Al-Thani H, El-Menyar A, Mekkodathil A, Taha I, Mahmood S, Shunni A, Hammo AA, Al-Ani M, Asim M. Significance of a hypotensive episode following traumatic injury: A retrospective observational study. World J Crit Care Med 2025; 14(3): 104778 [DOI: 10.5492/wjccm.v14.i3.104778]
Corresponding Author of This Article
Ayman El-Menyar, Professor, Department of Surgery, Hamad Medical Corporation, Al-Rayyan Street, Doha 3050, Qatar. aymanco65@yahoo.com
Research Domain of This Article
Critical Care Medicine
Article-Type of This Article
Retrospective Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Hassan Al-Thani, Ayman El-Menyar, Ahammed Mekkodathil, Ibrahim Taha, Saeed Mahmood, Adam Shunni, Abdel Aziz Hammo, Mushreq Al-Ani, Mohammad Asim, Department of Surgery, Hamad Medical Corporation, Doha 3050, Qatar
Ayman El-Menyar, Department of Clinical Medicine, Weill Cornell Medicine, Doha 24144, Qatar
Author contributions: All authors contributed to the study design, data analysis and interpretation, and manuscript writing and approved the final manuscript; Asim M and Mekkodathil A analyzed the data, and El-Menyar A supervised and edited the manuscript.
Institutional review board statement: Ethical approval was obtained from the institutional review board (MRC-01-21-990) at the Medical Research Center, Hamad Medical Corporation (HMC), Doha, Qatar. Data was collected retrospectively and anonymously with no direct contact with the patients; therefore, a waiver of consent was granted.
Informed consent statement: A statement of informed consent was not required for this study.
Conflict-of-interest statement: Dr. El-Menyar has nothing to disclose.
Data sharing statement:
All data are presented in the manuscript. After a reasonable research request and signed data share agreement, further access needs approval from the medical research center at Hamad Medical Corporation.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ayman El-Menyar, Professor, Department of Surgery, Hamad Medical Corporation, Al-Rayyan Street, Doha 3050, Qatar. aymanco65@yahoo.com
Received: January 2, 2025 Revised: March 24, 2025 Accepted: May 7, 2025 Published online: September 9, 2025 Processing time: 199 Days and 5.1 Hours
Abstract
BACKGROUND
Early hemodynamic assessment remains crucial for proper management in trauma settings. Hypotension is a vital indication in trauma patients to be considered upon initial triaging to assess the risk of bleeding and hypovolemic shock which entails significant clinical attention during initial resuscitation.
AIM
To assess whether an initial episode of prehospital or emergency department hypotension is associated with an increased risk of morbidity and mortality in trauma patients.
METHODS
A retrospective analysis was performed to include all trauma patients hospitalized between 2011 and 2021. Hypotension was defined as a systolic blood pressure ≤ 90 mmHg in the prehospital setting or upon arrival to the hospital. Patients were classified into normotensive vs hypotensive and survivors vs non-survivors. Data was analyzed and compared, and multivariable logistic regression analysis was performed to identify the predictors of mortality.
RESULTS
Over the ten years, 17341 trauma admissions were analyzed, of which 1188 (6.9%) patients had hypotension episodes either at the scene or upon hospital arrival. Patients with hypotension were two years younger (P = 0.001) in age and were more likely to have higher pulse rate (P = 0.001), elevated shock index (P = 0.001), sustained more severe injuries, frequently required blood transfusion and laparotomy, and had higher complications and mortality rates. Multivariable regression analysis identified hypotension [adjusted odds ratio (aOR) = 2.505; 95% confidence interval (95%CI) = 1.798-3.489; P = 0.001] and acute respiratory distress syndrome (ARDS; aOR = 5.482; 95%CI = 3.297-9.116; P = 0.001) as independent predictors of mortality. Among hypotensive trauma patients, only ARDS (aOR = 3.518; 95%CI = 1.385-7.204; P = 0.006) was significantly associated with mortality.
CONCLUSION
Hypotensive episodes following trauma are associated with higher severity and mortality. The development of ARDS is an independent predictor of mortality in hypotensive trauma patients. A hypotensive episode is a warning sign and calls for aggressive, timely management following trauma.
