Surgery induces human mononuclear cell arginase I expression

BACKGROUND

Arginase is a metabolic enzyme for the amino acid arginine that participates in the immune response to trauma. We hypothesize that surgical trauma induces arginase expression and activity in the human immune system.

METHODS

Peripheral mononuclear cell (MNC) arginase activity and expression and plasma nitric oxide metabolites and interleukin (IL)-10 were measured in patients undergoing elective general surgery. Twenty-two healthy volunteers served as a comparison population.

RESULTS

MNC arginase activity increased within 6 hours of surgery (p < 0.05) and coincided with increased arginase I protein expression. Plasma nitric oxide metabolites decreased significantly postoperatively (p < 0.05). Patients lacking an elevation in IL-10 failed to demonstrate increased MNC arginase activity.

CONCLUSION

Increased MNC arginase expression may contribute to postsurgical immune dysfunction by affecting arginine use and availability and nitric oxide metabolism in the immune system. Plasma IL-10 may play a role in regulating MNC arginase activity.

The routine use of sonography in penetrating torso injury is beneficial

BACKGROUND

Torso sonography (focused assessment with sonography for trauma [FAST]) has been added to our protocols for the evaluation of penetrating torso injury. The purpose of this study was to evaluate our recent experience and determine whether the use of FAST is beneficial.

METHODS

From January 1999 to January 2000, patients with penetrating torso injury and no clinical indication for surgery were evaluated by sonography with a selective use of other investigations. FAST consisted of sonographic views of the peritoneum and/or pericardium to determine the presence or absence of fluid.

RESULTS

During the study period, there were 238 victims of penetrating injury assessed by our trauma service, and sonography was performed in 72 (30%) patients as per our protocols. There were 31 stab, 37 gunshot/shotgun and, and 4 puncture wounds. Thirty-eight patients had peritoneal views, 6 patients had pericardial views, and 28 patients had both pericardial and peritoneal views obtained. Thirteen of 66 patients had free fluid in the peritoneal cavity and 12 of the 13 patients had a therapeutic laparotomy. No peritoneal fluid was seen in 53 of 66 patients, of whom 6 had abdominal injuries, 5 requiring surgery for diaphragm or bowel injuries. The sensitivity of FAST alone for abdominal injury was 67%, specificity was 98%, positive predictive value was 92%, and negative predictive value was 89%. Pericardial fluid was seen in 3 of 34 patients; one had a heart wound and two had negative pericardial windows. All 31 patients without pericardial fluid recovered without surgery.

CONCLUSION

The routine use of sonography in penetrating torso injury is beneficial. The detection of pericardial or peritoneal fluid is clinically useful. However, a negative FAST examination does not exclude abdominal injury, such as a diaphragm or hollow viscus wound, and further investigation or close follow-up is required.

Blunt abdominal aortic trauma in association with thoracolumbar spine fractures

All patients with blunt abdominal aortic disruption (BAAD) in the trauma registries at the three Regional Trauma Centres were retrospectively reviewed over the last decade. From the 11465 trauma admissions ISS>16,194 sustained aortic injuries. Eight cases of BAAD were identified, six with concurrent thoracolumbar spine (TLS) fractures (mean ISS 42). Patients with BAAD and TLS were subject to a detailed analysis. Clinically, three injury types were seen, hemodynamically unstable (uncontained full thickness laceration), stable symptomatic (intimal dissection with occlusion), and stable asymptomatic (contained full thickness laceration or intimal dissection without occlusion). All spinal column fractures involved a distractive mechanism, one with both distractive and translational fracture components. We propose that a distractive force, applied to the aorta lying anterior to the anterior longitudinal ligament, results in an aortic injury spectrum ranging from an intimal tear to a full thickness laceration, as a related injury. Computed tomography (CT) was an important imaging modality in the stable asymptomatic patients. All intimal dissections without occlusion were managed non-operatively. With distractive TLS fractures, BAAD needs to be considered.

Alterations in arginine metabolic enzymes in trauma

Arginine is the sole substrate for nitric oxide (NO) synthesis by NO synthases (NOS) and promotes the proliferation and maturation of human T-cells. Arginine is also metabolized by the enzyme arginase, producing urea and ornithine, the precursor for polyamine production. We sought to determine the molecular mechanisms regulating arginase and NOS in splenic immune cells after trauma. C3H/HeN mice underwent laparotomy as simulated moderate trauma or anesthesia alone (n = 24 per group). Six, 12, 24, or 48 h later, 6 animals from each group were sacrificed, and splenectomy was performed and plasma collected. Six separate animals had neither surgery nor anesthesia and were sacrificed to provide resting values (t = 0 h). Spleen arginase I and II and iNOS mRNA abundance, arginase I protein expression, and arginase activity were determined. Plasma NO metabolites (nitrite + nitrate) were also measured. Trauma increased spleen arginase I protein expression and activity (P = 0.01) within 12 and for at least 48 h after injury and coincided with up-regulated arginase I mRNA abundance at 24 h. Neither arginase II nor iNOS mRNA abundance in the spleen was significantly increased by trauma at 24 h. Plasma nitrite + nitrate was decreased in animals 48 h post-injury compared to anesthesia controls (P < 0.05). Trauma induces up-regulation of arginase I gene expression in splenic immune cells within 24 h of injury. Arginase II is not significantly up-regulated at that time point. Arginase I, rather than iNOS appears to be the dominant route for arginine metabolism in splenic immune cells 24 h after trauma.

Arginase I expression and activity in human mononuclear cells after injury

OBJECTIVE

To determine the effect of trauma on arginase, an arginine-metabolizing enzyme, in cells of the immune system in humans.

SUMMARY BACKGROUND DATA

Arginase, classically considered an enzyme exclusive to the liver, is now known to exist in cells of the immune system. Arginase expression is induced in these cells by cytokines interleukin (IL) 4, IL-10, and transforming growth factor beta, corresponding to a T-helper 2 cytokine profile. In contrast, nitric oxide synthase expression is induced by IL-1, tumor necrosis factor, and gamma interferon, a T-helper 1 cytokine profile. Trauma is associated with a decrease in the production of nitric oxide metabolites and a state of immunosuppression characterized by an increase in the production of IL-4, IL-10, and transforming growth factor beta. This study tests the hypothesis that trauma increases arginase activity and expression in cells of the immune system.

METHODS

Seventeen severely traumatized patients were prospectively followed up in the intensive care unit for 7 days. Twenty volunteers served as controls. Peripheral mononuclear cells were isolated and assayed for arginase activity and expression, and plasma was collected for evaluation of levels of arginine, citrulline, ornithine, nitrogen oxides, and IL-10.

RESULTS

Markedly increased mononuclear cell arginase activity was observed early after trauma and persisted throughout the intensive care unit stay. Increased arginase activity corresponded with increased arginase I expression. Increased arginase activity coincided with decreased plasma arginine concentration. Plasma arginine and citrulline levels were decreased throughout the study period. Ornithine levels decreased early after injury but recovered by postinjury day 3. Increased arginase activity correlated with the severity of trauma, early alterations in lactate level, and increased levels of circulating IL-10. Increased arginase activity was associated with an increase in length of stay. Plasma nitric oxide metabolites were decreased during this same period.

