Electrical impedance tomography in pulmonary arterial hypertension.

The characterization of pulmonary arterial hypertension (PAH) relies mainly on right heart catheterization (RHC). Electrical impedance tomography (EIT) provides a non-invasive estimation of lung perfusion that could complement the hemodynamic information from RHC. To assess the association between impedance variation of lung perfusion (ΔZQ) and hemodynamic profile, severity, and prognosis, suspected of PAH or worsening PAH patients were submitted simultaneously to RHC and EIT. Measurements of ΔZQ were obtained. Based on the results of the RHC, 35 patients composed the PAH group, and eight patients, the normopressoric (NP) group. PAH patients showed a significantly reduced ΔZQ compared to the NP group. There was a significant correlation between ΔZQ and hemodynamic parameters, particularly with stroke volume (SV) (r = 0.76; P < 0.001). At 60 months, 15 patients died (43%) and 1 received lung transplantation; at baseline they had worse hemodynamics, and reduced ΔZQ when compared to survivors. Patients with low ΔZQ (≤154.6%.Kg) presented significantly worse survival (P = 0.033). ΔZQ is associated with hemodynamic status of PAH patients, with disease severity and survival, demonstrating EIT as a promising tool for monitoring patients with pulmonary vascular disease.

Estimation of Stroke Volume and Stroke Volume Changes by Electrical Impedance Tomography.

BACKGROUND: Electrical impedance tomography (EIT) is a noninvasive imaging method that identifies changes in air and blood volume based on thoracic impedance changes. Recently, there has been growing interest in EIT to measure stroke volume (SV). The objectives of this study are as follows: (1) to evaluate the ability of systolic impedance variations (ΔZsys) to track changes in SV in relation to a baseline condition; (2) to assess the relationship of ΔZsys and SV in experimental subjects; and (3) to identify the influence of body dimensions on the relationship between ΔZsys and SV. METHODS: Twelve Agroceres pigs were instrumented with transpulmonary thermodilution catheter and EIT and were mechanically ventilated in a random order using different settings of tidal volume (VT) and positive end-expiratory pressure (PEEP): VT 10 mL·kg and PEEP 10 cm H2O, VT 10 mL·kg and PEEP 5 cm H2O, VT 6 mL·kg and PEEP 10 cm H2O, and VT 6 mL·kg and PEEP 5 cm H2O. After baseline data collection, subjects were submitted to hemorrhagic shock and successive fluid challenges. RESULTS: A total of 204 paired measurements of SV and ΔZsys were obtained. The 4-quadrant plot showed acceptable trending ability with a concordance rate of 91.2%. Changes in ΔZsys after fluid challenges presented an area under the curve of 0.83 (95% confidence interval, 0.74-0.92) to evaluate SV changes. Conversely, the linear association between ΔZsys and SV was poor, with R from linear mixed model of 0.35. Adding information on body dimensions improved the linear association between ΔZsys and SV up to R from linear mixed model of 0.85. CONCLUSIONS: EIT showed good trending ability and is a promising hemodynamic monitoring tool. Measurements of absolute SV require that body dimensions be taken into account.

The role of target therapies in schistosomiasis-associated pulmonary arterial hypertension.

BACKGROUND: Schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) may be one of the most prevalent forms of pulmonary arterial hypertension (PAH) worldwide. However, the clinical and hemodynamical response to specific PAH therapy in Sch-PAH is not known. METHODS: We retrospectively analyzed the charts of all patients with Sch-PAH who initiated specific PAH treatment between June 2003 and June 2010 in a single PAH reference center in São Paulo, Brazil. Clinical and hemodynamical data were retrospectively collected and evaluated in two periods: baseline and posttreatment. RESULTS: The study population consisted of 12 patients with Sch-PAH. They were treated with phosphodiseterase-5 inhibitors (seven patients), endothelin receptor antagonists (four patients), or combination therapy (one patient). Mean treatment period was 34.9 ± 15.5 months. Patients with Sch-PAH presented significant improvements in terms of functional class, 6-min walk test distance (439 ± 85 to 492 ± 79 m, P = .032), cardiac index (2.66 ± 0.59 to 3.08 ± 0.68 L/min/m(2), P = .028), and indexed pulmonary vascular resistance (20.7 ± 11.6 to 15.9 ± 9 W/m(2), P = .038) with the introduction of specific PAH treatment. CONCLUSIONS: We conclude that specific PAH therapy may be of benefit to patients with Sch-PAH, considering clinical, functional, and hemodynamic parameters.

