Severe Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome is characterized by an increase of the permeability of the lungs’ alveolar-capillary membranes, leading to the extravasation of liquid rich in proteins inside the alveolar spaces that turns air-filled lungs into heavy high-osmotic pressure liquid-filled lungs. The consequence is the collapse of the lowermost lung regions, shunt, refractory hypoxemia, decrease in lungs’ compliance and increase in dead spaces that are more pronounced with the severity of the permeability changes of the pulmonary alveoli-capillary membrane. According to the recent Berlin definition, severe acute respiratory distress syndrome is defined by bilateral pulmonary infiltrates of recent onset (less than 1 week) in a patient with a risk factor for ARDS that has a PaO2/FIO2 equal or less than 100 with a positive end-expiratory pressure equal or more than 5 cm H2O with no evidence of cardiac failure or hypervolemia. Severe ARDS patients present a higher mortality ratio, a more difficult mechanical ventilatory support (higher airway pressures with low tidal ventilation and higher PaCO2 levels) and benefits for adjunctive ventilatory support therapy. The recommended mechanical ventilatory support in severe ARDS is with low tidal ventilation (less than 6 mL/Kg predicted body weight) with driving inspiratory pressures less than 15 cm H2O, respiratory rate sufficient to keep adequate minute ventilation and PaCO2 levels. PEEP higher than 15 cm H2O and prolonged prone position are recommended for more severe patients to improve their survival. Adjunctive recruitment maneuvers can be used to improve oxygenation and allow more homogeneous ventilation and PEEP titration. In refractory hypoxemia and especially in younger patients with prognosis, extra-corporeal veno-venous membrane oxygenation support can be used

Managing patients with dengue fever during an epidemic: the importance of a hydration tent and of a multidisciplinary approach

<p>Abstract</p> <p>Background</p> <p>Dengue fever is one of the most common tropical diseases worldwide. Early detection of the disease, followed by intravenous fluid therapy in patients with dengue hemorrhagic fever (DHF) or with warning signs of dengue has a major impact on the prognosis. The purpose of this study is to describe the care provided in a hydration tent, including early detection, treatment, and serial follow-up of patients with dengue fever.</p> <p>Findings</p> <p>The analysis included all patients treated in the hydration tent from April 8 to May 9, 2008. The tent was set up inside the premises of the 2^ndMilitary Firemen Group, located in Meier, a neighborhood in Rio de Janeiro, Brazil. The case form data were stored in a computerized database for subsequent assessment. Patients were referred to the tent from primary care units and from secondary city and state hospitals. The routine procedure consisted of an initial screening including vital signs (temperature, blood pressure, heart rate, and respiratory rate), tourniquet test and blood sampling for complete blood count. Over a 31-day period, 3,393 case recordings were seen at the hydration tent. The mean was 109 patients per day. A total of 2,102 initial visits and 1,291 return visits were conducted. Of the patients who returned to the hydration tent for reevaluation, 850 returned once, 230 returned twice, 114 returned three times, and 97 returned four times or more. Overall, 93 (5.3%) patients with DHF seen at the tent were transferred to a tertiary hospital. There were no deaths among these patients.</p> <p>Discussion</p> <p>As the epidemics were already widespread and there were no technical conditions for routine serology, all cases of suspected dengue fever were treated as such. Implementing hydration tents decrease the number of dengue fever hospitalizations.</p

Brazilian Sepsis Epidemiological Study (BASES study)

INTRODUCTION: Consistent data about the incidence and outcome of sepsis in Latin American intensive care units (ICUs), including Brazil, are lacking. This study was designed to verify the actual incidence density and outcome of sepsis in Brazilian ICUs. We also assessed the association between the Consensus Conference criteria and outcome METHODS: This is a multicenter observational cohort study performed in five private and public, mixed ICUs from two different regions of Brazil. We prospectively followed 1383 adult patients consecutively admitted to those ICUs from May 2001 to January 2002, until their discharge, 28th day of stay, or death. For all patients we collected the following data at ICU admission: age, gender, hospital and ICU admission diagnosis, APACHE II score, and associated underlying diseases. During the following days, we looked for systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, and septic shock criteria, as well as recording the sequential organ failure assessment score. Infection was diagnosed according to CDC criteria for nosocomial infection, and for community-acquired infection, clinical, radiological and microbiological parameters were used. RESULTS: For the whole cohort, median age was 65.2 years (49–76), median length of stay was 2 days (1–6), and the overall 28-day mortality rate was 21.8%. Considering 1383 patients, the incidence density rates for sepsis, severe sepsis and septic shock were 61.4, 35.6 and 30.0 per 1000 patient-days, respectively. The mortality rate of patients with SIRS, sepsis, severe sepsis and septic shock increased progressively from 24.3% to 34.7%, 47.3% and 52.2%, respectively. For patients with SIRS without infection the mortality rate was 11.3%. The main source of infection was lung/respiratory tract. CONCLUSION: Our preliminary data suggest that sepsis is a major public health problem in Brazilian ICUs, with an incidence density about 57 per 1000 patient-days. Moreover, there was a close association between ACCP/SCCM categories and mortality rate

