124 Original article
The effect of personal protective equipment on emergency airway management by emergency physicians: a mannequin study Chung-Cheng Wang, Chung-Hsien Chaou, Chiung-Yao Tseng and Chih-Chuan Lin Objective Emergency medical personnel are at risk of secondary contamination when treating victims of chemical–biological–radiological–nuclear incidents. Hence, it is crucial to train them on the appropriate management of patients involved in chemical–biological–radiological– nuclear incidents. Personal protective equipment (PPE) plays an important role in treating patients suffering from various types of poisoning. However, very few studies have examined whether the use of PPE impedes airway management in an emergency department setting. The present study evaluated the effect of PPE on physicians’ performance of emergency airway management using mannequins. Methods Forty emergency physicians with 1–4 years of experience participated, and were divided by years of experience (1–2 vs. 3–4 years). Each participant both intubated a tracheal tube and inserted a laryngeal mask airway into a mannequin, with and without wearing protection using preassembled intubation aids. The intubation time for both methods was assessed along with participants’ preferences and experiences in airway management.
Results The mean (SD) times to successful tracheal tube/ mask placement with and without protection were similar [tracheal tube: 17.86 s (6.38) vs. 17.83 s (11.13), P = 0.99; laryngeal mask: 10.51 s (4.39) vs. 9.65 s (3.29), P = 0.32]. Conclusion Protective equipment had no effect on physicians’ emergency airway placement time. The effect of wearing PPE is limited if postintubation care is excluded from the evaluation. Furthermore, intubation experience influenced participants’ preferred approach for airway management. European Journal of Emergency Medicine 23:124–129 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. European Journal of Emergency Medicine 2016, 23:124–129 Keywords: airway management, emergency care, personal protective equipment Department of Emergency Medicine, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Tao-Yuan, Taiwan, ROC Correspondence to Chih-Chuan Lin, MD, Department of Emergency Medicine, Lin-Kou Medical Center, Chang Gung Memorial Hospital, No. 5, Fusing Street, Gueishan Township, Taoyuan County 333, Taiwan, ROC Tel: + 886 3 3281200 x 2505; fax: + 886 3 3287715; e-mail: [email protected] Received 3 January 2014 Accepted 31 March 2014
Introduction Emergency medical personnel are at risk of secondary contamination when treating victims of chemical– biological–radiological–nuclear (CBRN) incidents. Without proper protection, healthcare providers may be injured because of secondary exposure, as illustrated in the 1995 Tokyo sarin gas attack [1–3]. Besides protecting medical personnel from secondary exposure to CBRN contaminants, personal protective equipment (PPE) plays an important role in the treatment of patients suffering from various types of poisoning. The authors of one study reported that 22 staff members not wearing PPE suffered secondary exposure to toxic arsenic fumes while treating patients [4]. Contamination from the more common organophosphate poisoning has also been reported [5,6]. The US Environmental Protection Agency classifies PPE as ranging from levels A to D, of which level C is Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (www.euro-emergencymed.com). 0969-9546 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
commonly used for decontamination at medical facilities [7,8]. Level C PPE includes chemical-resistant and biological-resistant clothing for skin protection and airpurifying respirators for airway protection. It has been suggested that patients with toxic chemical contamination should be decontaminated in the field to avoid secondary exposure and transmission of the agent [9] to the medical personnel treating them. However, in countries such as Taiwan, the emergency management system uses a ‘scoop and run’ approach – namely, patients are transported to the hospital or facility within 10 min of the arrival of the emergency service provider; hence, thorough decontamination of patients at the scene is not possible. Moreover, in case of mass casualty incidents, many patients will be admitted to the emergency department in a wild evacuation operation, thereby bypassing the official Emergency Medical Services onsite decontamination protocol [10]. Thus, it is crucial that emergency medicine personnel are trained on how to appropriately manage patients involved in CBRN incidents. DOI: 10.1097/MEJ.0000000000000157
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Effect of PPE on airway management Wang et al. 125
A number of previous studies have investigated the effects of using different levels and types of chemical hazard PPE on airway management in different settings [11–15]. However, few studies have examined as to whether the use of PPE impedes airway management in an emergency department setting. Rapid sequence intubation advocates a mnemonic known as the ‘seven Ps’ to guide emergency medicine physicians: ‘preparation’ (including assembling equipment to provide an alternate airway), ‘preoxygenation’, ‘pretreatment’, ‘paralysis with induction’, ‘protection’, ‘positioning’, ‘placement with proof’ [including visualization of vocal cords, placement of the tracheal tube (TT), cuff inflation, and confirmation of position], and ‘postintubation management’ (securing the TT etc., Appendix 1, Supplemental digital content 1, http://links.lww.com /EJEM/A73) [16]. PPE may prolong the time required for successful airway management because of the loss of dexterity associated with wearing butyl gloves, which are known to affect fine motor coordination [17–19]. In theory, impairment in fine motor coordination may inhibit the preparation and postintubation management [11,13,16] stages of intubation. Furthermore, the use of a respirator with an active filter may inhibit placement with proof. However, findings from a previous study showed that wearing respiratory protection equipment did not affect the resuscitation time [20]. Thus, the question remains as to whether protective gear has an effect on the physicians’ performance during emergencies. Intubation experience may be relevant to physicians’ performance. Familiarity with individual intubation aids may be an important factor when choosing one of these aids [21]. In the present study, the participants were divided into junior and senior groups according to years of experience to determine whether the experience affects the performance and the preferred approach. With reference to the seven Ps of rapid sequence intubation, the purpose of the present study was to evaluate the effect of CBRN-PPE on physicians’ performance of emergency airway management in a simulated emergency medicine setting. This seems to be the first study that systematically tests the impact of CBRN-PPE on intubation by junior and senior emergency physicians using a training mannequin.
