanced prehospital procedures performed by emergency medical services (EMS) clinicians are important for the care of emergency patients. Although procedural confidence is essential in urgent situations, its determinants remain unclear. This study examined whether individual case volume among EMS clinicians was associated with hesitation to perform supraglottic airway (SGA) insertion.
Methods
A nationwide cross-sectional survey of South Korean EMS personnel was conducted in August 2024. The questionnaire assessed demographic and occupational characteristics, procedural confidence, and unmet needs for specialized training. The primary outcome was self-reported hesitation to perform SGA insertion. Individual case volume was categorized as low-to-moderate (1–4 cases per 24 hours), high (5–8 cases), or very high (≥9 cases). Multivariable logistic regression was used to calculate adjusted odds ratios and 95% confidence intervals.
Results
Of 14,212 eligible EMS clinicians, 1,910 personnel voluntarily completed the survey, and 1,765 qualified participants were included in the final analysis. Overall, 26.9% of participants reported hesitation to perform SGA insertion. Hesitation was not significantly associated with individual case volume; compared with the low-to-moderate group, the adjusted odds ratios were 0.95 (95% confidence interval, 0.72–1.25) for the high-volume group and 0.88 (95% confidence interval, 0.68–1.13) for the very high-volume group.
Conclusion
Individual case volume was not associated with hesitation to perform SGA insertion. These findings suggest that confidence in advanced procedures may not be determined by field exposure alone.
INTRODUCTION
The prehospital phase of emergency medical care plays a critical role in patient survival and clinical outcomes [1]. Emergency medical services (EMS) clinicians provide on-site assessment, triage, and treatment and are therefore essential to public health [2,3]. Previous studies have consistently shown that patients treated by well-trained EMS clinicians have better clinical outcomes, particularly in critical conditions such as severe trauma and cardiac arrest [4,5]. Advanced prehospital procedures, including advanced airway management and intravenous (IV) drug administration, have also been associated with improved outcomes in emergency patients [6,7]. Studies of other healthcare professionals, including physicians and nurses, have shown that confidence is related to procedural performance [8-10]. Even in hospital settings, clinicians with greater case experience tend to report higher procedural confidence [11,12]. These findings suggest that ongoing clinical experience may help build both technical skills and self-confidence. Assessing procedural confidence among EMS clinicians and identifying its determinants may therefore help improve the success of advanced interventions in prehospital care.
Although the determinants of procedural confidence among EMS clinicians have not been clearly established, we hypothesized that field deployment frequency might be associated with hesitation to perform advanced procedures. Supraglottic airways (SGAs) have increasingly been adopted as alternatives to endotracheal intubation (ETI) because they are easier to insert, require shorter training, and have comparable effectiveness in prehospital settings [13-18]. This study evaluated the association between case volume and hesitation to perform SGA insertion among EMS clinicians using a nationwide survey.
METHODS
Study design and setting
This descriptive analysis was based on a nationwide cross-sectional survey of firefighters. South Korea has approximately 50 million residents and covers 100,210 km²; EMS are delivered through a centralized, government-run system. Under the National Fire Agency, 17 regional headquarters oversee approximately 240 fire stations and 14,000 emergency medical personnel. In the Korean EMS system, level-1 emergency medical technicians (EMTs) are roughly equivalent to advanced EMTs in the United States, whereas level-2 EMTs correspond to EMT-Basics. EMS clinicians in South Korea include nurses, level-1 and level-2 EMTs, and firefighters trained through a standardized 2-week emergency care program. Regional fire departments conduct routine training and assessments to maintain the quality of clinical and procedural skills [19].
In South Korea, EMS personnel certified to perform advanced prehospital procedures may carry out advanced life support interventions, including cardiopulmonary resuscitation (CPR) with an automated external defibrillator, airway management with SGA or ETI, IV line placement, and use of mechanical CPR devices. Certified personnel may also administer IV epinephrine under physician direction.
