Abdominal vascular trauma in 760 severely injured patients

Purpose

The relevance of abdominal vascular injuries in polytraumatic patients within a large collective has not yet been thoroughly analyzed. This study aimed at assessing the prevalence of traumatic injuries in relation to outcome and currently established treatment options.

Methods

51,425 patients from the Trauma Registry of the German Society of Trauma Surgery (TR DGU) (1993–2009) were analyzed retrospectively. All patients who had an Injury Severity Score (ISS) of ≥16, were directly admitted to a trauma center and subsequently received treatment for at least three days, were ≥16 years old, and had an abdominal injury (AIS_abdomen ≥2) were included. Patients with abdominal trauma (AIS_abdomen ≥2) were compared with patients with additional vascular trauma (AIS_vascular 2–5).

Results

10,530 (20.5 %) of the 51,425 patients had documented abdominal injury. 760 (7.2 %) of the patients with abdominal injury additionally showed abdominal vascular injury (AIS_abdomen ≥2, AIS_vascular 2–5) and were analyzed based on the classification of the American Association for the Surgery of Trauma (AAST) organ severity score (AAST vascular injury grade: II, 2.4 %; III, 2.7 %; IV, 1.8 %; V, 0.2 %. Patients with high-grade abdominal vascular injury (grades IV and V) showed a significant increase in mortality (IV, 44.6 %; V, 60 %) and consequently a decrease in the need for surgical intervention (IV, 67.4 %; V, 64 %).

Conclusions

The results presented here show the prevalence and outcome of abdominal vascular injuries in a large collective within the TR DGU for the first time. Based on the current literature and these findings, a treatment algorithm has been developed.     

Oxygen consumption with mechanical ventilation in a field anesthesia machine

Field anesthesia machines (FAM) with gas-powered ventilators have been developed for remote locations that may not have a central supply of oxygen. These ventilators may rapidly deplete oxygen cylinders, especially in patients with decreased pulmonary compliance. Our goal in this study was to determine oxygen consumption rates with a contemporary FAM in models of high (HC) and low (LC) pulmonary compliance. Oxygen consumption rates were tested using D cylinders (initial pressure 1700 psig) and the Narkomed M FAM, which uses an air injector to decrease compressed gas consumption by entraining room air as part of the drive gas. Three different tidal volumes (Vt) were tested (500, 750, and 1000 mL) with HC and LC lung models, and the fresh gas flow rate was 1 L/min. Respiratory rate was constant at 10 breaths/min. Oxygen consumption varied directly with Vt and inversely with compliance, increasing from 4.8 +/- 0.07 L/min with the HC-500 mL Vt model to 6.2 +/- 0.05 L/min with the LC-1000 mL Vt model. D cylinder duration ranged from 56.8 +/- 0.4 to 73.6 +/- 1.0 minutes. Assuming oxygen fresh gas flow of 1 L/min, calculating tank duration with the fastest consumption rate underestimated the tank duration for more compliant and smaller Vt models but provided a greater margin of patient safety.     

Intestinal necroses in severely injured patients without abdominal trauma

Bowel necrosis in the critical trauma patient without abdominal involvement or preexisting vascular disease is a known but rare complication. During 1977-1986 we observed 31 cases in 2530 patients. Symptoms were unspecific, and since most of the patients were artificially ventilated, pain and tenderness were of little diagnostic value. Twenty-three patients presented with paralytic ileus, fifteen with diarrhea, and four with melena. In eleven patients diagnosis was made clinically, and in twenty patients at autopsy. Twenty-three patients died from septic shock, six from cerebral complications, and one from myocardial infarction. Risk factors for bowel necrosis were fluid restriction, hypotension, hypoxemia, venous congestion, vasoconstrictive drugs, paralytic ileus, and constipation.     

Impact of a trauma system on outcome of severely injured patients

We examined the impact of a trauma system on the survival of patients with a Trauma Score of 8 or less. We compared the observed survival with that predicted using a method that calculates the probability of survival (Ps) based on age, physiologic score, and anatomic severity of injury. Of 3394 patients triaged to trauma centers in a 12-month period, 283 (8.3%) had a Trauma Score of 8 or less. Sufficient data were available in 189 patients with blunt trauma to make the survival comparison. The Ps was 18%; the observed survival was 29%. Of 60 patients with penetrating trauma and complete data, the Ps was 8%; the observed survival was 20%. We attribute the improved survival to the integration of prehospital and hospital care and expeditious surgery.     

