This monocentric prospective observational study was conducted from October 2016 to April 2018 in the ED of Lausanne University Hospital in the State of Vaud, Western Switzerland (~794,000 inhabitants in 2017). This Level-1 trauma centre has 1400 beds, and its ED provides 42,000 consultations per year. A unique medical dispatch centre coordinates the State’s EMS crews. Paramedics use the State protocols for autonomous intravenous access, cardiopulmonary resuscitation procedures, defibrillation and emergency medication administration (acetylsalicylic acid, adrenaline, amiodarone, clonazepam, diazepam, fentanyl, glucagon, glucose, isosorbide dinitrate, midazolam, morphine, naloxone, paracetamol, salbutamol and thiamine) [19]. The decision to use LST for transportation from the site is left to the discretion of the EMS crew [11]. Its use allows the EMS crew to break normal traffic laws but with extreme caution. As patients arrive at the hospital, ED physicians do not know if the EMS crew used LST.
All patients arriving by ambulance at the ED were eligible. Trauma patients, hospital transfers and patients under 16 years old were excluded. As we did not have the resources to follow all patients individually for the duration of the study, we used a convenience sampling method [20]. During their shifts, two research nurses and a medical student screened as many consecutive patients transported to the ED as possible.
As for trauma cases, TCHI procedures for non-trauma patients were not clearly defined or validated in the literature at the time of the study. The study team therefore adapted a list developed by Ross et al. [8] (Table 1).
Table 1: List of TCHI procedures to be performed within 15 minutes of arriving at hospital
1. Airway and/or respiratory support procedures
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Patient intubation
Mechanical ventilation
High frequency jet ventilation
Tracheostomy
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Cricothyroidotomy
Thoracocentesis
Chest tube placement
Non-invasive ventilation
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2. Invasive vascular procedures
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Central line
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Endovenous pacemaker
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Arterial line
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Embolization
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Dialysis catheter
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|
3. Intensive therapeutic medical procedures
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Cardiopulmonary resuscitation
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Extracorporeal membrane oxygenation
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Shock managment (rapid fluid administration, vasopressors)
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Emergency medication (antihypertensives, vasodilatators, antiarrhythmics, antiepileptics)
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External pacing
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Intoxication treatment – antidote administration
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Active rewarming
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Transfusion, frozen fresh plasma, Factor VIIa or prothrombin complex concentrate
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4. Fast-track
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STEMI fast-track
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OHCA fast-track
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Stroke fast-track
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Legend: STEMI: ST-elevation myocardial infarction; OHCA: out-of-hospital cardiac arrest.
The following prehospital variables were collected: gender; age; duration and distance of transport from the field; and the use of LST. Age was dichotomized (<65 vs. ≥ 65 years). In order to study those variables that may affect the delay and realization of TCHI, EMS providers were asked after each intervention if they expected TCHI to be performed. TCHI foreseen by the EMS providers was defined as “expected TCHI” and that performed was defined as “validated TCHI”. EMS providers estimated the severity of non-trauma cases using the National Advisory Committee for Aeronautics (NACA) score, which comprises eight categories ranging from 0 (no injury or disease) to 7 (lethal injuries or disease, with or without resuscitation attempts). A NACA score of ≥ 4 implies a potential life-threatening condition [21,22].
The following hospital variables were collected: time interval between arrival in the ED and the first TCHI; TCHI performed within the first 15 minutes; in-hospital length of stay (LOS); hospital mortality; and disposition after ED management in intensive care unit (ICU), intermediate care unit (IMCU) or general ward (GW). An arbitrary cut-off of 15 minutes for TCHI was chosen based on previous studies [8,15].
Data were retrieved from the patient information database that was established for this study and analysed with the Statistical Package for the Social Sciences (SPSS), version 25 (IBM Corp., Armonk, NY).
As appropriate, data were described as frequency, mean and standard deviation (SD) or median and interquartile range (IQR). Descriptive statistics were used to analyse the frequency of LST use. Univariate analysis (including Student’s t-test and Pearson’s chi-square test) and multivariate analysis (including logistic regression) were used to determine variables associated with the receipt of TCHI: patients’ age and gender; LST; NACA score; and expected TCHI. Odds ratio (OR), lower and upper confidence intervals (95%CI), sensitivity, specificity and positive and negative predictive values (PPV, NPV) were calculated. A p value of < 0.05 was considered to indicate statistical significance.