Treatment of liver injuries at level I and level II centers in a multi-institutional metropolitan trauma system. The Midwest Trauma Society Liver Trauma Study Group

Evaluating associations between level of trauma care and outcomes of patients with specific severe injuries: A systematic review and meta-analysis

BACKGROUND

Trauma networks have multiple designated levels of trauma care. This classification parallels concentration of major trauma care, creating innovations and improving outcome measures.

OBJECTIVES

The objective of this study is to assess associations of level of trauma care with patient outcomes for populations with specific severe injuries.

METHODS

A systematic literature search was conducted using six electronic databases up to April 19, 2022 (PROSPERO CRD42022327576). Studies comparing fatal, nonfatal clinical, or functional outcomes across different levels of trauma care for trauma populations with specific severe injuries or injured body region (Abbreviated Injury Scale score ≥3) were included. Two independent reviewers included studies, extracted data, and assessed quality. Unadjusted and adjusted pooled effect sizes were calculated with random-effects meta-analysis comparing Level I and Level II trauma centers.

RESULTS

Thirty-five studies (1,100,888 patients) were included, of which 25 studies (n = 443,095) used for meta-analysis, suggesting a survival benefit for the severely injured admitted to a Level I trauma center compared with a Level II trauma center (adjusted odds ratio [OR], 1.15; 95% confidence interval [CI], 1.06-1.25). Adjusted subgroup analysis on in-hospital mortality was done for patients with traumatic brain injuries (OR, 1.23; 95% CI, 1.01-1.50) and hemodynamically unstable patients (OR, 1.09; 95% CI, 0.98-1.22). Hospital and intensive care unit length of stay resulted in an unadjusted mean difference of -1.63 (95% CI, -2.89 to -0.36) and -0.21 (95% CI, -1.04 to 0.61), respectively, discharged home resulted in an unadjusted OR of 0.92 (95% CI, 0.78-1.09).

CONCLUSION

Severely injured patients admitted to a Level I trauma center have a survival benefit. Nonfatal outcomes were indicative for a longer stay, more intensive care, and more frequently posthospital recovery trajectories after being admitted to top levels of trauma care. Trauma networks with designated levels of trauma care are beneficial to the multidisciplinary character of trauma care.

LEVEL OF EVIDENCE

Systematic review and meta-analysis; Level III.

Variability in management of blunt liver trauma and contribution of level of American College of Surgeons Committee on Trauma verification status on mortality

BACKGROUND

Patients who sustain blunt liver trauma and are treated at an American College of Surgeons Committee on Trauma-verified Level I trauma center have an overall lower risk of mortality compared with patients admitted to a level II trauma center. However, elements contributing to these differences are unknown. We hypothesize that practice variation exists between trauma centers in management of blunt liver injury. Our objective is to identify practice variations and their effect on clinical outcomes.

METHODS

Data from a statewide collaborative quality initiative for trauma were used. The data set contains information from 29 American College of Surgeons Committee on Trauma verified Levels I and II trauma centers from 2011 to 2016. Propensity score matching was used to create cohorts of patients treated at Levels I or II trauma centers. The 1:1 matched cohorts were used to compare in-hospital mortality, management strategy, complications, intensive care unit (ICU) and hospital length of stay, and failure to rescue.

RESULTS

Four hundred fifty-four patients with grade 3 or higher blunt liver injury were included. Patients treated at level II trauma centers had higher in-hospital mortality than those treated at Level I trauma centers (15.4% vs 8.8%, p = 0.03). Level II trauma centers used angiography less compared with Level I centers (p = 0.007) and admitted significantly fewer patients to the ICU (p = 0.002). The ICU status was associated with reduced mortality (7.2% vs 23.9%, p < 0.001). Despite a lower rate of overall complications, Level II trauma centers were more likely to fail in rescuing their patients (p = 0.045).

