An Australian COVID-19 respiratory care unit experience.

BACKGROUND: Coronavirus disease (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with a heterogeneous presentation ranging from severe pneumonitis to asymptomatic infection. International studies have demonstrated the utility of respiratory care units (RCUs) to facilitate the delivery of non-invasive ventilation techniques to patients with COVID-19 pneumonitis. AIMS: This study aims to describe the patient characteristics, flow and outcomes of admissions to the Royal Melbourne Hospital (RMH) COVID-19 RCU (CRCU) during its initial period of operation. METHODS: Single-centre retrospective cohort study, all patients admitted to CRCU between 17 September and 10 December 2021 were included in this study. Patient demographics, including comorbidities and limitations of medical treatment, were analysed. Admission source and discharge destination were reviewed. Length of stay was recorded. Finally, in-hospital and CRCU mortality were analysed. RESULTS: Ninety-seven patients, comprising 111 admissions, occurred during the study period with median age of 65 years (48% female). Most patients were admitted from and discharged to the ward. Twenty patients died in hospital (21%), with age, 4C score, comorbidity and presence of obstructive lung disease predicting mortality (area under the curve (AUC) 0.85, P < 0.001). Mortality was significantly higher in those over 65 years of age compared to those under 65 (P < 0.001), or those deemed not for intubation compared to those for intubation (P = 0.0019). CONCLUSIONS: This study demonstrates the feasibility of operating a CRCU within an Australian tertiary healthcare setting.

Teaching Radial Endobronchial Ultrasound with a Three-Dimensional-printed Radial Ultrasound Model.

BACKGROUND: Peripheral pulmonary lesion (PPL) incidence is rising because of increased chest imaging sensitivity and frequency. For PPLs suspicious for lung cancer, current clinical guidelines recommend tissue diagnosis. Radial endobronchial ultrasound (R-EBUS) is a bronchoscopic technique used for this purpose. It has been observed that diagnostic yield is impacted by the ability to accurately manipulate the radial probe. However, such skills can be acquired, in part, from simulation training. Three-dimensional (3D) printing has been used to produce training simulators for standard bronchoscopy but has not been specifically used to develop similar tools for R-EBUS. OBJECTIVE: We report the development of a novel ultrasound-compatible, anatomically accurate 3D-printed R-EBUS simulator and evaluation of its utility as a training tool. METHODS: Computed tomography images were used to develop 3D-printed airway models with ultrasound-compatible PPLs of "low" and "high" technical difficulty. Twenty-one participants were allocated to two groups matched for prior R-EBUS experience. The intervention group received 15 minutes to pretrain R-EBUS using a 3D-printed model, whereas the nonintervention group did not. Both groups then performed R-EBUS on 3D-printed models and were evaluated using a specifically developed assessment tool. RESULTS: For the "low-difficulty" model, the intervention group achieved a higher score (21.5 ± 2.02) than the nonintervention group (17.1 ± 5.7), reflecting 26% improvement in performance (P = 0.03). For the "high-difficulty" model, the intervention group scored 20.2 ± 4.21 versus 13.3 ± 7.36, corresponding to 52% improvement in performance (P = 0.02). Participants derived benefit from pretraining with the 3D-printed model, regardless of prior experience level. CONCLUSION: 3D-printing can be used to develop simulators for R-EBUS education. Training using these models significantly improves procedural performance and is effective in both novice and experienced trainees.

Reduction of COPD Hyperinflation by Endobronchial Valves Improves Intercostal Muscle Morphology on Ultrasound.

