Sleep Disturbance During Post-Traumatic Amnesia and Early Recovery After Traumatic Brain Injury.

After moderate to severe traumatic brain injury (TBI), sleep disturbance commonly emerges during the confused post-traumatic amnesia (PTA) recovery stage. However, the evaluation of early sleep disturbance during PTA, its recovery trajectory, and influencing factors is limited. This study aimed to evaluate sleep outcomes in patients experiencing PTA using ambulatory gold-standard polysomnography (PSG) overnight and salivary endogenous melatonin (a hormone that influences the sleep-wake cycle) assessment at two time-points. The relationships between PSG-derived sleep-wake parameters and PTA symptoms (i.e., agitation and cognitive disturbance) were also evaluated. In a patient subset, PSG was repeated after PTA had resolved to assess the trajectory of sleep disturbance. Participants with PTA were recruited from Epworth HealthCare's inpatient TBI Rehabilitation Unit. Trained nurses administered overnight PSG at the patient bedside using the Compumedics Somté portable PSG device (Compumedics, Ltd., Australia). Two weeks after PTA had resolved, PSG was repeated. On a separate evening, two saliva specimens were collected (at 24:00 and 06:00) for melatonin testing. Results of routine daily hospital measures (i.e., Agitated Behavior Scale and Westmead PTA Scale) were also collected. Twenty-nine patients were monitored with PSG (mean: 41.6 days post-TBI; standard deviation [SD]: 28.3). Patients' mean sleep duration was reduced (5.6 h, SD: 1.2), and was fragmented with frequent awakenings (mean: 27.7, SD: 15.0). Deep, slow-wave restorative sleep was reduced, or completely absent (37.9% of patients). The use of PSG did not appear to exacerbate patient agitation or cognitive disturbance. Mean melatonin levels at both time-points were commonly outside of normal reference ranges. After PTA resolved, patients (n = 11) displayed significantly longer mean sleep time (5.3 h [PTA]; 6.5 h [out of PTA], difference between means: 1.2, p = 0.005). However, disturbances to other sleep-wake parameters (e.g., increased awakenings, wake time, and sleep latency) persisted after PTA resolved. This is the first study to evaluate sleep disturbance in a cohort of patients as they progressed through the early TBI recovery phases. There is a clear need for tailored assessment of sleep disturbance during PTA, which currently does not form part of routine hospital assessment, to suggest new treatment paradigms, enhance patient recovery, and reduce its long-term impacts.

The Utility of a Virtual Emergency Medicine Elective for Visiting Medical Students.

Background Away rotations allow emergency medicine (EM)-bound fourth-year medical students to experience a residency program's educational culture and influence the ranking of residency programs. The financial cost and geographic distance have limited student participation in away electives. In recent years, COVID-19 pandemic-related restrictions on away rotations resulted in the creation of multiple virtual courses. Despite the lifting of restrictions, these courses may still have utility in helping students circumvent barriers to away rotations. Limitations of previously described courses include insufficient student-faculty interaction, which influences students' understanding of the educational environment. We sought to develop and evaluate a virtual EM elective for fourth-year medical students, focused on student-faculty interaction including precepted patient contact. Methodology We developed a two-week virtual EM elective for fourth-year medical students incorporating teaching sessions designed to optimize student-faculty interactions and attending-supervised telemedicine visits. After completion of the course, students completed an anonymous course evaluation. Results Course evaluations showed that the course improved students' understanding of our residency's educational environment by providing students with access to our residency program. The most frequently cited factors preventing participation in a traditional away elective were financial cost, limit in the allowed number of away rotations, and challenges in finding housing. Conclusions We believe this course may be an effective way of improving visiting students' understanding of the educational culture of our EM residency program. Thus, although pandemic-related restrictions have been lifted, this course may serve as a valuable adjunct to the traditional away EM rotation.

Expression of Concern: Direct observation of the THz Kerr effect (TKE) in deionized, distilled and buffered (PBS) water.