Methods Ethical considerations
This study was approved by the Institutional Review Board of our hospital. Study protocol
A prospective, randomized, crossover design was used. Inclusion criteria were the voluntary emergency resident with availability to join the study. Exclusion criteria were heat intolerance and pregnant women. A prestudy power analysis with 10 s between the PPE and the non-PPE
groups was considered to be clinically significant, and using an α error of 0.05 with a power of 0.80 showed that a minimum of 16 participants were required for each study group. Forty emergency physicians of our hospital with 1–4 years of residency experience participated in this study. Participants were divided into a junior group (1–4 years of experience; n = 20) and a senior group (3–4 years of experience; n = 20). All participants signed informed consent and were assigned a study number to ensure anonymity and randomization. The junior and the senior groups performed the intubation and laryngeal mask airway (LMA) according to a randomized list. In each group, half of the participants performed the intubation and LMA without PPE first and then with PPE later. The second half performed the intubation and LMA with PPE first and then without PPE later. Participants’ experience with laryngoscopic intubation was also recorded by noting how many intubation procedures they had completed before the study began. All participants had previously been instructed on the use of each intubation device. Each participant was asked to intubate a mannequin that lay supine on a trolley and insert an LMA with and without level C PPE. The study was conducted in the decontamination area of the emergency room. Each step of the seven Ps was evaluated for PPE-related factors that could potentially prolong the intubation time before the study. Butyl rubber gloves decrease hand dexterity, which may impair effective ‘preparation’ (assembling equipment and preparing an alternate airway), ‘pretreatment,’ ‘paralysis with induction’ (establishing intravenous line), and ‘postintubation management’ (securing the TT), and thus increase the time it takes to intubate. To diminish this negative effect of butyl rubber gloves, an assistant was assigned to each participant to help with the intubation. The assistant wore level C PPE when the airway manager had PPE. All the intubation aids were assembled before intubation (preassembled intubation aids) and included a laryngoscope with an assembled blade and a verified light source, a lubricated TT with a verified inserted stylet and cuff, and a lubricated LMA with a verified cuff. This was considered as a practical way to prepare the intubation aids before wearing PPE. The assistant also temporarily secured the TT after intubation by holding it; permanent fixation was not required (Fig. 1). More appropriate fixation could be performed at a later point. The insertion time was measured from the moment the physician first grasped the laryngoscope or LMA until successful ventilation was achieved (i.e. the TT was placed in the trachea, the cuff inflated, and ventilation initiated through the TT or LMA). Successful insertion and intubation was defined as satisfactory placement of the device on the basis of adequate symmetric expansion of the mannequin’s lung (Laerdal Airway Management Trainer
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126 European Journal of Emergency Medicine 2016, Vol 23 No 2
Montreal, Quebec, Canada), and safety gumboots (Wayne Plastics, Wayne Inyati/WY-1286; Karnataka, India). Finally, a size 4 LMA (The Laryngeal Mask Company Limited; Le Rocher, Victoria, Mahé, Seychelles) and a 7.5 mm cuffed TT were used.
Fig. 1
Statistical analyses
All statistical analyses were performed using SAS statistical software version 8.1 (SAS Institute, Cary, North Carolina, USA). Continuous variables are expressed as the mean (SD), whereas categorical variables are expressed as the frequency (%). Continuous variables were compared between groups by Student’s t-test, whereas categorical variables were compared between groups by the χ2-test. A P value of less than 0.05 was considered to be statistically significant.
Results
Participants used their hands to temporarily secure the tracheal tube after intubation.
Laerdal 250 000; Laerdal, Stavanger, Norway) with the application of an airbag (Laerdal Ambu Bag; Laerdal). Unsuccessful insertion was defined as misplacement of the TT or LMA – a lack of symmetric lung expansion with manual ventilation. No formal system such as end-tidal carbon dioxide detector or stethoscope was used to confirm intubation. This is a limitation of our study using the mannequin model. Participants secured the TT or LMA by hand after placement. Results from previous studies [11,13] suggest that fixing or securing the tube is one of the steps of intubation that would be limited by wearing level C PPE; hence, the fixation time was not assessed in this study. Another reason for not assessing this variable was that tube fixation is routinely performed by nurses, as opposed to physicians, in daily practice. A questionnaire was administrated after testing to evaluate participants’ attitudes towards performing TT/LMA, the subjective influence of PPE on the performance, and their preference of airway management device (TT vs. LMA).