CONCLUSIONS

Markedly altered arginase expression and activity in cells of the human immune system after trauma have not been reported previously. Increased mononuclear cell arginase may partially explain the benefit of arginine supplementation for trauma patients. Arginase, rather than nitric oxide synthase, appears to be the dominant route for arginine metabolism in immune cells after trauma.

Utilization of FAST (Focused Assessment with Sonography for Trauma) in 1999: results of a survey of North American trauma centers

Although much has been written about FAST (Focused Assessment with Sonography for Trauma) in the last decade little is known about its present clinical utilization. The purpose of this study was to evaluate and characterize the contemporary utilization of FAST at trauma centers in the United States and Canada. In 1999 trauma directors or their delegates at Level I regional trauma centers in the United States and Canada were surveyed either by fax or phone regarding the present utilization and the future of FAST at their center. The overall survey response rate was 91 per cent with 96 of 105 centers completing the survey. Of the 96 centers surveyed 78 were in the United States and 18 were in Canada. Of the 78 U.S. centers surveyed 62 (79%) routinely use FAST, and it is done by surgeons in 39 per cent, surgeons and emergency departments in 21 per cent, emergency departments in 5 per cent, and radiologists in 35 per cent. Most centers (79%) thought that it sped up their workups, and 89 per cent said it was an advance in patient care. FAST is used in penetrating injury at 58 per cent of centers, and some centers use FAST to assess organ injury. The utilization of diagnostic peritoneal lavage and CT has markedly decreased at many centers. Almost all respondents thought that FAST should be a component of surgery resident training. The utilization of FAST is significantly less in Canada than in the United States (P < 0.05). Our conclusions are the following. FAST has become routinely used at the majority of the U.S. centers surveyed. FAST is performed by clinicians at 65 per cent of the trauma centers surveyed. The utilization of CT and diagnostic peritoneal lavage has changed. Many centers have broadened the scope of FAST to include the assessment of organ, pediatric, and penetrating injury.

Is clinical examination an accurate indicator of raised intra-abdominal pressure in critically injured patients?

OBJECTIVES

To determine the rate of elevated intra-abdominal pressure (IAP) and to evaluate the accuracy of clinical abdominal examination in the assessment of IAP in the critically injured trauma patient.

DESIGN

A prospective blinded study.

SETTING

The medical-surgical critical care unit of a university-affiliated regional adult trauma centre.

PATIENTS

Forty-two adult blunt trauma victims, who had a mean injury severity score of 36.

INTERVENTIONS

Urinary bladder pressure was measured daily and classified as normal (10 mm Hg or less), elevated (more than 10 mm Hg) or significantly elevated (more than 15 mm Hg). A blinded clinical assessment of abdominal pressure was concurrently performed and recorded as elevated or normal.

MAIN OUTCOME MEASURES

The sensitivity, specificity and accuracy and the positive and negative predictive values of the 2 interventions in identifying elevated IAP.

RESULTS

Twenty-one patients (50%) had an elevated IAP at some point during the study. Of the 147 bladder pressure measurements done in these 42 patients, 47 (32%) were more than 10 mm Hg and 16 (11%) were more than 15 mm Hg. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of clinical abdominal examination for identifying elevated IAP were 40%, 94%, 76%, 77% and 77%, respectively. Clinical abdominal examination had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 56%, 87%, 35%, 94% and 84% respectively, for significantly elevated IAP.

CONCLUSIONS

Urinary bladder pressure was commonly elevated among our population of critically injured adults. Compared with bladder pressure measurements, clinical abdominal assessment showed poor sensitivity and accuracy for elevated IAP. These findings suggest that more routine measurements of bladder pressure in patients at risk for intra-abdominal hypertension should be performed.

A single-center 8-year experience with percutaneous dilational tracheostomy

OBJECTIVE

To determine surgical, postoperative, and postdischarge complications associated with percutaneous dilational tracheostomy (PDT) in an 8-year experience at the University of Kentucky.

SUMMARY BACKGROUND DATA

There are known risks associated with the transport of critically ill patients to the operating room for elective tracheostomy, and less-than-optimal conditions may interfere with open bedside tracheostomy. PDT has been introduced as an alternative to open tracheostomy. Despite information supporting its safety and utility, the technique has been criticized because advocates had not provided sufficient information regarding complications.

METHODS

A prospective database was initiated on all patients who underwent PDT between September 1990 and May 1998. The database provided indication, procedure time, duration of intubation before PDT, and intraoperative and postoperative complications. Retrospective review of medical records and phone interviews provided long-term follow-up information.

RESULTS

In the 8-year period, 827 PDTs were performed in 824 patients. Two patients were excluded because PDT could not be completed for technical reasons. There were 519 male and 305 female patients. Mean age was 56 years. Prolonged mechanical ventilatory support was the most common indication. Mean procedure time was 15 minutes, and the average duration of intubation before PDT was 10 days. The intraoperative complication rate was 6%, with premature extubation the most common complication. The procedure-related death rate was 0.6%. Postoperative complications were found in 5%, with bleeding the most common. With a mean follow-up of greater than 1 year, the tracheal stenosis rate was 1.6%.

CONCLUSIONS

On the basis of this large, single-center study, the authors conclude that when performed by experienced surgeons, PDT is a safe and effective alternative to open surgical tracheostomy for intubated patients who require elective tracheostomy.

Trauma increases extrahepatic arginase activity

BACKGROUND

Although expressed primarily in the liver, arginase activity also is present in extrahepatic tissues and specifically in macrophages, where it may play diverse physiologic roles in wound healing, cellular proliferation, and the regulation of nitric oxide production. Arginase activity in immune cells is upregulated by certain cytokines such as IL-4, IL-10, and TGF-beta and by catecholamines. Since the release of these substances is increased after trauma, we hypothesized that arginase activity would also be increased in immune cells after trauma. The current work tests this hypothesis.

METHODS

A model of surgical trauma was created in C3H/HeN mice by performing an exploratory laparotomy. Tissue arginase activity and arginase I protein expression were determined. As a control, arginase activity and expression were also stimulated with the use of endotoxin. In addition, we evaluated the expression of inducible nitric oxide synthase and the accumulation of nitric oxide metabolites in plasma.

RESULTS

Surgical trauma was associated with a significant increase in arginase activity in splenic and renal tissues (P < .05). Splenic macrophages from trauma animals exhibited arginase activity levels approximately 10 times those of controls (P < .05). Endotoxin alone increased arginase activity in the spleen, but this increase was less than that of trauma alone (P < .05). Arginase activity remained elevated after trauma for up to 4 days and normalized by day 7. Arginase I expression was upregulated by trauma in both splenic and renal tissue and by endotoxin in the spleen only. Despite upregulation of inducible nitric oxide synthase in trauma animals, circulating nitric oxide metabolites were decreased 2 days after trauma compared with controls (P < .05). Endotoxin-induced nitric oxide metabolites were also reduced in trauma animals compared with endotoxin treatment alone (P < .05), but this normalized by day 4.

CONCLUSIONS

Extrahepatic arginase expression and activity is increased after trauma and may provide the necessary precursors for cellular proliferation and repair or may play a regulatory role in the production of nitric oxide.

