Trauma is a global phenomenon. In 2008, 5.1 million people (9% of total deaths) died worldwide as a result of injury. Injuries also account for 17% of the disease burden in adults aged 15–59 years in 2004 [1
Most deaths are caused by unintentional injuries including blunt trauma such as falls or road accidents. Blunt trauma accounts for an estimated 50% of the mechanism of injury proportion [1
The assessment of the hemodynamic (HD) status in blunt trauma patients is vital for early identification and timely management of a potential hemorrhage to keep the time between injury and intervention to a minimum. In order to improve trauma care furthermore, evidence-based practice guidelines are designed and implemented in every hospital. These management schemes are often based on the presence or absence of HD stability, proposed by the American College of Surgeons Advanced Trauma Life Support (ATLS) guidelines [3
When the patient is unstable, time is a luxury and immediate surgical intervention in combination with resuscitation is mandatory [4
]. When the patient is stable, more time is available for the assessment of the patient’s injuries.
Systolic blood pressure (SBP) and heart rate (HR) have traditionally been used for recognition of the shock state in ATLS and Prehospital Trauma Life Support (PTLS) guidelines [3
]. However, the value of these vital signs and their cut-off points have been disputed by some [7
Despite the importance of the HD status of blunt trauma patients, several hemodynamic parameters [e.g., HR, respiratory rate (RR), blood pressure (BP), SPB and Revised Trauma Score (RTS)] with different cut-off points are used without general consensus about the best evidence-based practice. A combination of the traditional signs BP and HR, named Shock Index (SI) (calculated by HR/SBP), has been shown to identify beginning hemorrhage [13
], need for massive transfusion [14
] and predicting mortality [11
] more early and better than the vital signs apart.
As the initial assessment of a trauma patient concerns a multidisciplinary approach by the examining anesthesiologist, trauma surgeon and the emergency physician in the emergency room, it is important for everyone to speak the same language. Different specialities, however, bring different opinions about the best treatment if there is no clear consensus about the interpretation of all parameters. The meaning of HD instability in trauma patient is still very wide with unclear borders and lacks a clear validated definition that states which indicative parameters to use to initially assess the circulatory status.
This study assesses the definitions used for HD stability in a systematic review of the literature combined with a survey of the interpretations of HD instability in blunt trauma patients in the ER amongst Dutch trauma team members in order to establish the level of consensus about HD stability for blunt trauma patients.
During the early assessment, the trauma team needs to triage blunt trauma patients according to their HD status in order to choose the best treatment pathway determined by evidence-based research. With multiple specialties featuring in current trauma teams, a multidisciplinary approach will only benefit the treatment of a trauma patient if the interdisciplinary differences in language are settled, especially in moments when time is scarce. Our systematic review and analyses of a survey amongst Dutch TTM has showed that there is a lack of consensus about which parameters and their corresponding cut-off points to use for the judgement of HD instability. If a definition of HD instability is even given in the literature, there are clear differences in the used parameters and corresponding cut-off points. There is high inter- and intra-variability between and amongst the different specialties featuring in their trauma team. This study also shows differences in parameters used for HD stability definition between current literature and TTM in The Netherlands.
To create a uniform language, research is performed to create consensus-based guidelines with clear treatment paths for blunt trauma patients. The lack of consensus about parameters and cut-off points in literature could create difficulties in making population-based conclusions for the evidence-based practice since study groups in literature are not fully comparable.
In the attempt to make uniform policy within the trauma team consisting of a trauma surgeon, anesthesiologist and emergency physician, the evaluation of trauma patients in the Dutch emergency ward is organized according to the ATLS principles. The ATLS guideline uses the term hemorrhagic shock (often used as alternative for hemodynamic instability) based on the percentage or amount of blood loss, which would correspond with a certain increase of HR, RR and a certain decrease in SBP, urinary output and Glasgow Coma Scale. The validity of this classification is, however, under debate [7
]. An online survey conducted by Mutschler et al. amongst 383 ATLS course directors and instructors confirms the doubts over the ATLS classification of shock. They showed that although the “A, B, C, D, E” approach is widely implemented, the general opinion is that only a limited number of patients can be classified by the current ATLS classification of shock. Furthermore, only 10.9% considered the ATLS classification of hypovolemic shock as a ‘good guide’ for fluid resuscitation and blood product transfusion, whereas 45.1% stated that this classification only ‘may help’ or has ‘no impact’ to guide resuscitation strategies [83
Bland et al. already showed the difficulties in judging the HD status of critically ill patients back in 1985. They state that traditional abnormal vital parameters might not be sufficient to define HD instability. They state that even when vital signs are normal, some patients can have concealed deficiencies in tissue oxygenation [84
Up till today HD stability is based on clinical gestalt. Clinical gestalt by itself is known to be a poor predictor for massive transfusion, or death in trauma patients, with sensitivity as low as 66% [85
]. Several scoring systems have been developed to create a uniform definition for HD instability based on hemodynamic parameters and their ability to predict mortality or massive transfusion.