Participants’ laryngoscopic intubation experiences are summarized by groups in Table 1. Half (n = 10) of the participants in the junior group had completed laryngoscopic intubation fewer than 10 times, whereas six participants in this group had completed more than 20 intubations. In the senior group, 80% of participants had completed more than 40 intubations. There was a significant difference in the number of intubations completed between the groups (P < 0.001, Fisher’s exact test). There was no difference between the groups in LMA insertion experience. All participants in the junior group and most participants (n = 19) in the senior group had completed fewer than 10 LMA insertions. Only one had completed LMA insertion more than 10 times. There were no significant differences between the junior and the senior groups in terms of the TT intubation time or the LMA insertion time, with or without level C PPE (Table 2). The overall mean (SD) TT intubation times without and with PPE were 17.83 s (11.13) and 17.86 s (6.38), respectively (P = 0.99). Similarly, the mean LMA insertion times without and with PPE were 9.65 s (3.29) and 10.51 s (4.39), respectively (P = 0.32). Furthermore, there was a statistically significant difference between the TT intubation [M = 17.86 s (6.38)] and LMA insertion times [M = 10.51 s (4.39)] with PPE (P < 0.001) – that is, LMA insertion was much faster than TT intubation. Table 1
Junior groupa (n = 20)
Hazmat PPE and airway control devices
Level C Hazmat PPE is a complete set of equipment that is currently used by medical staff worldwide. The set includes gloves (Ansell Healthcare, Ansell Edmont Sol-Vex 37-175; Juárez, Chihuahua, Mexico), chemical protective clothing (Dupont, Tyvek Barrier Man ‘C’; Shanghai, China), a respirator mask (Bacou-Dalloz, Survivair Premier Plus 322500; Montreal, Quebec, Canada) with active filter (Bacou-Dalloz, Survivair Multi-Contaminant Filter Cartridge;
Laryngoscopic intubation experience by groups
Number of intubations completedb < 10 10 10–20 4 20–30 5 30–40 1 40–50 – > 50 –
Senior group (n = 20)
Total (N = 40)
– – 4 1 2 13
10 4 9 2 2 13
Junior group = 1–2 years of intubation experience; senior group = 3–4 years of intubation experience. Significant difference between the junior and the senior groups (P < 0.001).
a
b
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Effect of PPE on airway management Wang et al. 127
Table 2
Comparison of participants’ airway management times with and without personal protective equipment and by experience group
Junior group (n = 20) Senior group (n = 20) Total (N = 40) Range
TT PPE(− ) (s)
TT PPE(+ ) (s)
LMA PPE(− ) (s)
LMA PPE(+ ) (s)
20.26 (14.62)a 15.41 (5.32) 17.83 (11.13) 8.25–76.05
19.61 (7.60) 16.11 (4.40) 17.86 (6.38) 9.48–41.66
9.97 (3.78) 9.32 (2.79) 9.65 (3.29) 4.60–230.32
10.96 (5.26) 10.06 (3.38) 10.51 (4.39)b 5.27–24.23
LMA, laryngeal mask airway; PPE(− ), without PPE; PPE(+ ), with PPE; TT, tracheal tube. Numbers in parentheses indicate SD. Statistically significant difference when compared with TT PPE(+ ), P < 0.001. No other significant differences were detected.
a
b
Table 3
Participants’ questionnaire responses by experience group Junior group (n = 20)
Questionnaire PPE affects TT insertion Poor vision Loss of hand dexterity Limited body movement PPE affects LMA insertion Poor vision Loss of hand dexterity Limited body movement Prefer TT Prefer LMA
13 8 9 1 7 3 5 1 6 14
(65)a (40) (45) (5) (35) (15) (25) (5) (30) (70)
Senior group (n = 20) 10 7 5 4 6 3 4 1 16 4
(50) (35) (25) (20) (30) (15) (20) (5) (80) (20)
Total (N = 40) 23 15 14 5 13 6 9 2 22 18
(57.5) (37.5) (35) (13) (32.5) (15) (22.5) (5) (55) (45)
LMA, laryngeal mask airway; PPE, personal protective equipment; TT, tracheal tube. a Proportion (% of total).
There were four intubation failures in the junior group (one TT without PPE, two TT with PPE, and one LMA with PPE). There were no intubation failures in the senior group.
the intubation method – that is, experience with intubation – had little effect on the intubation time with PPE, but did influence participants’ preferred approach for airway management.
Participants’ questionnaire feedback is summarized in Table 3. A total of 23 (57.5%) participants thought that level C PPE affected their TT insertion, whereas only 13 (32.5%) participants thought that level C PPE affected their LMA insertion. Interestingly, 22 (55%) participants preferred TT over LMA for airway management when wearing PPE. This was especially true for the senior group, in which 80% preferred this management option. Only a relatively small number of participants felt that vision was impaired while wearing the respirator (15 for TT; six for LMA). Similarly, few participants believed that wearing PPE caused a loss of hand dexterity (14 for TT; nine for LMA). Only one participant believed that the respirator narrowed the operative field. Five participants experienced fog while wearing the respirator.
