Multiinstitutional experience with the management of superior mesenteric artery injuries.

BACKGROUND: Superior mesenteric artery (SMA) injuries are rare and often lethal injuries incurring very high morbidity and mortality. The purposes of this study are to review a multiinstitutional experience with these injuries; to analyze Fullen's classification based on anatomic zone and ischemia grade for its predictive value; to correlate the American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) for abdominal vascular injury with mortality; and to identify independent risk factors predictive of mortality, describing current trends for the management of this injury in America. DESIGN: We performed a retrospective multiinstitutional study of patients sustaining SMA injuries involving 34 trauma centers in the US over 10 years. Outcomes variables, both continuous and dichotomous, were analyzed initially with univariate methods. For the subsequent multivariate analysis, stepwise logistic regression was used to identify a set of risk factors significantly associated with mortality. RESULTS: There were 250 patients enrolled, with a mean Revised Trauma Score (RTS) of 6.44 and a mean Injury Severity Score (ISS) of 25. Surgical management consisted of ligation in 175 of 244 patients (72%), primary [corrected] repair in 53 of 244 patients (22%), autogenous grafts were used in 10 of 244 (4%), and prosthetic grafts of PTFE in 6 of 244 patients (2%). Overall mortality was 97 of 250 patients (39%). Mortality versus Fullen's zones: zone I, 39 of 51 (76.5%); zone II, 15 of 34 (44.1%); zone III, 11 of 40 (27.5%); and zone IV, 25 of 108 (23.1%). Mortality versus Fullen's ischemia grade: grade 1, 22 of 34 (64.7%). Mortality versus AAST-OIS for abdominal vascular injury: grade I, 9 of 55 (16.4%); grade II, 13 of 51 (25.5%); grade III, 8 of 20 (40%); grade IV, 37 of 69 (53.6%); and grade V, 17 of 19 (89.5%). Logistic regression analysis identified as independent risk factors for mortality the following: transfusion of greater than 10 units of packed RBCs, intraoperative acidosis, dysrhythmias, injury to Fullen's zone I or II, and multisystem organ failure. CONCLUSION: SMA injuries are highly lethal. Fullen's anatomic zones, ischemia grade, and AAST-OIS abdominal vascular injuries correlate well with mortality. Injuries to Fullen's zones I and II, Fullen's maximal ischemia grade, and AAST-OIS injury grades IV and V, high-intraoperative transfusion requirements, and presence of acidosis and disrhythmias are significant predictors of mortality. All of these predictive factors for mortality must be taken into account in the surgical management of these injuries.

Candida infections in critically ill trauma patients: a retrospective case-control study.

HYPOTHESIS: We sought to determine whether the usual risk factors for fungal infections are applied to trauma patients. DESIGN: Case-control study. SETTING: American College of Surgeons Committee on Trauma-certified Level I trauma center in a tertiary care community hospital. PATIENTS: Screening of medical records of a consecutive sample of 459 patients aged 16 years or older admitted to an intensive care unit for 4 days or more from 1993 through 1996 identified 20 patients infected with Candida species. Two case controls for each were selected from the remaining patients using sex, age within 5 years, mechanism of injury, and best fit of first 4 Abbreviated Injury Scale scores; the Injury Severity Score and intensive care unit length of stay were also used if needed. INTERVENTIONS: None. RESULTS: Univariate analyses by t and chi2 tests showed significance (P<.05) for number of units of blood transfused in the first 24 hours after injury, gastrointestinal perforation, hemodialysis, and total parenteral nutrition. Steroids, fungal colonization, use of central venous catheters, Acute Physiology and Chronic Health Evaluation II score, mechanical ventilation for 3 days or more, and the number and duration of antibiotics were not significantly different. Logistic regression analysis showed that only total parenteral nutrition was an independent risk factor in this trauma population. CONCLUSION: Many of the classic risk factors for fungal infection in other populations are actually concomitants of injury severity and its requisite level of care in trauma patients. Hyperalimentation in persistently critically ill trauma patients significantly increases the risk of Candida infection.

Complications of primary repair of colon injury: literature review of 2,964 cases.

OBJECTIVE: To evaluate the safety and efficacy of primary repair of colon injuries. MATERIALS AND METHODS: A literature review was made of 35 publications containing 5,400 colon injuries in retrospective and prospective studies. RESULTS: There were 62 (2.4%) failures in 2,627 primary repairs based on surgeon discretion or absence of risk factors. In prospective series of 337 patients repaired without exclusionary criteria, there were 4 (1.2%) suture line failures (P = not significant). In prospective randomized trials without exclusionary criteria, 127 primary repairs had less morbidity compared with 109 diverted patients (P <0.02). The leak rate after resection and anastomosis (5.5%) is greater than after simple suture of perforation (1.4%; P <0.001). The 66 colon repair leaks were treated by conversion to colostomy or led to fistulae that usually healed spontaneously. A preponderance of failed repairs occurred in the setting of multiple injuries or comorbid conditions. CONCLUSIONS: Penetrating and blunt colon injuries in civilian practice are safely managed by primary repair, but colostomy may still be advised in selected cases.

