Verônica Amado

Recomendações brasileiras de ventilação mecânica 2013. Parte I

Perspectives on invasive and noninvasive ventilatory support for critically ill patients are evolving, as much evidence indicates that ventilation may have positive effects on patient survival and the quality of the care provided in intensive care units in Brazil. For those reasons, the Brazilian Association of Intensive Care Medicine (Associacao de Medicina Intensiva Brasileira - AMIB) and the Brazilian Thoracic Society (Sociedade Brasileira de Pneumologia e Tisiologia - SBPT), represented by the Mechanical Ventilation Committee and the Commission of Intensive Therapy, respectively, decided to review the literature and draft recommendations for mechanical ventilation with the goal of creating a document for bedside guidance as to the best practices on mechanical ventilation available to their members. The document was based on the available evidence regarding 29 subtopics selected as the most relevant for the subject of interest. The project was developed in several stages, during which the selected topics were distributed among experts recommended by both societies with recent publications on the subject of interest and/or significant teaching and research activity in the field of mechanical ventilation in Brazil. The experts were divided into pairs that were charged with performing a thorough review of the international literature on each topic. All the experts met at the Forum on Mechanical Ventilation, which was held at the headquarters of AMIB in Sao Paulo on August 3 and 4, 2013, to collaboratively draft the final text corresponding to each sub-topic, which was presented to, appraised, discussed and approved in a plenary session that included all 58 participants and aimed to create the final document.

Desmame e interrupção da ventilação mecânica

A retirada da ventilacao mecânica e uma medida impor-tante na terapia intensiva. A utilizacao de diversos termos para definir este processo pode dificultar a avaliacao de sua duracao, dos diferentes modos e protocolos e do prognos-tico. Por esse motivo, e importante a definicao precisa dos termos, como se segue:

Effect of a quality improvement intervention to decrease delays in antibiotic delivery in pediatric febrile neutropenia: A pilot study

PURPOSE Guidelines recommend the early (less than 1 hour) initiation of antibiotics for patients with severe sepsis. We hypothesize that a simple quality improvement intervention, leaving the first dose of broad-spectrum antibiotics available in the emergency cart, decreases the time to delivery of antibiotics and reduces medical complications in pediatric oncologic patients with febrile neutropenia. MATERIALS AND METHODS Before and after observation of time to antibiotic delivery. The study population included patients (age ≤18 years) undergoing chemotherapy who were admitted in a pediatric intensive care unit with fever related to an infection as a major diagnostic category. Twenty-five patient charts were reviewed for each period. Data were retrospectively collected with a standardized form. RESULTS Time to antibiotic delivery was significantly reduced in the post-intervention period, from a median 164 minutes (interquartile range, 108-172 minutes) to a median 55 minutes (interquartile range, 18-225 minutes). The proportion of patients receiving antibiotics in less than 60 minutes increased from 0% (95% confidence interval, 0%-14%) in the preintervention period to 52% (95% confidence interval, 30%-74%; P < .001) in the post-intervention period. Complication rates were low during both periods. CONCLUSION Our results suggest that simple interventions can reduce time to antibiotic administration in a selected group of patients in a pediatric intensive care unit.

Tratamiento médico y quirúrgico de la hipertensión pulmonar tromboembólica crónica: experiencia en un único centro

