Carmen Hernandez

Histopathologic and Microbiologic Aspects of Ventilator-associated Pneumonia

BackgroundThe relationship between microbiology and histology in patients with ventilator-associated pneumonia has been sparsely described.MethodsTwenty-five patients who died in the intensive care unit after their lungs had been mechanically ventilated for 72 h were studied. Twenty of the 25 died w

Effect of Nasogastric Tube Size on Gastroesophageal Reflux and Microaspiration in Intubated Patients

Gastroesophageal reflux of bacteriologically contaminated gastric contents and subsequent microaspiration of these contents to the lower airways may increase the risk for nosocomial pneumonia (1). The nasogastric tube in ventilated patients is partially responsible for reflux (2) and has been recognized as a risk factor for nosocomial pneumonia (3, 4). Impairment of closure of the lower esophageal sphincter secondary to the nasogastric tube has been suggested as a major contributing factor in gastroesophageal reflux (5). Reducing the bore size of the nasogastric tube may therefore be an appropriate prophylactic measure for both reflux and pneumonia (6). However, because of insufficient evidence, the use of small-bore tubes for prevention of nosocomial pneumonia has not yet been recommended by the Centers for Disease Control and Prevention (7). We compared gastroesophageal reflux and microaspiration of gastric contents to the lower airways in patients intubated with a conventional large-bore nasogastric tube or a small-bore tube. Methods Patients Intubated patients in an intensive care unit for more than 72 hours who were clinically stable were consecutively chosen. Exclusion criteria were previous abdominal surgery, documented macroscopic gastroesophageal reflux or aspiration, paralytic ileum, gastrointestinal bleeding, or severe hemodynamic impairment. Study Design Our study was a randomized, two-period crossover trial. Patients were randomly assigned to receive a small-bore (2.85-mm) nasogastric tube (Flexiflo, Ross Laboratories, Columbus, Ohio) or a large-bore (6.0-mm) nasogastric tube (Salem Sump, Sherwood Medical, Tullamore, Ireland); tubes were inserted 24 hours before the study began. The position of the tube was confirmed by auscultation and abdominal radiography. All measurements were repeated 72 hours after the first measurements were taken with the alternate size of nasogastric tube. All patients were studied in the semirecumbent position (45). Therapy with all medications and enteral feeding through the nasogastric tubes were stopped 12 hours before each study period. The protocol was approved by the ethics committee of our institution, and written informed consent was obtained from each patients next of kin. Measurement of Radioactivity Thirty-seven MBq (1 mL) of colloidal radioactive technetium (99mTc-Re) sulfide (TCK-1, CIS Bio International, Gif-sur-Yvette, France), a nonabsorbable radiopharmaceutical agent, was instilled through the nasogastric tube (8). Samples of serum, gastric juice, and pharyngeal and tracheal secretions were obtained before the first dose was administered and 1, 2, 3, 4, 5, and 17 hours after the first dose was administered. We took measurements 2 and 4 hours after giving the first dose of 99mTc-Re sulfide and then administered additional doses. Radioactive counting was done by using a camera (Packard 800c, Downers Grove, Illinois). Results were corrected for decay and are expressed as a decimal logarithm of counts per minute per mL (cpm [log10]). Statistical Analysis Radioactive counting in all samples (reported as the mean [SE]) was examined by one-way analysis of variance for repeated measurements. We calculated the significance of the time course and of the difference from baseline of any time point during follow-up. We used paired Student t-tests to compare mean and cumulative counts during the 17 hours that elapsed between changes in type of nasogastric tube. Gastroesophageal reflux was assumed when radioactive counts in pharyngeal aspirates increased by one log10 unit compared with baseline at any time point during follow-up. Aspiration was defined accordingly as an increase of more than one log10 unit in radioactive counts in tracheal aspirates. Frequencies of reflux and aspiration were compared by using the chi-square test or the Fisher exact test (if adequate). All data were processed with SPSS for Windows (SPSS, Inc., Chicago, Illinois), and the level of significance was set to 0.05 (all tests were two-tailed). Role of the Funding Sources The funding sources had no role in the collection, analysis, or interpretation of the data or in the decision to submit the paper for publication. Results Patient Data Seventeen patients (mean age [SD], 64 17 years; 15 men, 2 women) were included in the study. Data were not evaluable in 1 of the 17 patients (6%) because no samples were available before administration of the first dose of 99mTc-Re sulfide on either study day. Data in another patient (1 of 17 [6%]) were evaluable on only 1 day. The mean Simplified Acute Physiology State-II score for all patients upon admission to the intensive care unit was 35 15. Reasons for admission to the intensive care unit were acute respiratory