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In about 20% of patients admitted to an Intensive Care Unit (ICU) the indication of mechanical ventilation (MV) is a neurological disease. These patients have a prolonged MV stay and high mortality. The appropriate use of MV in patients with acute brain injury (ABI) is critical considering that MV by itself is able to induce or worsen an underlying lung injury. Patients with ABI have a higher risk to develop pulmonary complications. During endotracheal intubation the activation of airway reflexes should be prevented, because they may increase intracranial pressure. Tracheostomy is indicated to improve airway management and it is performed in about 33% of these patients. Indications for MV are loss of spontaneous respiratory effort, changes in lung compliance, gas exchange impairment and ventilatory failure due to muscle fatigue or neuromuscular junction dysfunction. During MV, hypoxemia should be avoided. The pC0(2) level has a critical role in cerebral blood flow regulation; therefore a normal pCO must be maintained in order to guarantee an optimal cerebral blood flow. Despite that, hypocapnia has been used in patients with increased intracranial pressure, at the present it is not recommended. Its use should be limited to the emergency management of intracranial hypertension, while the underlying cause is being treated. Non-conventional ventilatory modes as prone position ventilation, high-frequency oscillatory ventilation and extracorporeal C02 removal can be used in patients with ABI. All of them have specific risks and should be employed cautiously This paper reviews upper airway management and MV in patients with acute brain injury.

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In about20 percent of patients admitted to an Intensive Care Unit (ICU) the indica-tion of mechanical ventilation (MV) is a neurological disease. These patients have a prolonged MV stay and high mortality. The appropriate use of MV in patients with acute brain injury (ABI) is critica! considering that MV by itself is oble to induce or worsen an underlying lung injury. Patients with ABI have a higher risk to develop pulmonary complications. During endotracheal intubation the activation of airway reflexes should beprevented, because they may increase intracranialpressure. Tracheostomy is indicated to improve airway management and it is performed in about 33 percent of these patients. Indications for MV are loss of spontaneous respira-tory effort, changes in lung compliance, gas exchange impairment and ventilatory failure due to muscle fatigue or neuromuscular junction dysfunction. During MV, hypoxemia should be avoided. The pC0(2) level has a critica! role in cerebral blood flow regulation; therefore a normal pCO must be maintained in order to guarantee an optimal cerebral blood flow. Despite that, hypocapnia has been used in patients with increased intracranial pressure, at the present it is not recommended. Its use should be limited to the emergency management of intracranial hypertension, while the underlying cause is beingtreated. Non-conventional ventilatory modes asprone position ventilation, high-frequency oscillatory ventilation and extracorporeal C02 removal can be used in patients with ABI. All ofthem have specific risks and should be employed cautiously This paper reviews upper airway management and MV in patients with acute brain injury.

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Background: Mechanical ventilation may contribute to lung injury and then enhance systemic inflammation. Optimal ventilatory parameters such as tidal volume (V T) and positive end expiratory pressure (PEEP) can be determined using different methods. Low flow pressure volume (P/V-LF) curve is a useful tool to assess the respiratory system mechanics and set ventilatory parameters. Aim: To set V T and PEEP according P/V-LF curve analysis and evaluate its effects on gas exchange and hemodynamic parameters. Materials and methods: Twenty seven patients underwent P/V-LF within the first 72 hours of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). P/V-LF curves were obtained from the ventilator and both lower and upper inflexion points determined. Gas exchange and hemodynamic parameters were measured before and after modifying ventilator settings guided by P/V-LF curves. Results: Ventilatory parameters set according P/V-LF curve, led to a rise of PEEP and reduction of V T: 11.6±2.8 to 14.1±2.1 cm H2O, and 9.7±2.4 to 8.8±2.2 mL/kg (p <0.01). Arterial to inspired oxygen fraction ratio increased from 158.0±66 to 188.5±68.5 (p <0.01), and oxygenation index was reduced, 13.7±8.2 to 12.3±7.2 (p <0.05). Cardiac output and oxygen delivery index (IDO2) were not modified. Demographic data, gas exchange improvement and respiratory system mechanics showed no significant difference between patients with extra-pulmonary and pulmonary ALI/ARDS. There was no evidence of significant adverse events related with this technique. Conclusion: P/V-LF curves information allowed us to adjust ventilatory parameters and optimize gas exchange without detrimental effects on oxygen delivery in mechanically ventilated ALI/ARDS patients.

