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PubMed1998

Persistence of a multidrug-resistant Pseudomonas aeruginosa clone in an intensive care burn unit.

Long-term colonization of various body sites with a multidrug-resistant Pseudomonas aeruginosa clone (resistant to piperacillin, cefoperazone, ceftazidime, aztreonam, imipenem, cefepime, cefpirome, ofloxacin, ciprofloxacin, minocycline, and aminoglycosides) with subsequent severe infections in burn patients has not been reported previously. Thirty-nine isolates of multidrug-resistant P. aeruginosa (resistant to ceftazidime and at least three of the agents listed above) recovered from various clinical samples from three patients in an intensive care burn unit from April 1997 to May 1997 and seven preserved isolates recovered from six patients in other medical wards at National Taiwan University Hospital from April 1996 to May 1997 were studied for their epidemiological relatedness. The epidemic could be attributed to a multidrug-resistant P. aeruginosa clone belonging to serogroup O:F (serogroup O:4) by means of antimicrobial susceptibility testing, O serogrouping, and analysis of the randomly amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates. The epidemic strain persisted in the three patients for weeks to months; in the meantime, these patients had received multiple antimicrobial agents for the management of intervening episodes of invasive infections (bacteremia, ventilator-associated pneumonia, and/or catheter-related sepsis) caused by this strain, as well as concomitant infections due to other organisms. The strain had been isolated only once previously, from a burn patient who was on the unit in December 1996. The present report, describing a small outbreak due to P. aeruginosa, documents the fact that a single clone of multidrug-resistant P. aeruginosa can cause long-term persistence in different body sites of burn patients and that the colonization can subsequently result in various severe infections.

Burn Units↗

PubMed2004

Fetal relative lung volume: quantification by using prenatal MR imaging lung volumetry.

PURPOSE: To retrospectively determine a biometric algorithm for calculating relative lung volume in fetuses with normal lungs and of a wide range of gestational ages by using proved independent variables and to retrospectively investigate the use of this algorithm in fetuses with pulmonary hypoplasia. MATERIALS AND METHODS: Total lung volume (TLV) was measured by using planimetry on single-shot rapid acquisition with relaxation enhancement magnetic resonance (MR) images obtained in 91 fetuses with ultrasonographically (US) normal chests and 28 fetuses with US-determined pulmonary hypoplasia. All fetuses were aged between 18 and 38 weeks gestation. Analysis of covariance was used to identify parameters that were not different between the fetuses with US-determined normal and those with US-determined abnormal chests, and these variables were used to construct an algorithm for calculating predicted lung volume. The relative lung volume-that is, the observed lung volume expressed as a percentage of the predicted lung volume-was then calculated in fetuses with pulmonary hypoplasia. RESULTS: There was no significant difference in mean maternal or gestational age between the two fetus groups. Stepwise regression analysis was used to generate the following equation for predicting fetal lung volume on the basis of independent biometric indexes, with a correlation coefficient of 0.93: TLV = (0.52 . LV) + (0.33 . BD) - (0.06 . FL) - 13.7, with TLV and liver volume (LV) in milliliters and biparietal diameter (BD) and femoral length (FL) in centimeters. In the fetuses with normal chests, relative lung volume varied between 51% and 134%. In the fetuses with pulmonary hypoplasia, relative lung volume varied between 6% and 70%. CONCLUSION: The predicted lung volume in fetuses of a wide range of gestational ages can be calculated with a high degree of accuracy, enabling prenatal MR imaging lung volumetry in which relative lung volume is used to quantify fetal pulmonary hypoplasia.

Adolescent↗

PubMed2000

Hepatitis C virus infection: immune responsiveness and interferon-alpha treatment.