Core Tip: Hypotension has been linked to an increased risk of mortality in trauma patients. Therefore, early diagnosis of the cause of bleeding and shock is crucial for hemodynamic optimization. There is a strong correlation between the need for surgery and a single episode of hypotension recorded during initial resuscitation. Shock or hypotension is an important sign of physiological deterioration that poses a significant risk of morbidity and mortality among young trauma patients. Acute respiratory distress syndrome is an independent predictor of mortality in hypotensive trauma patients. Hence, it is essential to consider a single episode of acute hypotension during triage, as this may prove physiologically detrimental with impaired organ perfusion and the worst outcome in trauma patients. Therefore, patients with a tendency to experience hypotensive episodes should be closely monitored.
Citation: Al-Thani H, El-Menyar A, Mekkodathil A, Taha I, Mahmood S, Shunni A, Hammo AA, Al-Ani M, Asim M. Significance of a hypotensive episode following traumatic injury: A retrospective observational study. World J Crit Care Med 2025; 14(3): 104778
The early hemodynamic assessment is crucial for promptly identifying and managing critically ill patients. Evidence-based management of polytrauma patients necessitates an evaluation of hemodynamic status to guide early and appropriate hemostatic resuscitation[1]. Notably, hypotension is a crucial indication in trauma patients to be considered upon initial triaging to assess the risk of bleeding and hypovolemic shock, both at the scene and upon hospital arrival[2,3]. Previous studies have referred to hypotension as documentation of a systolic blood pressure (SBP) measurement lower than 90 mmHg at any given point of time post-injury[2,4,5]. This criterion serves as a crucial indicator of hypotension and inadequate organ perfusion, which entails significant clinical attention during initial resuscitation. Interestingly, some patients may present with hypotensive at the accident scene but arrive with normal blood pressure to the emergency department (ED) and vice versa[6]. Variation in blood pressure between the accident scene and the ED may depend upon physiological stress responses, pain, or medical interventions, which may influence hemodynamic status upon arrival at the hospital.
Of note, hypotension has been linked to an increased risk of mortality in trauma patients. So, early diagnosis of the cause of bleeding and shock is crucial for hemodynamic optimization[3,7]. An earlier investigation of trauma patients found a strong correlation between the need for surgery and even a single episode of hypotension recorded during initial resuscitation[8]. Particularly, traumatic brain injury (TBI) patients with combined hypotension and hypoxia had a two-fold higher risk of mortality as compared to those who developed either hypotension or hypoxia post-injury[7]. Hypotension in patient with TBI may occur independently of bleeding, resulting from severe myocardial depression after massive catecholamine release or from herniated brainstem with damage to medullary and hypothalamic structures[9].
Furthermore, patients who developed prehospital hypotension are more likely to have greater severity of injury, necessitate emergent abdominal surgeries and mechanical ventilation, require frequent blood transfusion, and have prolonged hospital courses, including extended stays in the intensive care unit (ICU)[10-12]. Therefore, the current literature suggested a link between time-based physiological alterations associated with shock, circulatory dysfunction, and their impact on the patient outcome[13]. We hypothesize that early hypotensive episodes would be associated with worse outcomes in trauma patients. The present study aims to assess whether an initial episode of prehospital or ED hypotension is associated with an increased risk of morbidity and mortality in trauma patients.
MATERIALS AND METHODS
A retrospective analysis was conducted to include all trauma patients admitted to the Hamad Trauma Center (HTC), the only designated level I trauma center in Qatar, between January 2011 and April 2021. Data were retrieved from the Qatar National Trauma Registry, a comprehensive database encompassing nationwide information on trauma patients. This database includes all hospitalized trauma patients' prehospital, in-hospital, and rehabilitation details. Moreover, the data are regularly validated and linked to the National Trauma Data Bank (NTDB) in the United States and the Trauma Quality Improvement Program of the American College of Surgery[14]. All patients with traumatic injuries admitted to HTC were included to assess the presence of hypotension in the prehospital setting or upon arrival to the trauma room. The study excluded patients who died before arrival at the hospital and those treated and discharged from the ED or who were not registered under trauma services. Exclusion criteria also included the pediatric population, pregnant ladies, and missing relevant data such as prehospital blood pressure. The primary outcomes were in-hospital mortality and hospital length of stay (LOS). We hypothesized that prehospital hypotensive episodes are associated with worse outcomes following trauma.
