Variability in intraosseous flush practices of emergency physicians.

OBJECTIVE: Intramedullary pressure changes during intraosseous (IO) procedures have been implicated in the intravasation of bone marrow fat and with pain in conscious patients. The objective of this study was to demonstrate inter-provider variability in pressures generated during initial flush procedures. METHODS: IO cannulas were inserted into the proximal tibiae and humeri by study personnel. A second cannula was placed in the mid diaphysis of each bone to record intramedullary pressures. Fifteen emergency physicians performed 60 flushes in random order in two cadavers while flush duration and IO pressure were continuously recorded. Providers were blinded to the flush pressures they generated and the flush techniques of others. RESULTS: The median IO pressure (IOP) generated by providers was 903 mm Hg (range, 83-2941 mm Hg) and the median flush duration was 5.2 seconds (range, 1.0-13.4 seconds). Significant differences were noted among providers in peak IOP generated (analysis of variance P<.001). Providers were consistent in the forces they generated relative to each other. An inverse, nonlinear relationship was observed between flush duration and the peak IOP generated. Significant differences were noted in intramedullary flush pressures at flush sites within cadavers (analysis of variance P: cadaver #1 P<.001; cadaver #2 P=.012). CONCLUSIONS: The IO compartment pressures generated by physicians demonstrated significant interoperator variability with greater than 35-fold difference in flush forces, and an inverse relationship between intraosseous pressure and flush duration. It may be prudent practice for providers to extend the flush over several seconds, thus limiting maximal pressures.

Rosiglitazone versus rosiglitazone and metformin versus rosiglitazone and losartan in the treatment of nonalcoholic steatohepatitis in humans: a 12-month randomized, prospective, open- label trial.

UNLABELLED: Medication combinations that improve the efficacy of thiazolidinediones or ameliorate weight-gain side effects of therapy represent an attractive potential treatment for (NASH). The aim of this randomized, open-label trial was to assess the efficacy of rosiglitazone and metformin in combination versus rosiglitazone and losartan, compared to rosiglitazone alone, after 48 weeks of therapy. A total of 137 subjects with biopsy-proven NASH were enrolled and randomly assigned to receive either 4 mg twice-daily of rosiglitazone, 4 mg of rosiglitazone and 500 mg of metformin twice-daily, or 4 mg of rosiglitazone twice-daily and 50 mg of losartan once-daily for 48 weeks. Patients were screened for other etiologies of chronic liver disease, including daily alcohol intake in excess of 20 g. Repeat liver biopsy was performed after 48 weeks of therapy and reviewed in a blinded fashion by a single expert hepatopathologist. The primary aim of the study was to assess for differences between treatment groups in the improvement of steatosis, hepatocellular inflammation, and fibrosis. In total, 108 subjects completed the trial. Primary outcome revealed no significant difference between treatment groups in all histologic parameters (steatosis, P = 0.137; hepatocellular inflammation, P = 0.320; fibrosis, P = 0.229). Overall improvement in steatosis, hepatocellular inflammation, ballooning degeneration, and fibrosis was observed (P ≤ 0.001). Serum aminotransferases were reduced in all three groups (P < 0.001 within treatment, P > 0.05 between groups). Metformin did not significantly mitigate weight gain (P = 0.051). CONCLUSIONS: Forty-eight weeks of combination therapy with rosiglitazone and metformin or rosiglitazone and losartan confers no greater benefit than rosiglitazone alone with respect to histopathology.

Virological and serological characterization of SRV-4 infection in cynomolgus macaques.

The nature of SRV-4 infection in cynomolgus macaques remains unclear to date. Here, we report the monitoring of 24 cynomolgus monkeys that were naturally infected with SRV-4 for virus isolation, proviral load and antibody. The results indicated that the SRV-4 antibody status was statistically correlated to environmental temperature.

Induction pegylated interferon alfa-2b in combination with ribavirin in patients with genotypes 1 and 4 chronic hepatitis C: a prospective, randomized, multicenter, open-label study.