Effects of recruitment maneuver during expiration and inspiration analyzed by thoracic CT scan in patients with acute lung injury and acute respiratory distress syndrome

O objetivo da Estratégia de Recrutamento Máximo (ERM) guiada pela TC de tórax é minimizar a quantidade de colapso alveolar e os mecanismos de lesão induzida pela ventilação mecânica (VILI). Os objetivos deste trabalho são comparar por meio da análise quantitativa das imagens obtidas pela TC durante ERM, em pacientes com SDRA, os seguintes parâmetros: colapso, hiperdistensão Tidal Recruitment (TR), Tidal Stretch (TS) e a distribuição de ar nos pulmões Métodos - Doze pacientes foram transportados para a sala de TC e seqüências de imagens foram obtidas durante a pausa expiratória e inspiratória ao longo da ERM. A ERM consistiu em ventilação modo Pressão Controlada com diferencial fixo de pressão 15 cmH2O e elevações progressivas da PEEP de 10 - 45 cmH2O (fase de recrutamento) e titulação da PEEP (25 - 10 cmH2O) FR=10 - 15 irpm, relação I:E 1:1 e FiO2 1.0. Os pulmões foram divididos em quatro regiões de acordo com o eixo esterno - vertebral (1 anterior e 4 posterior) Resultados - A idade media da população estudada foi de 46 ± 20,5 anos e cerca de 92% dos pacientes tinham SDRA de origem primária. Com o objetivo de manter o recrutamento alcançado pela ERM foram necessários níveis elevados de PEEP média de 23,7 ± 2,3 cmH2O. A relação PaO2/FiO2 aumentou de 131,6 ± 37,6 para 335,9±58,7 (p<0,01) após a titulação da PEEP. A quantidade de colapso global diminuiu de 54 ± 8% (P10pré) para 4,8 ± 6% (P45) (p<0,01), e em P25pós foi mantido em níveis baixos 6,7 ± 6% (p=1,0). Em relação ao TR global, diminuiu de P10pre (4 ± 4%) para P45 (1 ± 1%) (p=0,029), e também foi mantido em níveis baixos após a titulação da PEEP em P25pós (p=1,0). Quanto à hiperdistensão, houve aumento estatisticamente significativo entre P10pré e P45 (p=0,032), embora em termos absolutos este aumento foi inferior a 5%. A comparação entre P25pré e P25pós revelou que não houve diferença entre eles (p=1,0). Não houve aumento do Tidal Hyperinflation entre P10pré e P45 (p=0,95). O Tidal Stretch também diminuiu durante a ERM e foi mantido em níveis baixos em P25pós, semelhantes aos observados em P45. Em P10pre durante pausa expiratória, quase 80% do ar se localizava distribuído na metade anterior dos pulmões. Durante ERM a distribuição de ar foi progressivamente em direção à metade posterior, até que em P25pós atingiu quase 40% (p<0,01). Discussão - A análise tomográfica detalhada destes 12 pacientes portadores de SDRA apresentou como principais resultados que a Estratégia de Recrutamento Máximo guiada por TC de tórax reduziu de forma significativa a quantidade de colapso pulmonar global, de Tidal Recruitment, de Tidal Stretch sem, no entanto, intensificar significativamente a geração de hiperdistensão. Foram necessários níveis elevados de PEEP (cerca de 25 cmH2O em média) para a manutenção do recrutamento adquirido e para garantir distribuição mais homogênea do ar nos pulmões. A elevação da PEEP de 10 cmH2O pra 20 cmH2O, sem a realização de manobra de recrutamento, pode exacerbar os mecanismos de VILI ao invés de diminuí-los. A ERM não promove aumento relevante da hiperdistensão, frente à imensa contribuição na redução do colapso e dos outros mecanismos de VILI. Conclusões - A ERM e titulação da PEEP guiados pela TC de tórax diminuiu significativamente a quantidade de colapso pulmonar, Tidal Recruitment e Tidal Stretch, sem no entanto, aumentar significativamente a hiperdistensão. A ERM também promoveu distribuição de ar mais homogênea no parênquima pulmonar.The goal of Maximal Recruitment Strategy (MRS) guided by thoracic CT scan is to minimize alveolar collapse and the mechanisms of ventilator induced lung injury (VILI). The objectives of this study were to compare by quantitative analyzes of CT scan image of the lungs obtained during MRS of patients with ARDS, the following parameters: collapse, overdistension, Tidal Recruitment (TR), Tidal Stretch (TS) and the gas distribution throughout the lungs. Methods - Twelve patients were transported to the CT room and sequences of CT scan at expiratory and inspiratory pauses were performed during MRS. MRS consisted of 2 min steps of tidal ventilation with fixed deltaPCV=15 cmH2O and progressive increments in PEEP levels (recruitment 10 - 45 cmH2O) and PEEP titration (25 - 10 cmH2O). RR=10 - 15 bpm, I:E ratio 1:1, and FiO2 1.0. The lungs were divided in 4 regions according to the sternum-vertebral axis (1 anterior and 4 posterior). Results - The mean age of the studied population was 46 ± 20,5 y.o., and 92% of the patients ad primary ARDS. In order to sustain recruitment obtained by MRS, mean PEEP levels of 23,7 ± 2,3 cmH2O were necessary and PaO2/FiO2 ratio increased from 131,6 ± 37,6 to 335,9±58,7 (p<0,01) after MRS and PEEP titration. Global collapse decreased from 54 ± 8% (P10pre) to 4,8 ± 6% (P45) (p<0,01), and was sustained at similar levels at P25post 6,7 ± 6% (p=1,0). Global TR also decreased from P10pre (4 ± 4%) to P45 (1 ± 1%) (p=0,029), and was sustained with the same levels at P25post (p=1,0). Regarding overdistension there was statistically significant increment from P10pre to P45 (p=0,032), although in absolute terms the increment was very low < 5%, and P25pre and P25post were identical (p=1,0). There was no increment of Tidal Hyperinflation from P10pre to P45 (p=0,95). TS also decrease during MRS and was maintained at low levels similar to P45 at titrated PEEP (P25post). At P10pre almost 80% of the air at FRC was located at anterior regions. During MRS the distribution of air was directed towards the posterior regions and at P25post was almost 40% (p<0,01). Discussion - The tomographic analysis revealed that during MRS there was a significantly reduction of pulmonary collapse, Tidal Recruitment and Tidal Stretch, without increasing significantly overdistension. High levels of PEEP were necessary to sustain recruitment obtained during MRS and homogeneous gas distribution throughout the lung parenchyma. When PEEP was increased from P10pre to P20pre there was an increment in TR and TS, without a significantly reduction in absolute mass of collapsed lung, suggesting that it may exacerbate the mechanisms of VILI. MRS does not promote relevant overdistention when balanced by its effects on reduction of the mechanisms of VILI. Conclusions - MRS and PEEP titration guided by CT scan decreased significantly lung collapse, Tidal Recruitment and Tidal Stretch, without increasing significantly overdistension. MRS also promoted a homogeneous gas distribution throughout the lung parenchyma