Survey
A nationwide survey was conducted to assess confidence and training needs related to advanced prehospital procedures and to examine how these factors were associated with field experience. The questionnaire was developed with reference to previous studies and expert consultation and comprised 60 items. A pilot test involving 30 active-duty EMS personnel was conducted to assess clarity and feasibility. On the basis of their feedback, redundant items were removed, and terminology was simplified for respondents across certification levels. Formal psychometric validation was not performed. The items were organized into six domains: demographic characteristics (12 items), airway management (13 items), patient assessment (12 items), circulatory support and drug administration (8 items), application and interpretation of advanced equipment (12 items), and program evaluation and open comments (3 items). Each confidence item was rated on a 5-point Likert scale (1=not confident at all, 5=very confident) (Supplementary Material).
The survey was administered online via Google Forms over a 2-week period in August 2024. The National Fire Agency officially disseminated the survey to regional fire headquarters across South Korea. Participants completed the survey voluntarily using personal smartphones or computers after providing consent regarding the study purpose, anonymity, and data use. Responses were collected as raw data and then cleaned, coded by item, and checked for missing values before analysis.
Study population
As of August 2024, the survey was limited to firefighters in South Korea who were actively engaged in EMS. The sample included EMS clinicians, including care providers and drivers; EMS administrative staff; emergency dispatch personnel; EMS instructors; and trainers at public safety experience centers. Substitute personnel and level-2 EMTs who were not certified to perform advanced procedures were excluded. The final analytic sample was restricted to respondents who were eligible to perform advanced prehospital procedures or complete procedure-related survey items.
Outcome measurement
The primary outcome was hesitation to perform SGA insertion. Hesitation was categorized as a binary variable. The survey item allowed multiple responses, including “No hesitation” and several hesitation-related reasons. Participants were coded as having hesitation if they selected any option other than “No hesitation.” Participants were coded as having no hesitation only if they selected “No hesitation” alone. Secondary outcomes examined the relationship between case volume and hesitation to perform other advanced prehospital procedures, including ETI, mass-casualty triage, prehospital stroke assessment, drug administration, electrocardiogram (ECG) interpretation, and end-tidal carbon dioxide monitoring.
Exposure and variables
To assess average case volume, participants were asked to choose one of five categories based on the number of EMS calls typically handled during a 24-hour shift: (1) 1–4, (2) 5–8, (3) 9–12, (4) 13–16, or (5) >16. The main independent variable was case volume, which was reclassified into three categories: low-to-moderate (1–4), high (5–8), and very high (≥9) [20-22]. The original item was categorical and consisted of five predefined response ranges. For analytical practicality, responses were consolidated into three broader groups. The 5–8-case range, which represented the median of the response distribution, was designated as the middle group. Given the relatively high EMS case volume in Korea, the highest-frequency group was defined as ≥9 cases.
Statistical analysis
Data were analyzed using SAS version 9.4 (SAS Institute Inc.). Primary variables were reclassified into categorical formats based on clinical relevance and investigator judgment. Descriptive statistics were used to summarize demographic characteristics and the frequency of advanced procedure performance. Group comparisons were performed using chi-square tests for categorical variables and Kruskal–Wallis tests for continuous variables. Binary logistic regression was used to examine the relationship between case volume and hesitation to perform advanced procedures, including SGA insertion. Multivariable logistic regression was performed after univariable analysis, with adjustment for covariates including sex, age, education level, rank, clinical experience, and EMS tenure. Statistical results were expressed as odds ratios (ORs) with 95% confidence intervals (CIs), and the significance threshold was set at P<0.05.
Ethics statement
This study was deemed exempt from ethical review by the Seoul National University Hospital Biomedical Research Institute because it was a secondary analysis of previously collected anonymous survey data (IRB No. 2505-048-1638).
RESULTS
Demographic findings
Of the 14,212 eligible EMS clinicians, 1,910 completed the survey, and 1,765 qualified participants were included in the analysis (Fig. 1). Participants were categorized into three case-volume groups: low-to-moderate (n=551, 31.2%), high (n=507, 28.7%), and very high (n=707, 40.1%). The proportion of participants who performed CPR ≤2 times per month was significantly lower in the very high-volume group than in the low-to-moderate group (61.4% vs. 95.1%), indicating more frequent CPR exposure among clinicians with higher case volumes (P<0.01) (Table 1).