failure (9 of 17 patients [53%]), neurologic disease (3 of 17 patients [18%]), cranial trauma (2 of 17 patients [12%]), cardiac arrest (2 of 17 patients [12%]), and coma (1 of 17 patients [6%]). Three patients (3 of 17 [18%]) died in the intensive care unit. Mean Absolute Radioactive Count The time course of the radioactive count was significant in pharyngeal aspirates (P=0.004) and gastric juice (P<0.001) for the two types of nasogastric tube. The radioactive count in pharyngeal aspirates was significantly greater than the baseline count at any time point during follow-up (P=0.005 1 hour after the first dose of 99mTc-Re sulfide; P<0.001 2 hours after the first dose of 99mTc-Re sulfide to 17 hours after the first dose). Accordingly, radioactive counts in gastric juice were also significantly greater than baseline counts during the entire follow-up (P<0.001). The time course was not significant in tracheal aspirates (P>0.2) or serum (P=0.067) for the two types of nasogastric tube. Mean radioactive counts did not differ between the two nasogastric tubes for any type of sample at any time point (Figure 1). Figure 1. Scintigraphic radioactivity counts (mean cpm [log ] SE) of pharyngeal aspirates ( top left ), tracheal aspirates ( top right ), gastric aspirates ( bottom left ), and serum ( bottom right ). Mean Cumulative Counts For both types of nasogastric tubes, the cumulative counts taken 17 hours after the first dose of 99mTc-Re sulfide were significantly greater than baseline counts in pharyngeal secretions (3.2 0.4 compared with 0.9 0.3; difference, 2.3 [95% CI, 1.3 to 3.3; P=0.001]). However, cumulative counts were not greater in tracheal aspirates (1.7 0.3 compared with 0.8 0.3; difference, 0.9 [CI, 0.3 to 2.1; P=0.197]) (Figure 2). We did not find significant differences between the small-bore and large-bore nasogastric tubes 17 hours after the first dose of 99mTc-Re sulfide when comparing the cumulative counts in samples from the pharynx (3.1 0.4 compared with 3.3 0.3; difference, 0.3 [CI, 1.6 to 1.0; P>0.2] or trachea (1.7 0.3 compared with 1.8 0.3; difference, 0.1 [CI, 1.4 to 1.1; P>0.2]. Figure 2. Scintigraphic 17-hour cumulative radioactive counts (mean cpm [log ] SE) of pharyngeal aspirates ( left ) and tracheal aspirates ( right ). Individual Data for Gastroesophageal Reflux and Aspiration Gastroesophageal reflux occurred in 23 of 31 evaluable studies (74%); aspiration occurred in 8 of these 31 studies (26%). Small-bore and large-bore nasogastric tubes did not differ significantly with respect to frequencies of reflux (10 of 15 patients [67%] compared with 13 of 16 patients [81%]; difference, 14 percentage points [CI, 16.6 to 44.6 percentage points; P>0.2]) or aspiration (3 of 15 patients [20%] compared with 5 of 16 patients [31%]; difference, 11 percentage points [CI, 19.4 to 41.4 percentage points; P>0.2]). A trend toward greater frequency of aspiration was seen in studies with reflux compared with studies without reflux (8 of 23 [35%] compared with 0 of 8 [0%]; difference, 35 percentage points [CI, 15.5 to 54.5 percentage points; P=0.076]. Aspiration did not occur in studies without reflux. Discussion In our study, gastroesophageal reflux and microaspiration of gastric contents to the lower airways were not influenced by the size of the nasogastric tube. Two previous studies (8, 10) that used the same isotope technique showed that gastroesophageal reflux is common in mechanically ventilated patients. The potential mechanisms that contribute to reflux in these patients are functional derangement of the upper esophageal sphincter caused by the pressure of the endotracheal tube cuff (8); use of drugs that impair esophageal motility, such as sedatives, curarizing agents, and adrenergic agonists (10); and use of nasogastric intubation that impairs function of the lower esophageal sphincter (2, 5). Despite the controversy about the role of the gastric reservoir in colonization of the oropharynx with abnormal flora (11, 12), microaspiration of contaminated gastric contents to the lower airways seems to play a role in the etiopathogenesis of nosocomial pneumonia (13-17). The prevention of gastroesophageal reflux may therefore be relevant to the prevention of nosocomial pneumonia. Previous studies (8, 9) have shown that the semirecumbent position may reduce gastroesophageal reflux. In these studies, all patients were intubated with a large-bore tube; therefore, the influence of the bore of the nasogastric tube on reflux could not be studied. Ibaez and coworkers (2) found that presence or absence of a nasogastric tube was a key factor for reflux in intubated and mechanically ventilated patients. Use of a nasogastric tube cannot always be avoided. Reducing the size of the tube, however, may improve the closure of the lower esophageal sphincter and thus prevent or reduce gastroesophageal reflux. The effects of the size of the nasogastric tube on gastroesophageal reflux have been investigated in healthy volunteers (18); no differences were seen among participants with no nasogastric tube, participants with a small-bore tube, and participants with a large-bore tube. Accordingly, we did not find any significant differences in gastroesophageal refl

