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Adoption of low tidal volume ventilation in the emergency department: A quality improvement intervention
YAJEM-58304; No of Pages 5 American Journal of Emergency Medicine xxx (xxxx) xxx
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Adoption of low tidal volume ventilation in the emergency department: A quality improvement intervention☆,☆☆ Matthew E. Prekker, MD, MPH a,b,⁎, Crystal Donelan, MD a,1, Sum Ambur, MD a, Brian E. Driver, MD a, Alex O'Brien-Lambert, MD a,2, Daniel G. Hottinger, MD a,3, Alexander B. Adams, MPH, RRT b,c a b c
Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, MN, United States of America Department of Medicine, Division of Pulmonary and Critical Care, Hennepin County Medical Center, Minneapolis, MN, United States of America Respiratory Therapy Department, Hennepin County Medical Center, Minneapolis, MN, United States of America
a r t i c l e
i n f o
Article history: Received 8 May 2019 Received in revised form 7 June 2019 Accepted 14 June 2019 Available online xxxx Keywords: Emergency department Tidal volume Mechanical ventilation Quality improvement
a b s t r a c t Background: Ventilator tidal volumes of N8 mL/kg of predicted body weight (PBW) may increase the risk of lung injury. We sought to evaluate the impact of a quality improvement intervention among intubated Emergency Department (ED) patients to protocolize the prescription of low tidal volume ventilation. Methods: In this before-and-after study, the average tidal volume delivered to ED patients receiving volume assist-control ventilation was compared before (2007–2014) and after (2015–2016) implementation of a ventilator initiation protocol (the quality improvement intervention). The intervention emphasized 1) measurement of the patient's height to calculate PBW and therefore tailor the tidal volume to estimated lung size (b8 mL/kg PBW), and 2) focused education and reference materials for ED physicians and respiratory therapists. Results: Among ventilated ED patients meeting inclusion criteria in the before (N = 2185) and after (N = 774) cohorts, the mean (±SD) tidal volume decreased from 9.0 ± 1.4 mL/kg to 7.2 ± 0.9 mL/kg PBW following the intervention (absolute difference 1.8 mL/kg, 95% confidence interval 1.7 to 1.9 mL/kg, p b 0.001). The proportion of patients receiving low tidal volume ventilation increased after the intervention (72%), as compared to before (23%). Low tidal volume ventilation continued to be utilized at 24 h after ICU admission in patients who remained intubated in the cohort following the intervention (mean tidal volume 7.3 mL/kg PBW). Conclusions: Pairing a ventilator initiation protocol with focused education and resources for emergency physicians and respiratory therapists was associated with a significant reduction in tidal volume delivered to ED patients. © 2019 Elsevier Inc. All rights reserved.
1. Introduction
Abbreviations: ARDS, acute respiratory distress syndrome; PBW, predicted body weight; PEEP, positive end expiratory pressure. ☆ Presented at the Society for Academic Emergency Medicine Annual Meeting on May 18, 2017 in Orlando, FL. ☆☆ This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. ⁎ Corresponding author at: Hennepin County Medical Center, 701 Park Ave South, Mailcode G5, Minneapolis, MN 55415, United States of America. E-mail addresses: [email protected] (M.E. Prekker), [email protected] (C. Donelan), [email protected] (S. Ambur), [email protected] (B.E. Driver), [email protected] (A. O'Brien-Lambert), [email protected] (D.G. Hottinger). 1 Present address/affiliation: Department of Emergency Medicine, George Washington University, Washington, DC, United States of America. 2 Present address/affiliation: Department of Emergency Medicine, University of Washington School of Medicine, Seattle, WA, United States of America. 3 Present address/affiliation: Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA, United States of America.
Mechanical ventilation is commonly used in the Emergency Department (ED) to support oxygenation and ventilation in patients with pulmonary dysfunction or an ineffective respiratory drive. The ventilator generates a tidal volume by applying non-physiologic positive pressure to the airways which can damage fragile lung tissue and contribute to complications such as the acute respiratory distress syndrome (ARDS) [1]. The risk for ventilator-induced lung injury begins as soon as a patient is intubated and is higher when excessive pressure (barotrauma) or tidal volume (volutrauma) is delivered [2]. This is the rationale for the consensus recommendation that all patients who require mechanical ventilation, regardless of the presence of lung injury, receive lung protective settings [3-5]. A key component of lung protective ventilation is low tidal volume ventilation (b8 mL per kilogram predicted body weight [PBW], which is a function of patient sex and height so correlates tightly with actual lung size) with close monitoring of airway pressures (e.g. targeting airway pressure during an inspiratory hold maneuver [plateau pressure] b 30 cm of water) [6].