CONCLUSION

Admission with a high-grade liver injury to a Level II trauma center is associated with increased in-hospital mortality. Level II trauma centers were less likely to use angiography or admit high-grade liver injuries to the ICU. This variation in practice may lead to the inability to rescue critically ill patients. Future research should investigate contributors to underutilization of resources for patients with high-grade liver injuries.

LEVEL OF EVIDENCE

Care management, level IV.

The "mortality ascent": Hourly risk of death for hemodynamically unstable trauma patients at Level II versus Level I trauma centers

BACKGROUND

Severely injured trauma patients have higher in-hospital mortality at Level II versus Level I trauma centers (TCs). To better understand these differences, we sought to determine if there were any periods during which hemodynamically unstable trauma patients are at higher risk of death at Level II versus Level I TCs within the first 24 hours postadmission.

STUDY DESIGN

Trauma patients aged 18 years to 64 years, with Injury Severity Score of 15 or greater, systolic blood pressure less than 90 mm Hg at admission, and treated at Level II or Level I TCs, were identified using the 2007 to 2012 National Trauma Data Bank. Burn patients, transfers, and patients dead on arrival were excluded. Log-binomial regression models, adjusted for patient- and hospital-level confounders, were used to compare mortality at Level II versus Level I TCs over the first 24 hours postadmission.

RESULTS

Of 13,846 hemodynamically unstable patients, 4,212 (30.4%) were treated at 149 Level II TCs, and 9,634 (69.6%) at 116 Level I TCs. Within the first 24 hours, 3,059 (22.1%) patients died. In risk-adjusted models, mortality risk was significantly elevated at Level II versus Level I TCs during the 24 hours postadmission (relative risk, 1.08; 95% confidence interval, 1.01-1.16). Hourly mortality risk was significantly different between Level II and Level I TCs during 4 hours to 7 hours postadmission, with a maximal difference at 7 hours (relative risk, 1.70; 95% confidence interval, 1.23-2.36) and comparable mortality risk beyond 7 hours postadmission.

CONCLUSION

The 4-hour to 7-hour time window postadmission is critical for hemodynamically unstable trauma patients. Variations in available treatment modalities may account for higher relative mortality at Level II TCs during this time. Further investigation to elucidate specific risk factors for mortality during this period may lead to reductions in in-hospital mortality among hemodynamically unstable trauma patients.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Liver trauma: WSES position paper

The liver is the most injured organ in abdominal trauma. Road traffic crashes and antisocial, violent behavior account for the majority of liver injuries. The present position paper represents the position of the World Society of Emergency Surgery (WSES) about the management of liver injuries.

Relationship of trauma centre characteristics and patient outcomes: a systematic review

AIMS AND OBJECTIVES

To systematically review the relationship of trauma centre characteristics and trauma patient outcomes.

BACKGROUND

Numerous studies have documented the impact of trauma centre level, trauma centre verification, volume per centre and per surgeon or resource availability on outcomes among trauma patients. However, there continues to be debated about whether trauma care is comparable by these trauma centre characteristics.

DESIGN

Systematic review.

METHODS

Eligible studies were identified via electronic database searches, footnote chasing and contact with clinical experts. Quality of selected studies was assessed in terms of internal and external validity using 14 questions. Two reviewers independently examined titles, abstracts and whether each met the predefined criteria.

RESULTS

A total of 50 studies which met criteria were selected. Ten of 17 articles showed that level I trauma centres had better patient outcomes than level II centres. The achievement of trauma centre verification by American College of Surgeons or State was beneficial to decreasing mortality and length of stay in 9 of 11 studies. High trauma admission volume was beneficial in 8 of 16 studies. The volume per trauma surgeon did not contribute to better patient outcomes in 4 of 5 studies. The availability of in-house trauma surgeon was beneficial to lower mortality and shorter length of stay in only 2 of 9 studies.

CONCLUSION

This review supports that achieving the trauma centre verification by American College of Surgeons or State is definitely beneficial to patient outcomes. However, the benefit of level I centres compared with level II centres, and volume of annual trauma patients to outcomes is still debating. Further prospective study examining this relationship is required.

