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Effect of initial switch-on within 24 hours of cochlear implantation using slim modiolar electrodes.

ABSTRACT: Reducing electrode impedance is an important factor in improving the functional benefits of cochlear implants (CIs). The immediate effect of early switch-on within 24 h of surgery on impedance among CI recipients with various types of electrodes has been reported previously; however, the immediate change and the evolution of electrode impedances of slim modiolar electrodes after early switch-on within 24 h of implantation has not. Therefore, the focus of this retrospective cohort study of CI patients was to compare the effect of early switch-on (n = 36) and conventional switch-on (n = 72) 2-4 weeks post-operation on impedance. Compared with impedance measured intraoperatively, our results demonstrate a significant decrease in impedance from 11.5 to 8.9 kΩ (p < 0.001) at 2-4 weeks after implantation in the early switch-on group, which sharply contrasted with elevated impedance values for conventional switch-on 2-4 weeks after implantation (from 10.7 to 14.2 kΩ, p = 0.001). Notably, a comparatively lower impedance than the conventional switch-on protocol was observed for up to 2 months post-operation. Most importantly, a much earlier stabilization of impedance can be achieved with the early switch-on protocol coupled with the slim modiolar electrode array compared to the conventional switch-on protocol, offering the advantage of reducing the number of required mapping sessions in the early stages of rehabilitation.

SUBMITTER: Sunwoo W

PROVIDER: S-EPMC8611070 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Cochlear implantation is a surgical procedure, which is performed on severely hearing-impaired patients. Impedance field telemetry is commonly used to determine the integrity of the cochlear implant device during and after surgery. At the Department of Otolaryngology, Cheng Hsin General Hospital (Taipei, Taiwan), the cochlear implant devices are switched on within 24 hours of their implantation. In the present study, the impedance changes of Advanced Bionics™ cochlear implant devices were compared with previous studies and other devices. The aim was to confirm previous hypotheses and to explore other potential associated factors that could influence impedance following cochlear implantation. The current study included 12 patients who underwent cochlear implantation at Cheng Hsin General Hospital with Advanced Bionics cochlear implant devices. The cochlear devices were all switched on within 24 hours of their implantation. The impedance was measured and compared across all contact channels of the electrode, both intra-operatively and post-operatively. The intra-operative impedance was compared with the switch-on impedance (within 24 hours of the cochlear implantation); the impedance was notably increased for all contact channels at switch-on. Of the 16 channels examined, 4 channels had a significant increase in impedance between the intra-operative measurement and the switch-on measurement. To the best of our knowledge, the impedance of a cochlear implant device can be affected by the diameter of the electrode, the position of the electrode arrays in the scala tympani, sheath formation and fibrosis surrounding the electrode after implantation and electrical stimulation during or after surgery. When the results of the current study were compared with previous studies, it was found that the impedance changes were opposite to that of Cochlear™ implant devices. This may be explained by the position of the electrode arrays, sheath formation, the blow-out effect and differences in electrical stimulation.

Project description:Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (? 2.5 cm) and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001). There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes with long-term hearing/speech performance.

Project description:BackgroundCardiac resynchronization therapy (CRT) response assessment relies on the QRS complex narrowing criterion. Yet one third of patients do not improve despite narrowed QRS after implantation. Electromechanical wave imaging (EWI) is a quantitative echocardiography-based technique capable of noninvasively mapping cardiac electromechanical activation in three dimensions. The aim of this exploratory study was to investigate the EWI technique, sensitive to ventricular dyssynchrony, for informing CRT response on the day of implantation.MethodsForty-four patients with heart failure with left bundle branch block or right ventricular (RV) paced rhythm and decreased left ventricular ejection fraction (LVEF; mean, 25.3 ± 9.6%) underwent EWI without and with CRT within 24 hours of device implantation. Of those, 16 were also scanned while in left ventricular (LV) pacing. Improvement in LVEF at 3-, 6-, or 9-month follow-up defined (1) super-responders (ΔLVEF ≥ 20%), (2) responders (10% ≤ ΔLVEF < 20%), and (3) nonresponders (ΔLVEF ≤ 5%). Three-dimensionally rendered electromechanical maps were obtained under RV, LV, and biventricular CRT pacing conditions. Mean RV free wall and LV lateral wall activation times were computed. The percentage of resynchronized myocardium was measured by quantifying the percentage of the left ventricle activated within 120 msec of QRS onset. Correlations between percentage of resynchronized myocardium and type of CRT response were assessed.ResultsLV lateral wall activation time was significantly different (P ≤ .05) among all three pacing conditions in the 16 patients: LV lateral wall activation time with CRT in biventricular pacing (73.1 ± 17.6 msec) was lower compared with LV pacing (89.5 ± 21.5 msec) and RV pacing (120.3 ± 17.8 msec). Retrospective analysis showed that the percentage of resynchronized myocardium with CRT was a reliable response predictor within 24 hours of implantation for significantly (P ≤ .05) identifying super-responders (n = 7; 97.7 ± 1.9%) from nonresponders (n = 17; 89.9 ± 9.9%).ConclusionElectromechanical activation mapping constitutes a valuable three-dimensional visualization tool within 24 hours of implantation and could potentially aid in the timely assessment of CRT response rates, including during implantation for adjustment of lead placement and pacing outcomes.

