At the beginning of the COVID-19 pandemic in Chile, in March 2020, a projection indicated that a significant group of patients with pneumonia would require admission to an Intensive Care Unit and connection to a mechanical ventilator. Therefore, a paucity of these devices and other supplies was predicted. The initiative “Un respiro para Chile” brought together many people and institutions, public and private. In the course of three months, it allowed the design and building of several ventilatory assistance devices, which could be used in critically ill patients.

Background: The appropriate use of analgesia, sedation, neuromuscular blockade and the diagnosis and prevention of delirium (ASBD) are associated with better outcomes in critically ill patients at Intensive Care Unit (ICUs). Aim: To know the practices about analgesia, sedation, delirium, and neuromuscular blockade use among healthcare professionals working in adult ICUs in Chile. Material and Methods: An electronic survey was sent to 812 professionals working in ICUs using a previously published instrument, which was adapted and authorized by the author. Results: We received 278 surveys. Fifty two percent of respondents were physicians, 34% nurses and 11% physical therapists. Their age ranged between 30 and 39 years in 43% and was over 50 years in 9%. Eighty four percent evaluated pain routinely, but only 26% use a validated scale. Sedation was routinely evaluated with a validated scale and 73% referred to have a protocol. Neuromuscular block is seldom used, and little monitoring occurs (43%). Delirium is routinely evaluated by 48% of respondents, usually using the CAM-ICU scale. Conclusions: There is a heterogeneous adherence to the ASBD recommended practices. The main gaps are in the assessment of pain, monitoring of neuromuscular blockade and diagnosis of delirium through validated instruments.

RESUMO A distensão excessiva e o recrutamento alveolar pelo volume corrente foram defendidos como os principais mecanismos físicos responsáveis pela lesão pulmonar induzida pelo ventilador. A limitação do volume corrente demonstrou benefícios quanto à sobrevivência em pacientes com síndrome da angústia respiratória aguda e é reconhecida como a pedra fundamental da ventilação protetora. Em contraste, o uso de elevados níveis de pressão positiva expiratória final em estudos clínicos gerou resultados conflitantes e ainda é um assunto controvertido. Nesta revisão, discutimos os benefícios e as limitações da abordagem de pulmão aberto, e debatemos alguns recentes estudos experimentais e clínicos, referentes ao uso de níveis baixos e moderados de pressão positiva expiratória final. Também distinguimos o estiramento dinâmico (volume corrente) do estático (pressão expiratória final positiva e pressão média nas vias aéreas) e discutimos seus papéis na indução da lesão pulmonar induzida pela ventilação. As estratégias com elevada pressão positiva expiratória final claramente diminuem a hipoxemia refratária em pacientes com síndrome da angústia respiratória aguda, porém também aumentam o estiramento estático, que, por sua vez, pode ser lesiva aos pacientes, especialmente para aqueles com nível mais baixo de recrutabilidade pulmonar. Em pacientes com insuficiência respiratória grave, recomenda-se a titulação da pressão positiva expiratória final contra a gravidade da hipoxemia, ou sua aplicação de uma forma decrescente após manobra de recrutamento. Caso sejam observadas elevadas pressões de platô, driving pressure ou pressão média nas vias aéreas, a posição prona ou ventilação ultraprotetora podem ser indicadas para melhora da oxigenação, sem estresse adicional e estiramento dos pulmões.

ABSTRACT Overdistention and intratidal alveolar recruitment have been advocated as the main physical mechanisms responsible for ventilator-induced lung injury. Limiting tidal volume has a demonstrated survival benefit in patients with acute respiratory distress syndrome and is recognized as the cornerstone of protective ventilation. In contrast, the use of high positive end-expiratory pressure levels in clinical trials has yielded conflicting results and remains controversial. In the present review, we will discuss the benefits and limitations of the open lung approach and will discuss some recent experimental and clinical trials on the use of high versus low/moderate positive end-expiratory pressure levels. We will also distinguish dynamic (tidal volume) from static strain (positive end-expiratory pressure and mean airway pressure) and will discuss their roles in inducing ventilator-induced lung injury. High positive end-expiratory pressure strategies clearly decrease refractory hypoxemia in patients with acute respiratory distress syndrome, but they also increase static strain, which in turn may harm patients, especially those with lower levels of lung recruitability. In patients with severe respiratory failure, titrating positive end-expiratory pressure against the severity of hypoxemia, or providing it in a decremental fashion after a recruitment maneuver, is recommended. If high plateau, driving or mean airway pressures are observed, prone positioning or ultraprotective ventilation may be indicated to improve oxygenation without additional stress and strain in the lung.

