Prehospital fluid resuscitation of known or suspected traumatic brain injury

Severe traumatic brain injury and hypotension is a frequent and lethal combination in multiple trauma patients in mountain areas - an analysis of the prospective international Alpine Trauma Registry

BACKGROUND

Hypotension is associated with worse outcome in patients with traumatic brain injury (TBI) and maintaining a systolic blood pressure (SBP) ≥110 mmHg is recommended. The aim of this study was to assess the incidence of TBI in patients suffering multiple trauma in mountain areas; to describe associated factors, treatment and outcome compared to non-hypotensive patients with TBI and patients without TBI; and to evaluate pre-hospital variables to predict admission hypotension.

METHODS

Data from the prospective International Alpine Trauma Registry including mountain multiple trauma patients (ISS ≥ 16) collected between 2010 and 2019 were analysed. Patients were divided into three groups: 1) TBI with hypotension, 2) TBI without hypotension and 3) no TBI. TBI was defined as Abbreviated Injury Scale (AIS) of the head/neck ≥3 and hypotension as SBP < 110 mmHg on hospital arrival.

RESULTS

A total of 287 patients were included. Fifty (17%) had TBI and hypotension, 92 (32%) suffered TBI without hypotension and 145 (51%) patients did not have TBI. Patients in group 1 were more severely injured (mean ISS 43.1 ± 17.4 vs 33.3 ± 15.3 vs 26.2 ± 18.1 for group 1 vs 2 vs 3, respectively, p < 0.001). Mean SBP on hospital arrival was 83.1 ± 12.9 vs 132.5 ± 19.4 vs 119.4 ± 25.8 mmHg (p < 0.001) despite patients in group 1 received more fluids. Patients in group 1 had higher INR, lower haemoglobin and lower base excess (p < 0.001). More than one third of patients in group 1 and 2 were hypothermic (body temperature < 35 °C) on hospital arrival while the rate of admission hypothermia was low in patients without TBI (41% vs 35% vs 21%, for group 1 vs 2 vs 3, p = 0.029). The rate of hypothermia on hospital arrival was different between the groups (p = 0.029). Patients in group 1 had the highest mortality (24% vs 10% vs 1%, p < 0.001).

CONCLUSION

Multiple trauma in the mountains goes along with severe TBI in almost 50%. One third of patients with TBI is hypotensive on hospital arrival and this is associated with a worse outcome. No single variable or set of variables easily obtainable at scene was able to predict admission hypotension in TBI patients.

Permissive hypotension/hypotensive resuscitation and restricted/controlled resuscitation in patients with severe trauma

Achieving a balance between organ perfusion and hemostasis is critical for optimal fluid resuscitation in patients with severe trauma. The concept of “permissive hypotension” refers to managing trauma patients by restricting the amount of resuscitation fluid and maintaining blood pressure in the lower than normal range if there is continuing bleeding during the acute period of injury. This treatment approach may avoid the adverse effects of early, high-dose fluid resuscitation, such as dilutional coagulopathy and acceleration of hemorrhage, but does carry the potential risk of tissue hypoperfusion. Current clinical guidelines recommend the use of permissive hypotension and controlled resuscitation. However, it is not mentioned which subjects would receive most benefit from this approach, when considering factors such as age, injury mechanism, setting, or the presence or absence of hypotension. Recently, two randomized clinical trials examined the efficacy of titrating blood pressure in younger patients with shock secondary to either penetrating or blunt injury; in both trials, overall mortality was not improved. Another two major clinical trials suggest that controlled resuscitation may be safe in patients with blunt injury in the pre-hospital setting and possibly lead to improved outcomes, especially in patients with pre-hospital hypotension. Some animal studies suggest that hypotensive resuscitation may improve outcomes in subjects with penetrating injury where bleeding occurs from only one site. On the other hand, hypotensive resuscitation in blunt trauma may worsen outcomes due to tissue hypoperfusion. The influence of these approaches on coagulation has not been sufficiently examined, even in animal studies. The effectiveness of permissive hypotension/hypotensive resuscitation and restricted/controlled resuscitation is still inconclusive, even when examining systematic reviews and meta-analyses. Further investigation is needed to elucidate the effectiveness of these approaches, so as to develop improved treatment strategies which take into account coagulopathy in the pathophysiology of trauma.

