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Search Results: 1 - 10 of 9080 matches for " Alejandro Bruhn "
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Effects of positive end-expiratory pressure on gastric mucosal perfusion in acute respiratory distress syndrome
Alejandro Bruhn, Glenn Hernandez, Guillermo Bugedo, Luis Castillo
Critical Care , 2004, DOI: 10.1186/cc2905
Abstract: Eight patients were included. A pressure–volume curve was traced and ideal PEEP, defined as lower inflection point + 2 cmH2O, was determined. Gastric tonometry was measured continuously (Tonocap). After baseline measurements, 10, 15 and 20 cmH2O PEEP and ideal PEEP were applied for 30 min each. By the end of each period, hemodynamic, CO2 gap (gastric minus arterial partial pressures), and ventilatory measurements were performed.PEEP had no effect on CO2 gap (median [range], baseline: 19 [2–30] mmHg; PEEP 10: 19 [0–40] mmHg; PEEP 15: 18 [0–39] mmHg; PEEP 20: 17 [4–39] mmHg; ideal PEEP: 19 [9–39] mmHg; P = 0.18). Cardiac index also remained unchanged (baseline: 4.6 [2.5–6.3] l min-1 m-2; PEEP 10: 4.5 [2.5–6.9] l min-1 m-2; PEEP 15: 4.3 [2–6.8] l min-1 m-2; PEEP 20: 4.7 [2.4–6.2] l min-1 m-2; ideal PEEP: 5.1 [2.1–6.3] l min-1 m-2; P = 0.08). One patient did not complete the protocol because of hypotension.PEEP of 10–20 cmH2O does not affect gastric mucosal perfusion and is hemodynamically well tolerated in most patients with ARDS, including those receiving adrenergic drugs.Recent studies have shown that lung protective strategies using low tidal volumes and high levels of positive end-expiratory pressure (PEEP) reduce mortality and are becoming standard practice in patients with acute respiratory distress syndrome (ARDS) [1,2].Although PEEP improves arterial oxygenation, it can adversely affect systemic hemodynamics, reducing venous return and cardiac output. These effects are proportional to the PEEP level. Regional perfusion can also be affected by PEEP, independently of cardiac output changes. The splanchnic perfusion is particularly sensitive, and any reduction can compromise its barrier function, promote bacterial translocation, and contribute to the development of multiple organ failure [3]. In experimental models, PEEP has markedly decreased mesenteric and portal blood flow, despite only moderate reductions in cardiac output [4-8]. Similar results have been repo
Encuesta sobre humidificación de la vía aérea en unidades de cuidados intensivos de adultos de Chile Airway humidification practices in Chilean intensive care units
Jaime Retamal,Juan Castillo,Guillermo Bugedo,Alejandro Bruhn
Revista médica de Chile , 2012,
Abstract: Background: In patients with an artificial airway, inspired gases can be humidified and heated using a passive (heat and moisture exchange filter - HMEF), or an active system (heated humidifier). Aim: To assess how humidification is carried out and what is the usual clinical practice in this field in Chilean intensive care units (ICUs). Material and Methods: A specific survey to evaluate humidification system features as well as caregivers' preferences regarding humidification systems, was carried out on the same day in all Chilean ICUs. Results: Fifty-five ICUs were contacted and 44 of them completed the survey. From a total of 367 patients, 254 (69%) required humidification because they were breathing through an artificial airway. A heated humidifier was employed only in 12 patients (5%). Forty-three ICUs (98%) used HMEF as their routine humidification system. In 52% of surveyed ICUs, heated humidifiers were not available. Conclusions: In Chile the main method to humidify and heat inspired gases in patients with an artificial airway is the HMEF. Although there are clear indications for the use of heated humidifiers, they are seldom employed.