Background and Objectives: Parasternal intercostal ultrasound morphology reflects spirometric COPD severity. Whether this relates to the systemic nature of COPD or occurs in response to hyperinflation is unknown. We aimed to assess changes in ultrasound parasternal intercostal muscle quantity and quality (echogenicity) in response to relief of hyperinflation. We hypothesised that reduction in hyperinflation following endobronchial valve (EBV) insertion would increase ultrasound parasternal thickness and decrease echogenicity. Methods: In this prospective cohort study, eight patients with severe COPD underwent evaluation of health-related quality of life, lung function, and sonographic thickness of 2nd parasternal intercostal muscles and diaphragm thickness, both before and after EBV insertion. Relationships between physiological and radiographic lung volumes, quality of life and ultrasound parameters were determined. Results: Baseline FEV1 was 1.02L (SD 0.37) and residual volume (RV) was 202% predicted (SD 41%). Median SGRQ was 63.26 (range 20-70.6). Change in RV (-0.51 ± 0.9L) following EBV-insertion showed a strong negative correlation with change in parasternal thickness (r = -0.883) ipsilateral to EBV insertion, as did change in target lobe volume (-0.89 ± 0.6L) (r = -0.771). Parasternal muscle echogenicity, diaphragm thickness and diaphragm excursion did not significantly change. Conclusions: Dynamic changes in intercostal muscle thickness on ultrasound measurement occur in response to relief of hyperinflation. We demonstrate linear relationships between intercostal thickness and change in hyperinflation following endobronchial valve insertion. This demonstrates the deleterious effect of hyperinflation on intrinsic inspiratory muscles and provides an additional mechanism for symptomatic response to EBVs.

Parasternal intercostal muscle ultrasound in chronic obstructive pulmonary disease correlates with spirometric severity.

In chronic obstructive pulmonary disease (COPD), loss of computed tomography (CT)-measured intercostal mass correlates with spirometric severity. Intercostal muscle ultrasound offers a repeatable and radiation-free alternative, however requires validation. We aimed to determine the reliability of parasternal intercostal muscle ultrasound, and the concurrent validity of parasternal ultrasound with clinicometric parameters. Twenty stable COPD patients underwent ultrasound measurement of thickness and echogenicity of 2nd and 3rd parasternal intercostal muscles, dominant pectoralis major and quadriceps, and diaphragm thickness; spirometry; and chest CT. Intra-rater intraclass correlation (ICC) for ultrasound intercostal thickness was 0.87-0.97 depending on site, with echogenicity ICC 0.63-0.91. Inter-rater ICC was fair to excellent. Ultrasound intercostal thickness moderately correlated with FEV1% predicted (r = 0.33) and quadriceps thickness (r = 0.31). Echogenicity correlated negatively with FEV1% predicted (r = -0.32). CT-measured lateral intercostal mass correlate negatively with parasternal ultrasound intercostal thickness. These data confirm ultrasound of parasternal intercostal musculature is reproducible. Lower intercostal muscle quantity and quality reflects greater COPD spirometric severity. This novel tool may have biomarker potential for both the systemic effects of COPD on muscle as well as local disruption of respiratory mechanics. The negative correlation between CT and ultrasound measurements may reflect complex site-dependent interactions between respiratory muscles and the chest wall.

Accuracy of Patient Perception of Supine Sleep.

STUDY OBJECTIVES: For clinicians involved in investigating and treating sleep disorders, understanding the accuracy of patient recall of supine sleep would allow informed comparisons between polysomnography (PSG) and patient-reported sleep in patients with supine-predominant obstructive sleep apnea. This study aims to assess the accuracy of patient perception of supine sleep. METHODS: Prospective observational cohort study, assessing patient perception of total sleep and supine sleep, including duration. Data were analyzed utilizing descriptive statistics, bias-plot (Bland-Altman) analysis, and Spearman correlation (rs) to analyze relationships among continuous data. RESULTS: Total number of patients who underwent PSG was 518, with data from 368 of these patients analyzed. Most of these patients underwent diagnostic PSG (49.2%). Patients were excluded because of missing or incomplete data (n = 133) or immobility (n = 17). Some patients (n = 97, 26%) did not perceive supine sleep, with 34 (35% of those with unperceived supine sleep or 9% of whole group) of these having more than 60 minutes of PSG supine sleep (range 0-305.5 minutes). All "unsure" patients (n = 8, 2.2%) had significant supine sleep recorded (31.5-257.5 minutes). For the presence of any PSG supine sleep, questioning had a sensitivity of 77.9%, specificity 72.7% with positive predictive value of 96.7% and negative predictive value of 24.5%. There was a significant correlation (rs = 0.63, P < .0001) between perceived and PSG supine sleep, but wide limits of agreement (-246.9 to 194.2 minutes). CONCLUSIONS: In patients undergoing in-laboratory PSG, the perception of supine sleep predicts the presence of PSG supine sleep. However, questioning patients has a poor negative predictive value and patient estimates of supine sleep duration are inaccurate.

