Trauma persists among the main causes of morbidity, death worldwide. It not only affects people of all ages, but also especially old and middle-aged people. Trauma is a major challenge to humanity and forms five of the top ten leading causes of death worldwide. Among the various forms of trauma, polytrauma stands out as a severe event in which there are multiple injuries to different body regions, with at least one being life-threatening. The severity of polytrauma is mainly measured using the Injury Severity Score (ISS), with a specific value of ISS >16 that is used to define major trauma. In addition, this condition has been described by Trentz as a multiple severe injuries syndrome (ISS ≥17) which causes excessive and systemic inflammatory responses, leading to remote organ dysfunction or failure in the heart, lungs, liver, kidneys, bones, or systemic immune system [1].

Road traffic accidents are responsible for 37% of polytrauma, followed by falls at 30%, and trauma is more prevalent in men and peaks in those aged 16 to 24. The WHO approximates 98 injuries per 100,000 individuals worldwide, with injuries being among the top five leading causes of death. Severe trauma cases (ISS 16–24) account for 12.8%, and extremely severe cases (ISS >24) account for 9.6%. Central nervous system (CNS) trauma is the predominant cause of traumatic deaths, accounting for 21.6%–71.5% of mortality, followed by exsanguination for 12.5%–26.6%. Trauma is responsible for more than 5 million deaths per year and is likely to emerge as the third leading disease burden in the world. Late complications in survivors include sepsis (3.1%–17%) and multiorgan failure (1.6%–9%) as the most frequent causes of morbidity [2-3].

The way in which trauma patients are assessed and the speed by which early intervention is administered are vital to enhancing their chances for survival and lowering the likelihood for complications. There are a number of tools and parameters - like different scoring systems and vital signs - in use which are designed to give an overview of the level and complexity of injury and indicate the need for intensive care. There is a consensus that systolic blood pressure (SBP) underneath 90 mmHg is considered an indicator of shock and calls for utmost resuscitation exertions. However, recently completed studies convey that the shock index might present a more exceptional metric to forecast hemorrhagic shock in comparison to SBP. Besides, the latest research proposes that an SBP cut-off point of 110 mmHg could serve as a better representation of an individual's early physiological reactions [4-5].

The delivery of oxygen is crucial to sustain life at a cellular level. Diseases like occult hemorrhagic or septic shock lead to less oxygen delivery, which stops the cellular metabolism in the body and production of anaerobic products like acids. The acidosis state to some degree reflects perfusion insufficiency owing to hypovolaemic ischaemia. The best available surrogate for assessment of occult hypoperfusion remains to be the base deficit. Age, prothrombin time, injury severity score (ISS), GCS and glucose and lactate levels have been identified in the literature as important predictors of outcome in traumatic shock [6].

Serum lactate is widely recognized as a sensitive marker of hypoxemia and metabolic challenge. In the state of persistent lactic acidosis, after damage, the results are lung capacity endangerment, multiorgan crashing, and heightened vulnerability. Therefore, serum lactate serves to be a useful diagnostic and prognostic biomarker for trauma persons.

Lactate clearance, or decrease in serum lactate concentration over time after resuscitation, has been recognized as an important indicator of clinical outcome in trauma patients. Research has proven that delayed lactate clearance is linked to increased morbidity and mortality. For example, a study conducted by Abramson et al. proved that surviving trauma patients had normalized lactate clearance, while non-surviving patients had abnormally increased lactate clearance. In addition, lactate clearance has also been shown to be a better prognostic indicator than traditional vital signs like blood pressure and heart rate [7].

Although lactate has been well established as a key biomarker, the prognostic role of serum lactate concentration in hemodynamically stable polytrauma patients is still under-researched. Although the Advanced Trauma Life Support (ATLS) protocol warns against relying on SBP in the identification of shock as it is not sensitive to convert hypoperfusion, lactate clearance is more dynamic and more accurate in the prediction of patient prognosis. Normalization of central venous oxygen saturation and lactate clearance are superior to guiding resuscitation and patient outcomes [8].

Serum lactate concentration and lactate clearance are valuable markers of the physiological status and prognosis of polytrauma patients. Because of the limitations of traditional vital signs in the diagnosis of occult shock, inclusion of lactate monitoring in trauma protocols may allow for earlier detection and timely intervention. The current study is designed to evaluate the predictive value of blood lactate concentration and lactate clearance in the prediction of morbidity and mortality in polytrauma patients admitted to the emergency department of Assam Medical College and Hospital, Dibrugarh. By evaluating the variation in lactate concentration with attempts at resuscitation in the first few hours of treatment, the current study is designed to optimize trauma care and improve patient outcomes.

