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Biomedical subjects

Matthew B Klein

Publications and source records attributed to Matthew B Klein.

At least 19 recordsLinked to original sources
PubMed2006

An outcome analysis of patients transferred to a regional burn center: transfer status does not impact survival.

BACKGROUND: Optimal burn care is provided at specialized burn centers. Given the geographic location of these centers, many burn patients receive initial treatment at local emergency departments prior to transfer. The purpose of this study was to determine whether patients transferred from other facilities have worse outcomes than those admitted directly from the field. STUDY DESIGN: A retrospective cohort study was performed comparing the outcomes of patients admitted to our burn center directly from the field with patients requiring transfer from a preliminary care facility. The outcomes of interest were mortality, length of stay, length of stay/TBSA burned, number of operations and hospital charges. Poisson regression or Cox proportional hazards model was used to evaluate differences in outcomes after adjusting for potential confounders. RESULTS: From 2000 to 2003 a total of 1877 patients were admitted to our burn center and 953 (51%) were transferred from a preliminary care facility. No difference (p<0.05) was found in length of stay, number of operations, hospital charges and mortality between the two cohorts. CONCLUSIONS: This study demonstrates that patients transferred to a regional burn center from local hospitals have equivalent mortality, length of stay and hospital charges as those admitted directly from the field.

Adolescent↗
PubMed2006

Complex wound management utilizing an artificial dermal matrix.

The benefits of the Integra Dermal Regeneration Template in the management of extensive burn injuries have been well documented. Integra can reduce donor- and graft-site scarring and has been reported to be capable of vascularizing over small areas of exposed bone and tendon. Given these potential advantages, we have used Integra for a variety of other reconstruction applications. We performed a retrospective review of patients with complex wounds treated with Integra at our burn center. Integra was used in the management of a variety of wounds, including necrotizing fasciitis, extremity degloving injury, meningococcemia, Marjolin ulcer, postburn lip reconstruction, and fourth-degree burns with exposed bone or tendon. Engraftment rates of Integra and autograft were 98% +/- 4% and 97% +/- 4%, respectively. All areas of graft loss healed without need for regrafting. The benefits of Integra in the management of acute burn wounds can be extended to other traumatic and complex wounds.

Adolescent↗
PubMed2006

Correlation of clinical outcome of integra application with microbiologic and pathological biopsies.

BACKGROUND: Integra, a dermal replacement template consisting of bovine collagen, chondroitin-6-sulfate, and a silastic sheet is a postexcisional treatment for deep partial to full thickness burns where autograft is limited. This study correlates Integra histology and quantitative microbiology cultures with clinical outcomes after autografting. METHODS: Charts of 29 burn patients who underwent Integra treatment and neodermis biopsy at the time of ultra thin autografting were reviewed. We analyzed microbial contamination, inflammatory reaction, and autograft take. RESULTS: The mean burn size and age were 43% total body surface area and 39 years old, respectively. In quantitative neodermis cultures, 90% of samples had bacterial growth; nine samples (31%) had > 10(5) colony forming units per gram. The most common organism was Staphylococcus aureus (31%). Patients with quantitative bacterial counts >10(5) CFU/g received targeted systemic antibiotics. Integra take (83%) and autograft take (92%) were acceptable even in patients with high bacterial counts (78% Integra take; 86% autograft take). More than 50% of biopsies had dermal regeneration similar to normal dermis; foreign body reactions were unusual. Histologic evidence of inflammation, especially polymorphonuclear cells, was increased in biopsies with high bacterial counts. CONCLUSION: Integra and autograft take can be acceptable even with high bacterial counts if wounds are treated with appropriate targeted topical and systemic antibiotics in the presence of microbial contamination. Neodermis biopsies showed fibrous in-growth congruent with existing Integra fibers with minimal foreign body reaction. These data support Integra use as a safe and effective treatment modality in patients with major burns.

Administration, Topical↗
PubMed2006

Elevated orbital pressure: another untoward effect of massive resuscitation after burn injury.