https://doi.org/10.1016/j.ajem.2019.06.026 0735-6757/© 2019 Elsevier Inc. All rights reserved.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
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M.E. Prekker et al. / American Journal of Emergency Medicine xxx (xxxx) xxx
A fundamental skill in emergency medicine is safe and efficient endotracheal intubation, yet many ED patients subsequently receive mechanical ventilation characterized by excessive tidal volume, high fraction of inspired oxygen, and low positive end-expiratory pressure (PEEP) [7,8]. This discrepancy highlights a sizeable opportunity to improve the quality and safety of ED mechanical ventilation and potentially impact patient outcome. In observational studies, excessive ED tidal volume has been independently associated with an increase in hospital mortality as well as a lower neurologically-favorable survival after out-of-hospital cardiac arrest [9,10]. Moreover, early optimization of ED ventilator settings appears to correlate with greater use of low tidal volume ventilation in the ICU, as ventilator settings are rarely adjusted in the first 24 h [8,11]. Therefore, the goal of this investigation is to evaluate the impact of a quality improvement intervention designed to increase the adoption of ED low tidal volume ventilation among respiratory therapists and ED physicians caring for intubated patients. 2. Methods 2.1. Study design and setting This observational study with a before-and-after design was conducted in an urban, academic, safety net hospital and Level 1 Trauma Center with an annual ED census of approximately 105,000 visits. We evaluated the impact of a quality improvement initiative that engaged emergency physicians and respiratory therapists in the implementation of low tidal volume ventilation for all patients undergoing endotracheal intubation and mechanical ventilation in the ED. The total study period spanned nine years (2007–2016) and was divided into three phases: 1) “Before” phase lasting seven years and capturing baseline ED and early ICU ventilator settings on consecutive patients intubated in the ED, 2) “Intervention” phase lasting 8 months and involving implementation of an institution-wide low tidal volume ventilation protocol and accompanying didactics, and 3) “After” phase lasting 12 months and capturing the same ED and early ICU ventilator settings as in the baseline phase, from newly intubated ED patients. The institutional review board for human subjects approved this study with a waiver of informed consent. 2.2. Study population We performed a structured query of our electronic medical record (Epic, Verona WI) to identify consecutive mechanicallyventilated ED patients meeting inclusion criteria during the before and after-intervention periods. Inclusion criteria were as follows: age N18 years, intubated during the index ED visit, and volumetargeted mechanical ventilation. Patients were excluded from analysis if their height was not recorded in the electronic medical record (precluding calculation of predicted body weight) or if they died in the ED or within 24 h of ICU admission. Emergency physicians and respiratory therapists participated in the study by taking part in the study intervention (training in and implementing a low tidal volume ventilation protocol). 2.3. Study protocol A protocol for the initiation of mechanical ventilation was devised using the best available evidence and was evaluated by local content experts and ultimately approved as hospital policy by the committees on practice standards and patient safety at our institution (Fig. 1). The purpose of this algorithm is to guide the initiation of volume-targeted mechanical ventilation and assure that the selected tidal volume is indexed to predicted body weight (PBW), a surrogate for lung size (i.e. mL/kg PBW). Predicted body weight is calculated from the patient's height and sex as follows: for men, PBW = 50 + (0.91)[height(cm)
− 152.4], and for women, PBW = 45.5 + (0.91)[height(cm) − 152.4]. We defined low tidal volume ventilation as the prescription of an initial tidal volume of b8 mL/kg PBW. This initiative was complimentary to a pre-existing, institution-wide mechanical ventilation bundle which directs head-of-bed elevation, oral hygiene, and criteria for ventilator weaning trials designed to prevent pulmonary complications in intubated patients. The respiratory therapy manager provided structured education on the protocol at select change-of-shift times during the intervention phase. Likewise, a physician board-certified and practicing emergency medicine, pulmonology, and critical care medicine lectured to emergency medicine faculty and residents and championed protocol adoption during this same 8-month period. Both groups of clinicians were provided with just-in-time reference materials which included laminated, badge-sized cards with height versus tidal volume tables (these cards were also affixed to the ED transport ventilators), as well as disposable tape measures. In general, throughout the study, the ED respiratory therapist determines the height of the intubated patient and selects the initial tidal volume in collaboration with the emergency physician and third-year emergency medicine resident. Physicians or respiratory therapists were encouraged to tailor the respiratory rate to the acid/base status of the patient and/or decrease the tidal volume depending on clinical context or airway pressures.
2.4. Key outcome measures We chose as the primary outcome the absolute difference in mean tidal volumes among mechanically-ventilated ED patients during the periods before (2007–2014) and after (2015–2016) implementation of the low tidal volume ventilation protocol. Secondary outcomes were the proportion of ED patients with a lung-protective tidal volume (b8 mL/kg PBW) and duration of mechanical ventilation, ICU length of stay, and hospital mortality. In addition, we were interested in the impact of adherence to ED low tidal volume ventilation and subsequent delivered tidal volumes in the ICU. Specifically, we were interested in the proportion of patients receiving mechanical ventilation for at least 24 h who did not receive lung protective ventilation in the ED but subsequently had their tidal volume reduced to lung protective settings in the ICU. To evaluate these outcomes, we recorded exhaled tidal volume, respiratory rate, fraction of inspired oxygen, and positive end-expiratory pressure (PEEP), as well as static and dynamic airway pressures when available; this data was captured at three distinct time points, 1) following ED intubation (time zero [T0]), 2) at the time of ICU arrival (T1), and 3) after 24 h in the ICU (T2).
2.5. Data analysis To characterize our sample and evaluate adherence to lung protective ventilation, we used descriptive statistics to summarize ventilator settings, patient demographics and anthropometrics, and key outcome variables [duration of mechanical ventilation, length-of-stay, and hospital survival]. We also analyze secular trends in the adoption of lung protective ventilation over time, both before and after the intervention. We summarize the distribution of continuous variables using mean and standard deviation for normally-distributed data or median and interquartile range for non-normally distributed data; categorical data is summarized as proportions. We report absolute differences in group means with accompanying 95% confidence intervals for the primary study outcome and use an unpaired t-test to assess for statistical significance. We performed all data analysis using STATA version 10 (StataCorp, College Station, TX) and considered a two-tailed p value b0.05 as statistically significant.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
M.E. Prekker et al. / American Journal of Emergency Medicine xxx (xxxx) xxx
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Fig. 1. ED protocol for initial ventilator settings. F, frequency of respirations; IBW, ideal body weight; Ti, inspiratory time; FIO2, fraction of inspired oxygen; PEEP, positive end-expiratory pressure; PIP, peak inspiratory pressure; Pplat, end-inspiratory plateau pressure.
3. Results A total of 2959 mechanically-ventilated ED patients were included in the study (Fig. 2). Patient characteristics were similar before and after implementing the low tidal volume ventilation protocol (Table 1). Patient height was documented in the ED medical record more frequently after the intervention as compared to before (97% vs. 65% of cases, respectively, Fig. 2); height is necessary to calculate predicted body weight which is used to prescribe tidal volume according to the study protocol. The mean tidal volume (±standard deviation [SD]) delivered in the ED was 9.0 ± 1.4 mL/kg PBW before the intervention as compared to 7.2 ± 0.9 mL/kg PBW after the intervention (absolute difference 1.8 mL/kg, 95% confidence interval [CI] 1.7 to 1.9 mL/kg, p b 0.001) (Fig. 3). Similarly, the proportion of ED patients ventilated with low tidal volume ventilation (tidal volume of b8 mL/kg PBW) was higher post-intervention as compared to pre-intervention (72% versus 23%, respectively, p b 0.001)
(Table 2). A secular trend in the adoption of low tidal volume ventilation over time was not observed prior to the study intervention (Fig. 4). Considering subsequent ventilation of these patients in the ICU, a difference in mean tidal volume and the proportion of patients receiving low tidal volume ventilation was observed before and after the intervention; these differences were of a similar direction and magnitude to those observed in the ED setting (Fig. 3 and Table 2). After the intervention, a higher proportion of ED patients who initially received high tidal volumes were switched to low tidal volume ventilation in the ICU, as compared to pre-intervention (55% [118/214 patients] vs. 7% [118/1684 patients], p b 0.001). 4. Discussion The routine use of low tidal volume ventilation for the approximately 250,000 ED patients requiring mechanical ventilation may
Fig. 2. Study flow diagram.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
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Table 1 Patient characteristics and outcomes.