Hepatitis C virus (HCV) is responsible for most cases of posttransfusion hepatitis and sporadic or community-acquired non-A, non-B hepatitis. Different generations of enzyme-linked immunosorbent assay have been generated for detecting antibodies to HCV epitopes. HCV-RNA quantitative analysis has been developed by means of polymerase chain reaction technique. This approach is the only reliable method for HCV-RNA tissue localization, being helpful in early diagnosis. HCV infected liver is characterized by an inflammatory infiltrate including CD4+, CD8+, and B lymphocytes. Evidence has been provided that in HCV patients CD8+ cell response is associated with low level of viraemia and higher level of disease activity. CD4+ T cells exhibit specificity for the core antigen, also correlating with disease activity and viraemia. Costimulatory molecules, cytokines, oxygen radicals, the complex Fas/Fas-ligand and soluble class I HLA structures are discussed as putative cofactors involved in disease evolution. Various forms of interferon (IFN)-alpha have been evaluated for the treatment of patients with HCV infection. Initial enthusiasm has been attenuated by the evidence of a low sustained virological response rate and the constant side effects of IFN-alpha therapy in patients with chronic HCV disease. Among possible markers for predicting therapeutic outcome in HCV-positive individuals, anti-core antibodies correlate positively with response to IFN-alpha administration, as well as reduction of interleukin-2 serum levels has been detected in patients with a good therapeutic response. Association between HCV infection and autoimmune phenomena, also in relation to IFN-alpha therapy has been reported. Finally, results of the combined treatment with IFN-alpha/ribavirin are illustrated.

Arachidonic Acid↗

PubMed1988

[Ovarian changes in the progeny of females subjected to prolonged cooling].

The ovaries of immature offspring of the females, subjected to cooling (+5 degrees-+7 degrees C) for 80 days (including pregnancy period) have been investigated. As a control the ovaries of immature offspring of the females, living in the vivarium have been studied. By means of the light optic, electron microscopic, fluorescent-histochemical and morphometric methods, analysis of the generative structures and activity of the sympathetic innervation of the ovaries of performed. Ultramicroscopic organization of ovocytes with early signs of destruction is examined. In the animals of the test group total number of follicles and indices of sympathetic mediation of the ovaries decrease, while more than two-fold increase of ovocytes with signs of destruction is noted, predominantly in the primordial follicles. Thus, a prolonged adaptation of the female to cooling results in certain changes of the ovarian reproductive function in the offspring.

Animals↗

PubMed1993

Detection of epidermal growth factor and transforming growth factor alpha protein in meningiomas and other tumors of the central nervous system in human beings.

Epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) are potent mitogens for normal cells of ectodermal and mesodermal origin. Evidence is accumulating that suggests that EGF, TGF alpha and their common receptor (EGF/TGF alpha-R) influence development and functioning of tissues of the central nervous system (CNS). To further investigate the possible roles of EGF, TGF alpha and their receptor in autocrine/paracrine regulation of tumor growth in the CNS, a series of tumors of the CNS were analyzed for the presence of specific, high affinity EGF/TGF alpha receptors and for the presence of immunoreactive TGF alpha protein. Binding of 125I-EGF to crude membranes from a pool of meningiomas was competed for equally well by low concentrations of unlabeled EGF or TGF alpha, but not by high concentrations of other protein hormones, demonstrating the high degree of specificity of the EGF/TGF alpha receptor. Specific binding of 125I-EGF was dependent upon time and temperature, with maximum specific binding achieved after two hours at 22 degrees C. Scatchard analysis of six tumors of the CNS large enough to permit titration analysis generated linear plots with an average kilodalton of 1.1 +/- 0.1 nanometer (+/- standard error of the mean), suggesting the presence of a single class of EGF/TGF alpha-R with high affinity. EGF also stimulated phosphorylation of a 170 kilodalton protein in membrane fraction of a meningioma, demonstrating that the EGF/TGF alpha-R in this tumor retained EGF-stimulated kinase autophosphorylating activity. Membranes for 17 additional smaller tumors of the CNS were analyzed for specific binding of 125I-EGF by single, high concentration method, and all 17 tumors were found to contain specific binding of 125I-EGF. The average level of 125I-EGF for all 23 tumors of the CNS was 46 +/- 27 femtomoles per milligram protein with a range of 1 femtomoles per milligram for both a pituitary adenoma and meningioma to 638 femtomoles per milligram for a glioblastoma. A series of 13 tumors of the CNS were analyzed for EGF alpha with use of a specific radioimmunoassay. TGF alpha immunoreactive protein was detected in all four malignant tumors of the CNS assayed at an average level of 2.6 +/- 1.1 nanograms per milligram soluble protein, whereas TGF alpha immunoreactive protein was detected in only two of nine benign tumors of the CNS. These results add support to the hypothesis that TGF alpha and its receptor may act by autocrine/paracrine mechanisms to influence growth of tumors of the CNS in vivo.

