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 1 case with acute mediastinitis

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

Falla cardio respiratoria severa tratada con asistencia cardiopulmonar extracorpórea: caso clínico / Treatment of severe respiratory failure with cardiopulmonary extracorporeal assistance

Cardiopulmonary extracorporeal assistance is a high complexity procedure for patients with acute respiratory failure, who have failed conventional ventilatory support. A 30 years old female patient with bacterial endocarditis and congestive cardiac failure subjected to cardiac surgery presented severe hypoxemia, right heart failure and pulmonary hypertension, and failed conventional treatment. Cardiopulmonary support with extracorporeal membrane oxygenation (ECMO) reverted the pathophysiologic alterations allowing a successful recovery

Cateterización venosa suprahepática en cuatro casos de shock séptico severo / Suprahepatic vein oxygen saturation monitoring and gastric tonometry in the management of severe septic shock: report of 4 cases

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

Ventilación con presión positiva no invasiva, VPPNI, en pacientes con insuficiencia respiratoria aguda hipoxémica / Noninvasive ventilation with positive pressure in patients with acute hypoxemic respiratory failure

Quisimos evaluar la aplicabilidad y eficacia de la ventilación con presión positiva no invasiva (VPPNI) en pacientes con insuficiencia respiratoria aguda (IRA) hipoxémica y aumento del trabajo respiratorio. En un periodo de 10 meses evaluamos a 64 pacientes que ingresaron a nuestro servicio con el diagnóstico de IRA y signos de fatiga muscular, en ausencia de patología crónica. Fueron considerados no aptos para VPPNI quienes tuvieran compromiso de conciencia importante, inestabilidad hemodinámica o más de dos órganos en falla, cirugía reciente de esófago, estómago o duodeno, hemorragia digestiva alta activa, distensión abdominal importante o dificultad en el manejo de secreciones. Luego de aplicar los criterios de exclusión, 14 (23 por ciento) pacientes fueron sometidos a VPPNI por un periodo de 1 a 9 días. La Pa/FiO2, sin cambios significativos en la PaCO2 y frecuencia respiratoria. En 5 pacientes (36 por ciento) fracasó el método, de los cuales 2 fallecieron. Un paciente presentó una escara nasal. Por su mínima invasividad y fácil aplicación, la VPPNI debe ser considerada precozmente en todo paciente con IRA hipoxémica con buen nivel de conciencia y que preserve su ventilación espontánea

Uso de anfotericina B en mezcla lipídica: ¿previene la toxicidad de la droga en pacientes críticos? / Use of amphotericin B as lipid emulsion: does it prevent drug toxicity in critical patients?

Background: Amphotericin B is efficacious for the treatment of systemic candidiasis, however it has potentially serious toxic effects. Administration as lipid emulsions has been advocated to decrease its toxicity. Aim: To compare the safety and tolerance of amphotericin B administered as lipid emulsion or dissolved in dextrose in water. Patients and methods: Forty five patients with confirmed or highly suspected systemic candidiasis were studied. Between January 1996 and June 1997 amphotericin B was administered in dextrose in water to 17 patients (group 1). Between July 1997 and December 1998, the drug was delivered in lipid emulsions (Intralipid, group 2). Clinical and laboratory parameters (serum creatinine, urea nitrogen and potassium), were assessed daily. Results: Both treatment groups were clinically comparable and had the same survival. Accumulative amphotericin B dose administered was 343.2 ñ 197 and 414.6 ñ 518 mg respectively. Hypokalemia was more frequent in group 2 (52 and 25 percent respectively, p < 0.05). There were no differences in the outcome of renal function or other adverse reactions. Conclusions: Administration of amphotericin B as lipid emulsions did not reduce its toxicity in critical patients

Síndrome de respuesta inflamatoria sistémica severa: ¿es comparable a la sepsis severa? / Systemic inflammatory response syndrome: is it similar to severe sepsis?