Low mechanical ventilation times and reintubation rates associated with a specific weaning protocol in an intensive care unit setting: a retrospective study

OBJECTIVES: A number of complications exist with invasive mechanical ventilation and with the use of and withdrawal from prolonged ventilator support. The use of protocols that enable the systematic identification of patients eligible for an interruption in mechanical ventilation can significantly reduce the number of complications. This study describes the application of a weaning protocol and its results. METHODS: Patients who required invasive mechanical ventilation for more than 24 hours were included and assessed daily to identify individuals who were ready to begin the weaning process. RESULTS: We studied 252 patients with a median mechanical ventilation time of 3.7 days (interquartile range of 1 to 23 days), a rapid shallow breathing index value of 48 (median), a maximum inspiratory pressure of 40 cmH(2)0, and a maximum expiratory pressure of 40 cm H(2)0 (median). Of these 252 patients, 32 (12.7%) had to be reintubated, which represented weaning failure. Noninvasive ventilation was used postextubation in 170 (73%) patients, and 15% of these patients were reintubated, which also represented weaning failure. The mortality rate of the 252 patients studied was 8.73% (22), and there was no significant difference in the age, gender, mechanical ventilation time, and maximum inspiratory pressure between the survivors and nonsurvivors. CONCLUSIONS: The use of a specific weaning protocol resulted in a lower mechanical ventilation time and an acceptable reintubation rate. This protocol can be used as a comparative index in hospitals to improve the weaning system, its monitoring and the informative reporting of patient outcomes and may represent a future tool and source of quality markers for patient care