BACKGROUND Ventricular fibrillation (VF) is characterized by multiple wavelets and rotors. No equation to predict the number of rotors and wavelets observed during fibrillation has been validated in human VF. OBJECTIVE The purpose of this study was to test the hypothesis that a single equation derived from a Markov M/M/8 birth-death process could predict the number of rotors and wavelets occurring in human clinical VF. METHODS Epicardial induced VF (256-electrode) recordings obtained from patients undergoing cardiac surgery were studied (12 patients; 62 epochs). Rate constants for phase singularity (PS) (which occur at the pivot points of rotors) and wavefront (WF) formation and destruction were derived by fitting distributions to PS and WF interformation and lifetimes. These rate constants were combined in an M/M/8 governing equation to predict the number of PS and WF in VF episodes. Observed distributions were compared to those predicted by the M/M/8 equation. RESULTS The M/M/8 equation accurately predicted average PS and WF number and population distribution, demonstrated in all epochs. Self-terminating episodes of VF were distinguished from VF episodes requiring termination by a trend toward slower PS destruction, slower rates of PS formation, and a slower mixing rate of the VF process, indicated by larger values of the second largest eigenvalue modulus of the M/M/8 birth-death matrix. The longest-lasting PS (associated with rotors) had shorter interactivation time intervals compared to shorter-lasting PS lasting <150 ms (similar to 1 PS rotation in human VF). CONCLUSION The M/M/8 equation explains the number of wavelets and rotors observed, supporting a paradigm of VF based on statistical fibrillatory dynamics.

The mechanisms sustaining ventricular fibrillation (VF) remain unclear. At present VF is commonly characterised by two mechanisms, multi-wavelet re-entry and rotors, but no governing equation exists to explain and predict their population dynamics.

VF is commonly characterised by two mechanisms, multi wavelet reentry and rotors, but no governing equation exists to explain and predict their population dynamics. We hypothesized a single equation derived from an M/G/∞ renewal process could explain rotor and wavelet numbers in VF. Phase singularity (PS) and wavefront (WF) tracking was used to identify wavelets and rotors in epicardial recordings of induced VF during cardiac surgery (n=13 patients). Autocorrelation and distributions of PS and WF lifetimes and inter-formation times were assessed to verify an underlying renewal process. Distributions were fitted using maximum likelihood to calculate formation (λf) and destruction (λd) rates, and combined in an M/G/∞ process to develop a potential governing equation of VF dynamics. PS and WF inter-event-time distributions were consistent with the Weibull in all 210 epochs (PS: mean Χ2 P=0.23(95%CI,0.18,0.28); WF: mean Χ2 P=0.19(95%CI,0.13,0.27)), with zero autocorrelation at non-zero lags, indicative of an underlying renewal process over all stages (perfusion, ischemia and reflow). The M/G/∞ equation accurately predicted average PS and WF number (R>0.90) and population distribution (Χ2 P>0.05) in all epochs. Differences in λf (term: 0.015/ms (95%CI,0.010,0.020), non-term 0.023/ms (95%CI,0.019,0.027)), and average PS number (term: 1.68 (95%CI, 1.36, 2.00), non-term: (2.00 (95%CI, 1.86, 2.15)) was observed in spontaneous VF termination. M/G/∞ renewal process provides a governing equation to explain the number of wavelets and rotors in VF, which could be used in mechanistic studies to guide development of new therapies.

Objectives: SARS-CoV-2 has challenged health service provision worldwide. This work evaluates safe surgical pathways and standard operating procedures implemented in the high volume, global city of London during the first wave of SARS-CoV-2 infection. We also assess the safety of minimally invasive surgery(MIS) for anatomical lung resection. Methods: This multicentre cohort study was conducted across all London thoracic surgical units, covering a catchment area of approximately 14.8 Million. A Pan-London Collaborative was created for data sharing and dissemination of protocols. All patients undergoing anatomical lung resection 1st March-1st June 2020 were included. Primary outcomes were SARS-CoV-2 infection, access to minimally invasive surgery, post-operative complication, length of intensive care and hospital stay (LOS), and death during follow up. Results: 352 patients underwent anatomical lung resection with an median age of 69 (IQR: 35-86) years. Self-isolation and pre-operative screening were implemented following the UK national lockdown. Pre-operative SARS-CoV-2 swabs were performed in 63.1% and CT imaging in 54.8%. 61.7% of cases were performed minimally invasively. Median LOS was 6 days. Significant complications developed in 7.3% of patients (Clavien-Dindo Grade 3-4). There were 6 deaths(1.7%) and 12 re-admissions(3.4%). Seven patients(2.0%) were diagnosed with SARS-CoV-2 infection, two of whom died (28.5%). Conclusions: Major elective surgery can be safely undertaken via open and MIS approaches at the peak of a viral pandemic if precautionary measures are implemented. High volume surgery should continue during further viral peaks to minimise health service burden and potential harm to cancer patients.Funding Statement: Nil.Declaration of Interests: None of the authors have conflict of interests to declare.Ethics Approval Statement: Institutional approval was obtained from all Trusts contributing to the collaborative. Approval was granted by each hospital trust for data sharing, collaborative work and retrospective review. Formal individual informed consent was not required due to the retrospective nature of the study.