'The broken halo sign': a fractured calcified ring as an unusual sign of traumatic rupture of the thoracic aorta.

Two elderly patients, involved in separate motor vehicle accidents, sustained blunt chest injury resulting in rupture of their thoracic aortas. The initial chest radiographs showed the presence of a calcified ring fractured in two places with lateral displacement of a calcified fragment by haematoma. This 'broken halo sign' is a radiographic sign not previously well described in the literature. The presence of a disrupted aortic ring in the elderly patient, associated with the appropriate mechanism of injury, should alert the clinician to the potential diagnosis of traumatic rupture of the thoracic aorta (TRTA).

Enteral versus parenteral nutrition after severe closed head injury.

We measured energy expenditure (MREE) and nitrogen excretion (UUN) in patients with severe head injury randomized to early parenteral (TPN, n = 21) or jejunal (ENT, n = 27) feeding with identical formulations. The MREE rose to 2400 +/- 531 kcal/day in both groups and remained at 135% +/- 26% to 146% +/- 42% of predicted energy expenditure over 4 weeks. Nitrogen excretion peaked the second week at 33.4 +/- 10 (TPN) and 31.2 +/- 7.5 (ENT) g N/day. Both routes were equally effective at meeting nutritional goals (1.2 x MREE, 2.5 g protein/kg/day intake, stabilized albumin and transferrin levels). Infections were equally frequent: 1.86 episodes/TPN patient versus 1.89 episodes/ENT patient. While patient charges were much greater for TPN, the hospital costs were similar for TPN and ENT support regimens. These findings show that patients with head injuries are hypermetabolic for weeks, that only 27% are capable of spontaneously eating nutritional requirements by discharge, and that either TPN or ENT support is equally effective when prescribed according to individual measurements of MREE and nitrogen excretion.

Nosocomial blood-borne infection secondary to intravascular devices.

A total of 143 patients with 159 episodes of intravascular device, blood-borne infection were studied. All infections were confirmed by the same organism being recovered from blood culture and by semiquantitative culture of the catheter tip. Sites of infection included the peripheral venous line (n = 72), central catheter (n = 49), arterial line (n = 18), subclavian dialysis catheter (n = 12), Swan-Ganz catheter (n = 4), Broviac catheter (n = 3), and transvenous pacemaker wires (n = 1). Staphylococcus aureus (n = 78) and Staphylococcus epidermidis (n = 33) predominated as pathogens. Excessive length of catheterization was implicated as directly responsible for this complication in patients with peripheral intravenous and arterial lines. Nosocomial staphylococcal bacteremia must be considered secondary to an indwelling intravascular device until proven otherwise. Appropriate therapy requires removal of the catheters, excision of the vein if suppuration or persistent bacteremia is identified, and specific antibiotic therapy.

Gastrointestinal perforation in infants.

We found that the mortality rate was no greater in patients with necrotizing enterocolitis complicated by perforation compared with the rate in those with other causes of perforation in similar weight classes. Iatrogenic injuries had a 50 percent mortality rate in all gestational age and birth weight categories and, therefore, great caution and surveillance are of utmost importance when using invasive monitoring and therapeutic modalities to prevent this cause of perforation. Term infants had a preponderance of mechanical causes of perforation which mainly occurred in the foregut and proximal midgut, whereas premature infants have a preponderance of asphyxial or ischemic events underlying perforations which mainly occurred in the ileocolic region and were often associated with necrotizing enterocolitis. Although neonatal intestinal perforation is a catastrophic event, the very premature infant weighing less than 1,000 g at birth is at significantly greatest risk. The discouraging 20 percent survival rate in the less than 1,000 g premature infants presents a challenge to the surgeon, since the overall survival rate was 59 percent and the term infants had a 78 percent survival rate. A substantial share of the mortality in the infants weighing less than 1,000 g at birth relates to the occurrence of intracerebral hemorrhage and bronchopulmonary dysplasia. Vigorous medical and surgical approaches can be used to salvage premature infants in all weight classes with gastrointestinal perforation.

The effects of gastrointestinal malignancy on whole body protein metabolism.