Stomach as a source of colonization of the respiratory tract during mechanical ventilation: association with ventilator-associated pneumonia

The aetiopathogenesis of ventilator-associated pneumonia (VAP) requires abnormal oropharyngeal and gastric colonization and the further aspiration of their contents to the lower airways. VAP develops easily if aspiration or inoculation of microorganisms occur in patients with artificial airways, in whom mechanical, cellular and/or humoral defences are altered. Well-known risk factors for gastric colonization include: alterations in gastric juice secretion; alkalinization of gastric contents; administration of enteral nutrition; and the presence of bilirubin. However, the role of the colonized gastric reservoir in the development of VAP remains debatable. Evidence in favour of the role of the stomach in the development of VAP comes mainly from randomized, controlled trials of selective gut decontamination and stress ulcer prophylaxis in the intensive care unit (ICU), in which reducing the bacterial burden of the stomach decreases the incidence of nosocomial respiratory infections. However, at least three studies of flora have found an absence of stomach origin of pneumonia occurring during mechanical ventilation. Prophylactic measures suggested to prevent VAP in relation to the gastric reservoir include: treatment for stress ulcers with sucralfate; prevention of duodenal reflux with metoclopramide; reduction of gastric burden and bacterial translocation by selective digestive decontamination; acidification of enteral feeding; and jejunal feeding. Gastro-oesophageal reflux can be prevented by using small bore nasogastric tubes and jejunal feeding. The aspiration of gastric contents can be reduced by positioning patients in a semirecumbent position, checking the patency of the tube cuff, and aspiration of subglottic secretions. The role of the stomach as a reservoir for microorganisms causing ventilator-associated pneumonia is still controversial but despite the debate, there is major evidence in the literature in favour of the gastric origin of part of these pulmonary infections.

Effects of Weight Loss after Bariatric Surgery for Morbid Obesity on Vascular Endothelial Growth Factor-A, Adipocytokines, and Insulin

