Association of Level 3 Personal Protective Equipment With Intubation Success in the Emergency Department

ABSTRACT

Introduction

Tracheal intubation is an aerosol‐generating procedure that poses a high risk of infection for healthcare workers. While Level 3 personal protective equipment (PPE) is recommended, its effect on procedural performance remains uncertain. The objective of this study was to evaluate the association among Level 3 PPE use, first‐pass success, and adverse events during emergency department (ED) intubation.

Methods

We analyzed data from the Japanese Emergency Airway Network‐V, a multicenter prospective registry of 12 EDs in Japan. Adult patients, aged ≥ 18 years, who underwent emergency intubation between 2020 and 2022 were included. Level 3 PPE included disposable gloves, fluid‐repellent gowns or coveralls, filtering face piece 3 respirators, and eye protection. The primary outcome was first‐pass success, while secondary outcomes included major and minor adverse events, including hypotension, hypoxemia, cardiac arrest, and airway injury. Logistic regression with stabilized inverse probability of treatment weighting was performed to adjust for confounding variables.

Results

Of the 2431 patients, 1159 (47.7%) were intubated with Level 3 PPE. The unadjusted first‐pass success rate was higher with PPE (83.4% vs. 79.6%; p = 0.02); however, adjusted first‐pass success did not differ significantly (risk difference−0.4%, 95% CI–6.3 to 5.5; p = 0.88). After adjustment, major (0.8%, 95% CI–7.1 to 8.7) and minor (0.5%, 95% CI–2.2 to 3.2) adverse events showed no significant differences.

Conclusions

The use of Level 3 PPE was not associated with decreased success or increased adverse events, supporting its safe use during high‐risk procedures.

Level 3 PPE did not reduce first‐pass intubation success or increase adverse events among 2431 adults undergoing emergency airway management across 12 Japanese EDs. These findings support the safe use of Level 3 PPE during high‐risk aerosol‐generating procedures.

1. Introduction

Tracheal intubation, a high‐risk, aerosol‐generating procedure, posed a substantial infection risk to healthcare workers during the coronavirus disease 2019 (COVID‐19) pandemic. A systematic review reported that aerosol‐generating procedures, including tracheal intubation, increased the likelihood of infection among healthcare personnel by more than sixfold [1]. Accordingly, international guidelines have recommended the use of personal protective equipment (PPE) when treating patients with suspected or confirmed COVID‐19 [2]. However, the use of PPE may restrict vision, limit manual dexterity, and hinder communication, potentially increasing the technical difficulty of the procedure. Simulation studies have shown that PPE may lower the first‐pass success rate of tracheal intubation [3, 4, 5]. However, most of these studies were based on manikin or cadaver models, and clinical evidence under real‐world conditions remains scarce. Therefore, the objective of this study was to evaluate the impact of PPE use on first‐pass success and adverse events during tracheal intubation in the emergency department (ED), using multicenter prospective clinical data.

2. Methods

2.1. Study Design and Setting

This was a secondary analysis using data from the Japanese Emergency Airway Network‐V (JEAN‐V), a multicenter prospective observational study conducted at 13 hospitals across Japan [6, 7]. All ED patients intubated after April 2020 were registered regardless of age, indication, or arrest status. Among the participating institutions, 10 were tertiary emergency medical centers. All hospitals operated emergency medicine residency programs, and tracheal intubation was performed by emergency medicine residents, attending emergency physicians, physicians from other specialties, or transitional‐year residents (postgraduate year 1 or 2) under supervision.

2.2. Participants

Eligible participants were adult patients (aged ≥ 18 years) who underwent tracheal intubation in the ED between April 2020 and March 2022. Exclusion criteria were age < 18 years, implausible body mass index (BMI) values, unknown use of a video laryngoscope (VL), surgical cricothyrotomy, unknown intubator identity, and missing data regarding PPE use (Figure 1).

FIGURE 1.

Patient flow‐chart. Level 3 personal protective equipment (PPE) was defined according to the UK Health Security Agency as PPE consisting of disposable gloves, fluid‐repellent coveralls or a long‐sleeved apron/gown, an FFP3 respirator or powered respirator hood, and eye protection or a face shield.