Radiation exposure from diagnostic imaging in severely injured trauma patients

BACKGROUND: Trauma patients often require multiple imaging tests, including computed tomography (CT) scans. CT scanning, however, is associated with high-radiation doses. The purpose of this study was to measure the radiation doses trauma patients receive from diagnostic imaging. METHODS: A prospective cohort study was conducted from June 1, 2004 to March 31, 2005 at a Level I trauma center in Toronto, Canada. All trauma patients who arrived directly from the scene of injury and who survived to discharge were included. Three dosimeters were placed on each patient (neck, chest, and groin) before radiologic examination. Dosimeters were removed before discharge. Surface doses in millisieverts (mSv) at the neck, chest, and groin were measured. Total effective dose, thyroid, breast, and red bone marrow organ doses were then calculated. RESULTS: Trauma patients received a mean effective dose of 22.7 mSv. The standard "linear no threshold" (LNT) model used to extrapolate from effects observed at higher dose levels suggests that this would result in approximately 190 additional cancer deaths in a population of 100,000 individuals so exposed. In addition, the thyroid received a mean dose of 58.5 mSv. Therefore, 4.4 additional fatal thyroid cancers would be expected per 100,000 persons. In all, 22% of all patients had a thyroid dose of over 100 mSv (mean, 156.3 mSv), meaning 11.7 additional fatal thyroid cancers per 100,000 persons would result in this subgroup. CONCLUSION: Trauma patients are exposed to significant radiation doses from diagnostic imaging, resulting in a small but measurable excess cancer risk. This small individual risk may become a greater public health issue as more CT examinations are performed. Unnecessary CT scans should be avoided.     

Pulmonary mechanics in patients with prolonged mechanical ventilation requiring tracheostomy

This study was performed to assess the changes in pulmonary mechanics before and after tracheostomy in patients with prolonged mechanical ventilation and to detect pre-tracheostomy physiologic factors that predict the outcome of weaning from mechanical ventilation. Pulmonary mechanics were recorded before and after tracheostomy in 20 patients. Work of breathing, mean airway resistance and pressure/time product showed no significant differences after tracheostomy. Peak inspiratory pressure was significantly reduced (pre 33.4 +/- 11.8 vs post 28.6 +/- 9.2 mmHg). There was no difference in age or duration of mechanical ventilation between two different groups according to the outcome (weaned and not-weaned). Pre-tracheostomy intrinsic positive end expiratory pressure (PEEPi) was significantly lower in the weaned group (1.1 +/- 1.6 vs 2.7 +/- 1.4 mmHg). A significant difference was also found in pre-tracheostomy compliance (Cstatic) (47.3 +/- 36.9 vs 28.8 +/- 16.5 ml/cmH2O). We concluded that tracheostomy changed pulmonary mechanics very little except for a fall in peak inspiratory pressure. Patients who had better underlying lung mechanics (higher Cstatic and lower PEEPi) had better chances of weaning from mechanical ventilation after tracheostomy.     

A systematic review and meta-analysis comparing outcome of severely injured patients treated in trauma centers following the establishment of trauma systems

BACKGROUND: The establishment of trauma systems was anticipated to improve overall survival for the severely injured patient. We systematically reviewed the published literature to assess if outcome from severe traumatic injury is improved for patients following the establishment of a trauma system. METHODS: A systematic literature review of all population-based studies that evaluated trauma system performance was conducted. A qualitative analysis of each study's design and methodology and a meta-analysis was performed to evaluate the evidence to date of trauma system effectiveness. RESULTS: A search of the literature yielded 14 published articles. Trauma systems demonstrated improved odds of survival in 8 of the 14 reports. The overall quality-weighted odds ratio was 0.85 lower mortality following trauma system implementation. CONCLUSIONS: The results of the meta-analysis showed a 15% reduction in mortality in favor of the presence of a trauma system. Evaluation of trauma system effectiveness must remain an uncompromising commitment to optimal outcome for the injured patient.     

