The auditory midbrain implant: a new auditory prosthesis for neural deafness-concept and device description.

The auditory midbrain implant (AMI) is a new central auditory prosthesis designed for penetrating stimulation of the human inferior colliculus. The major group of candidates for the AMI consists of neurofibromatosis type 2 (NF2) patients who develop neural deafness because of growth and/or surgical removal of bilateral acoustic neuromas. Because of the absence of a viable auditory nerve, these patients cannot benefit from cochlear implants. An alternative solution has been the auditory brainstem implant (ABI), which stimulates the cochlear nucleus. However, speech perception performance in NF2 ABI patients has been limited. The fact that the ABI is able to produce high levels of speech perception in nontumor patients (with inaccessible cochleae or posttraumatic damage to the cochlear nerve) suggests that limitations in ABI performance in NF2 patients may be associated with cochlear nucleus damage caused by the tumors or the tumor removal process. Thus, stimulation of the auditory midbrain proximal to the damaged cochlear nucleus may be a better alternative for hearing restoration in NF2 patients. We propose the central nucleus of the inferior colliculus (ICC) as the potential site. A penetrating electrode array aligned along the well-defined tonotopic gradient of the ICC should selectively activate different frequency regions, which is an important elementfor supporting good speech understanding. The goal of this article is to present the ICC as an alternative site for an auditory implant for NF2 patients and to describe the design of the first human prototype AMI. Practical considerations for implementation of the AMI will also be discussed.     

Extrahepatic metabolism of sevoflurane in children undergoing orthotopic liver transplantation

BACKGROUND: Sevoflurane is metabolized by cytochrome P450 and produces inorganic fluoride. The anhepatic phase of liver transplantation provides a useful tool to study the extrahepatic metabolism of drugs. The authors therefore studied the extrahepatic metabolism of sevoflurane by measuring the fluoride production in children receiving sevoflurane solely during the anhepatic phase of orthotopic liver transplantation. METHODS: Children with end-stage liver disease undergoing orthotopic liver transplantation were studied. Anesthesia was provided with isoflurane, sufentanil, and pancuronium. In one group, isoflurane was replaced by sevoflurane as soon as the liver was removed from the patient and maintained until reperfusion of the new liver. Arterial blood samples were drawn at induction, before removal of the liver, 15 min and 30 min after the beginning of the anhepatic phase, at the unclamping of the new liver, and finally 60 and 120 min after the unclamping. Plasma fluoride concentrations were determined by ion-selective electrode. RESULTS: No differences between the two groups (n = 10) regarding age, weight, duration of the anhepatic phase, or basal level of inorganic fluoride were found. The fluoride concentration increased significantly as soon as sevoflurane was introduced; it remained stable in the group receiving isoflurane. The peak fluoride concentration was also significantly higher in the first group (mean +/- SD: 5.5 +/- 0.8 microM (sevoflurane group) versus 1.4 +/- 0.5 microM (isoflurane group) P < 0.05). CONCLUSIONS: These results demonstrate the existence of an extrahepatic metabolism of sevoflurane at least in children with end-stage liver disease.     

Positioning of a double-lumen endobronchial tube without the aid of any instruments: an implication for emergency management

BACKGROUND: Lung isolation and preservation of normal lung are the first lines of therapy in life-threatening massive hemoptysis. If bleeding continues but the side of origin is uncertain, use of a double-lumen tube (DLT) is reasonable. Utilizing a blind method to locate the bronchial cuff of a left-sided DLT without using any instrument, a DLT (Broncho-Cath, Mallinckrodt Medical Ltd., Athlone, Ireland) was successfully positioned without delay in a patient with massive hemoptysis, where auscultation could be misleading or useless and fiberoptic bronchoscope (FOB) was inapplicable. This study was performed to discern whether this blind method could substitute for FOB verification or auscultation in most circumstances where these two methods are unavailable or inapplicable. METHODS: After receiving informed consent and hospital ethics board approval, 58 elective thoracic surgical patients, aged 17 to 67 years, were enrolled in the study and divided into two groups. A conventional method using an FOB was used to locate the left-sided DLT in 29 patients (group 1). In the other 29 patients (group 2), the blind manual method was used. The left-sided DLT was inserted until some resistance was felt, at which time the bronchial cuff was inflated with approximately 2.0 mL of air. While gently holding the pilot with thumb and index finger of the nondominant hand, the DLT was slowly withdrawn until an abrupt decrease of pilot pressure was sensed. At that moment, the bronchial cuff was deflated, and the DLT was advanced approximately 1.5 cm; using an FOB, its position was checked by an independent observer not involved in positioning the DLT. Success was defined as the point when the proximal margin of the carina was within the margin of safety for the DLT, which is defined as the difference between the length of the left main bronchus and the length of the tube between the proximal margin of the left bronchial cuff and the left lumen tip. Postoperative FOB was performed to evaluate bronchial injury. RESULTS: In 26 of 29 patients (group 2), the position of the DLT was bronchoscopically confirmed to be a success. The other three cases were deemed to be too shallow; specifically, the bronchial cuffs were slightly herniated onto the carina (acceptable position). This method was more traumatic than FOB-guided DLT intubation (conventional method) (p = 0.001); however, the most severe damage was erosion. CONCLUSION: This method, which requires no specific instrument and no time-consuming technique, can be taught easily and may be used in a situation where the rapidity of lung isolation or collapse is the key to saving life. We conclude that this blind method can be an alternative to the FOB and/or auscultation for the positioning of DLT in an emergency situation.     

