Biomedical subjects

Addison K May

Publications and source records attributed to Addison K May.

11 recordsLinked to original sources

PubMed2006

Influence of broad-spectrum antibiotic prophylaxis on intracranial pressure monitor infections and subsequent infectious complications in head-injured patients.

BACKGROUND: The benefit of antibiotic prophylaxis for intracranial pressure (ICP) monitors remains controversial, and clinical practice varies widely. Whether any antibiotic coverage, particularly broad-spectrum coverage, reduces monitor-related infections remains unproved, and exposure to antibiotics may affect the susceptibility patterns of pathogens producing subsequent infectious complications. Despite the lack of data supporting its use, our level I trauma center had a long-standing ICP monitor prophylaxis protocol that provided broad-spectrum coverage that included ceftriaxone. In April 2002, a protocol change was instituted that substituted cefazolin for ceftriaxone as single-agent prophylaxis for ICP monitors. HYPOTHESIS: Broader-spectrum antibiotic prophylaxis does not reduce ICP monitor-related infections but is associated with acquisition of more drug-resistant infections than narrow-spectrum prophylaxis. METHODS: To evaluate the influence of broad- versus narrow-spectrum prophylaxis, a three year period encompassing each practice was selected. All injured patients with ICP monitors placed between January 1, 2001, and December 31, 2003 (n = 279), were identified using the Vanderbilt trauma database. Antibiotic prophylaxis for ICP monitors was determined using the hospital financial database to identify all antibiotics given to individual patients and subsequent chart review to identify those antibiotics given solely for ICP prophylaxis. A total of 119 patients received narrow-spectrum (either cefazolin or vancomycin; n = 100) or no (n = 19) prophylaxis, whereas 160 received broad-spectrum prophylaxis (ceftriaxone or ciprofloxacin). The two groups did not differ with respect to baseline demographics, type of ICP monitor, or duration of monitor placement. Infectious complications were determined by continuous infection surveillance utilizing standard U.S. Centers for Disease Control and Prevention National Nosocomial Infection Surveillance System (CDC-NNIS) definitions and maintained in a contemporary database. The influence of broad-spectrum antibiotic prophylaxis on both ICP monitor infections and subsequent infections outside the central nervous system (CNS) was determined. RESULTS: Nine patients (3.2%) developed CNS infections; two of 119 patients (1.7%) who received narrow-spectrum or no prophylaxis versus seven of 160 patients (4.4%) who received broad-spectrum prophylaxis (p = NS). Only the duration of monitor placement and Injury Severity Score were associated with the infection rate. In the total population, 185 infections occurred in 93 patients (33%). Infection rates did not differ between patients who received narrow-spectrum or no prophylaxis (32%) and those who received broad-spectrum prophylaxis (34%). However, patients who received broad-spectrum prophylaxis acquired gram-negative infections with significantly greater antibiotic resistance. CONCLUSIONS: Broad-spectrum antibiotic prophylaxis of ICP monitors does not reduce CNS infections, but is associated with a shift to resistant gram-negative pathogens in subsequent infectious complications. Thus, broad-spectrum antibiotic prophylaxis of ICP monitors should be eliminated or minimized unless data from randomized trials prove its utility.

Adult↗

PubMed2006

The open abdomen in trauma: do infectious complications affect primary abdominal closure?