BACKGROUND Adipocytes regulate blood vessel formation, and in turn endothelial cells promote preadipocyte differentiation through the expression of proangiogenic factors, such as vascular endothelial growth factor (VEGF)-A. Some adipocytokines and hormones also have an effect on vascular development. OBJECTIVES Our objectives were to analyze the relationship between weight and circulating VEGF-A in morbidly obese subjects before and after bariatric surgery, and investigate the relationship between circulating VEGF-A and certain adipocytokines and hormones regulating adipocytes. METHODS A total of 45 morbidly obese women and nine lean females were included in the study. Patients underwent bariatric surgery: vertical banded gastroplasty (n=17), gastric bypass (n=17), and biliopancreatic diversion (n=11). Serum samples for VEGF-A, adiponectin, leptin, ghrelin, and insulin were obtained preoperatively and 9-12 months after surgery. RESULTS Obese patients showed significantly higher VEGF-A levels than controls (306.3+/-170.3 vs. 187.6+/-91.9 pg/ml; P=0.04), decreasing to 246.1+/-160.4 after surgery (P<0.001), with no differences among surgical procedures. In controls there was an inverse correlation between VEGF-A and ghrelin (r=-0.85; P<.01), but not in obese patients. Leptin and insulin concentrations were increased in obese patients, with a significant decrease shown after weight loss with surgery. Conversely, adiponectin concentrations were lower in obese patients, with a significant increase shown after weight loss with surgery. Ghrelin was higher in controls than obese patients, decreasing after gastric bypass and biliopancreatic diversion, but not after vertical banded gastroplasty. CONCLUSION Serum VEGF-A levels are significantly higher in obese patients than in lean controls, decreasing after weight loss with bariatric surgery, behaving similarly to other hormones related to adipose mass like leptin and insulin.

Value of intracellular bacteria detection in the diagnosis of ventilator associated pneumonia.

BACKGROUND: Markers of ventilator associated pneumonia are of interest for confirming the diagnosis and for guiding the initial management of this frequent complication of mechanical ventilation. The detection of intracellular organisms in the polymorphonuclear leucocytes (PMNLs) and/or macrophages of bronchoalveolar lavage (BAL) fluid has been suggested as a specific test for the early indication of an infectious pulmonary process. METHODS: The diagnostic value of detecting intracellular organisms in two types of BAL fluid--protected (P-BAL) and conventional (C-BAL)--in 25 patients who died in one unit was prospectively studied. Immediately after death both P-BAL and C-BAL were performed bilaterally. Through a minithoracotomy on both sides of the chest bilateral bronchoscopically guided open lung biopsy samples were obtained from the same area, and an average of eight open lung blind biopsy samples (not bronchoscopically guided) were taken from each lung for histological examination. BAL fluid was examined for quantitative cultures (threshold 10(4) cfu/ml) and for the presence of intracellular organisms and extracellular organisms, and differential cell counts were also performed. RESULTS: Using the histopathology of the bronchoscopically guided open lung biopsies as the gold standard, detection of intracellular organisms in P-BAL (> or = 5%) and C-BAL (> or = 5%) fluids yielded 75% and 57% positive predictive values, and 83% negative predictive values, respectively. Prior treatment with antibiotics decreased the positive and negative predictive values of intracellular organism detection for both types of BAL fluid. The presence of intracellular organisms was correlated with the quantitative cultures of P-BAL and C-BAL samples. Quantitative cultures from P-BAL fluid were less sensitive (22% versus 45%) and more specific (100% versus 55%) than those from C-BAL samples. The percentage of extracellular organisms and the differential cell count in P-BAL and C-BAL samples could not discriminate between the presence or absence of pneumonia. CONCLUSIONS: The presence of > or = 5% intracellular organisms infecting PMNLs or macrophages in P-BAL or C-BAL fluids is a specific marker of ventilator associated pneumonia.

Resultados de dos programas con intervención domiciliaria dirigidos a pacientes con enfermedad pulmonar obstructiva crónica evolucionada