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En la última década se ha observado un incremento de la literatura disponible sobre hipertensión intrabdominal (HIA) y síndrome compartimental del abdomen. Dado las importantes implicancias fisiopatológicas del aumento de la presión intrabdominal (PIA) en la función de órganos dentro y fuera del abdomen, este tópico es y será trascendente en los próximos años para una población de pacientes críticamente enfermos tanto neonatales, pediátricos como adultos. El objetivo de la presente revisión es efectuar una puesta al día sobre definiciones, epidemiología, metodología de medición, implicancias fisiopatológicas, hallazgos radiológicos y opciones terapéuticas. Mensajes claves a conocer por el lector son: (1) el índice de masa corporal y la resucitación con volumen predicen el desarrollo de HIA; (2) la HIA aumenta las presiones intratorácicas, intracraneana y de llenado cardíaco, y disminuye la compliance ventricular izquierda, de la pared torácica y total del sistema respiratorio; (3) la HIA causa atelectasia y aumenta el contenido de agua extravascular pulmonar; (4) la mejor presión positiva de fin de espiración (PEEP) debe ser indicada para contrarrestar la HIA; (5) estrategias de ventilación protectora deben de estar orientadas por DPpl (presión plateau-PIA); (6) presiones transdiafragmáticas e indicadores volumétricos reflejan mejor la precarga; (7) la HIA es un predictor independiente de falla renal aguda; (8) la HIA gatilla translocación bacteriana y desarrollo de síndrome de falla orgánica múltiple; (9) se recomienda la monitorización de la presión de perfusión abdominal en casos seleccionados.

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Background: Stroke is the second cause of mortality and the first cause of morbidity in Chile and worldwide. Nowadays there is a major interest in introducing new therapies applying evidence based medicine for these patients. Aim: To describe the clinical profile of patients attended after a stroke, to determine stroke subtypes and their risk factors. Material and methods: Retrospective review of clinical records of 459 patients (mean age 65±48 years, 238 female) that were admitted to our unit during a period of 37 months. Results: Sixty three percent of patients had an ischemic stroke, 14% had an hemorrhagic stroke, 15% had a transient ischemic attack, 2% had a cerebral venous thrombosis and 6% a subarachnoidal hemorrhage. The global mortality was 1%. Seventy percent of patients had a history of high blood pressure. Conclusions: The most common type of stroke is ischemic and high blood pressure is the main risk factor.

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A subgroup of patients infected with the Hantavirus develops a pulmonary syndrome (HPS) characterized by severe acute respiratory failure and myocardial depression, that has a high mortality rate. Extracorporeal life support (ECLS) could be a valuable therapeutic tool in such patients. We report a 24 years old male with HPS that was successfully managed when an arterio-venous shunt was added to a conventional veno-arterial ECLS technique. Precise criteria have been developed to predict which patients should be considered for this treatment.

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Background:Monitoring of cardiac preload by determination of pulmonary artery occlusion pressure (PAOP) has been traditionally used to guide fluid therapy to optimize cardiac output (CO). Since factors such as intrathoracic pressure and ventricular compliance may modify PAOP, volumetric estimators of preload have been developed. The PiCCO system is able to measure CO and intrathoracic blood volume (ITBV) by transpulmonary thermodilution. Aim: To compare a volumetric (ITBV) versus a pressure (PAOP) determination to accurately estimate cardiac preload in severely ill patients. Patients and Methods: From June 2001 to October 2003, 22 mechanically ventilated patients with hemodynamic instability underwent hemodynamic monitoring with pulmonary artery catheter (PAC) and PiCCO system. ITBV index (ITBVI), PAOP and CI were measured simultaneously by both methods. One hundred thirty eight deltas (D) were obtained from the difference of ITBVI, PAOP, CI-PAC and CI-PiCCO between 6-12 am and 6-12 pm. Linear regression analysis of DITBVI versus Ð CI-PiCCO and Ð PAOP versus DCI-PAC were made. Results: Mean age of patients was 60.8 ± 19.4 years. APACHE II was 23.9 ± 7. Fifteen patients met criteria for acute respiratory distress syndrome (ARDS). Delta ITBVI significantly correlated with DCI-PiCCO (r=0.54; 95% confidence interval = 0.41-0.65; p <0.01). There was no correlation between DPAOP and Ð CI-PAC. Conclusion: ITBVI correlated better with CI than PAOP, and therefore it seems to be a more accurate estimator of preload in unstable, mechanically ventilated patients.

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BACKGROUND: Stroke is the second cause of mortality and the first cause of morbidity in Chile and worldwide. Nowadays there is a major interest in introducing new therapies applying evidence based medicine for these patients. AIM: To describe the clinical profile of patients attended after a stroke, to determine stroke subtypes and their risk factors. MATERIAL AND METHODS: Retrospective review of clinical records of 459 patients (mean age 65+/-48 years, 238 female) that were admitted to our unit during a period of 37 months. RESULTS: Sixty three percent of patients had an ischemic stroke, 14% had an hemorrhagic stroke, 15% had a transient ischemic attack, 2% had a cerebral venous thrombosis and 6% a subarachnoidal hemorrhage. The global mortality was 1%. Seventy percent of patients had a history of high blood pressure. CONCLUSIONS: The most common type of stroke is ischemic and high blood pressure is the main risk factor.

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