Objective: To establish the incidence of acute lung injury and acute respiratory distress syndrome, as well as related risk factors and mortality in an intensive care unit. To compare patients developing lung injury with at-risk patients not presenting acute lung injury or acute respiratory distress syndrome. Methods: The study was conducted in the intensive care unit of the Ribeirão Preto Hospital das Clínicas Emergency Room. All patients admitted between May 2001 and April 2002 were monitored prospectively. Clinical data, Acute Physiologic and Chronic Health Evaluation II score, complications, length of stay in the intensive care unit and lung injury data were recorded. Results: Of the 524 patients admitted, 175 (33.4%) presented risk factors for acute lung injury and acute respiratory distress syndrome, 33 (6.3%) developed acute respiratory distress syndrome, and 12 (2.3%) developed acute lung injury. The main risk factors were pneumonia (37.7%), shock (32.0%), multiple trauma (24.6%) and sepsis (21.1%). Patients developing acute lung injury had higher Acute Physiologic and Chronic Health Evaluation II scores (p < 0.05), more frequently presented sepsis (p = 0.001), developed more complications (p = 0.001) and presented greater mortality (p = 0.001). The main cause of death was multiple organ failure (38.5%). Conclusion: The incidence of acute lung injury and acute respiratory distress syndrome was 2.3% and 6.3%, respectively.

Keywords: Respiratory distress syndrome, adult/epidemiology; Respiratory distress syndrome, adult/mortality;

Introduction: The diagnosis of diffuse lung disease is still a challenge for the pediatric intensive care physician. Routine clinical examinations and laboratory tests are frequently negative. The objective of this study was to evaluate the diagnostic potential, the impact on therapy and the rate of complications of open lung biopsy in children with undiagnosed diffuse lung disease, respiratory failure and inappropriate response to initial therapy. Methods: From January 1987 to January 1997, 29 children with diffuse pulmonary disease of unknown etiology, respiratory failure (PaO2 /FiO2 < 300) and no response to previous treatments were considered for open lung biopsy. Newborns, children with known chronic pulmonary disease and children with untreatable shock or coagulopathy were excluded. All biopsies were performed by a thoracic surgeon by a microthoracotomy in the lung shown to be the most affected by X-ray examination. Tissue samples were analyzed in terms of cultures, light microscopy, electron microscopy and immunofluorescence microscopy, according to the pathologist's decision. Results: All biopsies (100%) resulted in at least one histological diagnosis and in 20 patients (68.9%) it was obtained a specific diagnosis. The most frequent histological patterns found were: non-specific interstitial pneumonitis with variable degrees of fibrosis in 18 cases; bronchiolitis in eight cases and pulmonary hypertension in three cases. Regarding the most frequent specific diagnosis, six children were found with cytomegalovirus infection, three with Pneumocystis carinii, three with adenovirus and three with respiratory syncytial virus infection. These data induced a change in therapy in 20 children (68.9%). The most frequent changes in therapy were the use of corticosteroids in 14 children and a review of the antibiotic regimen in six patients. Seven patients (24.1%) presented with complications that were easily resolved. There were 13 deaths, probably due to the critical conditions of these patients, all unrelated to the procedure. Conclusions: Open lung biopsy, though an invasive procedure, should be considered in the evaluation of selected children with undiagnosed diffuse lung disease, respiratory failure and with no satisfactory response to previous therapies.

Acute respiratory distress syndrome (ARDS) is characterized by diffuse alveolar damage, and evolves progressively with three phases: exsudative, fibroproliferative, and fibrotic. In the exudative phase, there are interstitial and alveolar edemas with hyaline membrane. The fibroproliferative phase is characterized by exudate organization and fibroelastogenesis. There is proliferation of type II pneumocytes to cover the damaged epithelial surface, followed by differentiation into type I pneumocytes. The fibroproliferative phase starts early, and its severity is related to the patient's prognosis. The alterations observed in the phenotype of the pulmonary parenchyma cells steer the tissue remodeling towards either progressive fibrosis or the restoration of normal alveolar architecture. The fibrotic phase is characterized by abnormal and excessive deposition of extracellular matrix proteins, mainly collagen. The dynamic control of collagen deposition and degradation is regulated by metalloproteinases and their tissular regulators. The deposition of proteoglycans in the extracellular matrix of ARDS patients needs better study. The regulation of extracellular matrix remodeling, in normal conditions or in several pulmonary diseases, such as ARDS, results from a complex mechanism that integrate the transcription of elements that destroy the matrix protein and produce activation/inhibition of several cellular types of lung tissue. This review article will analyze the ECM organization in ARDS, the different pulmonary parenchyma remodeling mechanisms, and the role of cytokines in the regulation of the different matrix components during the remodeling process.