BACKGROUND & AIMS: Standard of care (SOC) treatment for chronic hepatitis C (CHC) involves weekly pegylated (PEG) interferon plus weight-based ribavirin with resultant sustained virologic response (SVR) rates at or near 50% for genotypes 1 and 4 virus. Induction therapy with higher doses of PEG interferon may improve first-phase viral kinetics and thus improve the overall SVR in genotypes 1 and 4 patients. METHODS: This multicenter, randomized, open-label trial enrolled treatment-naive genotypes 1- and 4-infected CHC patients to either initial induction therapy versus SOC. The induction group received PEG interferon alfa-2b 3.0 mcg/kg/wk for 12 weeks followed by PEG interferon alfa-2b 1.5 mcg/kg/wk for 36 weeks and 13 +/- 2 mg/kg ribavirin daily for 48 weeks. SOC patients received PEG interferon alfa-2b 1.5 mcg/kg weekly for 48 weeks and 13 +/- 2 mg/kg ribavirin daily for 48 weeks. The primary end point was SVR. RESULTS: There were 610 patients enrolled throughout the United States. Complete early virologic response was 62.6% versus 57.7% in induction versus SOC (NS). Overall SVR was 32% in induction versus 29% in SOC group (NS). Dose reduction of either PEG interferon (24.1% vs 23.8%) or ribavirin (26.8% vs 25.1%) was similar between the 2 groups. There was a trend toward a significant difference when comparing the SVR in induction therapy in patients weighing more than 85 kg versus those receiving SOC (38% vs 28%; P = .08). CONCLUSIONS: Induction therapy does not enhance complete early virologic response or SVR rates in a predominantly genotype 1 CHC population compared with SOC therapy.

Hospice enrollment for terminally ill patients with gynecologic malignancies: impact on outcomes and interventions.

OBJECTIVE: To determine survival and interventions for patients with non-curative gynecologic malignancies based on supportive care enrollment. METHODS: An IRB approved retrospective review identified patients with recurrent/persistent gynecologic cancers from 2002 to 2008. Demographics, therapy, clinicopathologic data, hospice utilization, surgical/invasive procedures and survival were collected. Patients were considered hospice enrollees if they enrolled following recommendation from their provider (HOSPICE); however, patients that declined hospice when recommended were considered (NO HOSPICE), regardless if they ultimately received supportive care. Standard statistical tests including: t-test and Kaplan-Meier with Log Rank were used. RESULTS: Eighty-one patients were identified: 29 patients (36%) NO HOSPICE and 52 (64%) HOSPICE. Mean age was 61. Most patients had ovarian cancer (54.3%), were white (61.7%) and had disease recurrence (72%). Patients utilized a median of 3 anti-neoplastic therapies (range 0-10) for recurrent or progressive/persistent disease. Median time receiving hospice care was 1week for NO HOSPICE patients versus 8weeks HOSPICE patients (p<0.0005). In a subset of patients with recurrent disease, median overall survival for NO HOSPICE patients was 9months (95% CI 5.9-12.1months) versus 17months (95% CI 11.1-22.9months) for HOSPICE patients (p=0.002). NO HOSPICE patients were more likely to have a procedure performed (55% vs. 31%) within 4weeks of their death, including the administration of chemotherapy OR 2.4 (95% CI 1.1-7.1, p=0.036). CONCLUSIONS: While retrospective reviews evaluating hospice are challenging, our data suggest no detrimental impact on survival for hospice patients. Continued evaluation for patients at the end-of-life is necessary in order to optimize resource utilization.

Cardiac contractility during hemofiltration in an awake model of hyperdynamic endotoxemia.

BACKGROUND: To determine whether continuous veno-venous hemofiltration can ameliorate hemodynamic instability and left ventricular (LV) dysfunction by reducing circulating plasma mediators, the authors used the LV end-systolic elastance (Ees) as a contractility index, in an awake swine model simulating human hyperdynamic endotoxemia. METHODS: Nineteen instrumented pigs were divided into a control group (CTRL, n = 7), a hemofiltration (HF, n = 7) group, and an extracorporeal circuit (ECC, n = 5) only group. All animals received intravenous E. coli endotoxin (10 microg x kg x h) and resuscitation in a common regimen for 24 hours. Hemofiltration was started 30 minutes after initiation of endotoxemia and continued until the end of the experiment. RESULTS: : Ees was maintained at baseline levels in the HF group, whereas a progressive decrease of Ees was found in both the CTRL and the ECC groups. Cardiac output was significantly higher in the HF group than the CTRL group. There was no significant difference between the groups in plasma catecholamines. CONCLUSION: We conclude that hemofiltration prevented LV impairment.