Expression of concern for 'Direct observation of the THz Kerr effect (TKE) in deionized, distilled and buffered (PBS) water' by Andrzej Dobek et al., Phys. Chem. Chem. Phys., 2017, 19, 26749-26757, https://doi.org/10.1039/c7cp04061j.

A comparison of agreement between actigraphy and polysomnography for assessing sleep during posttraumatic amnesia.

STUDY OBJECTIVES: Sleep disturbance often emerges in the early recovery phase following a moderate to severe traumatic brain injury, known as posttraumatic amnesia. Actigraphy is commonly employed to assess sleep, as it is assumed that patients in posttraumatic amnesia (who display confusion, restlessness, and agitation) would better tolerate this measure over gold-standard polysomnography (PSG). This study evaluated the agreement between PSG and actigraphy for determining (sleep/wake time, sleep efficiency, sleep latency, and awakenings) in patients experiencing posttraumatic amnesia. It also compared the epoch-by-epoch sensitivity, specificity, and accuracy between the Actigraph device's 4 wake threshold settings (low, medium, high, and automatic) to PSG. METHODS: The sample consisted of 24 inpatients recruited from a traumatic brain injury inpatient rehabilitation unit. Ambulatory PSG was recorded overnight at bedside and a Philips Actiwatch was secured to each patient's wrist for the same period. RESULTS: There were poor correlations between PSG and actigraphy for all parameters (Lin's concordance correlation coefficient = < 0.80). The low threshold displayed the highest correlation with PSG for wake and sleep time, albeit still low. Actigraphy displayed low specificity (ranging from 17.1% to 36.6%). There appears to be a greater disparity between actigraphy and PSG for patients with increased wake time. CONCLUSIONS: Actigraphy, while convenient, demonstrated poorer performance in determining sleep-wake parameters in patients with significantly disturbed sleep. Ambulatory PSG can provide a clearer understanding of the extent of sleep disturbances in these patients with reduced mobility during early rehabilitation. Study findings can help design future protocols of sleep assessment during posttraumatic amnesia and optimize treatment. CITATION: Fedele B, McKenzie D, Williams G, Giles R, Olver J. A comparison of agreement between actigraphy and polysomnography for assessing sleep during posttraumatic amnesia. J Clin Sleep Med. 2022;18(11):2605-2616.

Initial experience of a single referral centre using excimer laser coronary atherectomy-assisted expansion in undilatable stents: Excimer laser in undilatable stents.

Aims: Undilatable stents with severe peri-stent calcification are an important cause of target lesion failure and therapeutic options are limited. We report our initial experience with the safety and efficacy of excimer laser coronary atherectomy (ELCA)-assisted expansion of undilatable stents. Methods and results: ELCA was performed with saline, blood and contrast-enhanced trains. All lesions were post-dilated at high pressures and treated with a drug-eluting balloon. Thirty-one lesions with undilatable stents were included at a single centre with experienced operators from March 2016 to February 2021. The mean number of prior procedures for in-stent restenosis was three and 14 lesions had multiple layers of stent. Procedural success (>50% increase in minimal stent diameter [MSD]) and adequate stent expansion (MSD >70% of reference vessel diameter) was achieved in all lesions. At six-month follow-up (N=26 lesions), there were six periprocedural myocardial infarctions due to slow flow, two cardiac deaths and one target lesion revascularisation. There were no perforations. Conclusions: Our niche experience at a centre with experienced operators demonstrated that ELCA led to larger final lumen and stent dimensions in highly selected patients with undilatable stents and recurrent restenosis at the cost of relatively frequent slow flow.

Assessing Sleep Architecture With Polysomnography During Posttraumatic Amnesia After Traumatic Brain Injury: A Pilot Study.