Beta adrenoceptor regulation of macrophage arginase activity

BACKGROUND

Arginase, which metabolizes L-arginine within the urea cycle, is essential for production of polyamines and affects production of nitric oxide by depletion of L-arginine, the common substrate for both arginase and nitric oxide synthase. Having shown that trauma increases splenic macrophage arginase activity, we seek to define the mechanisms for this. RAW macrophage arginase activity and expression are increased by 8-bromo-cAMP in vitro. We hypothesize that since catecholamines increase cAMP, trauma-induced splenic arginase activity may be mediated by post-injury catecholamine release.

METHODS

RAW 264.7 macrophage arginase activity was measured in vitro in response to 4 catecholamines with or without propranolol or lipopolysaccharide (LPS). C57BL/6 mice underwent laparotomy as a model of moderate trauma after propranolol treatment, with and without intraperitoneal Escherichia coli LPS administration as a simulated pro-inflammatory stimulus.

RESULTS

Macrophage arginase activity increased in vitro in response to catecholamines or LPS (P < .05). Propranolol pretreatment blocked macrophage arginase activity induced by epinephrine (10 mumol/L) in vitro (P < .05). Trauma or LPS alone increased splenic arginase activity in vivo (P < .05). Propranolol did not alter LPS-induced splenic arginase activity but did significantly reduce trauma-induced splenic arginase activity (P < .05).

CONCLUSIONS

Catecholamines alone increase macrophage arginase activity through beta-adrenoceptor activation. Increased splenic arginase activity induced by moderate trauma is decreased by beta-adrenoceptor blockade, suggesting that trauma-induced arginase activity is partly mediated by endogenous catecholamines.

A minimally invasive approach to bile peritonitis after blunt liver injury

The advent of nonoperative management of liver injuries has made it imperative that surgeons be familiar with the potential delayed complications of this approach. In this report, we describe a minimally invasive strategy for the management of bile peritonitis following nonoperative management of blunt liver injuries. Two cases are presented in which bile peritonitis with massive bile ascites was managed with laparoscopic localization and drainage of the bile leak, irrigation of the peritoneal cavity, and postoperative endoscopic retrograde cholangiography with bile duct stenting. In both cases the bile leak ceased, and the patients recovered without adverse sequelae. The combination of laparoscopic surgery and endoscopic stenting provides a minimally invasive approach to this entity.

Sonographic assessment of traumatic injury. Future developments

In all its forms and applications, sonography plays a significant role in the management of injured patients, from the emergency department to beyond hospital discharge. The use of new and existing sonographic technology will increase because sonographic imaging and measurements are generally less invasive; are inexpensive; use no ionizing radiation; and are portable, repeatable, and, in many instances, as accurate as the so-called "contemporary gold standards." The training and credentialing of physicians in sonography is in evolution and will be an increasingly important issue with more widespread use and broader applications. The future of sonography in trauma care in the next millennium is bright, and surgeons and surgical residents are encouraged to gain proficiency and learn about this new surgical frontier as it evolves.

Prospective evidence of the superiority of a sonography-based algorithm in the assessment of blunt abdominal injury

BACKGROUND

Although the routine use of FAST (focused assessment with sonography for trauma) in the evaluation of trauma victims is increasing, to our knowledge, a prospective comparison of contemporary adult trauma victims managed with and without FAST has not been reported in North America.

METHODS

Adult victims of blunt trauma for whom there was a suspicion of abdominal injury were managed with one of two diagnostic algorithms, FAST or no-FAST. The two algorithms were compared for diagnostic accuracy, cost, time, and delayed diagnoses.

RESULTS

Among 706 patients (mean Injury Severity Score, 23), 460 were managed with FAST and 246 with no-FAST. The two groups were similar with respect to age, Injury Severity Score, prehospital time, and mortality (p = not significant). There were 3 of 460 (0.7%) delayed diagnoses in the FAST group and 4 of 246 (1.6%) in the no-FAST group (p = not significant). The diagnostic accuracy for the FAST and no-FAST algorithms was 99% and 98%, respectfully. The FAST and no-FAST algorithms led to similar rates of laparotomy, 13% and 14%, respectfully, but nonoperative management was more common in the no-FAST group (p < 0.01). The mean diagnostic cost for the FAST algorithm was $156, compared with $540 with the no-FAST algorithm (p < 0.0001) and the mean time required for diagnostic work-up was 53 minutes with the FAST algorithm, compared with 151 minutes with the no-FAST algorithm (p < 0.0001).

CONCLUSION

This study has provided prospective evidence that a FAST-based algorithm for blunt abdominal injury was more rapid, less expensive, and as accurate as an algorithm that used computed tomography or diagnostic peritoneal lavage only. Trauma centers are encouraged to incorporate a FAST-based algorithm into their initial management of blunt trauma victims.

Prospective evaluation of the potential role of teleradiology in acute interhospital trauma referrals

BACKGROUND

Teleradiology is one form of telemedicine that would allow the transmission of radiographs before the transfer of acutely traumatized patients between referring and receiving hospitals. The purpose of this study was to evaluate the potential impact of a prehospital teleradiology system on trauma patient management and transfer.

METHODS

Forty-four injured adults referred to a trauma center were included. The history, physical examination, and radiographic findings reported by the referring physician to the receiving physician were documented. The plain radiographs of the chest, pelvis, and cervical spine taken at the referring hospital were obtained after patient transfer. For each case, two reviewers blinded to the case (surgeon [S] and emergency department physician [E]) and one reviewer not blinded to the case were individually presented with the referring physician's report and the radiographs. The reviewers were surveyed as to the implications of viewing the plain radiographs taken at the referring hospital before patient transfer.

RESULTS

Overall, the blinded reviewers felt that viewing the radiographs before transfer would have influenced care in 40% and 38% of cases as judged by (S) and (E), respectively, with a crude agreement of 67.5% (kappa level, 0.32). The blinded reviewers (S and E) commonly noted the following four changes in management as a result of viewing the referred radiographs: requested further clinical history (S, 18%; E, 23%), suggested further pretransfer interventions (S, 38%; E, 30%), suggested further pretransfer diagnostic tests (S, 25%; E, 13%), and emphasized precautions during transfer (S, 28%; E, 30%). The nonblinded reviewer suggested potential influence in the management of at least 65% of the cases.

CONCLUSION

This study suggests that viewing the radiographs of acutely injured trauma patients has the potential to influence many aspects of the management of interhospital transfer.

Early detection of hemoperitoneum by ultrasound examination of the right upper quadrant: a multicenter study

BACKGROUND

The focused assessment for the sonographic examination of the trauma patient (FAST) is a rapid diagnostic test that sequentially surveys for hemopericardium and then the right upper quadrant (RUQ), left upper quadrant (LUQ), and pelvis for hemoperitoneum in patients with potential truncal injuries. The sequence of the abdominal part of the examination, however, has yet to be validated. The objectives of this multicenter study were as follows: (1) to determine where hemoperitoneum is most frequently identified on positive FAST examinations; and (2) to determine if a relationship exists between that areas and the organs injured.

METHODS

Ultrasound registries from four Level I trauma centers identified patients who had true-positive FAST examinations. Demographic data, areas positive on the FAST, and organs injured were recorded; injuries were classified as multiple, single solid organ (liver or spleen), isolated hollow viscus, or retroperitoneal. Relationships between positive locations on the FAST examinations and the associations of organs injured to areas positive were assessed using McNamara's chi2 test; a p value < 0.05 was considered statistically significant.