Feasibility study of noninvasive ventilation with helium-oxygen gas flow for chronic obstructive pulmonary disease during exercise.

BACKGROUND: Individually, noninvasive ventilation (NIV) and helium-oxygen gas mixtures (heliox) diminish ventilatory workload and improve exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). NIV in combination with heliox may have additive effects on exercise tolerance in severe COPD. METHODS: We assessed the safety, tolerability, and efficacy of heliox and NIV during exercise in patients with severe COPD. SETTING: Pulmonary rehabilitation facility in an academic tertiary-care medical center. PROTOCOL: Twelve patients with severe COPD were enrolled. Using a sequential randomized placebo-controlled crossover study design, the patients performed 4 separate constant-work stationary bicycle cardiopulmonary exercise studies at 80% of maximal workload during application of sham NIV, NIV, 60:40 heliox with sham NIV, and 60:40 heliox with NIV. Tolerability, safety, and exercise duration as determined by constant-work cardiopulmonary exercise test were the primary outcome measures. Secondary outcome measures at peak exercise and iso-time included rate of perceived exertion, dyspnea, leg pain, heart rate, respiratory rate, systolic and diastolic blood pressure, tympanic temperature, and oxyhemoglobin saturation. RESULTS: No adverse effects occurred during or after application of NIV, heliox, or NIV with heliox. Exercise duration using heliox with NIV was significantly longer than both heliox (P = .01) and NIV (P = .007), but not placebo (P = .09). Relative to placebo, all treatment arms permitted lower respiratory rates at peak exercise. Heliox, with or without NIV, was associated with significant improvements in oxyhemoglobin saturation at peak exercise, relative to placebo or NIV alone. CONCLUSIONS: The adjunctive use of NIV with heliox during exercise proved both safe and tolerable in patients with severe COPD. The lack of demonstrable efficacy to any of the treatment arms relative to placebo (P = .09) may be the result of the small sample size (ie, type 2 error)-a conclusion emphasized by the large standard deviations and differences in treatment group variances in exercise duration alone.

Airway humidification during high-frequency percussive ventilation.

BACKGROUND: We were concerned about the risk of inadequate humidification during high-frequency percussive ventilation (HFPV). METHODS: We studied 5 humidifiers during HFPV with a lung model, at bias gas flows of 10 L/min, 30 L/min, and 50 L/min, and compared the results to those from a comparator ventilator/humidifier setup and to the minimum temperature (30 degrees C) and humidity (30 mg/L) [corrected] recommended by the American Association for Respiratory Care, at both regular room temperature and a high ambient temperature. Temperature was measured at the humidifier outflow point and at the artificial carina. Humidity was measured at the artificial carina. RESULTS: Of the 7 HFPV/humidifier combinations, 2 (the MR850 at a bias flow of 50 L/min, and the ConchaTherm Hi-Flow with VDR nebulizer) provided a carinal temperature equivalent to the comparator setup at room temperature, whereas one HFPV/humidifier combination (the ConchaTherm Hi-Flow with modified programming, at bias flows of 30 L/min and 50 L/min) provided a higher carinal temperature. At high ambient temperature, all of the setups delivered lower carinal temperature than the comparator setup. Only 2 setups (the ConchaTherm with modified programming at a bias flow of 50 L/min, and the ConchaTherm Hi-Flow with VDR nebulizer) provided carinal humidification equivalent to the comparator setup, without regard to ambient temperature; the other humidifiers were less effective. The ConchaTherm with modified programming, and the ConchaTherm with the VDR nebulizer provided the most consistent humidification. CONCLUSION: HFPV's distinctive gas-flow mechanism may impair gas heating and humidification, so all humidification systems should be tested with HFPV prior to clinical use.