OBJECTIVE: One of the primary goals of damage control surgery in the trauma patient is primary closure of the abdomen. We hypothesized that extra-abdominal infections, such as those complicating injuries to the thorax, diaphragm, long bones, or musculoskeletal system, would decrease the likelihood of primary abdominal closure and increase hospital resource utilization in patients requiring open abdominal management. METHODS: The trauma registry of the American College of Surgeons (TRACS) was reviewed retrospectively from 1995-2002 for open abdomen technique and damage control surgery. The outcome was primary fascial closure or delayed closure. Patients who died prior to closure were excluded. We evaluated infectious complications, including ventilator-associated pneumonia (VAP), blood stream infection (BSI), and surgical site infection (SSI). Other parameters studied were multiple rib fractures, long bone fractures, chest injuries, diaphragm injuries, empyema, and transfusion requirements. Hospital charges were obtained from the hospital administrative database. Univariate, multivariate, and regression analyses were performed to identify the effects of infectious complications on primary abdominal closure, length of stay, total hospital charges, and disposition. RESULTS: Three hundred forty-four patients required the open abdomen technique: 67% received damage control laparotomy and 33% decompression of abdominal compartment syndrome. Two hundred seventy-six patients (80%) went on to abdominal closure of some form and constituted the primary study group. Primary abdominal closure was achieved in 180 (65%) with a mean time to closure of 3.5 days. Ventilator-associated pneumonia, BSI, and SSI were associated with lack of primary closure (p < 0.05). Increased blood transfusions also were associated with failure of primary closure (p < 0.05). Ventilator-associated pneumonia and BSI were associated with significantly greater lengths of stay in the intensive care unit (ICU) (24.2 days vs. 12.6 days and 30.5 days vs. 17.9 days; both p < 0.0001) and significantly greater total hospital charges (232,080 US dollar vs. 142,893 US dollar; 247,440 US dollar vs. 160,940 US dollar; and 264,778 US dollar vs. 170,447 US dollar; all p < 0.001). CONCLUSION: Inability to achieve primary abdominal closure was associated with infectious complications (VAP, BSI, and SSI) and large transfusion requirements. Infectious complications also significantly increased ICU utilization and hospital charges. Death was associated with BSI, femur fractures, and large transfusion requirements, whereas infectious complications did not have a significant impact on discharge disposition.

Abdominal Injuries↗

PubMed2006

Activation of nuclear factor kappa B and severe hepatic necrosis may mediate systemic inflammation in choline-deficient/ethionine-supplemented diet-induced pancreatitis.

OBJECTIVES: We hypothesized that hepatic injury is associated with severe acute pancreatitis (SAP) and may result in lung injury through nuclear factor kappa B (NF-kappaB)-dependent inflammatory mediators. The study characterizes the timing and determines the involvement of selected cytokines and chemokines in the pathogenesis of hepatocellular injury associated with SAP. METHODS: The SAP was induced in C57BL/6 mice by feeding a choline-deficient/ethionine-supplemented diet. The mice were killed at 12-hour intervals for 96 hours. Terminal deoxynucleotidyl transferase-mediated nick-end labeling staining was used to determine the extent of hepatic apoptosis. The NF-kappaB activation in nuclear protein extracts from liver tissue was measured using a sensitive RelA enzyme-linked immunoadsorbent assay. Tumor necrosis factor alpha, interleukin 6, macrophage inflammatory protein (MIP) 2, and keratinocyte-derived chemokine (KC) levels in homogenates of liver and lung tissues were measured by enzyme-linked immunoadsorbent assay. The SAP-associated neutrophil lung inflammation was measured as tissue myeloperoxidase activity. RESULTS: The SAP and subsequent liver injury were confirmed by histological analysis and rises in plasma amylase and transaminase levels. Severe hepatocellular apoptosis was detected at 36 and 48 hours after the diet initiation by terminal deoxynucleotidyl transferase-mediated nick-end labeling staining (P < 0.05) and subsequently progressed to hepatic necrosis. Liver NF-kappaB activation was detected at 36 hours (P < 0.05) and followed by a sharp increase in hepatocellular levels of interleukin 6, MIP-2, and KC at 72 hours and thereafter (P < 0.05). Levels of MIP-2 and KC in lung tissue were also elevated at 72 hours (P < 0.05) and closely correlated with increased myeloperoxidase activity and increased inflammatory cell infiltrate in the lung. CONCLUSIONS: Choline-deficient/ethionine-supplemented diet-induced SAP is accompanied with hepatocellular apoptosis and eventual necrosis. This injury is associated with the hepatic NF-kappaB activation leading to the production of NF-kappaB-dependent cytokines and chemokines in the liver, which may mediate the lung injury.

Animals↗

PubMed2005

Creating an emergency general surgery service enhances the productivity of trauma surgeons, general surgeons and the hospital.