Table 2 Tidal volumes before and after the study intervention stratified by time point or ICU.
Characteristic
Pre-intervention period (N = 2185)
Age, mean (SD), y Male sex, N (%) Body mass index, mean (SD), kg/m2 Predicted body weight, mean (SD), kg Ratio of PaO2 to FIO2, mean (SD) ED length of stay, median (IQR), h ED disposition, N (%) Medical ICU Surgical ICU Operating room Hospital outcomes Duration of mechanical ventilation, median (IQR), d ICU length of stay, median (IQR), d Hospital length of stay, median (IQR), d Hospital mortality, N (%)
49 1465 29 68 323 1.8
(17) (67) (8) (11) (158) (1.2–2.8)
1408 (64) 674 (31) 103 (5)
Pre-intervention period (N = 2185)
Post-intervention period (N = 774) 48 535 28 69 313 1.6
(19) (69) (7) (10) (161) (1.1–2.6)
491 (63) 246 (32) 37 (5)
1.4 (0.6–4.6)
1.3 (0.5–5.3)
2.7 (1.2–7.7) 7.2 (3.3–14) 188 (9)
1.6 (0.8–4.6) 4.6 (1.7–11) 107 (14)
represent a low-effort strategy to improve the quality of ED critical care delivery. Indeed, intubated patients sometimes spend hours to days in the ED at institutions where available ICU beds can be scarce [8,12]. Early work in this area appears promising; a large, before-and-after study found that both pulmonary complications and hospital mortality decreased after adoption of a comprehensive “lung protective” ventilator protocol in the ED involving volume-targeted ventilation maintaining a plateau airway pressure b 30 cm of water, prevention of hyperoxia, and head-of-bed elevation to prevent aspiration [9]. In the current study, we observed a significant increase in the prescription of low tidal volume ventilation to intubated ED patients after implementation of a ventilator initiation protocol and focused education, as compared with historical practices in our ED. This intervention targeting emergency physicians and respiratory therapists is both feasible and durable, as the use of low tidal volumes persisted for at least the first day in the ICU, all of which should serve to reduce the likelihood of VILI among mechanically-ventilated ED patients. Several aspects of this quality improvement intervention deserve special attention. First, the ED respiratory therapists' standard work for initiating a patient on invasive mechanical ventilation underwent a foundational change, beginning with the accurate measurement of patient height using disposable tape measures stocked on the ED airway
Fig. 3. Box plots summarizing the distribution of tidal volumes before and after the low tidal volume ventilation intervention. The three time points in each period represent the tidal volume on initial ED settings, at ICU admission, and after 24 h in the ICU. The box represents the interquartile range, the vertical line inside is the median value, and the whiskers show upper and lower adjacent values for each group.
Tidal volume, mean (SD), mL/kg PBW ED initial setting ICU arrival ICU after 24 h Tidal volume, mean (SD), mL ED initial setting ICU arrival ICU after 24 h Tidal volume b8 mL/kg PBW, N (%) ED initial setting ICU after 24 h ICU tidal volume after 24 h, mean (SD), mL/kg PBW Medical ICU Surgical/trauma ICU
Post-intervention period (N = 774)
9.0 (1.4) 8.9 (1.3) 9.1 (1.4)
7.2 (0.9) 7.1 (0.9) 7.3 (0.9)
597 (74) 593 (74) 603 (73)
489 (72) 487 (71) 494 (71)
501 (23) 446 (20)
560 (72) 643 (83)
9.0 (1.4) 9.1 (1.3)
7.2 (0.9) 7.3 (0.9)
cart (height allows calculation of PBW). Before the intervention, over one-third of patients (N = 1371 or 35%) intubated in the ED did not have their height documented in the medical record and were excluded from further analysis. Anecdotally, before the intervention, clinicians frequently chose a round number for tidal volume in milliliters, typically 550 or 600 mL in an adult, which led to missed opportunities to optimize lung protection. Similarly, visual height estimation was another technique employed but it is also associated with systematic overestimation of PBW and inappropriately large tidal volumes [13]. Second, this attempt at quality improvement benefitted greatly from a physician and respiratory therapy champion; these individuals provided leadership, feedback, and tailored education to providers during and after the 8-month intervention period. We would speculate that the professional background of a clinician champion is perhaps less important than their enthusiasm and engagement. There are data to suggest ED nurses have the expertise and motivation to serve in such a capacity as well [14]. The study intervention was associated with a reduction in tidal volume of 1.8 mL/kg PBW, on average, to an absolute value of 7.2 mL/kg PBW which is consistent with current practice at other large, academic hospitals active in critical care research such as Prevention and Early Treatment of Acute Lung Injury (PETAL) network sites or the international LUNG SAFE investigators [15,16]. While an initial tidal volume ≤ 8 mL/kg PBW is desirable according to a meta-analysis [17], the utility of further reduction to 6 mL/kg PBW in ventilated patients without ARDS is controversial [18,19]. The recent PReVENT randomized trial, evaluating the effect of a low (6 mL/kg PBW) versus intermediate (b10 mL/kg) tidal volume strategy on ventilator-free days at day 28 in ICU patients without ARDS receiving mechanical ventilation, was negative for this primary outcome but also lacked any significant difference in adverse events in the two arms [20]. Interestingly, the median baseline tidal volume at randomization in the groups subsequently assigned to the low and intermediate tidal volume strategies was 7.0 and 7.3 mL/kg PBW, respectively, similar to the post-intervention cohort in the current study. We did not collect adverse event data; we suspect the observed increase in hospital mortality between the preintervention (9%) and post-intervention (14%) phases reflected secular trends in case mix and patient acuity rather than an association with the ventilator settings protocol, but this cannot be entirely excluded. Finally, perhaps a more sophisticated parameter than tidal volume indexed to lung size (i.e. PBW), such as driving pressure or mechanical power, would be better able to discriminate protective from injurious mechanical ventilation practices and could be incorporated into future ED protocols [21]. This study has several limitations. The pre-post study design is vulnerable to temporal trends in ED or ICU critical care practices which may have influenced prescribed tidal volume apart from the study
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
M.E. Prekker et al. / American Journal of Emergency Medicine xxx (xxxx) xxx
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Fig. 4. Annual proportion of intubated ED patients receiving low tidal volume ventilation.