Flowchart of emergency medical service (EMS) personnel selection for final enrollment.
Demographic and occupational characteristics, and frequency of EMS procedures according to case volume among EMS clinicians
Main analysis
Hesitation to perform SGA insertion was reported by 28.3% of participants in the low-to-moderate group, 27.0% in the high group, and 25.6% in the very high group (P=0.56) (Table 2). Multivariable logistic regression showed no significant association between case volume and hesitation to perform SGA insertion (adjusted OR for high vs. low-to-moderate, 0.95; 95% CI, 0.72–1.25; adjusted OR for very high vs. low-to-moderate, 0.88; 95% CI, 0.68–1.13) (Table 3).
Perceived deficiencies and procedural hesitation according to case volume among EMS clinicians
Multivariable logistic regression analysis of hesitation in performing advanced EMS procedures according to case volume
Hesitation regarding other advanced procedures, including ETI, mass-casualty triage, prehospital stroke assessment, ECG interpretation, and end-tidal carbon dioxide monitoring, also did not differ significantly among groups (P>0.05) (Table 2), and multivariable models showed no significant associations (Table 3).
Hesitation to perform IV drug administration was lower in the very high-volume group than in the low-to-moderate group (39.5% vs. 45.6%; P=0.04) (Table 2), and regression analysis showed reduced odds of hesitation (adjusted OR, 0.78; 95% CI, 0.62–0.98) (Table 3). Although slight changes in hesitation were observed for some tasks (mass-casualty triage: 61.7% vs. 60.1%; ECG interpretation: 67.5% vs. 69.6%; end-tidal carbon dioxide monitoring: 57.9% vs. 56.2%), these differences were not statistically significant in adjusted models (Table 3).
DISCUSSION
This study found no significant relationship between case volume and hesitation to perform SGA insertion among EMS clinicians. In contrast, IV drug administration showed a significant inverse association, with higher case volume associated with lower hesitation. These findings suggest that field exposure alone may not improve confidence in airway management, particularly for invasive procedures such as ETI and intermediate-level skills such as SGA insertion. For other procedures, including mass-casualty triage, ECG interpretation, and end-tidal carbon dioxide monitoring, no significant association with case volume was observed. Overall, repeated on-scene exposure may help build confidence in some frequently encountered procedures, whereas rarely performed skills may require additional educational interventions. Several mechanisms may explain these findings. First, case volume reflects the quantity of field exposure but does not necessarily reflect opportunities to perform specific procedures. EMS units with high transport volumes may prioritize a “scoop and run” approach, which can limit thorough assessment and the use of advanced procedures. In addition, the role of each EMS clinician at the scene may not be clearly defined; consequently, clinicians with lower confidence may have few opportunities to perform a given procedure despite higher case volume. This discrepancy is particularly relevant for infrequent interventions such as SGA insertion, for which increased deployment does not guarantee procedural exposure. General field experience alone may therefore be insufficient to reduce hesitation, underscoring the need for procedure-specific training strategies. Table 1 shows that even in the very high-volume group, the proportion of clinicians who performed ETI ≤2 times per month (96.2%) was similar to that in the low-volume group (99.8%). In contrast, procedures such as IV drug administration and prehospital stroke assessment varied substantially across case-volume groups, suggesting that frequent deployments do not necessarily provide adequate opportunities to perform rare, high-complexity procedures such as ETI. Second, complex invasive procedures require deliberate practice rather than passive exposure. Prior studies of laryngoscopic intubation training suggest that approximately 47 attempts may be required to achieve a 90% probability of competent performance [23]. This threshold is unlikely to be achieved through routine field exposure alone, which may explain why hesitation toward ETI remained high (approximately 90%) across all groups. Persistent hesitation may also reflect the invasive nature, technical complexity, and low prehospital frequency of ETI. In South Korea, ETI and SGA are currently recommended at a similar level in prehospital performance evaluations. This evaluation framework is based on evidence from a recent clinical trial [24]; as a result, EMS clinicians may have fewer incentives to choose more technically demanding procedures. Third, confidence development may depend on qualitative reinforcement rather than repetition alone. For example, IV drug administration may provide immediate positive feedback, such as rapid improvement in consciousness after glucose administration for hypoglycemia, which may reinforce clinician confidence. In contrast, SGA insertion provides limited direct feedback and is often performed under stressful, high-risk conditions, which may perpetuate hesitation even among experienced providers. Collectively, these observations suggest that procedure-specific experience, rather than the sheer number of deployments, may be the main determinant of confidence in advanced procedural skills.