Meredith et al. devised the first scoring system, ‘Hemodynamic Instability Score’ (HIS), in 1994 to aid management of blunt hepatic trauma because of the large portion of unnecessary laparotomies. The scoring system was based on hypotension defined as SBP below 100 mmHg and response to initial resuscitation and need for ongoing fluid resuscitation [86
]. Moore et al. [87
] noted that continuing considerable variability in the definitions of HD instability and the lack of a validated scoring system. They modified the HIS by changing the cut-off point of SBP to lesser than 90 mmHg, adding tachycardia as greater than 130 bpm and response to initial advanced trauma life support recommended volume loading and the need for ongoing resuscitation including PRBC transfusion. This classification is, however, still to be validated in prospective studies.
Other, more recent, scoring systems for prediction of massive transfusion (MT), which partly includes prediction of persistent hemodynamic instability, such as the TASH [88
], ABC [89
] and the revised MTS score [90
] use similar, or include more hemodynamic parameters as the parameters used in the HIS score. The TASH score weighs different hemodynamic parameters with several laboratory values, whereas the ABC score relies purely on hemodynamic parameters and the outcome of the FAST-echo. The revised MTS score uses only SBP as a vital parameter combined with temperature and several laboratory values based on the triangle of death in trauma patients (hypothermia, coagulopathy and metabolic acidosis).
Brockamp et al. reviewed several of these scoring systems, including the TASH and the ABC. The results, interestingly enough, showed that the only two scoring systems (TASH and PWH/Rainer) that used base deficit (BD) as a surrogate for hypoperfusion, showed the highest overall accuracy in predicting ongoing hemorrhage and MT [91
Another study by Mutschler et al. [92
], suggests the usefulness of BD in the ED. Based on a retrospective study that included over 16,000 patients from the Trauma Register DGU®
, they proposed a shock classification based on the levels of BD on ED admission. The found that their four proposed classes of worsening of BD seems to predict transfusion requirements and mortality more significantly more accurate than the current groups in the ATLS classification. BD might be a relevant clinical approach to early risk-stratify severely injured patients in the state of hypovolemic shock and for blood product transfusion during initial assessment.
As mentioned before SI has been developed and an abnormal SI values have showed to be a better predictor for transfusion and mortality in trauma patients than the vital signs apart [11
]. Recently Joseph et al. describe a DSI (SI–ER–SI-Field) in which they showed that a positive delta SI (DSI) is a better predictor for mortality (13.3%) in trauma patients compared to mortality when patients have a normal/negative DSI (9.6%). They conclude that a DSI >0.1 is associated with a higher chance of death (hazard ratio [95% CI] = 1.36 [1.29–1.45]) [93
As the higher prediction of mortality by the decreasing SI over time showed, it is important to realize that HD instability is difficult to assess based on a single point measurement. Clinical guidelines that use development of the vital signs over a period of time to suggest a condition of HD instability will be the more preferred option, since the effects of resuscitation will also have to be awaited.
Which baseline parameters should be used define HD instability remains a point of debate. Many articles have been published describing hemodynamic parameters and their ability to predict mortality. When reviewing several HD scoring systems in combination with our literature search, a possible modification should be proposed by adding instability measured by combination of the change in SBP and HR from the field into the ER, calculated as the DSI. Another option is to add hemoglobin levels as some authors suggest or use the indicative value of hemoglobin level at admission, a drop of hemoglobin in the emergency bay after volume therapy or inadequate increase of hemoglobin after PRBC transfusion. Also base excess should be implemented in this system as proposed by Mutschler et al. [92
]. The lack of consensus about the consequences of a positive FAST on the judgement of the HD status of the patient makes that this item should be left out of a scoring system, although the FAST is a vital part in the trauma screening. This modified HD scoring system should be easy to calculate and time to obtain results should be kept to a minimum in order to quickly establish the HD status of the trauma patient. It is important to realize that these systems are indicative and will only indicate a patient at risk for HD instability. With the current lack of consensus as this study shows and with the heterogeneity of the trauma patient population, combined with the low sensitivity of the clinical gestalt, a valid scoring system should be to focus of future guidelines.