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Biomedical subjects

Walter L Biffl

Publications and source records attributed to Walter L Biffl.

At least 37 records · Page 2Linked to original sources
PubMed2003

Clinically relevant hypertonicity prevents stored blood- and lipid-mediated delayed neutrophil apoptosis independent of p38 MAPK or caspase-3 activation.

BACKGROUND: Delayed apoptosis of primed neutrophils (PMNs) may facilitate PMN-mediated tissue injury leading to postinjury multiple organ failure. Aged (42-day-old) stored red blood cells (RBC42) delay PMN apoptosis through proinflammatory phospholipids such as platelet-activating factor (PAF) and lyso-phosphatidylcholine (LPC). Hypertonic saline (HTS) attenuates PMN cytotoxic functions. We hypothesized that clinically relevant HTS would provoke PMN apoptosis, as well as prevent stored blood- and lipid-mediated delayed PMN apoptosis through activation of p38 mitogen-activated protein kinase (MAPK) and caspase-3. METHODS: PMNs harvested from healthy volunteers were incubated (5% CO(2), 37 degrees C, 24 hr) with RBC42 plasma, PAF (20 microM), or LPC (4.5 microM), with or without the p38 MAPK inhibitor SB 203580, the caspase-3 inhibitor zDEVD-fmk (10 micromol/L) or the pan-caspase inhibitor zVAD-fmk (20 micromol/L). Duplicate samples were preincubated in HTS (Na [180 mM]). Apoptotic index (% PMNs undergoing apoptosis) was assessed morphologically. p38 MAPK activation was assessed by Western blotting. Caspase-3 activity was measured colorimetrically. RESULTS: PAF, LPC, and RBC42 plasma delayed apoptosis; HTS increased apoptosis compared with controls. HTS prevented PAF, LPC, and RBC42-delayed apoptosis. p38 MAPK was not activated by HTS; its inhibition had no effect on the actions of HTS. Caspase inhibition attenuated the ability of HTS to increase apoptosis, but it did not affect the ability of HTS to restore healthy PMN apoptosis in the presence of RBC42. CONCLUSION: HTS increases PMN apoptosis and prevents stored blood- and lipid-mediated delayed PMN apoptosis. HTS may activate caspase-3, but alternative signaling pathways appear to be involved in modulating the effects of lipids on PMN apoptosis.

Apoptosis↗
PubMed2003

Implementation of a tertiary trauma survey decreases missed injuries.

BACKGROUND: Missed injuries (MIs) adversely affect patient outcome and damage physician/institutional credibility. The primary and secondary surveys are designed to identify all of a patient's injuries and prioritize their management; however, MIs are prevalent in severely injured and multisystem trauma patients, especially when the patient's condition precludes completion of the secondary survey. We hypothesized that implementation of a routine tertiary trauma survey (TS) would reduce the incidence of MIs in a Level I trauma center. METHODS: In mid 1999, a TS form was created and TS documentation was mandated on all trauma intensive care unit (TICU) patients within 24 hours of admission. Patient data, including TS documentation and injury patterns, were concurrently recorded in an institutional trauma registry. Data were compared for patients admitted in 1997 to 1998 (PRE period) and 2000 to 2001 (POST period) using chi or Student's test. RESULTS: MIs decreased from 2.4% to 1.5% overall, and from 5.7% to 3.4% in TICU patients, after TS implementation. Patients with MIs were slightly older (49 vs. 45 years; > 0.05) and had higher Injury Severity Scores (21 vs. 10; < 0.05) than patients without MIs. Sixty percent of MI patients had brain injuries, 56% were admitted to the TICU, and 26% went directly from the emergency department to the operating room. The large majority of MIs in the POST period were detected in patients not undergoing timely TS. CONCLUSION: ICU patients-particularly brain injury victims and those undergoing emergent surgical procedures-appear to be at highest risk for MI. Implementation of a standardized TS decreased MIs by 36% in our Level I trauma center, and more timely TS would likely have further reduced MIs. A TS should be routine in trauma centers.

Adult↗
PubMed2003

Diagnosis of blunt cerebrovascular injuries.

PURPOSE OF REVIEW: Blunt cerebrovascular injuries (BCVI) are being increasingly recognized. The optimal criteria for screening, and the best diagnostic test, remain a matter of controversy. This review analyzes the available literature to propose management guidelines for the diagnosis of BCVI. RELEVANT FINDINGS: A number of centers are screening asymptomatic patients for BCVI. The criteria vary from center to center. The incidence of injuries diagnosed is proportional to the breadth of screening criteria. Noninvasive diagnostic modalities such as duplex ultrasonography, computed tomographic angiography, and magnetic resonance angiography have been proposed as screening tools. Although they are all capable of identifying many injuries, prospective comparisons reveal inaccuracies. SUMMARY: Screening for BCVI is appropriate. Institutions should adopt formal criteria, recognizing that more restrictive criteria are likely to miss injuries. Noninvasive modalities must be used with caution, because they have been found to be inferior to arteriography.