Schistosomiasis and pulmonary hypertension.

Schistosomiasis is one of the most prevalent chronic infectious diseases in the world. One of its most severe complications, pulmonary hypertension, occurs in up to 5% of patients with hepatosplenic schistosomiasis. The prevalence of schistosomiasis is so overwhelming that schistosomiasis-associated pulmonary hypertension (Sch-PH) may be the most prevalent cause of pulmonary hypertension around the world. Multiple pathways have been described as potential mechanisms of disease in Sch-PH, such as egg embolism, inflammatory disease or pulmonary blood overflow. The possible physiopathological mechanisms will be discussed in this article, as well the disease's clinical course and response to the treatment available.

The role of imaging techniques in the assessment of pulmonary circulation.

Knowledge of the structure and function of pulmonary circulation has evolved considerably in the last few decades. The use of non-invasive imaging techniques to assess the anatomy and function of the pulmonary vessels and heart has taken on added importance with the recent advent of novel therapies. Imaging findings not only constitute a diagnostic tool but have also proven to be essential for prognosis and treatment follow-up. This article reviews the myriad of imaging methods currently available for the assessment of pulmonary circulation, from the simple chest X-ray to techniques that are more complex and promising, such as electrical impedance tomography.

O papel dos exames de imagem na avaliação da circulação pulmonar / The role of imaging techniques in the assessment of pulmonary circulation

O conhecimento sobre a estrutura e a função da circulação pulmonar evoluiu sensivelmente nas últimas décadas. A utilização de exames de imagem não invasivos para a avaliação da anatomia e da função dos vasos pulmonares e do coração ganhou ainda mais importância com o advento de tratamentos até então indisponíveis. Além do auxílio para o diagnóstico, as informações obtidas têm se mostrado fundamentais para o estabelecimento de prognósticos e como parâmetro de sucesso dos tratamentos. A presente revisão discute os diversos métodos que podem ser utilizados para a avaliação da circulação pulmonar por imagens existentes nos dias de hoje, desde técnicas amplamente disponíveis e de relativa baixa complexidade técnica, como a radiografia de tórax, até métodos complexos e promissores, como a tomografia de impedância elétrica.

Knowledge of the structure and function of pulmonary circulation has evolved considerably in the last few decades. The use of non-invasive imaging techniques to assess the anatomy and function of the pulmonary vessels and heart has taken on added importance with the recent advent of novel therapies. Imaging findings not only constitute a diagnostic tool but have also proven to be essential for prognosis and treatment follow-up. This article reviews the myriad of imaging methods currently available for the assessment of pulmonary circulation, from the simple chest X-ray to techniques that are more complex and promising, such as electrical impedance tomography.

The epidemiology of acute respiratory failure in hospitalized patients: a Brazilian prospective cohort study.

