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Helium was discovered in 1868 by the French astronomer Pierre-Jules-César Janssen and was first used as a therapeutic treatment for airway obstruction by Barach almost 70 years later, in 1934. Heliox is characterized by its low density, which makes it more fluid under conditions of turbulence, thus minimizing airway pressure and facilitating the occurrence of laminar flow. The present article describes two clinical cases of patients with status asthmaticus subjected to mechanical ventilation and refractory to treatment in whom heliox was used, which allowed optimization of the efficacy of conventional pharmacological treatments. Although heliox is still used sporadically and its true efficacy has not been well demonstrated, the unique physical properties of helium and the theoretical improvement of the airflow in obstructed airways have produced scientific interest and stimulated research. Heliox can be used simultaneously with conventional therapies in cases of serious and refractory exacerbations of severe obstructive disease. [ABSTRACT FROM AUTHOR]

Objective: To analyze the characteristics of children with acute viral bronchiolitis subjected to mechanical ventilation for three consecutive years and to correlate their progression with mechanical ventilation parameters and fluid balance. Methods: Longitudinal study of a series of infants (

Objective: This study assessed pain and observed physiological parameters in sedated and mechanically ventilated children during a routine procedure. Methods: This observational study was performed in a pediatric intensive care unit. Thirty-five children between 1 month and 12 years of age were assessed before, during, and five minutes after an arterial blood collection for gas analysis (painful procedure). Face, Legs, Activity, Cry and Consolability scale was used to assess pain. In addition, patients' heart rate, respiratory rate, peripheral saturation of oxygen and blood pressure (diastolic and systolic) were recorded. COMFORT-B scale was applied before the pain and physiological parameter assessments to verify sedation level of the subjects. Results: There was an increase in Face, Legs, Activity, Cry and Consolability score (p = 0.0001) during painful stimuli. There was an increase in heart rate (p = 0.03), respiratory rate (p = 0.001) and diastolic blood pressure (p = 0.006) due to pain caused by the routine procedure. Conclusions: This study suggests that assessments of pain using standard scales, such as Face, Legs, Activity, Cry and Consolability score, and other physiological parameters should be consistently executed to optimize pain management in pediatric intensive care units. [ABSTRACT FROM AUTHOR]

Objective: To determine the efficacy of lung hyperinflation maneuvers via a mechanical ventilator compared to isolated tracheal aspiration for removing secretions, normalizing hemodynamics and improving lung mechanics in patients on mechanical ventilation. Methods: This was a randomized crossover clinical trial including patients admitted to the intensive care unit and on mechanical ventilation for more than 48 hours. Patients were randomized to receive either isolated tracheal aspiration (Control Group) or lung hyperinflation by mechanical ventilator (MVH Group). Hemodynamic and mechanical respiratory parameters were measured along with the amount of aspirated secretions. Results: A total of 50 patients were included. The mean age of the patients was 44.7 ± 21.6 years, and 31 were male. Compared to the Control Group, the MVH Group showed greater aspirated secretion amount (3.9g versus 6.4g, p = 0.0001), variation in mean dynamic compliance (-1.3 ± 2.3 versus -2.9 ± 2.3; p = 0.008), and expired tidal volume (-0.7 ± 0.0 versus -54.1 ± 38.8, p = 0.0001) as well as a significant decrease in peak inspiratory pressure (0.2 ± 0.1 versus 2.5 ± 0.1; p = 0.001). Conclusion: In the studied sample, the MVH technique led to a greater amount of aspirated secretions, significant increases in dynamic compliance and expired tidal volume and a significant reduction in peak inspiratory pressure. [ABSTRACT FROM AUTHOR]