RESULTS

The RUQ was the most common site where hemoperitoneum was detected, and this was statistically significant compared with either the LUQ or the pelvis. Also, statistically significant correlations (p < 0.001) were observed between positive RUQ areas on the FAST and multiple injuries, single solid organ (liver or spleen) injury, and retroperitoneal injuries.

CONCLUSION

Blood is most often found on the FAST in the RUQ area in patients with multiple intraperitoneal injuries or isolated injury to the liver, spleen, or retroperitoneum, but not when there is injury to a hollow viscus.

The indeterminate abdominal sonogram in multisystem blunt trauma

BACKGROUND

North American trauma centers are beginning to note the limitations of emergent torso sonography. The purpose of this prospective study was to evaluate the frequency, causes, associations, and sequelae of indeterminate (IND) sonograms in blunt trauma.

METHODS

Among adult blunt trauma patients assessed with screening torso sonography, clinician sonographers recorded the abdominal sonogram as positive, negative, or IND for free fluid. Patients with IND sonograms were further investigated with repeat sonography, computed tomography, or diagnostic peritoneal lavage.

RESULTS

Among 417 patients with blunt trauma (mean Injury Severity Score = 21) managed with sonography, there were 28 (6.7%) IND and 389 (93.3%) non-IND sonograms. Sonograms were IND because of patient factors in 71% (20 of 28) and because of operator factors in 29% (8 of 28). None of the 28 patients were managed with repeat sonography alone. All 4 diagnostic peritoneal lavage examinations gave negative results, whereas 8 of 23 computed tomographic scans were abnormal (6 of 8 patients underwent laparotomy). The mean time required for diagnostic workup was 117 minutes in the IND group and 48 minutes in the non-IND group (p < 0.001 in both cases).

CONCLUSION

This prospective study has demonstrated that IND sonograms are not common at our center (6.7%), are usually attributable to patient factors, and are associated with greater diagnostic time. Patients with IND sonograms require further investigation because they often have injuries requiring laparotomy.

Measuring injury severity: time for a change?

BACKGROUND

The Injury Severity Score (ISS) does not take into account multiple injuries in the same body region, whereas a New ISS (NISS) may provide a more accurate measure of trauma severity by considering the patient's three greatest injuries regardless of body region. The purpose of this study was to evaluate the ISS and NISS in patients with blunt trauma.

METHODS

Consecutive individuals treated from January of 1992 to September of 1996 at one institution were included if they had sustained blunt trauma and satisfied triage standards (n = 2,328). For each patient, we computed the ISS and the NISS to determine how often the two scores were identical or discrepant. Discrepant cases were then further analyzed using receiver operating characteristic curves to determine which score better predicted short-term mortality.

RESULTS

The mean ISS was 25 +/- 13, and the mean NISS was 33 +/- 18. The two predictive scores were identical in 32% of patients and discrepant in 68% of patients. Patients with identical scores had a lower mortality rate than patients with discrepant scores (10% vs. 13%; p < 0.02). In patients with discrepant scores, the area under the receiver operating characteristic curves was greater for the NISS than the ISS (0.852 vs. 0.799; p < 0.001), and greater amounts of discrepancy were associated with increasing rates of mortality (p < 0.001).

CONCLUSIONS

The NISS often increases the apparent severity of injury and provides a more accurate prediction of short-term mortality. The benefit associated with using the NISS rather than the ISS must be weighed against the disadvantages of changing a scoring system and the potential for still greater improvements.

Changes in red cell transfusion practice among adult trauma victims

BACKGROUND

Recent attention concerning the adverse outcomes of blood transfusion has resulted in decreased blood product usage for nonemergency care. We hypothesized that there has also been a decrease in blood product use in the management of seriously injured adults.

METHODS

A retrospective review of institutional database records was conducted at a regional trauma center for adults admitted during 1991, 1993, and 1995. Data was analyzed for trends in amount, type, and timing of blood product use.

RESULTS

A total of 1,738 patients were assessed, with 1,605 meeting inclusion. The three patient groups were similar, including injury severity (overall mean Injury Severity Score of 23.6), mechanism (88% blunt), and survival (87%). In 1991, 54% of the patients were transfused a total of 2,341 units of packed red blood cells (mean 4.67 units/pt treated) versus 42% of patients in 1995 (p < 0.0001) who received 2,018 packed red blood cells (mean 3.57 units/patient treated, p = 0.05). A significantly higher proportion of units was transfused in the first 24 hours of care in 1995 (64%) compared with 1991 (21%, p < 0.0001). A reduction in the use of universal donor type-O blood use was also found (1.21 vs. 0.65 units/patient transfused, p < 0.0001). Despite similar admission hemoglobin concentrations (124.1 vs. 125.3, not significant), significant reductions were found in the average 24-hour (109.2 vs. 103.8, p < 0.001), lowest (96.5 vs 92.1, p < 0.01) and discharge (115.8 vs. 110.5, p < 0.001) concentrations.

CONCLUSIONS

Between 1991 and 1995 there have been significant reductions in both the number of trauma patients receiving blood products and the total number of units transfused. These findings may reflect lower or abandoned hemoglobin transfusion triggers and increased awareness of complications related to transfusion.

The abdominal compartment syndrome

The abdominal compartment syndrome refers to the alterations in respiratory mechanics, hemodynamic parameters and renal function that occur as a result of a sustained increase in intra-abdominal pressure. The syndrome may follow a diverse series of insults, including laparotomy for severe abdominal trauma, ruptured abdominal aortic aneurysm and intra-abdominal infection. Diagnosis depends on recognizing the clinical picture in patients at risk, followed by an objective measurement of intra-abdominal pressure. Successful management may require abdominal decompression with temporary abdominal closure. Despite urgent decompression, the death rate is high because of the severity of the patients' underlying illness.

Thoracic trauma and early intramedullary nailing of femur fractures: are we doing harm?

INTRODUCTION

It has been reported that early intramedullary nailing (IMN) of a femur fracture in the presence of thoracic injury increases morbidity and mortality. The purpose of the present study was to determine if IMN < or = 24 hours after multisystem injury (Injury Severity Score (ISS) > 16) is associated with a poor hospital outcome in the presence of blunt thoracic trauma (Abbreviated Injury Scale (AIS) thorax score > or = 2).

METHODS

Retrospective cohort study at a single adult trauma center.

RESULTS

In a 6-year period, 149 blunt trauma patients had both an ISS > 16 and a femur fracture managed by IMN. These 149 patients were divided into four groups based on thoracic injury (T = AIS thorax score > or = 2; N = AIS thorax score < 2) and the timing of IMN (E = < or = 24 hours; L = > 24 hours). There were 68 TE, 57 NE, 15 TL, and 9 NL patients. The TE and NE groups were similar in age and ISS. TE and NE groups had similar durations of ventilation, critical care, hospital stay, and mortality. Furthermore, TE patients were no more likely to be intubated after IMN than NE patients. TE patients were matched with similar patients without a femur fracture and found to have similar hospital outcomes.

CONCLUSIONS

This study has not demonstrated an increased morbidity or mortality associated with early IMN in the presence of thoracic trauma.

Lateral impact motor vehicle collisions: significant cause of blunt traumatic rupture of the thoracic aorta

BACKGROUND

This study was undertaken to determine the relationship between traumatic rupture of the thoracic aorta (TRA) and the direction of impact at the time of motor vehicle crash.

