George O. Maish

Temporary abdominal closure techniques: a prospective randomized trial comparing polyglactin 910 mesh and vacuum-assisted closure.

OBJECTIVE The options for abdominal coverage after damage control laparotomy or abdominal compartment syndrome vary by institution, surgeon preference, and type of patient. Some advocate polyglactin mesh (MESH), while others favor vacuum-assisted closure (VAC). We performed a single institution prospective randomized trial comparing morbidity and mortality differences between MESH and VAC. METHODS Patients expected to survive and requiring open abdomen management were prospectively randomized to either MESH or VAC. After randomization, an enteral feeding tube was inserted and the closure device placed. VAC patients returned to the operating room every 3 days for a total of three changes at which time polyglactin mesh was placed if closure was not possible. The MESH group had twice daily assessments for the possibility of bedside mesh cinching and closure. Both groups underwent split thickness skin grafting when granulation tissue was evident, if delayed primary closure was not possible. RESULTS Fifty-one patients were randomized. Both cohorts were matched for Injury Severity Scale score, gender, blunt/penetrating/abdominal compartment syndrome and age. Three patients died within 7 days and were excluded from closure rate calculation. There were no differences between delayed primary fascial closure rates in the VAC (31%) or MESH (26%) groups. The fistula rate in the VAC group was 21% but not statistically different from the 5% rate for MESH. Intraabdominal rates were not statistically different. All VAC fistulas were related to feeding tubes and suture line areas; the MESH fistula followed a retroperitoneal colon leak remote from the mesh. CONCLUSIONS MESH and VAC are both useful methods for abdominal coverage, and are equally likely to produce delayed primary closure. The fistula rate for VAC is most likely due to continued bowel manipulation with VAC changes with a feeding tube in place-enteral feeds should be administered via nasojejunal tube. Neither method precludes secondary abdominal wall reconstruction.

The appropriate diagnostic threshold for ventilator-associated pneumonia using quatititative cultures

BACKGROUND The use of quantitative cultures of the bronchoalveolar lavage (BAL) effluent to distinguish between posttraumatic inflammatory response and ventilator-associated pneumonia (VAP) is becoming more common. However, the diagnostic threshold of either 10 or 10 colonies/mL remains debatable. Because mortality from VAP is related to treatment delay, some have chosen a lower diagnostic threshold (>10 colonies/mL). This may result in unnecessary antibiotic use with its sequelae: increased resistant organisms, antibiotic-related complications, and increased costs. The purpose of this study is to determine the optimal diagnostic threshold for VAP diagnosis using quantitative cultures of the BAL effluent. METHODS Data on patients with fiberoptic bronchoscopy with BAL are maintained in a prospectively collected database at our Level I trauma center. This database was reviewed for timing and frequency of BAL and the colony counts of each organism identified. Indication for bronchoscopy was clinical evidence of VAP. VAP was defined as >10 colonies/mL in the BAL effluent. A false-negative BAL was defined as any patient who had <10 colonies/mL and developed VAP with the same organism up to 7 days after the previous culture. RESULTS Over a 46-month period, 526 patients underwent 1,372 fiberoptic bronchoscopy procedures with BAL. Of these, 72% were male patients, 91% followed blunt injury, and mean age and Injury Severity Score were 43 years and 30, respectively. Overall mortality was 14%. There were 1,898 organisms identified (42% were gram-positive and 58% were gram-negative). VAP was diagnosed in 38% of BAL. Overall, there were 43 episodes in 38 patients defined as false-negative (3%). The false-negative rate was 9% in patients with 10 organisms. The most common false-negative organisms were Pseudomonas and Acinetobacter species. CONCLUSION The VAP diagnostic threshold for quantitative BAL in trauma patients should be >10 colonies/mL. One may consider a threshold of >10 colonies/mL in severely injured patients with Pseudomonas or Acinetobacter species.

A ten-year review of enterocutaneous fistulas after laparotomy for trauma.