Lipoperoxidation and Protein Oxidative Damage Exhibit Different Kinetics During Septic Shock
Max Andresen,Tomas Regueira,Alejandro Bruhn,Druso Perez,Pablo Strobel,Alberto Dougnac,Guillermo Marshall,Federico Leighton
Mediators of Inflammation , 2008, DOI: 10.1155/2008/168652
Abstract: Septic shock (SS)-related multiorgan dysfunction has been associated with oxidative damage, but little is known about the temporal damage profile and its relationship to severity. The present work investigated prospectively 21 SS patients. Blood samples were obtained at diagnosis, 24, 72 hours, day 7, and at 3 months. At admission, thiobarbituric acid reactive substances (TBARSs), plasma protein carbonyls, plasma protein methionine sulfoxide (MS), ferric/reducing antioxidant power (FRAP), total red blood cell glutathione (RBCG), uric acid (UA), and bilirrubin levels were increased (<.05). Total radical—trapping antioxidant potential (TRAP) and vitamin-E were similar to controls, and vitamin-C was decreased (<.05). During evolution, TBARS and RBCG increased (<.001), vitamin-E levels remained stable, whereas plasma protein carbonyls and MS, TRAP, vitamin-C, reduced glutathione, and UA levels decreased (<.006). After 3 months, plasma protein carbonyls and MS persisted elevated. More severe patients exhibited higher TBARS, TRAP, FRAP, vitamin-C, UA, and bilirrubin levels. Our results suggest early and persistent oxidative stress during septic shock and a correlation between increasing levels of lipoperoxidation and sepsis severity.
Preliminary study of ventilation with 4 ml/kg tidal volume in acute respiratory distress syndrome: feasibility and effects on cyclic recruitment - derecruitment and hyperinflation
Jaime Retamal, Javiera Libuy, Magdalena Jiménez, Matías Delgado, Cecilia Besa, Guillermo Bugedo, Alejandro Bruhn
Critical Care , 2013, DOI: 10.1186/cc12487
Abstract: Patients with pulmonary acute respiratory distress syndrome (ARDS) were included in a cross-over study with two Vt levels: 6 and 4 ml/kg. The protocol had two parts: one bedside and other at the CT room. To avoid severe hypercapnia in the 4 ml/kg arm, we replaced the heat and moisture exchange filter by a heated humidifier, and respiratory rate was increased to keep minute ventilation constant. Data on lung mechanics and gas exchange were taken at baseline and after 30 minutes at each Vt (bedside). Thereafter, a dynamic CT (4 images/sec for 8 sec) was taken at each Vt at a fix transverse region between the middle and lower third of the lungs. Afterwards, CT images were analyzed and cyclic recruitment-derecruitment was determined as non aerated tissue variation between inspiration and expiration, and hyperinflation as maximal hyperinflated tissue at end-inspiration, expressed as % of lung tissue weight.We analyzed 10 patients. Decreasing Vt from 6 to 4 ml/kg consistently decreased cyclic recruitment-derecruitment from 3.6 (2.5-5.7) % to 2.9 (0.9-4.7) % (p<0.01) and end-inspiratory hyperinflation from 0.7 (0.3 - 2.2) to 0.6 (0.2 - 1.7) % (p=0.01). No patient developed severe respiratory acidosis or severe hypercapnia when decreasing Vt to 4 ml/kg (pH 7.29 (7.21-7.46); PaCO2 48 (26 - 51) mmHg).Decreasing Vt from 6 to 4 ml/kg reduces cyclic recruitment-derecruitment and hyperinflation. Severe respiratory acidosis may be effectively prevented by decreasing instrumental dead space and by increasing respiratory rate.