2.3. Data Collection and Processing

After each intubation procedure, the operator completed a standardized data collection form. This form included basic patient information (age, sex, height, weight, and modified LEMON score), primary indications for intubation, intubation techniques, medications administered, intubation specialty, success or failure of each attempt, vital signs, and adverse events. BMI was calculated based on height and weight; obesity was defined as ≥ 30 kg/m² [8]. Compliance with the data forms was monitored. When data collection forms were missing, postprocedure interviews with the relevant physicians were conducted, and patients' medical records were reviewed to obtain details regarding airway management.

2.4. Primary Exposure and Outcomes

Primary exposure was the use of Level 3 PPE, defined as the simultaneous use of disposable gloves, a fluid‐repellent coverall or gown, a filtering face piece 3 (FFP3) respirator (or powered respirator hood), and eye protection [9]. Patients who did not wear all four components were assigned to the non‐Level 3 PPE group. The primary outcome was first‐pass success of tracheal intubation. Secondary outcomes included the occurrence of major and minor adverse events. Major adverse events were defined as hypotension (systolic blood pressure < 90 mmHg), hypoxemia (pulse oximetry saturation < 90%), delayed esophageal intubation, cardiac arrest, death, and dysrhythmia. Minor adverse events were defined as early recognition of esophageal intubation, endobronchial intubation, dental or lip trauma, regurgitation, and airway trauma [10].

2.5. Statistical Analysis

First, we compared patient characteristics and intubation‐related variables between the Level 3 PPE and non‐Level 3 PPE groups. Continuous variables were analyzed using the Mann–Whitney U test, and categorical variables were compared using the chi‐squared (χ²) test.

For the primary analysis, we constructed a logistic regression model using a stabilized inverse probability of treatment weighting (sIPTW) based on propensity scores to evaluate the association between Level 3 PPE use and first‐pass intubation success. To account for clustering within facilities, we estimated the standard errors using cluster‐robust standard errors. Propensity scores were calculated using a logistic regression model including the following covariates: age, sex, indication for intubation, suspected COVID‐19, obesity (BMI ≥ 30), predicted intubation difficulty (modified LEMON score), use of VL, use of rapid sequence intubation (RSI), and intubator category [11, 12]. sIPTW weights were stabilized using the marginal probabilities of the treatment assignment. Covariate balance after weighting was assessed using standardized mean differences, with values < 10% considered indicative of adequate balance.

Subgroup analyses were performed based on intubation device (VL vs. direct laryngoscope [DL]), RSI use (yes vs. no), intubator category (transitional‐year resident, emergency medicine resident, emergency physician, and other specialties), and study year (2020, 2021, and 2022).

Data analyses were conducted using Stata/BE 18.0 (StataCorp, College Station, TX, USA). A two‐tailed p‐value of < 0.05 was considered statistically significant.

3. Results

3.1. Patient Characteristics

During the study period, the JEAN‐V study recorded 2671 patients who underwent tracheal intubation in the ED (capture rate, 97.5%) (Figure 1). Of these, 2431 patients were eligible for the current analysis after excluding 65 patients aged < 18 years, 24 with implausible BMI values, 1 with unknown use of a VL, 13 who underwent surgical cricothyrotomy, 3 with missing intubator information, and 134 with missing PPE data.

Patient characteristics and airway management are presented in Table 1. The median age of patients was 70 years (interquartile range, 56–81 years), and 64.7% of the patients were male. The primary indications for intubation were cardiac arrest (47.7%), respiratory failure (21.8%), altered mental status (18.0%), and shock (7.8%). VLs were used in 74.9% of cases, and RSI was performed in 41.5% of cases. The first‐pass intubation success rate was 81.4%. Major adverse events occurred in 14.2% of patients, with hypoxemia identified as the most common. Conversely, minor adverse events occurred in 4.6% of patients.

TABLE 1.

Characteristics of the patients at baseline and airway management.