PURPOSE: The purpose of this study was to assess risk factors associated with the development of acute respiratory failure (ARF) and death in a general intensive care unit (ICU). MATERIALS AND METHODS: Adults who were hospitalized at 12 surgical and nonsurgical ICUs were prospectively followed up. Multivariable analyses were realized to determine the risk factors for ARF and point out the prognostic factors for mortality in these patients. RESULTS: A total of 1732 patients were evaluated, with an ARF prevalence of 57%. Of the 889 patients who were admitted without ARF, 141 (16%) developed this syndrome in the ICU. The independent risk factors for developing ARF were 64 years of age or older, longer time between hospital and ICU admission, unscheduled surgical or clinical reason for ICU admission, and severity of illness. Of the 984 patients with ARF, 475 (48%) died during the ICU stay. Independent prognostic factors for death were age older than 64 years, time between hospital and ICU admission of more than 4 days, history of hematologic malignancy or AIDS, the development of ARF in ICU, acute lung injury, and severity of illness. CONCLUSIONS: Acute respiratory failure represents a large percentage of all ICU patients, and the high mortality is related to some preventable factors such as the time to ICU admission.

Survival in schistosomiasis-associated pulmonary arterial hypertension.

OBJECTIVES: The objective of this study was to evaluate the natural history of untreated schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) patients as compared to idiopathic pulmonary arterial hypertension (IPAH) with respect to hemodynamics recorded at presentation and 36 months survival. BACKGROUND: Schistosomiasis (Sch) is one of the most prevalent chronic infectious diseases in the world. Nevertheless data regarding one of its most severe clinical complications, pulmonary arterial hypertension (PAH), is scarce. METHODS: We retrospectively analyzed case notes of all consecutive patients diagnosed of Sch-PAH and IPAH referred to the Heart Institute in São Paulo, Brazil, between 2004 and 2008. None of the Sch-PAH received PAH specific treatment whereas all IPAH patients did. RESULTS: Sch-PH patients (n = 54) had less severe pulmonary hypertension as evidenced by lower levels of pulmonary vascular resistance (11.3 +/- 11.3 W vs. 16.7 +/- 10.6 W; p = 0.002) and mean pulmonary artery pressure (56.7 +/- 18.7 mm Hg vs. 64.6 +/- 17.4 mm Hg; p = 0.01) and higher cardiac output (4.62 +/- 1.5 l/min vs. 3.87 +/- 1.5 l/min; p = 0.009) at presentation than IPAH patients (n = 95). None of the Sch-PAH patients demonstrated a positive response to acute vasodilator testing, whereas 16.2% of IPAH patients did (p = 0.015). Survival rates at 1, 2, and 3 years were 95.1%, 95.1%, and 85.9% and 95%, 86%, and 82%, for Sch-PAH and IPAH, respectively (p = 0.49). Both groups had a higher survival rate when compared to IPAH survival as estimated by the NIH equation (71%, 61%, and 52%, respectively). CONCLUSIONS: Sch-PAH has a more benign clinical course than IPAH despite a lack of demonstrable acute vasoreactivity at hemodynamic evaluation.

Surgical myocardial revascularization of patients with ischemic cardiomyopathy and severe left ventricular disfunction.

OBJECTIVE: To determine long-term survival, identify preoperative factors predictive of a favorable outcome, and assess functional improvement after coronary artery bypass grafting in patients with advanced left ventricular dysfunction. METHODS: Between 1995 and 2001, 244 patients who underwent coronary artery bypass grafting and had a preoperative left ventricular ejection fraction less than or equal to 35% were included. left ventricular ejection fraction was determined by uniplanar or biplanar ventriculography during left heart catheterization. Indication for surgery was predominance of tissue viability. Functional improvement was evaluated through echocardiography and gated scintigraphy at exercise/rest. Survival was determined by Kaplan-Meier analysis. RESULTS: Mean left ventricular ejection fraction was 29+/-4% (ranged from 9% to 35%). An average of 3.01 coronary bypass grafts per patient were performed. In-hospital mortality was 3.7% (9 patients). The 4-year survival rate was 89.7%. Multivariate correlates of favorable short- and long-term outcome were preoperative New York Heart Association Funcional classification for congestive heart failure class I/II, lower PAsP, higher left ventricular ejection fraction and gated left ventricular ejection fraction Ex/Rest ratio >5%. Left ventricular ejection fraction rise from 32+/-5% to 39+/-5%, p <0.001. Gated left ventricular ejection fraction at exercise/rest increased markedly after surgery: from 27+/-8%/23+/-7% to 37+/-5%/31+/-6%, p <0.001. CONCLUSIONS: In selected patients with severe ischemic left ventricular dysfunction and predominance of tissue viability, coronary artery bypass grafting may be capable of implement preoperative clinical/functional parameters in predicting outcome as left ventricular ejection fraction and gated left ventricular ejection fraction at exercise/rest.