Findings from most studies suggest that wearing PPE will prolong the intubation time, regardless of the intubation aid used [12,13,15,21]. These findings are mostly attributed to the use of butyl rubber gloves, but not the wearing of full PPE suits or antichemical respirators [20]. Castle et al. [21] proposed that preassembling all intubation aids before attempting intubation may increase the speed of intubation. The findings support this proposition. Preassembling all intubation aids not only increased the speed of intubation, but it may also have other advantages. For example, butyl rubber gloves can also impede establishing intravenous lines, but in a true emergency situation, such as that involving resuscitation of an out-of-hospital cardiac arrest patient, any number of life-saving drugs such as norepinephrine, atropine, lidocaine, and vasopressin can be administrated through the TT immediately, without needing to establish intravenous lines. The EZ-IO intraosseous infusion system for more rapid vascular access [19] and prefilled medication syringes [22] would appear to be of considerable benefit for treating patients with airway complications.
Discussion This seems to be the first study to investigate the influence of PPE on emergency airway management by emergency physicians. Using preassembled intubation aids and having an assistant fix the intubation tube in place appeared to ameliorate the negative effect of wearing butyl gloves, as indicated by the finding that there was no difference in the intubation time with and without PPE. Furthermore, 57.7% participants stated that wearing PPE had an influence on TT intubation, but only 35% participants believed that the influence was caused by a loss of hand dexterity. Finally, familiarity of
Most studies to date have demonstrated that the LMA insertion time is shorter than the TT intubation time overall [11–13,15,21]. Indeed, this is reflected by our findings. Thus, choosing LMA over TT may be better for patients, simply because LMA intubation is faster. Furthermore, Flaishon et al. [12] suggested that LMA intubation should be performed by nonanesthetist
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128 European Journal of Emergency Medicine 2016, Vol 23 No 2
caregivers in cases of nonconventional mass casualty events because LMA does not prolong the intubation time when performed wearing PPE. However, the choice of airway management approach (LMA or TT) should not be based solely on whether the provider is an anesthetist or not. For example, patients (such as those of the sarin terrorist attack) may experience significant respiratory secretion that requires suction, a process that is less convenient with LMA [23]. For chlorine intoxication, the patient may develop laryngeal obstruction and copious oral/pharyngeal/pulmonary secretions, rendering LMA completely unsuitable [24]. Ammonia, a highly watersoluble agent, also induces laryngospasm [25]. Under these circumstances, LMA would not be suitable as the means of airway management. Furthermore, insertion of preassembled TTs or LMAs can be achieved in a very short time. Thus, the underlying cause of the requirement for airway assistance should be considered when determining whether to use TT or LMA. No statistical difference was found in the intubation time between the junior and the senior groups, despite their different levels of experience with intubation. However, the junior group had a higher failure rate than the senior group. In a study that examined the importance of TT insertion training, trainees who had performed only 20 TT insertions had an intubation success rate of more than 90% [26], meaning that they become familiar with it rather quickly. Nevertheless, the findings suggest that familiarity with different intubation aids does not seem to affect the interference caused by wearing the PPE. Notably, the participants in the senior group preferred TT over LMA, whereas the reverse was true for participants in the junior group. Clearly, participants in the senior group had more confidence than those in the junior group in performing TT, which is preferred when a more definite airway must be established than that established by LMA. In contrast, participants in the junior group believed that LMA was preferable because it allowed for more rapid implementation of support than TT. Thus, experience with intubation had little influence on the intubation time with PPE, but did influence participants’ preferred approach for airway management.
Conclusion
Although wearing butyl rubber gloves is associated with a loss of hand dexterity, preassembling intubation aids can help negate this deficit, such that wearing PPE has a minimal impact on emergency airway management. The effect of wearing PPE is limited if postintubation care is excluded from the evaluation. Furthermore, with proper training, either LMA or TT can be a good choice for airway management when wearing PPE, regardless of the physician’s familiarity with different intubation aids. A well-prepared CBRN set, including preassembled intubation aids, would appear to be of considerable benefit for treating patients with CBRN-related respiratory distress. However, data from real-world clinical practice settings are lacking. Comprehensive management guidelines for handling patients involved in CBRN incidents are needed, as is real-world validation in an emergency medicine setting.
Acknowledgements This study was supported partly by the Taiwan Department of Health, grant no. PMRPG390043. Conflicts of interest
There are no conflicts of interest.
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Limitations
The present study had some limitations. First, a longer PPE wearing time can cause delay in real-life situations and stress discomfort in disaster/mass casualty situations. This factor was not considered in the present study. Second, in real-life situations, the patient’s breath can cause haziness on the full face mask, thus interfering with the visibility of the emergency physician. Third, the present study data were collected using a mannequin model, which may not necessarily reflect real-world conditions. Fourth, the effect of wearing a PPE on all seven Ps of rapid sequence intubation was not tested.