	Overall	With Level 3 PPE	Non‐Level 3 PPE	p
	n = 2431	n = 1159 (48)	n = 1272 (52)
Age (year), median (IQR)	70 (56–81)	70 (56–81)	71 (57–81)	0.17
Male sex	1573 (64.7)	765 (66.0)	808 (63.5)	0.20
Obesity (BMI ≥ 30)	193 (7.9)	111 (9.6)	82 (6.4)	0.01
Suspected COVID‐19	1554 (63.9)	946 (81.6)	608 (47.8)	< 0.001
Indication for intubation
Cardiac arrest	1160 (47.7)	498 (43.0)	662 (52.0)	< 0.001
Respiratory failure	529 (21.8)	344 (29.7)	185 (14.5)
Shock	190 (7.8)	80 (6.9)	110 (8.6)
Altered consciousness	437 (18.0)	183 (15.8)	254 (20.0)
Procedure	41 (1.7)	18 (1.6)	23 (2.0)
Others	74 (3.0)	36 (3.1)	38 (3.0)
Modified LEMON score ≥ 1	828 (34.1)	319 (27.5)	509 (40.0)	< 0.001
Use of video laryngoscope a	1820 (74.9)	971 (83.8)	849 (66.7)	< 0.001
Rapid sequence intubation	1010 (41.5)	568 (49.0)	442 (34.7)	< 0.001
Specialty of intubator				< 0.001
Transitional‐year resident b	454 (18.7)	196 (16.9)	258 (20.3)
Emergency medicine resident	1095 (45.0)	589 (50.8)	506 (39.8)
Emergency physician	667 (27.4)	279 (24.1)	388 (30.5)
Other specialties	2195 (8.8)	95 (8.2)	120 (9.4)
PPE
Disposable gloves	2419 (99.5)	1159 (100)	1260 (99.1)	< 0.001
Fluid‐repellent coveralls or gown	1334 (55.3)	1159 (100)	185 (14.5)	< 0.001
FFP3 respirator	1759 (72.4)	1159 (100)	600 (47.2)	< 0.001
Eye protection	2014 (82.8)	1159 (100)	855 (67.2)	< 0.001
First‐pass success rate	1980 (81.4)	967 (83.4)	1013 (79.6)	0.016
Major adverse events	346 (14.2)	214 (18.5)	132 (10.4)	< 0.001
Minor adverse events	113 (4.6)	54 (4.7)	59 (4.6)	1.0

Note: Data were presented as unweighted number (percentage) of patients unless otherwise indicated.

Abbreviations: BMI, body mass index; COVID‐19, coronavirus disease 2019; IQR, interquartile range; PPE, personal protective equipment.

^a Video laryngoscopes used included CMAC, Airway Scope, Glidescope, and McGrath.

^b Defined as postgraduate years 1 or 2.

Of the 2431 patients, 1159 (48.0%) underwent tracheal intubation with Level 3 PPE and 1272 (52.0%) did not. Patients intubated with Level 3 PPE had higher proportions of suspected COVID‐19, obesity, and respiratory failure. Conversely, a modified LEMON score ≥ 1 was higher in the non‐Level 3 PPE group. VL use, RSI, and intubation by emergency medicine residents were more frequent in the Level 3 PPE group.

The use of all individual components of Level 3 PPE (disposable gloves, fluid‐repellent coveralls or gowns, FFP3 respirators, and eye protection) was significantly more frequent in the Level 3 PPE group.

3.2. Associations Between Level 3 PPE and First‐Pass Intubation Success and Adverse Events

The first‐pass success rate was higher in the Level 3 PPE group than in the non‐Level 3 PPE group (83.4% vs. 79.6%; p = 0.02). However, after adjustment using sIPTW, the risk difference (RD) was −0.40% (95% CI, −6.3 to 5.5; p = 0.88) (Figure 2).

FIGURE 2.