Sublingual microcirculatory changes during high-volume hemofiltration in hyperdynamic septic shock patients
Carolina Ruiz, Glenn Hernandez, Cristian Godoy, Patricio Downey, Max Andresen, Alejandro Bruhn
Critical Care , 2010, DOI: 10.1186/cc9271
Abstract: This was a prospective, non-randomized study at a 16-bed, medical-surgical intensive care unit of a university hospital. We included 12 severe hyperdynamic septic shock patients (norepinephrine requirements > 0.3 μg/kg/min and cardiac index > 3.0 L/min/m2) who underwent a 12-hour HVHF as a rescue therapy according to a predefined algorithm. Sublingual microcirculation (Microscan for NTSC, Microvision Medical), systemic hemodynamics and perfusion parameters were assessed at baseline, at 12 hours of HVHF, and 6 hours after stopping HVHF.Microcirculatory flow index increased after 12 hours of HVHF and this increase persisted 6 hours after stopping HVHF. A similar trend was observed for the proportion of perfused microvessels. The increase in microcirculatory blood flow was inversely correlated with baseline levels. There was no significant change in microvascular density or heterogeneity during or after HVHF. Mean arterial pressure and systemic vascular resistance increased while lactate levels decreased after the 12-hour HVHF.The use of HVHF as a rescue therapy in patients with severe hyperdynamic septic shock does not deteriorate sublingual microcirculatory blood flow despite the increase in systemic vascular resistance.High-volume hemofiltration (HVHF) is a potential rescue therapy in patients with severe septic shock, and some clinical studies suggest that HVHF can decrease vasopressor requirements and improve lactate clearance [1,2]. Therefore, HVHF may have a place in refractory septic shock by contributing to the stability of systemic hemodynamics and eventually improving systemic perfusion. However, studies supporting HVHF are rather small and non-randomized, and this prevents investigators from drawing a more definitive conclusion about its real impact on clinically relevant outcomes. Indeed, decreases in vasopressor requirements and lactate levels may not necessarily reflect a real improvement in perfusion. In the past, therapies such as steroids and nitric o
Press?o expiratória final positiva aumenta o estiramento em pacientes com LPA/SDRA
Bugedo, Guillermo;Bruhn, Alejandro;Regueira, Tomás;Romero, Carlos;Retamal, Jaime;Hernández, Glenn;
Revista Brasileira de Terapia Intensiva , 2012, DOI: 10.1590/S0103-507X2012000100007
Abstract: objective: the objective of this study was to assess the effects of positive end-expiratory pressure on recruitment, cyclic recruitment and derecruitment and strain in patients with acute lung injury and acute respiratory distress syndrome using lung computed tomography. methods: this is an open, controlled, non-randomized interventional study of ten patients with acute lung injury and acute respiratory distress syndrome. using computed tomography, single, basal slices of the lung were obtained during inspiratory and expiratory pauses at a tidal volume of 6 ml/kg and a positive end-expiratory pressure of 5, 10, 15 and 20 cmh2o. the densities of the lung parenchyma were measured in hounsfield units. the values for positive end-expiratory pressure-induced recruitment, cyclic recruitment and derecruitment and strain were then calculated. results: increasing levels of positive end-expiratory pressure were correlated with increased recruitment and global strain (p < 0.01), which was significantly correlated with plateau pressure (r2 = 0.97, p < 0.01). in addition, increasing levels of positive end-expiratory pressure systematically increased strain along the sternovertebral axis. conclusion: while strain is an adverse effect of positive end-expiratory pressure, the decision use positive end-expiratory pressure with any patient should be balanced against the potential benefits of recruitment. due to the small number of patients in this study, the present data should be treated as hypothesis generating and is not intended to limit the clinical application of a high level of positive end-expiratory pressure in patients with severe hypoxemia.
