Biomedical subjects

J Vallés

Publications and source records attributed to J Vallés.

At least 19 recordsLinked to original sources

PubMed2005

Antibiotic prescription for community-acquired pneumonia in the intensive care unit: impact of adherence to Infectious Diseases Society of America guidelines on survival.

BACKGROUND: The purpose of our study was to analyze prognostic factors associated with mortality for patients with severe community-acquired pneumonia (CAP). METHODS: We conducted a prospective multicenter study including all patients with CAP admitted to the intensive care unit during a 15-month period in 33 Spanish hospitals. Admission data and data on the evolution of the disease were recorded. Multivariate analysis was performed using the SPSS statistical package (SPSS). RESULTS: A total of 529 patients with severe CAP were enrolled; the mean age (+/-SD) was 59.9+/-16.1 years, and the mean Acute Physiology and Chronic Health Evaluation (APACHE) II score (+/-SD) was 18.9+/-7.4. Overall mortality among patients in the intensive case unit was 27.9% (148 patients). The rate of adherence to Infectious Diseases Society of America (IDSA) guidelines was 57.8%. Significantly higher mortality was documented among patients with nonadherence to treatment (33.2% vs. 24.2%). Multivariate analysis identified age (odds ratio [OR], 1.7), APACHE II score (OR, 4.1), nonadherence to IDSA guidelines (OR, 1.6), and immunocompromise (OR, 1.9) as the variables present at admission to the intensive care unit that were independently associated with death in the intensive care unit. In 15 (75%) of 20 cases of Pseudomonas aeruginosa infection, the antimicrobial treatment at admission was inadequate (including 8 of 15 cases involving patients with adherence to IDSA guidelines). Chronic obstructive pulmonary disease (OR, 17.9), malignancy (OR, 11.0), previous antibiotic exposure (OR, 6.2), and radiographic findings demonstrating rapid spread of disease (OR, 3.9) were associated with P. aeruginosa pneumonia. CONCLUSIONS: Better adherence to IDSA guidelines would help to improve survival among patients with severe CAP. Pseudomonas coverage should be considered for patients with chronic obstructive pulmonary disease, malignancy, or recent antibiotic exposure.

Anti-Bacterial Agents↗

PubMed2001

Presence of polyclonal Pseudomonas aeruginosa in an intensive care unit: a 27-month prospective study on molecular epidemiology.

Pseudomonas aeruginosa was isolated in 22.2% of 305 intensive care unit environmental cultures. A high genetic heterogeneity (18 pulsotypes) was evident. Taps and related surfaces were a stable reservoir for certain pulsotypes. The 15.4% of the P. aeruginosa-positive cultures were polyclonal. Different colony morphotypes should be assayed in surveillance studies.

Bacterial Typing Techniques↗

PubMed2000

Participation of tyrosine phosphorylation in cytoskeletal reorganization, alpha(IIb)beta(3) integrin receptor activation, and aspirin-insensitive mechanisms of thrombin-stimulated human platelets.

BACKGROUND: Fibrinogen binding to the active conformation of the alpha(IIb)beta(3) integrin receptor (glycoprotein IIb/IIIa) and cytoskeletal reorganization are important events in platelet function. Tyrosine phosphorylation of platelet proteins plays an essential role in platelet signal transduction pathways. We studied the participation of tyrosine kinases on these aspects of platelet reactivity and their importance in cyclooxygenase (COX)-1-independent mechanisms in thrombin-stimulated human platelets. METHODS AND RESULTS: Using washed platelets from normal donors and tyrphostin-A47 and aspirin as tyrosine kinase and COX-1 inhibitors, respectively, we found that tyrphostin-A47 downregulated (1) the thrombin-activated conformational change of alpha(IIb)beta(3), (2) actin polymerization and cytoskeletal reorganization, and (3) the quantity of tyrosine-phospho-rylated proteins associated with the reorganized cytoskeleton. The latter are important components of multimolecular signaling complexes. Concomitantly, platelet aggregation and secretion were significantly reduced. Aspirin did not affect receptor activation or tyrosine phosphorylation but did decrease the initial (30-second) burst of actin polymerization. Importantly, aspirin significantly amplified the inhibitory effect of tyrphostin-A47 on all aspects of platelet reactivity that we evaluated. CONCLUSIONS: Tyrosine protein phosphorylation is a regulatory control system of the inside-out mechanism of alpha(IIb)beta(3) activation and cytoskeletal assembly in thrombin-stimulated human platelets. Inhibition of these aspects of platelet function with tyrphostin-A47 is amplified when platelets are treated with aspirin. Therefore, tyrosine phosphorylation is a major component of early signaling events and of COX-1-independent mechanisms of thrombin-induced platelet reactivity. The study results may indicate a novel target for therapeutic intervention.