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The effect of personal protective equipment on emergency airway management by emergency physicians: a mannequin study Chung-Cheng Wang, Chung-Hsien Chaou, Chiung-Yao Tseng and Chih-Chuan Lin Objective Emergency medical personnel are at risk of secondary contamination when treating victims of chemical–biological–radiological–nuclear incidents. Hence, it is crucial to train them on the appropriate management of patients involved in chemical–biological–radiological– nuclear incidents. Personal protective equipment (PPE) plays an important role in treating patients suffering from various types of poisoning. However, very few studies have examined whether the use of PPE impedes airway management in an emergency department setting. The present study evaluated the effect of PPE on physicians’ performance of emergency airway management using mannequins. Methods Forty emergency physicians with 1–4 years of experience participated, and were divided by years of experience (1–2 vs. 3–4 years). Each participant both intubated a tracheal tube and inserted a laryngeal mask airway into a mannequin, with and without wearing protection using preassembled intubation aids. The intubation time for both methods was assessed along with participants’ preferences and experiences in airway management.
Results The mean (SD) times to successful tracheal tube/ mask placement with and without protection were similar [tracheal tube: 17.86 s (6.38) vs. 17.83 s (11.13), P = 0.99; laryngeal mask: 10.51 s (4.39) vs. 9.65 s (3.29), P = 0.32]. Conclusion Protective equipment had no effect on physicians’ emergency airway placement time. The effect of wearing PPE is limited if postintubation care is excluded from the evaluation. Furthermore, intubation experience influenced participants’ preferred approach for airway management. European Journal of Emergency Medicine 23:124–129 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. European Journal of Emergency Medicine 2016, 23:124–129 Keywords: airway management, emergency care, personal protective equipment Department of Emergency Medicine, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Tao-Yuan, Taiwan, ROC Correspondence to Chih-Chuan Lin, MD, Department of Emergency Medicine, Lin-Kou Medical Center, Chang Gung Memorial Hospital, No. 5, Fusing Street, Gueishan Township, Taoyuan County 333, Taiwan, ROC Tel: + 886 3 3281200 x 2505; fax: + 886 3 3287715; e-mail: [email protected] Received 3 January 2014 Accepted 31 March 2014
Introduction Emergency medical personnel are at risk of secondary contamination when treating victims of chemical– biological–radiological–nuclear (CBRN) incidents. Without proper protection, healthcare providers may be injured because of secondary exposure, as illustrated in the 1995 Tokyo sarin gas attack [1–3]. Besides protecting medical personnel from secondary exposure to CBRN contaminants, personal protective equipment (PPE) plays an important role in the treatment of patients suffering from various types of poisoning. The authors of one study reported that 22 staff members not wearing PPE suffered secondary exposure to toxic arsenic fumes while treating patients [4]. Contamination from the more common organophosphate poisoning has also been reported [5,6]. The US Environmental Protection Agency classifies PPE as ranging from levels A to D, of which level C is Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (www.euro-emergencymed.com). 0969-9546 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
commonly used for decontamination at medical facilities [7,8]. Level C PPE includes chemical-resistant and biological-resistant clothing for skin protection and airpurifying respirators for airway protection. It has been suggested that patients with toxic chemical contamination should be decontaminated in the field to avoid secondary exposure and transmission of the agent [9] to the medical personnel treating them. However, in countries such as Taiwan, the emergency management system uses a ‘scoop and run’ approach – namely, patients are transported to the hospital or facility within 10 min of the arrival of the emergency service provider; hence, thorough decontamination of patients at the scene is not possible. Moreover, in case of mass casualty incidents, many patients will be admitted to the emergency department in a wild evacuation operation, thereby bypassing the official Emergency Medical Services onsite decontamination protocol [10]. Thus, it is crucial that emergency medicine personnel are trained on how to appropriately manage patients involved in CBRN incidents. DOI: 10.1097/MEJ.0000000000000157
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Effect of PPE on airway management Wang et al. 125
A number of previous studies have investigated the effects of using different levels and types of chemical hazard PPE on airway management in different settings [11–15]. However, few studies have examined as to whether the use of PPE impedes airway management in an emergency department setting. Rapid sequence intubation advocates a mnemonic known as the ‘seven Ps’ to guide emergency medicine physicians: ‘preparation’ (including assembling equipment to provide an alternate airway), ‘preoxygenation’, ‘pretreatment’, ‘paralysis with induction’, ‘protection’, ‘positioning’, ‘placement with proof’ [including visualization of vocal cords, placement of the tracheal tube (TT), cuff inflation, and confirmation of position], and ‘postintubation management’ (securing the TT etc., Appendix 1, Supplemental digital content 1, http://links.lww.com /EJEM/A73) [16]. PPE may prolong the time required for successful airway management because of the loss of dexterity associated with wearing butyl gloves, which are known to affect fine motor coordination [17–19]. In theory, impairment in fine motor coordination may inhibit the preparation and postintubation management [11,13,16] stages of intubation. Furthermore, the use of a respirator with an active filter may inhibit placement with proof. However, findings from a previous study showed that wearing respiratory protection equipment did not affect the resuscitation time [20]. Thus, the question remains as to whether protective gear has an effect on the physicians’ performance during emergencies. Intubation experience may be relevant to physicians’ performance. Familiarity with individual intubation aids may be an important factor when choosing one of these aids [21]. In the present study, the participants were divided into junior and senior groups according to years of experience to determine whether the experience affects the performance and the preferred approach. With reference to the seven Ps of rapid sequence intubation, the purpose of the present study was to evaluate the effect of CBRN-PPE on physicians’ performance of emergency airway management in a simulated emergency medicine setting. This seems to be the first study that systematically tests the impact of CBRN-PPE on intubation by junior and senior emergency physicians using a training mannequin.