BACKGROUND: Fluid resuscitation remains a fundamental component of early burn care management. However, recent studies suggest that excessive volumes of resuscitation are being administered. Overresuscitation results in negative sequelae including abdominal and extremity compartment syndromes. Elevated intraocular pressure (IOP) has been described as another potentially devastating effect of massive fluid resuscitation in trauma patients. The orbit, similar to the abdomen and extremity, is a compartment, limited to expansion from edema anteriorly by the eyelids and orbital septum, and posteriorly by the bony orbital walls. The purpose of this study was to review the incidence of elevated IOP in a series of patients with major burn injury. METHODS: We retrospectively reviewed the charts of 13 consecutive patients admitted to our burn center with burn sizes >25% total body surface area (TBSA). All patients underwent serial IOP measurements for the first 72 hours following admission. Medical records were reviewed for fluid resuscitation volume, IOP measurements, need for canthotomy, and results of canthotomy procedures. RESULTS: Five of 13 patients had IOP >30 mm Hg and required lateral canthotomy. Canthotomy immediately reduced IOP (p = 0.009). Patients who developed elevated IOP received a significantly larger fluid resuscitation (9.0 cc/kg/%TBSA versus 6.0 cc/kg/%TBSA, p = 0.02). Elevated IOP was significantly associated with delivery of larger fluid resuscitation volume (p = 0.027). CONCLUSIONS: Massive fluid resuscitation following burn injury can result in orbital compartment syndrome requiring lateral canthotomy. Early diagnosis and treatment of orbital compartment syndrome should be incorporated into the management of patients with major burn injury receiving large fluid resuscitation volume.

Adult↗
PubMed2006

Surgical management of acute necrotizing lung infections.

BACKGROUND: Surgical resection for acute necrotizing lung infections is not widely accepted due to unclear indications and high risk. OBJECTIVE: To review results of resection in the setting of acute necrotizing lung infections. METHODS: A retrospective review of patients who underwent parenchymal resection between January 1, 2000, and January 1, 2006, for management of necrotizing pneumonia or lung gangrene. RESULTS: Thirty-five patients underwent resection for lung necrosis. At the time of consultation, all patients presented with pulmonary sepsis, and also had the following: empyema (n = 17), hemoptysis (n = 5), air leak (n = 7), septic shock requiring pressors (n = 8) and inability to oxygenate adequately (n = 7). Twenty-four patients were ventilated preoperatively. Eleven patients had frank lobar gangrene, and the other patients had combinations of necrotizing pneumonia and abscesses. In 10 patients, preresection procedures were performed, including percutaneous drainage of an abscess (n = 4), thoracoscopic decortication (n = 4) and open decortication (n = 2). Procedures included pneumonectomy (n = 4), lobectomy (n = 18), segmentectomy (n = 2), wedge resection (n = 4) and debridement (n = 7). There were three (8.5%) postoperative deaths--two due to multiple organ failure and one due to anoxic brain injury. All patients not ventilated preoperatively were weaned from ventilatory support within three days. Of those ventilated preoperatively, three died, while four remained chronically ventilator dependent. CONCLUSIONS: Surgical resection for necrotizing lung infections is a reasonable option in patients with persistent sepsis who are failing medical therapy. Ventilated patients have a worse prognosis but can still be candidates for resection. Patients who are hemodynamically unstable appear to have better outcomes if they can be stabilized before resection.

Acute Disease↗
PubMed2005

Vascular mapping of the leg with multi-detector row CT angiography prior to free-flap transplantation.

PURPOSE: To retrospectively evaluate multi-detector row computed tomographic (CT) angiography in determining donor- and recipient-site arterial suitability for successful vascularized free-flap transplantation. MATERIALS AND METHODS: The institutional review board granted approval; informed consent was waived, and the study was HIPAA compliant. Lower extremities of 20 (12 male, eight female; mean age, 51 years; range, 10-84 years) patients undergoing vascularized free-flap procedures were examined at multi-detector row CT angiography. In five patients, legs were assessed as potential fibular free-flap donors for mandibular, maxillary, or radial reconstruction. In 15 patients, legs were assessed as recipient sites for free flaps. Vascular maps obtained with volume rendering, maximum intensity projections, and curved planar reformations were generated, and assessment was made in the depiction of calf vessels and presence of stenosis, occlusion, and anatomic anomaly. Findings of CT angiography, physical examination, and surgery were compared, where applicable, and successful CT-based prediction of the surgical intervention was assessed. Immediate and long-term (>70 days) viability of the graft was assessed in all patients. RESULTS: CT angiography depicted the entirety of all four major calf arteries in 29 of 32 legs scanned. In three legs, external-fixation hardware obscured some segments. There were no discrepancies between CT findings and those identified at the time of surgery. Arterial abnormalities, including stenosis, occlusion, and variant anatomy, were seen in 12 lower extremities in 10 patients. Only two were suspected on the basis of physical examination findings. In five of 20 patients, CT findings resulted in changes to the surgical plan. There was a 100% immediate viability of all grafts, which remained well vascularized between 70 days and 37 months after the procedure. CONCLUSION: Multi-detector row CT angiography provides a noninvasive means of preoperatively assessing lower extremity arteries for abnormalities, which could jeopardize graft viability or pedal arterial supply after free-flap procedures.