Fundamento y objetivo: Se estudiaron la viabilidad y los resultados de dos programas dirigidos a la reduccion tanto de la estancia media por paciente como del numero de ingresos en pacientes con enfermedad pulmonar obstructiva cronica (EPOC). Pacientes y metodo: Segun el programa de alta temprana, los pacientes ingresados por agudizacion que cumplian los criterios definidos de alta temprana fueron remitidos a su domicilio y controlados por personal de enfermeria del servicio de neumologia. Se realizaron visitas domiciliarias y se procuro el contacto telefonico directo con los equipos de enfermeria y medico durante 6 semanas. En el programa de prevencion de agudizaciones se incluyo a pacientes con EPOC evolucionada y un minimo de tres ingresos hospitalarios durante el ano precedente. Estos pacientes siguieron un programa formativo y disponian de acceso telefonico directo ilimitado con el equipo, ademas del control mediante visitas domiciliarias. Resultados: En el programa de alta temprana se incluyo a 97 pacientes. La estancia media (DE) hospitalaria fue de 5,4 (1,7) dias, significativamente inferior a la estancia media previamente registrada para pacientes con EPOC agudizada (8,52 dias el ano previo al inicio del programa). La proporcion de reingresos hospitalarios tempranos (primeros 3 meses) fue del 17%. En el programa de prevencion de agudizaciones se incluyo a 23 pacientes. Los ingresos hospitalarios disminuyeron de 5,0 (1,8) a 1,7 (2,4) por ano (p = 0,001). Las consultas al servicio de urgencias sin hospitalizacion disminuyeron de 1,2 (1,6) a 0,4 (1,6) por paciente (p = 0,05). Finalmente, la estancia media hospitalaria descendio de 38 (17) a 16 (20) dias (p = 0,0001). Conclusiones: Una combinacion de utilizacion de recursos hospitalarios y programas sencillos de atencion domiciliaria puede reducir la estancia media y el numero de ingresos hospitalarios de pacientes con EPOC.

Relationship between ventilator-associated pneumonia and intramucosal gastric pHi: a case-control study.

PURPOSE Prior investigations have suggested a clear relationship between nosocomial pneumonia and intramucosal gastric pH (pHi), a probable marker of bacterial translocation. METHODS We studied 33 patients (18 with pneumonia and 15 without) admitted to an intensive care unit and hospitalized longer than 72 hours with the aim of assessing the relationship between nosocomial pneumonia, pHi, and outcome. pHi was estimated at the time of inclusion of patients into the study. Arterial pH (pHa) and bicarbonate and stomach pH and tonometer PtCO2 were also recorded. Values of < 7.32 or delta pHa-pHi of > +0.06 were used to differentiate between normal and low pHi. Quantitative cultures of pharyngeal swabs, gastric lumen, and protected specimen brush from lower airways were also done. RESULTS The mean pHi values were 7.397 +/- 0.105 (range, 7.14 to 7.53) and 7.452 +/- 0.059 (range, 7.37 to 7.56) for patients with and without pneumonia, respectively (P = .073). Five patients, all with pneumonia, had pHi < 7.32. No patients without pneumonia had pHi < 7.32 (P = .04). The mean delta pHa-pHi was 0.04 +/- 0.07 (range, -0.11 to 0.13) and 0.05 +/- 0.09 (range, -0.09 to 0.28; P = .72) for patients with and without pneumonia, respectively. However, there were significant differences when tonometer PtCO2 values of both groups were compared (38.9 +/- 8.3 and 30.6 +/- 4.7 mm Hg, respectively; P = .025). Patients with pneumonia had higher alkaline gastric lumen pH (5.2 +/- 1.0) than those without pneumonia (3.8 +/- 1.4; P = .006). Nonsurvivors (n = 7) had more acidic pHi (7.33 +/- 0.11) than survivors (7.44 +/- 0.06; P = .045). The mean gastric lumen bacterial concentration was 4.14 +/- 1.01 Log10 CFU/mL in patients with pneumonia and 4.28 +/- 1.22 Log10 CFU/mL in patients without pneumonia (P = NS). When patients with and without intramucosal gastric acidosis (pHi < 7.32) were compared, the gastric bacterial burden was 4.42 +/- 0.82 Log10CFU/mL and 4.32 +/- 1.03 Log10 CFU/mL (P = .08), respectively. CONCLUSIONS Most patients with nosocomial pneumonia had no associated intramucosal gastric acidosis. However, low pHi was associated with increased mortality.