Objective: Hypercapnia resulting from protective ventilation in acute respiratory distress syndrome triggers metabolic pH compensation, which is not entirely characterized. We aimed to describe this metabolic compensation. Methods: The data were retrieved from a prospective collected database. Variables from patients' admission and from hypercapnia installation until the third day after installation were gathered. Forty-one patients with acute respiratory distress syndrome were analyzed, including twenty-six with persistent hypercapnia (PaCO2 > 50mmHg > 24 hours) and 15 non-hypercapnic (control group). An acid-base quantitative physicochemical approach was used for the analysis. Results: The mean ages in the hypercapnic and control groups were 48 ± 18 years and 44 ± 14 years, respectively. After the induction of hypercapnia, pH markedly decreased and gradually improved in the ensuing 72 hours, consistent with increases in the standard base excess. The metabolic acid-base adaptation occurred because of decreases in the serum lactate and strong ion gap and increases in the inorganic apparent strong ion difference. Furthermore, the elevation in the inorganic apparent strong ion difference occurred due to slight increases in serum sodium, magnesium, potassium and calcium. Serum chloride did not decrease for up to 72 hours after the initiation of hypercapnia. Conclusion: In this explanatory study, the results indicate that metabolic acid-base adaptation, which is triggered by acute persistent hypercapnia in patients with acute respiratory distress syndrome, is complex. Furthermore, further rapid increases in the standard base excess of hypercapnic patients involve decreases in serum lactate and unmeasured anions and increases in the inorganic apparent strong ion difference by means of slight increases in serum sodium, magnesium, calcium, and potassium. Serum chloride is not reduced. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to explore the factors associated with blood oxygen partial pressure and carbon dioxide partial pressure. Methods: The factors associated with oxygen - and carbon dioxide regulation were investigated in an apneic pig model under veno-venous extracorporeal membrane oxygenation support. A predefined sequence of blood and sweep flows was tested. Results: Oxygenation was mainly associated with extracorporeal membrane oxygenation blood flow (beta coefficient = 0.036mmHg/mL/min), cardiac output (beta coefficient = -11.970mmHg/L/min) and pulmonary shunting (beta coefficient = -0.232mmHg/%). Furthermore, the initial oxygen partial pressure and carbon dioxide partial pressure measurements were also associated with oxygenation, with beta coefficients of 0.160 and 0.442mmHg/mmHg, respectively. Carbon dioxide partial pressure was associated with cardiac output (beta coefficient = 3.578mmHg/L/min), sweep gas flow (beta coefficient = -2.635mmHg/L/min), temperature (beta coefficient = 4.514mmHg/ºC), initial pH (beta coefficient = -66.065mmHg/0.01 unit) and hemoglobin (beta coefficient = 6.635mmHg/g/dL). Conclusion: In conclusion, elevations in blood and sweep gas flows in an apneic veno-venous extracorporeal membrane oxygenation model resulted in an increase in oxygen partial pressure and a reduction in carbon dioxide partial pressure 2, respectively. Furthermore, without the possibility of causal inference, oxygen partial pressure was negatively associated with pulmonary shunting and cardiac output, and carbon dioxide partial pressure was positively associated with cardiac output, core temperature and initial hemoglobin. [ABSTRACT FROM AUTHOR]

Evidence-based practices search for the best available scientific evidence to support problem solving and decision making. Because of the complexity and amount of information related to health care, the results of methodologically sound scientific papers must be integrated by performing literature reviews. Although endotracheal suctioning is the most frequently performed invasive procedure in intubated newborns in neonatal intensive care units, few Brazilian studies of good methodological quality have examined this practice, and a national consensus or standardization of this technique is lacking. Therefore, the purpose of this study was to review secondary studies on the subject to establish recommendations for endotracheal suctioning in intubated newborns and promote the adoption of best-practice concepts when conducting this procedure. An integrative literature review was performed, and the recommendations of this study are to only perform endotracheal suctioning in newborns when there are signs of tracheal secretions and to avoid routinely performing the procedure. In addition, endotracheal suctioning should be conducted by at least two people, the suctioning time should be less than 15 seconds, the negative suction pressure should be below 100 mmHg, and hyperoxygenation should not be used on a routine basis. If indicated, oxygenation is recommended with an inspired oxygen fraction value that is 10 to 20% greater than the value of the previous fraction, and it should be performed 30 to 60 seconds before, during and 1 minute after the procedure. Saline instillation should not be performed routinely, and the standards for invasive procedures must be respected. [ABSTRACT FROM AUTHOR]