quality improvement intervention. However, our analysis for secular changes in tidal volume during the entire study period did not support this (Fig. 4). We did not study pulmonary complications such as the development of ARDS, pneumonia, incident pneumothorax, patientventilator dyssynchrony, or use of sedation/paralysis during the study period which precludes any comment on patient-centered outcomes associated with the observed reduction in delivered tidal volume. Furthermore, airway pressures such as the plateau pressure were not systemically recorded in the ED during the study period to corroborate the speculative benefit of reducing tidal volume in this population. The single-center design and exclusion of the few patients on nonvolume-targeted ventilator modes may limit the generalizability of our findings to other settings or ED ventilator strategies. 4.1. Conclusions This pre-post study demonstrates that implementation of a low tidal volume ventilation protocol to guide initial mechanical ventilation settings, accompanied by focused education for physicians and respiratory therapists, was feasible and associated with a significant reduction in tidal volume among intubated ED patients. Protocol deployment in the ED also appeared to positively influence delivered tidal volume in the ICU. This is important as many hospitals have reported limited penetrance of lung protective ventilation strategies in intubated patients at risk for or meeting the diagnostic criteria for ARDS [22]. The quality improvement process described here may serve as a guide for other institutions who seek to reduce variability in the prescription of mechanical ventilation and protect the lungs from iatrogenic injury. References [1] Slutsky AS, Ranieri VM. Ventilator-induced lung injury. N Engl J Med 2013;369(22): 2126–36. [2] Fuller BM, Mohr NM, Hotchkiss RS, Kollef MH. Reducing the burden of acute respiratory distress syndrome: the case for early intervention and the potential role of the emergency department. Shock 2014;41(5):378–87. [3] Weingart SD. Managing initial mechanical ventilation in the emergency department. Ann Emerg Med 2016;68:614–7. [4] Mosier JM, Hypes C, Joshi R, Whitmore S, Parthasarathy S, Cairns CB. Ventilator strategies and rescue therapies for management of acute respiratory failure in the emergency department. Ann Emerg Med 2015;66:529–41.
[5] Stephens RJ, Siegler JE, Fuller BM. Mechanical ventilation in the prehospital and emergency department environment. Respir Care 2019;64(5):595–603. [6] Kilickaya O, Gajic O. Initial ventilator settings for critically ill patients. Crit Care 2013; 17(2):123–4. [7] Fuller BM, Mohr NM, Miller CN, et al. Mechanical ventilation and ARDS in the ED: a multicenter, observational, prospective, cross-sectional study. Chest 2015;148(2): 365–74. [8] Wilcox SR, Richards JB, Fisher DF, Sankoff J, Seigel TA. Initial mechanical ventilator settings and lung protective ventilation in the ED. Am J Emerg Med 2016;34(8): 1446–51. [9] Fuller BM, Ferguson IT, Mohr NM, et al. Lung-protective ventilation initiated in the emergency department (LOV-ED): a quasi-experimental, before-after trial. Ann Emerg Med 2017;70:406–18. [10] Beitler JR, Ghafouri TB, Jinadasa SP, et al. Favorable neurocognitive outcome with low tidal volume ventilation after cardiac arrest. Am J Respir Crit Care Med 2017; 195(9):1198–206. [11] Sjoding MW, Gong MN, Haas CF, Iwashyna TJ. Evaluating delivery of low tidal volume ventilation in six ICUs using electronic health record data. Crit Care Med 2019;47(1):56–61. [12] Hung SC, Kung CT, Hung CW, et al. Determining delayed admission to intensive care unit for mechanically ventilated patients in the emergency department. Crit Care 2014;18(4):485. [13] Sasko B, Thiem U, Christ M, Trappe HJ, Ritter O, Pagonas N. Size matters: an observational study investigating estimated height as a reference size for calculating tidal volumes if low tidal volume ventilation is required. PLoS One 2018;13(6):e0199917. [14] Cornish S, Wynne R, Klim S, Kelly AM. Protective lung strategies: a cross sectional survey of nurses' knowledge and use in the emergency department. Australas Emerg Nurs J 2017;20(2):87–91. [15] Lanspa MJ, Gong MN, Schoenfeld DA, et al. Prospective assessment of the feasibility of a trial of low-tidal volume ventilation for patients with acute respiratory failure. Ann Am Thorac Soc 2019;16:356–62. [16] Belani G, Laffey JG, Pham T, et al. Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries. JAMA 2016;315:788–800. [17] Neto AS, Simonis FD, Barbas CS, et al. Lung-protective ventilation with low tidal volumes and the occurrence of pulmonary complications in patients without acute respiratory distress syndrome: a systematic review and individual patient data analysis. Crit Care Med 2015;43(10):2155–63. [18] Ferguson ND. Low tidal volumes for all? JAMA 2012;308:1689–90. [19] Bonatti G, Robba C, Ball L, Silva PL, Rocco PRM, Pelosi P. Controversies when using mechanical ventilation in obese patients with and without acute respiratory distress syndrome. Expert Rev Respir Med 2019;13(5):471–9. [20] Simonis FD, Serpa Neto A, Binnekade JM, et al. Effect of a low vs intermediate tidal volume strategy on ventilator-free days in intensive care unit patients without ARDS: a randomized clinical trial. JAMA 2018;320:1872–80. [21] Tonetti T, Vasques F, Rapetti F, et al. Driving pressure and mechanical power: new targets for VILI prevention. Ann Transl Med 2017;5:286. [22] Umoh NJ, Fan E, Mendez-Tellez PA, et al. Patient and intensive care unit organizational factors associated with low tidal volume ventilation in acute lung injury. Crit Care Med 2008;36:1463–8.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Adoption of low tidal volume ventilation in the emergency department: A quality improvement intervention☆,☆☆ Matthew E. Prekker, MD, MPH a,b,⁎, Crystal Donelan, MD a,1, Sum Ambur, MD a, Brian E. Driver, MD a, Alex O'Brien-Lambert, MD a,2, Daniel G. Hottinger, MD a,3, Alexander B. Adams, MPH, RRT b,c a b c
Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, MN, United States of America Department of Medicine, Division of Pulmonary and Critical Care, Hennepin County Medical Center, Minneapolis, MN, United States of America Respiratory Therapy Department, Hennepin County Medical Center, Minneapolis, MN, United States of America
a r t i c l e
i n f o
Article history: Received 8 May 2019 Received in revised form 7 June 2019 Accepted 14 June 2019 Available online xxxx Keywords: Emergency department Tidal volume Mechanical ventilation Quality improvement
a b s t r a c t Background: Ventilator tidal volumes of N8 mL/kg of predicted body weight (PBW) may increase the risk of lung injury. We sought to evaluate the impact of a quality improvement intervention among intubated Emergency Department (ED) patients to protocolize the prescription of low tidal volume ventilation. Methods: In this before-and-after study, the average tidal volume delivered to ED patients receiving volume assist-control ventilation was compared before (2007–2014) and after (2015–2016) implementation of a ventilator initiation protocol (the quality improvement intervention). The intervention emphasized 1) measurement of the patient's height to calculate PBW and therefore tailor the tidal volume to estimated lung size (b8 mL/kg PBW), and 2) focused education and reference materials for ED physicians and respiratory therapists. Results: Among ventilated ED patients meeting inclusion criteria in the before (N = 2185) and after (N = 774) cohorts, the mean (±SD) tidal volume decreased from 9.0 ± 1.4 mL/kg to 7.2 ± 0.9 mL/kg PBW following the intervention (absolute difference 1.8 mL/kg, 95% confidence interval 1.7 to 1.9 mL/kg, p b 0.001). The proportion of patients receiving low tidal volume ventilation increased after the intervention (72%), as compared to before (23%). Low tidal volume ventilation continued to be utilized at 24 h after ICU admission in patients who remained intubated in the cohort following the intervention (mean tidal volume 7.3 mL/kg PBW). Conclusions: Pairing a ventilator initiation protocol with focused education and resources for emergency physicians and respiratory therapists was associated with a significant reduction in tidal volume delivered to ED patients. © 2019 Elsevier Inc. All rights reserved.
1. Introduction
Abbreviations: ARDS, acute respiratory distress syndrome; PBW, predicted body weight; PEEP, positive end expiratory pressure. ☆ Presented at the Society for Academic Emergency Medicine Annual Meeting on May 18, 2017 in Orlando, FL. ☆☆ This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. ⁎ Corresponding author at: Hennepin County Medical Center, 701 Park Ave South, Mailcode G5, Minneapolis, MN 55415, United States of America. E-mail addresses: [email protected] (M.E. Prekker), [email protected] (C. Donelan), [email protected] (S. Ambur), [email protected] (B.E. Driver), [email protected] (A. O'Brien-Lambert), [email protected] (D.G. Hottinger). 1 Present address/affiliation: Department of Emergency Medicine, George Washington University, Washington, DC, United States of America. 2 Present address/affiliation: Department of Emergency Medicine, University of Washington School of Medicine, Seattle, WA, United States of America. 3 Present address/affiliation: Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA, United States of America.
Mechanical ventilation is commonly used in the Emergency Department (ED) to support oxygenation and ventilation in patients with pulmonary dysfunction or an ineffective respiratory drive. The ventilator generates a tidal volume by applying non-physiologic positive pressure to the airways which can damage fragile lung tissue and contribute to complications such as the acute respiratory distress syndrome (ARDS) [1]. The risk for ventilator-induced lung injury begins as soon as a patient is intubated and is higher when excessive pressure (barotrauma) or tidal volume (volutrauma) is delivered [2]. This is the rationale for the consensus recommendation that all patients who require mechanical ventilation, regardless of the presence of lung injury, receive lung protective settings [3-5]. A key component of lung protective ventilation is low tidal volume ventilation (b8 mL per kilogram predicted body weight [PBW], which is a function of patient sex and height so correlates tightly with actual lung size) with close monitoring of airway pressures (e.g. targeting airway pressure during an inspiratory hold maneuver [plateau pressure] b 30 cm of water) [6].