RELEVANCE TO CLINICAL PRACTICE

Understanding which characteristics of trauma centre provides the best prospect for improved outcomes depending on patient need and resource availability would allow further appreciation of the processes that foster such enhancement.

Nonoperative management of blunt hepatic injury: an Eastern Association for the Surgery of Trauma practice management guideline

BACKGROUND

During the last century, the management of blunt force trauma to the liver has changed from observation and expectant management in the early part of the 1900s to mainly operative intervention, to the current practice of selective operative and nonoperative management. These issues were first addressed by the Eastern Association for the Surgery of Trauma in the Practice Management Guidelines for Nonoperative Management of Blunt Injury to the Liver and Spleen published online in 2003. Since that time, a large volume of literature on these topics has been published requiring a reevaluation of the previous Eastern Association for the Surgery of Trauma guideline.

METHODS

The National Library of Medicine and the National Institutes of Health MEDLINE database were searched using PubMed (http://www.pubmed.gov). The search was designed to identify English-language citations published after 1996 (the last year included in the previous guideline) using the keywords liver injury and blunt abdominal trauma.

RESULTS

One hundred seventy-six articles were reviewed, of which 94 were used to create the current practice management guideline for the selective nonoperative management of blunt hepatic injury.

CONCLUSION

Most original hepatic guidelines remained valid and were incorporated into the greatly expanded current guidelines as appropriate. Nonoperative management of blunt hepatic injuries currently is the treatment modality of choice in hemodynamically stable patients, irrespective of the grade of injury or patient age. Nonoperative management of blunt hepatic injuries should only be considered in an environment that provides capabilities for monitoring, serial clinical evaluations, and an operating room available for urgent laparotomy. Patients presenting with hemodynamic instability and peritonitis still warrant emergent operative intervention. Intravenous contrast enhanced computed tomographic scan is the diagnostic modality of choice for evaluating blunt hepatic injuries. Repeated imaging should be guided by a patient's clinical status. Adjunctive therapies like angiography, percutaneous drainage, endoscopy/endoscopic retrograde cholangiopancreatography and laparoscopy remain important adjuncts to nonoperative management of hepatic injuries. Despite the explosion of literature on this topic, many questions regarding nonoperative management of blunt hepatic injuries remain without conclusive answers in the literature.

Major hepatic trauma: warm ischemic tolerance of the liver after hemorrhagic shock

BACKGROUND

The management of severe hepatic trauma frequently involves exposing the liver to varying periods of warm ischemia. The ischemic tolerance of the liver, in the setting of hemorrhagic shock (HS) and trauma, is presently unknown. We tested the hypothesis that warm ischemic tolerance of the porcine liver will be decreased following resuscitation from HS.

MATERIALS AND METHODS

Twenty-three Yorkshire pigs were divided into three groups: 1) hepatic ischemia alone (HI, n = 9); 2) hemorrhagic shock alone (HS, n = 3); and 3) hemorrhagic shock plus hepatic ischemia combined (HSHI, n = 11). Following reperfusion, a liver biopsy was obtained and serial blood chemistries were sampled.

RESULTS

Post-operative day 7 mortality was increased in the HSHI group (7/11) compared to the HI (0/9) group, P = 0.038. Notably, deaths did not result from acute liver failure, but rather from intra-operative hemodynamic collapse shortly following hepatic reperfusion. In addition, the HSHI group experienced significantly elevated lactic acid, serum creatinine and liver enzyme levels. Analysis of the liver biopsy samples is consistent with a more severe liver injury in the HSHI group.

CONCLUSIONS

The warm ischemic tolerance of the liver following resuscitation from HS is significantly decreased in this porcine model compared to HS or HI alone. Mortality was associated with acute intra-operative hemodynamic collapse occurring shortly after hepatic reperfusion.