RESUMO A síndrome cardiopulmonar por hantavírus tem elevada taxa de mortalidade. Sugere-se que uma conexão precoce com oxigenação por membrana extracorpórea melhore os resultados. Relatamos o caso de uma paciente que apresentou síndrome cardiopulmonar por hantavírus e choque refratário, que preenchia os critérios para oxigenação por membrana extracorpórea e que teve resposta satisfatória com uso de hemofiltração contínua de alto volume. A implantação de hemofiltração contínua de alto volume, juntamente da ventilação protetora, reverteu o choque dentro de poucas horas e pode ter levado à recuperação. Em pacientes com síndrome cardiopulmonar por hantavírus, um curso rápido de hemofiltração contínua de alto volume pode ajudar a diferenciar pacientes que podem ser tratados com cuidados convencionais da unidade de terapia intensiva dos que necessitarão de terapias mais complexas, como oxigenação por membrana extracorpórea.

ABSTRACT Hantavirus cardiopulmonary syndrome has a high mortality rate, and early connection to extracorporeal membrane oxygenation has been suggested to improve outcomes. We report the case of a patient with demonstrated Hantavirus cardiopulmonary syndrome and refractory shock who fulfilled the criteria for extracorporeal membrane oxygenation and responded successfully to high volume continuous hemofiltration. The implementation of high volume continuous hemofiltration along with protective ventilation reversed the shock within a few hours and may have prompted recovery. In patients with Hantavirus cardiopulmonary syndrome, a short course of high volume continuous hemofiltration may help differentiate patients who can be treated with conventional intensive care unit management from those who will require more complex therapies, such as extracorporeal membrane oxygenation.

Os tópicos mais importantes na falência hepática fulminante são o edema cerebral e a hipertensão intracraniana. Dentre todas as opções terapêuticas, tem sido relatado que a hipotermia sistêmica induzida em níveis entre 33 - 34ºC reduz a elevação da pressão e aumenta o tempo durante o qual os pacientes podem tolerar um enxerto. Esta revisão discutiu as indicações e os efeitos adversos da hipotermia.

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.

Solid organ transplantation is limited by donor availability. The loss of brain function produces hemodynamic, respiratory, hormonal and metabolic changes that lead to hypotension and organ dysfunction. Management of a potential donor is similar to any critically ill patient. Cardiovascular stability and protective ventilatory support must be pursued, aimed at minimizing the local and systemic inflammatory response that is triggered by brain death. There is no consensus on protocols for hormonal supplementation. The administration of vasopressin analogues and steroids may be beneficial under certain conditions. Appropriate medical management helps to optimize the function of different organs prior to transplantation. This may increase the number of harvested organs and improve their functional outcome in the recipient.