Evaluación de la microcirculación sublingual en un paciente en shock séptico refractario tratado con hemofiltración de alto volumen
Ruiz B,Carolina; Bruhn C,Alejandro; Hernández P,Glenn; Andresen H,Max;
Revista médica de Chile , 2008, DOI: 10.4067/S0034-98872008000900013
Abstract: microcirculation is severely compromised in sepsis, with a reduction of capillary density and flow impairment. these alterations have important prognostic implications, being more severe in non-survivors to septic shock. today microcirculation may be assessed bedside, non-invasively usingpolarized light videomicroscopy a technique known as sdf (side dark field). we report a 54 year-old man with an extramembranous nephropathy that developed a necrotizing fascitis associated to septic shock, in whom microcirculation was periodically assessed during his management. the patient was treated with buids, vasoactive drugs, antibiotics and was operated for exploration and debridement. as the patient persisted in refractory shock despite treatment, high-volume hemofiltration was started. before hemofiltration the patient had severe microcirculatory alterations that improved during and after the procedure. physiologic endpoints of high-volume hemofiltration in septic shock remain unknown, but it has the capacity to clear in?ammatory mediators. since microcirculatory alterations are in part secondary to these mediators, their removal is beneficia! like other authors, we found no relation between microcirculation and other haemodynamic and perfusión variables.
Ventilación diferencial en el manejo del síndrome de distress respiratorio agudo secundario a mediastinitis necrotizante descendente: Rol de la tomografía axial computarizada dinámica de pulmón Use of dinamic lung computed tomography to orient mechanical ventilation in adult respiratory distress syndrome: Report of one case with acute mediastinitis
Guillermo Bugedo T,Alejandro Bruhn C,Glenn Hernández P,Gonzalo Rojas C
Revista médica de Chile , 2003,
Abstract: Lung computed tomography (CT) is being used increasingly to assess lung morphology in patients on mechanical ventilation. Lung CT under known levels of airway pressure (dynamic CT) can also assess the response of lung parenchyma to ventilatory therapy. We report a patient with acute respiratory distress syndrome secondary to descending necrotizing mediastinitis, in whom lung dynamic CT oriented ventilatory management. Independent lung ventilation improved gas exchange and helped patient recovery (Rev Méd Chile 2003; 131: 200-8)
Cateterización venosa suprahepática en cuatro casos de shock séptico severo: Report of four cases Suprahepatic vein oxygen saturation monitoring and gastric tonometry in the management of severe septic shock
Carlos Inzunza P,Matías Cornu A,Alejandro Bruhn C,Luis Castillo F
Revista médica de Chile , 2001,
Abstract: Splanchnic hypoperfusion, with pathogenic implications for multiple organ failure, can occur during septic shock. We report four patients with septic shock in whom regional hepatosplenic splanchnic perfusion was monitored through suprahepatic vein catheterization and gastric tonometry. Suprahepatic lactate and oxygen saturation showed splanchnic hypoperfusion in all patients. These parameters improved only in the patient that survived. Gastric tonometry was more inconsistent. We conclude that suprahepatic vein catheterization could have a role in the management of septic shock. ( Rev Méd Chile 2001; 129: 552-5)
Evaluación de la microcirculación sublingual en un paciente en shock séptico refractario tratado con hemofiltración de alto volumen Evaluation of sublingual microcirculation in septic shock. Report of one patient treated with high volume hemofiltration
Carolina Ruiz B,Alejandro Bruhn C,Glenn Hernández P,Max Andresen H
Revista médica de Chile , 2008,
Abstract: Microcirculation is severely compromised in sepsis, with a reduction of capillary density and flow impairment. These alterations have important prognostic implications, being more severe in non-survivors to septic shock. Today microcirculation may be assessed bedside, non-invasively usingpolarized light videomicroscopy a technique known as SDF (side dark field). We report a 54 year-old man with an extramembranous nephropathy that developed a necrotizing fascitis associated to septic shock, in whom microcirculation was periodically assessed during his management. The patient was treated with Buids, vasoactive drugs, antibiotics and was operated for exploration and debridement. As the patient persisted in refractory shock despite treatment, high-volume hemofiltration was started. Before hemofiltration the patient had severe microcirculatory alterations that improved during and after the procedure. Physiologic endpoints of high-volume hemofiltration in septic shock remain unknown, but it has the capacity to clear in ammatory mediators. Since microcirculatory alterations are in part secondary to these mediators, their removal is beneficia! Like other authors, we found no relation between microcirculation and other haemodynamic and perfusión variables.
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