TERN Top Papers May 2021

Authors: Noel Fernando, Stephen Ojo, Lucie Cocker, Nick Tilbury, Kiara Vincent / Editors: Noel Fernando, Lucie Cocker, Rajesh Chatha, Robert Hirst / Codes: / Published: 14/05/2021

The aim of TERN Top Papers is to highlight the top emergency care related papers for emergency physicians, keeping them abreast of the latest practice-changing studies. This month we have a team of five energetic and enthusiastic emergency physicians interested in medical education and research. We have reviewed nearly 1326 papers from across the globe over the past twelve months and rated them based on various quality indicators.

The theme this month is critical care. Our papers were selected from domains like airway, ultrasound, sepsis, models of care and medications. We hope these synopses will inspire you to read the original papers and will impact upon your clinical practise.

Our team this month is:

  1. Noel Fernando ST6 EM/ICM TRAINEE, Chesterfield Royal Hospital
  2. Stephen Ojo DREEM Fellow/ ED CESR Speciality Dr at Queens Medical Centre Nottingham.
  3. Lucie Cocker Emergency Medicine ST3 at Queens Medical Centre Nottingham.
  4. Nick Tilbury Emergency Medicine ST3 at Queens Medical Centre Nottingham.
  5. Kiara Vincent ST5 Emergency Medicine trainee from the East Midlands, currently on an OOPP working pre-hospital on a new Physician Response Unit in Leicester.

Technical factors associated with first-pass success during endotracheal intubation in children: analysis of video laryngoscopy recordings 1

First-pass success (FPS) during intubation is associated with lower morbidity for paediatric patients. The aim of this paper is to use video laryngoscopy (VL) recordings and review the technical aspects of intubation, including factors associated with FPS in children.

A retrospective study of intubation attempts performed using VL in a paediatric ED between January 2014 and December 2018. Data were abstracted from a quality assurance database, the electronic medical record and VL recordings.

The primary outcome was FPS. Intubation practices were analysed using descriptive statistics. Patient and procedural characteristics associated with FPS in univariate testing and clinical factors identified from the literature were included as covariates in a multivariable logistic regression. An exploratory analysis examined the relationship between position of the glottic opening on the video screen and FPS.

The study was performed during 237 patient encounters, with 231 using video-assisted laryngoscopy. Data from complete video recordings were available for 129 attempts (59%); an additional 31 (13%) had partial recordings.

Overall, 173 (73%) of first attempts were successful. Adjusting for patient age, placing the blade tip into the vallecula (adjusted OR (aOR) 7.2 (95% CI 1.7 to 30.1)) and obtaining a grade 1 or 2a-modified Cormack-Lehane glottic view on the video laryngoscope screen (aOR 6.1 (95% CI 1.5 to 25.7) relative to grade 2b) were associated with increased FPS in the subset of patients with complete recordings.

Exploratory analysis suggested that FPS is highest (81%) and duration is shortest when the glottic opening is located in the second quintile of the video screen.

Bottom Line

Placement of the blade tip into the vallecula rather than lifting the vallecula (when using a Macintosh blade), sufficient glottic visualisation, and locating the glottic opening improves first pass success. The position of the blade tip didnt show any difference in when using a Miller blade.

While using VL, having between 20% – 40% of the screen visible above the glottic opening is advantageous. Regardless of whether the blade tip was located in the vallecula or used to lift the epiglottis, these technical factors are associated with high first pass success and reduced duration of intubation in paediatric ED.


  1. Miller K, Monuteaux M, Nagler J. Technical factors associated with first-pass success during endotracheal intubation in children: analysis of videolaryngoscopy recordings. Emerg Med J. 2020 Nov 10:emermed-2020-209700. doi: 10.1136/emermed-2020-209700. Epub ahead of print.

Airway Management in Critical Illness: An Update. Scott et al. 2

Critically ill patients often require airway management. This paper postulates that there is a difference in the periprocedural outcomes of advanced airway procedure in critical setting (ICU /ED) compared to elective intubation in the operating room.

Strategies to reduce the morbidity and mortality associated with airway management in the critically ill and unstable patients were reviewed. The update was generated from a literature search of publications from 2007 through June 2019 on PubMed, Embase, Scopus, Google Scholar and the Cochrane Library (Cochrane Collaboration). The references of articles were retrieved and were examined for relevancy.

The Authors described the inefficiency of the Mallampati score and discussed the validation of the MACOCHA score, which combines anatomic, physiologic and operator characteristics for airway assessment. A standardized approach using a checklist has been seen to improve patient safety and outcomes.