Incidence of asymptomatic pulmonary embolism in moderately to severely injured trauma patients

BACKGROUND: Chest computed tomographic (CT) scanning is used frequently to evaluate symptomatic patients for pulmonary embolus (PE). The incidence of PE diagnosed by helical CT scanning in asymptomatic patients is unknown. METHODS: Asymptomatic trauma patients with an Injury Severity Score > or = 9 were studied with contrast-enhanced helical CT images of the chest, pelvis, and lower extremities. Clot burden was assessed using an anatomic scoring system. Patients not receiving anticoagulation were followed. RESULTS: Twenty-two of 90 patients had a PE. Four had major clot burden, including one patient with a saddle embolus. Risk factors for asymptomatic PE include age (odds ratio [OR], 1.04), head injury (OR, 6.78), chest injury (OR, 4.51), lower extremity injury (OR, 5.03), and transfusion (OR, 3.42). Thirty percent of patients receiving pharmacologic prophylaxis had a PE. CONCLUSION: Asymptomatic PE occur in 24% of moderately to severely injured patients. Age, head, chest, and lower extremity injury are associated with an increased risk. Standard thromboembolic prophylaxis is not reliably protective.     

A trauma algorithm--a decision tool in first aid for severely injured patients

Treatment for severe multiple injuries has quite often been impeded by erroneous diagnostic assessment by inadequately experienced physicians in hectic situations. A trauma algorithm flow chart has been devised for due consideration of all important steps in decision-finding. The therapeutic process has thus been improved, as demonstrated by a prospective study.     

Direct transport versus inter hospital transfer of severely injured trauma patients

IntroductionSeveral studies have suggested that severely injured patients should be transported directly to a trauma centre bypassing the nearest hospital. However, the evidence remains inconclusive. The purpose of this study was to examine the benefits in terms of mortality of direct transport to a trauma centre versus primary treatment in a level II or III centre followed by inter hospital transfer to a trauma centre for severely injured patients without Traumatic Brain Injury (TBI).Patients and methodsWe used the regional trauma registry and included all patients with an Injury Severity Score (ISS) >15 and an Abbreviated Injury Score <4 for head injury. We adjusted for survival bias by including “potential transfers”: patients who died at the nearest hospitals before transportation to a trauma centre.ResultsA total of 439 patients was included. The majority of patients (349/439, 79%) was transported directly to the level I trauma centre (direct group). The transferred group was formed by the remaining 90 patients, of whom 81 were transferred to the level I trauma centre after initial stabilisation elsewhere and 9 patients died in the emergency room before transfer to a level 1 trauma centre could occur. There were no significant differences in baseline and injury characteristics between the groups. Overall, 60 patients died in-hospital including 41 of the 349 patients (12%) in the direct group and 19 of the 90 patients (21%) in the transferred group. Nine of the 19 deaths in the transferred group were ascribed to potential transfers. After adjusting for prehospital Revised Trauma Score (RTS) and ISS, the odds ratio of death was 2.40 (95%CI: 1.07–5.40) for patients in the transfer group. When potential transfer patients were excluded from the analysis, the adjusted odds ratio of death was 1.14 (95%CI: 0.43–3.01).ConclusionsAfter adjusting for survivor bias by including potential transfers, the results of this study suggest a lower risk of death for patients who are directly transported to a level I trauma centre than for patients who receive primary treatment in a level II or III centre and are transferred to a trauma centre. However, this finding was only significant when adjusting for survival bias and therefore we conclude that it is still uncertain if there is a lower risk of death for patients who are transported directly to a level I trauma centre.     

Does arrival time affect outcomes among severely injured blunt trauma patients at a tertiary trauma centre?

Background and aimsWe aimed to determine whether the outcome of severely injured patients differs based on admission time (office hours vs. non-office hours) at a tertiary trauma centre without an in-house trauma surgeon consultant available at all times. We also studied subgroups of patients presenting with a New Injury Severity Score (NISS) ≥ 25 and patients experiencing major bleeding.Patients and methodsThis trauma registry study consisted of severely injured patients (NISS > 15) with blunt trauma treated between 2006 and 2017 at a single institute. Causes of deaths were obtained from autopsy reports and classified as resulting from brain injury; exsanguination; multi-organ failure, adult respiratory distress syndrome, or sepsis; or other.ResultsAmong 1853 patients, 497 (27%) were admitted during office hours (OH) and 1356 (73%) during non-office hours (NOH). Further subgroup analysis consisted of 211 OH and 611 NOH patients with NISS ≥ 25, and 51 OH and 154 NOH patients experiencing major bleeding. The 30-day in-hospital mortality was 3.8%–7.4% lower in the NOH groups. We found no significant differences between the study groups in neither the standardised mortality ratio (SMR, defined as the ratio of observed to expected mortality) nor in the causes of death. In both groups, the primary cause of death resulted from brain injury.ConclusionsWe found that arrival time did not affect mortality among patients with severe blunt trauma treated at a tertiary trauma centre without an in-house trauma surgeon consultant available at all times. Thus, this type of unit can maintain a standard of care during non-office hours by investing in precise treatment protocols and continuous education. However, our results do not apply to penetrating trauma injury patients.     