Histopathologic variability between the right and left lobes of the liver in morbidly obese patients undergoing Roux-en-Y bypass.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) has been shown to occur in >90% of significantly obese patients. At present, diagnosis of the more severe form of NAFLD, nonalcoholic steatohepatitis (NASH), requires a liver biopsy. Conflicting data exist on the degree of sampling variability seen with percutaneous liver biopsy. Our aim was to assess for significant regional differences in histopathology between the right and left lobes of the liver in morbidly obese patients undergoing bariatric surgery. METHODS: Morbidly obese patients undergoing bariatric surgery at Wilford Hall Medical Center were eligible for study enrollment. Patients with chronic liver disease other than NAFLD were excluded. All patients underwent intraoperative liver biopsy, one from the right lobe and one from the left lobe, with a 14-gauge Tru-cut biopsy needle. Histopathologic features of NAFLD were compared by a hepatopathologist who examined biopsy specimens from the 2 hepatic lobes and was blinded to patient identification and site of origin of biopsy. Agreement between the 2 biopsy specimens was assessed by using the kappa coefficient. RESULTS: Forty-three patients (predominantly female) with body mass index median of 46.2 kg/m2 were enrolled. Agreement for steatosis was 93% (kappa = 0.91), inflammation 74% (kappa = 0.58), ballooning necrosis 84% (kappa = 0.73), fibrosis 98% (kappa = 0.96), and for the NAFLD activity score > or =5 was 93% (kappa = 0.83). CONCLUSIONS: Minimal variability was found for steatosis, NAFLD activity score > or =5, and fibrosis in samples of liver obtained from the right and left lobes of the liver in a group of morbidly obese, predominately female patients undergoing bariatric surgery. Histopathologic findings of necroinflammation appear to have the greatest degree of sampling variability. In contrast with previously published data, excellent agreement was seen for fibrosis in biopsy specimens obtained at surgery from right and left lobes of the liver.

Evaluation of white blood cell count, neutrophil percentage, and elevated temperature as predictors of bloodstream infection in burn patients.

OBJECTIVE: To investigate whether specific values of or changes in temperature, white blood cell count, or neutrophil percentage were predictive of bloodstream infection in burn patients. DESIGN: Retrospective review of electronic records. SETTING: Intensive care center at the US Army Institute of Surgical Research Burn Center. PATIENTS: Burn patients with blood cultures obtained from 2001 to 2004. MAIN OUTCOME MEASURES: Temperature recorded at the time blood cultures were obtained; highest temperature in each 6-hour interval during the 24 hours prior to this; white blood cell count and neutrophil percentage at the time of obtaining the blood culture and during the 24 hours preceding the blood culture; demographic data; and total body surface area burned. RESULTS: A total of 1063 blood cultures were obtained from 223 patients. Seventy-three people had 140 blood cultures from which microorganisms were recovered. Organisms that were recovered from blood cultures included 80 that were gram negative, 54 that were gram positive, 3 that were mixed gram positive/gram negative, and 3 yeasts. Although white blood cell count and neutrophil percentage at the time of the culture were statistically different between patients with and patients without bloodstream infection, receiver operating characteristic curve analysis revealed these values to be poor discriminators (receiver operating characteristic curve area = 0.624). Temperature or alterations in temperature in the preceding 24-hour period did not predict presence, absence, or type of bloodstream infection. CONCLUSIONS: Temperature, white blood cell count, neutrophil percentage, or changes in these values were not clinically reliable in predicting bloodstream infection. Further work is needed to identify alternative clinical parameters, which should prompt blood culture evaluations in this population.

Does local anesthesia decrease pain perception in women undergoing amniocentesis?

OBJECTIVE: The null hypothesis is that local anesthesia does not decrease pain perception during amniocentesis. STUDY DESIGN: We performed a prospective randomized study comparing local anesthesia (1% lidocaine) with no anesthesia before amniocentesis in a racially diverse population. Immediately after the procedure, subjects were asked to assess their pain using both a Visual Analogue Scale and a 101-point Numerical Rating Scale. RESULTS: Two hundred four women were enrolled; 101 women received local, 102 women received no local, and 1 woman declined the amniocentesis after randomization. There was no difference in pain perception between the 2 groups as measured by either the visual analogue scale or the numeric rating scale (P = .28 and .18 respectively). The correlation coefficient between the 2 pain scales was strong with 0.86 for the local group and 0.92 for the no local group, (P < .001). CONCLUSION: Administration of local anesthesia before amniocentesis does not decrease maternal pain perception.

Impact of Acinetobacter infection on the mortality of burn patients.