Keywords: Respiratory distress syndrome. Pulmonary alveoli/lesions. Extracellular matrix. Cytokines/ultrastructure.

Objective: To evaluate the impact that the implementation of therapeutic guidelines has on the empirical treatment of nosocomial pneumonia. Methods: A clinical trial, using historical controls and involving current ICU patients who had acquired nosocomial pneumonia, was carried out from June of 2002 to June of 2003. All were treated according to therapeutic guidelines developed by the Commission for Nosocomial Infection Control of the institution (group with intervention). As controls, the medical charts of the patients who acquired nosocomial pneumonia between June of 2000 and June of 2001 (group without intervention) were analyzed. Mortality and mean treatment period, as well as the length of hospital and ICU stays, were determined for the patients who acquired nosocomial pneumonia. Results: Mortality associated with pneumonia was lower in the group treated according to the therapeutic guidelines (26 vs. 53.6%; p = 0.00). As for overall mortality, there was no statistically significant difference between the two periods (51 vs. 57.9%; p = 0.37). There was also no difference in the type of microorganisms isolated, treatment period, length of hospital stay or length of ICU stay. Conclusion: The implementation of therapeutic guidelines for the treatment of nosocomial pneumonia acquired in the ICU can be efficacious in decreasing mortality rates.

Keywords: Pneumonia/treatment; Cross infection; Intensive care units; Mortality.

A male farmer, 20 years old, from the countryside of the State of Piauí, developed acute respiratory infection. Despite adequate antimicrobial therapy, there was worsening respiratory manifestations demanding mechanical ventilation. Radiographs showed diffuse pulmonary infiltrates. PaO2/FiO2 was 58. Direct microscopy and culture from tracheal aspirates disclosed Coccidioides immitis. Autochthonous cases of coccidioidomycosis have only recently been described in Brazil, most of them from the State of Piauí. C. immitis has been isolated from humans, dogs and armadillos (Dasypus novemcinctus), and also from soil samples of armadillo's burrows. Therapeutic failure to antimicrobials and patient's origin from recognized endemic areas should alert for the possibility of acute pulmonary coccidioidomycosis.

Objective: To compare the American-European Consensus Conference (AECC) definition of acute respiratory distress syndrome (ARDS) to autopsy findings. Methods: All patients who died in the intensive care unit of the Federal University of Juiz de Fora University Hospital between 1995 and 2003 and were submitted to autopsy were included in the study. Patient clinical charts were reviewed to establish whether cases met the AECC criteria for a diagnosis of ARDS, histologically defined as the presence of diffuse alveolar damage (DAD). Results: During the study period, 592 patients died, and 22 were submitted to autopsy. Of those 22 patients, 10 (45%) met the AECC criteria, and 7 (32%) met the histopathological criteria for DAD. The AECC clinical criteria presented a sensitivity of 71% (95%CI: 36-92%) and a specificity of 67% (95%CI: 42-85%). The positive and negative predictive values were, respectively, 50 and 83%, whereas the positive and negative likelihood ratios were, respectively, 2.33 and 0.47. The histopathological findings in the 5 patients who met AECC criteria but did not present DAD were pneumonia (n = 2), pulmonary embolism (n = 1), tuberculosis (n = 1), and cryptococcosis (n = 1). Conclusion: The accuracy of the AECC definition of ARDS was godless than satisfactory. Due to the low positive predictive value and the low positive likelihood ratio, other hypotheses must be considered when ARDS is suspected.

Keywords: Respiratory distress syndrome, adult; Diagnostic Techniques and Procedures; Autopsy.