The collected data included demographics (age, gender), initial vital signs such as pulse, SBP, diastolic blood pressure, shock index at the scene and trauma resuscitation unit at the ED, and associated injuries (head, chest, abdomen, pelvis). Injury characteristics such as injury severity score (ISS), Glasgow Coma score (GCS), and abbreviated injury scores (AIS) for different body regions such as head, chest, and abdomen were also collected. Also, the data included the need for blood transfusion, activation of massive transfusion protocol (MTP) in-hospital complications [acute respiratory distress syndrome (ARDS), ventilator-associated pneumonia (VAP), and sepsis], ventilator days, length of hospital and ICU stay, and mortality.
Hypotension was defined as an episode of SBP < 90 mmHg either in both prehospital settings or upon arrival to the trauma resuscitation unit[7,12]. The shock index was calculated by dividing heart rate by SBP[15]. ARDS was defined as the development of hypoxemia PaO2/FIO2 < 200, FiO2 0.8-1.0, positive end-expiratory pressure ≥ 5 cm H2O, and bilateral pulmonary infiltrates that are not entirely caused by cardiac failure[16]. Data were anonymously and retrospectively collected without direct patient contact; therefore, a waiver of consent was granted from the medical research center at Hamad Medical Corporation, Doha, Qatar (MRC-01-21-437).
Statistical analysis
Data were presented as counts (percentages), mean (SD), or medians (range) whenever appropriate. Patients were classified into normotensive and hypotensive groups, and their characteristics, management, complications, and outcomes were compared. Similarly, data for survivors and non-survivors were analyzed for all the patients, and a sub-analysis was performed to compare the outcome in the hypotensive group alone. The χ2 test was performed to compare categorical variables in two groups, whereas the Student’s t-test was used for continuous variables. Mann-Whitney U-test was used for non-parametric data whenever applicable. Univariate analysis was performed to obtain the optimum threshold value of SBP, which is associated with an increased mortality risk. Multivariable logistic regression analysis (model I) was performed for the predictors of mortality after adjusting for the most relevant covariates, such as age, gender, hypotension, ED shock index, ISS, ED GCS, blood transfusion, sepsis, and ARDS. Another multivariable logistic regression analysis (model II) was performed on a subset of trauma patients who developed hypotension using the same covariates to identify independent predictors of mortality. Data was presented as an unadjusted and adjusted odds ratio (aOR) along with a 95% confidence interval (95%CI). A two-tailed P value < 0.05 was considered statistical significant. Data analysis was carried out using the Statistical Package for Social Sciences version 21 (SPSS Inc., Chicago, IL).
RESULTS
Over the 10 years period, there were a total of 17341 trauma admissions, of which 1188 (6.9%) patients had an episode of hypotension either at the scene or after arrival at the hospital. Table 1 demonstrates the demographic and clinical characteristics of all included patients, long with a comparative analyses based on the hemodynamic status (i.e., normotensive vs hypotensive). Most patients were males (90%) with a mean age of 32.3 ± 15.6 years.
Table 1 Demographics and clinical characteristics of trauma patients based on hemodynamic status (January 01, 2011 to April 30, 2021).
