Luis Castillo

Gut mucosal atrophy after a short enteral fasting period in critically ill patients.

PURPOSEnThe purpose of this study was to evaluate the presence of gut mucosal atrophy and changes in mucosal permeability in critically ill patients after a short fasting period.nnnMATERIALS AND METHODSnFifteen critically ill patients underwent a period of enteral fasting of at least 4 days (mean 7.8 days). We took the following measurements the day before initiating enteral nutrition: indirect calorimetry, serum albumin, prealbumin, and lymphocyte count. We also performed a duodenal endoscopic biopsy with histopathological and mucosal morphometric analysis including villus height and crypt depth. The lactulose-mannitol test was performed to assess gut permeability. A total of 28 healthy volunteers served as controls for duodenal biopsy or lactulose-mannitol test. Clinical data, such as length of fasting, severity score, and previous parenteral nutritional support, were recorded.nnnRESULTSnWe found gut mucosal atrophy, expressed as a decrease in villus height and crypt depth, in patients compared with controls. The patients also exhibited an abnormal lactulose-mannitol test. Morphometric changes did not correlate with permeability. Further, we found no correlation between the results of the lactulose-mannitol test and of mucosal morphometry with clinical data.nnnCONCLUSIONSnWe found that a short period of enteral fasting was associated with significant duodenal mucosal atrophy and abnormal gut permeability in critically ill patients.

Use of methylene blue in patients with refractory septic shock: Impact on hemodynamics and gas exchange

PURPOSEnThe purpose of this study was to assess the acute effects of methylene blue, an inhibitor of nitric oxide synthesis, on hemodynamics and gas exchange in patients with refractory septic shock in a prospective clinical trial at medical and surgical intensive care units in a tertiary university hospital.nnnPATIENTS AND METHODSnProspective, sequential study of 10 consecutive patients admitted with severe septic shock of diverse causes and unable to achieve an adequate arterial pressure despite the use of at least two vasoactive drugs. Six of them also developed acute lung injury. All received 1 mg/kg intravenous bolus of methylene blue. Hemodynamic and respiratory parameters were measured at baseline and at 30, 60, 120, and 180 minutes after the bolus injection.nnnRESULTSnSystolic, diastolic, mean arterial blood pressure, and systemic vascular resistance increased significantly in all patients, whereas no significant changes were observed in cardiac output, oxygen consumption, or oxygen extraction ratio. Gas exchange remained unaffected in patients with acute lung injury.nnnCONCLUSIONSnMethylene blue had an acute vasopressor effect in patients with refractory septic shock, and it was not deleterious on respiratory function.

Lung computed tomography during a lung recruitment maneuver in patients with acute lung injury

ObjectiveTo assess the acute effect of a lung recruitment maneuver (LRM) on lung morphology in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS).PatientsTen patients with ALI/ARDS on mechanical ventilation.DesignProspective clinical study.SettingComputed tomography (CT) scan facility in a teaching hospital.InterventionsAn LRM performed by stepwise increases in positive end-expiratory pressure (PEEP) of up to 30–40xa0cmH2O. Lung basal CT sections were taken at end-expiration (patients 1 to 5), and at end-expiration and end-inspiration (patients 6 to10). Arterial blood gases and static compliance (Cst) were measured before, during and after the LRM.Measurements and main resultsPoorly aerated and non-aerated tissue at PEEP 10xa0cmH2O accounted for 60.0±29.1% of lung parenchyma, while only 1.1±1.8% was hyperinflated. Increasing PEEP to 20 and 30xa0cmH2O, compared to PEEP 10xa0cmH2O, decreased poorly aerated and non-aerated tissue by 16.2±28.0% and 33.4±13.8%, respectively (p<0.05). This was associated with an increase in PaO2 and a decrease in total static compliance. Inspiration increased alveolar recruitment at all PEEP levels. Hyperinflated tissue increased up to 2.9±4.0% with PEEP 30xa0cmH2O, and to a lesser degree with inspiration. No barotrauma or severe hypotension occurred.ConclusionsLung recruitment maneuvers improve oxygenation by expanding collapsed alveoli without inducing too much hyperinflation in ALI/ARDS patients. An LRM during the CT scan gives morphologic and functional information that could be useful in setting ventilatory parameters.