Objective: To assess whether the use of ELMO, a helmet for noninvasive ventilation created in Brazil, had a positive impact on the prognosis of patients with hypoxemic respiratory failure caused by severe COVID-19. Methods: This is a retrospective study of 50 critically ill COVID-19 patients. Epidemiological, clinical, and laboratory data were collected on ICU admission, as well as before, during, and after ELMO use. Patients were divided into two groups (success and failure) according to the outcome. Results: ELMO use improved oxygenation parameters such as Pao2, Fio2, and the Pao2/Fio2 ratio, and this contributed to a gradual reduction in Fio2, without an increase in CO2, as determined by arterial blood gas analysis. Patients in the success group had significantly longer survival (p < 0.001), as determined by the Kaplan-Meier analysis, less need for intubation (p < 0.001), fewer days of hospitalization, and a lower incidence of acute kidney injury in comparison with those in the failure group. Conclusions: The significant improvement in oxygenation parameters, the longer survival, as reflected by the reduced need for intubation and by the mortality rate, and the absence of acute kidney injury suggest that the ELMO CPAP system is a promising tool for treating ARDS and similar clinical conditions.

Keywords: Respiratory distress syndrome; COVID-19; Noninvasive ventilation; Intensive care units.

Poor sleep quality is a consistently reported by patients in the ICU. In such a potentially hostile environment, sleep is extremely fragmented and sleep architecture is unconventional, with a predominance of superficial sleep stages and a limited amount of time spent in the restorative stages. Among the causes of sleep disruption in the ICU are factors intrinsic to the patients and the acute nature of their condition, as well as factors related to the ICU environment and the treatments administered, such as mechanical ventilation and drug therapy. Although the consequences of poor sleep quality for the recovery of ICU patients remain unknown, it seems to influence the immune, metabolic, cardiovascular, respiratory, and neurological systems. There is evidence that multifaceted interventions focused on minimizing nocturnal sleep disruptions improve sleep quality in ICU patients. In this article, we review the literature regarding normal sleep and sleep in the ICU. We also analyze sleep assessment methods; the causes of poor sleep quality and its potential implications for the recovery process of critically ill patients; and strategies for sleep promotion.

Keywords: Sleep; Sleep deprivation; Intensive care units.

Background: Tracheostomy is a procedure commonly required in the intensive care unit. In the last two decades, the use of the percutaneous method has increased in parallel with improvements in the technique. Objective: To describe our experience in employing the percutaneous method over the last 3.5 years. Methods: We created, retrospectively, a database of prospective tracheostomy data related to 78 patients evaluated between January 2000 and July 2003. We used the percutaneous tracheostomy techniques of either progressive dilatation (in 36 patients) or forceps dilatation (in 42 patients). Data are expressed as number of occurrences or median with interquartile ranges. Results: The mean age of the patients was 66 (range, 43-75), and the median APACHE II score was 16 (range, 12-21). The median time spent on mechanical ventilation prior to tracheostomy was 14 days (range, 10-17 days). Of the 78 patients studied, 18 (23%) died while in the intensive care unit. The most common cause of admission was acute central nervous system disturbance (in 45%). Most of the tracheostomies performed were indicated due to difficulty in weaning from mechanical ventilation (in 50%) or to Glasgow Coma scores consistently lower than 8 (in 49%). Bronchoscopy was used in all but 6 of the procedures. There were complications in 33% of the procedures. The most common complication was light bleeding, without need for transfusion. No patient died due to complications arising from the procedure. Conclusion: Percutaneous tracheostomy is reasonable and safe when performed in an intensive care unit.

Keywords: Tracheostomy/methods. Respiration, Artificial/methods. Respiratory insufficiency/therapy. Respiratory insufficiency/complications.

Background: There is a wide variability in clinical practice for treating acute asthma (AA) in the emergency room (ER) interfering in the quality of management. Objective: To evaluate the impact of a clinical protocol for care of acute asthma in the ER of the Hospital de Clínicas de Porto Alegre. Method: In this hospital a cross-sectional study was conducted before and after implementation of the protocol, of consecutive patients presenting with acute asthma in the adult ER (age ³ 12 years). The intention was to measure the effect of recommendations on the objective assessment of severity, utilization of diagnostic tools, proposed therapy, not recommended therapy and on the outcomes. Results: The pre-protocol group comprised 108 patients and the protocol group comprised 96 patients. There was a significant increase in the use of pulse oximetry (8% to 77%, p<0.001) and PEFR (5% to 21%, p<0.001). There was an increase in the utilization of radiology (33% to 66%, p<0.001) and in that of blood tests (11% to 25%, p=0.016). There was also an increase in the number of patients receiving the three recommended nebulizations in the first hour (22% to 36%, p=0.04). Although the overall use of corticosteroids did not change, there was a significant increase in the use of oral steroids (8% to 28%, p<0.001). There was no significant difference in the not recommended therapy, time of stay and outcomes. Conclusion: The acute asthma clinical protocol used in the ER was associated to a positive effect on the objective assessment of severity of asthma and on the use of the recommended therapy. No other significant influence on the treatment or on the outcome was perceived.