Aspirin↗

PubMed1999

Risk factors for developing pneumonia within 48 hours of intubation.

Two hundred fifty intubated patients were followed during the first 48 h after intubation in order to identify potential risk factors for developing pneumonia within this period. Thirty-two developed pneumonia during this time. Univariate analysis established that large volume aspiration, presence of sedation, intubation caused by respiratory/cardiac arrest or decrease in the level of consciousness, emergency procedure, cardiopulmonary resuscitation (CPR), and Glasgow coma score < 9 were significantly associated with pneumonia. In contrast, prior infection and prior antimicrobial use were associated with a protective effect. Presence of subglottic secretion drainage and 15 other variables had no significant effect. Multivariate analysis selected CPR (odds ratio [OR] = 5.13, 95% confidence intervals [CI] = 2.14, 12.26) and continuous sedation (OR = 4.40, 95% CI = 1.83, 10.59) as significant risk factors for pneumonia, while antibiotic use (OR = 0.29, 95% CI = 0.12, 0.69) showed a protective effect. Our findings emphasize that risk factors for pneumonia change during the intubation period, and preventing pneumonia requires a combined approach.

Bacterial Infections↗

PubMed1998

Recurrent hydrochlorothiazide-induced pulmonary edema.

Hydrochlorothiazide-induced pulmonary edema is an unusual but life-threatening adverse reaction. It causes hypoxemia, hypotension, tachycardia, fever, and occasionally electrocardiographic and echocardiographic abnormalities. The mechanism of production is, probably, idiosyncratic.

Aged↗

PubMed1997

Hemodynamic and gas exchange responses to inhalation of nitric oxide in patients with the acute respiratory distress syndrome and in hypoxemic patients with chronic obstructive pulmonary disease.

OBJECTIVE: Inhalation of nitric oxide (NO) can improve oxygenation and decrease mean pulmonary artery pressure (MPAP) in patients with the acute respiratory distress syndrome (ARDS). It is not known whether inhaled NO exerts a similar effect in hypoxemic patients with chronic obstructive pulmonary disease (COPD). DESIGN: Prospective clinical study. SETTING: General intensive care unit in Sabadell, Spain. PATIENTS: Nine mechanically ventilated COPD patients (mean age 72 +/- 2 years; forced expiratory volume in 1 s 0.91 +/- 0.11 l) and nine ARDS patients (mean age 57 +/- 6 years; mean lung injury score 2.8 +/- 0.1). MEASUREMENTS AND RESULTS: We measured hemodynamic and gas exchange parameters before NO inhalation (basal 1), during inhalation of 10 ppm NO (NO-10), and 20 min after NO was discontinued (in basal 2) in the ARDS group. In the COPD group, these parameters were measured before NO inhalation (basal 1), during different doses of inhaled NO (10, 20, and 30 ppm), and 20 min after NO was discontinued (basal 2). A positive response to NO was defined as a 20% increment in basal arterial partial pressure of oxygen (PaO2). MPAP and pulmonary vascular resistance (PVR) decreased significantly, while other hemodynamic parameters remained unchanged after NO-10 in both groups. Basal oxygenation was higher in the COPD group (PaO2/FIO2 (fractional inspired oxygen) 190 +/- 18 mmHg) than in the ARDS group (PaO2/FIO2 98 +/- 12 mmHg), (p < 0.01). After NO-10, PaO2/FIO2 increased (to 141 +/- 17 mmHg, p < 0.01) and Qva/Qt decreased (39 +/- 3 to 34 +/- 3%, p < 0.01) in the ARDS group. There were no changes in PaO2/FIO2 and Qva/Qt when the NO concentration was increased to 30 ppm in the COPD group. In both groups, a correlation was found between basal MPAP and basal PVR, and between the NO-induced decrease in MPAP and in PVR. The NO-induced increase in PaO2/FIO2 was not correlated with basal PaO2/FIO2. In the ARDS group, six of the nine patients (66%) responded to NO and in the COPD group, two of nine (22%) (p = 0.05). CONCLUSIONS: NO inhalation had similar effects on hemodynamics but not on gas exchange in ARDS and COPD patients, and this response probably depends on the underlying disease.