Influence of polymeric enteral nutrition supplemented with different doses of glutamine on gut permeability in critically ill patients

OBJECTIVESnTo evaluate the effect of glutamine-supplemented polymeric enteral formulas on the recovery of gut-permeability abnormalities in critically ill patients.nnnMETHODSnTwenty-three patients were randomized to receive a conventional casein-based enteral formula (ADN), ADN plus glutamine in a dose of 0.15 g x kg(-1) x d(-1) or ADN plus 0.30 g x kg(-1) x d(-1) of glutamine for 8 d. The lactulose mannitol permeability test (L/M) was performed at baseline and at the end of the study. Nineteen healthy volunteers served as controls for the L/M test.nnnRESULTSnAn increase in permeability compared with control subjects was observed in patients at baseline (mean +/- standard error of the mean; L/M ratio: 0.11 +/- 0.03 and 0.025 +/- 0.004, respectively; P < 0.02). The L/M ratio improved after the period of enteral nutrition as a whole (initial L/M: 0.11 +/- 0.03, final L/M: 0.061 +/- 0.01; P < 0.03), but no difference was found between groups.nnnCONCLUSIONSnEven though polymeric enteral nutrition was associated with a significant improvement in the L/M ratio, glutamine supplementation did not show a specific influence in improving recovery of gut permeability in critically ill patients.

Los predictores de satisfacción de pacientes en un centro hospitalario universitario

Background: Client satisfaction is an important indicator of the quality of services, and health care is not an exemption. Aim: To explore and establish the predictors that exert the greater influence on the level of satisfaction with the service offered in a University Hospital. Material and method: The source of the study is a data base, obtained from a survery made to 355 patients of the Hospital Clinico de la Pontificia Universidad Catolica de Chile prior to discharge. A multiple regression analysis was used to determine the relative importance of the different factors in the quality of service. The regression variables were reduced to a number of factors, obtained of Factorial Analysis and a Varimax rotation, allowing them to clarify their relations. Results: After performing the main components analysis, seven factors or dimensions that explained a 69% of the total variance were obtained. The predictive model explains up to 40% of the criterion variable (Global Satisfaction during the hospitalization). The factor with the greatest predictive power was the relationship between the patients and nursing staff. Other factors that emerged as important were communication, medical attention and room conditions. Conclusions: Perceptive type components had the greater relative weight to determine the level of patient satisfaction in this survey (Rev Med Chile 2007; 135: 696-701). (Key words: Delivery of health care; Patients care management; Patient satisfaction)

Effects of positive end-expiratory pressure on gastric mucosal perfusion in acute respiratory distress syndrome

IntroductionPositive end-expiratory pressure (PEEP) improves oxygenation and can prevent ventilator-induced lung injury in patients with acute respiratory distress syndrome (ARDS). Nevertheless, PEEP can also induce detrimental effects by its influence on the cardiovascular system. The purpose of this study was to assess the effects of PEEP on gastric mucosal perfusion while applying a protective ventilatory strategy in patients with ARDS.MethodsEight 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.ResultsPEEP 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.ConclusionPEEP 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.

Severity stratification of septic shock according to noradrenaline requirement

Septic shock (SS) is associated with 50% mortality. Severity is usually estimated from indexes of multiorgan dysfunction, but hemodynamic dysfunction, despite its main role, has traditionally been underscored. The aim of this study was to test a severity classification for SS according to noradrenaline (NA) requirements.

Therapeutic hypothermia as a bridge to transplantation in patients with fulminant hepatic failure.

The most important topics in fulminant hepatic failure are cerebral edema and intracranial hypertension. Among all therapeutic options, systemic induced hypothermia to 33 - 34ºC has been reported to reduce the high pressure and increase the time during which patients can tolerate a graft. This review discusses the indications and adverse effects of hypothermia.

Fluid and Electrolyte Management in Neurosurgical Critical Care

Imbalance and dysregulation of the fluid and electrolyte homeostasis are common and of great concern in patients after insults to the central nervous system. Disturbances may occur as a part of the disease process or they may be iatrogenic. The consequences of fluid and electrolyte derangements are frequently life-threatening and are recognized to determine outcome, particularly if unrecognized or persistently severe.

Lung computed tomography during a lung recruitment maneuver on patients with acute respiratory failure: mechanisms and clinical usefulness

Lung computed tomography (CT) has been widely used to assess lung morphology, which has led us to a better understanding on the pathophysiology of ARDS, mechanical ventilation and ventilatory induced lung injury. Despite the absence of controlled studies and standardization, LRM are increasingly used in patients with acute respiratory failure. The objective of our study was to assess the effect of different levels of airway pressure on lung morphology by performing a LRM during the lung CT-scan. This way, we could set the best ventilatory strategy for the patient and identify the mechanisms involved during the LRM.