Background The utility of heated and humidified high-flow nasal oxygen (HFNO) for severe COVID-19-related hypoxaemic respiratory failure (HRF), particularly in s``ettings with limited access to intensive care unit (ICU) resources, remains unclear, and predictors of outcome have been poorly studied. Methods We included consecutive patients with COVID-19-related HRF treated with HFNO at two tertiary hospitals in Cape Town, South Africa. The primary outcome was the proportion of patients who were successfully weaned from HFNO, whilst failure comprised intubation or death on HFNO. Findings The median (IQR) arterial oxygen partial pressure to fraction inspired oxygen ratio (P a O2/FiO 2 ) was 68 (54–92) in 293 enroled patients. Of these, 137/293 (47%) of patients [P a O2/FiO 2 76 (63–93)] were successfully weaned from HFNO. The median duration of HFNO was 6 (3–9) in those successfully treated versus 2 (1–5) days in those who failed ( p <0.001). A higher ratio of oxygen saturation/FiO2 to respiratory rate within 6 h (ROX-6 score) after HFNO commencement was associated with HFNO success (ROX-6; AHR 0.43, 0.31–0.60), as was use of steroids (AHR 0.35, 95%CI 0.19–0.64). A ROX-6 score of ≥3.7 was 80% predictive of successful weaning whilst ROX-6 ≤ 2.2 was 74% predictive of failure. In total, 139 patents (52%) survived to hospital discharge, whilst mortality amongst HFNO failures with outcomes was 129/140 (92%). Interpretation In a resource-constrained setting, HFNO for severe COVID-19 HRF is feasible and more almost half of those who receive it can be successfully weaned without the need for mechanical ventilation.

Transthoracic ultrasonography is still not utilized to its full potential by respiratory physicians, despite being a well-established and validated imaging modality. It allows for an immediate and mobile assessment that can potentially augment the physical examination of the chest. Ultrasound (US)-assisted procedures can be performed by a single clinician with no sedation and with minimal monitoring, even outside of theatre. The main indications for the use of transthoracic US are: the qualitative and quantitative description of pleu-ral effusions, pleural thickening, diaphragmatic dysfunction and chest-wall and pleural tumours. It may also be used to visualise lung tumours and other parenchymal pulmonary processes provided they abut the pleura. It is at least as sensitive as chest radiographs as far as the detection of a pneumothorax is concerned. It is the ideal tool to assist with thoracocentesis and drainage of effusions. The US-assisted fine-needle aspiration and/or cutting-needle biopsy of extrathoracic lymph nodes, lesions arising from the chest wall, pleura, peripheral lung and mediastinum, are safe and have a high yield in the hands of chest physicians. US may also guide the aspiration and biopsy of diffuse pulmonary infiltrates, consolidations and lung abscesses, provided the chest wall is abutted. Advanced applications of transthoracic US include the diagnosis of pulmonary embolism.

The most efficient and cost-effective approach to the diagnosis of pleural exudates remains controversial. Important considerations include the respective diagnostic yields of thoracocentesis, closed pleural biopsy and thoracoscopy; the incremental gain in diagnostic yield when sequentially combining these investigations; and the role of various image modalities. The diagnostic yield of thoracocentesis is in the order of 60% for malignancy and >90% for tuberculosis. A second aspiration may increase the yield for malignancy, but a third is generally superfluous. Many authorities consider thoracoscopy the investigation of choice in exudative pleural effusions where a thoracocentesis was nondiagnostic and particularly when malignancy is suspected. It allows for the direct inspection of the pleura and for talc poudrage. Thoracoscopy has a diagnostic yield of 91-95% for malignant disease and as high as 100% for pleural tuberculosis. Access to thoracoscopy is, however, limited in many parts of the world, as significant resources and expertise are required. Blind closed pleural biopsy has a yield of 80% for tuberculosis and <60% for pleural malignancy. Recent studies suggest that CT and/or ultrasound guidance may improve the yield, particularly for malignancy, where it may be as high as 88% and 83%, respectively. A second thoracocentesis combined with an image-assisted pleural biopsy with either an Abrams needle or cutting needle, depending on the setting, may therefore be an acceptable alternative to thoracoscopy. With such an approach, thoracoscopy may potentially be reserved for cases not diagnosed by means of closed pleural biopsy.

At least 40% of all patients with pneumonia will have an associated pleural effusion, although a minority will require an intervention for a complicated parapneumonic effusion or empyema. All patients require medical management with antibiotics. Empyema and large or loculated effusions need to be formally drained, as well as parapneumonic effusions with a pH <7.20, glucose <3.4 mmol/l (60 mg/dl) or positive microbial stain and/or culture. Drainage is most frequently achieved with tube thoracostomy. The use of fibrinolytics remains controversial, although evidence suggests a role for the early use in complicated, loculated parapneumonic effusions and empyema, particularly in poor surgical candidates and in centres with inadequate surgical facilities. Early thoracoscopy is an alternative to thrombolytics, although its role is even less well defined than fibrinolytics. Local expertise and availability are likely to dictate the initial choice between tube thoracostomy (with or without fibrinolytics) and thoracoscopy. Open surgical intervention is sometimes required to control pleural sepsis or to restore chest mechanics. This review gives an overview of parapneumonic effusion and empyema, focusing on recent developments and controversies.