Central Nervous System Neoplasms↗

PubMed1997

Vagal nerve monitoring: a comparison of techniques in a canine model.

HYPOTHESIS: An optimal technique exists for intraoperative, electrophysiologic vagal nerve monitoring. BACKGROUND: Analogous to facial nerve monitoring during lateral skull base surgery, vagal nerve monitoring may be used at surgery involving the jugular foramen, the posterior cranial fossa, the infratemporal fossa, the parapharyngeal space, and the thyroid gland to decrease the incidence of iatrogenic injuries. Laryngeal electromyography (EMG) is an accurate test of vagal nerve function: four applications have been described for use intraoperatively. The purpose of this study was to compare the sensitivities of these techniques in a canine model in order to identify the optimal method of intraoperative vagal nerve monitoring. METHODS: Four techniques of EMG vagal nerve monitoring were studied in dogs. The thyroarytenoid muscle (TA) was monitored directly in three techniques. Two methods used bipolar hookwire electrodes (L.A. Diagnostics, Los Angeles, CA) inserted in the TA percutaneously through the cricothyroid membrane or via direct laryngoscopy (DL). The third TA monitoring technique involved the use of an EMG endotracheal tube (Xomed-Treace, Jacksonville, FL). The fourth technique used a laryngeal surface EMG electrode (RLN Systems, Jefferson City, MO), laryngoscopically placed in the postcricoid space. After placing each monitoring device, the vagus nerve was identified bilaterally in the neck. The nerves were sequentially stimulated at a constant current of 4.1 Hz with increasing intensity (starting at 0.05 mAmps) to determine the minimum thresholds to stimulate vocal cord contraction. A positive response at the vocal cord was defined as a train of four contractions of > or = 50 mV. The lowest threshold for each technique in each dog was recorded. RESULTS: A positive response was obtained in 27 of 32 possible cases using a maximum boundary of 0.5 mAmps for stimulus intensity. Survival analysis was then used to generate Kaplan-Meier survival curves, allowing a comparison of the mean time needed to obtain a response. Log-rank chi statistics showed that the survival curves are inhomogenous (degrees of freedom [df] = 3, chi = 15.58, p < 0.001). The laryngeal surface electrode appears to offer the most sensitive method for vagal nerve monitoring. CONCLUSIONS: Four techniques of intraoperative, EMG vagal nerve monitoring were compared in a canine model. The results suggest that EMG recordings can be obtained successfully through a variety of techniques and that the laryngeal surface electrode appears to be the most sensitive technique in the canine model.

Animals↗

PubMed2007

FLAME, a novel fuzzy clustering method for the analysis of DNA microarray data.

BACKGROUND: Data clustering analysis has been extensively applied to extract information from gene expression profiles obtained with DNA microarrays. To this aim, existing clustering approaches, mainly developed in computer science, have been adapted to microarray data analysis. However, previous studies revealed that microarray datasets have very diverse structures, some of which may not be correctly captured by current clustering methods. We therefore approached the problem from a new starting point, and developed a clustering algorithm designed to capture dataset-specific structures at the beginning of the process. RESULTS: The clustering algorithm is named Fuzzy clustering by Local Approximation of MEmbership (FLAME). Distinctive elements of FLAME are: (i) definition of the neighborhood of each object (gene or sample) and identification of objects with "archetypal" features named Cluster Supporting Objects, around which to construct the clusters; (ii) assignment to each object of a fuzzy membership vector approximated from the memberships of its neighboring objects, by an iterative converging process in which membership spreads from the Cluster Supporting Objects through their neighbors. Comparative analysis with K-means, hierarchical, fuzzy C-means and fuzzy self-organizing maps (SOM) showed that data partitions generated by FLAME are not superimposable to those of other methods and, although different types of datasets are better partitioned by different algorithms, FLAME displays the best overall performance. FLAME is implemented, together with all the above-mentioned algorithms, in a C++ software with graphical interface for Linux and Windows, capable of handling very large datasets, named Gene Expression Data Analysis Studio (GEDAS), freely available under GNU General Public License. CONCLUSION: The FLAME algorithm has intrinsic advantages, such as the ability to capture non-linear relationships and non-globular clusters, the automated definition of the number of clusters, and the identification of cluster outliers, i.e. genes that are not assigned to any cluster. As a result, clusters are more internally homogeneous and more diverse from each other, and provide better partitioning of biological functions. The clustering algorithm can be easily extended to applications different from gene expression analysis.