Aged↗
PubMed2005

Changes in VEGF and nitric oxide after deep dermal injury in the female, red Duroc pig-further similarities between female, Duroc scar and human hypertrophic scar.

Despite decades of research, our understanding of human hypertrophic scar is limited. A reliable animal model could significantly increase our understanding. We previously confirmed similarities between scarring in the female, red, Duroc pig and human hypertrophic scarring. The purpose of this study was to: (1) measure vascular endothelial growth factor (VEGF) and nitric oxide (NO) levels in wounds on the female Duroc; and (2) to compare the NO levels to those reported for human hypertrophic scar. Shallow and deep wounds were created on four female Durocs. VEGF levels were measured using ELISA and NO levels with the Griess reagent. VEGF and NO levels were increased in deep wounds at 10 days when compared to shallow wounds (p < 0.05). At 15 weeks, VEGF and NO levels had returned to the level of shallow wounds. At 21 weeks, VEGF and NO levels had declined below baseline levels in deep wounds and the NO levels were significantly lower (p < 0.01). We found that VEGF and NO exhibit two distinctly different temporal patterns in shallow and deep wounds on the female Durocs. Furthermore, NO is decreased in female, Duroc scar as it is in human, hypertrophic scar further validating the usefulness of the model.

Animals↗
PubMed2005

Management of facial burns with a collagen/glycosaminoglycan skin substitute-prospective experience with 12 consecutive patients with large, deep facial burns.

Management of deep facial burns remains one of the greatest challenges in burn care. We have developed a protocol over the past 20 years for management of facial burns that includes excision and coverage with thick autograft. However, the results were not perfect. Deformities of the eyelids, nose and mouth as well as the prominence of skin graft junctures demonstrated the need to explore novel approaches. Integra has been used with success in the management of burns of the trunk and extremities. The purpose of this study was to prospectively evaluate the aesthetic outcome of the use of Integra for deep facial burns. Twelve consecutive patients underwent excision of large, deep facial burns and placement of Integra. Integra provides excellent color and minimally visible skin graft junctures. The texture is good but not as supple as thick autograft. Integra is not well suited for use in the coverage of eyelid burns due to the need to wait 2 weeks for adequate vascularization. In summary, thick autograft remains the gold standard for deep facial burns. However, for patients with extensive burns and limited donor sites, Integra provides an acceptable alternative.

Adult↗
PubMed2005

Patterns of grease burn injury: development of a classification system.

Grease burns occur commonly in the home during food preparation. It has been our observation that grease burns follow a particular pattern of injury. The purpose of this study was to review our institutional experience in the management of these burns to develop a classification scheme. We performed a retrospective review of patients admitted to our burn center with grease burns. Subjects were identified through our database and their charts were reviewed with particular attention to burn distribution, TBSA and need for grafting. We excluded workplace burns and children under the age of six. A total of 249 patients who fit the above criteria were admitted with grease burns to our burn center from 1993 to 2003. The sequence of events leading to burn and its distribution followed a consistent pattern. The majority of patients (86%) had an isolated upper extremity burn or upper extremity burn in combination with a face, trunk or lower extremity burn. Forty percent of patients required at least one excision and grafting procedure. Grease burns associated with cooking at home follow predictable patterns of injury. Based on these patterns we proposed a classification system for domestic grease burns.

Accidental Falls↗
PubMed2004

Is supra-Baxter resuscitation in burn patients a new phenomenon?