METHODS

Retrospective review of TRA patients from two different databases over a 4.5-year period (January 1, 1991 to June 30, 1995): (1) Ontario Coroner's Office records of motor vehicle deaths from Metropolitan Toronto, and (2) the trauma registries of Sunnybrook Health Science Centre and St. Michael's Hospital in Metropolitan Toronto.

RESULTS

Ninety-seven patients (81 from the coroner's database and 16 from the adult trauma unit registries) sustained traumatic rupture of the thoracic aorta. Forty-eight cases (49.5%) were a result of lateral impact crashes. Twenty-eight drivers (22 ipsilateral and six contralateral) and 20 passengers (16 ipsilateral and four contralateral) sustained TRA from lateral impact crashes. Ninety-one TRAs (94%) occurred at the peri-isthmic region.

CONCLUSION

Lateral impact crashes are a significant cause of TRA. Traumatic rupture of the aorta should be considered with a high index of suspicion after serious lateral impact crashes, just as physicians now consider patients at high risk of TRA after serious frontal impact crashes.

Long-term outcomes in open pelvic fractures

BACKGROUND

Open pelvic fractures represent one of the most devastating injuries in orthopedic trauma. The purpose of this study was to document the injury characteristics, complications, mortality, and long-term, health-related quality of life outcomes in patients with open pelvic fractures.

METHODS

The trauma registry at an adult trauma center was used to identify all multiple system blunt trauma patients with a pelvic fracture from January of 1987 to August of 1995 (n = 1,179). Demographic data, mechanism of injury, and fracture type were determined from hospital records. Short-term outcome measures included infectious complications, mortality, and length of stay in hospital. Long-term outcomes of survivors were obtained by telephone interview using the SF-36 Health Survey and the Functional Independence Measure.

RESULTS

Open pelvic fractures were uncommon, occurring in 44 patients (4%). Patients with open fractures were about 9 years younger, on average, than patients with closed fractures (30 vs. 39, p < 0.001). Similarly, patients with open fractures were more likely to be male (75 vs. 57%, p < 0.02), more likely to have been involved in a motorcycle crash (27 vs. 6%, p < 0.001), and more likely to have an unstable pelvic ring disruption (45 vs. 25%, p < 0.001). Open pelvic fracture patients required more blood than closed pelvic fracture patients, both in the first day (16 vs. 4 units, p < 0.001) and during the total hospital admission (29 vs. 9 units, p < 0.001). Five patients with perineal wounds did not receive a diverting colostomy; in turn, these individuals had a total of six pelvic infectious complications (one abscess, two with osteomyelitis, and three perineal wound infections). Overall, 11 patients died, six patients were lost to follow-up, and 27 were long-term survivors (mean duration of 4 years). Chronic disability was common after a pelvic fracture, with problems related to physical role performance and physical functioning, and was particularly severe after an open pelvic fracture (p < 0.05 for both as measured by the SF-36).

CONCLUSIONS

Patients with open pelvic fractures often survive, need to be treated with massive blood transfusions, and often require a colostomy. They are frequently left with chronic pain and residual disabilities in physical functioning and physical roles, and many remain unemployed years after injury.

Long-term outcomes in blunt trauma: who goes back to work?

BACKGROUND

Trauma patients continue to improve after discharge from the trauma center, but the completeness of this recovery remains uncertain. The purpose of this study was to compare the characteristics of patients who do and who do not return to work after blunt trauma.

METHODS

Consecutive survivors of blunt trauma discharged from a regional trauma center over a 1-year interval (July of 1994 to June of 1995) were included in the study. Patients completed the SF-36 Health Survey and some additional questions related to employment status both at discharge and again after 1 year. Our principal analysis compared patients who were employed and unemployed at 1-year follow-up.

RESULTS

Complete data were available for 195 patients. The typical patient was a young man who had been in a motor vehicle collision and had an injury severity score of 25. At 1-year follow-up, 101 patients had returned to work and 94 remained unemployed. Employed individuals were younger (31 vs. 44 years, p < 0.0001), less severely injured (mean injury severity score 23 vs. 27, p < 0.001), and more likely to hold professional jobs (50 vs. 16%, p < 0.0001). Patterns of injury and operative procedures were similar for employed and unemployed patients. However, the average employed patient had fewer days in the intensive care unit (2 vs. 5 days, p < 0.001), a shorter total hospitalization (19 vs. 28 days, p < 0.01), and was more likely to be discharged to home (62 vs. 39%, p < 0.01). At discharge, those who went on to employment had marginally better SF-36 Health Survey scores on seven of the eight scales (all except general health). During the year after discharge, both groups improved significantly, although employed individuals to a greater extent on all scales of the SF-36 Health Survey.

CONCLUSIONS

Almost one half of the multiple system blunt trauma patients remain unemployed 1 year after hospital discharge. Those patients who return to work are usually young professionals with a lower severity of injury. Functional status at discharge predicts future employment status, but underestimates the extent of long-term recovery.

Chylothorax after blunt chest trauma: a report of 2 cases

Chylothorax is a rare complication of blunt chest trauma and is associated with fracture-dislocation of the thoracic spine in only 20% of these cases. Two cases of chylothorax after blunt chest injury are described in this paper; 1 was related to a fracture of the third thoracic vertebra. Closed chest drainage and total parenteral nutrition led to resolution of the condition within 3 weeks in both cases. In general, traumatic chylothorax should be managed conservatively for at least 4 weeks before surgical intervention is considered.

Hypotension after blunt abdominal trauma: the role of emergent abdominal sonography in surgical triage

OBJECTIVE

Trauma victims with hypotension require a rapid and reliable localization of bleeding and expedient surgical triage. Our hypothesis is that emergent abdominal sonography (EAS) is a rapid and accurate test of the need for urgent laparotomy in blunt trauma victims with hypotension.

METHODS

Among 400 blunt trauma victims entered in a prospective blind study of EAS, a subgroup of 69 (17%) patients had a systolic blood pressure < or = 90 mm Hg during their initial assessment. Although the EAS results [(+) = fluid, (-) = no fluid] were not used in clinical decision making, the potential contribution of EAS to patient care was examined.

RESULTS

The mean Injury Severity Score was 32. Twenty-two (32%) patients were EAS (+), of which 19 required an acute laparotomy. No laparotomies were performed in the 47 EAS (-) patients. The EASs required 19 +/- 5 seconds in the EAS (+) group and 154 +/- 13 seconds in the EAS (-) group. Twenty of the 22 positive EASs had free fluid in Morison's pouch. All 13 patients with an ultrasound score > or = 3 had a laparotomy. The primary etiology of hypotension was blood loss in 42 patients, hemoperitoneum in 18, and retroperitoneal hemorrhage in 12.

CONCLUSION

EAS is a rapid and accurate indicator of the need for urgent laparotomy in the hypotensive blunt trauma victim. Further, a negative EAS can hasten the search for other causes of hypotension. Diagnostic peritoneal lavage may become obsolete in centers with EAS capabilities.

Injury pattern and severity in lateral motor vehicle collisions: a Canadian experience

OBJECTIVE

To determine the pattern and severity of injury and the outcome of front seat motor vehicle occupants after lateral impact crashes.

DESIGN

Retrospective review undertaken in a Regional Trauma Unit (Sunnybrook Health Science Centre).

