In 2009, during the influenza A (H1N1) epidemic, there were many reported cases of pulmonary infection with severe hypoxemia that was refractory to the ventilatory strategies and rescue therapies commonly used to treat patients with severe acute respiratory distress syndrome. Many of those cases were treated with extracorporeal membrane oxygenation (ECMO), which renewed international interest in the technique. The Extracorporeal Support Study Group was created in order to practice ECMO and to employ it in the treatment of patients with severe hypoxemia. In this article, we discuss the indications for using ECMO and report the case of a patient with refractory hypoxemia who was successfully treated with ECMO.

Keywords: : Respiratory Insufficiency; Intensive Care Units; Extracorporeal Membrane Oxygenation.

The world has been suffering from the COVID-19 pandemic. Some COVID-19 patients develop severe viral pneumonia, requiring mechanical ventilation and measures to treat refractory hypoxemia, such as a protective ventilation strategy, prone positioning, and the use of veno-venous extracorporeal membrane oxygenation (VV-ECMO). We describe a case series of 30 COVID-19 patients who needed VV-ECMO at the Hospital Alemão Oswaldo Cruz, located in the city of São Paulo, Brazil. Methods: We included all patients who required VV-ECMO due to COVID-19 pneumonia between March of 2020 and June of 2021. Results: Prior to VV-ECMO, patients presented with the following median scores: SOFA score, 11; APPS score, 7; Respiratory ECMO Survival Prediction score, 2; and Murray score, 3.3. The 60-day-in-hospital mortality was 33.3% (n = 10). Conclusions: Although our patients had a highly severe profile, our results were similar to those of other cohort studies in the literature. This demonstrates that VV-ECMO can be a good tool even in a pandemic situation when it is managed in an experienced center.

Keywords: Extracorporeal membrane oxygenation; COVID-19; SARS-CoV-2; Respiratory distress syndrome.

In patients with severe respiratory failure, either hypoxemic or hypercapnic, life support with mechanical ventilation alone can be insufficient to meet their needs, especially if one tries to avoid ventilator settings that can cause injury to the lungs. In those patients, extracorporeal membrane oxygenation (ECMO), which is also very effective in removing carbon dioxide from the blood, can provide life support, allowing the application of protective lung ventilation. In this review article, we aim to explore some of the most relevant aspects of using ECMO for respiratory support. We discuss the history of respiratory support using ECMO in adults, as well as the clinical evidence; costs; indications; installation of the equipment; ventilator settings; daily care of the patient and the system; common troubleshooting; weaning; and discontinuation.

Keywords: Extracorporeal membrane oxygenation; Respiratory distress syndrome, adult; Hypoxia; Hypercapnia.

Objective: To determine the prevalence of nocturnal hypoxemia and its association with pulmonary function, nutritional status, sleep macrostructure, and obstructive respiratory events during sleep in a population of clinically stable children and adolescents with cystic fibrosis (CF). Methods: This was a cross-sectional study involving 67 children and adolescents with CF between 2 and 14 years of age. All of the participants underwent polysomnography, and SpO2 was measured by pulse oximetry. We also evaluated the Shwachman-Kulczycki (S-K) scores, spirometry findings, and nutritional status of the patients. Results: The study involved 67 patients. The mean age of the patients was 8 years. The S-K scores differed significantly between the patients with and without nocturnal hypoxemia, which was defined as an SpO2 < 90% for more than 5% of the total sleep time (73.75  6.29 vs. 86.38  8.70; p < 0.01). Nocturnal hypoxemia correlated with the severity of lung disease, FEV1 (rs = −0.42; p = 0.01), FVC (rs = −0.46; p = 0.01), microarousal index (rs = 0.32; p = 0.01), and apnea-hypopnea index (rs = 0.56; p = 0.01). Conclusions: In this sample of patients with CF and mild-to-moderate lung disease, nocturnal oxygenation correlated with the S-K score, spirometry variables, sleep macrostructure variables, and the apnea-hypopnea index.

Keywords: Cystic fibrosis; Sleep; Oximetry.