Baxter described the use of 4 cm3/kg/%TBSA as a guideline for fluid resuscitation after burns. However, recent studies have shown that, at the present time, patients generally receive greater than the "Baxter" formula. Pruitt has called this phenomenon "fluid creep," and it has the potential for significant consequences including abdominal and extremity compartment syndromes and severe pulmonary insults. The purpose of this paper is to determine if this supra-Baxter resuscitation is a new phenomenon. We performed a retrospective chart review with two cohorts of patients. Group 1 consisted of 11 patients admitted between 1975 and 1978 to our burn center. Group 2 consisted of 11 patients admitted to our burn center in 2000 who were matched for age, sex, and percent total body surface area burned. Group 1 received 3.6 +/- 1.1 cm3/kg/% TBSA of fluid in the first 24 h. Group 2 received 8.0 +/- 2.5 cm3/kg/% TBSA, which is 100% more than the Baxter formula. There was no difference in the median age, weight, or 24-h urine output between the two groups. Our data demonstrate that the "fluid creep" phenomenon is relatively new.

Adolescent↗
PubMed2004

"Opioid creep" is real and may be the cause of "fluid creep".

Recent studies have shown that burn patients receive larger volumes of fluids than predicted by the Baxter formula and the reason for this is unclear. One potential reason is that increased analgesics are used which could blunt the response to fluid resuscitation. The purpose of this study was to compare the administration of opioid agonists in patients treated at a single burn center in the 1970s and in the year 2000. We performed a retrospective chart review comparing two matched cohorts. Group I consisted of 11 patients admitted between 1975 and 1978. Group II consisted of 11 patients admitted in 2000 matched for age, sex and %TBSA. Patients in Group II received a significantly higher mean opioid equivalent than those in Group I (26.5 +/- 12.3 versus 3.9 +/- 2.2 in the first 24h, P < 0.001). In addition, in Group II, a larger variety and combination of opioid agonists were used. This review demonstrates a significant increase from the 1970s to 2000 in the type, dose prescribed and dose delivered of opioid agonists. Along with "fluid creep", we have also increased our use of opioid agonists or "opioid creep". Higher doses of opioid agonists may have hemodynamic consequences, which may contribute to the increased fluid volumes.

Adolescent↗
PubMed2004

Flexor tendon wound healing in vitro: lactate up-regulation of TGF-beta expression and functional activity.

Flexor tendon wound healing in zone II is complicated by adhesions to the surrounding fibro-osseous sheath. These adhesions can significantly alter tendon gliding and ultimately hand function. Lactate and transforming growth factor-beta (TGF-beta) are two important mediators of wound healing that have been demonstrated to independently increase collagen production by cells of the tendon sheath, epitenon, and endotenon. This study examined the effects of lactate on TGF-beta peptide and receptor production by flexor tendon cells. Tendon sheath fibroblasts, epitenon tenocytes, and endotenon tenocytes were isolated from rabbit flexor tendons and cultured separately. Cell cultures were supplemented with 50 mM lactate, and the expression of three TGF-beta peptide isoforms (beta1, beta2, and beta3) and three receptor isoforms (R1, R2, and R3) was quantified with enzyme-linked immunosorbent assays. TGF-beta functional activity was also assessed with the addition of tendon cell conditioned media to mink lung epithelial cells transfected with a luciferase reporter gene expression construct responsive to TGF-beta. Supplementation of the cell culture medium with lactate significantly (p < 0.05) increased the expression of all TGF-beta peptide and receptor isoforms in all three cell lines. Tendon sheath fibroblasts exhibited the greatest increases in beta1 and beta2 peptide isoform expression (30 and 23 percent, respectively), whereas endotenon tenocytes demonstrated the greatest increase in beta3 peptide expression (32 percent). Epitenon tenocytes exhibited the greatest increases in receptor isoform R1 and R2 expression (17 and 19 percent, respectively). All three tendon cell types demonstrated significant (p < 0.05) increases in TGF-beta functional activity when exposed to lactate. Epitenon tenocytes demonstrated the greatest increase in activity (>4 times control values), whereas tendon sheath fibroblasts demonstrated the highest overall levels of total TGF-beta functional activity. Lactate significantly increased TGF-beta peptide (beta1, beta2, and beta3) expression, receptor (R1, R2, and R3) expression, and functional activity, suggesting a common pathway regulating tendon cell collagen production. Modulation of lactate and TGF-beta levels may provide a means of modulating the effects of TGF-beta on adhesion formation in flexor tendon wound healing.