MATERIALS AND METHODS

Review of seriously injured front seat motor vehicle occupants admitted to a Regional Trauma Unit over a 46-month period (September 15, 1989, to July 15, 1993) for whom vehicle crash information and occupant seat belt use were known.

MEASUREMENTS AND MAIN RESULTS

Three hundred forty-eight front seat vehicle occupants were available for study; one hundred forty-one (41%) were involved in a lateral impact motor vehicle crash. Driver side lateral crashes (57%) were more common than passenger side impacts. Victims of lateral impact crashes had a significantly higher mean Injury Severity Score (25 compared with 20 for nonlateral crashes: p < 0.05), and the direction of impact was strongly associated with injury severity (p < 0.05). Lateral impact crashes resulted in substantially more significant chest (p < 0.01) and intra-abdominal (p < 0.0001) injuries. Type of injury was significantly different between the lateral and nonlateral impact groups for facial, chest, abdominal, and musculoskeletal injuries.

CONCLUSIONS

The direction of impact in motor vehicle crashes is strongly associated with the pattern and severity of organ injuries. Further attention to automobile safety design is necessary to better protect occupants involved in lateral impact crashes.

Emergent abdominal sonography as a screening test in a new diagnostic algorithm for blunt trauma

Although there is an interest in emergent abdominal sonography (EAS), the clinical utilization of EAS in North America is minimal. The purpose of this study was to develop a new diagnostic algorithm for blunt abdominal injury based on a prospective blinded comparison of EAS, diagnostic peritoneal lavage (DPL), and computed tomography (CT). EAS (+ = fluid, - = no fluid) was performed before the DPL or CT, in 400 patients with a mean Injury Severity Score of 26; 293 had a CT and 107 had a DPL. The EASs required 2.6 +/- 1.2 minutes with 82% < or = 3 minutes. The accuracy of EAS for free fluid was 94% with a positive and negative predictive value of 82 and 96%, respectively. Only 1 of 338 patients with EAS- had an acute therapeutic laparotomy. Three patients with EAS- had a delayed laparotomy based on evolving clinical findings. The radiologists interpretation of the EAS video disagreed with the clinician sonographer in only 3% of cases. Based on these results, a diagnostic algorithm was developed using EAS as a screening test with selective use of DPL and CT. Emergent abdominal sonography performed by clinician sonographers is a rapid and accurate test for peritoneal fluid in blunt trauma victims, and the need for laparotomy in patients with a negative EAS is rare. Our study supports the routine use of EAS as a screening test in a diagnostic algorithm for the evaluation of blunt abdominal trauma.

The lymphatic circulation plays a dynamic role in blood volume and plasma protein restitution after hemorrhage

The purpose of this study was to determine the contribution of the lymphatic circulation to blood volume and plasma protein restitution after hemorrhage. Splenectomized sheep were prepared with thoracic duct and vascular catheters. The day after surgery, thoracic duct lymph flow, thoracic duct lymph protein, plasma protein, mean arterial pressure, and blood volume were measured. After 12 h, awake sheep were either bled 25% of blood volume over 5 min (HEM; n = 6) or observed (SHAM; n = 5) and measurements were recorded for 48 h. In HEM, the thoracic duct protein return rate and thoracic duct lymph flow transiently decreased (0-.5 h) but were then equal to or greater than that in SHAM. In HEM, there was restitution of both blood volume and plasma protein mass approximately 12 h after hemorrhage. Both thoracic duct lymph flow and protein return rate are significant contributors to blood volume and plasma protein restitution after hemorrhage. These findings and the prior demonstration by the authors that lymphatic vessel pumping is increased after hemorrhage suggest a dynamic role for the lymphatic circulation in blood volume homeostasis after hemorrhage.

Trauma ultrasound workshop improves physician detection of peritoneal and pericardial fluid

Hemoperitoneum represents a major indication for surgical intervention after trauma. To improve the ability of surgical residents and trauma physicians to detect intraperitoneal and pericardial fluid using ultrasound as a diagnostic modality, we conducted a focused trauma ultrasound workshop consisting of discussion of ultrasound physics, demonstration of instrumentation, review of pertinent literature, videotaped demonstration, and "hands-on" teaching of the skills utilizing live patient models. The ultrasound probes were placed in four standard locations--right and left upper quadrants, epigastrium, and Pouch of Douglas. Skills acquisition was tested by pre- and postworkshop performance on 12 sonograms (3 for each location, 6 were positive for fluid). Thirty physicians (21 residents and 9 staff: Group I) who attended the workshop were compared to 30 matched controls (Group II). The results (means +/- SD) were as follows (R = number right, I = number of "indeterminate," W = number of wrong responses out of 12, *P < 0.05 compared to Group II): [Table: see text] False positive (%) and false negative (%) decreased from 12.9 +/- 1.5 to 8.9 +/- 5.3 and 15.0 +/- 10.4 to 5.0 +/- 5.2, respectively, in Group I but did not change in Group II. Postworkshop ability to detect fluid was significantly (P < 0.05) improved, with no major differences between residents and staff. Our data suggest that these workshops can significantly improve the skills of nonradiologists in sonographic identification of pericardial and intraperitoneal fluid and should therefore be considered an essential component of ultrasound training for trauma physicians.

Blunt abdominal trauma

Assessment and management of patients with blunt abdominal trauma remains a challenge for emergency physicians. The spectrum of injury ranges from the trivial to the catastrophic and the initial assessment, resuscitation, and investigation of patients with abdominal trauma must be individualized. This article covers the important aspects of patient history and physical examination and addresses the relevant investigative tools available. An approach to the assessment of patients with abdominal trauma is provided; the goal is to diagnose significant injuries as soon as possible and avoid the pitfall of a delayed or missed diagnosis.

Post-traumatic small-bowel stricture: a case report

The use of lap seat belts has recently been recognized as a mechanism of blunt injury to the small bowel. Patients usually present immediately after injury and require urgent laparotomy. An unusual case of delayed small-bowel stricture after conservative management of an injury resulting from blunt trauma is reported. A 37-year-old woman involved in a high-speed motor vehicle accident was managed in hospital by observation. She had abdominal distension and pain, which gradually decreased and allowed slow introduction of a liquid diet. She was discharged from hospital but returned 6 weeks after injury with pain, abdominal distension, vomiting and obstipation. Stricture of an 8-cm segment of distal jejunum was found. Resection of the involved segment with primary anastomosis was curative.

Lower airway injuries and anaesthesia

PURPOSE

The perioperative management of lower airway injuries is a difficult clinical problem. Since few reviews present the management of this injury from an anaesthetic perspective, we undertook a literature review of this topic.

SOURCES

A computerized search of the National Library of Medicine database using tracheal or bronchial injury as key words produced 140 English language citations. An eight-year chart review outlining our experience in an urban Canadian setting is also presented.

FINDINGS

The most frequent findings in patients with injury to the lower airway are dyspnoea and surgical emphysema. Other findings include cough, haemoptysis, sucking neck or chest wounds, mediastinal emphysema or pneumothorax. Endoscopy with a fiberoptic scope is the technique of choice for diagnosis, airway management and as a preparatory step in planning of the surgical repair. An airway technique employing direct vision is preferable to blind attempts during tracheal intubation. The use of a double lumen endobronchial tube or selective endobronchial intubation may be needed to achieve adequate pulmonary ventilation. A number of prospective randomized clinical trials comparing conventional mechanical ventilation with high frequency jet ventilation in patients with acute lung injury have demonstrated no difference in effectiveness of ventilation or oxygenation.