Study Design and Setting

This prospective observational hospital-based study was carried out in the Department of Orthopaedics, Assam Medical College and Hospital, Dibrugarh, for a period of one year from March 2023 to February 2024. The study aimed to assess serum lactate concentration and lactate clearance as prognostic indicators of morbidity and mortality among polytrauma patients admitted to the emergency department.

Study Population

It involved polytrauma patients fulfilling the inclusion criteria who were admitted to the emergency department of Assam Medical College and Hospital during the study period.

Inclusion Criteria

Patients in this study were those over 12 years of age who had polytrauma and an Injury Severity Score (ISS) of more than 16. Moreover, only patients who gave informed consent were included in the study. These inclusion criteria helped to ensure that the study population was made up of severely injured patients who needed intensive monitoring and treatment, thus enabling proper evaluation of serum lactate and lactate clearance as predictors.

Exclusion Criteria

Some patient groups were excluded to reduce confounding variables that may impact serum lactate levels and outcomes. Pregnant females were excluded because of physiological differences in lactate metabolism during pregnancy. Patients with existing coronary artery disease, renal failure, or liver dysfunction were excluded because these diseases would independently affect lactate metabolism and clearance. In addition, malignancy or acute pancreatitis patients were not recruited because these factors might lead to systemic inflammatory reaction and metabolic change. Patients who had a background of immunosuppressive treatment or antiretroviral treatment (ART) were excluded in order to avoid the potential impact of dysregulation in immune function on patient outcomes.

Sample Size Calculation

According to past research, it was found that a time of ≥24 hours taken for lactate normalization was related to a 30% mortality in polytrauma patients. The sample size was calculated at 81 patients with a margin of error of 10% and a 95% confidence level.

Data Collection and Clinical Assessment

When admitted to the emergency department, each patient's vital signs were noted, such as blood pressure, heart rate, respiratory rate, and oxygen saturation. Demographics, such as age, sex, and mode of injury, were noted. Prehospital time, which represents the time between the time of trauma and arrival at the hospital, was also noted. In prehospital care provided to the patient, fluid resuscitation, oxygenation, or immobilization methods were recorded.

Resuscitation was commenced according to the routine Advanced Trauma Life Support (ATLS) protocol. In compound fracture cases, the Mangled Extremity Severity Score was determined to evaluate limb viability. The baseline blood tests, such as hemoglobin (Hb), packed cell volume (PCV), and serum lactate, were taken upon admission. Blood transfusion needs were established according to clinical parameters, Hb levels, and PCV.

After being hemodynamically stabilized, the patients underwent additional diagnostic imaging, which involved X-rays, CT scans, USG, and ECG whenever necessary. Life-saving emergency procedures like pelvic external fixation, thoracocentesis, needle thoracostomy, intercostal drainage, and splinting of fractures were carried out as indicated.

Serum Lactate Measurement

Procedure for Sample Collection

Lactate was assayed from blood samples by drawing them in sodium fluoride (NaF)-coated blood collection tubes to prevent glycolysis. The samples were immediately kept in an ice box and transported to the biochemistry laboratory, where they were centrifuged within 15 minutes of collection to yield plasma for lactate estimation.

Lactate Estimation Method

Lactate was determined in a colorimetric assay at Assam Medical College and Hospital, Dibrugarh, in the Medical Research Unit (MRU). The test was carried out based on lactate enzymatic oxidation to pyruvate by lactate oxidase (LOD). Reaction-formed hydrogen peroxide was further oxidized to a colored compound by peroxidase (POD), and absorbance was quantitated to identify the concentration of lactate. Color intensity was proportional directly to the concentration of lactate in the blood sample.

The level of serum lactate was measured in mg/dL and converted to mmol/L using the formula:

Lactate (mmol/L)=Lactate (mg/dL)×0.111

Based on previous research, the cut-off for abnormal values was the lactate value of 19.8 mg/dL with mean and median values of 18 mg/dL and 21.5 mg/dL, respectively. The value of lactate ≤19.8 mg/dL was utilized as being within normal range.