Keywords: Clinical protocols. Asthma. Emergency medicine.

Objective: To evaluate the incidence of viral infection in patients with acute asthma treated in the emergency room. Methods: We conducted a cohort study of patients aged 12 and older presenting to the emergency room of the Hospital de Clínicas de Porto Alegre with acute asthma. Nasopharyngeal aspirate was collected, and antigens were detected through indirect immunofluorescence staining for respiratory syncytial virus, adenovirus and influenza, as well as for parainfluenza types 1, 2, 3 and 4. Data were collected regarding demographic characteristics, medical history, the attack that led to the current emergency room visit, and clinical outcomes. Results: From March to July of 2004, 49 patients were examined for viral infection of the respiratory tract. Respiratory viruses were identified in 6 patients (3 with adenovirus, 2 with influenza A, 1 with parainfluenza type 1). The mean age of the patients with viral infection of the respiratory tract was 61.7 ± 11.5 years, compared with 41.7 ± 20.9 years for the patients without such infection (p = 0.027). There were no other significant differences in clinical characteristics or outcomes. Conclusion: The incidence of viral infection of the respiratory tract in acute asthma patients 12 years and older treated in an emergency room was 12.2%, which confirms that viral infection is a significant precipitant of acute asthma for patients in this age bracket.

Keywords: Emergency Service, Hospital; Vírus diseases/prevention & control; Asthma; Respiratory tract infections; Influenza A virus, human

Objective: To identify factors predictive of mortality in patients admitted to the ICU with tuberculosis (TB)/HIV coinfection in the Manaus, Amazon Region. Methods: This was a retrospective cohort study of TB/HIV coinfected patients over 18 years of age who were admitted to an ICU in the city of Manaus, Brazil, between January of 2011 and December of 2014. Sociodemographic, clinical, and laboratory variables were assessed. To identify factors predictive of mortality, we employed a Cox proportional hazards model. Results: During the study period, 120 patients with TB/HIV coinfection were admitted to the ICU. The mean age was 37.0 ± 11.7 years. Of the 120 patients evaluated, 94 (78.3%) died and 62 (66.0%) of those deaths having occurred within the first week after admission. Data on invasive mechanical ventilation (IMV) and ARDS were available for 86 and 67 patients, respectively Of those 86, 75 (87.2%) underwent IMV, and, of those 67, 48 (71.6%) presented with ARDS. The factors found to be independently associated with mortality were IMV (p = 0.002), hypoalbuminemia (p = 0.013), and CD4 count < 200 cells/mm3 (p = 0.002). Conclusions: A high early mortality rate was observed among TB/HIV coinfected ICU patients. The factors predictive of mortality in this population were IMV, hypoalbuminemia, and severe immunosuppression.

Keywords: Mycobacterium tuberculosis; Critical care; Respiration, artificial; Acquired immunodeficiency syndrome.

Objective: To evaluate the stability of hemodynamic, respiratory and gas exchange variables in an animal model of oleic acid-induced acute lung injury. Methods: This was an experimental study involving 10 mongrel dogs. The variables were measured at baseline, as well as at 30, 60, 90 and 120 min after the administration of oleic acid. In order to analyze repeated measurements, linear and quadratic effects were tested. Mixed linear models with diversified variance and covariance structures were used, depending on the variable studied. Results: We found that mean arterial blood pressure stabilized at 30 min, as did heart rate, pulmonary arterial pressure and pulmonary capillary pressure at 60 min. Respiratory rate, tidal volume, minute volume and respiratory work stabilized at 30 min. Regarding gas exchange variables, PaO2, PaO2/FiO2 ratio and pulmonary shunt fraction stabilized at 30 min. The remaining variables maintained a continuous rise or fall. Conclusions: This oleic acid-induced acute lung injury model is stable for some of the variables tested, although stabilization occurs at different times. The respiratory and gas exchange variables stabilized at 30 min, whereas the hemodynamic variables stabilized at 60 min.