Background: in 1992, a consensus conference defined the terms systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis and septic shock. Since then, numerous reports have validated the prognostic usefulness of these operative definitions. Aim: to evaluate if sepsis severity criteria, as defined by the Consensus Conference, can be applied to noninfectious SIRS. Patients and methods: five hundred eighteen patients admitted to 5 intensive care units (ICU) from 4 hospitals were prospectively evaluated during a 3 months period. Patients that met at least one severity criteria were included. SIRS etiology, organ dysfunction and evolution were recorded in each patient. Results: One hundred two patients were included: 79 with sepsis (group I) and 23 with noninfectious SIRS (group II). ICU and hospital mortality were comparable (43 and 48 percent in sepsis compared to 43 and 51 percent in non infectious SIRS). The most common sources of sepsis were pneumonia and peritonitis. Group II patients had a wide variety of diseases. ICU stay, APACHE score and number of organs with dysfunction were not different among groups. Only the incidence of renal dysfunction was higher in the septic group. Conclusions: The Consensus sepsis severity criteria can be applied to noninfectious SIRS, defining a population subset with similar high mortality and organ dysfunction incidence, although with greatly heterogeneous etiologies

Gradiente transcraneana de citoquinas y permeabilidad intestinal en la injuria cerebral aguda severa / Transcranial cytokine gradient and intestinal permeability in severe brain injury

Background: Acute brain injury is associated with a bimodal hypermetabolic state probably caused by cytokine secretion and high hormone and catecholamine concentrations. In a first stage, the brain would produce these substances and afterwards, another production source, most probably the splanchnic territory, would perpetuate the hypermetabolic state. Aim: To investigate the cytokine production source and to assess intestinal permeability in acute brain injury in the absence of cerebral ischemia and systemic oxygen deficit. Patients and methods: Arterial systemic and cerebral venous bulbar interleukin 1 õ and interleukin 6 levels were measured during the first seven days of evolution in 15 patients with acute brain injury. Serum lactate, the oxygen/lactate ratio, gastric intramucosal pH and intestinal permeability using the lactulose/mannitol test were also assessed in the same period. Results: High arterial and venous interleukin 1 õ and interleukin 6 levels were detected. A positive gradient for interleukin 6 levels was detected throughout the study period with normal intramucosal pH, lactate and oxygen/lactate ratio. There was also an early impairment of intestinal permeability in these patients. Conclusions: High arterial and venous cytokine concentrations were detected in patients with acute brain injury. The positive gradient for interleukin 6 suggests a brain origin for this cytokine. Intestinal permeability is also altered in these patients

Efecto agudo de dobutamina y amrinona sobre la hemodinamia y perfusión esplácnica de pacientes en shock séptico / Acute effect of dobutamine and amrinone on hemodynamics and splanchnic perfusion in septic shock patients

Background: Vasoactive drugs used in the reanimation of septic patients, can modify splanchnic perfusion. Aim: To compare the effects of dobutamine and amrinone on gastric intramucosal pH (pHi), lactate levels and hemodynamics in surgical patients with compensated septic shock. Patients and methods: Fourteen postoperative patients with abdominal sepsis and compensated septic shock (pHi <7.32 or lactate >2.5 mmol/l) were studied in a prospective, randomized, unblinded study. Patients were randomized to receive (Group 1, n=7) dobutamine at 5 µg/Kg/min or (Group 2, n=7) amrinone at 5 µg/Kg/min. Hemodynamic data, arterial lactate and pHi were measured before and 30, 60 and 120 minutes after starting drug infusion. Results: Both drugs were associated with a decrease in lactate levels. Dobutamine infusion, but not amrinone, increased gastric pHi, as well as cardiac index and oxygen delivery. Conclusions: An improvement in gastric pHi associated with an increase in oxygen delivery, was observed with dobutamine. Amrinone showed no effect at the fixed, low dose used in the study

Apoyo ventilatorio en pacientes con patología aguda del sistema nervioso central / Ventilatory support in patients with head injuries

Patients with severe head injury are prone to pulmonary complications that result in hypoxemia or hypercarbia, which could worsen their neurological condition. A rational ventilatory approach requires a good knowledge of respiratory and neurological pathophysiology. Airway management is of prime importance in neurological patients. Prophylactic chronic hyperventilation in head trauma is no longer recommended since it could impair cerebral perfusion, although transient hypocarbia could be of benefit to some patients. The use of low or moderate positive and expiratory pressure levels apparently improves oxygenation without worsening intracranial pressure. Ventilatory management should be closely monitored and adjusted to hemodynamic, respiratory and neurological status to achieve a good outcome

Experiencia en monitorización metabólico-cerebral en pacientes críticos neurológicos / Cerebral metabolic monitoring in critical neurological patients

