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The coronavirus disease 2019 (COVID-19) pandemic upended our approach to imaging community-acquired pneumonia, and this will alter our diagnostic algorithms for years to come. In light of these changes, it is worthwhile to consider several postpandemic scenarios of community-acquired pneumonia: (1) patient with pneumonia and recent positive COVID-19 testing; (2) patient with air space opacities and history of prior COVID-19 pneumonia (weeks earlier); (3) multifocal pneumonia with negative or unknown COVID-19 status; and (4) lobar or sublobar pneumonia with negative or unknown COVID-19 status. In the setting of positive COVID-19 testing and typical radiologic findings, the diagnosis of COVID-19 pneumonia is generally secure. The diagnosis prompts vigilance for thromboembolic disease acutely and, in severely ill patients, for invasive fungal disease. Persistent or recurrent air space opacities following COVID-19 infection may more often represent organizing pneumonia than secondary infection. When COVID-19 status is unknown or negative, widespread airway-centric disease suggests infection with mycoplasma, Haemophilus influenzae, or several respiratory viruses. Necrotizing pneumonia favors infection with pneumococcus, Staphylococcus , Klebsiella , and anaerobes. Lobar or sublobar pneumonia will continue to suggest the diagnosis of pneumococcus or consideration of other pathogens in the setting of local outbreaks. A positive COVID-19 test accompanied by these imaging patterns may suggest coinfection with one of the above pathogens, or when the prevalence of COVID-19 is very low, a false positive COVID-19 test. Clinicians may still proceed with testing for COVID-19 when radiologic patterns are atypical for COVID-19, dependent on the patient's exposure history and the local epidemiology of the virus., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: The precision and accuracy of self-measured peak expiratory flow rates (PEFR) have not been determined for patients with chronic obstructive pulmonary disease (COPD)., Methods: Twenty-eight male veterans recorded their PEFR twice daily, before and after bronchodilators, for 6 months. Spirometry was also done in the pulmonary function laboratory up to 11 times per patient during the observation period. A 4-week "baseline" was identified for each patient. Baseline coefficients of variation (CV) were calculated for the morning (AM) and evening (PM) PEFR, before (PRE) and after (POST) bronchodilators., Results: The baseline CVs for AMPRE, AMPOST, PMPRE and PMPOST were 14.9+/-6.9%, 12.6+/-5.6%, 14.9+/-4.8%, and 11.2+/-6.0%, respectively. There were strong correlations between self-measured PEFR and values obtained in the pulmonary function laboratory on the same day., Conclusions: Self-measured PFFRs are reasonably precise and accurate in patients with COPD.

The aim of this study was to look at changes in peak expiratory flow rates (PEFR) prior to emergency department visits for decompensated chronic obstructive pulmonary disease (COPD). It was designed as a prospective, double-blind study at the Albuquerque Veterans Affairs Medical Center. Twelve patients with an irreversible component of airflow obstruction on pulmonary function tests were assessed. At entry, all subjects were instructed in the use of a mini-Wright peak flow meter with electronic data storage. They then entered a 6-month monitoring phase in which they recorded PEFR twice daily, before and after bronchodilators. The meter displays were disabled so that the patients and their physicians were blinded to all values. Medical care was provided in the customary manner. Patients were considered to have respiratory decompensation if they required treatment for airflow obstruction in the Emergency Department (ED) and no other causes of dyspnea could be identified. Simple linear regression was used to model changes in PEFR over time. The 12 subjects had 22 episodes of respiratory decompensation during 1741 patient-days of observation. Two episodes could not be analysed because of missing values. Ten episodes in seven subjects were characterized by a significant linear decline in at least one peak flow parameter prior to presentation. The mean rates of change for the four daily parameters varied from 0.22% to 0.27% predicted per day (or 1.19 to 1.44 1 min-1 day-1). The average decrement in these parameters ranged from 30.0 to 33.8 1 min-1 (or 18.6%-25.9% of their baseline values). No temporal trends were found for the 10 episodes occurring in the other five subjects. We concluded that respiratory decompensation is characterized by a gradual decline in PEFR in about half of cases. Future studies should be done to elucidate the mechanisms of respiratory distress in the other cases.