Timing of tracheostomy and outcome of patients requiring mechanical ventilation

Objectives

To assess the impact of tracheostomy timing on outcome of critically ill patients requiring mechanical ventilation (MV).

Study design

Retrospective clinical study in a twelve beds intensive care unit (ICU).

Patients and methods

From January 2001 to June 2005, patients under MV who received tracheostomy were divided into 2 groups: early tracheostomy group when tracheostomy was performed before or on day 7 and late tracheostomy group when it was performed thereafter. We compared prevalence of nosocomial pneumonia, length of sedation, lengths of MV, length of stay in ICU, weaning from MV and mortality rates between the 2 groups.

Results

During this period of 4 years and half, 112 patients underwent tracheostomy, 62 of whom had early tracheostomy and 50 had late tracheostomy. Early tracheostomy was associated with significant reduction of length of sedation (10 ± 3 vs 17 ± 5 days, P < 0.001), length of MV (21 ± 19 vs 29 ± 17 days, P = 0.02) and length of stay in ICU (33 ± 22 vs 42 ± 18 days, P = 0.042). There were no differences in prevalence of pneumonia (21% for early tracheostomy group vs 31% for late tracheostomy group, P = 0, 13), weaning from MV (50 vs 36%, P = 0.19), and mortality rates between the 2 groups (38 vs 54%, P = 0.15).

Conclusion

This study demonstrated that early tracheostomy (≤ 7 days), was associated with shorter length of sedation, shorter duration of MV and shorter ICU length of stay, without affecting weaning from MV, prevalence of nosocomial pneumonia or survival.     

Oxygen delivery and consumption in head-injured and multiple trauma patients

Critically ill patients often demonstrate that whole body oxygen consumption (VO2) is dependent on oxygen delivery (DO2). In this retrospective study, the relationship of VO2 to DO2 in patients with isolated head injury (HI, n = 18) was compared to that in patients with multiple trauma (MT, n = 60) without serious head injury. Mean pulmonary capillary wedge pressure, central venous pressure, arterial PCO2, cardiac index, and oxygen delivery were significantly lower in HI, but oxygen consumption was not different in the groups. In both groups, changes in DO2 (delta DO2) within each patient were significantly correlated with changes in VO2 (delta VO2) in that same patient. This relationship was not different between the HI patients, (delta VO2 = (0.20 +/- 0.02) delta DO2), and the MT patients (delta VO2 = (0.17 +/- 0.01) delta DO2). When these groups were further divided into those with high hematocrit (greater than 32%) and low hematocrit (less than 32%), HI patients with a low hematocrit demonstrated a steeper regression slope, with 26 +/- 3% of the DO2 change being reflected in the VO2 change. This was significantly greater than the slope in HI patients with high hematocrit (13 +/- 3%) and the MT patients at high (19 +/- 2%) or low (16 +/- 2%) hematocrits. These data show a correlation between changes in oxygen delivery and consumption that is similar in both head-injury patients and multiple trauma patients without serious head injury. This relationship was greatest in head-injured patients at low hematocrit. This relationship of VO2 and DO2 in both groups suggests an influence of neurohumoral factors rather than local tissue phenomena.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nitrogen requirements in severely injured patients

The study was designed to evaluate nitrogen needs in severely injured patients during the first week after trauma. Thirty-nine patients aged from 18 to 65 years with a burn or fractures of more than two long bones were studied. Energy requirements were given parenterally as fat and glucose in isocaloric amounts. The patients were randomized into five groups receiving different amounts of nitrogen from zero to 0.3 g kg body-weight-1 24 h-1. Daily and cumulative nitrogen balance, urinary 3-methylhistidine excretion and nitrogen retention were calculated on days 2-8 after trauma. With no nitrogen, the mean(s.e.m.) daily nitrogen balance after the trauma was -13.8(0.5) gN. The balance improved markedly in groups with a nitrogen intake of up to 0.2 g kg body-weight-1 (P less than 0.001) compared with the no-nitrogen group. The 3-methylhistidine excretion increased because of the trauma in all groups with no statistically significant difference between the groups. Nitrogen retention decreased with increase in nitrogen supply and with time after injury. It is suggested that a nitrogen supply of 0.20 kg bodyweight-1 24 h-1 is optimal for severely injured patients during the first week after trauma.