Injury is the leading cause of death in industrialised countries of people aged between 1 and 44 years [19, 29, 30], and trauma is the leading cause of death from 1 through 21 years of age [31]. Survival after traumatic out-of-hospital cardiopulmonary arrest in general seems to be rare in the last decades, even with maximum resuscitative efforts. Recently, a study introduced a trauma CPR algorithm and in their collective over 60 % management errors and preventable deaths were found. They concluded that the prehospital trauma management has the highest potential to improve tCPR and survival [21].
In this study we analysed data from the TR-DGU. Our patient cohort consists of victims of severe blunt trauma expressed by a median ISS of 42.2, comparable to other studies in adults on TCRA [12, 32]. Little is known about specific and significant factors during the treatment of polytraumatised patients in terms of different time points of resuscitation (preclinical, in the emergency room or at both times) with specific focus on CPR in the ER. With ample data from the TR-DGU, we have been able to analyse factors and parameters in relation to mortality and neurological outcome as well. Moreover, prognostic factors were analysed.
Mortality
The 25.6 % survivor rate after resuscitation in the ER we calculated is much higher than the 3.3 % reported in a systematic review containing a meta-analysis reporting a total of 238 survivors out of 5391 patients [13]; our study’s survivor rate is also much higher than that in a retrospective analysis reporting 5.4 % of 1114 patients surviving to hospital discharge after out-of-hospital traumatic cardiopulmonary arrest [33]. The results are similar to the 29 % survivor rate in a prospective observation study from Berlin/Germany [21].
In another study, 5.0 % of the patients underwent resuscitation during trauma room (TR) treatment [14]. In that study, the neurological outcome after only resuscitation in the ER was better than after preclinical resuscitation and after preclinical and ER resuscitation. One reason for this finding could be an optimal setting with an interdisciplinary team of specialists vs. a smaller preclinical team with normally only one physician. Another reason might be that cardiac arrest was witnessed in the ER setting in conjunction with resuscitation being initiated immediately, thus keeping the “downtime” minimal.
Moreover the highest rate of survivors was found in the group of preclinical resuscitation with 31.7 %. Unlike in the British and American paramedic systems, the emergency physician in Germany (the Notarzt) stabilises the emergency patient at the scene of the accident. The emergency physician in Germany is qualified to declare patients dead at the scene, which is not included in this study. In some countries, paramedic systems cannot declare someone dead without consulting a physician. Thus some trauma victims are transported to the trauma centre just to be declared dead by the trauma physician on call. These differences make comparison with the prehospital phase of other countries’ systems and with international studies therefore difficult.
On-scene triage is done by physicians and is based on their clinical assessment of the patient. These physicians also initiate the early treatment of haemorrhagic shock, provide respiratory assistance, manage pain and sedation, and insert chest tubes if necessary and can also use catecholamines (for sufficient cerebral perfusion, neurogenic shock, resuscitation, etc.). The results from the initial assessment of the patient's condition and those together with the patient’s response to treatment are used by the dispatching physician to find the closest and best-suited facility for the patient. This organisation ensures the availability of resources at the receiving centre and avoids unnecessary secondary transfers from an overcrowded or poorly suited institution (accessed initially because of its proximity to the trauma scene). The cohort demographics including injury patterns are typical for western countries.
Our data fail to support data from earlier investigations by Fulton et al., who emphasised that the location of arrest (on scene, transport or emergency room) and age did not correlate with survival [34]. Our cohort’s survival rates were different after preclinical resuscitation (31.7 %), resuscitation only in the ER (25.6 %), and after preclinical and ER resuscitation (4.8 %). A limitation of the study is that the patients who were dead at the scene were not included in the investigation, because these data are not available.
Our logistic regression model revealed that preclinical resuscitation followed by ISS, preclinical catecholamines, preclinical thorax drainage, coagulopathy, preclinical GCS ≤8 points, AIS thorax, abdomen and extremities ≥3 points, mild hypotension with ≤90 mmHg during the preclinical or ER treatment are strongly predictive for mortality after resuscitation in the ER, in line with findings by Pickens et al., who reported that respiratory efforts and a GCS ≥4 points at the scene have a positive influence on survival, and Durham et al., who reported the same regarding prehospital intubation [20, 35]. Fulton et al. also noted that a loss of neurological function is associated with mortality [34].
The percentage of thoracic trauma in polytrauma patients is generally quite high, ranging from 34 to 70 % [29, 36–39]. Huber-Wagner et al. observed that prehospital chest tube insertion was a strong predictor for survival. Also tension pneumothorax is known as the most common reason for definitive preventable traumatic death [17].
They therefore advised on-scene chest decompression of TCRA patients in case of the decision to initiate emergency cardiac care (ECC) [40].
In the European Resuscitation Council Guidelines for Resuscitation 2015, bilateral chest decompression is advised in the algorithm to address one of the reversible causes for resuscitation [41].
A study by Pickens et al. reported that several survivors met criteria for non-treatment according to proposed clinical guidelines, and that insufficient prehospital treatment was the result [20]. Katz et al., for example, analysed a 25 % rate of misplaced tracheal tubes by paramedics (27/108) [42]. Furthermore, Cera et al. found that the time of intubation (on-scene versus in-hospital) did not influence survival [1].