Administration, Inhalation↗

PubMed1997

Specific problems of arterial, Swan-Ganz, and hemodialysis catheters.

In our experience, the incidence and pathogenesis of colonization may vary in different types of catheters. Arterial, Swan-Ganz, and hemodialysis catheters are good examples of this problem. This observation has implications for diagnosis, and the best method for each type of catheter may not be the same. In our opinion, laboratory diagnosis in daily practice should be limited to external surface cultures of the tip of intravascular catheters. Intraluminal cultures should be limited to research purposes, except in catheters used for parenteral nutrition or hemodialysis. In this case, the intradermal segment gives more sensitive information. Sensitivity in diagnosing pulmonary artery colonization can be improved by evaluating both the tip and intradermal segments. In presence of an indwelling introducer the intradermal segment should be replaced by the introducer tip.

Catheterization, Peripheral↗

PubMed1997

Nosocomial bacteremia in critically ill patients: a multicenter study evaluating epidemiology and prognosis. Spanish Collaborative Group for Infections in Intensive Care Units of Sociedad Espanola de Medicina Intensiva y Unidades Coronarias (SEMIUC).

A total of 590 consecutive episodes of nosocomial bacteremia were prospectively followed in 30 intensive care units (ICUs) over a 9-month period. The crude and directly related mortality rates were 41.6% and 19%, respectively. The predominant pathogens were coagulase-negative staphylococci (24.4%) and coagulase-positive staphylococci (17.5%). The most frequent sources of infection were intravenous catheters (37.1%). Multivariate analysis defined seven variables as independently influencing crude mortality: adult respiratory distress syndrome (ARDS), septic shock, multiorgan failure (MOF), mechanical ventilation, chronic hepatic failure, acute renal failure, and APACHE II score of > or = 15 at diagnosis. Variables associated with a higher directly related mortality were septic shock, ARDS, acute renal failure, MOF, gram-negative or candidal bacteremia, source of bacteremia other than intravascular catheter, and severe sepsis. We conclude that preventing catheter colonization is crucial in reducing the incidence of bacteremia in an ICU, while improving outcome depends on better management of septic shock and associated complications.

Adult↗

PubMed1997

Survival in patients with nosocomial pneumonia: impact of the severity of illness and the etiologic agent.