INTRODUÇÃO: A sedação profunda em pacientes gravemente enfermos se associa a uma maior duração da ventilação mecânica e à permanência mais longa na unidade de terapia intensiva. Diversos protocolos foram utilizados para melhorar esses desfechos. Implantamos e avaliamos um protocolo de sedação baseado em analgesia, direcionado por objetivos e cuidado por enfermeiros, em pacientes gravemente enfermos submetidos à ventilação mecânica. MÉTODOS: Realizamos um estudo multicêntrico prospectivo em duas fases (antes e depois), que envolveu 13 unidades de terapia intensiva localizadas no Chile. Após uma fase observacional (grupo observacional, N=155), delineamos, implantamos e avaliamos um protocolo de sedação cuidado por enfermeiros, direcionado por objetivos (grupo de intervenção, N=132) para tratar pacientes que necessitaram de ventilação mecânica por mais do que 48 horas. O parâmetro primário de avaliação foi a obtenção de dias livres de ventilador até o dia 28. RESULTADOS: No grupo de intervenção, a proporção de pacientes com sedação profunda ou coma diminuiu de 55,2 para 44,0%. A incidência de agitação não se alterou entre os períodos, permanecendo em cerca de 7%. Dias livres de ventilador até o dia 28, permanência na unidade de terapia intensiva e mortalidade foram similares em ambos os grupos. Após 1 ano, a presença de sintomas de desordem de estresse pós-traumático nos sobreviventes foi similar entre os grupos. CONCLUSÕES: Delineamos e implantamos no Chile um protocolo de sedação baseado em analgesia, direcionado por objetivos e cuidado por enfermeiros. Embora não se tenha observado melhora nos principais desfechos, observamos que o presente protocolo foi seguro e factível, e que resultou em períodos mais curtos de sedação profunda, sem aumento da agitação.

INTRODUCTION: Deep sedation in critically ill patients is associated with a longer duration of mechanical ventilation and a prolonged length of stay in the intensive care unit. Several protocols have been used to improve these outcomes. We implement and evaluate an analgesia-based, goal-directed, nurse-driven sedation protocol used to treat critically ill patients who receive mechanical ventilation. METHODS: We performed a prospective, two-phase (before-after), non-randomized multicenter study that involved 13 intensive care units in Chile. After an observational phase (observational group, n=155), we designed, implemented and evaluated an analgesia-based, goal-directed, nurse-driven sedation protocol (intervention group, n=132) to treat patients who required mechanical ventilation for more than 48 hours. The primary outcome was to achieve ventilator-free days by day 28. RESULTS: The proportion of patients in deep sedation or in a coma decreased from 55.2% to 44.0% in the interventional group. Agitation did not change between the periods and remained approximately 7%. Ventilator-free days to day 28, length of stay in the intensive care unit and mortality were similar in both groups. At one year, post-traumatic stress disorder symptoms in survivors were similar in both groups. CONCLUSIONS: We designed and implemented an analgesia-based, goal-directed, nurse-driven sedation protocol in Chile. Although there was no improvement in major outcomes, we observed that the present protocol was safe and feasible and that it resulted in decreased periods of deep sedation without increasing agitation.

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.

OBJETIVO: O objetivo deste estudo foi avaliar os efeitos da pressão expiratória final positiva no estiramento, recrutamento e recrutamento e desrecrutamento cíclico avaliados por tomografia computadorizada pulmonar em pacientes com lesão pulmonar aguda/síndrome do desconforto respiratório agudo. MÉTODOS: Trata-se de um estudo aberto, controlado, não randomizado, de intervenção, em pacientes com lesão pulmonar aguda/síndrome do desconforto respiratório agudo. Foram realizados cortes simples de tomografia computadorizada durante pausas inspiratórias e expiratórias com um volume corrente de 6 ml/kg e níveis de pressão expiratória final positiva de 5, 10, 15 e 20 cmH2O. Medimos as densidades do parênquima pulmonar em unidades Hounsfield e calculamos o recrutamento, recrutamento e desrecrutamento cíclico induzidos pela pressão expiratória final positiva, assim como o estiramento. RESULTADOS: O aumento dos níveis de pressão expiratória final positiva aumenta de forma consistente o recrutamento e o estiramento globais (p<0,01), o que se correlacionou de forma significante com a pressão de platô (r²=0,97; p<0,01). O aumento dos níveis de pressão expiratória final positiva aumentou sistematicamente a distensão alveolar em todo o eixo esternovertebral. CONCLUSÃO: A distensão alveolar é um efeito adverso da pressão expiratória final positiva que deve ser ponderado em qualquer paciente em relação ao seus potenciais benefícios no recrutamento. Em razão do número reduzido de pacientes, estes dados devem ser considerados como geradores de hipótese e não limitar a aplicação de valores elevados de pressão expiratória final positiva em pacientes com hipoxemia grave.

