From past paradigms to future frontiers: unique care delivery models to facilitate nursing work and quality outcomes

As healthcare processes were reengineered in response to managed care, traditional care delivery models were abandoned, resulting in nursing staff dissatisfaction, increased healthcare error, and eroding clinical outcomes. An aging patient population, chronicity of illness, the proliferation of new medical information and technology, severity of illness, and the focus of acute care to "stabilization and transition" necessitate the creation of systems that address changes in nursing work expectations while maximizing available resources. By evaluating unit-specific structure and process criteria and allocation of provider roles, unique, setting-specific care delivery models can be created to facilitate direct and nondirect patient care functions, resulting in improved financial and clinical outcomes.     

Age-associated sex differences in response to food deprivation in two animal tests of anxiety

The effects of mild food deprivation (7 days of food restricted to once daily feeding to maintain body weights at 85% of free-feeding weights) were examined in adult male and female and adolescent female rats tested in the elevated plus maze and social interaction tests of anxiety. In adult male rats, food deprivation appeared to have an anxiolytic effect in the plus-maze as it significantly increased the percentage of entries onto open arms and the percentage of time spent on the open arms, without changing the number of closed arm entries. There were no effects of food deprivation in adult females, although in adolescent females food deprivation significantly increased the percentage of open arm entries rats. Adolescent female rats have female brains, but do not have circulating gonadal hormones and thus these results suggest that circulating female gonadal hormones are able to suppress some of the effects of mild food deprivation in the plus-maze. In the social interaction test, there were no effects of food deprivation in any group on the time spent in social interaction. There were opposite effects on locomotor activity in the adult male and female rats, with deprivation increasing activity in males and decreasing it in females. There were no effects of food deprivation on locomotor activity in the adolescent females, suggesting that circulating gonadal hormones were responsible for the bidirectional effects in the adult rats. In both tests there were age-associated differences in the female rats, with the adolescent females being less anxious (higher percentage of open arm entries and increased social interaction) than the adults.     

Preoperative prediction of the risk of pulmonary complications after esophagectomy for cancer

OBJECTIVES: Pulmonary complication is a frequent morbid event after esophagectomy for cancer. Its prediction may help select patients for preoperative rehabilitation. METHODS: We performed a retrospective review of 292 patients (231 men and 61 women; mean age, 60.1 years) who underwent esophagectomy for cancer between 1980 and 2000. Data were analyzed to identify factors associated with the development of pulmonary complications (reintubation for isolated respiratory failure and pneumonia). A scoring system was developed, and its ability to predict complications was assessed. RESULTS: Resection was performed for squamous cancer (n = 100), adenocarcinoma (n = 186), and other histologic types (n = 6) in patients with stages 0 or I (n = 53), II (n = 94), III (n = 114), and IV (n = 23) disease. Pulmonary complications, which developed in 78 (27%) patients, were associated with a 4.5-fold increase in operative mortality (7%-32%). Multivariable analysis identified independent predictors of pulmonary complications to be patient age (odds ratio [OR], 1.31; 95% confidence interval [CI], 0.99-1.74; P =.059), percentage forced expiratory volume in 1 second (OR, 1.21; 95% CI, 1.07-1.38; P =.003), and possibly performance status (OR, 1.48; 95% CI, 0.88-2.50; P =.14). A scoring system using these 3 covariates was developed, which predicted incremental risk of pulmonary complications (P =.013). The incremental risks of cardiovascular and overall cardiopulmonary complications were also predicted with this scoring system (P <.01 for each). CONCLUSIONS: A scoring system using patient age, spirometry, and performance status helps predict the likelihood of pulmonary and cardiovascular complications after esophagectomy and can help select patients who may benefit from preoperative cardiopulmonary rehabilitation.     