Surgical myocardial revascularization of patients with ischemic cardiomyopathy and severe left ventricular disfunction

Objective: To determine long-term survival, identify preoperative factors predictive of a favorable outcome, and assess functional improvement after coronary artery bypass grafting in patients with advanced left ventricular dysfunction. Methods: Between 1995 and 2001, 244 patients who underwent coronary artery bypass grafting and had a preoperative left ventricular ejection fraction less than or equal to 35 percent were included. left ventricular ejection fraction was determined by uniplanar or biplanar ventriculography during left heart catheterization. Indication for surgery was predominance of tissue viability. Functional improvement was evaluated through echocardiography and gated scintigraphy at exercise/ rest. Survival was determined by Kaplan-Meier analysis. Results: Mean left ventricular ejection fraction was 29±4 percent (ranged from 9 percent to 35 percent). An average of 3.01 coronary bypass grafts per patient were performed. In-hospital mortality was 3.7 percent (9 patients). The 4-year survival rate was 89.7 percent. Multivariate correlates of favorable short- and long-term outcome were preoperative New York Heart Association Funcional classification for congestive heart failure class I/II, lower PAsP, higher left ventricular ejection fraction and gated left ventricular ejection fraction Ex/Rest ratio >5 percent. Left ventricular ejection fraction rise from 32±5 percent to 39±5 percent, p <0.001. Gated left ventricular ejection fraction at exercise/ rest increased markedly after surgery: from 27±8 percent/ 23±7 percent to 37±5 percent/ 31±6 percent, p <0.001. Conclusions: In selected patients with severe ischemic left ventricular dysfunction and predominance of tissue viability, coronary artery bypass grafting may be capable of implement preoperative clinical/ functional parameters in predicting outcome as left ventricular ejection fraction and gated left ventricular ejection fraction at exercise/ rest.

Validation of a treadmill six-minute walk test protocol for the evaluation of patients with pulmonary arterial hypertension.

OBJECTIVE: To develop and validate a protocol for the treadmill six-minute walk test (tread6MWT) to evaluate patients with pulmonary arterial hypertension (PAH). METHODS: The study population comprised 73 patients with PAH, diagnosed by means of right heart catheterization, with or without NO inhalation. All patients performed a hallway 6MWT and three tread6MWTs based on a pre-determined incremental speed protocol and interposed by a rest period. The patients who had been submitted to hemodynamic testing using NO performed the third tread6MWT while inhaling the same dose of NO that had been used during the catheterization. RESULTS: We found that the treadmill six-minute walk distance (tread6MWD) correlated with hemodynamic data, functional class and the hallway six-minute walk distance (6MWD). In addition, the tread6MWD correlated significantly with survival, thereby confirming the correlation with disease severity. Inhalation of NO during the tread6MWT led to variations that were consistent with the hemodynamic changes induced by the same dose of inhaled NO, suggesting that the protocol developed can reflect the effect of therapeutic interventions. CONCLUSIONS: We conclude that the tread6MWD is a useful prognostic and functional marker for the routine evaluation of PAH patients.