BACKGROUND: Early-onset sleep disturbance is common following moderate to severe traumatic brain injury (TBI) and often emerges while patients are in posttraumatic amnesia (PTA). However, sleep disruptions during this subacute recovery phase are not well-defined, and research often utilizes indirect measures (actigraphy) that quantify sleep based on activity. This study aims to examine sleep macro-architecture and sleep quality directly with ambulatory polysomnography (PSG) and measure endogenous salivary melatonin levels for patients experiencing PTA following moderate to severe TBI. METHOD: Participants were recruited from an inpatient TBI rehabilitation unit. Nighttime PSG was administered at the patient's bedside. Two saliva specimens were collected for melatonin testing on a separate evening (24:00 and 06:00 hours) using melatonin hormone profile test kits. RESULTS: Of 27 patients in whom PSG was recorded, the minimum required monitoring time occurred in n =17 (adherence: 63%) at a median of 37.0 days (quartile 1 [Q1] to quartile 3 [Q3]: 21.5-50.5) postinjury. Median non-rapid eye movement (NREM) and REM sleep proportions were similar to normal estimates. Slow-wave sleep was reduced and absent in 35.3% of patients. Sleep periods appeared fragmented, and median sleep efficiency was reduced (63.4%; Q1-Q3: 55.1-69.2). Median melatonin levels at both timepoints were outside the normal range of values specified for this test (from Australian Clinical Labs). CONCLUSION: This study reports that ambulatory PSG and salivary melatonin assessment are feasible for patients experiencing PTA and offers new insight into the extent of sleep disturbance. Further research is necessary to understand associations between PTA and sleep disturbance.

Paediatric Horner Syndrome: How much further to investigate?

We report an infant with an early-onset Horner syndrome and normal urinary catecholamine levels. Further investigations with Nuclear medicine imaging with123I-MIBG (meta-iodo benzyl-guanidine) confirmed a right thoracic inlet mass consistent with a neuroblastoma, a tumor of neural crest origin. The authors emphasize the need for investigating idiopathic acquired pediatric Horner syndrome and the value of an MIBG scan as a diagnostic test for suspected neuroblastoma.

FDG PET-CT in pediatric Langerhans cell histiocytosis.

OBJECTIVE: Langerhans cell histiocytosis (LCH) in pediatric patients presents with single-system or multisystem disease. Accurate staging is essential for selecting the most appropriate therapy ranging from local surgery to chemotherapy. METHODS: A retrospective review was undertaken of reported fludeoxyglucose (FDG) positron emission tomography - computed tomography (PET-CT) scans performed in children with LCH from June 2006 to February 2017. Findings were compared with a reference standard of biopsy or informed clinical follow-up. RESULTS: One hundred nine scans were performed in 33 patients (age 7 weeks to 18 years). Nineteen patients had single-system, bone unifocal disease; seven patients had single-system, bone multifocal disease; four patients had single-system, skin unifocal disease; two patients had multisystem disease; and one patient had single-system, lymph node disease. Twenty-six scans were performed to stage biopsy-proven LCH, and 83 scans were performed during follow-up to assess treatment response or recurrence after therapy completion. At staging, FDG PET-CT detected all sites of biopsy-proven LCH (except where bone unifocal disease had been resected). There was one false-positive thymic finding that resolved without therapy. The per-patient false-positive rate of FDG PET-CT at staging was 4% (1/26). During follow-up, five LCH recurrences and one case of progressive disease on therapy occurred, all positive on FDG PET-CT. During follow-up two patients had FDG PET-CT scans with false-positive findings and one patient with a magnetic resonance imaging false-positive finding. The per-scan false-positive rate of FDG PET-CT during follow-up was 2% (2/83). CONCLUSIONS: FDG PET-CT is highly sensitive for the staging and follow-up of pediatric patients with LCH, and has a very low false-positive rate.

Terahertz endoscopic imaging for colorectal cancer detection: Current status and future perspectives.

Terahertz (THz) imaging is progressing as a robust platform for myriad applications in the field of security, health, and material science. The THz regime, which comprises wavelengths spanning from microns to millimeters, is non-ionizing and has very low photon energy: Making it inherently safe for biological imaging. Colorectal cancer is one of the most common causes of death in the world, while the conventional screening and standard of care yet relies exclusively on the physician's experience. Researchers have been working on the development of a flexible THz endoscope, as a potential tool to aid in colorectal cancer screening. This involves building a single-channel THz endoscope, and profiling the THz response from colorectal tissue, and demonstrating endogenous contrast levels between normal and diseased tissue when imaging in reflection modality. The current level of contrast provided by the prototype THz endoscopic system represents a significant step towards clinical endoscopic application of THz technology for in-vivo colorectal cancer screening. The aim of this paper is to provide a short review of the recent advances in THz endoscopic technology and cancer imaging. In particular, the potential of single-channel THz endoscopic imaging for colonic cancer screening will be highlighted.