Objective: To describe post-extubation noninvasive positive pressure ventilation use in intensive care unit clinical practice and to identify factors associated with noninvasive positive pressure ventilation failure. Methods: This prospective cohort study included patients aged ≥ 18 years consecutively admitted to the intensive care unit who required noninvasive positive pressure ventilation within 48 hours of extubation. The primary outcome was noninvasive positive pressure ventilation failure. Results: We included 174 patients in the study. The overall noninvasive positive pressure ventilation use rate was 15%. Among the patients who used noninvasive positive pressure ventilation, 44% used it after extubation. The failure rate of noninvasive positive pressure ventilation was 34%. The overall mean ± SD age was 56 ± 18 years, and 55% of participants were male. Demographics; baseline pH, PaCO2 and HCO3; and type of equipment used were similar between groups. All of the noninvasive positive pressure ventilation final parameters were higher in the noninvasive positive pressure ventilation failure group [inspiratory positive airway pressure: 15.0 versus 13.7cmH2O (p = 0.015), expiratory positive airway pressure: 10.0 versus 8.9cmH2O (p = 0.027), and FiO2: 41 versus 33% (p = 0.014)]. The mean intensive care unit length of stay was longer (24 versus 13 days), p < 0.001, and the intensive care unit mortality rate was higher (55 versus 10%), p < 0.001 in the noninvasive positive pressure ventilation failure group. After fitting, the logistic regression model allowed us to state that patients with inspiratory positive airway pressure ≥ 13.5cmH2O on the last day of noninvasive positive pressure ventilation support are three times more likely to experience noninvasive positive pressure ventilation failure compared with individuals with inspiratory positive airway pressure < 13.5 (OR = 3.02, 95%CI = 1.01 - 10.52, p value = 0.040). Conclusions: The noninvasive positive pressure ventilation failure group had a longer intensive care unit length of stay and a higher mortality rate. Logistic regression analysis identified that patients with inspiratory positive airway pressure ≥ 13.5cmH2O on the last day of noninvasive positive pressure ventilation support are three times more likely to experience noninvasive positive pressure ventilation failure. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether the respiratory variation of the inferior vena cava diameter (ΔDIVC) and right internal jugular vein diameter (ΔDRIJ) are correlated in mechanically ventilated patients. Methods: This study was a prospective clinical analysis in an intensive care unit at a university hospital. Thirty-nine mechanically ventilated patients with hemodynamic instability were included. ΔDIVC and ΔDRIJ were assessed by echography. Vein distensibility was calculated as the ratio of (A) Dmax - Dmin/Dmin and (B) Dmax - Dmin/mean of Dmax - Dmin and expressed as a percentage. Results: ΔDIVC and ΔDRIJ were correlated by both methods: (A) r = 0.34, p = 0.04 and (B) r = 0.51, p = 0.001. Using 18% for ΔDIVC, indicating fluid responsiveness by method (A), 16 patients were responders and 35 measurements showed agreement (weighted Kappa = 0.80). The area under the ROC curve was 0.951 (95%CI 0.830 - 0.993; cut-off = 18.92). Using 12% for ΔDIVC, indicating fluid responsiveness by method (B), 14 patients were responders and 32 measurements showed agreement (weighted Kappa = 0.65). The area under the ROC curve was 0.903 (95%CI 0.765 - 0.973; cut-off value = 11.86). Conclusion: The respiratory variation of the inferior vena cava and the right internal jugular veins are correlated and showed significant agreement. Evaluation of right internal jugular vein distensibility appears to be a surrogate marker for inferior vena cava vein distensibility for evaluating fluid responsiveness. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the clinical characteristics of patients with hematological disease admitted to the intensive care unit and the use of noninvasive mechanical ventilation in a subgroup with respiratory dysfunction. Methods: A retrospective observational study from September 2011 to January 2014. Results: Overall, 157 patients were included. The mean age was 45.13 (± 17.2) years and 46.5% of the patients were female. Sixty-seven (48.4%) patients had sepsis, and 90 (57.3%) patients required vasoactive vasopressors. The main cause for admission to the intensive care unit was acute respiratory failure (94.3%). Among the 157 studied patients, 47 (29.9%) were intubated within the first 24 hours, and 38 (24.2%) underwent noninvasive mechanical ventilation. Among the 38 patients who initially received noninvasive mechanical ventilation, 26 (68.4%) were subsequently intubated, and 12 (31.6%) responded to this mode of ventilation. Patients who failed to respond to noninvasive mechanical ventilation had higher intensive care unit mortality (66.7% versus 16.7%; p = 0.004) and a longer stay in the intensive care unit (9.6 days versus 4.6 days, p = 0.02) compared with the successful cases. Baseline severity scores (SOFA and SAPS 3) and the total leukocyte count were not significantly different between these two subgroups. In a multivariate logistic regression model including the 157 patients, intubation at any time during the stay in the intensive care unit and SAPS 3 were independently associated with intensive care unit mortality, while using noninvasive mechanical ventilation was not. Conclusion: In this retrospective study with severely ill hematologic patients, those who underwent noninvasive mechanical ventilation at admission and failed to respond to it presented elevated intensive care unit mortality. However, only intubation during the intensive care unit stay was independently associated with a poor outcome. Further studies are needed to define predictors of noninvasive mechanical ventilation failure. [ABSTRACT FROM AUTHOR]