BACKGROUND: Acinetobacter calcoaceticus-baumannii complex (Acb) is recognized as an important cause of nosocomial infections. Although Acb can be associated with multidrug resistance, its impact on mortality in burn patients has not been fully elucidated. STUDY DESIGN: In a retrospective cohort study assessing medical records and microbiology laboratory data at a US military tertiary care burn center, we evaluated all patients admitted to the burn center between January 2003 and November 2005. Data collected included age, severity of burn, comorbidities, length of stay, and survival to hospital discharge. In addition, microbiology data were reviewed to determine which patients were infected with Acb during this time frame. These data were then used to compare patients infected with Acb to patients not infected. Multivariate analysis using logistic regression was performed to determine which patient characteristics were associated with increased mortality. RESULTS: There were 802 patients included in the study. Fifty-nine patients met the case definition for infection. An additional 52 patients were found to be colonized with Acb. Patients with Acb infection had more severe burns and comorbidities, and had longer lengths of stay compared with patients without Acb or those with Acb colonization. Mortality in infected patients was higher compared with those without infection (relative risk = 2.86, p = 0.001). On multivariate analysis, infection with Acb was not statistically associated with mortality. CONCLUSIONS: Multidrug-resistant Acb is a common cause of nosocomial infection in the burn patient population. Despite this, it does not independently affect mortality.

Effect of adult strabismus on ratings of official U.S. Army photographs.

PURPOSE: To determine if strabismus affects the ratings of official U.S. Army photographs. METHODS: Photographs of seven women and seven men officers (subjects) were digitally altered to give the impression of strabismus. Four photographs of each subject were obtained: two in an orthotropic state; one in a left exotropic state; and one in a left esotropic state. The photographs were presented randomly to a panel of 38 raters. Masked to the study design, the raters rated every photograph on a 1 to 10 Likert scale. The results were grouped according to eye alignment: two orthotropic groups, one exotropic group, and one esotropic group. Comparisons of the mean ratings were made between each eye alignment group and based on the subject's gender. RESULTS: The mean rating for each orthotropic group was 5.4 and 5.5 Likert scale units with a SD of 0.8 and 0.9, respectively (group 1 and group 2). The mean rating for the exotropic group was 5.4 Likert scale units with a SD of 0.7. The mean rating for the esotropic group was 5.1 Likert scale units with a SD of 0.8. Significantly lower ratings were obtained for the esotropic group compared with the orthotropic group (p=0.028). Women received significantly lower ratings regardless of eye alignment (p=0.044). CONCLUSIONS: This study indicates that the presence of esotropia negatively affects the rating of an official U.S. Army photograph; furthermore, female gender negatively affects ratings.

Radiographic indicators of ankle instability: changes with plantarflexion.

BACKGROUND: The effect of plantarflexion on radiographic indicators of instability was investigated in matched pairs of stable ankles and unstable ankle fractures with complete deltoid ligament tears to test the hypothesis that differences exist in indicators as a function of either stability or position. The purpose of this study was to determine whether plantarflexion increases radiographic indicators of ankle fracture instability. METHODS: Measurements from 34 patients scheduled for operative treatment of unstable ankle fractures were collected prospectively from normal, stable ankles and the injured, unstable ankles. Instability was defined as a positive fluoroscopic stress examination under anesthesia. Stability and instability and neutral position and plantarflexion were associated with eight radiographic indicators of which five were distances in millimeters and three were binomial (either stable or unstable). RESULTS: Measurements were larger in the unstable ankles than in the normal stable ankles. Plantarflexion was associated with increased distances in stable ankles, and a trend was seen in unstable ankles. Plantarflexion was associated with increased binomial indicators in unstable ankles but not in stable ankles. DISCUSSION: Joint positioning affected measurement of ankle stability: plantarflexion increased the sensitivity of radiographic indicators.

Waterproof versus cotton cast liners: a randomized, prospective comparison.

Casting injured extremities can cause complications (eg, itching, odor, rashes, skin maceration), many of which are associated with the inability to wash the extremity because of water retention and slow drying of conventional cast liners. A waterproof cast liner allows casts to become wet and perhaps improves hygiene and comfort. Fifty-nine patients (age, > or = 10 years) with upper or lower extremity injuries were randomized to a waterproof-liner group (n = 29) or a cotton-liner group (n = 30). Both groups had casts made of fiberglass tape. At each clinic visit, patients and physicians completed questionnaires evaluating comfort and skin condition, respectively. The waterproof-liner group had better scores for itch (P = .008), discomfort (P < .001), irritation (P = .002), overall patient score (P = .012), and overall physician score (P = .049).