Direct observation of the THz Kerr effect (TKE) in deionized, distilled and buffered (PBS) water.

Nonlinear THz pump-optical probe (THz-OKE) measurements in deionized, distilled and buffered (PBS) water are reported. A laser system that produces pulses at 800 nm, 30 fs FWHM, at a repetition rate of 1 kHz and an energy of 6 µJ per pulse, was a source of the probe optical beam and of the pump beam of THz 2 ps pulses. The electric field strength inducing birefringence in water samples was ETHz = 1.35 × 106 V m-1. These samples were chosen in order to study the effect of ionic concentration on water behavior in the ultrafast time scale. Differentiation between ultrafast effects resulting from internal H2O properties and those resulting from H2O-ion interactions was analyzed. These two effects may be connected to a difference in the fluctuations of the network of intermolecular hydrogen bonds of water molecules in the presence and absence of ions in solution. The results indicate that such fluctuations significantly alter water birefringence amplitude and its dynamics.

Lead Extraction for Treatment of Cardiac Device Infection: A 20-Year Single Centre Experience.

BACKGROUND: Infection is one of the most feared complications of cardiac implantable electronic devices. We report microbiology, antimicrobial therapy and infection recurrence in patients with cardiac device infection (CDI) treated with transvenous lead extraction (TLE) at a single centre over a 20-year period. METHODS: We identified a cohort of consecutive patients undergoing TLE for CDI by a single operator at a single high volume centre. Retrospective analysis of patient characteristics, microbiology, outcomes and infection recurrence was performed. RESULTS: Between May 1992 to March 2012, 348 patients underwent extraction due to localised or systemic infection. Seven hundred and twenty leads were extracted from these patients. The mean follow-up was 5.5+/-4.9 years. Staphylococcal species accounted for 81% of CDI. A difference is seen in infection onset for device revision compared with initial implants [median 10 months vs 24 months, P=0.0001]. Duration of antibiotics therapy depended on the nature of the CDI (21 days post TLE for systemic vs. 10 days for localised infection, P < 0.0001). There was comparable mortality in the 37 (11.2%) patients who did not have a replacement device compared with a replacement (30% vs 29%, P=0.9). Retained lead fragments are a risk factor for CDI recurrence (20.8% recurrence in retained fragments vs 4.3% in complete removal, P=0.006). CONCLUSION: Cardiac device infection can be successfully treated with a combination of TLE and antibiotic therapy. Device therapy can be safely withdrawn in some patients. Retained lead fragments are a risk factor for recurrent CDI following extraction.

Continuous-wave circular polarization terahertz imaging.

Biomedical applications of terahertz (THz) radiation are appealing because THz radiation is nonionizing and has the demonstrated ability to detect intrinsic contrasts between cancerous and normal tissue. A linear polarization-sensitive detection technique for tumor margin delineation has already been demonstrated; however, utilization of a circular polarization-sensitive detection technique has yet to be explored at THz frequencies. A reflective, continuous-wave THz imaging system capable of illuminating a target sample at 584 GHz with either linearly or circularly polarized radiation, and capable of collecting both cross- and copolarized signals remitted from the target, is implemented. To demonstrate the system's utility, a fresh ex vivo human skin tissue specimen containing nonmelanoma skin cancer was imaged. Both polarization-sensitive detection techniques showed contrast between tumor and normal skin tissue, although some differences in images were observed between the two techniques. Our results indicate that further investigation is required to explain the contrast mechanism, as well as to quantify the specificity and sensitivity of the circular polarization-sensitive detection technique.

Long-Term Outcomes Following Transvenous Lead Extraction.