Longitudinal impedance is independent of outflow resistance

BACKGROUND: Many investigators have measured outflow resistance (R) following peripheral bypass procedures, but correlations with graft patency have been weak. This is because the primary determinants of graft patency are the size and quality of the conduit, not its outflow bed. Efforts at separating conduit resistance from outflow resistance have been unsuccessful. Recently, the concept of longitudinal impedance ( integral Z(L)) has been suggested as a measure of conduit resistance independent of outflow resistance. The purpose of this in vitro experiment was to test the hypothesis that integral Z(L) is independent of R within physiologically relevant ranges. METHODS: Rigid polyethylene tubing of known internal diameter and length (4.3 mm, 375 cm) was perfused with a glycerin/saline mixture mimicking the viscosity of blood (4.1 cp), utilizing a variable pulsatile pump and Windkessel, with outflow into multiply branched tubes of decreasing diameter simulating the hemodynamic conditions of arterial bypass. Flow and pressure were measured using ultrasonic transit time and catheter transduction, respectively, and waveforms digitized at 200 Hz. Flow was varied while maintaining "systemic" pressure and resistance. After Fourier transformation, integral Z(L) was calculated as deltaP/Q at each harmonic and integrated over 4 Hz. RESULTS: integral Z(L) calculations were remarkably reproducible within the same day with a coefficient of variation (CV) = 4.0% (at 100 dyne. s/cm(5); n = 4) or over 4 successive days (CV = 4.3%). Furthermore, integral Z(L) was largely independent of R over the physiologic range tested, with integral Z(L) remaining relatively constant as R was increased sixfold. CONCLUSION: integral Z(L) is a consistent and reproducible measure of conduit resistance independent of R over a wide physiologic range. It may be useful for measuring the adequacy of bypass graft conduits.     

Selectins influence thrombosis in a mouse model of experimental deep venous thrombosis

BACKGROUND: This study characterizes venous thrombosis in the mouse and examines the important role that the adhesion molecules P-selectin and E-selectin and the anti-inflammatory cytokine interleukin-10 (IL-10) play in the thrombotic process. MATERIALS AND METHODS: C57BL/6 (wild-type) mice in a natural history protocol (Phase I) and gene-targeted (KO) mice for P-selectin, E-selectin, P/E-selectin, and IL-10 in a follow-up protocol (Phase II) were studied. Inferior vena caval thrombosis was produced by ligation just below the renal veins, and mice were sacrificed and evaluated at various time points up to 12 days later. RESULTS: Phase I: A significant increase in neutrophils on day 2 and in monocytes on day 6 postthrombosis was found in ligated vs sham animals. An associated significant increase in vein wall P-selectin mRNA (6 h, day 2) and an increase in protein (6 h through day 6) were found, while E-selectin mRNA was significantly increased (day 2 through day 6), with a smaller increase in E-selectin protein. IL-10 mRNA increased significantly later (day 2 through day 9), with the values increasing progressively. A positive correlation existed (r = 0.77) between neutrophils and thrombosis at day 2. PHASE II: The E-selectin and P/E-selectin double-KO mice showed the least thrombus at day 2 vs wild-type clotted mice, P < 0.01. Additionally, P/E-KO mice demonstrated the lowest inflammatory cell extravasation into the vein wall at day 2. CONCLUSIONS: This study demonstrates an acute to chronic inflammatory response in the vein wall associated with venous thrombosis. Inhibition of selectins decreased thrombus formation.     

Lumbar fractures in adult blunt trauma: axial and single-slice helical abdominal and pelvic computed tomographic scans versus portable plain films

BACKGROUND: Our hypothesis was that abdominal and pelvic computed tomographic (AP-CT) scans are equivalent to portable two-view plain films in detecting lumbar spine fractures in adults. Since many trauma patients often undergo AP-CT scanning to evaluate for possible intra-abdominal injuries, using the AP-CT scan to screen for lumbar fractures could make the trauma evaluation process more efficient. METHODS: The institutional trauma registry at a Level I trauma center was used to identify all blunt lumbar fractures during a 6-year period. Medical records were reviewed. RESULTS: A total of 7,216 adult blunt trauma patients were evaluated, and 115 patients were identified as having a lumbar fracture, for an incidence rate of 1.6%. Missed fracture rates were high for both AP-CT scans (23.2%, 13 of 56) and portable two-view films (12.7%, 14 of 110, = 0.08). Fifty-two patients had both AP-CT scans and plain films. In this group, AP-CT scans missed 23.1% (12 of 52) of the lumbar fractures and plain films missed 15.4% (8 of 52). However, the combination of the two diagnostic methods did not miss any fractures (0 of 52). The missed fractures required surgery or brace in 50% (7 of 14) patients who had fractures missed by plain films and 46% (6 of 13) patients whose fractures were missed by AP-CT scanning. CONCLUSION: Both AP-CT scans and plain films failed to diagnose significant lumbar fractures that required therapy. When screening for lumbar fractures, obtaining both AP-CT scans and portable two-view plain films may decrease missed lumbar fractures in blunt adult trauma.     