With regards to patient positioning, the sniffing position was favoured in a randomized trial and was described in detail as well as the use of adjunctive oxygen delivery devices. Some controversies concerning rapid sequence induction were highlighted, including the role of human factors. The most frequently used pharmacologic agents were revised. Finally, the authors re-reproduced an illustration on the Vortex approach as a cognitive aid for cant intubate, cant oxygenate (CICO) scenarios.

Bottom Line

As emergency doctors caring for critically ill patients, we must strive to maintain our expertise in airway management so we maintain currency. An awareness of factors that predict per-intubation mortality should guide our decision on who we decide may require intubation, ICU stay and our management decisions. This knowledge will also inform our practice and behaviour regarding procedural sedation. Physicians must maintain familiarity with pharmacological agents used and tailor their usage to different patient situations. High-fidelity simulation can help maintain skills that are used infrequently.


Critical Care Delivery Solutions in the Emergency Department: Evolving Models in Caring for ICU Boarders. Jayaprakash et al 3

This paper describes various models of how ongoing care can be provided to critically ill patient awaiting ICU beds in the ED. The authors describe situations where patients referred to ICU or a similar critical setting may remain in the emergency department for much longer than expected. Crowding in the ED is not an uncommon finding and this is not an uncommon event. This patient cohort are referred to as ICU boarders in the United States. The causes for crowding were explored. There has been an increase in ICU admissions from ED, with one study finding a 48.8% increase in ICU admissions from ED. In many EDs in the UK we are faced with similar situations where we provide care to patients who are awaiting ICU beds. The paper describes the financial, logistical and personnel burden that can arise in this situation. A number of solutions for delivering critical care in ED are proposed. These include geography-based models (expediting admission to ICU, hybrid ED-ICU, ED-ICU/RCU) and personnel-focussed models (ICU-based critical care consultation model and ED-based critical care consultation model). All these models are described in details and give consideration for their implementation, resources, features and provide examples of institution that have used each model.

Bottom Line

Emergency physicians need to be more aware of methods of providing critical care in ED. As an increasing number of the ED workforce have intensive care sub-specializations, there is a need for further information around implementation of these models. These models provide a framework for discussions around how we care for this at-risk patient cohort.


3. Jayaprakash N, Pflaum-Carlson J, Gardner-Gray J, Hurst G, Coba V, Kinni H, Deledda J. Critical Care Delivery Solutions in the Emergency Department: Evolving Models in Caring for ICU Boarders. Annals of Emergency Medicine, Volume 76, Issue 6, 2020, Pages 709-716, doi: 10.1016/j.annemergmed.2020.05.007.

Early prediction of high flow nasal cannula therapy outcomes using a modified ROX index incorporating heart rate. 4

This prospective observational cohort study assessed the use of a modified Respiratory Rate Oxygenation Index (ROX Index) (pulse-oximetry / fraction of inspired oxygen to respiratory rate) which incorporated a patients heart rate to predict success or failure in treating patients with respiratory failure with high flow nasal cannula (HFNC). Failure was defined as requiring intubation despite HFNC initiation, although those who progressed to NIV were excluded from the data rather than classified as failure.

A total of 145 patients were enrolled in this study. 99 patients (68.3%) were initiated on HFNC for acute hypoxemic respiratory failure). Pneumonia was the commonest primary diagnosis (n=87, 87.9%). The median P/F ratio was 94 (IQR 74138), and SOFA score was 4 (IQR 36) at the time of HFNC initiation.

In patients initiated on HFNC for acute respiratory failure, 98 (99.0%), 90 (90.9%), 83 (83.9%) and 67 (67.7%) patients remained free of mechanical ventilation after 2, 6, 10 and 24h respectively. 45 (45.5%) patients required intubation (HFNC failure) at a median of 16h (IQR 736) after HFNC initiation. HFNC failure was associated with a higher SOFA and APACHE II score. For the 61 patients with HFNC failure, the Kaplan-Meier plot for the probability of being free of mechanical ventilation demonstrated that patients who did not survive hospital admission had a longer duration of HFNC before intubation.

Patients with HFNC failure had a significantly lower ROX and ROX-HR index recorded at all time points, with a significantly higher heart rate observed. Within the first 12h, both indices appeared to have the highest diagnostic accuracy at 10h at predicting HFNC success, with an AUROC of 0.723 (95% confidence interval (CI) 0.6050.862) and 0.739 (95% CI 0.6260.853) for the ROX index and ROX-HR index, respectively.