Methods Ethical considerations
This study was approved by the Institutional Review Board of our hospital. Study protocol
A prospective, randomized, crossover design was used. Inclusion criteria were the voluntary emergency resident with availability to join the study. Exclusion criteria were heat intolerance and pregnant women. A prestudy power analysis with 10 s between the PPE and the non-PPE
groups was considered to be clinically significant, and using an α error of 0.05 with a power of 0.80 showed that a minimum of 16 participants were required for each study group. Forty emergency physicians of our hospital with 1–4 years of residency experience participated in this study. Participants were divided into a junior group (1–4 years of experience; n = 20) and a senior group (3–4 years of experience; n = 20). All participants signed informed consent and were assigned a study number to ensure anonymity and randomization. The junior and the senior groups performed the intubation and laryngeal mask airway (LMA) according to a randomized list. In each group, half of the participants performed the intubation and LMA without PPE first and then with PPE later. The second half performed the intubation and LMA with PPE first and then without PPE later. Participants’ experience with laryngoscopic intubation was also recorded by noting how many intubation procedures they had completed before the study began. All participants had previously been instructed on the use of each intubation device. Each participant was asked to intubate a mannequin that lay supine on a trolley and insert an LMA with and without level C PPE. The study was conducted in the decontamination area of the emergency room. Each step of the seven Ps was evaluated for PPE-related factors that could potentially prolong the intubation time before the study. Butyl rubber gloves decrease hand dexterity, which may impair effective ‘preparation’ (assembling equipment and preparing an alternate airway), ‘pretreatment,’ ‘paralysis with induction’ (establishing intravenous line), and ‘postintubation management’ (securing the TT), and thus increase the time it takes to intubate. To diminish this negative effect of butyl rubber gloves, an assistant was assigned to each participant to help with the intubation. The assistant wore level C PPE when the airway manager had PPE. All the intubation aids were assembled before intubation (preassembled intubation aids) and included a laryngoscope with an assembled blade and a verified light source, a lubricated TT with a verified inserted stylet and cuff, and a lubricated LMA with a verified cuff. This was considered as a practical way to prepare the intubation aids before wearing PPE. The assistant also temporarily secured the TT after intubation by holding it; permanent fixation was not required (Fig. 1). More appropriate fixation could be performed at a later point. The insertion time was measured from the moment the physician first grasped the laryngoscope or LMA until successful ventilation was achieved (i.e. the TT was placed in the trachea, the cuff inflated, and ventilation initiated through the TT or LMA). Successful insertion and intubation was defined as satisfactory placement of the device on the basis of adequate symmetric expansion of the mannequin’s lung (Laerdal Airway Management Trainer
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126 European Journal of Emergency Medicine 2016, Vol 23 No 2
Montreal, Quebec, Canada), and safety gumboots (Wayne Plastics, Wayne Inyati/WY-1286; Karnataka, India). Finally, a size 4 LMA (The Laryngeal Mask Company Limited; Le Rocher, Victoria, Mahé, Seychelles) and a 7.5 mm cuffed TT were used.
Fig. 1
Statistical analyses
All statistical analyses were performed using SAS statistical software version 8.1 (SAS Institute, Cary, North Carolina, USA). Continuous variables are expressed as the mean (SD), whereas categorical variables are expressed as the frequency (%). Continuous variables were compared between groups by Student’s t-test, whereas categorical variables were compared between groups by the χ2-test. A P value of less than 0.05 was considered to be statistically significant.
Results
Participants used their hands to temporarily secure the tracheal tube after intubation.
Laerdal 250 000; Laerdal, Stavanger, Norway) with the application of an airbag (Laerdal Ambu Bag; Laerdal). Unsuccessful insertion was defined as misplacement of the TT or LMA – a lack of symmetric lung expansion with manual ventilation. No formal system such as end-tidal carbon dioxide detector or stethoscope was used to confirm intubation. This is a limitation of our study using the mannequin model. Participants secured the TT or LMA by hand after placement. Results from previous studies [11,13] suggest that fixing or securing the tube is one of the steps of intubation that would be limited by wearing level C PPE; hence, the fixation time was not assessed in this study. Another reason for not assessing this variable was that tube fixation is routinely performed by nurses, as opposed to physicians, in daily practice. A questionnaire was administrated after testing to evaluate participants’ attitudes towards performing TT/LMA, the subjective influence of PPE on the performance, and their preference of airway management device (TT vs. LMA).