Lactate Clearance Calculation

Serum lactate levels were obtained at varying time points to assess lactate clearance, a critical indicator of tissue perfusion and metabolic status. Venous blood was collected at the time of admission (0 hours), 6 hours, and 24 hours. Lactate clearance was subsequently determined as follows: [(Lactate Initial - Lactate Delayed) / Lactate Initial] × 100. The three major lactate clearance periods examined were 0 to 6 hours, 0 to 24 hours, and 6 to 24 hours. An elevated lactate clearance percentage reflected improved resuscitation and improved prognosis for the patient, whereas abnormally high lactate levels implied continued tissue hypoxia and increased risk for complications.

Clinical Management and Monitoring

The patients were monitored 24 hours a day for vital signs, oxygen saturation, and other vital parameters throughout the hospital course. Laboratory investigations such as serum electrolytes, blood urea, serum creatinine, blood glucose, and complete blood count (CBC) were done at 24 hours. Oxygen therapy was applied in cases where oxygen saturation was less than 95% and was stopped once normal saturation was restored. Endotracheal intubation and ventilatory assistance was provided to the patients who presented with respiratory distress or arrest and was monitored by the resident anesthetists on duty. Inotropic support was started in those patients with persistent hypotension at the intensivist's suggestion. All the complications like infection, sepsis, and hemodynamic instability were actively treated. Once stabilized, patients were shifted to general wards for rehabilitation and further medical treatment.

Study Endpoints

The patients' outcome was evaluated against several qualitative factors that indicated severity of trauma as well as efficiency of resuscitation. Death within 48 hours of presentation was considered as early mortality and prolonged intensive care unit (ICU) stay was defined by ICU admission lasting greater than two days. The 30-day mortality and the complications of sepsis and multiple organ dysfunction syndrome (MODS) were also noted. The surviving patients were also classified according to patterns of recovery, such as those with late recovery complicated by sequelae or complications and those who recovered early without major complications. The requirement for immediate interventions like emergency operations, embolization, blood transfusion, or intercostal drainage was also recorded as part of the results assessment.

Statistical Analysis

All the data collected, such as serum lactate levels, lactate clearance values, and outcome measures, were statistically assessed for significance in patient prognosis prediction. For continuous variables, mean and standard deviation were computed, whereas categorical variables were presented in proportion. The unpaired Student's t-test was utilized in comparing two means, while the Mann-Whitney test was employed in comparing medians. Categorical data were analyzed using Fisher's exact test. The relationship between serum lactate concentration, lactate clearance, and outcome was examined by linear regression analysis. Multiple logistic regression models were used to determine the predictive ability of lactate clearance after adjusting for other variables like ISS scores and initial lactate concentration. The precision of serum lactate and lactate clearance in the prediction of patient outcomes was also evaluated by determining the area under the receiver operating characteristic (ROC) curve. Model calibration was confirmed with the Hosmer-Lemeshow goodness-of-fit test, and odds ratios with a 95% confidence interval were presented to measure the strength of associations.

Demographics and Baseline Characteristics

The research involved 81 polytrauma patients, with a mean age of 36.28 years. The largest group of patients (44%) was younger than 30 years, and 27% were in the 31–40 years category. Interestingly, the earliest recovery was seen among patients aged 31–40 years (34.1%), while all deaths were in patients older than 50 years. Statistical analysis did not prove the correlation between age and clinical results (p = 0.107) (Table 1, Figure 1).

Table 1: Age Distribution

P-value = 0.107 (Fisher Exact Test)

Men represented 90% of the population studied, indicating the increased prevalence of trauma in men. In spite of this, sex did not prove to be a significant predictor of outcome since no statistical correlation was seen (p = 0.963) (Table 2, Figure 2).

Table 2: Distribution of Outcomes by Gender

Figure 2: Distribution of Outcomes by Gender

Of the mechanisms of injury, road traffic accidents (RTAs) were the most frequent and accounted for 86.4% of patients. Falls (12.3%) and train accidents (1.2%) were less common, and the mechanism of injury did not have a significant influence on patient outcomes (p = 0.771) (Table 3, Figure 3).

Table 3: Mode of Injury vs Outcome

       p-value = 0.771 (Fisher Exact Test)

Clinical Parameters and Their Influence on Outcomes

The Injury Severity Score (ISS) was the most important predictor of patient prognosis. The average ISS was considerably greater in the fatal group (33.0 ± 1.41) than in the early recovered patients (19.78 ± 3.69) (p < 0.001), suggesting that the more severe patients were more likely to die (Table 4, Figure 4).