OBJECTIVE: To assess the impact of severity of illness at different times, using the Mortality Probability Models (MPM II), and the impact of etiologic agent on survival in patients with nosocomial pneumonia. DESIGN: Retrospective, observational study. SETTING: Fourteen-bed medical-surgical intensive care unit (ICU) in a teaching hospital. PATIENTS: Sixty-two patients with nosocomial pneumonia who were receiving early appropriate antibiotic treatment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Severity of illness at the time of admission to the ICU (M0), 24 hrs after admission (M24), and at the time of pneumonia diagnosis (M1) was determined using MPM II. Bacteriology was established by quantitative cultures from bronchoscopic samples. The outcome measure was the crude mortality rate. The crude mortality rate in the ICU was 59.7%, compared with average predicted mortality rates of 43.5% (M0), 36.4% (M24), and 52.2% (M1). We observed significant differences in mean MPM II determinations between survivors and nonsurvivors at M1 (39.3% vs. 60.9%, p = .001) but not at M0 and M24. In the univariate analysis, the variables most predictive of mortality were the presence of coma (p = .02), inotropic medication use (p = .001), and an MPM II determination of > 50% (p = .001) when pneumonia was diagnosed (M1). Multivariate analysis showed that, in the absence of Pseudomonas aeruginosa, an MPM II determination of > 50% at M1 was associated with a relative risk of death of 4.8. The presence of P. aeruginosa was associated with an increase in the risk of death of 2.6 and 6.36 in both populations with MPM II determinations at M1 of < or = 50% and > 50%, respectively. CONCLUSIONS: Severity of illness when pneumonia is diagnosed is the most important predictor of survival, and this determination should be used for therapeutic and prognostic stratification. In addition, the presence of P. aeruginosa contributed to an excess of mortality that could not be measured by MPM II alone, suggesting the importance of the pathogen in prognosis.

Aged↗

PubMed1997

New perspectives in the diagnosis of nosocomial pneumonia.

In the past decade, much has been learned about the diagnosis of nosocomial pneumonia. Most of these reports focused on evaluating the diagnostic reliability of different techniques and identifying an adequate gold standard. In the past year, the most outstanding studies focused on practical issues such as developing more rapid and less invasive diagnostic techniques and tools, simplifying previously standardized techniques, and searching for safer and more cost-effective procedures. Following the current trend, in the next few years we should spend more time learning about the impact of current techniques on outcome and less time looking for "El Dorado."

Cross Infection↗

PubMed1997

Risk factors for infection by Acinetobacter baumannii in intubated patients with nosocomial pneumonia.

STUDY OBJECTIVE: To investigate the epidemiology of infection by Acinetobacter baumannii in patients with ventilator-associated pneumonia (VAP). DESIGN: Prospective clinical study. SETTING: Three medical-surgical ICUs in teaching hospitals. PATIENTS: We followed up 707 mechanically ventilated patients and 148 episodes of VAP with etiologic diagnosis. RESULTS: A baumannii was isolated in 12 (8.1%) episodes in 148 patients. Five of these episodes were directly responsible for death. Using logistic regression analysis, the risk of VAP due to A baumannii was found to be high in patients with neurosurgery (odds ratio [OR]=10.03; 95% confidence interval [CI]=1.55 to 64.90), ARDS (OR=9.73; 95% CI=1.60 to 59.24), head trauma (OR=5.17; 95% CI=0.88 to 30.34), and large-volume pulmonary aspiration (OR=2.90; 95% CI=0.80 to 10.53). CONCLUSIONS: Intubated patients who develop pneumonia and have any of the above factors are at an increased risk of Acinetobacter infection.

Acinetobacter↗

PubMed1997

Modulatory effect of erythrocytes on the platelet reactivity to collagen in IDDM patients.

Platelets participate in the atherothrombotic complications of diabetes. Recent data demonstrate that platelet reactivity can be modulated via cell-cell interactions with erythrocytes and neutrophils. In this study, platelet reactivity was evaluated in 30 IDDM patients. We used an analytical procedure that permits an independent evaluation of platelet activation (granule release, eicosanoid formation) and platelet recruitment (pro-aggregatory activity of cell-free releasates) after platelet stimulation with collagen in the presence or absence of other blood cells. The interaction between platelets and erythrocytes (hematocrit 40%) resulted in a marked enhancement of platelet activation (5HT, betaTG, TXA2 release) and recruitment in both patients and control subjects. The erythrocyte enhancement of platelet TXA2 synthesis and recruitment was significantly higher in the patients, while no differences were detected in platelet granule release. The elevated platelet recruitment in the IDDM patients was found to be due to 1) increased susceptibility of diabetic platelets to the prothrombotic effect of erythrocytes and 2) the greater response of diabetic platelets to their own cell-free releasate. Patients with poor metabolic control (elevated HbA1c) or longer evolution time had an even greater platelet recruitment. The presence of microalbuminuria is not related to the platelet recruitment. Since platelet recruitment is an essential step in thrombus growth, its enhancement may favor thrombotic complications in IDDM.