Angiography↗
PubMed2003

Cervical spine fracture patterns predictive of blunt vertebral artery injury.

BACKGROUND: Aggressive screening for blunt cerebrovascular injury (BCVI) has uncovered an astonishing incidence of vertebral artery injuries (VAIs) and associated stroke rate. Stroke incidence is reduced with early recognition and prompt anticoagulation. Because of the proximity of the cervical spine and vertebral arteries, we queried whether all patients with cervical spine fractures required arteriography to rule out VAI. METHODS: Four-vessel cerebrovascular angiography remains the standard screening test for patients at risk for BCVI. Patients undergoing angiographic screening for blunt cerebrovascular injuries have been prospectively followed at our regional trauma center since January 1990; however, in January 1996, we began aggressive screening based on injury patterns. RESULTS: Ninety-two patients with vertebral artery injuries were identified during the study period from January 1996 to June 2002. Two patients with vertebral injuries had minor cervical fractures, a C6 body fracture and a C7 spinous process/laminar fracture; both underwent diagnostic angiography for injury mechanism. Of the 21 patients without cervical spine fracture, angiographic screening for BCVI was performed for neurologic symptoms (11 patients), basilar skull fracture (6 patients), or severe facial fractures (4 patients). Cervical spine fracture was the sole indication for VAI in 69 patients. The fracture patterns were subluxations in 38 patients (55%) or extension of the fracture through the foramen transversarium in 18 patients (26%). The remaining injuries (18%) were located in the upper cervical spine: isolated C1 arch in eight patients and C2/3 body fractures in five patients. CONCLUSION: Blunt vertebral artery injury is associated with complex cervical spine fractures involving subluxation, extension into the foramen transversarium, or upper C1 to C3 fractures. Routine screening should incorporate these findings to maximize yield while limiting the use of invasive procedures.

Adult↗
PubMed2003

Isolated brain injury as a cause of hypotension in the blunt trauma patient.

BACKGROUND: Emerging evidence suggests that, contrary to standard teaching, isolated brain injury may be associated with hypotension. This study sought to determine the frequency of isolated brain injury-induced hypotension in blunt trauma victims. METHODS: Hypotensive adult trauma patients were categorized according to the cause of hypotension: hemorrhagic (hemoglobin < 11.0), neurogenic, isolated brain, or other. Their clinical data and outcomes were compared. RESULTS: The cause of hypotension was hemorrhagic in 113 (49%), isolated brain injury in 30 (13%), neurogenic in 14 (6%), and other causes in 24 (10%). Fifty (22%) were indeterminate. Hemorrhagic, isolated brain, and neurogenic groups were similar in age, Injury Severity Score, and systolic blood pressure. The Glasgow Coma Scale score of the isolated brain group was lower than in the hemorrhagic group (4.4 vs. 8.4, p < 0.05). Mortality was higher in the isolated brain group compared with the hemorrhagic group (80% vs. 50%, p < 0.05) and in the subgroup of hemorrhagic patients with versus without associated brain injury (57% vs. 39%, p < 0.05). CONCLUSION: Isolated brain injuries account for 13% of hypotensive events after blunt trauma and are associated with an increased mortality compared with hemorrhage-induced hypotension. In hypotensive brain-injured patients, hemorrhagic sources should be excluded rapidly, and the focus should be on resuscitation.

Adult↗
PubMed2002

Increased rate of infection associated with transfusion of old blood after severe injury.