Table 4:  ISS vs. Outcome

p-value = <0.001 (ANOVA Test, significant at the 5% level)

ISS also correlated positively with serum lactate at admission (r = 0.377, p = 0.001), which further supports the association between the severity of the injury and metabolic distress (Table 5).

Table 5:  ISS vs. Serum Lactate

Systolic blood pressure (SBP) upon admission was critical in determining outcome. Patients with early recovery had a mean SBP of 117.61 ± 11.38 mmHg, whereas those who died from injuries had lower SBP levels (66.0 ± 8.49 mmHg) (p < 0.001) (Table 6, Figure 6).

Table 6: SBP vs Outcome

p-value = <0.001* (ANOVA Test, significant at the 5% level)

There was a significant inverse correlation between SBP and serum lactate concentrations (r = -0.647, p < 0.001), implying that hypotension was accompanied by elevated lactate concentrations and poor prognosis (Table 7).

Table 7: SBP vs Serum Lactate

Serum Lactate Levels, Lactate Clearance, and ICU Stay

Admission serum lactate was also a significant predictor of mortality. Early recovery patients had a mean lactate value of 30.52 ± 3.75 mg/dl, while the non-survivors had much higher values (82.55 ± 3.04 mg/dl) (p < 0.001) (Table 8, Figure 8).

Table 8:  Serum Lactate vs Outcome

      p-value = <0.001 (ANOVA Test, significant at the 5% level)

In addition, failure of lactate clearance in the first 24 hours after admission was significantly related to delayed recovery or late complications (p = 0.024) (Table 9).

Table 9: Lactate Clearance vs Outcome

       p-value = 0.013 (0 hour), 0.797 (6 hours), 0.024 (24 hours)

A longer duration of ICU stay (>24 hours) was associated with a higher risk of complications, i.e., sepsis and AKI. Patients with a longer ICU stay had a very high rate of adverse outcomes and sequelae (p < 0.001) (Table 10 5.4, Figure 5.4).

Table 10:  ICU Stay vs Outcome

        p-value = <0.001 (Fisher Exact Test, significant at the 5% level)

Key Correlations and Clinical Implications

Greater serum lactate concentrations at admission were strongly correlated with longer ICU hospitalization (r = 0.377, p = 0.001) and a higher requirement for blood transfusion (r = 0.271, p = 0.016) (Tables 11 - 12).

Table 11: Serum Lactate vs ICU Stay

Table 12: Serum Lactate vs Blood Transfusion

Case reports also underscored the prognostic value of lactate clearance. For example, patients presenting with lactate concentrations above 80 mg/dl, as in Case 3, had rapid clinical decline and mortality within hours. Conversely, patients with normalization of lactate in the early phase, like Case 1, exhibited significant improvement and rapid recovery.

The research reaffirms that ISS, SBP, and serum lactate concentrations are independent predictors of clinical outcomes in polytrauma patients. Early clearance of lactate and hemodynamic stabilization were significant factors in minimizing mortality and complications. Age and sex, on the other hand, were not independent predictors of outcome. These results highlight the need for prompt resuscitation and ongoing metabolic monitoring in trauma care to enhance survival and recovery.

The results of this research present important clinical and prognostic features of polytrauma patients, with the major emphasis placed on the predictive value of serum lactate concentration, lactate clearance, and hemodynamic data. The study group was mainly represented by young patients, where 44% of the patients were younger than 30 years and 27% were in the 31–40-year age group. This pattern is consistent with existing literature, suggesting that young, active individuals are more frequently involved in high-impact trauma, particularly road traffic accidents. The relatively superior recovery observed in younger patients can be attributed to their greater physiological resilience, better healing potential, and lower burden of comorbidities.

Sex distribution in the study was highly skewed, with 90% of the patients being male. Although this is consistent with the greater prevalence of trauma in men, statistical analysis revealed no significant correlation between sex and outcome. With regard to mechanism of injury, road traffic accidents were the most common cause, representing 86.4% of cases, followed by falls (12.3%) and train accidents (1.2%). While severity of trauma differed within these groups, the mode of injury per se did not have a significant bearing on the ultimate outcome [9].