Relationship Between American College of Surgeons Trauma Center Designation and Mortality in Patients with Severe Trauma (Injury Severity Score > 15)

BACKGROUND

We studied the association of the American College of Surgeons (ACS) trauma center designation and mortality in adult patients with severe trauma (Injury Severity Score > 15). ACS designation of trauma centers into different levels requires substantial financial and human resources commitments. There is very little work published on the association of ACS trauma center designation and outcomes in severe trauma.

STUDY DESIGN

National Trauma Data Bank study including all adult trauma admissions (older than 14 years of age) with Injury Severity Score (ISS) > 15. The relationship between ACS level of trauma designation and survival outcomes was evaluated after adjusting for age, mechanism of injury, ISS, hypotension on admission, severe liver trauma, aortic, vena cava, iliac vascular, and penetrating cardiac injuries.

RESULTS

A total of 130,154 patients from 256 trauma centers met the inclusion criteria. Adjusted mortality in ACS-designated Level II centers and undesignated centers was notably higher than in Level I centers (adjusted odds ratio, 1.14; 95% CI, 1.09-120; p < 0.0001 and adjusted odds ratio, 1.09; CI, 1.05-1.13; p < 0.0001, respectively).

CONCLUSIONS

Severely injured patients with ISS > 15 treated in ACS Level I trauma centers have considerably better survival outcomes than those treated in ACS Level II centers.

The effect of trauma center designation and trauma volume on outcome in specific severe injuries

OBJECTIVE

The objective of this study was to investigate the effect of American College of Surgeons (ACS) trauma center designation and trauma volume on outcome in patients with specific severe injuries.

BACKGROUND

Trauma centers are designated by the ACS into different levels on the basis of resources, trauma volume, and educational and research commitment. The criteria for trauma center designation are arbitrary and have never been validated.

METHODS

The National Trauma Data Bank study, which included patients >14 years of age and had injury severity score (ISS) >15, were alive on admission and had at least one of the following severe injuries: aortic, vena cava, iliac vessels, cardiac, grade IV/V liver injuries, quadriplegia, or complex pelvic fractures. Outcomes (mortality, intensive care unit stay, and severe disability at discharge) were compared among level I and II trauma centers and between centers within the same level designation but different volumes of severe trauma (<240 vs > or =240 trauma admissions with ISS >15 per year). The outcomes were adjusted for age (<65 > or =65), gender, mechanism of injury, hypotension on admission, and ISS (< or =25 and >25).

RESULTS

A total of 12,254 patients met the inclusion criteria. Overall, level I centers had significantly lower mortality (25.3% vs 29.3%; adjusted odds ratio [OR], 0.81; 95% confidence interval [CI], 0.71-0.94; P = 0.004) and significantly lower severe disability at discharge (20.3% vs 33.8%, adjusted OR, 0.55; 95% CI, 0.44-0.69; P < 0.001) than level II centers. Subgroup analysis showed that cardiovascular injuries (N = 2004) and grades IV-V liver injuries (N = 1415) had a significantly better survival in level I than level II trauma centers (adjusted P = 0.017 and 0.023, respectively). Overall, there was a significantly better functional outcome in level I centers (adjusted P < 0.001). Subgroup analysis showed level I centers had significantly better functional outcomes in complex pelvic fractures (P < 0.001) and a trend toward better outcomes in the rest of the subgroups. The volume of trauma admissions with ISS >15 (<240 vs > or =240 cases per year) had no effect on outcome in either level I or II centers.

CONCLUSIONS

Level I trauma centers have better outcomes than lower-level centers in patients with specific injuries associated with high mortality and poor functional outcomes. The volume of major trauma admissions does not influence outcome in either level I or II centers. These findings may have significant implications in the planning of trauma systems and the billing of services according to level of accreditation.

Mortality benefit of transfer to level I versus level II trauma centers for head-injured patients

OBJECTIVE

To determine whether head-injured patients transferred to level I trauma centers have reduced mortality relative to transfers to level II trauma centers.

DATA SOURCE/STUDY SETTING

Retrospective cohort study of 542 patients with head injury who initially presented to 1 of 31 rural trauma centers in Oregon and Washington, and were transferred from the emergency department to 1 of 15 level I or level II trauma centers, between 1991 and 1994.