Animals↗
PubMed2003

Protective effects of superoxide dismutase against ischemia-reperfusion injury: development and application of a transgenic animal model.

Reperfusion of ischemic tissues can be associated with structural and functional injury, which is referred to as ischemia-reperfusion injury. Superoxide dismutase is an endogenous free radical scavenger that converts toxic oxygen derived free radicals to hydrogen peroxide. With the development of gene cloning technology, the potential of manipulating cells to overexpress endogenous proteins has been realized. Transgenic mice capable of overexpressing superoxide dismutase, and knockout mice in which the gene responsible for its production has been deleted, were used as a model to examine the protective effects of superoxide dismutase against ischemia-reperfusion injury. Epigastric island flaps were elevated in wild-type (control), transgenic superoxide dismutase 1, and knockout superoxide dismutase 1 mice and subjected to ischemic intervals of 0, 3, 6, 9, or 12 hours. Five animals were studied at each time point in each study group. Flap viability was assessed on postoperative day 7. Baseline wild-type flap survival was 100 percent after 3 hours of ischemia and subsequent reperfusion; survival decreased to 21 percent after 9 hours of ischemia. Transgenic mice had significantly higher flap survival than wild-type animals after 6 hours of ischemia and subsequent reperfusion (97.0 versus 85.2 percent) and after 9 hours of ischemia (82 versus 21 percent, p < 0.01). In knockout mice, there was complete flap necrosis after as little as 3 hours of ischemia. This study confirms the protective effects of superoxide dismutase against ischemia-reperfusion injury. In addition, its deficiency results in a dramatic susceptibility to ischemic injury.

Abdominal Wall↗
PubMed2003

Early experience with computed tomographic angiography in microsurgical reconstruction.

Preoperative angiography is frequently used in the planning of microsurgical reconstruction. However, several potentially devastating complications can result from angiography, including arterial occlusion and pseudoaneurysm. Computed tomographic angiography is a relatively new technique that can provide detailed information about vascular anatomy as well as soft and bony tissue without the risks of traditional angiography. In addition, three-dimensional image reconstruction uniquely demonstrates anatomical relationships among blood vessels, bones, and soft tissue. Fourteen computed tomographic angiograms were obtained in 10 patients undergoing microsurgical reconstruction of the head and neck, lower extremity, or upper extremity. The average patient age was 46.9 years (range, 22 to 67 years). Charges related to the computed tomographic procedure were compared with those of conventional preoperative imaging for microsurgical repair. At our institution, the average computed tomographic angiogram charge was 1140 US dollars, whereas the average charge for traditional arteriography was 3900 US dollars. When compared with intraoperative evaluation, computed tomographic angiograms demonstrated clinically relevant surgical anatomy. No complications were noted for the radiographic procedure or after free flap reconstruction. Computed tomographic angiography provides high-resolution, three-dimensional arterial, venous, and soft-tissue imaging without the risks of traditional angiogram and at a lower cost.

Adult↗
PubMed2002

Flexor tendon healing in vitro: effects of TGF-beta on tendon cell collagen production.

Flexor tendon healing is complicated by adhesions to the surrounding sheath. Transforming growth factor beta (TGF-beta) is a cytokine with numerous activities related to wound healing. We examined the effects of TGF-beta-1, -2 and -3 on tendon cell proliferation and collagen production. Three separate cell lines--sheath fibroblasts, epitenon and endotenon tenocytes--were isolated from rabbit flexor tendons and cultured separately. Cell culture media was supplemented with 1 or 5 ng/mL of TGF-beta-1, -2, or -3. Cell number and collagen I and III production were measured and compared with unsupplemented control cultures. The addition of TGF-beta to cell culture media resulted in a decrease in cell number in all 3 lines that did not reach statistical significance. There was a significant increase (p <.05) in collagen I and III production with the addition of all 3 TGF-beta isoforms. Modulation of TGF-beta production may provide a mechanism to modulate adhesion formation clinically.

Animals↗