HYPOTHESIS: Blood components undergo changes during storage that may affect the recipient, including the release of bioactive agents, with significant immune consequences. We hypothesized that transfusion of old blood increases infection risk in severely injured patients. DESIGN: Prospective cohort study. SETTING: Urban level I regional trauma center. PATIENTS: Sixty-one trauma patients with an Injury Severity Score greater than 15, age older than 15 years, and survival longer than 48 hours who were transfused with 6 to 20 U of red blood cells in the first 12 hours after injury were studied. By means of blood bank records, the age of each unit of blood was determined. INTERVENTION: Transfusion of allogeneic red blood cells. MAIN OUTCOME MEASUREMENTS: Major infectious complications. RESULTS: The early (<12 hours) transfusion requirement was 12 +/- 0.6 U, with a mean age 27 +/- 1 days. Major infections developed in 32 patients (52%). Age and Injury Severity Score were not significantly different between patients who developed infections and those who did not (age, 39 +/- 4 vs 36 +/- 3 years; Injury Severity Score, 33 +/- 1.5 vs 29 +/- 1.5). Transfusion of older blood was associated with subsequent infection; patients who developed infections received 11.7 +/- 1.0 and 9.9 +/- 1.0 U of red blood cells older than 14 and 21 days, respectively, compared with 8.7 +/- 0.8 and 6.7 +/- 0.08 in patients who did not develop infections (both P<.05, t test). Multivariate analysis confirmed age of blood as an independent risk factor for major infections. CONCLUSIONS: Transfusion of old blood is associated with increased infection after major injury. Other options, such as leukocyte-depleted blood or blood substitutes, may be more appropriate in the early resuscitation of trauma patients requiring transfusion.

Adult↗
PubMed2002

Evaluation of a new technique for bedside percutaneous tracheostomy.

BACKGROUND: Percutaneous tracheostomy as described by Ciaglia is accepted as a safe technique with minimal associated morbidity. Recent modification of the technique to a single-step dilator prompted us to evaluate this in the critically injured patient. METHODS: A comparison of patients undergoing percutaneous tracheostomy was performed. From May 1998 to May 1999, patients underwent surgery using the sequential multidilator technique (MDT), and from July 1999 to July 2000, patients underwent surgery using the single dilation technique (SDT). RESULTS: Ninety-three tracheostomies were performed, 49 MDT and 44 SDT. Time to tracheostomy and total ventilator days was similar between the groups. Three complications occurred. In the MDT group, 1 patient experienced delayed tracheal hemorrhage not requiring transfusion. In the SDT group, 1 patient had transient right lower lobe collapse, and another patient had unexplained extubation requiring emergent cricothyroidotomy. CONCLUSIONS: Percutaneous tracheostomy using the single-step Rhino dilator technique is technically easier than the currently accepted multidilator technique with equivalent complications.

Cohort Studies↗
PubMed2002

Predicting failure of outpatient laparoscopic cholecystectomy.

BACKGROUND: Outpatient laparoscopic cholecystectomy (LC) is safe and feasible, but factors related to the failure of outpatient surgery are poorly defined. We hypothesized that patients in whom same day discharge (SDD) is unlikely may be identified preoperatively. METHODS: Three hundred eighty-seven consecutive patients scheduled for elective LC were prospectively enrolled in an outpatient clinical pathway. RESULTS: In all, 269 (70%) patients successfully underwent outpatient LC. Factors related to failure of SDD were age, American Society of Anesthesiology (ASA) class, surgery start time, and duration of surgery. Body mass index, liver function tests, and ultrasound findings did not predict failure of SDD. Three factors were able to predict more than 50% failure of SDD: age more than 50 years, ASA class 3 or more, and surgery start time later than 1:00 PM. CONCLUSIONS: Outpatient LC is feasible in a large county hospital. These data may be used in scheduling cases and counseling patients.

Adult↗
PubMed2002

Treatment-related outcomes from blunt cerebrovascular injuries: importance of routine follow-up arteriography.

OBJECTIVE: To assess the impact of routine follow-up arteriography on the management and outcome of patients with acute blunt cerebrovascular injuries (BCVI). SUMMARY BACKGROUND DATA: During the past 5 years there has been increasing recognition of BCVI, but the management of these lesions remains controversial. The authors previously proposed a grading system for BCVI, with grade-specific management guidelines. The authors have noted that a significant number of injuries evolve within 7 to 10 days, warranting alterations in therapy. METHODS: A prospective database of a regional trauma center's experience with BCVI has been maintained since 1990. A policy of arteriographic screening for BCVI based on injury mechanism (e.g., cervical hyperextension) and injury patterns (e.g., cervical and facial fractures) was instituted in 1996. A grading system was devised to develop management protocols: I = intimal irregularity; II = dissection/flap/thrombus; III = pseudoaneurysm; IV = occlusion; V = transection. RESULTS: From June 1990 to October 2001, 171 patients (115 male, age 36 +/- 1 years) were diagnosed with BCVI. Mean injury severity score was 28 +/- 1; associated injuries included brain (57%), spine (44%), chest (43%), and face (34%). Mechanism was motor vehicle crash in 50%, fall in 11%, pedestrian struck in 11%, and other in 29%. One hundred fourteen patients had 157 carotid artery injuries (43 bilateral), and 79 patients had 97 vertebral artery injuries (18 bilateral). The breakdown of injury grades was 137 grade I, 52 grade II, 32 grade III, 25 grade IV, and 8 grade V. One hundred fourteen (73%) carotid and 65 (67%) vertebral arteries were restudied with arteriography 7 to 10 days after the injury. Eight-two percent of grade IV and 93% of grade III injuries were unchanged. However, grade I and II lesions changed frequently. Fifty-seven percent of grade I and 8% of grade II injuries healed, allowing cessation of therapy, whereas 8% of grade I and 43% of grade II lesions progressed to pseudoaneurysm formation, prompting interventional treatment. There was no significant difference in healing or in progression of injuries whether treated with heparin or antiplatelet therapy or untreated. However, heparin may improve the neurologic outcome in patients with ischemic deficits and may prevent stroke in asymptomatic patients. CONCLUSIONS: Routine follow-up arteriography is warranted in patients with grade I and II BCVIs because most of these patients (61% in this series) will require a change in management. A prospective randomized trial will be necessary to identify the optimal treatment of BCVI.