Keywords: Respiratory distress syndrome, adult; Models, animal; Statistical analysis.

Transfusion-related acute lung injury (TRALI) is a serious clinical syndrome associated with the transfusion of plasma-containing blood components. Recently, TRALI has come to be recognized as the leading cause of transfusion-related death in the United States and United Kingdom. This complication typically presents as shortness of breath, hypoxemia, hypotension, fever and noncardiogeneic pulmonary edema, all occurring during or within 6 h after transfusion. Although the mechanism of TRALI has not been fully elucidated, it has been associated with human leukocyte antigen antibodies (class I, class II or neutrophil alloantigens) and with biologically active mediators in stored cellular blood components. Most of the donors implicated in cases of TRALI are multiparous women. Rarely diagnosed, TRALI can be confused with other causes of acute respiratory failure. Greater knowledge regarding TRALI on the part of clinicians could be crucial in preventing and treating this severe complication of blood transfusion.

Keywords: Blood transfusion; Respiratory insufficiency; HLA antigens.

Objetivo: Investigar os efeitos agudos da administração endovenosa de extrato da fumaça do cigarro (EFC) em parâmetros funcionais respiratórios, inflamatórios e histológicos em ratos e comparar esse potencial modelo de lesão pulmonar aguda (LPA) com aquele com o uso de ácido oleico (AO). Métodos: Foram estudados 72 ratos Wistar machos divididos em quatro grupos: tratados somente com soro fisiológico (SF; grupo controle); tratados com EFC e SF (grupo EFC); tratados com SF e AO (grupo AO); e tratados com EFC e AO (grupo EFC/AO). Resultados: As médias de complacência foram significantemente menores nos grupos AO e EFC/AO (2,12 ± 1,13 mL/cmH2O e 1,82 ± 0,77 mL/cmH2O, respectivamente) do que no controle (3,67 ± 1,38 mL/cmH2O). A proporção de neutrófilos e a atividade das metaloproteinases 2 e 9 em lavado broncoalveolar foram significantemente maiores nos grupos AO e EFC/AO que no controle. O acometimento pulmonar avaliado por morfometria foi significantemente maior nos grupos AO e EFC/AO (72,9 ± 13,8% e 77,6 ± 18,0%, respectivamente) do que nos grupos controle e EFC (8,7 ± 4,1% e 32,7 ± 13,1%, respectivamente), e esse acometimento foi significantemente maior no grupo EFC que no grupo controle. Conclusões: A administração endovenosa de EFC, nas doses e tempos deste estudo, associou-se à LPA mínima. O EFC não potencializou a LPA induzida por AO. Estudos adicionais são necessários para esclarecer o papel potencial desse modelo como método de estudo dos mecanismos de agressão pulmonar pelo tabaco.

Keywords: Tabagismo; Lesão pulmonar aguda; Modelos animais.

Objective: To determine the incidence of the reversed halo sign (RHS) in patients with pulmonary infarction (PI) due to acute pulmonary embolism (PE), detected by computed tomography angiography (CTA) of the pulmonary arteries, and to describe the main morphological features of the RHS. Methods: We evaluated 993 CTA scans, stratified by the risk of PE, performed between January of 2010 and December of 2014. Although PE was detected in 164 scans (16.5%), three of those scans were excluded because of respiratory motion artifacts. Of the remaining 161 scans, 75 (46.6%) showed lesions consistent with PI, totaling 86 lesions. Among those lesions, the RHS was seen in 33 (38.4%, in 29 patients). Results: Among the 29 patients with scans showing lesions characteristic of PI with the RHS, 25 (86.2%) had a single lesion and 4 (13.8%) had two, totaling 33 lesions. In all cases, the RHS was in a subpleural location. To standardize the analysis, all images were interpreted in the axial plane. Among those 33 lesions, the RHS was in the right lower lobe in 17 (51.5%), in the left lower lobe in 10 (30.3%), in the lingula in 5 (15.2%), and in the right upper lobe in 1 (3.0%). Among those same 33 lesions, areas of low attenuation were seen in 29 (87.9%). The RHS was oval in 24 (72.7%) of the cases and round in 9 (27.3%). Pleural effusion was seen in 21 (72.4%) of the 29 patients with PI and the RHS. Conclusions: A diagnosis of PE should be considered when there are findings such as those described here, even in patients with nonspecific clinical symptoms.