Algorithms↗

PubMed2000

Comparison of restricted maximum likelihood and method R for estimating heritability and predicting breeding value under selection.

Method R and Restricted Maximum Likelihood (REML) were compared for estimating heritability (h2) and subsequent prediction of breeding values (a) with data subject to selection. A single-trait animal model was used to generate the data and to predict breeding values. The data originated from 10 sires and 100 dams and simulation progressed for 10 overlapping generations. In simulating the data, genetic evaluation used the underlying parameter values and sires and dams were chosen by truncation selection for greatest predicted breeding values. Four alternative pedigree structures were evaluated: complete pedigree information, 50% of phenotypes with sire identities missing, 50% of phenotypes with dam identities missing, and 50% of phenotypes with sire and dams identities missing. Under selection and with complete pedigree data, Method R was a slightly less consistent estimator of h2 than REML. Estimates of h2 by both methods were biased downward when there was selection and loss of pedigree information and were unbiased when no selection was practiced. The empirical mean square error (EMSE) of Method R was several times larger than the EMSE of REML. In a subsequent analysis, different combinations of generations selected and generations sampled were simulated in an effort to disentangle the effects of both factors on Method R estimates of h2. It was observed that Method R overestimated h2 when both the sampling that is intrinsic in the method and the selection occurred in generations 6 to 10. In a final experiment, BLUP(a) were predicted with h2 estimated by either Method R or REML. Subsequently, five more generations of selection were practiced, and the mean square error of prediction (MSEP) of BLUP(a) was calculated with estimated h2 by either method, or the true value of the parameter. The MSEP of empirical BLUP(a) using Method R was greater than the MSEP of empirical BLUP(a) using REML. The latter statistic was closer to prediction error variance of BLUP(a) than the MSEP of empirical BLUP(a) using Method R, indicating that empirical BLUP(a) calculated using REML produced accurate predictions of breeding values under selection. In conclusion, the variability of h2 estimates calculated with Method R was greater than the variability of h2 estimates calculated with REML, with or without selection. Also, the MSEP of EBLUP(a) calculated using estimates of h2 by Method R was larger than MSEP of EBLUP(a) calculated with REML estimates of h2.

Animal Husbandry↗

PubMed1998

The chromatin pattern of cell nuclei is of prognostic value for renal cell carcinomas.

Using a series of 105 renal cell carcinomas (RCCs) we investigated whether features quantitatively describing the appearance of Feulgen-stained nuclei and, more particularly, of their chromatin (on the basis of computer-assisted microscopy) can contribute any significant prognostic information. Thirty morphonuclear and 8 nuclear DNA content-related variables were thus generated. The actual prognostic values of this set of cytometric variables was compared (by means of discriminant statistical analysis) to conventional diagnostic and/or prognostic markers including histopathological grades, tumour invasion levels and the presence or absence of metastases. We obtained complete clinical follow-ups for 49 of the 105 RCC patients under study, making it possible to define a subset of patients with a bad prognosis (i.e., who died in the 12 months following nephrectomy) and a subset of patients with a good prognosis (i.e., who survived at least 24 months following nephrectomy). An original method of data analysis related to artificial intelligence (decision tree induction) enabled a strong prognostic model to be set up. In the case of 10 new patients, this model identified all the dead patients as having a bad survival status, with a total of 8 correct predictions. Another prognostic model similarly generated enabled the correct predictions to be confirmed.