BACKGROUND In the era of open abdomen management, the complication of enterocutaneous fistula (ECF) seems to be increasing in frequency. In nontrauma patients, reported mortality rates are 7% to 20%, and spontaneous closure rates are approximately 25%. This study is the largest series of ECFs reported exclusively caused by trauma and examines the characteristics unique to this population. METHODS Trauma patients with an ECF at a single regional trauma center over a 10-year period were reviewed. Parameters studied included fistula output, site, nutritional status, operative history, and fistula resolution (spontaneous vs. operative). RESULTS Approximately 2,224 patients received a trauma laparotomy and survived longer than 4 days. Of these, 43 patients (1.9%) had ECF. The rate of ECF in men was 2.22% and 0.74% in women. Patients with open abdomen had a higher ECF incidence (8% vs. 0.5%) and lower rate of spontaneous closure (37% vs. 45%). Spontaneous closure occurred in 31% with high-output fistulas, 13% with medium output, and 55% with low output. The mortality rate of ECF was 14% after an average stay of 59 days in the intensive care unit. CONCLUSION With damage-control laparotomies, the traumatic ECF rate is increasing and is a different entity than nontraumatic ECF. Although the two populations have similar mortality rates, the trauma cohort demonstrates higher spontaneous closure rates and a curiously higher rate of development in men. Fistula output was not predictive of spontaneous closure.

Mechanism of IL-1 induced inhibition of protein synthesis in skeletal muscle.

Chronic interleukin (IL)-1 administration is associated with negative nitrogen balance and the loss of lean body mass. To elucidate the molecular mechanism(s) by which IL-1 modulates protein metabolism in muscle, we investigated the effects of chronic (6 day) IL-1alpha infusion on protein synthesis in Individual muscles (gastrocnemius, soleus, heart) compared with saline-infused control rats. IL-1 significantly decreased muscle weight, protein content, and the rate of protein synthesis in gastrocnemius (fast-twitch muscle). IL-1 had no effect on these parameters in the heart, whereas only the rate of protein synthesis was reduced in soleus (slow-twitch muscle). The reduction in gastrocnemius protein synthesis was not the result of a decrease in total RNA content, but was associated with a diminished translational efficiency. The diminished translational efficiency correlated with a 40% reduction in the epsilon-subunit of eukaryotic initiation factor 2B (elF2Bepsilon) in gastrocnemius from IL-1 -treated animals. However, the content of the alpha-subunit of elF2 (elF2alpha) was unaffected. In contrast, the elF2alpha content in heart was increased by IL-1, although elF2Bepsilon levels were unchanged. Reductions in skeletal muscle protein synthesis were not associated with a concomitant reduction in circulating or tissue content of insulin-like growth factor I. In summary, the IL-1-induced decrease in gastrocnemius protein synthesis appears to be regulated at the level of RNA translation via a reduction in elF2Bepsilon. These findings support a regulatory role for IL-1 as a mediator of muscle protein synthesis and the alterations in body composition observed in catabolic states where this cytokine is overexpressed.

Disparate Response to Metoclopramide Therapy for Gastric Feeding Intolerance in Trauma Patients With and Without Traumatic Brain Injury

Patients with traumatic brain injury (TBI) have delayed gastric emptying and often require prokinetic drug therapy to improve enteral feeding tolerance. The authors hypothesized that metoclopramide was less efficacious for improving gastric feeding tolerance for trauma patients with TBI compared to trauma patients without TBI. A retrospective analysis was conducted of patients admitted to the trauma or neurosurgical intensive care unit who received gastric feeding from January 2006 to April 2008. Gastric feeding intolerance was defined by a gastric residual volume >200 mL or emesis with abdominal distension or discomfort. Patients with gastric feeding intolerance were given metoclopramide 10 mg intravenously every 6 hours, followed by a dose escalation to 20 mg, and then combination therapy with metoclopramide and erythromycin 250 mg intravenously every 6 hours if intolerance persisted. In total, 882 trauma patients (49% with TBI) were evaluated. TBI patients had a higher incidence of gastric feeding intolerance than those without TBI (18.6% vs 10.4%, P < or = .001). Efficacy rates for metoclopramide 10 mg, metoclopramide 20 mg, and metoclopramide-erythromycin were 55%, 62%, and 79%, respectively (P < or = .03). Metoclopramide failure occurred in 54% of patients with TBI compared to 35% of patients without TBI, respectively (P < or = .02), due to a greater prevalence of tachyphylaxis. Single-drug therapy with metoclopramide was less effective for TBI trauma patients compared to trauma patients without TBI. Combination therapy with erythromycin as first-line therapy for TBI trauma patients with gastric feeding intolerance is indicated if there are no contraindications or significant drug interactions.