Keywords: Pulmonary embolism; Pulmonary infarction; Computed tomography angiography.

Background: It is questionable whether pressure-controlled ventilation (PCV) has advantages over volume-cycled ventilation (VCV). Objectives: To compare PCV to VCV with decelerating flow profile during assisted and controlled modes in an acute lung injury experimental model. Methods: Severe acute lung injury (PaO2/FIO2 < 100 mmHg) was induced by oleic acid IV infusion (0.05 mg/kg) in seven dogs. The animals were submitted to PCV and VCV in a randomized sequence. After 40 minutes in the assisted mode, ventilation was changed to the controlled mode after neuromuscular blockade. The tidal volume and the inspiratory time were kept constant throughout the experiment. Results: There were no differences in gas exchange (PaO2 and PaCO2), cardiac output or oxygen delivery (DO2) between VCV and PCV. The same was observed regarding maximum airway and plateau pressures, and also to the static compliance. Oxygen consumption (VO2) after neuromuscular blockade was 124 ± 48 in VCV versus 143 ± 50 ml/min in PCV, p = 0.42. In the assisted mode, there was a statistical trend of a higher VO2 in PCV (219 ± 72 versus 154 ± 67 ml/min in VCV, p = 0.06), that was associated with a statistical trend of a higher oxygen cost of breathing (OCB) during assisted PCV, although without statistical significance (31 ± 77 in VCV versus 75 ± 96 ml/min in PCV, p = 0.23), and also in a lower PvO2 (34 ± 7 in PCV versus 42 ± 6 ml/min in VCV, p = 0.02). These occurred despite a higher maximum inspiratory flow in the assisted mode in PCV (58 ± 9 versus 48 ± 4 L/min in VCV, p = 0.01). In both VCV and PCV the institution of controlled ventilation reduced cardiac debit and DO2 in as much as 20% relative to the assisted mode. Conclusions: The implementation of controlled ventilation improved the oxygen delivery/consumption relationship in this severe and with high OCB acute lung injury model. The PCV offered no additional benefits to VCV and it was associated with a higher OCB during the assisted mode.

Keywords: Artificial respiration. Pulmonary gas exchange. Tidal volume.

Objective: To translate the Richards-Campbell Sleep Questionnaire (RCSQ) and Sleep in the Intensive Care Unit Questionnaire (SICUQ) to Portuguese, making the appropriate cross-cultural adaptations for their use in Brazil, as well as to determine the interobserver reliability of the instruments. Methods: In this study, we evaluated medical and surgical patients admitted to the adult ICU of the Federal University of Paraná Hospital de Clínicas, in the city of Curitiba, Brazil, between June of 2017 and January of 2018. The translation and cross-cultural adaptation of the questionnaires involved the following steps: translation, synthesis, back-translation, revision by an expert panel, approval of the back-translation by the original authors, pretesting, and creation of the final versions. Two researchers applied the Portuguese-language versions in the evaluation of critically ill patients. Interobserver reliability was assessed by calculating the intraclass correlation coefficient (ICC) and 95% CI. Results: The sample comprised 50 patients, of whom 27 (54%) were women. The mean age was 47.7 ± 17.5 years. The main reason for ICU admission, in 10 patients (20%), was cancer. The interobserver reliability of the questionnaires ranged from good to excellent. For the RCSQ, the ICC was 0.84 (95% CI: 0.71-0.90). For SICUQ domains 1-5 (sleep quality and daytime sleepiness), the ICC was 0.75 (95% CI: 0.55-0.86), whereas it was 0.86 (95% CI: 0.76-0.92) for SICUQ domains 6 and 7 (causes of sleep disruption). Conclusions: The cross-culturally adapted, Portuguese-language versions of the RCSQ and SICUQ appear to have good interobserver reliability.

Keywords: Sleep; Intensive care units; Sleep deprivation; Surveys and questionnaires; Translations; Cross-cultural comparison.