Actividad anestésica en Cataluña según las características de los centros sanitarios

Fundamento y objetivo Conocer la actividad anestesica de Cataluna (Espana) en 2003 segun los centros sanitarios. Pacientes y metodo A partir de los datos ANESCAT 2003 estudiamos la actividad anestesica de los centros sanitarios clasificados segun su fuente de financiacion –centros publicos del Institut Catala de la Salut (ICS), centros publicos concertados (XHUP) o privados (CP)–, segun su tamano –sin camas de hospitalizacion, con menos de 250 camas, con 251-500 camas y con mas de 500 camas– y su acreditacion o no para la formacion de medicos residentes (MIR). Resultados Participaron 131 centros (11 del ICS, 47 XHUP y 73 CP; 26 sin camas de hospitalizacion, 78 con menos de 250 camas, 21 con 251-500 camas y 6 con mas de 500 camas), de los cuales 17 impartian MIR. Los porcentajes de anestesias fueron: un 44,3% en XHUP, un 36,7% en CP y un 18,5% en ICS; un 5% en centros sin camas de hospitalizacion, un 42,9% en centros con menos de 250 camas, un 35% en centros con 251-500 camas y un 17,1% en centros con mas de 500 camas, y un 35,5% en los MIR. La edad mediana de los pacientes de los CP, de los centros con menos de 250 camas y los no MIR fue menor. El estado fisico de los pacientes fue peor en ICS,en los centros con mas de 500 camas y en los MIR. Destaco la actividad de urgencias cercana al 25% en XHUP, ICS, centros con mas de 250 camas y en los MIR. La anestesia ambulatoria en los CP supuso el 40% y en los otros, el 31%. La duracion de la anestesia y de la recuperacion postanestesica fue mayor en el ICS, en centros con mas de 500 camas y en los MIR. El ingreso en unidades de cuidados criticos en el postoperatorio y la analgesia especializada fueron superiores en ICS, centros con mas de 500 camas y MIR. Conclusiones La complejidad de la actividad tanto anestesica como quirurgica y la gravedad de los pacientes aumentaron con el numero de camas del hospital y su titularidad publica.

Should remission of type 2 diabetes mellitus be the foremost goal after bariatric surgery

Retrospective study of 125 patients (59.2% women) with preoperative diagnosis of T2D who underwent BS in a single center (2006-2011). Anthropometric and metabolic parameters, before surgery and at one-year follow-up. Definition of T2D remission according to Buse et al: HbA1c<6%, fasting glucose (FG) <100 mg/dL, absence of pharmacologic treatment. Evaluation of metabolic status of non-remitters, according to ADA’s target recommendations of glucose and lipid control: HbA1c < 7%, LDL-c < 100 mg/dL, triglycerides < 150 mg/dL, HDL-c > 40 (male) or > 50 mg/dL (female). Statistics: analysis of variance.

Histopathologic and Microbiologic Aspects of Ventilator-Associated Pneumonia

Background The relationship between microbiology and histology in patients with ventilator-associated pneumonia has been sparsely described. Methods Twenty-five patients who died in the intensive care unit after their lungs had been mechanically ventilated for 72 h were studied. Twenty of the 25 died with clinical suspicion of pulmonary infection. A total of 375 immediate postmortem pulmonary biopsies were obtained after death and processed for quantitative microbiology and histology. Four evolutionary stages of pneumonia were defined: early, intermediate, advanced, and resolution. Results At least one specimen with histologic evidence of pneumonia was found in all but two patients (92%). Histologic pneumonia was a widespread and frequent process (46% of biopsies examined) involving predominantly the lower lobes (55% of all biopsies with pneumonia) and showing different histopathologic stages of progression coexisting in the same lung lobes. Lung cultures were frequently polymicrobial (149 of 375, 40% of the pulmonary biopsy cultures, and 20 of 25, 80% of the cases) and not always yielding the same pathogen (19 microorganisms) when comparing one lung to the other. Histopathology and microbiologic biopsy cultures showed a weak relationship (28% and 49% of species had counts greater or equal to 103 cfu/g in samples without pneumonia from patients with and without prior antibiotic treatment, respectively). Histopathologic evolutionary stages were not associated with any differences in quantitative culture results of pulmonary biopsies, independently of prior administration of antibiotics. Higher bacterial concentrations of biopsy cultures were associated with the absence of prior antibiotic treatment. Conclusions Ventilator-associated pneumonia is a frequent diffuse and polymicrobial process showing different coexisting degrees of evolution and involving preferentially the lower lobes. Microbiology and histology can be dissociated even in the absence of prior antibiotic treatment. Lung histology appears more reliable than bacteriology as a diagnostic reference test.