https://doi.org/10.1016/j.ajem.2019.06.026 0735-6757/© 2019 Elsevier Inc. All rights reserved.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
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A fundamental skill in emergency medicine is safe and efficient endotracheal intubation, yet many ED patients subsequently receive mechanical ventilation characterized by excessive tidal volume, high fraction of inspired oxygen, and low positive end-expiratory pressure (PEEP) [7,8]. This discrepancy highlights a sizeable opportunity to improve the quality and safety of ED mechanical ventilation and potentially impact patient outcome. In observational studies, excessive ED tidal volume has been independently associated with an increase in hospital mortality as well as a lower neurologically-favorable survival after out-of-hospital cardiac arrest [9,10]. Moreover, early optimization of ED ventilator settings appears to correlate with greater use of low tidal volume ventilation in the ICU, as ventilator settings are rarely adjusted in the first 24 h [8,11]. Therefore, the goal of this investigation is to evaluate the impact of a quality improvement intervention designed to increase the adoption of ED low tidal volume ventilation among respiratory therapists and ED physicians caring for intubated patients. 2. Methods 2.1. Study design and setting This observational study with a before-and-after design was conducted in an urban, academic, safety net hospital and Level 1 Trauma Center with an annual ED census of approximately 105,000 visits. We evaluated the impact of a quality improvement initiative that engaged emergency physicians and respiratory therapists in the implementation of low tidal volume ventilation for all patients undergoing endotracheal intubation and mechanical ventilation in the ED. The total study period spanned nine years (2007–2016) and was divided into three phases: 1) “Before” phase lasting seven years and capturing baseline ED and early ICU ventilator settings on consecutive patients intubated in the ED, 2) “Intervention” phase lasting 8 months and involving implementation of an institution-wide low tidal volume ventilation protocol and accompanying didactics, and 3) “After” phase lasting 12 months and capturing the same ED and early ICU ventilator settings as in the baseline phase, from newly intubated ED patients. The institutional review board for human subjects approved this study with a waiver of informed consent. 2.2. Study population We performed a structured query of our electronic medical record (Epic, Verona WI) to identify consecutive mechanicallyventilated ED patients meeting inclusion criteria during the before and after-intervention periods. Inclusion criteria were as follows: age N18 years, intubated during the index ED visit, and volumetargeted mechanical ventilation. Patients were excluded from analysis if their height was not recorded in the electronic medical record (precluding calculation of predicted body weight) or if they died in the ED or within 24 h of ICU admission. Emergency physicians and respiratory therapists participated in the study by taking part in the study intervention (training in and implementing a low tidal volume ventilation protocol). 2.3. Study protocol A protocol for the initiation of mechanical ventilation was devised using the best available evidence and was evaluated by local content experts and ultimately approved as hospital policy by the committees on practice standards and patient safety at our institution (Fig. 1). The purpose of this algorithm is to guide the initiation of volume-targeted mechanical ventilation and assure that the selected tidal volume is indexed to predicted body weight (PBW), a surrogate for lung size (i.e. mL/kg PBW). Predicted body weight is calculated from the patient's height and sex as follows: for men, PBW = 50 + (0.91)[height(cm)
− 152.4], and for women, PBW = 45.5 + (0.91)[height(cm) − 152.4]. We defined low tidal volume ventilation as the prescription of an initial tidal volume of b8 mL/kg PBW. This initiative was complimentary to a pre-existing, institution-wide mechanical ventilation bundle which directs head-of-bed elevation, oral hygiene, and criteria for ventilator weaning trials designed to prevent pulmonary complications in intubated patients. The respiratory therapy manager provided structured education on the protocol at select change-of-shift times during the intervention phase. Likewise, a physician board-certified and practicing emergency medicine, pulmonology, and critical care medicine lectured to emergency medicine faculty and residents and championed protocol adoption during this same 8-month period. Both groups of clinicians were provided with just-in-time reference materials which included laminated, badge-sized cards with height versus tidal volume tables (these cards were also affixed to the ED transport ventilators), as well as disposable tape measures. In general, throughout the study, the ED respiratory therapist determines the height of the intubated patient and selects the initial tidal volume in collaboration with the emergency physician and third-year emergency medicine resident. Physicians or respiratory therapists were encouraged to tailor the respiratory rate to the acid/base status of the patient and/or decrease the tidal volume depending on clinical context or airway pressures.
2.4. Key outcome measures We chose as the primary outcome the absolute difference in mean tidal volumes among mechanically-ventilated ED patients during the periods before (2007–2014) and after (2015–2016) implementation of the low tidal volume ventilation protocol. Secondary outcomes were the proportion of ED patients with a lung-protective tidal volume (b8 mL/kg PBW) and duration of mechanical ventilation, ICU length of stay, and hospital mortality. In addition, we were interested in the impact of adherence to ED low tidal volume ventilation and subsequent delivered tidal volumes in the ICU. Specifically, we were interested in the proportion of patients receiving mechanical ventilation for at least 24 h who did not receive lung protective ventilation in the ED but subsequently had their tidal volume reduced to lung protective settings in the ICU. To evaluate these outcomes, we recorded exhaled tidal volume, respiratory rate, fraction of inspired oxygen, and positive end-expiratory pressure (PEEP), as well as static and dynamic airway pressures when available; this data was captured at three distinct time points, 1) following ED intubation (time zero [T0]), 2) at the time of ICU arrival (T1), and 3) after 24 h in the ICU (T2).
2.5. Data analysis To characterize our sample and evaluate adherence to lung protective ventilation, we used descriptive statistics to summarize ventilator settings, patient demographics and anthropometrics, and key outcome variables [duration of mechanical ventilation, length-of-stay, and hospital survival]. We also analyze secular trends in the adoption of lung protective ventilation over time, both before and after the intervention. We summarize the distribution of continuous variables using mean and standard deviation for normally-distributed data or median and interquartile range for non-normally distributed data; categorical data is summarized as proportions. We report absolute differences in group means with accompanying 95% confidence intervals for the primary study outcome and use an unpaired t-test to assess for statistical significance. We performed all data analysis using STATA version 10 (StataCorp, College Station, TX) and considered a two-tailed p value b0.05 as statistically significant.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
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Fig. 1. ED protocol for initial ventilator settings. F, frequency of respirations; IBW, ideal body weight; Ti, inspiratory time; FIO2, fraction of inspired oxygen; PEEP, positive end-expiratory pressure; PIP, peak inspiratory pressure; Pplat, end-inspiratory plateau pressure.
3. Results A total of 2959 mechanically-ventilated ED patients were included in the study (Fig. 2). Patient characteristics were similar before and after implementing the low tidal volume ventilation protocol (Table 1). Patient height was documented in the ED medical record more frequently after the intervention as compared to before (97% vs. 65% of cases, respectively, Fig. 2); height is necessary to calculate predicted body weight which is used to prescribe tidal volume according to the study protocol. The mean tidal volume (±standard deviation [SD]) delivered in the ED was 9.0 ± 1.4 mL/kg PBW before the intervention as compared to 7.2 ± 0.9 mL/kg PBW after the intervention (absolute difference 1.8 mL/kg, 95% confidence interval [CI] 1.7 to 1.9 mL/kg, p b 0.001) (Fig. 3). Similarly, the proportion of ED patients ventilated with low tidal volume ventilation (tidal volume of b8 mL/kg PBW) was higher post-intervention as compared to pre-intervention (72% versus 23%, respectively, p b 0.001)
(Table 2). A secular trend in the adoption of low tidal volume ventilation over time was not observed prior to the study intervention (Fig. 4). Considering subsequent ventilation of these patients in the ICU, a difference in mean tidal volume and the proportion of patients receiving low tidal volume ventilation was observed before and after the intervention; these differences were of a similar direction and magnitude to those observed in the ED setting (Fig. 3 and Table 2). After the intervention, a higher proportion of ED patients who initially received high tidal volumes were switched to low tidal volume ventilation in the ICU, as compared to pre-intervention (55% [118/214 patients] vs. 7% [118/1684 patients], p b 0.001). 4. Discussion The routine use of low tidal volume ventilation for the approximately 250,000 ED patients requiring mechanical ventilation may
Fig. 2. Study flow diagram.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
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Table 1 Patient characteristics and outcomes.