BACKGROUND: Several models that integrate trauma and emergency general surgery (EGS) have been proposed to provide a diverse and challenging operative practice for trauma surgeons and improve recruitment. In July 2002, our institution established a 24/7 EGS consult service, staffed primarily by critical care/trauma surgeons (CCTS). The objective of this report was to evaluate the impact of this new service on CCTS, general surgeons (GS) and the hospital. METHODS: All admissions to CCTS and GS from July 1, 2000 to June 30, 2003 were reviewed by querying hospital and physician databases for demographics, diagnoses, operative intervention(s), and resource utilization. Data were analyzed using nonparametric methods. RESULTS: [See ]. 9,405 admissions were identified, with GS and EGS admissions increasing over time. In July 2002, EGS became a separate service and captured 26% of GS admissions. Hospital-wide trauma admissions remained stable despite a slight decrease in trauma admissions to CCTS. A decrease in trauma operations by CCTS was offset by an increased EGS operative volume. EGS included "bread and butter" GS procedures including appendectomies and cholecystectomies and complex surgical procedures. EGS patients were often sicker with more than 50% requiring ICU admission compared with GS admissions of which only 10% required ICU care.(Table is included in full-text article.) CONCLUSIONS: Departmental restructuring to include an EGS service: 1) increased CCTS volume despite decreased CCTS trauma admissions and operations; 2) increased elective GS volume; 3) generated increased use of ICU and operating room resources; and 4) demonstrated that CCTS with broad operative GS backgrounds and critical care knowledge can effectively staff an EGS service.

Delivery of Health Care, Integrated↗

PubMed2005

The early work-up for isolated ligamentous injury of the cervical spine: does computed tomography scan have a role?

BACKGROUND: Helical computed tomography (HCT) scan is the preferred modality for diagnosing fractures of the cervical spine in blunt trauma. We hypothesize that HCT can be used as a screening tool for isolated ligamentous injury (LI) in blunt trauma. METHODS: A prospective, consecutive series study design was used to include patients that could not have their cervical spine cleared clinically. All patients underwent HCT (occiput-T1) and plain radiographs (PR) with five views of the cervical spine. Patients with clinical or radiographic abnormalities without fracture underwent cervical magnetic resonance imaging (MRI). Demographic and outcome data were collected. The attending radiologist's interpretation was used for clinical management. Three neuroradiologists in a blinded fashion re-reviewed the studies (HCT, PR, and MRI) of the MRI subgroup. RESULTS: One thousand five hundred seventy-seven patients met the study criteria. Two hundred seventy-eight had 416 cervical spine fractures. PR failed to identify 299 of 416 (72%) cervical spine fractures in 208 of 278 (74.8%) patients. Of the 1,299 (82%) patients who had no fracture, 85 (6.5%) required an MRI. The mean time from admission to MRI was 3 days for the LI subgroup. Of these, 21 of 85 (25%) had LI by MRI. Seven of 21 (33.3%) patients had an abnormal HCT versus 3 of 21 (14.3%) patients who had an abnormal PR. Four of 85 (4.7%) patients had spinal cord injury without radiographic abnormality. One (1.2%) patient required surgical stabilization of LI, as seen on all studies performed (PR, HCT, and MRI). Sensitivities for PR and HCT for LI were 16% and 32%, respectively. Negative predictive values for PR and HCT for LI were 74% and 78%, respectively. Measurements of interrater reliability for MRI, HCT, and PR had kappa values of 0.60, 0.14, and 0.41, respectively. CONCLUSION: HCT is the most sensitive, specific, and cost-effective modality for screening the cervical spine bony injuries, but it is not an effective modality for screening for cervical LI. MRI is clearly superior to HCT for LI. The indications for MRI include abnormalities on HCT, neurologic deficits, cervical pain or tenderness on examination, or the inability to clear the cervical spine in the obtunded patient. With the current state of the art technology, we have redefined the definition of spinal cord injury without radiographic abnormality to include spinal cord injuries without boney injuries or LI.

Adolescent↗

PubMed2005

Complications after 344 damage-control open celiotomies.