To study whether primary site or advancing stage of disease influenced whole body protein metabolism, [1-14C]leucine was used in five gastric and nine colorectal cancer patients and ten with benign disease. No differences were found by primary site or by comparing cancerous to benign patients. No differences were found between TNM stages 1, 2, or 3. Flux, synthesis and breakdown rates (2.30 +/- 0.29, 1.88 +/- 0.33, and 1.66 +/- 0.26 mmole leucine kg-1 day-1, respectively) were significantly greater in disseminated (stage 4) disease than in localized (stages 1-3) disease (1.71 +/- 0.32, 1.44 +/- 0.23, and 1.09 +/- 0.23 mmole leucine kg-1 day-1). Advanced cancer stage is marked by accelerated leucine metabolism, with flux and synthesis rates influenced primarily by feeding and secondarily by stage of disease. Protein breakdown rates correlated most closely to the stage of cancer. Cancer cachexia is the result of appetite suppression, decreased nutrient intake, and altered metabolism of endogenous substrates. Protein metabolism probably changes as a consequence, not a cause, of altered intake and energy metabolism in the tumor-bearing host.

A systematic study of host defense processes in badly injured patients.

A prospective study of factors predisposing to infection in badly injured patients has disclosed: the dominant roles of two specific parameters: monocyte antigen presenting capacity, and opsonic capacity of diluted serum; the potential value of further assessment of: the predictive value of plots of activated T-cells/total T-cells versus monocyte antigen presenting capacity, the apparent protective effect of the ability to sharply increase specific IgM in response to infection, and the apparent protective effect of cytomegalovirus (CMV) infection in the first 28 days after injury against major bacterial infection; the lack of value of analysis of other T- and B-cell subsets in such patients; and the need to clarify CMV and transfusion status with respect to interpretation of such data. The specific role of variable transfusion and of specific serum immunoglobulins will require further and more discriminating study.

The influence of surgical operations on components of the human immune system.

Surgical operations have been shown to cause a variety of immunological disturbances in man both in vivo and in vitro. With few exceptions the overall picture is one of a generalized state of immunodepression in the postoperative period. The implications of these observations are that host defences may be compromised by surgical procedures, thus providing a 'fertile soil' for bacterial invasion and tumour cell metastasis at the very time when risks from invading pathogens and viable tumour cells are maximal. We have studied the effects of surgical operations on the immune system in 35 patients with benign disease. Surgical procedures were classified as either minor (n = 15) or major (n = 20). A panel of monoclonal antibodies was used to identify peripheral blood lymphocyte subpopulations and analysis was performed using flow cytometry. Simultaneous estimations of plasma alpha-1 proteinase inhibitor (alpha-1-PI), alpha-2-macroglobulin (alpha-2-M), alpha-2-pregnancy-associated glycoprotein (alpha-2-PAG) and plasma suppressive activity (PSA) on stimulated allogeneic lymphocytes were performed before operation and on postoperative days 1, 3, 7, 17 and 21. Circulating numbers of all lymphocyte subpopulations fell significantly following surgery, except for B lymphocytes which did not change. The magnitude, and duration of the reduction in cell numbers and the subpopulation affected was significantly related to the degree of surgical trauma, and returned to pre-operative values by postoperative day 7. Changes in alpha-1-PI, alpha-2-M, alpha-2-PAG and PSA were also significantly related to the degree of surgical trauma, and these plasma changes persisted longer than the cellular disturbances. Surgical operations induce a reversible depression of cellular immunity which precedes plasma suppressive activity in its return to pre-operative levels. Immunostimulating agents such as interferon and the interleukins deserve evaluation as prophylactic agents pre-operatively.

Unifying concepts in treatment of esophageal leaks.

We treated 75 patients with esophageal trauma, perforation, or anastomotic leak. Several factors were shown to be associated with an increased mortality, including delayed treatment, presence of severe underlying esophageal disease, total parenteral nutrition catheter infection, the necessity for major extirpative procedures to treat the perforation, and the use of exclusion and diversion in the continuity procedure. The use of local muscle flaps to buttress suture line closure has led to excellent results in the 19 patients so treated. Delayed treatment of perforation or an anastomotic leak is a major problem, but the treatment protocol described herein has led to the survival of 12 of 16 patients treated. The use of primary muscle flap closure for extensive esophageal defects or delayed treatment of nonhealing leaks was evaluated in five patients. All five had healing of the defect, with one resultant esophageal stricture.

Value of the preoperative history as an indicator of hemostatic disorders.

Eighty-three general surgical patients completed the standardized bleeding history questionnaire, and screening tests of platelet counts, prothrombin times, partial thromboplastin times, and Ivy bleeding times were done on these patients. Fifty-two per cent had undergone previous operation; 25% described symptoms of potential hemostatic disorders and seven per cent had positive family histories. Laboratory results indicated abnormalities in five patients (6%). The bleeding history is an important part of the preoperative evaluation of a patient, but it can have serious false-negative results. This history should guide the selection of laboratory tests. Such testing can yield an unexpectedly high rate of abnormalities. When identified, these abnormalities require further investigation.

Technique of peritoneal dialysis cannulation in neonates.

A safe method for introducing a catheter for conducting peritoneal dialysis in neonates has been used successfully in 12 cannulations and has resulted in easy inflow and outflow of solutions without pericatheter leakage through the quite thin abdominal wall of the neonate. No significant complications have occurred.