Validação de um protocolo para o teste de caminhada de seis minutos em esteira para avaliação de pacientes com hipertensão arterial pulmonar / Validation of a treadmill six-minute walk test protocol for the evaluation of patients with pulmonary arterial hypertension

OBJETIVO: Elaborar e validar um protocolo para teste de caminhada de seis minutos em esteira (TC6est) para a avaliação de pacientes com hipertensão arterial pulmonar (HAP). MÉTODOS: A população do estudo foi composta por 73 pacientes com HAP diagnosticados através de cateterismo cardíaco direito, com ou sem inalação de NO. Todos os pacientes realizaram um TC6 em solo e três TC6est baseados em um protocolo de incremento de velocidade pré-determinado e intercalados por um período de repouso. Os pacientes que haviam realizado o teste hemodinâmico com inalação de NO realizaram o terceiro TC6est com a inalação da mesma dose de NO utilizada durante o cateterismo. RESULTADOS: Os resultados mostraram uma correlação da distância caminhada no TC6est com os dados hemodinâmicos, assim como com a classe funcional e com a distância caminhada no solo. Além disso, a distância percorrida no TC6est apresentou uma correlação significativa com a sobrevida, confirmando, portanto, sua correlação com a gravidade da doença. A inalação de NO durante o TC6est levou a variações compatíveis com as variações hemodinâmicas frente à mesma dose de NO, sugerindo que o protocolo em questão pode refletir o efeito de intervenções terapêuticas. CONCLUSÕES: Concluímos que a distância percorrida no TC6est é um marcador funcional e prognóstico na avaliação de rotina de pacientes com HAP.

OBJECTIVE: To develop and validate a protocol for the treadmill six-minute walk test (tread6MWT) to evaluate patients with pulmonary arterial hypertension (PAH). METHODS:The study population comprised 73 patients with PAH, diagnosed by means of right heart catheterization, with or without NO inhalation. All patients performed a hallway 6MWT and three tread6MWTs based on a pre-determined incremental speed protocol and interposed by a rest period. The patients who had been submitted to hemodynamic testing using NO performed the third tread6MWT while inhaling the same dose of NO that had been used during the catheterization. RESULTS: We found that the treadmill six-minute walk distance (tread6MWD) correlated with hemodynamic data, functional class and the hallway six-minute walk distance (6MWD). In addition, the tread6MWD correlated significantly with survival, thereby confirming the correlation with disease severity. Inhalation of NO during the tread6MWT led to variations that were consistent with the hemodynamic changes induced by the same dose of inhaled NO, suggesting that the protocol developed can reflect the effect of therapeutic interventions. CONCLUSIONS: We conclude that the tread6MWD is a useful prognostic and functional marker for the routine evaluation of PAH patients.

Pulmonary veno-occlusive disease: diagnostic and therapeutic alternatives.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary hypertension. Surgical biopsy was usually required for diagnostic confirmation. However, the morbidity, mortality and limited benefit of this procedure have generated discussion regarding noninvasive diagnostic techniques. We present the case of a female patient with progressive dyspnea, hypoxemia and pulmonary hypertension, the last diagnosed via catheterization. Computed tomography revealed septal thickening and diffuse micronodules. Bronchoalveolar lavage revealed occult alveolar hemorrhage. Treatment with an endothelin antagonist was started, resulting in symptomatic and functional improvement. Occult alveolar hemorrhage differentiates PVOD from idiopathic pulmonary hypertension. We believe that this finding, in combination with characteristic tomographic findings, is sufficient to establish a diagnosis of PVOD.

Doença veno-oclusiva pulmonar: alternativas diagnósticas e terapêuticas / Pulmonary veno-occlusive disease: diagnostic and therapeutic alternatives