Adult↗

PubMedDate not supplied

Analysis of stress patterns in the human mandible.

Replicas of a dentate human mandible were prepared in photoelastic resin material. They were positioned in a supporting frame by means of struts, representing the principal muscles of mastication. Occlusal loading was simulated, and the stresses generated within the models were examined by three-dimensional photoelastic stress analysis.

Dental Stress Analysis↗

PubMedDate not supplied

Computer-aided semen analysis variables as predictors of male fertility potential.

A computer-aided semen analysis (CASA) was used to allow digitizing the motion of the spermatozoon. This procedure allows an objective means of judging semen quality, especially the translational movements of spermatozoa. Forty-three couples were included in the study. The average age of the male was 35.5 +/- 4.7 years and that of the female was 32.7 +/- 4.7 years. The average duration of infertility was 3.8 +/- 2.3 years. Using multiple linear regression analysis of 26 prognostic variables, a cluster of 8 variables significantly predicted pregnancy maximally. The 8 variables and the resultant multiple correlation coefficients were used to generate a multiple regression equation which allowed the correct separation of the population into fertile and infertile couples. The mean pregnancy predictor values of the fertile and infertile populations were significantly different using the analysis of variance.

Adult↗

PubMed1999

[Prevention of atrial fibrillation by atrial-based pacemaker implantation].

A large number of studies have demonstrated the long term disadvantage of single lead ventricular pacing in sick sinus syndrome. Ventricular pacing mode predicts chronic atrial fibrillation in patients with preimplant paroxysmal atrial fibrillation. The goal of the report was to study the effectiveness of single atrial and dual chamber (atrio-ventricular sequential) pacemaker treatment in the prevention of atrial fibrillation for patients with sick sinus syndrome complicated with paroxysmal atrial fibrillation. In our university hospital 16 atrial based 5 and dual chamber 11 pacemaker were implanted for treatment of patients with sick sinus syndrome (with or without AV conduction disturbances) complicated with paroxysmal atrial fibrillation. The mean age were 61 (24-78), nine males and seven females. Before or during pacemaker implantation sinus node and AV node function analysis, and echocardiography were performed. There were no surgical complications, lead and/or generator failure. All patients had routine follow-up performed at 4 weeks, 3 months, 6 months. Mean follow up was 31 +/- 8 months (range 3 to 93 months). The atrial based and dual chamber pacing were effective in 90% of our cases. In one patient the treatment had to be combined with propafenone. According to our result, the atrial based pacing may be used to reduce the incidence of atrial fibrillation with careful programming of the base atrial pacing rate, and it is associated with lower frequencies of thromboembolic complications and pacemaker syndrome.

Arrhythmias, Cardiac↗

PubMed1986

Genetics of Darwinian fitness. III. A generalized approach to age structured selection and life history.

Most models in life history assume that maximization of lambda holds. Demographic genetic theory supports this assumption provided (i) the fecundity of each mating is determined solely by the age and genotype of the female, (ii) the two sexes experience the exact same selection intensities, and (iii) the two sexes are equal in their age specific schedules of survival and fecundity. But these assumptions will often not hold in nature: thus a more general means of analysis closely integrated with a broader genetic treatment is attempted here. First, operators are derived to map sex specific non-overlapping generation models into the more general case in which generations can overlap. Application of such operators then suggests a broader representation of age structured selection in which evolution acts according to a single composite Wrightian topography whose gradient is a weighted mean taken over selective gradients in all of the age classes. Application of this view is straightforward, showing, for example, that (i) the evolutionary maximization of lambda, which is the basis of present optimization theories for life history, is extremely fragile with biological deviation from mathematical assumptions used in its derivation, (ii) the cost of meiosis argument is shown not to conflict with traditional life history theory, although its correct application will depend critically and subtly upon how genic effects on fertility are measured, and (iii) correct weightings for age specific selection converge to those of Hamilton (1966) and Schaffer (1974) only when sex specific differences in fertility and survival are nonexistent or when selection occurs only in the demographically dominant sex. For life history problems beyond assumptions underlying tradition approaches the composite adaptive topography seems to provide a suitable alternate means for analysis.