Adult↗
PubMed2002

The Outreach Trauma Program: a model for survival of the academic trauma center.

BACKGROUND: In the current health care climate, trauma centers face particular economic challenges. Statewide trauma systems provide a network for referral of critically injured patients to academic Level I trauma centers, but favorable reimbursement in states such as Colorado results in intense competition for patients. We hypothesized that a comprehensive Outreach Trauma Program would facilitate our mission as a key resource facility in our trauma system, and would increase referrals of critically injured patients to our center from outside our metropolitan area. METHODS: The Colorado statewide trauma system was formalized in 1995; our Outreach program-including providing visiting trauma call, continuing medical education lectures, 24-hour/7-day immediate consultation and transfers, and public relations/marketing-was fully implemented in 1997. We audited our trauma registry from January 1994 to July 2001 to determine the impact on patient volume and acuity as well as academic productivity. RESULTS: Annual overall trauma admissions have remained stable. Since 1997, high-acuity patients (i.e., Injury Severity Score > 15, intensive care unit admissions, those requiring surgery) have increased 27% to 51%, attributable largely to an approximately 300% increase in high-acuity Outreach patients. In 2000, Outreach patients constituted 8% of our total trauma admissions, but 21% of intensive care unit trauma admissions; notably, they accounted for 25% of our center's trauma charges. Meanwhile, our group's academic productivity has not suffered; in fact, we had 57 publications in 2000, compared with an average of 35 per year from 1993 through 1997. CONCLUSION: The Outreach Trauma Program has proven clinically, academically, and financially rewarding. Our program may serve as a model whereby academic trauma centers, through a demonstrated commitment to serving the clinical and educational needs of their referral base, can satisfy their mission while ensuring their survival.

Academic Medical Centers↗
PubMed2002

Lung-sparing techniques are associated with improved outcome compared with anatomic resection for severe lung injuries.

BACKGROUND: Pulmonary tractotomy was introduced in 1994 as a novel concept for lung salvage after penetrating wounds. Recently, tractotomy has been suggested to increase morbidity and, thus, its practice has been challenged. The purpose of this study was to compare the morbidity and mortality associated with nonanatomic and anatomic lung resection in the management of severe pulmonary injuries. METHODS: Using our trauma registry, patients admitted to an urban Level I trauma center during an 11-year period with thoracic injuries requiring thoracotomy and pulmonary operation were identified. A chart review was performed with attention to patient demographics, operative treatment, and outcome. Pulmonary operations performed were classified as either nonanatomic (wedge resection and tractotomy) or anatomic resection (lobectomy and pneumonectomy). Statistical analysis was performed using Student's test, Fisher's exact test, and logistic regression as appropriate. RESULTS: There were 34 men and 2 women, with a mean age of 29 +/- 2 years. Mechanism of injury was predominantly penetrating, with 26 (72%) gunshot wounds and 8 (22%) stab wounds. Intraoperative blood loss and early red blood cell transfusion requirement were lower in patients undergoing nonanatomic resection (3.85 L vs. 11.90 L and 17.4 U vs. 27.9 U, respectively; p < 0.05). Mortality was 4% in the nonanatomic resection group versus 77% in the anatomic resection group. CONCLUSION: Nonanatomic resection is associated with an improved morbidity and mortality compared with anatomic resection in the management of severe lung injuries. Although not a randomized study, these findings encourage the continued application of lung-sparing procedures when feasible.