STUDY DESIGN

A bivariate probit, instrumental variables model was used to estimate the effect of transfer to level I versus level II trauma centers on 30-day postdischarge mortality. Independent variables included age, gender, Injury Severity Scale (ISS), other indicators of injury severity, and a dichotomous variable indicating transfer to a level I trauma center. The differential distance between the nearest level I and level II trauma centers was used as an instrument.

PRINCIPAL FINDINGS

Patients transferred to level I trauma centers differ in unmeasured ways from patients transferred to level II trauma centers, biasing estimates based on standard statistical methods. Transfer to a level I trauma center reduced absolute mortality risk by 10.1% (95% confidence interval 0.3%, 22.2%) compared with transfer to level II trauma centers.

CONCLUSIONS

Patients with severe head injuries transferred from rural trauma centers to level I centers are likely to have improved survival relative to transfer to level II centers.

Management of liver trauma with implications for the rural surgeon

BACKGROUND

The majority of patients with liver trauma can be managed conservatively. However, the unstable patient requires emergency laparotomy to control bleeding. Controversy exists regarding the primary surgical management of these injuries. This is of particular relevance for the isolated rural general surgeon.

METHODS

The literature was reviewed by searching MEDLINE databases from 1966 to the present time. The majority of the evidence presented is level 3, with interpretations and recommendations based on the experience of the senior authors.

RESULTS

In the majority of patients, conservative management remains the mainstay of treatment. However, haemodynamic -instability requires urgent laparotomy. Perihepatic packing should be used to arrest bleeding. Primary anatomical resection is rarely indicated, especially in non-specialist centres.

CONCLUSION

In the remote rural setting, severe liver trauma remains a daunting condition for the general surgeon to manage. Primary surgical treatment should be perihepatic packing, stabilization and urgent transfer; there is no place for primary anatomical resection outside specialist units.

A multidisciplinary approach in the management of hepatic injuries

We reviewed 87 patients with hepatic injuries who were admitted to King Chulalongkorn Memorial Hospital, Bangkok, Thailand, from January 1995 to December 1999; 76% of them had sustained blunt trauma and 24% penetrating trauma. Their injury severity scores (ISS) ranged from 4 to 57 (mean 20.94+/-12.8); 50% of them were in shock on arrival; 8.1, 28.7, 25.3, 19.5, and 18.4% suffered from hepatic injuries graded I, II, III, IV, and V, respectively. Seventeen patients (19.5%) were successfully managed non-operatively; three of them underwent hepatic angiography, which in two revealed leakage of contrast medium from the right hepatic artery; both were successfully treated by embolization. One patient had bile leakage and collection, which was successfully treated by ultrasound-guided percutaneous drainage. Seventy patients (80.5%) underwent exploratory laparotomy; nine of them died in the operating room. Of the remaining 61 who left the operating room alive, 21 had perihepatic packing, which was frequently used in those with injuries to segments V, VI, VII, and VIII (Couinaud's nomenclature). Eight patients who had packing and one who had not died in the postoperative period. Two patients who had packing underwent subsequent hepatic angiography with embolization before successful pack removal. The overall mortality was 20.7%. The mortality in complex hepatic injuries (grades IV and V) was 13 out of 33 (39.4%). We believe that non-operative management should be considered in haemodynamically stable patients. Angiography with embolization is invaluable in improving outcome in both non-operative and operative patients. Perihepatic packing is life-saving in complex hepatic injuries that cannot be effectively treated by simple surgical procedures. Finally, ultrasound- or CT-guided percutaneous drainage of bile leakage or collections spared a number of patients from open and complicated surgery.

A statewide analysis of level I and II trauma centers for patients with major injuries

BACKGROUND

This study examines statewide outcomes and resource use in Level I and II trauma centers for patients with major injuries.

METHODS

This study analyzed trauma registry data on patients admitted to North Carolina Level I and II trauma centers from January 1995 to December 1996 with one of four major injuries: thoracic aortic disruption, liver injury, pelvic fracture, or pulmonary contusion.