CONCLUSIONS

Patients with lower airway injuries usually present when they are least expected and are a challenge to manage. The clinical presentation of a lower airway injury may be overt or subtle. Resuscitation and anaesthetic management are directed towards control of the airway, maintenance of adequate pulmonary ventilation and management of blood loss.

Surgical management of abdominal wall disruption after blunt trauma

Abdominal wall disruption following blunt trauma is a rare but challenging injury, both in the acute and convalescent phases. The present report describes the recent experience with this injury at a single adult trauma center. In a 22-month period, nine patients with traumatic abdominal wall disruption were managed. Flank and anteroinferior abdominal wall defects were most common. Associated injuries included 6 patients with a pelvic fracture and 4 patients with rectosigmoid injuries. Immediate primary repair of the defect was attempted in seven cases at the time of trauma laparotomy, but was difficult and often unsuccessful because of the related tissue destruction. Delayed abdominal wall repair was performed in patients with symptomatic disability (n = 5) and, if required, restoration of intestinal continuity was performed at a separate operation before abdominal wall repair. Delayed repair with autogenous tissue included the use of tensor fascia lata, rectus femoris muscle, rectus abdominis fascia, and latissimus dorsi muscle. Reconstruction with prosthetic mesh was required in two patients. One early and one late recurrence occurred, resulting in reoperation. In conclusion, traumatic abdominal wall disruption represents a complex challenge for both general and plastic surgeons. The key to successful surgical management seems to be a delayed staged repair with autogenous tissue when feasible.

A prospective study of emergent abdominal sonography after blunt trauma

In North America, the role of emergent abdominal sonography [ultrasonography (US)] after blunt trauma requires further definition. The purpose of this prospective study was to compare US to the gold standards, diagnostic peritoneal lavage (DPL), and computed tomography (CT), in a population of adults after blunt trauma. In 206 adults who required either CT or DPL to assess possible abdominal injury, US was performed, before DPL or CT, and was aimed at the detection of intraperitoneal fluid. The mean Injury Severity Score and Glasgow Coma Scale score were 24.0 and 11.9, respectively. One hundred thirty-seven patients (67%) had CT and 69 (33%) had DPL. The positive and negative predictive values of US for intraperitoneal fluid were 90% and 97%, respectively. The sensitivity, specificity, and accuracy of US for free fluid were 81%, 98%, and 96%, respectively. Of the six false-negative USs, only one required surgery. The US examinations required 2.6 +/- 1.4 min. Emergent abdominal sonography is an accurate, rapid test for the presence of intraperitoneal fluid in adult blunt trauma victims and in these patients may prove valuable as a screening test for abdominal injury.

Acute and long-term outcomes of extremely injured blunt trauma victims

Long-term outcomes after blunt trauma remain poorly defined. The purpose of this study was to document such outcomes in extremely injured adults (Injury Severity Score > or = 50). From April 1990 to June 1993, 76 patients (5% of all trauma victims) had an ISS > or = 50 at a single trauma center. Thirty-five (46%) survived to hospital discharge. The mean duration of hospital stay was longer for survivors than for nonsurvivors (92 days versus 16 days, p < 0.001). Of the 35 survivors, 26% were discharged directly home, 60% to a rehabilitation hospital, 8% to a chronic care facility, and 6% to an acute care hospital. After a mean follow-up of 27 months, 6% had died, 9% refused participation, and the remaining 30 patients (91% of long-term survivors) demonstrated significant residual disabilities in physical, emotional, and mental health status. We suggest that extremely injured patients comprise a small proportion of blunt trauma victims, consume substantial acute care hospital resources, often survive, and yet frequently have residual disability. A reduction in this long-term disability may represent the greatest challenge in modern trauma care.

Insertion of a transpyloric feeding tube during laparotomy in the critically injured: rationale and plea for routine use

Although clinical and experimental evidence favours early enteral feeding in the critically injured, provision of such enteral feeds can be difficult. Gastric feeds are often not tolerated and may lead to aspiration. An intolerance of gastric feeds leads to a cumulative energy and protein deficit and may result in the initiation of expensive parenteral nutrition (TPN). An alternative and under-utilized technique to ensure enteral access in trauma victims is the insertion of a transpyloric (nasojejunal) feeding tube during emergent laparotomy. We have employed this method of enteral access with success. In the following report, we describe this technique, provide an illustrative case with a cost comparison between nasojejunal feeds and TPN, present the rationale for such a mode of enteral access and outline the indications and contraindications. Enteral access by the intra-operative insertion of a transpyloric feeding tube allows immediate/early enteral feeding that is easy, safe, reliable and inexpensive.

What are the clinical determinants of early energy expenditure in critically injured adults?

The clinical determinants of energy expenditure in critically injured adults require definition. Among adult blunt trauma victims who required mechanical ventilation, the resting energy expenditure was calculated with the Harris-Benedict equation (HBEE) and the early (< or = 5 days postinjury) energy expenditure was measured by indirect calorimetry (MEE) (n = 115). The MEE was 2052 +/- 531 kcal/day and MEE/HBEE ("stress factor") was 1.24 +/- 0.2. The MEE was correlated with HBEE, age, height, weight, sex, temperature, and paralytic agents (p < 0.01). However, MEE did not correlate with ISS, admission GCS score, admission base deficit, initial systolic blood pressure, or the number of units of packed red blood cells transfused in the first 24 hours after injury (p = NS). Temperature and paralysis correlated with MEE/HBEE (p < 0.01). A regression model of MEE was developed with the clinical variables HBEE, temperature, and the presence or absence of paralytic agents (r2 = 0.62; p < 0.001): MEE (kcal/d) = 1.4(HBEE) + 71.4(temperature) + 274(paralytics; + = 1, - = 2) - 3485. In mechanically ventilated trauma victims, both the early energy expenditure and the stress factor are determined by host factors but are independent of the severity of the anatomic and physiologic insult. The degree of hypermetabolism observed in this population was less than previously reported.

Blunt diaphragmatic and thoracic aortic rupture: an emerging injury complex

Although both blunt diaphragmatic rupture (BDR) and thoracic aortic rupture (TAR) have been extensively discussed, the association of both injuries has been infrequently mentioned. The purpose of this study was to examine the current prevalence and clinical characteristics of combined BDR and TAR at an adult regional trauma unit. Among 3,886 trauma victims, 69 (1.8%) had a BDR and 44 (1.1%), a TAR. Seven patients (10% of all patients with a BDR) had both injuries. All 7 were victims of motor vehicle crashes and had a mean Injury Severity Score of 35. All TARs were just distal to the origin of the left subclavian artery. Five patients underwent repair of both injuries and survived, 1 patient had only the BDR repaired and survived, and 1 died during emergency thoracotomy, for a survival rate of 86%. Five patients had laparotomy and repair of the BDR in the presence of an unrepaired TAR. The TARs were repaired by the clamp-and-sew technique, three of them with primary repair and two with interposition tube grafts. Concomitant BDR and TAR appears to be an emerging injury complex with both diagnostic and therapeutic challenges. The presence of BDR demands a rigorous search for associated TAR.