Necessity of Repeat Head CT and ICU Monitoring in Patients With Minimal Brain Injury

BACKGROUND Recent publications have dismissed the need for routine repeat computed tomography (CT) scans in patients with minimal brain injury (MBI) (Glasgow Coma Scale score 13-15 with positive initial CT) unless physical examination changes. In an attempt to better allocate scarce resources, we hypothesized that not only was repeat head CT unnecessary but also routine intensive care unit (ICU) monitoring of these patients with MBI and stable examinations were unnecessary. METHODS All blunt injured patients admitted to a level I trauma center from January 2005 through December 2007 who met our criteria for MBI (Glasgow Coma Scale score 14-15 with positive initial CT) were reviewed. All patients had ICU monitoring and repeat CT done (at 12-24 hours) regardless of clinical examination. Patients with skull fractures, facial fractures needing urgent repair, those requiring immediate neurosurgical intervention and those with other injuries requiring ICU monitoring were excluded. Data including demographics, initial brain injury, follow-up CT scan results, changes in clinical examination, neurosurgical interventions, and ICU days were recorded. RESULTS Two hundred seven patients met criteria. Fifty-eight patients (28%) developed worsening findings on follow-up CT or examination. Eighteen required invasive neurosurgical intervention (6 intracranial pressure [ICP] monitors, 12 craniotomies) and 1 died (stroke). Those requiring ICP monitors had worsening intracranial hemorrhages (IPHs) with clinical examination changes or examination changes only, whereas those requiring craniotomy had worsening subarachnoid hemorrhage (2 patient), epidural hematoma (1 patient), and subdural hematoma (8 patients). Five of the subdural hematoma patients remained asymptomatic before craniotomy. ICU days were significantly increased in those patients with worsening CT findings who did not require neurosurgical intervention compared with those patients with unchanged or improved CT scans (5 days vs. 2.7 days, p < or = 0002). CONCLUSIONS Routine follow-up CT scans are beneficial in those patients with MBI and may lead to higher levels of medical management or neurosurgical intervention in patients with worsening CT findings. These patients should be kept in an ICU setting until head CT has stabilized. With these dissimilar results from previous studies, a prospectively randomized multicentered trial would be beneficial.

A reappraisal of nitrogen requirements for patients with critical illness and trauma.

BACKGROUND Studies regarding protein requirements for patients with critical illness are inconclusive owing to small sample size and population heterogeneity. The primary objectives of this study were to determine the amount of protein required to achieve nitrogen equilibrium or a positive nitrogen balance (NB, −4 g/d or better) and ascertain whether patients with traumatic brain injury (TBI) exhibit greater protein catabolism than those without TBI. METHODS Adult patients admitted to the trauma center, given specialized nutrition support, and had an NB determination within 5 days to 14 days after injury were evaluated. Patients with obesity, incomplete urine collection, kidney disease, corticosteroid or pentobarbital therapy, or an oral diet were excluded. RESULTS A total of 300 NB determinations from 249 patients were evaluated. Increasing the protein dosage generally resulted in improved NB; however, the data were highly variable. Of the patients who received a protein intake of 2 g/kg per day or greater, 54% achieved nitrogen equilibrium or positive NB (−4 g/d or better) in contrast to 38% and 29% of patients who received 1.5 g/kg per day to 1.99 g/kg per day and 1 g/kg per day to 1.49 g/kg per day, respectively (p < 0.001). There was no significant difference in NB between patients with and without TBI at similar protein intakes. CONCLUSION A higher protein intake was generally associated with an improved NB; yet, many patients remained having a negative NB. A protein dosage of 2 g/kg per day or greater was more successful in achieving nitrogen equilibrium than were lower-dosage intakes. Patients with TBI do not exhibit significantly greater protein catabolism than do patients without TBI. LEVEL OF EVIDENCE Prognostic study, level III.

Tumor necrosis factor mediates impaired wound healing in chronic abdominal sepsis.

BACKGROUND The role of systemic tumor necrosis factor (TNF) as a mediator of impaired wound healing in sepsis is unclear. The purpose of this study was to examine the effects of a specific TNF antagonist (TNFbp) on wound healing during chronic abdominal sepsis. METHODS Male Sprague-Dawley rats were divided into four groups: control, control + TNFbp, sepsis, and sepsis + TNFbp. Saline (1.0 mL) or TNFbp (1 mg/kg, 1.0 mL) was injected subcutaneously daily, polyvinylalcohol (PVA) sponge implants were placed in subcutaneous pockets, and sepsis was induced by creation of a chronic, intra-abdominal abscess. Sponge implants were removed on day 5 and examined histologically. Granulation tissue infiltration and quality (connective tissue, cellularity, vascularity) were scored on a scale from 1 to 4 in a blinded fashion. RESULTS Septic mortality (19 vs. 25%) was not influenced by TNFbp. Granulation tissue penetration and quality were decreased in septic animals. The administration of TNFbp significantly attenuated the effects of sepsis on granulation tissue histology, but not to control levels. CONCLUSIONS These studies provide evidence that TNF contributes to the impaired wound healing observed in this model of chronic abdominal sepsis.

