Use of temporary tracheostomy occlusion to reduce the risk of sternal wound infection after sternotomy in congenital cardiac surgery.

OBJECTIVE: To describe a method of reducing the risk of sternal wound infection after sternotomy in children with a pre-existing tracheostomy. To report our outcomes using this method from 1 January, 2013 to 31 August, 2023. METHODS: We describe a method for temporarily occluding the tracheal stoma with a removable implant with the primary goal of reducing the risk of sternotomy wound infection by preventing soilage due to tracheostomal secretions. We then performed a retrospective review of all children who underwent temporary tracheostomal occlusion between 1 January, 2013 and 31 August, 2023 at our quaternary care children's hospital. Clinical variables were extracted from the hospital medical records. The rates of antibiotic use and minor and major complications during the period when the stoma plug was in place were recorded. RESULTS: Totally, 19 patients underwent tracheal stoma plugging prior to sternotomy and were included in our analysis. There were two cases of sternal wound infection; one case occurred while the stoma plug was in place, and one developed four days following plug removal. There was one minor complication, with one patient requiring stoma revision via serial dilation at bedside at the time of recannulation. There were no deaths. CONCLUSION: Temporary occlusion of the tracheal stoma with an impermeable plug is a viable option for reducing the risk of sternal wound infection in children with a pre-existing tracheostomy who are undergoing sternotomy.

Thermal Excitation of the Mechanotransduction Apparatus of Hair Cells.

Although a hair bundle is normally deflected by mechanical stimuli, we found that irradiation of a hair cell from the bullfrog's sacculus with ultraviolet light causes rapid motion of the hair bundle toward its tall edge. This movement is associated with opening of mechanotransduction channels and disappears when tip links are disrupted. We localized the absorptive element responsible for the motion to the region directly below the hair bundle and measured an action spectrum similar to the absorption spectra of mitochondrial constituents. Temperature measurements revealed heating around the site of absorption; direct heating of the hair bundle confirmed that the response to light is mediated through heat. Although mechanical offsets of the hair bundle revealed that heat softens gating springs, it also acts directly to open transduction channels. This study identifies an unconventional method of hair-cell stimulation and clarifies the previously unexplained sensitivity of auditory organs to thermal stimulation.

Physiological Preparation of Hair Cells from the Sacculus of the American Bullfrog (Rana catesbeiana).

The study of hearing and balance rests upon insights drawn from biophysical studies of model systems. One such model, the sacculus of the American bullfrog, has become a mainstay of auditory and vestibular research. Studies of this organ have revealed how sensory cells hair can actively detect signals from the environment. Because of these studies, we now better understand the mechanical gating and localization of a hair cell's transduction channels, calcium's role in mechanical adaptation, and the identity of hair cell currents. This highly accessible organ continues to provide insight into the workings of hair cells. Here we describe the preparation of the bullfrog's sacculus for biophysical studies on its hair cells. We include the complete dissection procedure and provide specific protocols for the preparation of the sacculus in specific contexts. We additionally include representative results using this preparation, including the calculation of a hair bundle's instantaneous force-displacement relation and measurement of a bundle's spontaneous oscillation.