New research was presented at ATS 2021, the American Thoracic Society International Conference, held May 15-18 in San Francisco. The features below highlight some of the studies that emerged from the conference.
Sleep Apnea Found in Most Children With Pulmonary Hypertension
Most pediatric patients with pulmonary hypertension (PH) are affected by obstructive sleep apnea (OSA), suggesting that routine screening for OSA in this population is warranted, according to Daniel A. Ignatiuk, MD, who presented a retrospective study analyzing OSA risk factors reported in a 10-year investigation of pediatric patients with PH who underwent diagnostic polysomnogram. These patients were sub-classified based on their PH group: group 1 (28.1%), group 3 (34.8%), and group 1/3 for patients meeting both group 1 and 3 criteria (37.1%). Diagnosed sleep disorders included OSA (88.8%), central sleep apnea (12.4%), non-apneic hypoxemia (31.5%), hypoventilation (6.7%), and periodic limb movement disorder (5.6%). Risk for OSA was increased with a diagnosis of trisomy 21 (RR, 1.24; 95% CI, 1.09-1.42). However, OSA risk was decreased in group 1 compared with group 1/3 PH (RR, 0.84; 95% CI, 0.71-0.9) or group 3 PH (RR, 0.81; 95% CI, 0.68-0.96). No difference in OSA risk between group 1 and group 3 PH was observed. The takeaway message is that OSA was diagnosed in a majority of pediatric patients, most notably in patients with trisomy 21 or PH classification meeting both group 1 and 3 criteria. “Our research supports routine screening for OSA in this population,” said Dr. Ignatiuk.
Good Outcomes With Lung Transplantation for COVID-19-Associated ARDS
For carefully selected patients with severe COVID-19-associated acute respiratory distress syndrome (ARDS) among whom lung transplantation is the only option for survival, the procedure can be performed successfully, with good early post-transplantation outcomes. G.R. Scott Budinger, MD, presented data based on patients with COVID-19 at imminent risk of dying from ARDS who had received lung transplants. “Patients with COVID-19-associated ARDS who received lung transplants had similar outcomes when compared with transplant patients without COVID-19, despite modestly increased early post-op complications,” said Dr. Budinger. A retrospective study focused on a case series of 102 patients who underwent a lung transplant at Northwestern Memorial Hospital between January 2020 and September 2021, including 30 patients with COVID-19-associated ARDS. Although rates of transplant complications and length of ICU stays were both higher in the COVID-19 group, patient survival in both groups was not considerably different. Overall, this data was very similar to that of other studies. Dr. Budinger pointed out that this finding is encouraging for the treatment of patients with COVID-19 who have no other options. Furthermore, the collective data can reassure the community that precious resources, such as donor lungs, will not necessarily have poorer outcomes in candidates with COVID-19.
In Patients With Morbid Obesity, CPAP Supports Pulmonary Oxygenation
In patients with morbid obesity with normal lung function, post-extubation CPAP achieved improved pulmonary oxygenation, according to results from a prospective, randomized controlled trial. Felix Girrbach, MD, explained that mechanical ventilation with individualized positive end-expiratory pressure (PEEPIND), in combination with continuous CPAP support in the initial hours following extubation, is linked with better oxygenation compared with the use of PEEP alone. For the study, patients with a BMI greater than 35 kg/m2 who were due to undergo bariatric laparoscopic abdominal surgery were ventilated with PEEPIND—defined as “the PEEP value with the lowest regional ventilation inhomogeneity as determined by electrical impedance tomography during a standardized decremental PEEP-trial”—and randomized to CPAP or a control group. Baseline characteristics were similar in both groups, with a mean age of 44 and a mean BMI of 46.9 kg/m2. Participants in the CPAP group received continuous CPAP support for 2 hours after extubation, compared with standard supportive care for those in the control group. Arterial oxygen partial pressure (PaO2)/fractional inspired oxygen (FiO2) ratio was measured 2 and 4 hours after extubation. There was no difference between the groups with regard to the median PEEPIND, which was roughly 18 cmH2O in both groups. However, although oxygenation (PaO2/FiO2 ratio) prior to extubation was comparable between the groups, the PaO2/FiO2 ratio in the CPAP group was significantly higher during CPAP support (472 mmHg in the intervention arm vs 317 mmHg in the control arm). Dr. Girrbach suggested that despite post-extubation CPAP support in patients with morbid obesity with normal lung function, the improvement in oxygenation did not persist after termination of CPAP support, potentially pointing to atelectasis formation.
Screening Asymptomatic Adults for COPD Not Necessary
Asymptomatic adults should not be screened for COPD, according to the USPSTF, based on evidence that there was no net benefit. Since COPD is the sixth leading cause of death in the United States, the USPSTF re-evaluated screening evidence of asymptomatic individuals, after its original recommendation against screening in asymptomatic adults was issued in 2016. Carol M. Mangione, MD, presented these results and recommendations. After reviewing of all new evidence, the USPSTF re-affirms their previous recommendation that COPD civilian screening has no net benefit for asymptomatic adults. The Task Force stresses that the recommendation only applies to adults with no respiratory symptoms; anyone with symptoms, such as a chronic cough, sputum, breathing difficulties, or wheezing, should consult a specialist and take action. The USPSTF added that factors such as cigarette smoking could increase an individual’s risk for COPD, as cigarette smoking is the leading cause of COPD in the US, with approximately 15% of current smokers and 8% of former smokers reporting a COPD diagnosis. The Task Force reviewed new data from six treatment trials and two observational trials focusing on pharmacologic or non-pharmacologic treatment harms in adults with mild to moderate or minimally symptomatic COPD. Among the trials that reported adverse events, no significant harms were recorded, the researchers noted, adding that it’s still unclear whether early treatment for asymptomatic, minimally symptomatic, or screen-detected populations would slow disease progression. “The USPSTF found no new substantial evidence that could change its recommendation and, therefore, re-affirms its recommendation against screening for COPD in asymptomatic adults,” Dr. Mangione said.
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