Adult↗
PubMed2002

Noninvasive diagnosis of blunt cerebrovascular injuries: a preliminary report.

BACKGROUND: In light of their potential for devastating consequences, a liberalized screening approach for blunt cerebrovascular injuries (BCVI) is becoming increasingly accepted. The "gold standard" for diagnosis of BCVI is arteriography; however, noninvasive diagnostic alternatives offer clear advantages. Recent series have demonstrated the ability of computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) to identify BCVI, but have not compared their accuracy with arteriography. We hypothesized that CTA or MRA could reliably identify BCVI, obviating the need for arteriography. The purpose of this study was to determine the accuracy of CTA and MRA in identifying BCVI in asymptomatic patients. METHODS: Asymptomatic patients meeting criteria for BCVI screening underwent arteriography, according to our institutional standard. A subset of patients requiring computed tomographic scanning underwent CTA; a subset of patients requiring magnetic resonance imaging underwent MRA. All of the studies were interpreted by radiologists in a blinded manner. Data were analyzed for sensitivity and specificity. RESULTS: Forty-six patients underwent both CTA and arteriography. Of 23 with a normal CTA examination, 7 (30%) had BCVI on arteriography. Of 23 with an abnormal CTA examination, 8 (35%) had a normal arteriogram. The sensitivity, specificity, positive predictive value, and negative predictive value of CTA were 68%, 67%, 65%, and 70%, respectively. CTA missed 55% of grade I injuries, 14% of grade II injuries, and 13% of grade III injuries. Sixteen patients underwent both MRA and arteriography. One (11%) had a false-negative MRA result, and four (57%) had false-positive MRA results (75% sensitivity, 67% specificity, 43% positive predictive value, 89% negative predictive value). CONCLUSION: CTA and MRA can identify BCVI, but they miss grade I, II, and III injuries. Future technical modifications may improve their accuracy. A prospective multicenter trial is warranted to define the capabilities and limitations of these noninvasive modalities. In the interim, arteriography remains the gold standard for diagnosis, but if arteriography is not available, CTA or MRA should be used to screen for BCVI in patients at risk.

Angiography↗
PubMed2002

Hyperosmolarity abrogates neutrophil cytotoxicity provoked by post-shock mesenteric lymph.

Hypertonic saline (HTS) resuscitation inhibits acute lung injury in animal models of shock, but some argue this may simply represent more efficient fluid resuscitation. Inflammatory mediators within mesenteric lymph have been identified as a link between splanchnic hypoperfusion and acute respiratory distress syndrome (ARDS). We hypothesize that HTS resuscitation abrogates post-shock lymph-mediated neutrophil (PMN) priming and PMN-mediated human endothelial cell cytotoxicity. Mesenteric lymph was collected from rats (n = 5) before (control), during non-lethal hemorrhagic shock, defined as a mean arterial pressure (MAP) of 40 mmHg for 30 min, and after resuscitation (shed blood + 2 x lactated Ringers (LR) versus 7.5% NaCl, 4 cc/kg, over 5 min). Isolated human PMNs were primed with physiologic concentrations (5% v:v) of lymph either from animals resuscitated with LR or HTS and activated with either PMA or fMLP. In a separate set of experiments, human PMNs were primed with LR lymph after incubation with HTS (180 mM NaCl). The maximal rate of superoxide production was measured by reduction of cytochrome C. In addition, the effect of HTS pretreatment on PMN adherence to human pulmonary microvascular endothelial cells (HMVEC) and PMN-mediated cytotoxicity was determined after lymph-mediated PMN priming. PHSML primed isolated PMNs above buffer controls and pre-shock lymph in a normotonic environment; HTS resuscitation abrogated this effect. HTS preincubation of isolated PMNs inhibited PHSML-induced PMN priming, adherence to HMVECs, and PMN-mediated HMVEC cytotoxicity. Hypertonic resuscitation (HTS) abrogates PHSML pniming of the PMN and PMN-mediated HMVEC cytotoxicity. Furthermore, incubation of PMNs in clinically relevant HTS (180 mM NaCl) prevents PHSML PMN priming and PMN:HMVEC interactions. These studies suggest inhibition of PMN signal transduction is a mechanism whereby HTS resuscitation abrogates acute lung injury.

Animals↗
PubMedDate not supplied

Nutrition support of the trauma patient.

Hypercatabolism after trauma may lead to acute protein malnutrition, ultimately resulting in multiple organ failure. Nutrition support may prevent this sequence. This review addresses the need for early nutrition support, the preferred route of substrate delivery, and the potential advantages of "immune-enhancing" diets.

Energy Metabolism↗