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.

Acute liver failure has a mortality rate in excess of 80%. Most deaths are attributed to brain edema with intracranial hypertension and herniation of structures, where ammonium plays a major role in its generation. We report an 18 year-old female with a fulminant hepatic failure caused by virus A infection. The patient developed a profound sopor and required mechanical ventilation. A CT scan showed the presence of brain edema and intracranial hypertension. A Raudemic® catheter was inserted to measure intracranial pressure and brain temperature. Intracranial hypertension became refractory and intravascular hypothermia was started, reducing brain temperature to 33°C. Seventy two hours later, a liver transplantation was performed. After testing graft perfusion, rewarming was started, completing 122 hours of hypothermia at 33°C. The patient was discharged in good conditions after 69 days of hospitalization.

Background: Severe sepsis (SS) is the leading cause of death in the Intensive Care Units (ICU). Aim: To study the prevalence of SS in Chilean ICUs. Material and methods: An observational, cross-sectional study using a predesigned written survey was done in all ICUs of Chile on April 21st, 2004. General hospital and ICU data and the number of hospitalized patients in the hospital and in the ICU at the survey day, were recorded. Patients were followed for 28 days. Results: Ninety four percent of ICUs participated in the survey. The ICU occupation index was 66%. Mean age of patients was 57.7+18 years and 59% were male, APACHE II score was 15+7.5 and SOFA score was 6+4. SS was the admission diagnosis of 94 of the 283 patients (33%) and 38 patients presented SS after admission. On the survey day, 112 patients fulfilled SS criteria (40%). APACHE II and SOFA scores were significantly higher in SS patients than in non SS patients. Global case-fatality ratio at 28 days was 15.9% (45/283). Case-fatality ratio in patients with or without SS at the moment of the survey was 26.7% (30/112) and 8.7% (17/171), respectively p <0.05. Thirteen percent of patients who developed SS after admission, died. Case-fatality ratios for patients with SS from Santiago and the other cities were similar, but APACHE II score was significantly higher in patients from Santiago. In SS patients, the independent predictors of mortality were SS as cause of hospital admission, APACHE II and SOFA scores. Ninety nine percent of SS patients had a known sepsis focus (48% respiratory and 30% abdominal). Eighty five patients that presented SS after admission, had a respiratory focus. Conclusions: SS is highly prevalent in Chilean ICUs and represents the leading diagnosis at admission. SS as cause of hospitalization, APA CHE II and SOFA scores were independent predictors of mortality

Malignant middle cerebral territory infarction represents 5 to 10% of all brain infarctions. Its mortality is 80%, due to brain herniation and it is not reduced by medical treatment. Decompressive hemicraniectomy reduces mortality to 12%, and the subsequent quality of life of patients is acceptable. We report two male patients aged 61 and 54 years, with a malignant middle cerebral territory infarction who were treated with decompressive hemicraniectomy. After two years of follow up, both patients are self-sufficient and live at home with their families

Background: The need of mechanical ventilation among patients with acute neurological diseases is considered a poor prognostic sign. Aim: To determine the mortality and functional recovery of neurological patients requiring mechanical ventilation. Patients and methods: Prospective study of 77 patients (42 men, age 54±19 years, with 11±4 points of Glasgow coma scale (GCS), 61% with cerebrovascular disease), that were admitted to the intensive care unit with neurological disease and that required mechanical ventilation. Functional recovery was assessed at 18 months with Glasgow outcome scale (GOS) and Barthel index. Results: Thirty percent of patients died during follow up. Among surviving patients, 47% had a good recovery or moderate disability, and 74% had a Barthel index equal to or over 70. Arterial hypertension, age over 70 and mechanical ventilation longer than 6 days were associated with bad functional prognosis. Conclusions: Neurological patients requiring mechanical ventilation had a lower mortality than previously reported, and half of the survivors have an independent life. This study supports intensive care management in this group of patients (Rev Méd Chile 2004; 132: 11-8).

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)