Comparison between ultrasound and chest X-ray to confirm central venous catheter tip position.

Background: Mechanical central venous catheter (CVC) placement complications are mostly malposition or iatrogenic pneumothorax. Verification of catheter position by chest X-ray (CXR) is usually performed postoperatively. Objectives: This prospective observational study assessed the diagnostic accuracy of peri-operative ultrasound and a 'bubble test' to detect malposition and pneumothorax. Method: Sixty-one patients undergoing peri-operative CVC placement were included. An ultrasound protocol was used to directly visualise the CVC, perform the 'bubble test' and assess for the presence of pneumothorax. The time from agitated saline injection to visualisation of microbubbles in the right atrium was evaluated to determine the correct position of the CVC. The time required to perform the ultrasound assessment was compared to that of conducting the CXR. Results: Chest X-ray identified 12 (19.7%) malpositions while ultrasound identified 8 (13.1%). Ultrasound showed a sensitivity of 0.85 (95% confidence interval [CI]: 0.72 to 0.93) and a specificity of 0.5 (95% CI: 0.16 to 0.84). The positive and negative predictive values were 0.92 (95% CI: 0.80 to 0.98) and 0.33 (95% CI: 0.10 to 0.65), respectively. No pneumothorax was identified on ultrasound and CXR. The median time for ultrasound assessment was significantly shorter at 4 min (interquartile range [IQR]: 3-6 min), compared to performing a CXR that required a median time of 29 min (IQR: 18-56 min) (p < 0.0001). Conclusion: This study showed that ultrasound produced a high sensitivity and moderate specificity in detecting CVC malposition. Contribution: Ultrasound can improve efficiency when used as a rapid bedside screening test to detect CVC malposition.

Radiology blues: Comparing occupational blue-light exposure to recommended safety standards.

Background: The blue-light hazard is a well-documented entity addressing the detrimental health effects of high-energy visible light photons in the range of 305 nm - 450 nm. Radiologists spend long hours in front of multiple light-emitting diode (LED)-based diagnostic monitors emitting blue light, predisposing them to potentially higher blue-light dosages than other health professionals. Objectives: The authors aimed to quantify the blue light that radiology registrars are exposed to in daily viewing of diagnostic monitors and compared this with international occupational safety standards. Method: A limited cross-sectional observational study was conducted. Four radiology registrars at two academic hospitals in Bloemfontein from 01 October 2021 to 30 November 2021 participated. Diagnostic monitor viewing times on a standard workday were determined. Different image modalities obtained from 01 June 2019 to 30 November 2019 were assessed, and blue-light radiance was determined using a spectroscope and image analysis software. Blue-light radiance values were compared with international safety standards. Results: Radiology registrars spent on average 380 min in front of a diagnostic display unit daily. Blue-light radiance from diagnostic monitors was elevated in higher-intensity images such as chest radiographs and lower for darker images like MRI brain studies. The total blue-light radiance from diagnostic display units was more than 10 000 times below the recommended threshold value for blue-light exposure. Conclusion: Blue-light radiance from diagnostic displays measured well below the recommended values for occupational safety. Hence, blue-light exposure from diagnostic monitors does not significantly add to the occupational health burden of radiologists. Contribution: Despite spending long hours in front of diagnostic monitors, radiologists' exposure to effective blue-light radiance from monitors was far below hazardous values. This suggests that blue-light exposure from diagnostic monitors does not increase the occupational health burden of radiologists.