Recombinant human neutral endopeptidase ameliorates pancreatic elastase-induced lung injury

BACKGROUND: Genetic deletion of neutral endopeptidase (NEP), a cell-surface metalloprotease that degrades proinflammatory peptides, exacerbates lung injury induced by pancreatic elastase in a model of pancreatitis-associated lung injury. We tested 3 hypotheses: (1) genetic deletion of NEP prolongs lung recovery after elastase injections; (2) elastase-mediated lung injury is associated with down-regulation of NEP; and (3) pretreatment of NEP (-/-) and (+/+) animals with recombinant human NEP (rhNEP) reduces pulmonary damage in this model. METHODS: NEP (+/+) or (-/-) mice were injected with pancreatic elastase (0.085 U/g/dose intraperitoneally) or saline carrier at t = 0 hours and t = 1 hour. Some mice were pretreated with rhNEP (3 mg/kg intraperitoneally). Serum elastase, lung histologic score, myeloperoxidase, and NEP activities were measured at 4, 8, or 12 hours. RESULTS: NEP (-/-) mice had worse pulmonary inflammation at 4 and 8 hours versus (+/+) mice. Lung NEP activity was similar in elastase-treated and control (+/+) animals. Pretreatment with rhNEP reduced myeloperoxidase and improved histology at 4 hours in NEP (-/-) and (+/+) mice. CONCLUSIONS: Pancreatic elastase induces lung injury that is worse and prolonged in NEP (-/-) mice. Pretreatment with rhNEP ameliorates this injury. Thus, upregulation of NEP is a potential therapeutic approach for pancreatitis-associated lung injury.     

Humorally mediated posttransplantation septal capillary injury syndrome as a common form of pulmonary allograft rejection: a hypothesis

BACKGROUND: Cellular immunity is the reputed mechanism of lung allograft failure. Humoral immunity is not a commonly recognized pathway. MATERIAL AND METHODS: We describe 22 patients who developed a posttransplantation septal capillary injury syndrome in the absence of panel-reactive antibodies. Factor VIII levels served as an index of microvascular injury. Routine light microscopic studies were performed in a total of 73 biopsies; 54 biopsy specimens were analyzed for deposition of C1q, C4d, C5b-9, and immunoglobulin (IgG, IgM, and IgA). Indirect immunofluorescent testing to assess for antiendothelial cell antibodies was performed using patient serum and human pulmonary microvascular endothelial cell cultures as substrate. Control samples were based on patients who were clinically well at the time of the biopsy. RESULTS: All presented with a deterioration in respiratory function. All patients had elevated factor VIII levels; the levels were significantly greater compared with pretransplantation baseline values (P =<0.03). The biopsy specimens were remarkable for septal capillary necrosis with significant septal capillary deposition of C1q, C3, C4d, and/or C5b-9 along with immunoglobulin, including IgG, with variable endothelial cell localization. The degree of septal capillary necrosis was significantly less in posttransplantation patients who were clinically doing well ( P<0.0001) as was the degree of C1q, C3, C4d, and C5b-9 ( P<0.05). Indirect antiendothelial cell antibody studies were positive in most patients. Treatment interventions included plasmapheresis, resulting in functional improvement: the postpheresis biopsy specimens showed a reduction in both the degree of septal capillary injury (P <0.0003) and the amount of C1q, C3, C4d, and C5b-9 deposition (P <0.05). CONCLUSIONS: Septal capillary injury accompanied by direct and indirect immunofluorescent evidence of humoral immunity is a frequent finding on transbronchial biopsies. The findings suggest that humoral immunity to endothelial-based alloantigen is a common occurrence in lung grafts and may be a critical factor in chronic graft dysfunction.