Bottom Line

The ROX index allows clinicians to identify those patients for whom respiratory interventions other than intubation may be warranted but can also identify those at risk of continued deterioration without intubation. It also allows identification of those for whom intubation should be considered urgently.

This scoring tool may help emergency physicians in resus make decisions around the most appropriate treatment for patients in respiratory failure, and help looking to determine disposition. It may help prevent delays in intubation and escalation of care for those at risk of deterioration.


Effect of controlling fluid choice in the ED and ICU versus ICU only on sepsis outcomes in a clinical trial of balanced crystalloids versus saline. 5

This study is from an abstract for the American Thoracic Society conference which whether earlier treatment with balanced crystalloids (from presentation to the ED) had improved mortality against a cohort who only received balanced fluids when they were admitted to ICU.

This study was a secondary analysis of outcomes in ICU patients with sepsis in the Isotonic Solutions and Major Adverse Renal Events Trial (SMART) dataset (n=1,641). SMART was a cluster-randomized multiple-crossover trial comparing intravenous fluid administration in critically unwell adults It compared 30-day mortality for patients randomized to receive balanced crystalloids or saline. The first 7 months of the SMART trial only controlled fluid in the IUC, and the last 15 months of the SMART trial controlled fluids in the ED and ICU.

A total of 367 patients with sepsis were enrolled during the ICU only intervention period and 1,274 were enrolled during the ED & ICU intervention period. During the initial ICU-only phase, 30-day mortality in the balanced crystalloid group (n=47, 33.1%) was comparable to the saline group (n=74, 32.9%) (adjusted odds ratio 1.14, 95% CI 0.701.88). During the ED & ICU phase, 30-day mortality in the balanced crystalloid group (n=170, 24.9%) trended better than in the saline group (n=181, 30.6%) (adjusted odds ratio 0.68, 95% CI 0.520.89). The P-value for interaction was 0.07.

Bottom Line

Whilst this is a short abstract, and a retrospective secondary analysis, the topic showed promise and was included in this months TERN Top Papers. Recent work by the same group has reported the use of balanced crystalloids may decrease the incidence of death, renal replacement therapy, or persistent renal dysfunction6.

Patients admitted to the ED are not subject to the same four-hour targets as use in the ED, so the fluids chosen in the ED may be given for a more prolonged period, but given crowding and bed-waits, the findings are likely transferrable. Unless a considered choice of alternative fluids has been made due to patient presentation, we should all be moving towards balance crystalloids as the go-to fluids for patients with sepsis in the ED. If were not already!


5. Jackson K, Wang L, Casey J, Self W, Rice T, Semler M. Effect of Controlling Fluid Choice in the ED and ICU Versus ICU Only on Sepsis Outcomes in a Clinical Trial of Balanced Crystalloids Versus Saline. American Thoracic Society 2020 International Conference, 2020. [conference proceedings on the internet]. Available from https://doi.org/10.1164/ajrccm-conference.2020.201.1_MeetingAbstracts.A6309. [cited 11 May 2020]

6. Semler M, Self W, Wanderer J, Ehrenfeld J, Wang L, Byrne D, Stollings J, Kumar A, Hughes C, Hernandez A, Guillamondegui O, May A, Weavind L, Casey J, Siew E, Shaw A, Bernard G, Rice T; SMART Investigators and the Pragmatic Critical Care Research Group. Balanced Crystalloids versus Saline in Critically Ill Adults. N Engl J Med. 2018 Mar 1;378(9):829-839. doi: 10.1056/NEJMoa1711584. Epub 2018 Feb 27.


Ketamine Safety and Use in the Emergency Department for Pain and Agitation/Delirium: A Health System Experience. 7

This multi-centre, retrospective study in the US aimed to evaluate the safety of both sub-dissociative dose ketamine (SDDK) for analgesia and dissociative dose ketamine for severe agitation/excited delirium in emergency departments. The data was collected via electronic-health records from a total of 18 EDs that had all used the same standardised dosing-protocol(0.2-0.3ml/kg IV for SDDK and 4mg/kg IM for dissociative dose) and degree of monitoring.

Primary outcomes were severe respiratory adverse events (intubation, non-invasive positive pressure ventilation, use of non-rebreather mask, and/or escalation from baseline oxygen requirements to at least four litres or more per minute via NC) and severe cardiovascular adverse events (hypertension requiring IV antihypertensive or new dysrhythmia requiring electrical or medical cardioversion within 2 hours).

Secondary outcomes were adverse neuropsychiatric events, as well as the percentage of ketamine administrations that adhered to the afore-mentioned protocols.