Passive biomechanical properties of sutured mammalian muscle lacerations.

Muscle trauma, such as laceration or transection, is a common occurrence, but repairing delicate tissue poses a clinical challenge. This is at least partially due to the lack of established muscle repair models. The purpose of this study was to compare the biomechanical properties of stitches in transected porcine and bovine muscle bellies. A biomechanical protocol was designed for measuring suture performance in muscle belly lacerations. Twenty simple stitches in porcine and 21 stitches in bovine specimens were tested. Individual stitches were placed in lacerated muscle bellies and tensioned on a biomechanical tester (model 8521S, Instron Corporation, Canton, MA). The mean maximum load for porcine (22.0 N) and bovine (23.9 N)stitches was not significantly different (p = .48). The difference in mean strains at maximum load between porcine (9.70/%) and bovine(8.0%0/) groups was statistically significant (p = .004). Failure mechanisms were similar. One porcine stitch avulsed the muscle transversely,while 19 stitches tore out longitudinally. All 20 stitches tore out in bovine specimens. Sutured muscle was the weakest element in each test. The present study demonstrated that sutured muscles performed similarly for the two mammals regarding the parameters of maximum load and mechanism of failure. Regarding suturing of skeletal muscle lacerations, both mammalian models had similar biomechanical performance for maximum loads and failure mechanisms, while strain data differed. The stitch load magnitudes in this study approximate those required to successfully repair transected muscle. Knowledge introduced by this study fills a gap concerning muscle stitching relevant to clinical care.

Use and limitations of magnetic resonance phase-contrast assessment of coronary flow reserve in a model of collateral dependence.

Phase-contrast magnetic resonance imaging (PC-MRI) is useful for assessing coronary artery flow reserves (CFR) in man and acute animal models with intermediate coronary lesions. The present study examines the use of PC-MRI for assessing CFR in a model with critical stenosis and collateral dependence. PC-MRI quantitative flow measurements from the proximal left anterior descending (LAD) and left circumflex (LCX) coronary arteries were compared with myocardial tissue perfusion reserve measurements (microsphere techniques) after placement of a 2.25-mm ameroid constrictor on the proximal LCX in a porcine model; measurements were obtained at implantation (n = 4) and at 3 to 4 weeks (n = 4) and 6 weeks (n = 5) postimplantation. CFR is defined as the ratio of maximal hyperemic flow to baseline flow. Hyperemia was induced using intravenous adenosine (140 mg/kg/min). Collateral dependence in the LCX distri bution was evidenced by angiographic findings of critical stenosis with minimal myocardial histological changes and normal baseline myocardial perfusion (microsphere techniques). In this setting, PC-MRI CFR was correlated with microsphere measures of perfusion reserve. Collateral dependence was confirmed by Evan's blue dye injection. This study provides angiographic, myocardial perfusion, and histological correlates associated with PC-MRI epicardial CFR changes during chronic, progressive coronary artery constriction. It also demonstrates the disparity between epicardial and myocardial measures of coronary flow reserve with collateral dependence and the caveats for PC-MRI use in models of progressive coronary constriction.

Hemorrhage-induced vascular hyporeactivity to norepinephrine in select vasculatures of rats and the roles of nitric oxide and endothelin.