Project description:BackgroundSurgical stabilization of rib fractures (SSRF) should be performed early after injury. Factors that influence timing remain unknown. Our objective was to identify inherent variables that allow for early identification and treatment. We hypothesized that certain demographic, injury, and logistical factors are associated with SSRF <24 hours from admission.MethodsRetrospective review from an urban level 1 trauma center (10/2010-8/2019). Patients were grouped as SSRF <24 hours from admission vs. ≥24 hours. Demographics, transfer from an outside hospital (OSH), timing documentation, injury descriptors, surgeon on-call, and operative surgeon were collected. SSRF for chronic non-union was excluded.ResultsData from 173 patients were analyzed. Eighty-five patients (49%) were in the <24 hours group and 88 (51%) were in the ≥24 hours group. Baseline demographics were similar between groups. Injury severity was significantly higher in the late group: increased Injury Severity Score (ISS; 16.5 vs. 21.0, P<0.01), lower Glasgow Coma Scale (GCS; 15 vs. 14, P<0.01), more rib fractures (7 vs. 9, P=0.01), and increased incidence of face (6% vs. 16%, P=0.03), spine (22% vs. 47%, P<0.01), and pelvis fractures (8% vs. 25%, P<0.01). Patients admitted on a Wednesday were more likely to undergo early SSRF as compared to other days of the week (P=0.01) There was also a shorter time from the decision to perform SSRF to the actual operation in the early group, as compared to the late group (13 vs. 44 hours, P<0.01). Fifty (28.9%) SSRF cases were performed by the on-call surgeon; this percentage did not differ in the early vs. late group (33% vs. 25%, P=0.25). Patients needing pelvic fixation were more likely to be in the late group. Patients transferred from an OSH for SSRF were more likely to be in the early group (29% vs. 10%, P<0.01). Finally, likelihood of early surgery increased with increasing study year.ConclusionsApproximately one-half of SSRF cases were performed within 24 hours of admission. Factors that influence surgery within 24 hours of admission appear related to overall injury severity and systems issues, including day of admission, transfer from another facility, additional urgent pelvic surgery, and institutional experience with SSRF. Surgeon availability did not drive this disparity.

Project description:PurposeTo determine the initial success rate and its associated factors on cardiopulmonary resuscitation (CPR) in patients with cardiac arrest within 24 hours after receiving anesthesia for an emergency surgery.Patients and methodsAfter the hospital ethical committee gave approval for this study, the anesthesia providers recorded all relevant data regarding CPR in patients with cardiac arrest within 24 hours after anesthesia for emergency surgery at Maharaj Nakorn Chiang Mai Hospital, a university hospital in Northern Thailand. Only data from the cardiac arrest patients who received the first CPR attempt were included in the analysis. The end point of the initial success of CPR was return of spontaneous circulation (ROSC). Factors related to ROSC were determined by univariate analyses and multiple logistic regression analysis. The odds ratios (OR) and 95% confidence intervals (CI) were used to calculate the strength of the factors associated with the ROSC.ResultsOf the 96 cardiac arrest patients, 44 patients (45.8%) achieved ROSC. Factors associated with ROSC were electrocardiogram monitoring for detected cardiac arrest (OR =4.03; 95% CI =1.16-14.01; P=0.029), non-shock patients before arrest (OR =8.54; 95% CI =2.13-34.32; P=0.003), timing to response of activated CPR team within 1 minute (OR =9.37; 95% CI =2.55-34.39; P<0.001), having trained CPR teams (OR =8.76; 95% CI =2.50-30.72; P<0.001), and administration of more than one dose of epinephrine (OR =5.62; 95% CI =1.32-23.88; P<0.019).ConclusionPatients undergoing anesthesia for an emergency surgery are at risk for perioperative cardiac arrest with high mortality which requires immediate CPR. Our results have confirmed that early detection of cardiac arrest by vigilant electrocardiogram monitoring and prompt management with a qualified team are important factors in improving the success of CPR. Emergency surgical patients at risk for cardiac arrest should be promptly managed, with facilities available not only during the operation but also during the pre- to postoperative period.

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Effect of initial switch-on within 24 hours of cochlear implantation using slim modiolar electrodes.

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