BACKGROUND: We reviewed our experience with the open abdomen and hypothesized that the known high wound complication rates were related to the timing and method of wound closure. METHODS: All trauma admissions from 1995 through 2002 requiring an open abdomen and temporary abdominal coverage were included. The study group was then classified by three wound closure methods used in survivors: 1) primary (primary fascial closure); 2) temporizing (skin only, spit thickness skin graft and/or absorbable mesh), and 3) prosthetic (fascial repair using nonabsorbable prosthetic mesh). RESULTS: In all, 344 patients required an open abdomen and temporary abdominal coverage either as part of a planned staged damage-control celiotomy (66%) or the development of the abdominal compartment syndrome (33%). Of these, 276 patients survived to wound closure. Sixty-nine of the 276 (25%) suffered wound complications (wound infection, abscess, and/or fistula). Thirty-four (12%) died after wound closure; seven of the deaths as a direct result of the wound complication. Complications increased significantly after 8 days (p < 0.0001) from the initial operative intervention to fascial closure. Primary fascial closure was achieved in 180 of 276 (65%) patients. Although there was no difference in the mean Injury Severity Score between the three groups, the primary group had significantly fewer mean transfusion requirements, shorter mean time to fascial closure, and a lower complication rate as compared with either the temporizing or prosthetic groups. The primary group thus incurred significantly less mean initial hospitalization charges. CONCLUSION: Morbidity associated with wound complications from the open abdomen remains high (25%). Morbidity is associated with the timing and method of wound closure and transfusion volume, but independent on injury severity. Also, delayed primary fascial closure before 8 days is associated with the best outcomes with the least charges.

Abdominal Injuries↗

PubMed2004

Bedside laparotomy for trauma: are there risks?

BACKGROUND: Critically ill trauma patients are often too unstable for safe transfer to the operating room. Damage control laparotomy patients frequently require early reoperation and have a reported mortality of 50-60%. As a result, many of these patients must undergo laparotomy in the intensive care unit. We hypothesized that patients undergoing bedside laparotomy (BSL) and managed with the abdomen left open would have an unacceptably high mortality or intra-abdominal complications. METHODS: We performed a retrospective chart review of our Trauma Registry. Of the 11,096 consecutive trauma admissions from March 1, 1996 to May 20, 2000, 75 patients underwent 95 BSL. Patients were stratified according to injury severity score (ISS), base deficit (BD), lactic acid (LA), total transfusion (TRBC) requirements, indication for BSL, mechanism of injury, infectious complications (intra-abdominal abscess (IAA), fistula), and length of hospital stay. RESULTS: Seventy-five patients underwent 95 BSL. Mean ISS was 50.6 +/- 18.9, mean BD was -11.9 (+/- 5), and the mean LA was 5 +/- 5 for the study group. The TRBC for the group was 43.7 +/- 42.6 units. Indications for the 95 BSL were (1) abdominal compartment syndrome (n = 47, 49.5%); (2) suspected intra-abdominal infection (n = 18, 19.0%); (3) washout/pack removal (n = 14, 14.7%); (4) washout with fascial closure (n = 12, 12.6%); and (5) other (n = 4, 4.2%). Twenty-nine of 75 patients (39.2%; ISS 52.3 +/- 18.8) died within 72 h of operation. Of the 46 remaining patients, an additional eight died 72 h or more after operation, for a late mortality rate of 17.4% and a total mortality rate of 49%. None of these deaths were attributable to either the operation or to post-operative IAA or fistula formation; all late deaths were secondary to multiple organ failure. Intra-abdominal abscesses developed in three of 46 patients (6.5%), each of whom had a TRBC of >100 units (mean, 160 units). Five of 46 patients (10.9%) developed enterocutaneous fistulae. None of these eight patients died. Thirty-eight of 75 patients (50.7%) survived to discharge, with a mean ISS of 40 (+/- 11.9). CONCLUSIONS: Despite the high acuity of the population undergoing BSL, 50.7% of patients survived. Moreover, during BSL, IAA and fistula formation occurred at low rates.