Factors associated with long-term smoking relapse in those who succeeded in smoking cessation using regional smoking cessation programs

It is known that approximately 10% of successful quitters relapse annually. This study aimed to investigate the factors related to long-term smoking relapse in individuals who succeeded in maintaining smoking cessation for 6 months after attending a regional smoking cessation program.This study enrolled 943 individuals registered for the regional smoking cessation program at the Busan Smoking Cessation Center in 2018–2019 who maintained smoking cessation for 6 months. A survey was conducted using a smartphone link or through phone calls, and the data for 305 participants who finally completed the survey were analyzed. The questionnaire addressed individual, inter-individual, organizational, and community-level factors related to smoking relapse. Multivariate logistic regression analysis was performed to evaluate the factors associated with smoking relapse by period. The Cox proportional hazard regression model was used for the factors associated with smoking relapse for the entire period.The smoking relapse rate at the time of the survey was 25.4%. In the analysis of smoking relapse by period, relapse was associated with the belief that smoking relieves stress, the number of single-person households, and poor subjective health status. In the analysis of smoking relapse during the entire period, we observed a significant association with the belief that smoking relieves stress (hazard ratio [HR]: 2.65, 95% confidence interval [CI]: 1.52–4.61), single-person households (HR: 1.95, 95% CI: 1.16–3.26), and high levels of emotional stress (HR: 1.72, 95% CI: 1.04–2.85).Long-term follow-up is necessary to prevent smoking relapse in single-person households, individuals who believe that smoking relieves stress, and those experiencing high levels of subjective emotional stress. Interventional therapies for stress relief and awareness improvement in smokers need to be developed.     

Malignant transformation of nevus sebaceous to basal-cell carcinoma: Case series,literature review,and management algorithm

Nevus sebaceous (NS) is a common congenital hamartoma of the skin composed predominantly of sebaceous glands. Although most NS are benign skin tumors, malignant transformations have been reported. There is still controversy about the lifetime risk of malignant degeneration and precise surgical criteria. This study reports cases of malignant degeneration and suggests a surgical treatment algorithm. The medical records of patients with basal-cell carcinoma (BCC) arising from NS between January 2001 and January 2021 were retrospectively reviewed. Patient demographics including lesion location, and tumor size were investigated. The symptoms, histological findings before and after excision, complications, and recurrence during 2-year follow-up periods were investigated. Ten patients were identified with BCC arising from NS lesions. All patients were female and the mean age was 52.11 years. All patients complained of sudden morphological changes, the most common type being rapid color changes. Two cases had histological findings that showed a miss-match between punch biopsy and excisional biopsy results. No recurrence was detected 2 years after surgeries in any patients. Cases after third stage, especially in over 40 years who report morphologic changes, should undergo total surgical excision as the first approach, with strong suspicion of malignant degeneration.     

Repurposing povidone-iodine to reduce the risk of SARS-CoV-2 infection and transmission: a narrative review

BackgroundAccumulating data suggest antiviral effects of povidone-iodine against the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. This narrative review aims to examine the antiviral mechanisms of povidone-iodine, efficacy of povidone-iodine against the SARS-CoV-2 virus, and safety of povidone-iodine to human epithelial cells and thyroid function.MethodsWe searched the electronic databases PubMed, Embase, Cochrane Library, ClinicalTrials.gov and World Health Organization’s International Clinical Trials Registry Platform for articles containing the keywords “povidone-iodine”, “SARS-CoV-2” and “COVID-19” from database inception till 3 June 2021.ResultsDespite in vitro data supporting the anti-SARS-CoV-2 effects of povidone-iodine, findings from clinical studies revealed differences in treatment response depending on study settings (healthy vs. hospitalized individuals), treatment target (nasal vs. oral vs. pharynx), method of administration (oral rinse vs. gargle vs. throat spray) and choice of samples used to measure study endpoints (nasopharyngeal vs. saliva). One large-scale clinical trial demonstrated reduction in the incidence of SARS-CoV-2 infection among participants who administered povidone-iodine 3 times daily during an active outbreak. Povidone-iodine is also used to disinfect the oro-pharyngeal space prior to dental or otolaryngology procedures. Although existing data suggest minimal impact of povidone-iodine on thyroid function, high-quality safety data are presently lacking.ConclusionsPovidone-iodine application to the oropharyngeal space could complement existing non-pharmacological interventions to reduce SARS-CoV-2 infection especially in high exposure settings.

Key messages

• Accumulating data suggest antiviral effects of povidone-iodine against the SARS-CoV-2 virus.
• Findings from clinical studies reveal differences in treatment response depending on study settings, treatment target, method of administration and choice of samples used to measure study endpoints. One large-scale clinical trial observed reduction in the incidence of SARS-CoV-2 infection among participants who administered povidone-iodine 3 times daily during an active outbreak.
• Povidone-iodine application to the oropharyngeal space could complement existing non-pharmacological interventions to reduce SARS-CoV-2 infection especially in high exposure settings.