The current findings both align with and diverge from prior research. They differ from some previous studies because total case volume, rather than procedure-specific exposure, was not associated with SGA hesitation in the present analysis. Hill et al. [25] found that Australian EMS clinicians had low confidence in out-of-hospital childbirth, even among experienced providers, suggesting that rare, high-risk interventions may elicit hesitation regardless of general experience. Similarly, Furin et al. [26] reported that more than half of Pennsylvania EMS clinicians lacked confidence in performing surgical airways, further emphasizing the gap between rare procedures and clinician confidence. In contrast, Yang et al. [12] found that greater procedural frequency was correlated with higher confidence in routine core skills among hospital nurses, which is consistent with our finding that hesitation regarding IV drug administration decreased as case volume increased.
Increasing deployment frequency alone is unlikely to reduce EMS clinicians’ hesitation to perform advanced procedures. Instead, structured educational programs and expanded procedural opportunities are needed. Simulation-based refresher training, hospital-based airway rotations, and standardized retraining protocols, as recommended by Ono et al. [27], could help address the experience gap for rarely performed skills. Our findings regarding IV drug administration further highlight the value of deliberate practice opportunities and feedback-rich learning environments. Future studies should evaluate whether these interventions improve clinician confidence and, ultimately, patient outcomes.
This study has several limitations. First, because of its cross-sectional design, causal inferences between case volume and procedural hesitation cannot be made; only associations at a single time point were examined. Second, hesitation was assessed using a self-administered questionnaire, which may be affected by respondent subjectivity and social desirability bias. In addition, although the survey instrument underwent pilot testing, formal psychometric validation was not performed, which may limit the reliability and interpretability of the responses. Third, only approximately 12% of EMS personnel nationwide voluntarily participated in the survey, raising the possibility of selection bias if respondents with greater interest or confidence in clinical procedures were more likely to participate. Fourth, case volume was categorized according to 24-hour duty shifts, which may not adequately represent cumulative long-term exposure or varied work conditions, and the measure did not account for qualitative aspects of exposure, such as the frequency of critically ill patients. Finally, residual confounding from unmeasured variables may have influenced the findings. Future studies should use validated instruments and more detailed measures of procedure-specific exposure to address these methodological limitations.
In conclusion, case volume was not significantly associated with hesitation to perform most advanced procedures, including SGA insertion, the primary outcome. These findings suggest that enhancing procedural confidence among EMS clinicians requires structured education and continuous practice rather than field experience alone.
Notes
FUNDING
None.
CONFLICT OF INTEREST
Sang Do Shin is an editorial board member of the journal but was not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflicts of interest relevant to this article were reported.
AUTHORS’ CONTRIBUTIONS
Conceptualization: SAY, KHK; Data curation: SAY; Formal analysis: SAY, KHK; Investigation: SAY, KHK; Methodology: YJP, KJH, KJS, SDS; Project administration: YJP, KJH, KJS; Resources: YJP, KJH, KJS, SDS; Supervision: KHK, YJP, KJH, KJS, SDS; Validation: YJP, KJH; Visualization: KHK; Writing–original draft: SAY, KHK; Writing–review & editing: SAY, KHK, YJP, KJH, KJS, SDS. All authors read and approved the final manuscript.
ACKNOWLEDGMENTS
We would like to acknowledge and thank the National Fire Agency and the Seoul Metropolitan Fire and Disaster Headquarters for enabling the research through provision of resources and human resource exchange collaborative program.
Supplementary Material
Supplementary materials can be found via https://doi.org/10.35616/jemsm.2025.00234