One of the important observations was the high correlation between the Injury Severity Score (ISS) and clinical outcome. Patients with a higher ISS score showed significantly worse outcomes, and cases of fatalities had a mean ISS of 33.0 ± 1.41, while early recovery cases had a mean ISS of 19.78 ± 3.69. Although ISS was a very good predictor of mortality and complications, it was not always absolute in predicting patient outcomes. A patient with ISS 16, who had complex Grade IIIB distal femur fractures, had an unanticipated protracted recovery following septicemia and wound infection despite early debridement and day one external fixation. This highlights the multifactorial aspect of trauma recovery, where secondary complications, infection control, and tailored treatment approaches are important factors in recovery [10-11].

Systolic blood pressure at admission emerged as another strong predictor of clinical outcomes. Patients with lower SBP at admission had significantly worse prognosis, with a marked difference between survivors and non-survivors. The inverse correlation between SBP and serum lactate levels reinforces the role of hemodynamic stability in trauma recovery. The study findings align with existing research indicating that hypotension, when coupled with elevated lactate levels, signifies a higher risk of mortality and prolonged hospitalization.

Serum lactate concentrations and clearance during the first hours of hospitalization were the key prognostic factors. Admission lactate concentrations significantly correlated with adverse outcome, and the fatal cases had a mean lactate concentration of 82.55 ± 3.04 mg/dl as opposed to 30.52 ± 3.75 mg/dl among early recoveries. Clearance of lactate during the first 24 hours was equally predictive of prognosis. Early recovery patients had a mean lactate clearance of 18.49%, while insufficient clearance was related to late recovery and higher complications. This concurs with the increased body of literature that implies prolonged lactic acidosis is linked to higher dangers of multiple organ dysfunction and mortality [12].

The use of serum lactate as a predictive tool among trauma patients has been extensively established in literature. Earlier research has shown that lactate levels start increasing within 30 minutes of severe trauma, which indicates the extent of metabolic stress and tissue hypoxia. Manikis et al. found major differences in mean lactate levels between survivors and non-survivors of ICU-admitted trauma patients. Likewise, Abramson et al. have reported that the time taken for lactate normalization is a good predictor of mortality in multi-trauma patients. The theory of "second-hit" trauma whereby surgical intervention after the inflammatory stage aggravates results has also found support in retrospect studies showing better recovery in cases of major surgery performed after four days of injury.

The relationship between lactate levels and systemic complications like acute lung injury is also a good indicator of prognosis. Endothelial injury, inhibition of pyruvate dehydrogenase, and associated hypoxia all play a part in the lactate elevation seen in chest injury patients and so are an important marker for heightened morbidity and mortality. Aslar et al. proved that admission serum lactate values and APACHE II scores were predictive of outcome for thoracic trauma. These results are consistent with the current study's finding that patients with chronically elevated lactate levels had poorer outcomes, such as respiratory failure and multiple organ dysfunction [13].

One of the key implications of the study is that lactate clearance is a useful prognostic marker, even in patients with stable vital signs. This indicates that, sometimes, overt trauma scores could fail to diagnose occult hypoperfusion, warranting the presence of metabolic parameters like lactate in initial management protocols. Lactate values correlating with initial values as well as with ISS, making it essential in decision-making within clinical settings, is another argument that comes into focus. Also noted are that prehospital prompt care is quite vital, seeing as delayed resuscitation implies higher initial levels of lactate and worse results [14].

Although lactate clearance has high predictive value, it cannot completely substitute traditional trauma scoring systems. The research noted that early hours lactate levels did not add substantially to trauma scores like MGAP, RTS, or TRISS in hemodynamically stable patients. This shows that although lactate clearance can be helpful in determining the efficacy of resuscitation, it might not be adequate in the detection of occult hypoperfusion in patients with normal blood pressure. Preliminary evidence also indicates that microcirculatory blood flow measurements may offer a more realistic appraisal in such situations [15].

The research results also carry important clinical and economic bearings. Both baseline lactate and lactate clearance are associated with ICU stay length, making both valuable predictors of hospital resource use. Higher lactate values are associated with significant bleeding and the requirement for massive transfusion, providing further justification for use in trauma care. Application of damage control orthopedics, which limits secondary injury among occult hypoperfusion polytrauma patients, is another serious factor in bettering patient outcome.