A doença veno-oclusiva pulmonar (DVOP) é uma causa rara de hipertensão pulmonar. A biópsia cirúrgica era usualmente necessária para seu diagnóstico; entretanto, sua morbidade, mortalidade e seu impacto limitado levantou a discussão sobre o diagnóstico não-invasivo. Apresentamos um caso de uma paciente com dispnéia progressiva, hipoxemia e hipertensão pulmonar no cateterismo. A tomografia computadorizada revelou espessamento septal e micronódulos difusos. O lavado broncoalveolar revelou hemorragia alveolar oculta. Iniciou-se tratamento com antagonista da endotelina, que resultou em melhora clínica e funcional. A hemorragia alveolar oculta é uma característica da DVOP capaz de diferenciá-la da hipertensão pulmonar idiopática. Acreditamos que sua presença, associada à tomografia característica, seja suficiente para o diagnóstico de DVOP.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary hypertension. Surgical biopsy was usually required for diagnostic confirmation. However, the morbidity, mortality and limited benefit of this procedure have generated discussion regarding noninvasive diagnostic techniques. We present the case of a female patient with progressive dyspnea, hypoxemia and pulmonary hypertension, the last diagnosed via catheterization. Computed tomography revealed septal thickening and diffuse micronodules. Bronchoalveolar lavage revealed occult alveolar hemorrhage. Treatment with an endothelin antagonist was started, resulting in symptomatic and functional improvement. Occult alveolar hemorrhage differentiates PVOD from idiopathic pulmonary hypertension. We believe that this finding, in combination with characteristic tomographic findings, is sufficient to establish a diagnosis of PVOD.

Post-mortem histological pulmonary analysis in patients with HIV/AIDS.

OBJECTIVES: Certain aspects of pulmonary pathology observed in autopsies of HIV/AIDS patients are still unknown. This study considers 250 autopsies of HIV/AIDS patients who died of acute respiratory failure and describes the demographic data, etiology, and histological pulmonary findings of the various pathologies. METHODS: The following data were obtained: age, sex, and major associated diseases (found at the autopsy). Pulmonary histopathology was categorized as: diffuse alveolar damage; pulmonary edema; alveolar hemorrhage; and acute interstitial pneumonia. Odds ratio of the HIV/AIDS-associated diseases developing a specific histopathological pattern was determined by logistic regression. RESULTS: A total of 197 men and 53 women were studied. The mean age was 36 years. Bacterial bronchopneumonia was present in 36% (91 cases) and Pneumocystis jiroveci pneumonia in 27% (68) of patients. Pulmonary histopathology showed acute interstitial pneumonia in 40% (99), diffuse alveolar damage in 36% (89), pulmonary edema in 13% (33), and alveolar hemorrhage in 12% (29) of patients. Multivariate analysis showed a significant and positive association between Pneumocystis jiroveci pneumonia and acute interstitial pneumonia (Odds ratio, 4.51; 95% CI, 2.46-8.24; p<0.001), severe sepsis and/or septic shock and diffuse alveolar damage (Odds ratio, 3.60; 95% CI, 1.78-7.27; p<0.001), and cytomegalovirus and acute interstitial pneumonia (Odds ratio, 2.22; 95% CI, 1.01-4.93; p=0.05). CONCLUSIONS: This report is the first autopsy study to include demographic data, etiologic diagnosis, and respective histopathological findings in patients with HIV/AIDS and acute respiratory failure. Further studies are necessary to elucidate the complete pulmonary physiopathological mechanism involved with each HIV/AIDS-associated disease.

[Chronic thromboembolic pulmonary hypertension: diagnostic limitations]. / Hipertensão pulmonar associada ao tromboembolismo pulmonar crônico: limitações diagnósticas.

Chronic thromboembolic pulmonary hypertension is the only potentially curable form of pulmonary hypertension, assuming that surgical treatment is possible. However, there are hindrances to making a definitive, noninvasive diagnosis. We present the case of a 40-year-old female patient with idiopathic pulmonary arterial hypertension, confirmed in 1994. This patient developed thrombi in pulmonary vessels (as an overlap syndrome) mimicking chronic thromboembolic pulmonary hypertension. The identification of these conditions, which present high intraoperative mortality and unsatisfactory surgical resolution, is quite difficult in clinical practice. We discuss the current approach to candidate selection for surgical treatment of chronic thromboembolic pulmonary hypertension and the possible repercussions of inappropriate selection.