Adolescent↗

PubMed1997

[Bacteremias in intensive care].

Critical patients are exposed to monitorization and treatment systems which, in addition to the defense mechanism alterations which accompany their basic disease, favor their acquisition of nosocomial infections. Bacteremia's, along with respiratory infections, are the main nosocomial infections seen in Intensive Care Units (ICU's). Between 20 and 30% of the nosocomial bacteremia's occur in ICU's, which represents an incidence rate which varies from 2.5 to 6.7 episodes per 100 admissions, with these occasionally being epidemic type infections. The main origins are intravascular catheters, and respiratory infections, and in 50% of the cases, Gram positive organisms are responsible. The Gram negative bacteremia group is dominated by Pseudomonas spp., and by other non-fermenting Gram negative bacteria. Also, the incidence of candidemia is higher than in case acquired in conventional hospitalization units. The global mortality is set between 30 and 40%, although the mortality directly associated with infection is close to 70%, which confirms the importance of the underlying diseases in the final prognosis of nosocomial infections in critical patients.

Bacteremia↗

PubMed1996

A specific chromophoric substrate for activity assays of 1,3-1,4-beta-D-glucan 4-glucanohydrolases.

The synthesis of 4-methylumbelliferyl 3-beta-O-cellobiosyl-beta-D-glucopyranoside (3a) and its use as specific substrate to monitor enzyme activity of 1,3-1,4-beta-D-glucan 4-glucanohydrolases are described. The chromophoric substrate 3a is prepared by a chemoenzymatic approach starting from barley grain, whose beta-D-glucan polysaccharide is degraded down to a tri- and tetrasaccharide by an extracellular extract of recombinant E. coli expressing and secreting Bacillus licheniformis 1,3-1,4-beta-glucanase. The trisaccharide 1 is further chemically transformed into the title compound. Its use as substrate for an enzyme activity assay, the specificity of cleavage, and kinetic parameters are reported. As it undergoes a single glycosidic bond hydrolysis with release of 4-methylumbelliferone, direct UV monitoring of the reaction provides a sensitive kinetic assay of the enzyme action.

Biotechnology↗

PubMed1996

Impact of using an indwelling introducer on diagnosis of Swan-Ganz pulmonary artery catheter colonization.

A prospective study was conducted to determine how the use of an indwelling introducer influences the diagnosis of pulmonary artery catheter (PAC) colonization. Sixty-six consecutive PACs and introducers were aseptically removed over a 15-month period. Two segments of the catheter and the catheter tip (a proximal segment from the portion of the catheter beneath the introducer) and two segments of the introducer (a proximal intradermal segment and the introducer tip) were cultured using a semiquantitative technique. Nineteen of 66 (28.7%) PACs showed colonization, representing an incidence of 5.6 episodes per 100 catheterization-days. Catheter tip cultures identified only 68% of colonized PACs; this yield rose to 91% when introducer tip cultures were added. These results indicate a need to evaluate both introducer tip cultures and catheter tip cultures for an accurate diagnosis of PAC colonization when an indwelling introducer is used.

Bacteria↗

PubMed1996

Clinical consequences of the implementation of a weaning protocol.