Adaptation, Physiological↗

PubMed2001

Rethinking ethnography: reconstructing nursing relationships.

AIMS OF THE STUDY: Critical ethnography is being adopted increasingly by nurses as a legitimate form of research methodology. This paper explores the research practices and dilemmas that emerge from this methodology using a recently completed ethnographic study of nurse-nurse and nurse-doctor interactions in a critical care hospital setting. BACKGROUND: Critical ethnography provides a useful methodology that facilitates mutual dialogue among participants. It may be limited, however, by the central role of researchers and by a tendency to negotiate participants' realities according to a particular 'truth'. These concerns have been strongly critiqued by poststructuralists using concepts such as discourse, subjectivity and power. By incorporating the notion of a poststructural analysis into critical ethnography, researchers are in a position to examine critically the tensions in their own practices, and their struggles with documenting and analysing ethnographic accounts. DESIGN: Six registered nurses comprised the participants of the research group. Through the method of professional journalling, the first author of this paper explored her professional interactions with doctors and other nurses in her role as a nurse in the critical care setting under investigation. Other methods included participant observation, and individual and focus group interviews with nurse participants. ISSUES OF METHODOLOGICAL CONCERN: This paper considers three issues of methodological concern: researcher/participant subjectivity; the movement from empowerment to reflexivity and the construction of one form of ethnographic 'truth'. These issues are discussed in reference to the research relationships with the nurse participants and the process of analysing ethnographic accounts. CONCLUSIONS: In working with critical ethnography using a poststructural analysis, we were able to generate valuable insights about previously hidden areas of relationships among nurse participants in a research group during all stages of the research process. It also provided a means of informing the analysis of ethnographic texts.

Anthropology, Cultural↗

PubMed1994

[An analysis of Korean women's reproductivity].

An analysis of reproductivity is mainly concerned with the measurement of net force of fertility expressed in terms of a generation rather than in a given year. The present study examined current trends of Korean Women's reproductivity interpreting general reproduction and net reproduction rates, intrinsic rate of natural increase and mean length of gestation. The data used for this analysis were drawn from the national fertility surveys from 1970 through 1990 conducted by the Korea Institute for Population and Health. The figures of the present study revealed that the reproduction rates of Korea during the last 20 years decreased from 2.22 in 1970 to 0.71 in 1990 and net reproduction rates also dropped from 1.9 to 0.69 during the same period of time. Furthermore, from this study, it is noticed that the replacement level of fertility had been reached since the early 1980s. The intrinsic rate of natural increase as measure of population growth under existing conditions of fertility and mortality and free of the influence of the current age distribution, is computed. The level of rate was not much changed and was 0.3 in 1970 compared with 0.25 in 1990, which is still higher than other developed countries. The mean age of mother at the birth of their daughters defined as the length of generation has been slightly changed from 23.9 in 1971 to 25.8 in 1990.

Age Factors↗

PubMed1984

[A clinico-physiological study on the generators of short latency somatosensory evoked potential].

The purpose of this paper is to locate the generators of each wave component in the short latency somatosensory evoked potential (SSEP), by means of cumulative analysis of the SSEP obtained from various localized lesions in the upper cervical cord through brain stem and cerebral subcortical structures. Since there are considerable inconsistency of naming each component in the literature, SSEP to median nerve stimulation of 10 normal subjects were examined by two different recordings, i.e. recording from an electrode at the parietal scalp with a reference electrode on Erb's point (Par.-Erb), and the other at the frontal scalp with a reference electrode on Cv 7 (Fro.-Cv 7), and the SSEP was carefully studied. In normal subjects, the SSEP by Par.-Erb lead yielded 5 negative components (N 7, N 11, N 16, N 18 & N 26) and 4 positive components (P 9, P 13, P 22 & P 42), while by Fro.-Cv 7 5 negative components (N 7, N 10, N 12, N 16 & N 28) and 5 positive components (P 9, P 11, P 13, P 20 & P 44). Thirty three patients were subjected to analyse the influence of localized lesions to each component of the SSEP and the recording was evaluated in regard to (a) identification of each component, (b) latency of each component and inter-peak latency difference exceeding 2 SD, and (c) over 50% asymmetry and laterality of the amplitude. Cervical spondylotic myelopathy, high cervical cord tumor, tonsillar herniation, pontine infarct and hemorrhage, circumscribed thalamic lesion, and vascular lesion of centrum semiovale were carefully examined with CT scan and the findings were compared with neurological findings periodically. SSEP was taken repeatedly, especially before and after operative intervention, and alteration of the component was referred to the clinical progress of the lesion. In conclusion, results obtained from our present observation indicated that P 9 was the extramedullary projection, P 11 was intramedullary origin of the lower cervical cord, P 13 was medulla oblongata origin and P 13-N 16 was projection from medulla oblongata to thalamus. N 16-N 18 and N 26 were considered projection from thalamus to hand area of the parietal lobe with some association area and N 28 had the generator widely based on frontal projection system. These findings appeared to be quite useful for topographic diagnosis and functional evaluation of the lesions in central nervous system.