Hemorrhage-induced vascular hyporeactivity to norepinephrine (NE) and the possible effector roles of nitric oxide (NO) and endothelin (ET) were investigated in different vascular beds of rats. Under urethane anesthesia, rats (n = 7 per group) were hemorrhaged to a mean arterial pressure (MAP) of 50 mm Hg for 60 min. A group of rats was pretreated with either NG-nitro-L-arginine methyl ester (10 mg/kg), an NO synthase inhibitor, or PD142893 (0.1 mg/kg), an ET receptor antagonist 15 min before the end of the hypotensive period. Operated, euvolemic rats served as controls. The responses of MAP and the blood flow of the superior mesenteric (SMA), celiac (CA), left renal (LRA), and left femoral arteries (LFA) to NE (3 microg/kg, i.v.) were measured at baseline (prehemorrhage), at the end of the hypotensive period (0 h), and at 1, 2, and 4 h after the end of the hypotensive period. The pressor responses to NE on MAP at 0, 1, 2, and 4 h in the 60-min hemorrhage groups were reduced to 45.9%, 37.8%, 29.2%, 18.4% of baseline pressor response, respectively. At these same times, the fall in blood flow in response to NE in SMA, CA, LRA, and LFA was significantly blunted (P < 0.01). This loss of responsiveness in CA and LFA was more severe than in SMA and LRA (P < 0.05-P < 0.01). Pretreatment with L-NAME or PD142893 significantly improved the pressor response of MAP and the blood flow responses of the four arteries to NE (P < 0.01). Hypotension at 50 mm Hg for 60 min resulted in an apparent loss of vascular reactivity to NE, and the four vasculatures studies were not affected to the same extent. In addition, NO and ET appear to contribute to the loss of vascular reactivity in different vasculatures in hemorrhagic shock.

Validation of the Diesse Mini-Ves erythrocyte sedimentation rate (ESR) analyzer using the Westergren ESR method in patients with systemic inflammatory conditions.

The Diesse Mini-Ves (DMV) erythrocyte sedimentation rate (ESR) analyzer was designed to improve efficiency in determining the ESR. We compared the Westergren ESR method with the 4-sample DMV ESR analyzer for performance and clinical correlation. This prospective observational study, conducted at a 450-bed tertiary medical center, evaluated 291 paired samples from subjects with various systemic inflammatory conditions. Linear regression analysis revealed a statistically significant correlation between the 2 methods. Satisfactory precision of the DMV analyzer was obtained for high and mid-range ESR values. The 4-sample DMV ESR analyzer was precise and comparable in results to the Westergren ESR method. This DMV ESR analyzer is now used at our medical center based on quality control improvements that include a faster, safer, and more standardized ESR method. Hospital or office-based clinical laboratories should consider using the 4-sample DMV ESR analyzer in place of the Westergren method.

Prolonged stability of antimicrobial activity in peritoneal dialysis solutions.

OBJECTIVE: To evaluate the stability of the antimicrobial chemical and bioactivity of gentamicin, vancomycin, and gentamicin and vancomycin in combination, and the stability of the bioactivity of ceftazidime, admixed in standard peritoneal dialysis solutions and then maintained over a 14-day period at room temperature or under refrigeration. SETTING: Peritoneal dialysis center and microbiology laboratory at a military, teaching medical center. MEASUREMENTS: Standard peritoneal dialysate bags admixed with gentamicin, vancomycin, gentamicin and vancomycin in combination, or ceftazidime were stored at either 4 degrees C or 20 degrees C for 14 days. Sequential aliquots were withdrawn and assayed for antibiotic activity by bioassay and, except for ceftazidime, immunoassay for chemical activity. The bioassay was performed using a standardized Kirby-Bauer disc method. Significance was determined by ANOVA and, where the effect size was significant at the p < 0.05 level, the application of the paired t-test or the Wilcoxon signed rank test to the difference in activity between the first and last samples. RESULTS: Antibiotic concentration by immunoassay did not significantly deteriorate over 14 days for vancomycin or gentamicin when either room temperature or refrigerated samples were studied. By bioassay, gentamicin and ceftazidime, but not vancomycin, lost moderate but significant activity over 14 days when refrigerated bags were assayed (except for an insignificant decrement in gentamicin in the combined vancomycin and gentamicin bags). Bags stored at room temperature, in general, lost significant bioactivity over 14 days, but to levels where clinical efficacy would still be expected. The vancomycin bioassay performed on the combination bags demonstrated a remarkably enhanced bioactivity, presumably reflecting synergy with gentamicin. CONCLUSION: These data indicate that the study antibiotics admixed with peritoneal dialysis fluids retain stable chemical activity, whether refrigerated or kept at room temperature, for at least 14 days. A moderate decrement in bioactivity occurred for study antibiotics when stored either refrigerated or at room temperature over 14 days, although clinically significant levels were maintained. The clinical significance of a possible synergy between vancomycin and gentamicin is yet to be determined.