Participants’ laryngoscopic intubation experiences are summarized by groups in Table 1. Half (n = 10) of the participants in the junior group had completed laryngoscopic intubation fewer than 10 times, whereas six participants in this group had completed more than 20 intubations. In the senior group, 80% of participants had completed more than 40 intubations. There was a significant difference in the number of intubations completed between the groups (P < 0.001, Fisher’s exact test). There was no difference between the groups in LMA insertion experience. All participants in the junior group and most participants (n = 19) in the senior group had completed fewer than 10 LMA insertions. Only one had completed LMA insertion more than 10 times. There were no significant differences between the junior and the senior groups in terms of the TT intubation time or the LMA insertion time, with or without level C PPE (Table 2). The overall mean (SD) TT intubation times without and with PPE were 17.83 s (11.13) and 17.86 s (6.38), respectively (P = 0.99). Similarly, the mean LMA insertion times without and with PPE were 9.65 s (3.29) and 10.51 s (4.39), respectively (P = 0.32). Furthermore, there was a statistically significant difference between the TT intubation [M = 17.86 s (6.38)] and LMA insertion times [M = 10.51 s (4.39)] with PPE (P < 0.001) – that is, LMA insertion was much faster than TT intubation. Table 1
Junior groupa (n = 20)
Hazmat PPE and airway control devices
Level C Hazmat PPE is a complete set of equipment that is currently used by medical staff worldwide. The set includes gloves (Ansell Healthcare, Ansell Edmont Sol-Vex 37-175; Juárez, Chihuahua, Mexico), chemical protective clothing (Dupont, Tyvek Barrier Man ‘C’; Shanghai, China), a respirator mask (Bacou-Dalloz, Survivair Premier Plus 322500; Montreal, Quebec, Canada) with active filter (Bacou-Dalloz, Survivair Multi-Contaminant Filter Cartridge;
Laryngoscopic intubation experience by groups
Number of intubations completedb < 10 10 10–20 4 20–30 5 30–40 1 40–50 – > 50 –
Senior group (n = 20)
Total (N = 40)
– – 4 1 2 13
10 4 9 2 2 13
Junior group = 1–2 years of intubation experience; senior group = 3–4 years of intubation experience. Significant difference between the junior and the senior groups (P < 0.001).
a
b
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Effect of PPE on airway management Wang et al. 127
Table 2
Comparison of participants’ airway management times with and without personal protective equipment and by experience group
Junior group (n = 20) Senior group (n = 20) Total (N = 40) Range
TT PPE(− ) (s)
TT PPE(+ ) (s)
LMA PPE(− ) (s)
LMA PPE(+ ) (s)
20.26 (14.62)a 15.41 (5.32) 17.83 (11.13) 8.25–76.05
19.61 (7.60) 16.11 (4.40) 17.86 (6.38) 9.48–41.66
9.97 (3.78) 9.32 (2.79) 9.65 (3.29) 4.60–230.32
10.96 (5.26) 10.06 (3.38) 10.51 (4.39)b 5.27–24.23
LMA, laryngeal mask airway; PPE(− ), without PPE; PPE(+ ), with PPE; TT, tracheal tube. Numbers in parentheses indicate SD. Statistically significant difference when compared with TT PPE(+ ), P < 0.001. No other significant differences were detected.
a
b
Table 3
Participants’ questionnaire responses by experience group Junior group (n = 20)
Questionnaire PPE affects TT insertion Poor vision Loss of hand dexterity Limited body movement PPE affects LMA insertion Poor vision Loss of hand dexterity Limited body movement Prefer TT Prefer LMA
13 8 9 1 7 3 5 1 6 14
(65)a (40) (45) (5) (35) (15) (25) (5) (30) (70)
Senior group (n = 20) 10 7 5 4 6 3 4 1 16 4
(50) (35) (25) (20) (30) (15) (20) (5) (80) (20)
Total (N = 40) 23 15 14 5 13 6 9 2 22 18
(57.5) (37.5) (35) (13) (32.5) (15) (22.5) (5) (55) (45)
LMA, laryngeal mask airway; PPE, personal protective equipment; TT, tracheal tube. a Proportion (% of total).
There were four intubation failures in the junior group (one TT without PPE, two TT with PPE, and one LMA with PPE). There were no intubation failures in the senior group.
the intubation method – that is, experience with intubation – had little effect on the intubation time with PPE, but did influence participants’ preferred approach for airway management.
Participants’ questionnaire feedback is summarized in Table 3. A total of 23 (57.5%) participants thought that level C PPE affected their TT insertion, whereas only 13 (32.5%) participants thought that level C PPE affected their LMA insertion. Interestingly, 22 (55%) participants preferred TT over LMA for airway management when wearing PPE. This was especially true for the senior group, in which 80% preferred this management option. Only a relatively small number of participants felt that vision was impaired while wearing the respirator (15 for TT; six for LMA). Similarly, few participants believed that wearing PPE caused a loss of hand dexterity (14 for TT; nine for LMA). Only one participant believed that the respirator narrowed the operative field. Five participants experienced fog while wearing the respirator.