BACKGROUND: Complications related to a cardiac implantable electronic device sometimes require transvenous lead extraction (TLE). We report long-term follow-up of patients undergoing TLE, particularly mortality, recurrent device infection, and need for repeat procedures. METHODS AND RESULTS: Consecutive patients undergoing TLE at a high-volume center were assessed for characteristics, indications, and outcomes. One thousand and six leads were extracted from 510 patients. Clinical success rate was 98.2% and complete procedural success was 92.2%, with one intraprocedural death. The mean follow-up was 5.5 +/- 4.9 years (range 0.2-18 years). Cumulative mortality was 3.3% at 30 days, 7.7% at 6 months, 10.0% at 1 year, and 33.0% at 10 years. Factors associated with increased long-term mortality included cardiac device infection (CDI; 33% vs 17% for non-CDI; χ² 13.8, P = 0.0003), procedural complications (43% vs 27% for no complications; χ² 4.2, P = 0.04), age (75.0 +/- 10.9 years in patients who died vs 62.7 +/- 17.2 years; P < 0.0001), and impaired renal function (creatinine 142.5 +/- 106.4 µmol/L in patients who died vs 106.3 +/- 90.7 µmol/L; P = 0.001). The rate of CDI after TLE was 3.9% (mean 11.6 months post extraction, range 0.3-84 months) and is higher in patients with retained lead fragments (13.5% vs 3.0% with complete removal; χ² 10.7, P = 0.001). CONCLUSION: Long-term mortality following TLE is high, particularly in those with systemic infection, procedural complications, advanced age, and renal impairment. Retained fragments are a risk factor for CDI post extraction.

Prognostic Significance of Peri-procedural Myocardial Infarction in the Era of High Sensitivity Troponin: A Validation of the Joint ACCF/AHA/ESC/WHF Universal Definition of Type 4a Myocardial Infarction with High Sensitivity Troponin T.

AIMS: This study aims to validate the joint ACCF/AHA/ESC/WHF Universal Definition of peri-procedural myocardial infarction (PMI) with high sensitivity troponin T (hsTnT). METHODS: A retrospective cohort study encompassing patients admitted to our institution between May 2012 and April 2013 was performed. RESULTS: 630 patients underwent percutaneous coronary interventions during the study period. Among them, 459 patients met the inclusion criteria and were eligible for analyses. 76.9% of these patients were male, while the mean age was 68.6. PMI was observed in 4.3% of the patients based on the Universal Definition. The predictors of PMI were chronic kidney disease (OR: 3.0, p=0.026), family history of cardiovascular disease (OR: 2.7, p=0.043) and use of IIb/IIIa inhibitors (OR 4.2, p=0.01). MACE was reported in 4.4% of the patients at 12 months, and was significantly and independently associated with PMI (OR 7.3, p=0.003) in a multivariate model which accounted for lesion complexity, patients' baseline clinical information, dual-antiplatelet status at follow-up and various procedural characteristics. The post-procedural hsTnT was much higher in those who suffered MACE than those who did not (156 v.s. 43 ng/L, p<0.001). CONCLUSION: PMI as defined by the current Universal Definition using hsTnT is an independent predictor of adverse clinical outcome at 12 months in patients undergoing PCI. Accordingly, PMI remains a clinically relevant factor in current practice and should be considered a key outcome measure in clinical trials and a potential target for therapy.

Imaging sentinel lymph nodes.

As the technique of sentinel lymph node (SLN) biopsy has evolved over the last 22 years, it has become increasingly evident that accurate SLN imaging is vital to allow surgical removal of only the true SLN(s) and not other nodes. Identifying the lymphatic collectors draining a tumor site and following them to the draining SLNs defines which nodes need to be removed for careful histologic examination. Current technology allows the exact location of each SLN to be defined. This allows the full benefits of SLN biopsy to be achieved, that is, highly accurate lymph node staging with minimal morbidity. In melanoma and breast cancer, the current practice of preoperative lymphoscintigraphy (LS) using peritumoral injections of tracer or injection adjacent to an excision biopsy site with dynamic imaging to visualize the lymphatic collectors and delayed imaging including single-photon emission computed tomography/computed tomography gives the best results. This information informs the surgical approach and allows rapid excision of the SLNs at surgery.In patients with visceral tumors where the primary cancer site is difficult to access, it appears that using fluorophores that are fluorescent under near-infrared light, injected during surgery, is evolving as the preferred technique.