OBJECTIVE: To analyze the clinical and economic consequences of the implementation of a weaning protocol in patients mechanically ventilated (MV) for more than 48 h. DESIGN: Comparative study. SETTING: General intensive care unit (ICU) in a county hospital covering 360000 inhabitants. PATIENTS: 51 patients weaned by a fixed protocol were studied prospectively and compared with 50 retrospective controls. MEASUREMENTS: The following variables were assessed: Acute Physiology and Chronic Health Evaluation (APACHE) II score, age, cause of respiratory failure, type of extubation (direct extubation or extubation using a weaning technique), number of days on MV before the weaning trial, weaning time, total duration of MV, complications (reintubations and tracheostomies), length of ICU stay, and mortality. RESULTS: The groups were comparable in terms of age, APACHE II score, and main cause of acute respiratory failure. Number of days on MV up to the weaning trial were similar in the two groups (8.4 +/- 7.7 in the protocol group vs 7.5 +/- 5.5 in the control group, NS). Most of the patients (80%) in the protocol group were directly extubated without a weaning technique, unlike the control group (10%) (p < 0.01). When a weaning technique was used, the weaning time was similar in both groups (3.5 +/- 3.9 days vs 3.6 +/- 2.2 days in the control group). Duration of MV was shorter in the protocol group (10.4 +/- 11.6 days) than in the control group (14.4 +/- 10.3 days) (p < 0.05). As a result, the ICU stay was reduced by using the weaning protocol (16.7 +/- 16.5 days vs 20.3 +/- 13.2 days in the control group, p < 0.05). We found no differences in reintubation rate (17 vs 14% in the control group) and need for tracheostomies (2 vs 8% in the control group). CONCLUSION: The implementation of a weaning protocol decreased the duration of MV and ICU stay by increasing the number of safe, direct extubations.

APACHE↗

PubMed1996

Comparative assessment of the anaesthetic and analgesic effects of intramuscular and epidural clonidine in humans.

PURPOSE: The aim of the study was to assess and compare in analogous controlled experimental conditions, the anaesthetic sparing and analgesic effects of the same dose of clonidine administered by the intramuscular (im) and epidural (ep) routes. METHODS: We used a randomized, double blind and placebo controlled protocol. Sixty patients undergoing abdominal hysterectomy were distributed into three groups who, 30 min before surgical incision, received: 300 micrograms ep clonidine plus im saline; ep saline plus 300 micrograms im clonidine; or ep and im saline (ss). General anaesthesia was maintained with 60% N2O in O2, and isoflurane administered at concentrations to maintain mean arterial pressure (MAP) and heart rate (HR) within 20% of basal values. Isoflurane requirements (mass spectrometry), cardiovascular variables (MAP, HR), and plasma concentrations of glucose, cortisol and prolactin were evaluated at critical time points. In the recovery room (RR), sedation (Ramsay) and pain intensity (VAS) were estimated at the time of analgesia request (TAR). RESULTS: Intramuscular and ep clonidine decreased isoflurane requirements similarly by about 85% (P < 0.001). Patients in the ep group had lower MAP (P < 0.03) and HR (P < 0.001) than in the im group, but im and ep clonidine similarly blunted the plasma prolactin increase induced by intubation. In RR, ep but not im clonidine (P < 0.01) induced postoperative analgesia demonstrated by a prolonged TAR 80.8 +/- 7.3 (ep) 35.9 +/- 3.2 (im) and 44.5 +/- 5.1 (ss) min and a lower VAS (P < 0.05). CONCLUSIONS: Epidural and intramuscular clonidine decreased isoflurane requirements similarly, but only the epidural route provided postoperative analgesia, suggesting a spinal site for the analgesic action.

Adult↗

PubMed1996

Antimicrobial use in patients with positive intravascular catheter cultures: a six-month prospective survey in a teaching hospital.

Review of medical records revealed that, of 190 intravascular catheters sent for culture during the study period, 50 were positive. Of these 50, 11 (22%) were sent for culture as a routine procedure without special clinical indications. Of the remaining 39 cultures, only 11 (28%) had clinical impact in the patient's management. Ten of the 50 therapeutic interventions were inappropriate. Restricting cultures to patients who may have catheter-related infection is likely to lead to significant cost savings.

Anti-Bacterial Agents↗