Hipertensão pulmonar associada ao tromboembolismo pulmonar crônico: limitações diagnósticas / Chronic thromboembolic pulmonary hypertension: diagnostic limitations

A hipertensão pulmonar associada ao tromboembolismo pulmonar crônico é a única forma potencialmente curável de hipertensão pulmonar, desde que o tratamento cirúrgico seja possível. Existem, entretanto, limitações para o diagnóstico não-invasivo definitivo. Apresentamos o caso de uma paciente de 40 anos, com diagnóstico confirmado de hipertensão arterial pulmonar idiopática desde 1994, a qual evoluiu com sobreposição de trombos em vasos pulmonares simulando hipertensão pulmonar associada ao tromboembolismo pulmonar crônico. O reconhecimento dessas condições, as quais apresentam alta mortalidade intra-operatória e baixa resolutividade cirúrgica, é muito difícil na prática clínica. Discutiremos a abordagem atual para a seleção de candidatos para o tratamento cirúrgico da hipertensão pulmonar associada ao tromboembolismo pulmonar crônico e as possíveis repercussões da seleção inadequada.

Chronic thromboembolic pulmonary hypertension is the only potentially curable form of pulmonary hypertension, assuming that surgical treatment is possible. However, there are hindrances to making a definitive, noninvasive diagnosis. We present the case of a 40-year-old female patient with idiopathic pulmonary arterial hypertension, confirmed in 1994. This patient developed thrombi in pulmonary vessels (as an overlap syndrome) mimicking chronic thromboembolic pulmonary hypertension. The identification of these conditions, which present high intraoperative mortality and unsatisfactory surgical resolution, is quite difficult in clinical practice. We discuss the current approach to candidate selection for surgical treatment of chronic thromboembolic pulmonary hypertension and the possible repercussions of inappropriate selection.

Post-mortem histological pulmonary analysis in patients with HIV/AIDS

OBJECTIVES: Certain aspects of pulmonary pathology observed in autopsies of HIV/AIDS patients are still unknown. This study considers 250 autopsies of HIV/AIDS patients who died of acute respiratory failure and describes the demographic data, etiology, and histological pulmonary findings of the various pathologies. METHODS: The following data were obtained: age, sex, and major associated diseases (found at the autopsy). Pulmonary histopathology was categorized as: diffuse alveolar damage; pulmonary edema; alveolar hemorrhage; and acute interstitial pneumonia. Odds ratio of the HIV/AIDS-associated diseases developing a specific histopathological pattern was determined by logistic regression. RESULTS: A total of 197 men and 53 women were studied. The mean age was 36 years. Bacterial bronchopneumonia was present in 36 percent (91 cases) and Pneumocystis jiroveci pneumonia in 27 percent (68) of patients. Pulmonary histopathology showed acute interstitial pneumonia in 40 percent (99), diffuse alveolar damage in 36 percent (89), pulmonary edema in 13 percent (33), and alveolar hemorrhage in 12 percent (29) of patients. Multivariate analysis showed a significant and positive association between Pneumocystis jiroveci pneumonia and acute interstitial pneumonia (Odds ratio, 4.51; 95 percent CI, 2.46 - 8.24; p < 0.001), severe sepsis and/or septic shock and diffuse alveolar damage (Odds ratio, 3.60; 95 percent CI, 1.78 -7.27; p < 0.001), and cytomegalovirus and acute interstitial pneumonia (Odds ratio, 2.22; 95 percent CI, 1.01 - 4.93; p = 0.05). CONCLUSIONS: This report is the first autopsy study to include demographic data, etiologic diagnosis, and respective histopathological findings in patients with HIV/AIDS and acute respiratory failure. Further studies are necessary to elucidate the complete pulmonary physiopathological mechanism involved with each HIV/AIDS-associated disease.