The Impact of Pre-Hospital Administration of Lactated Ringer's Solution versus Normal Saline in Patients with Traumatic Brain Injury

Lactated Ringer's (LR) and normal saline (NS) are both used for resuscitation of injured patients. NS has been associated with increased resuscitation volume, blood loss, acidosis, and coagulopathy compared with LR. We sought to determine if pre-hospital LR is associated with improved outcome compared with NS in patients with and without traumatic brain injury (TBI). We included patients receiving pre-hospital LR or NS from the PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study. Patients with TBI (Abbreviated Injury Scale [AIS] head ≥3) and without TBI (AIS head ≤2) were compared. Cox proportional hazards models including Injury Severity Score (ISS), AIS head, AIS extremity, age, fluids, intubation status, and hospital site were generated for prediction of mortality. Linear regression models were generated for prediction of red blood cell (RBC) and crystalloid requirement, and admission biochemical/physiological parameters. Seven hundred ninety-one patients received either LR (n = 117) or NS (n = 674). Median ISS, AIS head, AIS extremity, and pre-hospital fluid volume were higher in TBI and non-TBI patients receiving LR compared with NS (p < 0.01). In patients with TBI (n = 308), LR was associated with higher adjusted mortality compared with NS (hazard rate [HR] = 1.78, confidence interval [CI] 1.04-3.04, p = 0.035). In patients without TBI (n = 483), no difference in mortality was demonstrated (HR = 1.49, CI 0.757-2.95, p = 0.247). Fluid type had no effect on admission biochemical or physiological parameters, 6-hour RBC, or crystalloid requirement in either group. LR was associated with increased mortality compared with NS in patients with TBI. These results underscore the need for a prospective randomized trial comparing pre-hospital LR with NS in patients with TBI.

Goal-directed resuscitation in the prehospital setting: a propensity-adjusted analysis

BACKGROUND

The scope of prehospital (PH) interventions has expanded recently--not always with clear benefit. PH crystalloid resuscitation has been challenged, particularly in penetrating trauma. Optimal PH crystalloid resuscitation strategies remain unclear in blunt trauma as does the influence of PH hypotension. The objective was to characterize outcomes for PH crystalloid volume in patients with and without PH hypotension.

METHODS

Data were obtained from a multicenter prospective study of blunt injured adults transported from the scene with ISS > 15. Subjects were divided into HIGH (>500 mL) and LOW (≤500 mL) PH crystalloid groups. Propensity-adjusted regression determined the association of PH crystalloid group with mortality and acute coagulopathy (admission International Normalized Ratio, >1.5) in subjects with and without PH hypotension (systolic blood pressure [SBP], <90 mm Hg) after controlling for confounders.

RESULTS

Of 1,216 subjects, 822 (68%) received HIGH PH crystalloid and 616 (51%) had PH hypotension. Initial base deficit and ISS were similar between HIGH and LOW crystalloid groups in subjects with and without PH hypotension. In subjects without PH hypotension, HIGH crystalloid was associated with an increase in the risk of mortality (hazard ratio, 2.5; 95% confidence interval [95% CI], 1.3-4.9; p < 0.01) and acute coagulopathy (odds ratio [OR], 2.2; 95% CI, 1.01-4.9; p = 0.04) but not in subjects with PH hypotension. HIGH crystalloid was associated with correction of PH hypotension on emergency department (ED) arrival (OR, 2.02; 95% CI, 1.06-3.88; p = 0.03). The mean corrected SBP in the ED was 104 mm Hg. Each 1 mm Hg increase in ED SBP was associated with a 2% increase in survival in subjects with PH hypotension (OR, 1.02; 95% CI, 1.01-1.03; p < 0.01).

CONCLUSION

In severely injured blunt trauma patients, PH crystalloid more than 500 mL was associated with worse outcome in patients without PH hypotension but not with PH hypotension. HIGH crystalloid was associated with corrected PH hypotension. This suggests that PH resuscitation should be goal directed based on the presence or absence of PH hypotension.