RESULTS

There were 59 thoracic aortic disruptions, 109 liver injuries, 153 pelvic fractures, and 962 pulmonary contusions identified among 26,030 admissions. Case fatality was not significantly different (Level I, 16.8%; Level II, 14.9%). Hospital charges were significantly higher in Level I centers (Level I, $47,366; Level II, $35,490), but this difference was confined to transferred patients. Controlling for Revised Trauma Score, Injury Severity Score, age, gender, and race, multivariable regression confirmed findings regarding hospital charges, and multiple logistic regression confirmed findings regarding case fatality.

CONCLUSION

Case fatality was similar in Level I and Level II trauma centers in North Carolina, and hospital charges were comparable in patients with comparable injuries not requiring transfer. This suggests that patients with major injuries may be optimally cared for in both Level I and Level II trauma centers.

Significance of minimal or no intraperitoneal fluid visible on CT scan associated with blunt liver and splenic injuries: a multicenter analysis

BACKGROUND

The use of ultrasound (U/S) for the evaluation of patients with blunt abdominal trauma is gaining increasing acceptance. Patients who would have undergone computed tomographic (CT) scan may now be evaluated solely with U/S. Solid organ injuries with minimal or no free fluid may be missed by surgeon sonographers.

OBJECTIVE

The purpose of this study was to describe the incidence and clinical importance of liver and splenic injuries with minimal or no free intraperitoneal fluid visible on CT scan. We hypothesized that these solid organ injuries occur infrequently and are of minor clinical significance.

METHODS

Patient records and CT scans were reviewed for the presence of and outcome associated with blunt liver and splenic injuries with minimal (<250 mL) or no free fluid detected by an attending radiologist. Data were collected from six major trauma centers during a 4-year period before the introduction of U/S and included demographics, grade of injury (American Association for the Surgery of Trauma scale), need for operative intervention, and outcome.

RESULTS

A total of 938 patients with liver and splenic injuries were identified. In this group, 11% of liver injuries and 12% of splenic injuries had no free fluid visible on CT scan and could be missed by diagnostic peritoneal lavage or U/S. Of the 938 patients, 267 (28%) met the inclusion criteria; 161 had injury to the spleen and 125 had injury to the liver. In the 267 patients studied, 97% of the injuries were managed nonoperatively. However, 8 patients (3%) required operative intervention for bleeding. Compared with the liver, the spleen was significantly more likely to bleed (p = 0.01), but the grade of splenic injury was not related to the risk for hemorrhage (p = 0.051).

CONCLUSION

Data from this study suggest that injuries to the liver or spleen with minimal or no intraperitoneal fluid visible on CT scan occur more frequently than predicted but usually are of minimal clinical significance. However, patients with splenic injuries may be missed by abdominal U/S. We found a 5% associated risk of bleeding. Therefore, abdominal U/S should not be used as the sole diagnostic modality in all stable patients at risk for blunt abdominal injury.

Management of liver trauma

BACKGROUND AND METHODS

Management of blunt or penetrating injuries to the liver remains a significant challenge. This review discusses the mechanisms of liver injury, grading system for severity, available diagnostic modalities and current management options. It is based on a Medline literature search and the authors' clinical experience.

RESULTS

Unstable patients require immediate laparotomy, but selected patients who are haemo- dynamically stable may be managed without operation. The preferred operative techniques include resectional debridement, hepatotomy with direct suture ligation and perihepatic packing; anatomical resection, hepatic artery ligation and various bypass techniques have a limited, more defined role for selected injuries. Major complications include haemorrhage, sepsis and bile leak.

CONCLUSION

Enhanced resuscitation, anaesthesia and intensive care have contributed to a significant reduction in mortality rates from liver trauma. Optimum results are obtained with a specialist team that includes an experienced liver surgeon, anaesthetist, endoscopist and interventional hepatobiliary radiologist with expertise in managing postoperative complications.