Paradoxical cardiac and cerebral arterial gas embolus during percutaneous lead extraction in a patient with a patent foramen ovale.

A 42 year-old man presented for elective percutaneous lead extraction for pacemaker redundancy. The procedure was performed supine under general anaesthesia via the right femoral vein and was complicated by acute inferior ST elevation and hypotension. Urgent transoesophageal echocardiogram showed inferior left ventricular hypokinesis, right ventricular impairment, a patent foramen ovale and air in the left ventricle. Coronary angiography demonstrated normal coronary arteries, the ST changes resolved and the leads were subsequently removed intact. Post-operatively the patient displayed nystagmus, was managed with hyperbaric oxygen therapy, and had complete resolution of his symptoms. An MRI brain confirmed an acute left cerebellar infarction, and a diagnosis of paradoxical air embolus to the coronary and cerebral circulations was made. This case illustrates the risks associated with paradoxical embolism in patients with PFOs undertaking percutaneous lead extractions. It also highlights the need for further consideration into techniques to avoid this complication in all high-risk percutaneous procedures.

Voxel-based analysis of normal cerebral [18F]FDG uptake during childhood using statistical parametric mapping.

The changing pattern of relative cerebral (18)F-fluoro-2-deoxy-D-glucose (FDG) uptake that occurs during normal childhood development is not completely understood. Using SPM8 we undertook a voxel-based analysis of dedicated cerebral FDG scans in 28 children ranging in age from 11 months to 16 years to examine the effects of age on regional FDG uptake. The subjects included were children with suspected or proven extracranial malignancies without central nervous system metastases and no previous or current therapies or medical conditions likely to interfere with cerebral metabolism. The included cerebral FDG scans were considered to represent normal cerebral FDG distribution in a child of their age at the time of the scan. When normalised to whole brain mean uptake, the voxel-based analysis showed increasing FDG uptake with age in the premotor and prefrontal cortices, insula cortex, cingulate cortex, basal ganglia, thalamus, cerebellum and in small areas of the inferior temporal lobes and left Heschl's gyrus. These findings correlate with previous published analysis of the same data that used qualitative and maximal standardised uptake value (SUV(max)) analysis techniques. This data provides more regionally specific information and further supports the conclusion that relative cerebral FDG uptake in children has not reached a typical adult pattern by approximately one year of age but in fact changes throughout childhood. The results speak to the importance of using age-matched data or adjusting for age in the statistical analysis of studies comparing paediatric cerebral FDG scans to a control dataset to avoid bias due to different age distributions in the groups of subjects studied. The areas of increasing FDG uptake with age probably relate to underlying neuronal processes linked to normal neurodevelopment including key resting state networks.

Single-channel prototype terahertz endoscopic system.

We demonstrate the design and development of an innovative single-channel terahertz (THz) prototype endoscopic imaging system based on flexible metal-coated THz waveguides and a polarization specific detection technique. The continuous-wave (CW) THz imaging system utilizes a single channel to transmit and collect the reflected intrinsic THz signal from the sample. Since the prototype system relies on a flexible waveguide assembly that is small enough in diameter, it can be readily integrated with a conventional optical endoscope. This study aims to show the feasibility of waveguide enabled THz imaging. We image various objects in transmission and reflection modes. We also image normal and cancerous colonic tissues in reflectance mode using a polarization specific imaging technique. The resulting cross-polarized THz reflectance images showed contrast between normal and cancerous colonic tissues at 584 GHz. The level of contrast observed using endoscopic imaging correlates well with contrast levels observed in ex vivo THz reflectance studies of colon cancer. This indicates that the single-channel flexible waveguide-based THz endoscope presented here represents a significant step forward in clinical endoscopic application of THz technology to aid in in vivo cancer screening.