Objective: To analyze the correlations of the blood flow/ pump rotation ratio and the transmembrane pressure, CO2 and O2 transfer during the extracorporeal respiratory support. Methods: Five animals were instrumented and submitted to extracorporeal membrane oxygenation in a five-step protocol, including abdominal sepsis and lung injury. Results: This study showed that blood flow/pump rotations ratio variations are dependent on extracorporeal membrane oxygenation blood flow in a positive logarithmic fashion. Blood flow/pump rotation ratio variations are negatively associated with transmembrane pressure (R2 = 0.5 for blood flow = 1500mL/ minute and R2 = 0.4 for blood flow = 3500mL/minute, both with p < 0.001) and positively associated with CO2 transfer variations (R2 = 0.2 for sweep gas flow = 6L/minute, p < 0.001, and R2 = 0.1 for sweep gas flow > 6L/minute, p = 0.006), and the blood flow/pump rotation ratio is not associated with O2 transfer variations (R2 = 0.01 for blood flow = 1500mL/minute, p = 0.19, and R2 = - 0.01 for blood flow = 3500 mL/minute, p = 0.46). Conclusion: Blood flow/pump rotation ratio variation is negatively associated with transmembrane pressure and positively associated with CO2 transfer in this animal model. According to the clinical situation, a decrease in the blood flow/ pump rotation ratio can indicate artificial lung dysfunction without the occurrence of hypoxemia. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the changes in ventilatory mechanics and hemodynamics that occur in patients dependent on mechanical ventilation who are subjected to a standard respiratory therapy protocol. Methods: This experimental and prospective study was performed in two intensive care units, in which patients dependent on mechanical ventilation for more than 48 hours were consecutively enrolled and subjected to an established respiratory physiotherapy protocol. Ventilatory variables (dynamic lung compliance, respiratory system resistance, tidal volume, peak inspiratory pressure, respiratory rate, and oxygen saturation) and hemodynamic variables (heart rate) were measured one hour before (T-1), immediately after (T0) and one hour after (T+1) applying the respiratory physiotherapy protocol. Results: During the period of data collection, 104 patients were included in the study. Regarding the ventilatory variables, an increase in dynamic lung compliance (T-1 = 52.3 ? 16.1mL/ cmH2O versus T0 = 65.1 ? 19.1mL/cmH2O; p < 0.001), tidal volume (T-1 = 550 ? 134mL versus T0 = 698 ? 155mL; p < 0.001), and peripheral oxygen saturation (T-1 = 96.5 ? 2.29% versus T0 = 98.2 ? 1.62%; p < 0.001) were observed, in addition to a reduction of respiratory system resistance (T-1 = 14.2 ? 4.63cmH2O/L/s versus T0 = 11.0 ? 3.43cmH2O/L/s; p < 0.001), after applying the respiratory physiotherapy protocol. All changes were present in the assessment performed one hour (T+1) after the application of the respiratory physiotherapy protocol. Regarding the hemodynamic variables, an immediate increase in the heart rate after application of the protocol was observed, but that increase was not maintained (T-1 = 88.9 ? 18.7 bpm versus T0 = 93.7 ? 19.2bpm versus T+1 = 88.5 ? 17.1bpm; p < 0.001). Conclusion: Respiratory therapy leads to immediate changes in the lung mechanics and hemodynamics of mechanical ventilation-dependent patients, and ventilatory changes are likely to remain for at least one hour. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the efficacy and safety of percutaneous tracheostomy by means of single-step dilation with fiber optic bronchoscopy assistance in critical care patients under mechanical ventilation. Methods: Between the years 2004 and 2014, 512 patients with indication of tracheostomy according to clinical criteria, were prospectively and consecutively included in our study. One-third of them were high-risk patients. Demographic variables, APACHE II score, and days on mechanical ventilation prior to percutaneous tracheostomy were recorded. The efficacy of the procedure was evaluated according to an execution success rate and based on the necessity of switching to an open surgical technique. Safety was evaluated according to post-operative and operative complication rates. Results: The mean age of the group was 64 ? 18 years (203 women and 309 males). The mean APACHE II score was 21 ? 3. Patients remained an average of 11 ? 3 days on mechanical ventilation before percutaneous tracheostomy was performed. All procedures were successfully completed without the need to switch to an open surgical technique. Eighteen patients (3.5%) presented procedure complications. Five patients experienced transient desaturation, 4 presented low blood pressure related to sedation, and 9 presented minor bleeding, but none required a transfusion. No serious complications or deaths associated with the procedure were recorded. Eleven patients (2.1%) presented post-operative complications. Seven presented minor and transitory bleeding of the percutaneous tracheostomy stoma, 2 suffered displacement of the tracheostomy cannula, and 2 developed a superficial infection of the stoma. Conclusion: Percutaneous tracheostomy using the single-step dilation technique with fiber optic bronchoscopy assistance seems to be effective and safe in critically ill patients under mechanical ventilation when performed by experienced intensive care specialists using a standardized procedure. [ABSTRACT FROM AUTHOR]