Diagnostic chest ultrasound for acute respiratory failure.

Acute respiratory failure (ARF) is a common life-threatening medical condition, with multiple underlying aetiologies. Diagnostic chest ultrasound provides accurate diagnosis of conditions that commonly cause ARF, and may improve overall diagnostic accuracy in critical care settings as compared to standard diagnostic approaches. Respiratory physicians are becoming increasingly familiar with ultrasound as a part of routine clinical practice, although the majority of data to date has focused on the emergency and intensive care settings. This review will examine the evidence for the use of diagnostic chest ultrasound, focusing on different levels of imaging efficacy; specifically ultrasound test attributes, impacts on clinician behaviour and impact on health outcomes. The evidence behind use of multi-modality ultrasound examinations in ARF will be reviewed. It is hoped that readers will become familiar with the advantages and potential issues with chest ultrasound, as well as evidence gaps in the field.

A prospective cohort study of thoracic ultrasound in acute respiratory failure: the C3PO protocol.

OBJECTIVES: This study was performed to assess the clinical utility of a standardised thoracic ultrasound examination when added to standard care in patients with acute respiratory failure admitted to an intermediate care unit. This study aimed to assess the impact on clinical diagnosis, clinician confidence and management. Ultrasound has been shown to have utility in patients admitted to intensive care and emergency; however, utility in a ward setting is unknown. DESIGN: Prospective cohort study. SETTING: Tertiary hospital in Melbourne, Australia. PARTICIPANTS: 50 patients with acute respiratory failure requiring admission to an intermediate care unit. MAIN OUTCOME MEASURES: (1) Change in clinical diagnosis or additional clinical diagnosis following thoracic ultrasound. (2) Change in diagnostic confidence following thoracic ultrasound. (3) Change to management following thoracic ultrasound. RESULTS: In 34% of patients, ultrasound detected unexpected findings that changed or added to the clinical diagnosis. Diagnostic confidence was increased in 44%, and the treating clinician altered the management plan in 30% as a result of the ultrasound. Ultrasound was particularly useful in clarifying the diagnosis in patients with multiple initial diagnoses, reducing to a single diagnosis in 69%. CONCLUSIONS: Thoracic ultrasound has clinical utility in non-intubated adults with acute respiratory failure managed outside intensive care settings. It changed aetiological diagnosis, increases diagnostic confidence and altered clinical management in one out of three patients scanned. Our results suggest extended utility of thoracic ultrasound in acute respiratory failure to a broader context outside the intensive care unit population.

Accuracy and safety of ward based pleural ultrasound in the Australian healthcare system.

BACKGROUND AND OBJECTIVE: Ultrasound has been shown to improve the accuracy and safety of pleural procedures. Studies to date have been performed in large, specialized units, where pleural procedures are performed by a small number of highly specialized physicians. There are no studies examining the safety and accuracy of ultrasound in the Australian healthcare system where procedures are performed by junior doctors with a high staff turnover. METHODS: We performed a retrospective review of the ultrasound database in the Respiratory Department at the Royal Melbourne Hospital to determine accuracy and complications associated pleural procedures. RESULTS: A total of 357 ultrasounds were performed between October 2010 and June 2013. Accuracy of pleural procedures was 350 of 356 (98.3%). Aspiration of pleural fluid was successful in 121 of 126 (96%) of patients. Two (0.9%) patients required chest tube insertion for management of pneumothorax. There were no recorded pleural infections, haemorrhage or viscera puncture. CONCLUSION: Ward-based ultrasound for pleural procedures is safe and accurate when performed by appropriately trained and supported junior medical officers. Our findings support this model of pleural service care in the Australian healthcare system.

