Point-of-care Ultrasound-guided Central Venous Catheter Confirmation in Ultrasound Nonexperts.

OBJECTIVE: Emerging evidence suggests that chest radiography (CXR) following central venous catheter (CVC) placement is unnecessary when point-of-care ultrasound (POCUS) is used to confirm catheter position and exclude pneumothorax. However, few providers have adopted this practice, and it is unknown what contributing factors may play a role in this lack of adoption, such as ultrasound experience. The objective of this study was to evaluate the diagnostic accuracy of POCUS to confirm CVC position and exclude a pneumothorax after brief education and training of nonexperts. METHODS: We performed a prospective cohort study in a single academic medical center to determine the diagnostic characteristics of a POCUS-guided CVC confirmation protocol after brief training performed by POCUS nonexperts. POCUS nonexperts (emergency medicine senior residents and critical care fellows) independently performed a POCUS-guided CVC confirmation protocol after a 30-minute didactic training. The primary outcome was the diagnostic accuracy of the POCUS-guided CVC confirmation protocol for malposition and pneumothorax detection. Secondary outcomes were efficiency and feasibility of adequate image acquisition, adjudicated by POCUS experts. RESULTS: Twenty-six POCUS nonexperts collected data on 190 patients in the final analysis. There were five (2.5%) CVC malpositions and six (3%) pneumothoraxes on CXR. The positive likelihood ratios of POCUS for malposition detection and pneumothorax were 12.33 (95% confidence interval [CI] = 3.26 to 46.69) and 3.41 (95% CI = 0.51 to 22.76), respectively. The accuracy of POCUS for pneumothorax detection compared to CXR was 0.93 (95% CI = 0.88 to 0.96) and the sensitivity was 0.17 (95% CI = 0.00 to 0.64). The median (interquartile range) time for CVC confirmation was lower for POCUS (9 minutes [8.5-9.5 minutes]) compared to CXR (29 minutes [1-269 minutes]; Mann-Whitney U, p < 0.01). Adequate protocol image acquisition was achieved in 76% of the patients. CONCLUSION: Thirty-minute training of POCUS in nonexperts demonstrates adequate diagnostic accuracy, efficiency, and feasibility of POCUS-guided CVC position confirmation, but not exclusion of pneumothorax.

Challenges and opportunities of pH in chronic wounds.

Regarded as a silent epidemic, chronic wounds are a global public health issue. Wound healing is a complex, synchronized cascade of physiological processes restoring the anatomic and functional integrity of the skin; however, chronic wounds fail to proceed through the wound healing cascade. Wound pH oscillates during wound healing, usually traversing from a neutral pH to an acidic pH, while chronic wounds perpetuate in an elevated alkaline milieu. Although a neglected clinical parameter, pH has implications for relatively all pathologies of wound healing affecting oxygen release, angiogenesis, protease activity, bacterial toxicity and antimicrobial activity. Despite the array of wound healing products currently marketed, understanding the implications of pH on arresting wound healing can stimulate innovation within this vast market.

Development of an Infection-Responsive Fluorescent Sensor for the Early Detection of Urinary Catheter Blockage.

Formation of crystalline biofilms following infection by Proteus mirabilis can lead to encrustation and blockage of long-term indwelling catheters, with serious clinical consequences. We describe a simple sensor, placed within the catheter drainage bag, to alert of impending blockage via a urinary color change. The pH-responsive sensor is a dual-layered polymeric "lozenge", able to release the self-quenching dye 5(6)-carboxyfluorescein in response to the alkaline urine generated by the expression of bacterial urease. Sensor performance was evaluated within a laboratory model of the catheterized urinary tract, infected with both urease positive and negative bacterial strains under conditions of established infection, achieving an average "early warning" of catheter blockage of 14.5 h. Signaling only occurred following infection with urease positive bacteria. Translation of these sensors into a clinical environment would allow appropriate intervention before the occurrence of catheter blockage, a problem for which there is currently no effective control method.