Findings from most studies suggest that wearing PPE will prolong the intubation time, regardless of the intubation aid used [12,13,15,21]. These findings are mostly attributed to the use of butyl rubber gloves, but not the wearing of full PPE suits or antichemical respirators [20]. Castle et al. [21] proposed that preassembling all intubation aids before attempting intubation may increase the speed of intubation. The findings support this proposition. Preassembling all intubation aids not only increased the speed of intubation, but it may also have other advantages. For example, butyl rubber gloves can also impede establishing intravenous lines, but in a true emergency situation, such as that involving resuscitation of an out-of-hospital cardiac arrest patient, any number of life-saving drugs such as norepinephrine, atropine, lidocaine, and vasopressin can be administrated through the TT immediately, without needing to establish intravenous lines. The EZ-IO intraosseous infusion system for more rapid vascular access [19] and prefilled medication syringes [22] would appear to be of considerable benefit for treating patients with airway complications.
Discussion This seems to be the first study to investigate the influence of PPE on emergency airway management by emergency physicians. Using preassembled intubation aids and having an assistant fix the intubation tube in place appeared to ameliorate the negative effect of wearing butyl gloves, as indicated by the finding that there was no difference in the intubation time with and without PPE. Furthermore, 57.7% participants stated that wearing PPE had an influence on TT intubation, but only 35% participants believed that the influence was caused by a loss of hand dexterity. Finally, familiarity of
Most studies to date have demonstrated that the LMA insertion time is shorter than the TT intubation time overall [11–13,15,21]. Indeed, this is reflected by our findings. Thus, choosing LMA over TT may be better for patients, simply because LMA intubation is faster. Furthermore, Flaishon et al. [12] suggested that LMA intubation should be performed by nonanesthetist
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128 European Journal of Emergency Medicine 2016, Vol 23 No 2
caregivers in cases of nonconventional mass casualty events because LMA does not prolong the intubation time when performed wearing PPE. However, the choice of airway management approach (LMA or TT) should not be based solely on whether the provider is an anesthetist or not. For example, patients (such as those of the sarin terrorist attack) may experience significant respiratory secretion that requires suction, a process that is less convenient with LMA [23]. For chlorine intoxication, the patient may develop laryngeal obstruction and copious oral/pharyngeal/pulmonary secretions, rendering LMA completely unsuitable [24]. Ammonia, a highly watersoluble agent, also induces laryngospasm [25]. Under these circumstances, LMA would not be suitable as the means of airway management. Furthermore, insertion of preassembled TTs or LMAs can be achieved in a very short time. Thus, the underlying cause of the requirement for airway assistance should be considered when determining whether to use TT or LMA. No statistical difference was found in the intubation time between the junior and the senior groups, despite their different levels of experience with intubation. However, the junior group had a higher failure rate than the senior group. In a study that examined the importance of TT insertion training, trainees who had performed only 20 TT insertions had an intubation success rate of more than 90% [26], meaning that they become familiar with it rather quickly. Nevertheless, the findings suggest that familiarity with different intubation aids does not seem to affect the interference caused by wearing the PPE. Notably, the participants in the senior group preferred TT over LMA, whereas the reverse was true for participants in the junior group. Clearly, participants in the senior group had more confidence than those in the junior group in performing TT, which is preferred when a more definite airway must be established than that established by LMA. In contrast, participants in the junior group believed that LMA was preferable because it allowed for more rapid implementation of support than TT. Thus, experience with intubation had little influence on the intubation time with PPE, but did influence participants’ preferred approach for airway management.
Conclusion
Although wearing butyl rubber gloves is associated with a loss of hand dexterity, preassembling intubation aids can help negate this deficit, such that wearing PPE has a minimal impact on emergency airway management. The effect of wearing PPE is limited if postintubation care is excluded from the evaluation. Furthermore, with proper training, either LMA or TT can be a good choice for airway management when wearing PPE, regardless of the physician’s familiarity with different intubation aids. A well-prepared CBRN set, including preassembled intubation aids, would appear to be of considerable benefit for treating patients with CBRN-related respiratory distress. However, data from real-world clinical practice settings are lacking. Comprehensive management guidelines for handling patients involved in CBRN incidents are needed, as is real-world validation in an emergency medicine setting.
Acknowledgements This study was supported partly by the Taiwan Department of Health, grant no. PMRPG390043. Conflicts of interest
There are no conflicts of interest.
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Limitations
The present study had some limitations. First, a longer PPE wearing time can cause delay in real-life situations and stress discomfort in disaster/mass casualty situations. This factor was not considered in the present study. Second, in real-life situations, the patient’s breath can cause haziness on the full face mask, thus interfering with the visibility of the emergency physician. Third, the present study data were collected using a mannequin model, which may not necessarily reflect real-world conditions. Fourth, the effect of wearing a PPE on all seven Ps of rapid sequence intubation was not tested.
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