Overall (n = 17341)
Normotensive (n = 16153)
Hypotensive (n = 1188)
P value
Age
32.3 ± 15.6
32.4 ± 15.6
30.5 ± 15.9
0.001
Males
15596 (89.9)
14559 (90.1)
1037 (87.3)
0.002
Vital signs at scene
Pulse rate
92.8 ± 21.2
92.3 ± 20.5
99.1 ± 27.9
0.001
SBP
130.8 ± 23.2
132.6 ± 21.4
106.3 ± 30.9
0.001
DBP
81.7 ± 18.4
82.6 ± 17.3
69.9 ± 26.3
0.001
GCS
15 (3-15)
15 (3-15)
14 (3-15)
0.001
Shock index
0.73 ± 0.23
0.71 ± 0.19
1.00 ± 0.43
0.001
Vital signs at ED
Pulse rate
91.6 ± 20.5
90.5 ± 19.5
107.3 ± 27.5
0.001
SBP
126.7 ± 20.9
128.9 ± 18.6
91.4 ± 22.2
0.001
DBP
77.1 ± 14.7
78.3 ± 13.6
57.7 ± 16.9
0.001
GCS
15 (3-15)
15 (3-15)
14 (3-15)
0.001
Shock index (n = 16622)
0.75 ± 0.26
0.72 ± 0.19
1.25 ± 0.52
0.001
Injury severity score
12.4 ± 9.5
11.7 ± 8.9
21.8 ± 13.6
0.001
Head AIS
3.4 ± 0.9
3.3 ± 0.9
3.9 ± 1.0
0.001
Chest AIS
2.7 ± 0.7
2.6 ± 0.7
3.0 ± 0.8
0.001
Abdomen AIS
2.5 ± 0.9
2.4 ± 0.8
2.9 ± 1.0
0.001
Intubation
3199 (18.4)
2461 (15.2)
738 (62.1)
0.001
Exploratory laparotomy
892 (5.1)
628 (3.9)
264 (22.2)
0.001
Blood transfusion
3052 (17.6)
2259 (14.0)
793 (66.8)
0.001
Blood units transfused
4 (1-79)
3 (1-79)
7 (1-73)
0.001
MTP activation
635 (3.6)
254 (1.6)
381 (32.1)
0.001
VAP
645 (3.7)
521 (3.2)
124 (10.4)
0.001
Sepsis
269 (1.6)
212 (1.3)
57 (4.8)
0.001
ARDS
135 (0.8)
86 (0.5)
49 (4.1)
0.001
Ventilator days
4 (1-180)
4 (1-180)
4 (1-115)
0.52
ICU LOS
4 (1-161)
4 (1-161)
5 (1-115)
0.001
Hospital LOS
5 (1-505)
5 (1-505)
8 (1-360)
0.001
Mortality
649 (3.7)
323 (2.0)
326 (27.4)
0.001
Patients with hypotension were two years younger (P = 0.001) and had higher pulse rate (P = 0.001) and shock index (P = 0.001) than the normotensive patients (Table 1). Moreover, the hypotensive patients sustained more severe injuries, as indicated by higher ISS (P = 0.001), head AIS (P = 0.001), chest AIS (P = 0.001), abdomen AIS (P = 0.001), and lower GCS when compared to the normotensive patients. Also, the rate of intubation (P = 0.001), exploratory laparotomy (P = 0.001), blood transfusion (P = 0.001), and MTP activation (P = 0.001) were higher in hypotensive patients (P = 0.001). Furthermore, the rates of in-hospital complications (VAP, sepsis, and ARDS) were significantly higher in the hypotensive cohort when compared with the normotensive group in addition to prolonged ICU LOS (P = 0.001) and hospital stay (P = 0.001). The overall mortality rate was 3.7% in the entire cohort, and those with hypotension had a significantly higher rate of mortality (27.4% vs 2.0%, P = 0.001) than the normotensive counterpart (Figure 1 and Table 1). Nearly 19% (n = 225) of the hypotensive patients had post-cardiac arrest hypotension, with a mortality rate of 75.6%. Furthermore, the mortality rate was higher in patients with asystole (63.5%) compared to those with a shockable rhythm (36.5%).
Table 2 summarizes the demographics and patient characteristics of all trauma patients based on survival status. Variables associated with significant mortality were age, shock index, injury severity, and hypotension (P = 0.001 for all). Also, the rate of interventions, blood transfusion, MTP activation, and in-hospital complications was significantly higher among non-survivors than among survivors.
Table 2 Overall demographics, clinical characteristics, management, and complications based on outcome (n = 17341).
Survivors (n = 16692)
Non-survivors (n = 649)
P value
Age
32.1 ± 15.5
37.0 ± 17.9
0.001
Males
14993 (89.8)
603 (92.9)
0.01
Scene shock index
0.73 ± 0.22
0.81 ± 0.41
0.001
ED shock index
0.74 ± 0.23
1.09 ± 0.54
0.001
Hypotension
862 (5.2)
326 (50.2)
0.001
Injury severity score
11.7 ± 8.5
31.6 ± 12.5
0.001
GCS at ED
15 (3-15)
3 (3-15)
0.001
Head AIS
3.3 ± 0.9
4.5 ± 0.8
0.001
Chest AIS
2.6 ± 0.7
3.0 ± 0.8
0.001
Abdomen AIS
2.5 ± 0.9
2.9 ± 1.1
0.001
Intubation
2562 (15.3)
637 (98.2)
0.001
Exploratory laparotomy
753 (4.5)
139 (21.4)
0.001
Craniotomy/craniectomy
477 (2.9)
64 (9.9)
0.001
ORIF
3137 (18.8)
10 (1.5)
0.001
Blood transfusion
2546 (15.3)
506 (78.0)
0.001
Blood units transfused
3 (1-56)
8 (1-79)
0.001
MTP activation
382 (2.3)
253 (39.0)
0.001
Complications
ARDS
78 (0.5)
57 (8.8)
0.001
VAP
574 (3.4)
71 (10.9)
0.001
Sepsis
222 (1.3)
47 (7.2)
0.001
ICU LOS
4 (1-161)
5 (1-144)
0.04
Ventilator days
4 (1-180)
4 (1-144)
0.52
Demographics of hypotensive trauma patients
Table 3 compares the demographics, clinical characteristics, and management among hypotensive patients who survived vs non-survivors. Hypotensive patients who died were older and had significantly higher ISS, head and chest AIS scores, and ED shock index (P < 0.001 for all) in comparison to survivors.