Normally, patients in a clinical setting should never be deprived of sufficient oxygen for a relevant period of time, unlike what can happen in a preclinical setting, where patients probably suffer several minutes without oxygenation before the medical staff reaches the scene. The fact that a patient requires resuscitation in a preclinical and ER setting seems to reflect the trauma’s severity and according to the literature often appears to be associated with a poor outcome.
In our investigation among 31.7 % survivors in the group of preclinical resuscitation 46 % had a good or moderate neurological outcome; after resuscitation in the ER 25.6 % survived, with 19.2 % having a GOS 4 or 5.
GOS has been documented in the TR-DGU since 2002, thus there are no GOS records for patients from 1993 to 2001. Our GOS calculation is therefore based on 38499 patients.
Reliable data describing outcomes in detail and including neurological function are rare in the literature. A recently published literature review covering 1980 to 2011 analysed the outcomes of children treated for out-of-hospital traumatic cardiopulmonary arrest who reached the clinic alive: 29 patients (57 %) were severely disabled; 3 children (6 %) moderately disabled, and 19 patients (37 %) had a normal outcome [43]. Margolin et al provide information on the GOS in six of 13 survivors (46.2 %) out of 67 patients (79.1 % blunt trauma) who had at least a satisfactory outcome as expressed by a GOS of ≥4 [32]. Other studies describe patients’ outcome data in terms of their being “neurologically intact” after TCRA: Fialka et al. observed 100 % of patients surviving with no neurological deficit (4/4, n = 38) [44], Fulton et al. 83.3 % of survivors being neurologically intact (5/6, n = 245) [34], Powell et al. 81.0 % of survivors (21/26, n = 959) [11], Stratton et al. 66.6 % (3/9, n = 79) [8], Battistella et al. 56.3 % (9/16, n = 604) [6], Branney et al. 3.9 % (34/42, n = 950) [45], and Martin et al. no neurologically intact patients (0/1, n = 110) [12].
Yanagawa et al. detected no significant differences between out-of-hospital TCRA patients with or without head injury except for the fact that the blunt traumatic patients with a head injury more often displayed a return to spontaneous circulation (ROSC). However, they observed no head-injury effect on the outcome [3]. In our investigation, a preclinical GCS ≤8 had a significant odds ratio of 2.18 in the multivariate logistic regression analysis with resuscitation in the ER as a dependent variable. Moreover, an AIS head ≥3 was a significant prognostic factor in our cross-tabulation, with a GOS 4 and 5 and resuscitation in the ER and preclinical GCS ≤8 showing a significant odds ratio of 3.886 in multivariate logistic regression analysis with GOS 1–3 as a dependent variable.
Our multivariate logistic regression revealed that injury severity, the preclinical use of catecholamines and preclinical thorax drainage, coagulopathy, a preclinical GCS ≤8, severe injuries to the thorax, abdomen and extremities, and preclinical shock in the ER are strongly predictive of resuscitation in the ER.
Sorted according to a bad prognosis with GOS 1–3, these factors were preclinical resuscitation, ISS, preclinical GCS ≤8, mild hypotension in the ER with Riva Rocchi (RR) ≤90mmHG, blood transfusion and catecholamines, and age ≥60 years.
Base deficit is a rapidly and widely available serum laboratory marker of systemic acidosis that increases with hypoxemia and/or shock. In the trauma setting, the base deficit correlates with the blood-transfusion requirement, risks of multiorgan failure and mortality in adult patients, including those with traumatic brain injury [31–33].
These findings are in line with the sparse data in the literature reporting that blood pressure = 0 [34] or low blood pressure in the field were prognostic factors [35].
Limitations
Our study has several limitations. Patients declared dead on-scene without transportation to a hospital were not recorded in the database. Moreover, only patients surviving CPR and transportation to the hospital could be included. That means that our database does not include those patients who required prehospital CPR but did not achieve ROSC. This is because the TraumaRegister DGU® was established as a tool for quality assessment in the acute care hospital. Patients who died before admission were thus not relevant to such an assessment. Furthermore, Germany maintains no documentation system that covers all trauma cases, including all prehospital deaths. Our survival rates thus do not refer to all cases with cardiac arrest after trauma but only to those cases who were admitted to the acute care hospital alive, i.e., with ROSC. This limitation and bias must be kept in mind when interpreting the surprisingly good survival rates.
This and other exclusion criteria (ISS <16 and secondarily transferred patients) were excluded. This could have biased the results.
Due to the fact that ECG data are not documented in the TR-DGU®, no information on cardiac rhythm was available. Furthermore, we had no specific information on the exact duration of chest compression in the pre- and/or in-hospital phase. According to the literature, resuscitation lasting more than 20 minutes seems to be associated with poor neurological outcome [33]. We could only analyse patients who underwent closed-chest compression on-scene or during transport and/or during treatment in the ED. The main limitation is our patient cohort’s preselection. The TR-DGU® only includes patients who have been transported to a hospital after chest compression after TCRA. This might be one reason for the relatively high survival rates compared to other studies. The group investigated in our study represents patients who had been resuscitated because of a subjective assessment by the on-scene emergency physician who perceived a relatively certain chance of survival for those patients.