Objective: To verify association between left ventricular (LV) mass and thickness and the presence of significant nocturnal hypoxemia in patients with COPD with mild diurnal hypoxemia. Methods: A cross-sectional study carried out in clinically stable outpatients with COPD and mild hypoxemia (oxygen saturation ≥90 to ≤94%, identified by noninvasive oximetry) in a clinic specialized in the treatment of respiratory diseases in Goiânia-GO. All patients were submitted to clinical evaluation, spirometry, polysomnography, echocardiography, arterial blood gas analysis, 6-minute walk test and chest X-ray. Results: Patients with significant nocturnal hypoxemia had echocardiographic parameters associated with increase of LV musculature when compared to patients with mild nocturnal hypoxemia. The LV volume/mass ratio was significantly lower in the group with significant nocturnal hypoxemia (ratio 0.64 ± 0.13 versus 0.72 ± 0.12, p = 0.04), the thickness diastolic diameter of the interventricular septum and the diastolic thickness of the LV posterior wall were significantly higher in this group (9.7 ± 0.92 versus 9.1 ± 0.90 p = 0.03), (9.7 ± 1.0 versus 8.9 ± 1.0, p = 0.01. The time in REM sleep with saturation below 85% significantly predicted septum thickness (adjustment for BMI, age and mean blood pressure, r2 = 0.20; p = 0.046). Conclusion: We observed association between severe REM sleep hypoxemia and echocardiographic parameters indicating increased LV mass in individuals with COPD and significant nocturnal hypoxemia. This suggests that this subgroup of individuals may benefit from an echocardiographic evaluation of the left ventricle.

Keywords: Chronic Obstructive Pulmonary Disease; Left ventricular hypertrophy; Echocardiography.

Objective: To infer the prevalence and variables predictive of isolated nocturnal hypoxemia and obstructive sleep apnea (OSA) in patients with COPD and mild hypoxemia. Methods: This was a cross-sectional study involving clinically stable COPD outpatients with mild hypoxemia (oxygen saturation = 90-94%) at a clinical center specializing in respiratory diseases, located in the city of Goiânia, Brazil. The patients underwent clinical evaluation, spirometry, polysomnography, echocardiography, arterial blood gas analysis, six-minute walk test assessment, and chest X-ray. Results: The sample included 64 patients with COPD and mild hypoxemia; 39 (61%) were diagnosed with sleep-disordered breathing (OSA, in 14; and isolated nocturnal hypoxemia, in 25). Correlation analysis showed that PaO2 correlated moderately with mean sleep oxygen saturation (r = 0.45; p = 0.0002), mean rapid eye movement (REM) sleep oxygen saturation (r = 0.43; p = 0.001), and mean non-REM sleep oxygen saturation (r = 0.42; p = 0.001). A cut-off point of PaO2 ≤ 70 mmHg in the arterial blood gas analysis was significantly associated with sleep-disordered breathing (OR = 4.59; 95% CI: 1.54-13.67; p = 0.01). The model showed that, for identifying sleep-disordered breathing, the cut-off point had a specificity of 73.9% (95% CI: 51.6-89.8%), a sensitivity of 63.4% (95% CI: 46.9-77.9%), a positive predictive value of 81.3% (95% CI: 67.7-90.0%), and a negative predictive value of 53.1% (95% CI: 41.4-64.4%), with an area under the ROC curve of 0.69 (95% CI: 0.57-0.80), correctly classifying the observations in 67.2% of the cases. Conclusions: In our sample of patients with COPD and mild hypoxemia, the prevalence of sleep-disordered breathing was high (61%), suggesting that such patients would benefit from sleep studies.

Keywords: Pulmonary disease, chronic obstructive/complications; Sleep wake disorders/epidemiology; Anoxia/etiology.

Objective: To study the effects of nocturnal hypoxemia in patients with chronic obstructive pulmonary disease without obstructive sleep apnea syndrome. Methods: We studied 21 patients-10 desaturators and 11 nondesaturators-submitted to arterial blood gas analysis, polysomnography, spirometry, cardiopulmonary exercise testing (cycle ergometer), and hand-grip dynamometry, as well as measurements of maximal inspiratory pressure, maximal expiratory pressure, and C-reactive protein (CRP) levels. Patients with arterial oxygen tension > 60 mmHg were included; those with an apnea-hypopnea index > 5 events/hour of sleep were excluded. Maximal oxygen uptake, maximal power, systolic blood pressure, diastolic blood pressure (DBP), and maximal heart rate were measured during exercise in order to detect hemodynamic alterations. Patients presenting CRP levels above 3 mg/L were considered CRP-positive. Results: Minimal peripheral oxygen saturation during sleep was significantly higher among nondesaturators (p = 0.03). More desaturators presented CRP > 3 mg/L (p < 0.05). No differences were observed in terms of any variables, However, mean peripheral oxygen saturation during sleep correlated with DBP and maximal inspiratory pressure (p < 0.001 and p = 0.001, respectively). Conclusions: Although nocturnal hypoxemia does not reduce exercise capacity or hand-grip strength in patients with mild/moderate COPD, its effect on maximal exercise DBP seems to depend on the degree of hypoxemia. In addition, there is a positive relationship between maximal inspiratory pressure and mean peripheral oxygen saturation during sleep, as well as evidence of pronounced inflammatory activation in patients with nocturnal hypoxemia.

Keywords: Pulmonary disease, chronic obstructive; Exercise test; Anoxia; Respiratory function tests.