Adolescent↗

PubMed1996

Transthoracic bioimpedance can measure extravascular lung water in acute lung injury.

We used a porcine endotoxemic model of acute lung injury to compare extravascular lung water (EVLW) measured by right transthoracic bioimpedance to postmortem gravimetric EVLW measurements. Adult pigs were randomized into control (N = 5) or endotoxin groups [150 microgram/kg Escherichia coli lipopolysaccharide B for 1 hr followed by 3 hr of resuscitation for a thermodilution cardiac output less than 90% of baseline using either isotonic saline (N = 5) or isooncotic albumin (N = 5)]. Right lung resistance was measured using a novel electrode array and a highly sensitive analyzer and was used to calculate right lung resistivity. At the end of the experiment, animals in the endotoxin-albumin group had higher gravimetric EVLWs than those in the endotoxin-saline or control groups (P < 0.05). Right lung resistivity corrected for body weight significantly correlated with gravimetric EVLW (r2 = 0.49; SEE = 0.96; P = 0.0038). Using multiple regression analysis, a predictive equation for EVLW based on right lung resistivity, body weight, and mean pulmonary artery pressure was generated (r2 = 0.81; SEE = 0.60; P < 0.0001). These results demonstrate that right lung resistivity measurements can provide a noninvasive estimate of EVLW. In addition, crystalloid may be preferable to colloid for fluid resuscitation in noncardiogenic pulmonary edema.

Animals↗

PubMed1997

Hemodynamic data and survival in children with pulmonary hypertension.

OBJECTIVES: Using data from a multi-institutional data base, we sought to determine whether hemodynamic data predict duration of survival in children with primary or secondary pulmonary hypertension. BACKGROUND: Lung transplantation is a therapeutic option for children with pulmonary hypertension. Appropriate timing of lung transplantation requires reliable methods of predicting duration of survival in potential candidates. METHODS: A regional data base was used to obtain cardiac catheterization data on 50 children with mean pulmonary artery pressure (mPAP) > 25 mm Hg and indexed pulmonary resistance (Rp) > 4.5 Wood units. Data on survival were obtained from the participating centers. RESULTS: There were 15 patients without congenital heart disease (group 1) and 35 patients with congenital heart disease (group 2) for analysis. Actuarial survival at 1, 2 and 5 years was 86%, 69% and 69% in group 1 and 88% and 77% in group 2, respectively (p = NS). Hemodynamic variables that predicted survival on univariate analysis were mean right atrial pressure (mRAP) (p < 0.0001), mPAP (p = 0.034), Rp (p < 0.0001) and pulmonary flow (p = 0.003), as well as a variable that we generated-mRAP x Rp (p < 0.0001). On multivariate stepwise logistic regression analysis, mRAP x Rp was independently related to survival. A model using mRAP x Rp allows for the estimation of probability of death at 1 and 2 years after catheterization. CONCLUSIONS: Hemodynamic variables can predict survival in children with pulmonary hypertension in the presence or absence of congenital heart defects. This information can be used to determine the optimal timing of listing for lung transplantation.

Blood Pressure↗