Table 3 Comparison of demographics, clinical characteristics, management, and complications in hypotensive patients (n = 1188).
Survivors (n = 862)
Non-survivors (n = 326)
P value
Age
29.5 ± 15.5
33.9 ± 16.6
0.001
Males
738 (85.6)
299 (91.7)
0.005
Associated injuries
Head
240 (27.8)
225 (69.0)
0.001
Chest
415 (48.1)
223 (68.4)
0.001
Abdomen
368 (42.7)
160 (49.1)
0.04
Pelvis
242 (28.1)
84 (25.8)
0.42
Shock index at scene
1.01 ± 0.41
0.97 ± 0.47
0.32
Shock index at ED
1.20 ± 0.49
1.49 ± 0.58
0.001
Injury severity score
17.9 ± 11.7
31.9 ± 12.9
0.001
GCS at ED
15 (3-15)
3 (3-15)
0.001
Head AIS
3.3 ± 0.9
4.4 ± 0.8
0.001
Chest AIS
2.9 ± 0.7
3.1 ± 0.8
0.001
Abdomen AIS
2.8 ± 1.0
3.0 ± 1.1
0.02
Intubation
415 (48.1)
323 (99.1)
0.001
Exploratory laparotomy
166 (19.3)
98 (30.1)
0.001
Craniotomy/craniectomy
29 (3.4)
11 (3.4)
0.99
ORIF
225 (26.1)
3 (0.9)
0.001
Blood transfusion
506 (58.7)
287 (88.0)
0.001
Blood units transfused
6 (1-56)
8 (1-73)
0.001
MTP activation
197 (22.9)
184 (56.4)
0.001
Complications
ARDS
25 (2.9)
24 (7.4)
0.001
VAP
100 (11.6)
24 (7.4)
0.03
Sepsis
35 (4.1)
22 (6.7)
0.05
ICU LOS
7 (1-112)
3 (1-115)
0.001
Ventilator days
6 (1-97)
2 (1-115)
0.001
Hospital length of stay
14 (1-360)
2 (1-115)
0.001
Crude odds ratio of mortality
Table 4 demonstrates the SBP threshold and OR of mortality in trauma patients. The OR for the SBP threshold of 90 mmHg was 14.7 (95%CI = 11.7-18.4) at the ED and 4.8 (95%CI = 3.5-6.6) at the scene. The univariate analysis shows that a drop in SBP below 90 mmHg was associated with a greater mortality risk.
Table 4 Systolic blood pressure threshold and odds ratio of mortality in trauma patients, odd ratio (95% confidence interval).
SBP threshold (mmHg)
Prehospital
Emergency department
< 60 vs ≥ 60
9.324 (3.374-25.769)
23.303 (11.701-46.408)
< 70 vs ≥ 70
9.063 (4.930-16.662)
23.785 (15.754-35.910)
< 80 vs ≥ 80
6.994 (4.642-10.537)
19.937 (14.936-26.612)
< 90 vs ≥ 90
4.835 (3.540-6.604)
14.736 (11.775-18.443)
< 100 vs ≥ 100
3.341 (2.608-4.281)
9.157 (7.546-11.112)
< 110 vs ≥ 110
2.363 (1.913-2.919)
4.616 (3.852-5.531)
< 120 vs ≥ 120
1.541 (1.270-1.869)
2.568 (2.146-3.073)
< 130 vs ≥ 130
1.079 (0.894-1.303)
1.423 (1.174-1.726)
Multivariable logistic regression analysis (adjusted odds ratio of mortality)
Table 5 shows the multivariable analysis for predictors of mortality among trauma patients (Model-1). Hypotension (aOR = 2.505; 95%CI = 1.798-3.489; P = 0.001) and ARDS (aOR = 5.482; 95%CI = 3.297-9.116; P = 0.001) were the independent predictors of mortality after adjusting for age, gender, ISS, blood transfusion, admission GCS and shock index. Furthermore, in model II (hypotensive trauma patients), only ARDS (aOR = 3.518; 95%CI = 1.385-7.204; P = 0.006) was an independent predictor of mortality.