Objective: To analyze the cost-utility of using extracorporeal oxygenation for patients with severe acute respiratory distress syndrome in Brazil. Methods: A decision tree was constructed using databases from previously published studies. Costs were taken from the average price paid by the Brazilian Unified Health System (Sistema Único de Saúde; SUS) over three months in 2011. Using the data of 10,000,000 simulated patients with predetermined outcomes and costs, an analysis was performed of the ratio between cost increase and years of life gained, adjusted for quality (cost-utility), with survival rates of 40 and 60% for patients using extracorporeal membrane oxygenation. Results: The decision tree resulted in 16 outcomes with different life support techniques. With survival rates of 40 and 60%, respectively, the increased costs were R$=-301.00/-14.00, with a cost of R$=-30,913.00/-1,752.00 paid per six-month quality-adjusted life-year gained and R$=-2,386.00/-90.00 per quality-adjusted life-year gained until the end of life, when all patients with severe ARDS were analyzed. Analyzing only patients with severe hypoxemia (i.e., a ratio of partial oxygen pressure in the blood to the fraction of inspired oxygen <100mmHg), the increased cost was R$=-5,714.00/272.00, with a cost per six-month quality-adjusted life-year gained of R$=-9,521.00/293.00 and a cost of R$=-280.00/7.00 per quality-adjusted life-year gained. Conclusion: The cost-utility ratio associated with the use of extracorporeal membrane oxygenation in Brazil is potentially acceptable according to this hypothetical study. [ABSTRACT FROM AUTHOR]

We report the successful treatment of two patients with aneurismal subarachnoid hemorrhage complicated by severe respiratory failure and refractory septic shock using simultaneous prone position ventilation and high-volume hemofiltration. These rescue therapies allowed the patients to overcome the critical situation without associated complications and with no detrimental effects on the intracranial and cerebral perfusion pressures. Prone position ventilation is now an accepted therapy for severe acute respiratory distress syndrome, and high-volume hemofiltration is a non-conventional hemodynamic support that has several potential mechanisms for improving septic shock. In this manuscript, we briefly review these therapies and the related evidence. When other conventional treatments are insufficient for providing safe limits of oxygenation and perfusion as part of basic neuroprotective care in subarachnoid hemorrhage patients, these rescue therapies should be considered on a case-by-case basis by an experienced critical care team. [ABSTRACT FROM AUTHOR]