INTRODUCTION Pulmonary endarterectomy (PE) is the treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to analyze our experience in the medical and surgical management of CTEPH. METHODS We included 80 patients diagnosed with CTEPH between January 2000 and July 2012. Thirty two patients underwent PE and 48 received medical treatment (MT). We analyzed functional class (FC), six-minute walking distance (6MWD) and pulmonary hemodynamics. Mortality in both groups and periods were analyzed. RESULTS Patients who underwent PE were younger, mostly men, and had longer 6MWD. No differences were observed in pulmonary hemodynamics or FC at diagnosis. One year after treatment, all PE patients versus 41% in MT group were at FCI-II. At follow-up, the PE group showed greater increase in 6MWD, and greater reduction in mean pulmonary arterial pressure and pulmonary vascular resistance than the MT group (P<.05). Overall survival in the MT group at 1 and 5years was 83% and 69%, respectively. Conditional survival in patients alive 100days post-PE at 1 and 5years was 95% and 88%, respectively. Surgical mortality in operated patients in the first period (2000-2006) was 31,3%, and 6,3% in the second (2007-2012). CONCLUSIONS PE provides good clinical results, and improves pulmonary hemodynamics in patients who successfully overcome the immediate postoperative period. After a learning period, the current operatory mortality in our center is similar to international standards.

Respiratory mechanics and lung tissue remodeling in a hepatopulmonary syndrome rat model.

Intrapulmonary vasodilation is a hallmark of the hepatopulmonary syndrome (HPS). However, its effects on respiratory mechanical properties and lung morphology are unknown. To determine these effects, 28 rats were randomly divided to control and experimental HPS groups (eHPS). The spontaneous breathing pattern, gas exchange, respiratory system mechanical properties, and lung and liver morphology of the rats were evaluated. Tidal volume, minute ventilation and mean inspiratory flow were significantly reduced in the eHPS group. Chest wall pressure dissipation against the resistive and viscoelastic components and elastic elastance were increased in the eHPS group. The lung resistive pressure dissipation was lower but the viscoelastic pressure was higher in the eHPS group. The airway volume proportion of collagen and elastic fibers was increased in the eHPS animals (16% and 51.7%; P<0.05 and P<0.001, respectively). The proportion of collagen volume in the vasculature increased 29% in the eHPS animals (P<0.01). HPS presents with respiratory system mechanical disarray as well as airway and vascular remodeling.

Inspiratory flow-volume curve in snoring patients with and without obstructive sleep apnea

We analyzed the flow-volume curves of 50 patients with complaints of snoring and daytime sleepiness in treatment at the Pneumology Unit of the University Hospital of Brasília. The total group was divided into snorers without obstructive sleep apnea (OSA) (N = 19) and snorers with OSA (N = 31); the patients with OSA were subdivided into two groups according to the apnea/hypopnea index (AHI): AHI < 20/h (N = 14) and AHI > 20/h (N = 17). The control group (N = 10) consisted of nonsmoking subjects without complaints of snoring, daytime sleepiness or pulmonary diseases. The population studied (control and patients) consisted of males of similar age, height and body mass index (BMI); spirometric data were also similar in the four groups. There was no significative difference in the ratio of forced expiratory and inspiratory flows (FEF50%/FIF50%) in any group: control. 0.89; snorers, 1.11; snorers with OSA (AHI < 20/h), 1.42, and snorers with OSA (AHI > 20/h), 1.64. The FIF at 50% of vital capacity (FIF50%) of snoring patients with or without OSA was lower than the FIF50% of the control group (P < 0.05): snorers 4.30 l/s; snorers with OSA (AHI < 20/h) 3.69 l/s; snorers with OSA (AHI > 20/h) 3.17 l/s and control group 5.48 l/s. The FIF50% of patients with severe OSA (AHI > 20/h) was lower than the FIF50% of snorers without OSA (P < 0.05): 3.17 l/s and 4.30 l/s, respectively. We conclude that 1) the FEF50%/FIF50% ratio is not useful for predicting OSA, and 2) FIF50% is decreased in snoring patients with and without OSA, suggesting that these patients have increased upper airway resistance (UAR).

Pulmonary arterial hypertension and sepsis: prothrombotic profile and inflammation can changes pulmonary mechanics?