Table 5 Multivariate regression analysis for the predictors of mortality.
The present study shows that the presence of shock or hypotension episode is an important sign of physiological deterioration that poses a significant risk of morbidity and mortality among young trauma patients. These findings are consistent with earlier studies; however, the patients in our study were younger[17,18]. In addition, ARDS was a significant predictor of mortality in both the overall trauma cohort as well as those who developed early hypotension after trauma. Moreover, the odds of mortality for the SBP threshold < 90 vs ≥ 90 mmHg was 15-fold, exponentially increasing with a further drop in every five mmHg of blood pressure.
The current literature exhibits significant variability in defining hypotension among adult trauma patients, with some reports defining SBP thresholds as low as 79 mmHg and others up to 120 mmHg[7]. Our study defined hypotension as SBP < 90 mmHg in either prehospital or in-hospital settings. This is consistent with earlier studies on adult TBI patients, which have considered SBP < 90 mmHg as the cut-off for hypotension[19,20]. A study by Clarke et al[17] suggested that traumatic shock emerges at an SBP of 110 mmHg, and an SBP of 90 mmHg indicates advanced shock or hypotension in trauma patients. The authors found that SBP cut-off < 110 mmHg had higher sensitivity (82%) and positive predictive value (98%) but lower specificity (56%) and negative predictive value (12%) for mortality.
Similarly, Eastridge et al[21] analyzed records of 870,634 patients from the NTDB and found that SBP ≤ 110 mmHg was more clinically relevant threshold for hypotension and hypoperfusion than the cut-off 90 mmHg. Furthermore, their findings indicated that for every 10 mmHg decrease in SBP below 110 mmHg, there was a corresponding 4.8% increase in mortality. Their findings showed that every drop in 5 mmHg of SBP below 90 mmHg was associated with an incremental mortality risk. Similarly, Spaite et al[7] demonstrated higher odds of mortality associated with a drop in SBP in the prehospital settings. The authors showed that a decline of SBP from 110 to 100 mmHg raised mortality probabilities as much as dropping from 90 to 80 mmHg, and so on throughout the range. Also, a multicenter observational study showed an increase in mortality for blood pressure, decreasing by 10 mmHg from 130 to 50 mmHg and increasing from 150 to 220 mmHg, regardless of age[22].
In the present study, 6.9% of patients had an episode of hypotension either at the scene or upon arrival at the hospital. This is slightly higher than the rate of prehospital hypotension (2.4%) in patients who were found normotensive on ED admission[12]. This difference might be due to the consideration of in-hospital hypotension in our cohort and the dynamic nature of blood pressure changes in trauma patients, with some developing hypotension after hospital admission due to secondary injuries or other clinical factors. In our study, hypotensive patients were slightly younger and more likely to have higher pulse rates and injury severity. However, an earlier cohort study of 1227 trauma patients found that patients with prehospital hypotension were somewhat older, had frequent penetrating injuries, and had greater severity of injury as compared to normotensive patients[6]. The variation in age and type of injury could be explained by differences in the demographic characteristics and prevalent injury mechanisms in the geographic regions. An earlier study revealed that isolated prehospital hypotension, even if a patient had normal blood pressure upon admission, was associated with greater injury severity and worse outcomes[3]. Similarly, in our study, hypotensive patients were severely injured, as indicated by higher ISS, AIS, and lower GCS when compared to normotensive patients. Previously, Shapiro et al[23] demonstrated that prehospital hypotension was significantly associated with the need for chest or abdominal surgery and increased mortality. Seamon et al[8] showed that a single episode of hypotension (SBP < 105 mmHg) often necessitates prompt operational or endovascular treatment as well as admission to a surgical ICU. Our study aligns with these findings, highlighting that hypotensive trauma patient more frequently necessitates exploratory laparotomy, blood transfusions, and MTP activation than normotensive patients.