Table 2 Tidal volumes before and after the study intervention stratified by time point or ICU.
Characteristic
Pre-intervention period (N = 2185)
Age, mean (SD), y Male sex, N (%) Body mass index, mean (SD), kg/m2 Predicted body weight, mean (SD), kg Ratio of PaO2 to FIO2, mean (SD) ED length of stay, median (IQR), h ED disposition, N (%) Medical ICU Surgical ICU Operating room Hospital outcomes Duration of mechanical ventilation, median (IQR), d ICU length of stay, median (IQR), d Hospital length of stay, median (IQR), d Hospital mortality, N (%)
49 1465 29 68 323 1.8
(17) (67) (8) (11) (158) (1.2–2.8)
1408 (64) 674 (31) 103 (5)
Pre-intervention period (N = 2185)
Post-intervention period (N = 774) 48 535 28 69 313 1.6
(19) (69) (7) (10) (161) (1.1–2.6)
491 (63) 246 (32) 37 (5)
1.4 (0.6–4.6)
1.3 (0.5–5.3)
2.7 (1.2–7.7) 7.2 (3.3–14) 188 (9)
1.6 (0.8–4.6) 4.6 (1.7–11) 107 (14)
represent a low-effort strategy to improve the quality of ED critical care delivery. Indeed, intubated patients sometimes spend hours to days in the ED at institutions where available ICU beds can be scarce [8,12]. Early work in this area appears promising; a large, before-and-after study found that both pulmonary complications and hospital mortality decreased after adoption of a comprehensive “lung protective” ventilator protocol in the ED involving volume-targeted ventilation maintaining a plateau airway pressure b 30 cm of water, prevention of hyperoxia, and head-of-bed elevation to prevent aspiration [9]. In the current study, we observed a significant increase in the prescription of low tidal volume ventilation to intubated ED patients after implementation of a ventilator initiation protocol and focused education, as compared with historical practices in our ED. This intervention targeting emergency physicians and respiratory therapists is both feasible and durable, as the use of low tidal volumes persisted for at least the first day in the ICU, all of which should serve to reduce the likelihood of VILI among mechanically-ventilated ED patients. Several aspects of this quality improvement intervention deserve special attention. First, the ED respiratory therapists' standard work for initiating a patient on invasive mechanical ventilation underwent a foundational change, beginning with the accurate measurement of patient height using disposable tape measures stocked on the ED airway
Fig. 3. Box plots summarizing the distribution of tidal volumes before and after the low tidal volume ventilation intervention. The three time points in each period represent the tidal volume on initial ED settings, at ICU admission, and after 24 h in the ICU. The box represents the interquartile range, the vertical line inside is the median value, and the whiskers show upper and lower adjacent values for each group.
Tidal volume, mean (SD), mL/kg PBW ED initial setting ICU arrival ICU after 24 h Tidal volume, mean (SD), mL ED initial setting ICU arrival ICU after 24 h Tidal volume b8 mL/kg PBW, N (%) ED initial setting ICU after 24 h ICU tidal volume after 24 h, mean (SD), mL/kg PBW Medical ICU Surgical/trauma ICU
Post-intervention period (N = 774)
9.0 (1.4) 8.9 (1.3) 9.1 (1.4)
7.2 (0.9) 7.1 (0.9) 7.3 (0.9)
597 (74) 593 (74) 603 (73)
489 (72) 487 (71) 494 (71)
501 (23) 446 (20)
560 (72) 643 (83)
9.0 (1.4) 9.1 (1.3)
7.2 (0.9) 7.3 (0.9)
cart (height allows calculation of PBW). Before the intervention, over one-third of patients (N = 1371 or 35%) intubated in the ED did not have their height documented in the medical record and were excluded from further analysis. Anecdotally, before the intervention, clinicians frequently chose a round number for tidal volume in milliliters, typically 550 or 600 mL in an adult, which led to missed opportunities to optimize lung protection. Similarly, visual height estimation was another technique employed but it is also associated with systematic overestimation of PBW and inappropriately large tidal volumes [13]. Second, this attempt at quality improvement benefitted greatly from a physician and respiratory therapy champion; these individuals provided leadership, feedback, and tailored education to providers during and after the 8-month intervention period. We would speculate that the professional background of a clinician champion is perhaps less important than their enthusiasm and engagement. There are data to suggest ED nurses have the expertise and motivation to serve in such a capacity as well [14]. The study intervention was associated with a reduction in tidal volume of 1.8 mL/kg PBW, on average, to an absolute value of 7.2 mL/kg PBW which is consistent with current practice at other large, academic hospitals active in critical care research such as Prevention and Early Treatment of Acute Lung Injury (PETAL) network sites or the international LUNG SAFE investigators [15,16]. While an initial tidal volume ≤ 8 mL/kg PBW is desirable according to a meta-analysis [17], the utility of further reduction to 6 mL/kg PBW in ventilated patients without ARDS is controversial [18,19]. The recent PReVENT randomized trial, evaluating the effect of a low (6 mL/kg PBW) versus intermediate (b10 mL/kg) tidal volume strategy on ventilator-free days at day 28 in ICU patients without ARDS receiving mechanical ventilation, was negative for this primary outcome but also lacked any significant difference in adverse events in the two arms [20]. Interestingly, the median baseline tidal volume at randomization in the groups subsequently assigned to the low and intermediate tidal volume strategies was 7.0 and 7.3 mL/kg PBW, respectively, similar to the post-intervention cohort in the current study. We did not collect adverse event data; we suspect the observed increase in hospital mortality between the preintervention (9%) and post-intervention (14%) phases reflected secular trends in case mix and patient acuity rather than an association with the ventilator settings protocol, but this cannot be entirely excluded. Finally, perhaps a more sophisticated parameter than tidal volume indexed to lung size (i.e. PBW), such as driving pressure or mechanical power, would be better able to discriminate protective from injurious mechanical ventilation practices and could be incorporated into future ED protocols [21]. This study has several limitations. The pre-post study design is vulnerable to temporal trends in ED or ICU critical care practices which may have influenced prescribed tidal volume apart from the study
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026
M.E. Prekker et al. / American Journal of Emergency Medicine xxx (xxxx) xxx
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Fig. 4. Annual proportion of intubated ED patients receiving low tidal volume ventilation.