A total of 247 ED encounters met the inclusion criteria. Serious respiratory adverse events occurred in 2 1% (2/210) of patients in the SDDK group and 16.2% (6/37) of patients in the dissociative dose group. Serious cardiovascular adverse events occurred in 0.5% (1/210) in the SDDK group and in none of the dissociative dose group. Neuropsychiatric adverse events occurred in 4.3% (9/210) of the SDDK group and in none of the dissociative dose group

Bottom Line

The study found fewer serious respiratory, cardiovascular and neuropsychiatric adverse events with both SDDK and dissociative dose ketamine use than previous single-centre studies have suggested. Though limited by the fact that the data relied on accurate recording of events at the time, the study findings supported the safety of more widespread use of ketamine in the ED.


Combining qSOFA criteria with initial lactate levels: Improved screening of septic patients for critical illness. 8

The aim of this multi-centre retrospective cohort study was to compare the performance of the qSOFA score (GCS <15 / RR > 20 / SBP <100) with the qSOFA score combined with initial lactate levels in screening septic patients for critical illness.

The primary outcome was a composite of death in hospital, the administration of vasopressors, and admission to an intensive care unit within 72 hours of initial presentation.

The study compared the screening performance of 1) initial lactate levels of >2 and >4; 2) qSOFA scores of >1, >2 and =3 and 3) combinations of these. The study recruited 2584 patients that attended with an infectious disease-related illness and had a lactate level taken within 6 hours. Of these, 465 (18%) met the criteria for the primary outcome and were identified as critically ill.

Of all the lactate and qSOFA threshold measurements or combination of measurements, a value of qSOFA >1 OR lactate >2 had the highest sensitivity at 94% (95% CI 91.3-95.9) but the lowest specificity at 37.5% (95% CI 35.5-39.6) for critical illness. The combination of qSOFA =3 AND lactate >4 had the highest specificity at 99.7% (95% CI: 99.3 to 99.9) but the lowest sensitivity at 7.1% (95% CI: 5.0 to 9.9). When contrasting the combined qSOFA and lactate ROC curve with either qSOFA or lactate alone, the combination performed significantly better (p <0.0001 for both).

Bottom Line

The combination of qSOFA >1 OR lactate >2 provides a better sensitivity for screening critical illness in septic patients than either measurement alone and may be preferable to current ED screening methods.


Evaluating the potential impact of an emergency department extracorporeal resuscitation (ECPR) program: A health records review. 9

We know patients undergoing out of hospital cardiac arrest tend to have have poor outcomes, but some recent data shows potential benefits of extracorporeal cardiopulmonary resuscitation (ECPR) in patients with refractory cardiac arrest 10. However, as a low volume and resource-intensive intervention, there are barriers to its implementation.

This study was a retrospective review of selected patients who presented with out-of-hospital cardiac arrest or ROSC to a tertiary-care academic hospital during a 2-year period. Their aim was to review the characteristics of cardiac arrest patients who presented to their ED and assess if they would meet criteria for ECPR according to current literature.

They reviewed current literature to determine favourable patient characteristics that would make them eligible for ECPR under two sets of criteria: liberal or restrictive. Both criteria included patients with no significant comorbidities. Liberal included patients with a witnessed arrest, CPR within 10 minutes, no asystole; and restrictive included immediate bystander CPR, <60min total prehospital time and initial rhythm VT/VF.

Of the 179 patients that met the study criteria, 33 (liberal) and 5 (restrictive) patients would have been candidates of ECPR.

The main limitations were the quality of the records which were reviewed manually, and the fact it was only a single centre study.

Bottom Line

ECPR is an emerging resuscitative modality that could improve survival for ED patients with refractory cardiac arrest. A distinct, small but meaningful number of ED patients could be eligible for ECPR; 640% of refractory out-of-hospital cardiac arrest patients presenting to a tertiary care ED would have been potential ECPR candidates

Institutions need a clear picture of the potential impact for ED and hospital operations before initiation of ECPR programs, and further work needs to be done to determine feasibility, cost implications, and standardised protocols for ECPR.


9. McDonald L, Mastoras G, Hickey M, McDonald B, Kwok ESH. Evaluating the potential impact of an emergency department extracorporeal resuscitation (ECPR) program: a health records review. CJEM. 2020 May;22(3):375-378. doi: 10.1017/cem.2019.472.

10. Yannopoulos D, Bartos J, Raveendran G, Walser E, Connett J et al. Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST): a phase 2, single centre, open-label, randomised controlled trial. The Lancet. 2020 December; 396(10265):1807-16. doi: 10.1016/S0140-6736(20)32338-2.


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