Notably, in our cohort, the rate of in-hospital complications was significantly higher in hypotensive patients. Of note, ARDS is a fatal complication, impacting approximately 5%-10% of severely injured trauma patients[24-26]. However, in our study, ARDS was present in less than 1% of the trauma population with moderate to severe injuries. In addition, patients with hypotension had a significantly higher proportion of ARDS compared to normotensive patients. Killien et al[26] analyzed 1297190 trauma encounters in ten years, and their results align with these findings, showing that ARDS was observed in 3.1% of trauma cases. The authors suggested an association between ARDS, on-admission hypotension, heart rate, and higher injury severity. In our study, the overall mortality rate was 3.7%, and those with hypotension had a significantly higher rate of mortality. Similar to our findings, a retrospective observational study of 1028 trauma patients reported an overall mortality rate of 3%, with a 2.3-fold increased risk of mortality in the prehospital hypotension group as compared to normotensive patients[6]. In our study, hypotensive patients who died were relatively older, had frequent multiple injuries with greater severity, and higher admission SI as compared to survivors. Our study corroborates with earlier research by Damme et al[3], which demonstrated that hypotensive patients had lower GCS at the scene and ED, higher ISS, prolonged hospital course, and worse outcomes. In the overall cohort of our study, hypotension and ARDS were identified as independent predictors of mortality. However, among trauma patients with hypotension, only ARDS remained an independent predictor of mortality after accounting for relevant confounding factors. An earlier study on trauma patients admitted to the ICU reported a 1.9-fold higher risk of mortality in patients who developed hypotensive during ICU admission than in normotensive patients[27]. The mortality rate in trauma patients requiring laparotomy increases with the severity of the hypotension, and increases considerably if the SBP falls below 70 mmHg[28]. ARDS alone continues to be associated with a higher rate of mortality (up to 60%), which further increases to 50%-80% when coupled with multiple organ failure, despite recent improvements in respiratory critical care[29-31]. Another study based on the data from the NTDB reported that among adult trauma patients who developed post-traumatic ARDS, independent predictors of mortality included early hypotension at hospital admission and advanced age (> 55 years)[32].
The current observational study has certain limitations which are worth mentioning. First, it is a retrospective data analysis from a single center. The presence of chronic conditions such as hypertension and the utilization of anti-hypertensive medications among patients may have impacted the recorded SBP values, potentially complicating the assessment of hypotension related to trauma. It’s important to acknowledge that unaccounted confounding variables in our retrospective analysis could affect our results. Another limitation is the lack of data on the duration of each hypotensive episodes, a factor that could be considered in a prospective, well-designed study. While the exact length of time that an individual patient can survive depends on their specific injuries, studies have demonstrated that reducing the time between injury and lifesaving interventions is critical for optimizing injury survival. Furthermore, the present study findings reflected correlations but did not imply causations. Finally, the results could be gender-biased as 90% of the patients were male, which reflects the pattern of trauma demographics in Qatar[33,34].
CONCLUSION
The current study demonstrates that hypotensive episodes defined by SBP < 90 mmHg following traumatic injury in young patients are associated with higher injury severity, more need for laparotomy and blood transfusion, and unfavorable outcomes. The development of ARDS is an independent predictor of mortality in hypotensive trauma patients. Hence, it is essential to consider a single episode of acute hypotension during triage, as this may prove physiologically detrimental with impaired organ perfusion and the worst outcome in trauma patients. Therefore, patients with a tendency to experience hypotensive episodes should be closely monitored.
ACKNOWLEDGEMENTS
The authors thank all the staff of the trauma registry database at the trauma surgery section, Department of Surgery, at Hamad General Hospital, Doha, Qatar.
Footnotes
Provenance and peer review: Invited article; Externally peer reviewed.
Peer-review model: Single blind
Specialty type: Critical care medicine
Country of origin: Qatar
Peer-review report’s classification
Scientific Quality: Grade B
Novelty: Grade B
Creativity or Innovation: Grade B
Scientific Significance: Grade B
P-Reviewer: Vyshka G S-Editor: Lin C L-Editor: A P-Editor: Zhang XD
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