Electromagnetic Navigation Bronchoscopy-directed Pleural Tattoo to Aid Surgical Resection of Peripheral Pulmonary Lesions.

BACKGROUND: Limited (wedge) resection of pulmonary lesions is frequently performed as a diagnostic/therapeutic procedure. Some lesions may be difficult to locate thoracoscopically with conversion to open thoracotomy or incomplete resection being potential limitations to this approach. Multiple methods have been described to aid video-assisted thoracoscopic surgical (VATS) wedge resection of pulmonary nodules, including hookwire localization, percutaneous tattoo, or intraoperative ultrasound. We report on our experience using electromagnetic navigation bronchoscopic dye marking of small subpleural lesions to aid VATS wedge resection. METHODS: A retrospective cohort study of consecutive patients undergoing VATS wedge resection of peripheral lesions. Preoperative bronchoscopy with electromagnetic navigation was utilized to guide a 25 G needle to within/adjacent to the target lesion with injection of 1 mL of methylene blue or indigo carmine under fluoroscopic vision. RESULTS: Six patients underwent bronchoscopic marking of peripheral pulmonary lesions, navigation deemed successful in all patients, with no procedural complications. Surgery was performed within 24 hours of bronchoscopic marking. Pleural staining by dye was visible thoracoscopically in all 6 lesions either adjacent to or overlying the lesion. All lesions were fully excised with wedge resection. Pathologic examination confirmed accuracy of dye staining. CONCLUSIONS: Electromagnetic navigation bronchoscopic dye marking of peripheral lesions is feasible, without complications commonly associated with percutaneous marking procedures. Further experience is required but early findings suggest that this method may have utility in aiding minimally invasive resection of small subpleural lesions.

Utility of EBUS-TBNA for diagnosis of mediastinal tuberculous lymphadenitis: a multicentre Australian experience.

BACKGROUND: Endobronchial ultrasound (EBUS) transbronchial needle aspiration (TBNA) is an important diagnostic procedure for the interrogation of mediastinal lymph nodes. There is limited data describing the accuracy & safety of this technique for the diagnosis of tuberculous mediastinal lymphadenitis. METHODS: A multi-centre retrospective study of all EBUS-guided TBNA procedures that referred samples for mycobacteriology was performed. Results were correlated with post-procedural diagnoses after a period of surveillance and cross-checked against relevant statewide tuberculosis (TB) registries, and sensitivity and specificity was calculated. In addition, nucleic acid amplification techniques (NAAT) were assessed, and sensitivity and specificity calculated using positive mycobacterial culture as the reference gold standard. RESULTS: One hundred and fifty-nine patients underwent EBUS-TBNA and had tissue referred for mycobacterial culture, of which 158 were included in the final analysis. Thirty-nine were ultimately diagnosed with TB (25%). Sensitivity of EBUS-TBNA for microbiologically confirmed tuberculous mediastinal lymphadenitis was 62% (24/39 cases). Specificity was 100%. Negative predictive value (NPV) and diagnostic accuracy for microbiologic diagnosis was 89% [95% confidence intervals (CI), 82-93%] and 91% (95% CI, 84-94%) respectively. For a composite clinicopathologic diagnosis of TB NPV and accuracy were 98% (95% CI, 93-99%) and 98% (95% CI, 95-99%) respectively. Sensitivity for NAAT was 38% (95% CI, 18-65%). CONCLUSIONS: EBUS-TBNA is a safe and well tolerated procedure in the assessment of patients with suspected isolated mediastinal lymphadenitis and demonstrates good sensitivity for a microbiologic diagnosis of isolated mediastinal lymphadenitis. When culture and histological results are combined with high clinical suspicion, EBUS-TBNA demonstrates excellent diagnostic accuracy and NPV for the diagnosis of mediastinal TB lymphadenitis. We suggest EBUS-TBNA should be considered the procedure of choice for patients in whom TB is suspected.