Injuries missed during initial assessment of blunt trauma patients

OBJECTIVE

To determine the incidence and clinical significance of undiagnosed injuries in blunt trauma patients at our institution.

DESIGN

Retrospective analysis of blunt trauma admissions over a 1-year period. Missed injury (MI) was defined as any injury recorded after the initial 24 hours.

RESULTS

Of 432 patients studied, 59 (13.6%) had MI. Fractures were the most common MI. Thirty-five percent of MI were detected during repeated physical examination and 28% after patients were conscious and able to voice concerns.

CONCLUSION

Over 10% of all blunt trauma patients had undiagnosed injuries. Forty percent of the MI had clinical implications. The most effective method of diagnosis consists of repeated clinical assessments. Special attention should be focused on patients with severe anatomical injuries, obtunded or intubated.

Obesity

Although obesity and trauma both are common in the general population, discussion of the care of the critically injured obese patient has been relatively absent. Obesity is associated with significant clinical and occult multisystem disease. Because host factors are key determinants of post-traumatic course and outcome, obesity appears to be a marker of high risk. Obesity should be considered with age, pregnancy, cardiopulmonary disease, and substance abuse as a host factor that has significant post-traumatic ramifications. Only by employing a comprehensive, multidisciplinary approach to the critical care management of such patients will post-traumatic complications be prevented and treated effectively.

Management of the trauma victim with pre-existing endocrine disease

The clinical course of individuals after trauma largely is determined by their pretraumatic state. The endocrine system plays a major role in the response to injury, surgery, and sepsis, and endocrine dysfunction places the trauma victim at risk of greater morbidity and mortality. Further, chronic endocrine disease usually is accompanied by multiorgan dysfunction, which may compromise the physiologic reserve of the critically injured patient. Among patients with pre-existing endocrine disease, the severe stresses of multisystem trauma can lead to a further, often subtle, decompensation in endocrine function (Fig. 1). In the management of trauma victims with pre-existing endocrine disease, the role of the critical care specialist is three-fold--(1) to maintain a high index of suspicion for endocrine disease in all trauma victims, (2) to anticipate and prevent endocrine organ decompensation, and (3) to rapidly diagnose and institute therapy in those suspected of having endocrine disease.

Abbreviated laparotomy for damage control: a case report

During the initial operation on victims of multisystem trauma, life-threatening hypothermia, metabolic acidosis and coagulopathy occasionally develop. Without the immediate control of active bleeding and correction of these abnormalities, the intraoperative death rate is high. A patient with severe abdominal trauma was successfully managed with staged laparotomies. The patient's initial surgery was abbreviated to allow the aggressive correction of hypothermia and coagulopathy before definitive reconstruction of bowel injuries. Abbreviated laparotomy for damage control should be a part of the surgical armamentarium in the management of severe abdominal trauma.

Intrinsic pumping of mesenteric lymphatics is increased after hemorrhage in awake sheep

Lymphatic vessels have the ability to contract and transport liquid and protein from tissue spaces to the intravascular space. The purpose of this investigation was to test whether this lymph pump is stimulated following a fixed volume hemorrhage in awake sheep. To quantitate lymphatic pumping in vivo, a mesenteric lymphatic was isolated from all lymph input and provided with Krebs solution at a fixed transmural pressure. A branch of the mesenteric duct was cannulated to provide a measure of lymph flow rate. Each animal was either bled 25% of blood volume over 5 min or was observed. Systemic arterial blood pressure declined in all bled sheep (P < 0.05). Hemorrhage had no effect on lymph flow from mesenteric ducts. However, hemorrhage significantly enhanced lymphatic pumping, approximately 200% of control values 3 hr after hemorrhage (P < 0.01). Increased lymphatic pumping after hemorrhage may play an important role in blood volume and protein restitution.

Economic considerations

The costs to society of trauma care are huge. Multiple-injury patients in critical care units consume a vast percentage of the direct medical costs. This article examines the role that pre-existing diseases have on the length of stay in the critical care unit and the costs associated with this care.

A comparison of right and left blunt traumatic diaphragmatic rupture

Since right blunt traumatic diaphragmatic rupture (BTDR) is reported with increasing frequency, BTDR may be a disease in evolution. Data were collected on 59 left, 16 right, and five bilateral BTDRs at a level 1 trauma center. Patients with right BTDR had lower Glasgow Coma Scale (GCS) scores (p < 0.05), were more likely to be initially in hypovolemic shock, and were admitted directly from the field (p < 0.01). Left and right BTDRs were diagnosed from chest films in 37% and 0% of cases, respectively (p < 0.05). Diagnostic peritoneal lavage results were negative in 16% of left and left of 0% of right BTDRs. For right BTDRs, the liver was more likely to be injured (p < 0.001). The mortality rates were similar and ICU and hospital stays, complications, and duration of mechanical ventilation were similar for early survivors with right and left BTDRs. The clinical signs and symptoms, diagnosis, and surgical findings associated with right and left BTDR are different.

A comparison between a Canadian regional trauma unit and an American level I trauma center

Although there has been recent comparison of the Canadian and American health care systems, the issue of trauma has received little attention. Data were collected on all adult motor vehicle crash (MVC) victims admitted to the Sunnybrook Trauma Unit (CAN), Toronto, Canada, and the R Adams Cowley Shock Trauma Center (USA), Baltimore, Maryland from July 1986 through July 1990. Similar MVC victims at CAN and USA had equivalent mortality rates with similar discharge dispositions (p = NS), but patients at USA were twice as likely to be admitted to the ICU and had longer ICU stays (p < 0.01). The hospital-based cost for an average MVC patient at CAN was significantly less than for an average patient at USA and professional charges were at least five times greater at USA. This study provides some insight into the differences in trauma care between Canada and the United States.

A circulating protein that depolarizes cells increases after hemorrhage in dogs

Recent evidence suggests that a circulating factor or factors may mediate cell membrane depolarization after hemorrhage in rats. To test for the presence of a similar factor in dogs, conscious adult splenectomized dogs with chronic arterial cannulae were either (1) bled 30% of measured blood volume over 3 minutes (HEM, n = 8); (2) bled 30% of measured blood volume over 3 minutes and reinfused with the shed blood 10 minutes later (HEM + REINF, n = 6); or (3) observed without hemorrhage (CONTROL, n = 5). Treatments were applied in random order, 72 hours apart. Arterial blood was sampled at rest and for 1 hour. Depolarizing activity of the plasma was measured in an in vitro bioassay using resting dog RBCs and a membrane potential-sensitive oxonol dye (DIBAC). Fluorescence was measured by spectrofluorometry and the percentage of change from resting values was calculated. Fluorescence intensity increased after hemorrhage in the HEM and the HEM + REINF groups. Fluorescence intensity decreased to CONTROL values in the HEM + REINF group by 10 minutes after reinfusion of shed blood, but remained greater than CONTROL values in the HEM group. The magnitude of early cell membrane depolarization was approximately 20 mV. Similar depolarization was observed in cultured canine skeletal myocytes and pre-adipocytes. Changes in fluorescence intensity correlated with changes in mean arterial pressure at all times after hemorrhage except at 15 minutes (5 minutes after reinfusion in the HEM + REINF group). The depolarizing activity in dog plasma after hemorrhage shares several physical chemical properties with a similar substance identified in rats after hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)