Objective: Early weaning from mechanical ventilation is one of the primary goals in managing critically ill patients. There are various techniques and measurement parameters for such weaning. The objective of this study was to describe the practices of ventilatory weaning in adult intensive care units in the city of Cali. Methods: A survey of 32 questions (some multiple choice) evaluating weaning practices was distributed to physiotherapists and respiratory therapists working in intensive care units, to be answered anonymously. Results: The most common strategy for the parameter set was the combination of continuous positive airway pressure with pressure support (78%), with a large variability in pressure levels, the most common range being 6 to 8cmH2O. The most common weaning parameters were as follows: tidal volume (92.6%), respiratory rate (93.3%) and oxygen saturation (90.4%). The most common waiting time for registration of the parameters was >15 minutes (40%). The measurements were preferably obtained from the ventilator display. Conclusion: The methods and measurement parameters of ventilatory weaning vary greatly. The most commonly used method was continuous positive airway pressure with more pressure support and the most commonly used weaning parameters were the measured tidal volume and respiratory rate. [ABSTRACT FROM AUTHOR]

Objective: To identify risk factors for extubation failure and reintubation in newborn infants subjected to mechanical ventilation and to establish whether ventilation parameters and blood gas analysis behave as predictors of those outcomes. Methods: Prospective study conducted at a neonatal intensive care unit from May to November 2011. A total of 176 infants of both genders subjected to mechanical ventilation were assessed after extubation. Extubation failure was defined as the need to resume mechanical ventilation within less than 72 hours. Reintubation was defined as the need to reintubate the infants any time after the first 72 hours. Results: Based on the univariate analysis, the variables gestational age <28 weeks, birth weight <1,000g and low Apgar scores were associated with extubation failure and reintubation. Based on the multivariate analysis, the variables length of mechanical ventilation (days), potential of hydrogen (pH) and partial pressure of oxygen (pO2) remained associated with extubation failure, and the five-minute Apgar score and age at extubation were associated with reintubation. Conclusion: Low five-minute Apgar scores, age at extubation, length of mechanical ventilation, acid-base disorders and hyperoxia exhibited associations with the investigated outcomes of extubation failure and reintubation. [ABSTRACT FROM AUTHOR]

The development of abdominal surgery represents an alternative therapy for the morbidly obese; however, patients undergoing this surgical procedure often experience postoperative pulmonary complications. The use of alveolar recruitment maneuvers and/or perioperative ventilatory strategies is a possible alternative to reduce these complications, focusing on the reduction of postoperative pulmonary complications. In this review, the benefits of perioperative ventilatory strategies and the implementation of alveolar recruitment maneuvers in obese patients undergoing abdominal surgery are described. [ABSTRACT FROM AUTHOR]

In preterm infants, the need for intubation and mechanical ventilation is associated with ventilator-induced lung injuries and subsequent bronchopulmonary dysplasia. The aim of the present review was to improve the understanding of the mechanisms of injury that involve cytokine-mediated inflammation to contribute to the development of new preventive strategies. Relevant articles were retrieved from the PubMed database using the search terms "ventilator-induced lung injury preterm", "continuous positive airway pressure", "preterm", and "bronchopulmonary dysplasia". The resulting data and other relevant information were divided into several topics to ensure a thorough, critical view of ventilation-induced lung injury and its consequences in preterm infants. The role of pro-inflammatory cytokines (particularly interleukins 6 and 8 and tumor necrosis factor alpha) as mediators of lung injury was assessed. Evidence from studies conducted with animals and human newborns is described. This evidence shows that brief periods of mechanical ventilation is sufficient to induce the release of pro-inflammatory cytokines. Other forms of mechanical and non-invasive ventilation were also analyzed as protective alternatives to conventional mechanical ventilation. It was concluded that non-invasive ventilation, intubation followed by early surfactant administration and quick extubation for nasal continuous positive airway pressure, and strategies that regulate tidal volume and avoid volutrauma (such as volume guarantee ventilation) protect against ventilator-induced lung injury in preterm infants. [ABSTRACT FROM AUTHOR]