quality improvement intervention. However, our analysis for secular changes in tidal volume during the entire study period did not support this (Fig. 4). We did not study pulmonary complications such as the development of ARDS, pneumonia, incident pneumothorax, patientventilator dyssynchrony, or use of sedation/paralysis during the study period which precludes any comment on patient-centered outcomes associated with the observed reduction in delivered tidal volume. Furthermore, airway pressures such as the plateau pressure were not systemically recorded in the ED during the study period to corroborate the speculative benefit of reducing tidal volume in this population. The single-center design and exclusion of the few patients on nonvolume-targeted ventilator modes may limit the generalizability of our findings to other settings or ED ventilator strategies. 4.1. Conclusions This pre-post study demonstrates that implementation of a low tidal volume ventilation protocol to guide initial mechanical ventilation settings, accompanied by focused education for physicians and respiratory therapists, was feasible and associated with a significant reduction in tidal volume among intubated ED patients. Protocol deployment in the ED also appeared to positively influence delivered tidal volume in the ICU. This is important as many hospitals have reported limited penetrance of lung protective ventilation strategies in intubated patients at risk for or meeting the diagnostic criteria for ARDS [22]. The quality improvement process described here may serve as a guide for other institutions who seek to reduce variability in the prescription of mechanical ventilation and protect the lungs from iatrogenic injury. References [1] Slutsky AS, Ranieri VM. Ventilator-induced lung injury. N Engl J Med 2013;369(22): 2126–36. [2] Fuller BM, Mohr NM, Hotchkiss RS, Kollef MH. Reducing the burden of acute respiratory distress syndrome: the case for early intervention and the potential role of the emergency department. Shock 2014;41(5):378–87. [3] Weingart SD. Managing initial mechanical ventilation in the emergency department. Ann Emerg Med 2016;68:614–7. [4] Mosier JM, Hypes C, Joshi R, Whitmore S, Parthasarathy S, Cairns CB. Ventilator strategies and rescue therapies for management of acute respiratory failure in the emergency department. Ann Emerg Med 2015;66:529–41.
[5] Stephens RJ, Siegler JE, Fuller BM. Mechanical ventilation in the prehospital and emergency department environment. Respir Care 2019;64(5):595–603. [6] Kilickaya O, Gajic O. Initial ventilator settings for critically ill patients. Crit Care 2013; 17(2):123–4. [7] Fuller BM, Mohr NM, Miller CN, et al. Mechanical ventilation and ARDS in the ED: a multicenter, observational, prospective, cross-sectional study. Chest 2015;148(2): 365–74. [8] Wilcox SR, Richards JB, Fisher DF, Sankoff J, Seigel TA. Initial mechanical ventilator settings and lung protective ventilation in the ED. Am J Emerg Med 2016;34(8): 1446–51. [9] Fuller BM, Ferguson IT, Mohr NM, et al. Lung-protective ventilation initiated in the emergency department (LOV-ED): a quasi-experimental, before-after trial. Ann Emerg Med 2017;70:406–18. [10] Beitler JR, Ghafouri TB, Jinadasa SP, et al. Favorable neurocognitive outcome with low tidal volume ventilation after cardiac arrest. Am J Respir Crit Care Med 2017; 195(9):1198–206. [11] Sjoding MW, Gong MN, Haas CF, Iwashyna TJ. Evaluating delivery of low tidal volume ventilation in six ICUs using electronic health record data. Crit Care Med 2019;47(1):56–61. [12] Hung SC, Kung CT, Hung CW, et al. Determining delayed admission to intensive care unit for mechanically ventilated patients in the emergency department. Crit Care 2014;18(4):485. [13] Sasko B, Thiem U, Christ M, Trappe HJ, Ritter O, Pagonas N. Size matters: an observational study investigating estimated height as a reference size for calculating tidal volumes if low tidal volume ventilation is required. PLoS One 2018;13(6):e0199917. [14] Cornish S, Wynne R, Klim S, Kelly AM. Protective lung strategies: a cross sectional survey of nurses' knowledge and use in the emergency department. Australas Emerg Nurs J 2017;20(2):87–91. [15] Lanspa MJ, Gong MN, Schoenfeld DA, et al. Prospective assessment of the feasibility of a trial of low-tidal volume ventilation for patients with acute respiratory failure. Ann Am Thorac Soc 2019;16:356–62. [16] Belani G, Laffey JG, Pham T, et al. Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries. JAMA 2016;315:788–800. [17] Neto AS, Simonis FD, Barbas CS, et al. Lung-protective ventilation with low tidal volumes and the occurrence of pulmonary complications in patients without acute respiratory distress syndrome: a systematic review and individual patient data analysis. Crit Care Med 2015;43(10):2155–63. [18] Ferguson ND. Low tidal volumes for all? JAMA 2012;308:1689–90. [19] Bonatti G, Robba C, Ball L, Silva PL, Rocco PRM, Pelosi P. Controversies when using mechanical ventilation in obese patients with and without acute respiratory distress syndrome. Expert Rev Respir Med 2019;13(5):471–9. [20] Simonis FD, Serpa Neto A, Binnekade JM, et al. Effect of a low vs intermediate tidal volume strategy on ventilator-free days in intensive care unit patients without ARDS: a randomized clinical trial. JAMA 2018;320:1872–80. [21] Tonetti T, Vasques F, Rapetti F, et al. Driving pressure and mechanical power: new targets for VILI prevention. Ann Transl Med 2017;5:286. [22] Umoh NJ, Fan E, Mendez-Tellez PA, et al. Patient and intensive care unit organizational factors associated with low tidal volume ventilation in acute lung injury. Crit Care Med 2008;36:1463–8.
Please cite this article as: M.E. Prekker, C. Donelan, S. Ambur, et al., Adoption of low tidal volume ventilation in the emergency department: A quality improvement interven..., American Journal of Emergency Medicine, https://doi.org/10.1016/j.ajem.2019.06.026