Background: Cerebral metabolic monitoring in critical neurological patients allows the assessment of neuronal tissue response to injury and to plan the best therapy to correct each critical brain situation. Aim: To evaluate the usefulness of cerebral metabolic monitoring in patients with acute cerebral injury. Patients and methods: A retrospective analysis of 29 patients with acute brain injury, in whom a catheter was located in the bulb of the jugular vein to perform a cerebral metabolic monitoring. These patients were compared with others that were not subjected to this monitoring. The evolution at six months of follow up was assessed using the Glasgow outcome score, considering a favorable evolution when this score was 4 or greater. Results: Patients with an hyperemic state on admission or after optimization of therapy did not have hospital mortality, and 73 per cent had Glasgow outcome score of 4 or greater at six months of follow up. On the other hand, 50 per cent of those with hypoperfusion or global ischemia died during hospitalization and 72 per cent had a Glasgow outcome score of 3 or less at six months. Patients not subjected to cerebral metabolic monitoring behave as those with hypoperfusion or global ischemia. Conclusions: Cerebral metabolic monitoring is an useful tool to optimize the management of patients with acute cerebral injury, and those patients with an hyperemic cerebral state have the best prognosis

Insuficiencia hepática aguda fulminante: presentación de un modelo canino por intoxicación con acetaminofeno / Acute fulminant liver failure: presentation of a dog model by acetaminofen poisoning

La carencia de donantes oportunos en casos de insuficiencia hepática aguda fulminante (IHAF) requiere contar con sistemas de soporte hepático transitorio. Para ensayarlos antes de su uso clínico es necesario tener modelos animales de IHAF estandarizados y reproducibles. Nuestro objetivo fue establecer un modelo canino de IHAF por intoxicación oral con acetaminofeno (ACE), para obtener una necrosis hepática (NH) superior al 60 por ciento y determinar los cambios en diferentes variables bioquímicas susceptibles de ser corregidas en modelos de soporte hepático. Para ello se utilizaron 22 perros a los cuales se les administró ACE por sonda gástrica en 3 grupos (Gr): A: 500 mg/kg (n= 5), B: 750 mg/kg (n= 10) y C: 1000 mg/kg (n= 7). En ellos se determinaron los valores basases de diferentes variables bioquímicas de función hepática. Los animales fueron observados clínicamente, y entre las 22 y 24 h post-intoxicación (po.i.) se realizó una 2º determinación de los mismos parámetros en los perros que sobrevivieron. Finalmente se realizó una biopsia hepática, y en los perros fallecidos una necropsia. Se analizó el grado de NH obtenida, su relación con la mortalidad y los resultados de las variables bioquímicas pre y po.i. con diferentes pruebas estadísticas. Resultados: Sobrevivieron 19 animales al procedimiento basal. De ellos, en 10 (52,6 por ciento) se obtuvo una NH >60 por ciento (0, 56 y 83 por ciento de los Gr A, B y C respectivamente, p< 0,05). El 80 por ciento de estos animales (5/6 del Gr C y 319 del Gr B) falleció entre las 14 y 26 h po.i. posterior a un cuadro clínico y bioquímico de falla hepática aguda. En 3 animales no se observó NH, todos del Gr A. No falleció ningún animal con NH < 60 por ciento (p< 0,01). El análisis de las variables bioquímicas pre y po.i. mostró un trastorno metálico importante en todos los animales intoxicados, dosis dependiente, con una mayor sensibilidad para los cambios en los niveles de bilirrubina y transaminasas. En conclusión, con dosis entre 750 y 1000 mg/kg de ACE oral se establece un modelo canino de 1 HAF válido para ser utilizado en la evaluación de sistemas de soporte hepático transitorio

Hipoxemia nocturna después de cirugía abdominal: factores asociados y rol de la oxigenoterapia / Nocturnal hypoxemia after abdominal surgery: associated factors and usefulness of oxygen therapy

Fifteen elective patients (6 M, 9 F, 51+-8 years old) scheduled for laparotomy (n=8) or laparoscopy (n=7) were studied. Ventilatory parameters and pulse oximetry were measured pre and postoperatively. Patients were randomly assigned to receive oxygen by nasal cannula either during the first or the second postoperative night. PONH (Sat2 85) developed in seven patients (47 per cent)of which four had undergone laparoscopic surgery. PONH was more frequent in mildly obese patients and those presenting preoperative hypoxemia (p=0.03). Peak flow was lower in patients presenting PONH (p=0.04). In five patients, PONH was associated with significant tachycardia. Oxygen administration was associated with a higher SatO2 and prevented PONH in 6/7 patients. PONH is a common event in patients older than 40 years scheduled for open or laparascopic abdominal surgery, and develops more frequently in those with preoperative nocturnal hypoxemia and greater ventilatory impairment. PONH can be prevented, most of the time, with oxygen administration