The evolution of blunt splenic injury: resolution and progression.

BACKGROUND Nonoperative management of blunt splenic injury (BSI) has become the standard of care for hemodynamically stable patients. Successful nonoperative management raises two related questions: (1) what is the time course for splenic healing and (2) when may patients safely return to usual activities? There is little evidence to guide surgeon recommendations regarding return to full activities. Our hypothesis was that time to healing is related to severity of BSI. METHODS The trauma registry at a level I trauma center was queried for patients diagnosed with a BSI managed nonoperatively between 2002 and 2007. Follow-up abdominal computed tomography scans were reviewed with attention to progression to healing of BSI. Kaplan-Meier curves were compared for mild (American Association for the Surgery of Trauma grades I-II) and severe (grades III-V) BSI. RESULTS Six hundred thirty-seven patients (63.9% mild spleen injury and 36.1% severe injury) with a BSI were eligible for analysis. Fifty-one patients had documented healing as inpatients. Ninety-seven patients discharged with BSI had outpatient computed tomography scans. Nine had worsening of BSI as outpatients and two (1 mild and 1 severe) required intervention (2 splenectomies). Thirty-three outpatients were followed to complete healing. Mild injuries had faster mean time to healing compared with severe (12.5 vs. 37.2 days, p < 0.001). Most healing occurred within 2 months but approximately 20% of each group had not healed after 3 months. CONCLUSION Although mild BSIs heal faster than severe BSIs, nearly 10% of all the BSIs followed as outpatients worsened. Close observation of patients with BSI should continue until healing can be confirmed.

TNF-binding protein ameliorates inhibition of skeletal muscle protein synthesis during sepsis.

We examined the effects of TNF-binding protein (TNFBP) on regulatory mechanisms of muscle protein synthesis during sepsis in four groups of rats: Control; Control+TNFBP; Septic; and Septic+TNFBP. Saline (1. 0 ml) or TNFBP (1 mg/kg, 1.0 ml) was injected daily starting 4 h before the induction of sepsis. The effect of TNFBP on gastrocnemius weight, protein content, and the rate of protein synthesis was examined 5 days later. Sepsis reduced the rate of protein synthesis by 35% relative to controls by depressing translational efficiency. Decreases in protein synthesis were accompanied by similar reductions in protein content and muscle weight. Treatment of septic animals with TNFBP for 5 days prevented the sepsis-induced inhibition of protein synthesis and restored translational efficiency to control values. TNFBP treatment of Control rats for 5 days was without effect on muscle protein content or protein synthesis. We also assessed potential mechanisms regulating translational efficiency. The phosphorylation state of p70(S6) kinase was not altered by sepsis. Sepsis reduced the gastrocnemius content of eukaryotic initiation factor 2Bepsilon (eIF2Bepsilon), but not eIF2alpha. The decrease in eIF2Bepsilon content was prevented by treatment of septic rats with TNFBP. TNFBP ameliorates the sepsis-induced changes in protein metabolism in gastrocnemius, indicating a role for TNF in the septic process. The data suggest that TNF may impair muscle protein synthesis by reducing expression of specific initiation factors during sepsis.We examined the effects of TNF-binding protein (TNFBP) on regulatory mechanisms of muscle protein synthesis during sepsis in four groups of rats: Control; Control+TNFBP; Septic; and Septic+TNFBP. Saline (1.0 ml) or TNFBP (1 mg/kg, 1.0 ml) was injected daily starting 4 h before the induction of sepsis. The effect of TNFBP on gastrocnemius weight, protein content, and the rate of protein synthesis was examined 5 days later. Sepsis reduced the rate of protein synthesis by 35% relative to controls by depressing translational efficiency. Decreases in protein synthesis were accompanied by similar reductions in protein content and muscle weight. Treatment of septic animals with TNFBP for 5 days prevented the sepsis-induced inhibition of protein synthesis and restored translational efficiency to control values. TNFBP treatment of Control rats for 5 days was without effect on muscle protein content or protein synthesis. We also assessed potential mechanisms regulating translational efficiency. The phosphorylation state of p70S6 kinase was not altered by sepsis. Sepsis reduced the gastrocnemius content of eukaryotic initiation factor 2Bε (eIF2Bε), but not eIF2α. The decrease in eIF2Bε content was prevented by treatment of septic rats with TNFBP. TNFBP ameliorates the sepsis-induced changes in protein metabolism in gastrocnemius, indicating a role for TNF in the septic process. The data suggest that TNF may impair muscle protein synthesis by reducing expression of specific initiation factors during sepsis.