Pulmonary arterial hypertension (PAH) is associated to cellular and structural alterations of lung vasculature. Endothelial dysfunction promotes vasoconstriction, smooth muscle hypertrophy, intimal proliferation, angioproliferative plexiform lesions, and in situ thrombosis increasing pulmonary vascular resistance and arterial stiffness. Indeed, an inflammatory component has been defined in PAH on the last years. Sepsis is a systemic complex syndrome, of infectious origin. The presence of inflammation is well established in this condition and it is also considered a risk factor for acute lung injury. Thrombotic events play important role in sepsis pathophysiology. The association between PAH and sepsis potentiate the metabolic oxygen consumption/offer imbalance, with very high mortality risk. Furthermore, it is possible that the association of these two conditions should intensify thrombotic events on pulmonary microcirculation, reducing area of pulmonary vascular bed available for blood flow. For the other side, an inflammation synergism observed on these two conditions should increase the respiratory system impedance.

Accuracy of pulmonary auscultation to detect abnormal respiratory mechanics: A cross-sectional diagnostic study

Pulmonary auscultation is a method used in clinical practice for the evaluation and detection of abnormalities relating to the respiratory system. This method has limitations, as it depends on the experience and hearing acuity of the examiner to determine adventitious sounds. In this context, its important to analyze whether there is a correlation between auscultation of lung sounds and the behavior of the respiratory mechanical properties of the respiratory system in patients with immediate postoperative cardiac surgery.

The influence of lung function and muscular strength on the functional capacity of chronic obstructive pulmonary disease patients.

AIM To determine which variable (forced expiratory volume in 1 second (FEV1), partial pressure of oxygen in arterial blood (PaO2), nocturnal hypoxaemia and muscular strength of femoral quadriceps) can predict the distance walked in the six-minute walk test (6MWT) by COPD patients. METHODS A cross-sectional and observational study of thirty patients referred to a pulmonary rehabilitation programme at a university hospital. Lung function was evaluated by spirometry, arterial blood gas analysis and nocturnal oximetry. Muscle function was evaluated by quadriceps strength and functional capacity by the 6MWT. RESULTS Bivariate regression analysis showed that quadriceps strength, was the only variable to correlate significantly with the distance walked in the 6MWT (p=0.002), accounting for 38% of the 6MWT variance. The statistical relationship established for these variables was 1kg of quadriceps strength equalled 5.9 metres walked in the 6MWT. CONCLUSIONS Our results showed the importance of lower limb muscle strength in submaximal exercise testing. We conclude that femoral quadriceps muscle strength is the only one of the variables studied which can predict the distance COPD patients walk in the 6MWT.

Correlation between mild hypoxaemia and limb skeletal muscle function in chronic obstructive pulmonary disease – Pilot study

RATIONALE Exercise capacity in COPD patients depends on the degree of airflow obstruction, the severity of the hypoxaemia and skeletal muscle function. Muscle atrophy and weakness are considered systemic consequences of COPD and are associated with reduced exercise capacity. AIMS To investigate the correlation between mild hypoxaemia and muscular strength, muscular fatigue and functional capacity in COPD patients. METHODS Ten patients enrolled on a PRP at the Hospital Universitário de Brasília - HUB were included in this study. Lung function was evaluated by spirometry and arterial blood gas analysis. Functional evaluation was made using the 6MWT and using isometric contraction of deltoid and quadriceps muscles. RESULTS There were positive correlations between PaO2, quadriceps strength (r2 = 0.61 and p = 0.007) and PaO2 and the 6MWT (r2 = 0.96, p = 0.001). There were negative correlations between PaO2 and median frequency of quadriceps (r2 = -0.42 and p = 0.04). We observed significant correlation between quadriceps strength and the 6MWT (r2 = 0.67 and p = 0.001). There was negative correlation between median frequency of quadriceps and the 6MWT (r2 = -0.42 and p = 0.04). We did not observe any correlation between PaO2 and strength or median frequency of deltoid muscle. CONCLUSIONS PaO2 has important correlations with muscular function variables. The main negative impact of mild hypoxaemia and precocious limb muscular disability on COPD patients is decreased functional capacity.