Variación volumétrica con la modificación del umbral de disparo en pacientes sometidos a desconexión del ventilador mecánico / Volumetric variations with the trigger threshold modification in patients submitted to mechanical ventilator desconection

El entrenamiento de la musculatura inspiratoria durante el weaning ventilatorio es fundamental para aumentar sus capacidades y cualidades motoras a través de una planificación que considere tanto las reservas energéticas aeróbicas como anaeróbicas. Estas últimas son responsables de acciones musculares de alta intensidad y limitadas en el tiempo. La determinación del umbral de disparo máximo, que probablemente corresponda a una de las actividades, y la influencia de esta variable en el volumen corriente son descritas en el presente estudio

Pacientes con síndrome de distress respiratorio agudo del adulto: efectos del óxido nítrico inhalado sobre intercambio gaseoso y la hemodinamia / Patients with acute adult respiratory distress syndrome: effects of inhalated nitric oxide on gas exchange and hemodynamics

Adult respiratory distress syndrome is highly prevalent in intensive care units and has a high mortality. Lately, nitric oxide has been used as adjuvant therapy. To study the effects of nitric oxide inhalation in patients with adult respiratory distress syndrome, 12 patients were subjected to nitric oxide inhalation at a concentration of 10 parts per million, during 30 minutes. At the end of the nitric oxide inhalation period, there was an improvement of PaO2/FIOa ratio from 89ñ32 to 111ñ43 mm Hg and 16 percent reduction of lung shunting (Qs/Qt). Nitric oxide inhalation at a concentration of 10 parts per million improved arterial oxygenation and reduced pulmonary shunting in patients with adult respiratory distress syndrome

Inhibición de la vía del óxido nítrico en el shock séptico refractario / Inhibition of nitric oxide way in the refractary septic shock

To assess the acute effects of methylene blue infusion, an inhibitor of nitric oxyde synthesis, on hemodynamic parameters in patients with refractory septic shock. Fourteen patients admitted to intensive care units with septic shock of diverse etiologies and unable to maintain median arterial pressures over 60 mm Hg with the use of at least 2 vasoactive drugs, were studied. All received a 1 mg/kg bolus of methylene blue. Hemodinamic parameters were measured before and 30, 60, 120 and 180 min after the bolus. Systolic and diastolic blood pressure and systemic vascular resistance increased in all patients. There were no significant changes in cardiac output, oxygen consumption or extraction. Methylene blue has an acute pressor effect in patients with septic shock

Apoyo respiratorio estracorpóreo: experiencia en el tratamiento de la insuficiencia respiratoria aguda severa / Extracorporeal respiratory assistance: experience in the treatment of severe acute respiratory failure

Acute respiratory distress syndrome (ARDS) secondary to systemic injury has a high mortality. Symptomatic treatment with mechanical ventilation, PEEP and high levels of inspired oxygen is effective for most of the patients. When ventilatory support fails in reversing hypoxemia, extracorporeal respiratory assistance has been advocated as a temporary treatment until lung repair occurs. We described our experience in eleven patients (9M, 2F, 41ñ16 yo) with severe ARDS refractory to conventional treatment and expected to die if not assisted with extracorporeal oxugenation. All patients required invasive monitoring; seven needed continuous renal therapy because of concurrent renal failure. Venous-venous percutaneous cannulation and systemic anticoagulation were performed and axtracorporeal oxygenation and CO2 removal started with blood pump flows of 20 to 30 percent of patient cardiac output. Improved oxygenation and decreased CO2 levels were immediately observed in 10/11 patients. One patient failed to have reversal of hypoxemia because recirculation and died shortly after initiation of extracorporeal therapy. Plasma leak syndrome and bleeding were observed in 3 and 2 patients respectively. Extracorporeal assistance was mantained for 52ñ34 h (19-134). Five (45 percent) patients were weaned off the pump and two (18 percent) survived and were discharged. Despite the high cos, extracorporeal respiratory assistance, when applied to selected patients, can reverse hypoxia and may save some previously unsalvagable patients allowing them to return to a normal life