Unadjusted and adjusted associations of Level 3 PPE use with first‐pass success rate and adverse events in adults requiring tracheal intubation. Abbreviations: CI, confidence interval; PE, personal protective equipment. Unadjusted and adjusted risk difference models using stabilized inverse probability of treatment weighting (sIPTW) with cluster‐robust standard errors were employed to account for interhospital clustering effects. The covariates used for adjustment included age, sex, indication for intubation, suspected COVID‐19, obesity (BMI ≥ 30), intubation difficulty (modified LEMON score), use of video laryngoscope, use of RSI, and training level of the intubator. § Adjusted for age, sex, indication for intubation, suspected COVID‐19, obesity (BMI ≥ 30), predicted intubation difficulty (modified LEMON score), use of video laryngoscope, use of rapid sequence intubation (RSI), and intubator category, using sIPTW with cluster‐robust standard errors. Defined as hypotension (systolic blood pressure < 90 mmHg), hypoxemia (pulse oximetry saturation < 90%), esophageal intubation with delayed recognition, cardiac arrest, death, and dysrhythmia. ‖ Defined as esophageal intubation with early recognition, endobronchial intubation, dental or lip trauma, regurgitation, and airway trauma.

Similarly, although the rate of major adverse events was higher in the Level 3 PPE group than in the non‐Level 3 PPE group (18.5% vs. 10.4%; p < 0.001), the adjusted RD was 0.8% (95% CI, −7.1 to 8.7; p = 0.83), indicating no statistically significant difference.

For minor adverse events, the non‐Level 3 PPE group showed a slightly higher incidence (4.7% vs. 4.6%; p = 1.0), but the adjusted RD was 0.5% (95% CI, −2.2 to 3.2; p = 0.70), which was not statistically significant.

3.3. Subgroup Analysis

In all subgroups, Level 3 PPE use was not significantly associated with first‐pass intubation success. In the year‐stratified analyses for 2020, 2021, and 2022, a significantly higher first‐pass success rate was observed in the Level 3 PPE group only in 2020 (RD, 11.3%; 95% CI, 0.4% to 22.0%; p = 0.04), whereas no statistically significant differences were detected between 2021 and 2022 (Table 2).

TABLE 2.

Association between Level 3 PPE use and first‐attempt success rate. (Subgroup analysis).

First‐pass success	With Leve 3 PPE n (%)	Non‐Level 3 PPE n (%)	Unadjusted risk difference n (%), 95% CI	p	Adjusted risk difference n (%), 95% CI	p
Specialty
Transitional‐year resident a	70.9	60.5	10.4 (1.7 to 19.2)	0.02	6.3 (−6.3–18.8)	0.29
Emergency medicine resident	87.9	85.6	2.3 (1.7 to 6.4)	0.25	−0.6 (−3.8 to 2.6)	0.71
Emergency physician	86.7	86.9	−0.2 (−5.3 to 5.1)	0.97	−4.4 (−11.8 to 2.9)	0.21
Other specialties	71.6	72.5	−0.9 (−13 to 11.2)	0.88	0.03 (−16.7 to 16.8)	1.0
Devices
Video laryngoscope	84.9	83.2	1.7 (−5.1 to 3.7)	0.32	−0.2 (−5.4 to 5.0)	0.95
Direct laryngoscope	76.1	72.6	3.5 (−10.9 to 3.9)	0.37	0.03 (−13 to 13.1)	1.0
Methods
RSI	89.1	84.8	4.2 (0.03 to 8.5)	0.05	3.1 (−3.7 to 10.0)	0.33
Non‐RSI	78.0	76.9	1.1 (−3.3 to 5.5)	0.61	−2.5 (−10.8 to 5.8)	0.52
Year
2020	85.0	74.7	10.3 (4.5 to 16.2)	< 0.001	11.3 (0.4 to 22.0)	0.04
2021	82.8	81.1	1.7 (−2.3 to 5.8)	0.40	−3.3 (−8.9 to 2.3)	0.23
2022	81.8	82.8	−1.0 (−9.2 to 7.2)	0.80	0.5 (−8.8 to 9.5)	0.93

Note: Data were presented as unweighted number (percentage) of patients unless otherwise indicated.

Abbreviations: PPE, personal protective equipment; RSI, rapid sequence intubation.

^a Defined as postgraduate years 1 or 2.

4. Discussion

In this study, we found no significant association between Level 3 PPE use and first‐pass success, major adverse events, or minor adverse events. These findings remained consistent after stratification by the intubation device type (VL vs. DL), RSI use, and intubator category (transitional‐year resident, emergency medicine resident, emergency physician, and other specialties). Previous research has often considered a ≥ 5.0% difference in first‐pass success to be clinically meaningful [13, 14]. However, in our study, the adjusted RDs for all outcomes were below this threshold, suggesting that the differences were both statistically and clinically insignificant.