Objective: To develop and validate a multivariate model for predicting respiratory status in patients with advanced chronic obstructive pulmonary disease (COPD)., Design: Prospective, double-blind study of peak flow monitoring., Setting: Albuquerque Veterans Affairs Medical Center., Patients: Male veterans with an irreversible component of airflow obstruction on baseline pulmonary function tests., Measurements: This study was conducted between January 1995 and May 1996. At entry, subjects were instructed in the use of the modified Medical Research Council Dyspnea Scale and a mini-Wright peak flow meter equipped with electronic storage. For the next 6 months, they recorded their dyspnea scores once daily and peak expiratory flow rates twice daily, before and after the use of bronchodilators. Patients were blinded to their peak expiratory flow rates, and medical care was provided in the customary manner. Readings were aggregated into 7-day sampling intervals, and interval means were calculated for dyspnea score and peak expiratory flow rate parameters. Intervals from all subjects were then pooled and randomized to separate groups for model development (training set) and validation (test set). In the training set, logistic regression was used to identify variables that predicted future respiratory status. The dependent variable was the log odds that the subject would attain his highest level of dyspnea in the next 7 days. The final model was used to stratify the test set into "high-risk" and "low-risk" categories. The analysis was repeated for 3-day intervals., Main Results: Of the 40 patients considered eligible for study, 8 declined to participate, 4 could not master the technique of peak flow monitoring, and 6 had no fluctuations in their dyspnea level. The remaining 22 subjects form the basis of this report. Fourteen (64%) of the latter completed the 6-month protocol. Data from the 8 who were dropped or died were included up to the point of withdrawal. For 7-day forecasts, mean dyspnea score and mean daily prebronchodilator peak expiratory flow rate were identified as predictor variables. The adjusted odds ratio (OR) for mean dyspnea score was 2.71 (95% confidence interval [CI] 1.79, 4.12) per unit. For mean prebronchodilator peak expiratory flow rate, it was 1.05 (95% CI 1.01, 1.09) per percentage predicted. For 3-day forecasts, the model was composed of mean dyspnea score and mean daily bronchodilator response. The ORs for these terms were 2.66 (95% CI 2.06, 3.44) per unit and 0.980 (95% CI 0.962, 0.998) per percentage of improvement over baseline, respectively. For a given level of dyspnea, higher pre-bronchodilator peak expiratory flow rate and lower bronchodilator response were poor prognostic findings. When the models were applied to the test sets, "high-risk" intervals were 4 times more likely to be followed by maximal symptoms than "low-risk" intervals., Conclusions: Dyspnea scores and certain peak expiratory flow rate parameters are independent predictors of respiratory status in patients with COPD. However, our results suggest that monitoring is of little benefit except in patients with the most advanced form of this disease, and its contribution to their management is modest at best.

Background: The factors affecting patient compliance with peak flow monitoring in advanced chronic obstructive pulmonary disease (COPD) were examined using a prospective, blinded study., Methods: Twenty-eight male veterans were instructed in the use of an electronic, hand-held peak flow meter and the modified Medical Research Council dyspnea scale. They then entered a 6-month monitoring phase in which they recorded a dyspnea score once daily and peak expiratory flow rates twice daily, before and after bronchodilator use. The meter displays were disabled so that the patients were blinded to their values. Medical care was provided in the customary manner. Compliance was defined as the ratio of recorded values to all values specified by the protocol, exclusive of those missing due to circumstances beyond the patient's control., Results: Of 40 patients who met the entry criteria for this study, 8 refused to participate and 4 could not master the technique. The remaining 28 patients were enrolled. Overall, 25 (63% of those eligible) adhered to the protocol until its conclusion or until they became unable to comply because of medical or social problems. Compliance was 89.8+/-15.0%. Of those followed for longer than 150 days, linear regression showed that only one patient had a decline in compliance over time (r=0.84, P=0.04). Compliance was lower in the afternoons (P < 0.001) and on days with higher dyspnea scores (P < 0.001). No other clinical factors had an effect on patient measurements., Conclusions: A substantial proportion of patients with advanced COPD can be trained in the technique of peak flow monitoring. Compliance is high if patients are enrolled in a long-term, structured program of supervision and periodic retraining.

To investigate the potential role of transforming growth factor-alpha (TGF-alpha) and the epidermal growth factor receptor (EGF-R) in the fibroproliferative response to acute lung injury, we determined lung steady-state TGF-alpha and EGF-R mRNA levels, TGF-alpha protein levels, and the distribution of TGF-alpha and EGF-R immunoreactive protein of bleomycin-injured and control rat lungs. At 2 and 4 days after a single intratracheal injection of bleomycin, TGF-alpha mRNA levels increased to 159% and 184% of control values, respectively. EGF-R mRNA levels increased to 163%, 314%, and 170% of control values at 1, 7, and 14 days after bleomycin instillation. TGF-alpha protein levels in whole lung extracts increased to 230% of control values at 4 days after bleomycin administration. TGF-alpha and EGF-R immunoreactivity was detected in macrophages, alveolar septal cells, and airway epithelium of control and bleomycin-injured animals with an apparent increase in the intensity and number of specifically immunostained cells following lung injury. TGF-alpha and EGF-R immunoreactive proteins were detected in foci of cellular proliferation and in areas of intraalveolar fibrosis. We conclude that TGF-alpha and the EGF-R are present in normal and bleomycin-injured rat lung and that the expression of this growth factor and its receptor are up-regulated following lung injury. These results suggest that increased expression of TGF-alpha and the EGF-R may be an important mechanism that modulates the fibroproliferative response to acute lung injury.