There are certain limitations. The study is carried out in an adult cohort, and findings might not have a direct transferability to child trauma patients. Furthermore, an observational study allows us to find correlation but certainly does not assure us of causation. Additional interventional research is required to determine if manipulation of lactate clearance with specific therapeutic interventions will enhance trauma outcome. In spite of these caveats, the study offers insights into the prognostic utility of serum lactate and affirms the utility of thorough metabolic monitoring in the trauma patient.

The results of this study substantiate the prognostic value of serum lactate concentration and lactate clearance in the early evaluation, management, and prognostication of polytrauma patients. An elevated admission lactate level is highly correlated with elevated risk of mortality, whereas adequate lactate clearance during the first 24–48 hours predicted improved clinical outcome. Serial lactate measurements offered a better evaluation of current shock and resuscitation effectiveness than an isolated measurement and are an important tool in directing treatment decisions. The combination of lactate clearance with clinical, radiologic, and trauma scoring techniques can be useful in decision-making on the selection of early total care versus damage control orthopedics in long bone and pelvic fractures. In addition, continuously elevated lactate levels after initial resuscitation can be a sign of occult injury, like thoracic trauma, and require additional intervention. Due to its prognostic value, lactate clearance must be routinely integrated into trauma management protocols, and close communication with anesthesiologists must be ensured to maximize resuscitation and enhance patient outcomes in the intensive care unit.

1. Bucholz RW. Rockwood and Green’s fractures in adults. Lippincott Williams & Wilkins; 2006. In.
2. Sikand M, Williams K, White C, Moran CG. The financial cost of treating polytrauma: implications for tertiary referral centres in the United Kingdom. Injury. 2005;36(6):733–7.
3. Keel M, Trentz O. Pathophysiology of polytrauma. Injury. 2005;36(6):691– 709.
4. Gururaj G. Injuries in India: A national perspective. Burden of disease in India. 2005;325.
5. Textbook of Polytrauma Management: A Multidisciplinary Approach | SpringerLink [Internet]. [cited 2024 Aug 3]. Available from: https://link.springer.com/book/10.1007/978-3-030-95906-7
6. Pfeifer R, Tarkin IS, Rocos B, Pape HC. Patterns of mortality and causes of death in polytrauma patients—has anything changed? Injury. 2009;40(9):907– 11.
7. Pape H, Peitzman AB, Schwab C, Giannoudis P. Damage Control Management in the Polytrauma Patient. 2010. 1 p.
8. King RW, Plewa MC, Buderer NMF, Knotts FB. Shock Index as a Marker for Significant Injury in Trauma Patients. Academic Emergency Medicine. 1996;3(11):1041–5.
9. Moomey CB, Melton SM, Croce MA, Fabian TC, Proctor KG. Prognostic value of blood lactate, base deficit, and oxygen-derived variables in an LD50 model of penetrating trauma. Critical Care Medicine. 1999 Jan;27(1):154.
10. Husain FA, Martin MJ, Mullenix PS, Steele SR, Elliott DC. Serum lactate and base deficit as predictors of mortality and morbidity. Am J Surg. 2003 May;185(5):485–91. BIBLIOGRAPHY  46
11. Davis JW, Kaups KL, Parks SN. Base Deficit Is Superior to pH in Evaluating Clearance of Acidosis after Traumatic Shock: The Journal of Trauma: Injury, Infection, and Critical Care. 1998 Jan;44(1):114–8.
12. Vandromme MJ, Griffin RL, Weinberg JA, Rue LW, Kerby JD. Lactate is a better predictor than systolic blood pressure for determining blood requirement and mortality: could prehospital measures improve trauma triage? J Am Coll Surg. 2010 May;210(5):861–7, 867–9.
13. Nguyen HB, Rivers EP, Knoblich BP, Jacobsen G, Muzzin A, Ressler JA, et al. Early lactate clearance is associated with improved outcome in severe sepsis and septic shock. Crit Care Med. 2004 Aug;32(8):1637–42.
14. Claridge JA, Crabtree TD, Pelletier SJ, Butler K, Sawyer RG, Young JS. Persistent occult hypoperfusion is associated with a significant increase in infection rate and mortality in major trauma patients. J Trauma. 2000 Jan;48(1):8–14; discussion 14-15. 16. Naemsp 2005 Annual Meeting. Prehospital Emergency Care. 2005 Jan 1;9(1):102–43.
15. Bentley G. European surgical orthopaedics and traumatology: the Efort textbook. New York: Springer; 2014.