Most previous studies have been simulation‐based and have suggested that PPE use may reduce first‐pass success [3, 4, 5]. For example, in a cadaver model study, the first‐pass success rate was lower in the PPE group than in the standard uniform group (72.0% vs. 83.0%) [3]. Likewise, in a study involving 19 emergency medicine residents and emergency medicine service personnel, the first‐pass success rate was significantly lower in the PPE group than in the non‐PPE group (58.0% vs. 96.0%; p < 0.001) [4]. Conversely, limited real‐world data have reported no clear reduction in success rates with PPE use [9], and our findings are consistent with this evidence.

Several potential mechanisms may explain the success and complication rates observed between the PPE and non‐PPE groups.

First, the COVID‐19 pandemic has prompted the introduction of simulation‐based training for airway management while wearing PPE in many institutions, which may have mitigated its potential negative impact. Simulation‐based training was shown to improve team performance, knowledge, and preparedness in managing patients with COVID‐19 [15, 16, 17]. These educational benefits can translate into improved clinical performance. Intubations performed by anesthesiologists are reportedly less affected by PPE than those performed by nonanesthesiologists (relative risk [RR] 1.0 [0.98–1.03] vs. RR 1.05 [1.0–1.1]) [18]. Our subgroup analyses by intubator category revealed no significant effects of PPE use (Table 2). Notably, one study reported marked improvements in simulation‐based training assessment scores, especially among nonanesthesiologists and residents, suggesting that such training may contribute to skill enhancement in these groups [17].

Second, unmeasured clinical factors may have contributed to this finding. Since the onset of COVID‐19, practices such as preintubation briefings, role allocation, standardization of PPE donning, targeted supervision by senior physicians, and environmental optimization during intubation (e.g., prepositioning of equipment and assistants) have improved, likely minimizing the potential limitations imposed by PPE.

Collectively, this study provides important real‐world evidence from the largest prospective dataset to date, offering insights that differ from those of simulation‐based studies. Building on this foundation, future research should investigate how PPE use influences procedural performance across diverse healthcare systems and how training and system‐level preparedness can be further optimized for future infectious disease outbreaks.

4.1. Potential Limitations

This study has several limitations. First, as this was a multicenter, prospective, observational study, data on tracheal intubation were self‐reported by healthcare providers, introducing the possibility of reporting bias. As in previous JEAN studies, standardized definitions and data collection forms were used, likely minimizing bias [19]. The high capture rate (97.0%) of our multicenter dataset reflects the actual patient population and enhances generalizability. Second, PPE use may have varied by institution and period, and residual confounding from unmeasured factors (e.g., intubator skill, team composition) may remain despite statistical adjustment. Third, we did not collect data on intubation duration or direct measures of procedural difficulty. Finally, our study was conducted primarily in university and core hospitals in Japan, potentially limiting its external validity to other healthcare systems or prehospital settings.

5. Conclusions

Level 3 PPE use was not associated with significant differences in first‐pass success or adverse event rates during tracheal intubation in the ED. For clinicians, these findings indicate that tracheal intubation, a high‐risk, aerosol‐generating procedure, can be safely performed while wearing PPE without compromising procedural performance, supporting current infection control guidelines. Our study provides real‐world data on airway management under PPE conditions and may serve as a foundation for future research on pandemic preparedness and procedural safety.

Ethics Statement

The institutional review boards of all participating institutions approved this study (approval number: 21‐H‐4). Because this study involved the observational analysis of routinely collected clinical data without the collection or testing of human biological specimens, it was conducted in accordance with the Ethical Guidelines for Medical and Health Research Involving Human Subjects in Japan. In accordance with these guidelines, the requirement for written informed consent was waived.

Conflicts of Interest

The authors declare no conflicts of interest.

Tsuji H., Shiga T., Chiba T., et al., “Association of Level 3 Personal Protective Equipment With Intubation Success in the Emergency Department,” Acute Medicine & Surgery 13, no. 1 (2026): e70121, 10.1002/ams2.70121.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.