Abdominal Injuries↗

PubMed2004

Pulmonary MnSOD is nitrated following hepatic ischemia-reperfusion.

BACKGROUND: Ischemia-reperfusion (I/R) of remote organs is a common cause of lung injury. We observed that lung injury after partial hepatic I/R in mice coincides with the appearance of 3-nitrotyrosine (NT) in the lung tissue, a marker of peroxynitrite involvement and oxidant stress. Peroxynitrite can cause mitochondrial dysfunction by inactivation of manganese superoxide dismutase (MnSOD), the major antioxidant enzyme in mitochondria. Our aims were to examine whether pulmonary MnSOD is a target of nitration following hepatic I/R and whether nitrated MnSOD (N-MnSOD) correlates with acute lung injury. METHODS: Five 20-25-g male C57BL/6 mice underwent laparotomy, and atraumatic occlusion of the portal and arterial blood supply to the upper three lobes of the liver for 90 min. This warm ischemic period was followed by 4 h of reperfusion, and the animals were then euthanized. Lung injury was assessed by LDH and protein levels in bronchoalveolar lavage (BAL) fluid. Pulmonary MnSOD activity in pulmonary homogenates was measured by the cytochrome c reduction method. The presence of N-MnSOD was determined by immunoprecipitation (IP) and Western Blot analysis. Controls (N = 5) underwent sham operation. RESULTS: Elevated plasma transaminases confirmed hepatic injury. Lung injury was demonstrated by elevation in BAL protein and LDH levels (495.7 (48.4) versus 644.9 (37.3) [p < 0.05] and 56.5 (11.8) versus 345.2 (80) [p < 0.01], respectively). Immunoprecipitation and Western blot demonstrated N-MnSOD in the lung tissue of I/R animals but not controls. MnSOD activity decreased following I/R (8.1 (0.7) versus 10.8 (0.3) [p < 0.05]). CONCLUSIONS: Pulmonary MnSOD is both nitrated and inactivated following hepatic I/R and is associated with acute lung injury. These findings suggest that MnSOD incapacitance may contribute to I/R-induced lung injury and provide a therapeutic target in attenuating multisystem injury following hepatic I/R.

Animals↗

PubMed2004

Repair of giant abdominal hernias: does the type of prosthesis matter?

Closure of the abdominal wall after trauma or major surgery may be difficult due to visceral edema or fascial weakness; thus, the risk of developing a ventral hernia (VH) is high. Commonly, these hernias are repaired using a prosthetic mesh. Complications following mesh repair can develop. We hypothesize that the type of prosthetic material affects outcome. This is a retrospective chart review of patients admitted from 1996 to 2002 undergoing VH (> or = 20 x 10 cm) repair with prosthetic mesh. Data collected included age, sex, and race. Patients were stratified by prosthetic material as follows: Gore-Tex (GR), Marlex + Gore-Tex (MG), Marlex (MR), and Marlex + Vicryl (MV). For the purpose of clinical analysis, the groups were collapsed into subgroups: Gore-Tex exposure (GT) or non-Gore-Tex exposure (NG). Outcome measures were hernia recurrence (HR), wound infection (WI), and fistula formation (FF). Statistical analysis utilized chi2 test and Fisher's exact test. There were 55 VH repairs in 37 patients. The mean age was 43.9 (+/- 16.3), males out-numbered females 22 (59.5%) to 15 (40.5%). The majority of the patients were Caucasian (29; 78.4%). There were 30 trauma patients (81.1%), and 7 general surgery patients (18.9%). The HR for the study (n = 55) was 20 (36.4%), the WI was 17 (30.9%), and the FF was 3 (5.5%). GR group (6; 66.7%) had a significant higher wound IF rate than MR group (8; 26.7%) (Chi P = 0.02, Fisher P = 0.047). All other group comparisons (HR, WI, and FF) were N.S. The Gore-Tex versus non-Gore-Tex subgroup comparison results were as follows: GT (n = 18) had a WI 8 (44.4%), HR 6 (33.3%), and FF 0 (0%). NG (n = 37) had a WI 9 (24.3%), HR 14 (37.8%), and a FF 3 (8.1%). There was a trend toward a higher wound infection in the GT versus NG, but it did not reach statistical significance. We conclude that 1) the wound infection rate was higher in the Gore-Tex versus the Marlex group (Chi P = 0.02, Fisher P = 0.047). Wound infection in the presence of Gore-Tex usually mandates the removal of the mesh resulting in a hernia recurrence. 2) There was a trend toward a higher wound infection in the GT (44.4%) versus NG (24.3%), but it did not reach statistical significance.

Academic Medical Centers↗

PubMed2003

Endotoxin potentiates lung injury in cerulein-induced pancreatitis.

BACKGROUND: In this study we examine the effect of endotoxin (lipopolysaccharide) on lung injury in the setting of acute pancreatitis (AP). METHODS: Twelve hourly injections of cerulein (50 microg/kg/h) were used to induce pancreatitis in mice. Intraperitoneal lipopolysaccharide (LPS [6 mg/kg]) was administered 24 hours after the initial cerulein injection. Twenty-four hours after LPS injection, myeloperoxidase (MPO) activity, nuclear factor (NF)-kappaB activation, and tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and chemokines MIP-2 and KC levels were measured in pancreas, liver, and lung tissues. Four groups of mice were studied: cerulein-LPS, cerulein-saline, saline-LPS, and saline-saline treated mice. RESULTS: Elevated serum lipase confirmed pancreatitis in cerulein treated mice. Lung MPO activity was significantly increased in the cerulein-LPS group. NF-kappaB was activated in the liver but not in pancreas and lung tissue. Chemokines MIP-2 and KC were elevated in pancreatic tissue only. CONCLUSIONS: These findings suggest that gram-negative infections may be an important predisposition for the development of adult respiratory distress syndrome in the setting of AP and that hepatic NF-kappaB may mediate multisystem injury.

Animals↗

PubMed2003

Are five-view plain films of the cervical spine unreliable? A prospective evaluation in blunt trauma patients with altered mental status.

OBJECTIVES: Clearing the cervical spine in a time-sensitive fashion is difficult. We hypothesized that admission computed tomographic scan of the occiput to T1 (CTS) with multiplanar reformatted images will replace five-view (odontoid, anteroposterior, lateral, and oblique) plain films of the cervical spine (CSX) in the initial evaluation of blunt trauma patients with altered mental status. METHODS: Between January and July 2001, all patients aged 16 years or older with altered mental status undergoing both CTS and CSX were prospectively entered into the study group. Attending physician interpretation defined the presence of cervical spine injury. Unstable fractures were defined as requiring surgical or halo stabilization. RESULTS: One thousand six patients met study criteria. One hundred sixteen patients had 172 cervical spine injuries (CSIs) (fracture and subluxation). CSX missed 90 of 172 (52.3%) CSIs in 65 of 172 (56.0%) patients. Anatomically, CSX failed to identify 14 of 15 occipital fractures (93.3%), 17 of 36 (47.2%) C1-3 fractures, and 59 of 121 (48.8%) C4-T1 CSIs. CSX failed to identify 5 of 29 (17.2%) patients with unstable CSIs. CTS failed to diagnose 3 of 172 (1.7%) CSIs that were stable (spinous process fractures at C6-7). Two patients exhibited spinal cord injury without radiologic abnormality missed by both modalities. CTS had a sensitivity of 97.4%, a specificity of 100%, a prevalence of 11.5%, a positive predictive value of 100%, and a negative predictive value of 99.7%. CSX had a sensitivity of 44.0%, a specificity of 100%, a prevalence of 11.5%, a positive predictive value of 100%, and a negative predictive value of 93.2%. CONCLUSION: CTS outperformed five-view CSX in a group of patients with altered mental status or distracting injuries. Five-view CSX failed to diagnose 52.3% of cervical spine fractures identified by CTS. Five-view CSX failed to diagnose five patients with unstable cervical fractures and failed to identify 93.3% of patients with occipital condyle fractures.

Adult↗