Diagnostic and therapeutic interventions on the esophagus or adjacent organs are responsible for nearly half of all esophageal perforations. If not recognized at the time of the injury, iatrogenic esophageal perforations can present insidiously and lead to delay in diagnosis, thereby increasing morbidity and mortality. Acute clinical awareness is vital for prompt diagnosis, which is usually confirmed with contrast esophagography and contrast-enhanced computed tomography. After establishment of diagnosis, treatment should be promptly initiated and include fluid-volume resuscitation, cessation of oral intake, nasogastric tube insertion, broad-spectrum antibiotics and analgesia. Primary repair, when feasible, is the treatment of choice. Additional procedures beyond primary repair, such as relief of concomitant obstruction, may be necessary if there is underlying esophageal pathology. Drainage alone can be performed for perforations of the cervical esophagus that cannot be visualized. Esophageal T-tube placement or exclusion and diversion techniques are appropriate in clinically unstable patients and in cases where primary repair is precluded either due to preexisting esophageal disease or extensive esophageal damage. Esophagectomy should be performed in patients with malignancy, end-stage benign esophageal disease or extensive esophageal damage that precludes repair. Endoscopic techniques, including stenting, clipping or vacuum therapy, can be used in select cases. Finally, nonoperative management should be reserved for patients with contained esophageal perforations, limited extralumin al soilage and no evidence of systemic inflammation.

Background: Two million non-emergency surgeries are being cancelled globally every week due to the COVID-19 pandemic, which will have a major impact on patients and healthcare systems. Methods: During the peak of the pandemic in the United Kingdom, we set up a multicentre cancer network amongst 14 National Health Service institutions, performing urological, thoracic, gynaecological and general surgical urgent and cancer operations at a central COVID-19 cold site. This is a cohort study of 500 consecutive patients undergoing surgery in this network. The primary outcome was 30-day mortality from COVID-19. Secondary outcomes included all-cause mortality and post-operative complications at 30-days. Results: 500 patients underwent surgery with median age 62.5 (IQR 51-71). 65% were male, 60% had a known diagnosis of cancer and 61% of surgeries were considered complex or major. No patient died from COVID-19 at 30-days. 30-day all-cause mortality was 3/500 (1%). 10 (2%) patients were diagnosed with COVID-19, 4 (1%) with confirmed laboratory diagnosis and 6 (1%) with probable COVID-19. 33/500 (7%) of patients developed Clavien-Dindo grade 3 or higher complications, with 1/33 (3%) occurring in a patient with COVID-19. Conclusion: It is safe to continue cancer and urgent surgery during the COVID-19 pandemic with appropriate service reconfiguration.

Trauma represents the leading cause of death in patients younger than 45 years old. The introduction of multidisciplinary trauma teams has resulted in an improvement in patients` outcome. The thoracic surgeon plays an invaluable role as a member of the multidisciplinary team that includes an emergency physician, surgical figure, an anaesthetist, a radiology technician plus a number of nurses. Thorough knowledge of the physiological mechanism of injury and an intensive training have contributed massively in improving the outcomes. Different surgical approaches have to be considered in order to provide the best outcome to the acute patient with chest injury.

Background Two million non-emergency surgeries are being cancelled globally every week due to the COVID-19 pandemic, which will have a major impact on patients and healthcare systems. Objective To determine whether it is feasible and safe to continue non-emergency surgery in the COVID-19 pandemic Design, setting and participants This is a cohort study of 500 consecutive patients undergoing non-emergency surgery in a dedicated COVID-19 cold site following the first case of COVID-19 that was reported in the institution. The study was carried out during the peak of the pandemic in the United Kingdom, which currently has one of the highest number of cases and deaths from COVID-19 globally. We set up a hub-and-spoke surgical network amongst 14 National Health Service institutions during the pandemic. The hub was a cancer centre, which was converted into a COVID-19 cold site, performing urological, thoracic, gynaecological and general surgical operations. Outcomes The primary outcome was 30-day mortality from COVID-19. Secondary outcomes included all-cause mortality and post-operative complications at 30-days. Results 500 patients underwent surgery with median age 62.5 (IQR 51-71). 65% were male and 60% had a known diagnosis of cancer. 44% of surgeries were performed with robotic or laparoscopic assistance and 61% were considered complex or major operations. None of the 500 patients undergoing surgery died from COVID-19 at 30-days. 30-day all-cause mortality was 3/500 (1%). 10 (2%) patients were diagnosed with COVID-19, 4 (1%) with confirmed laboratory diagnosis and 6 (1%) with probable COVID-19. 33/500 (7%) of patients developed Clavien-Dindo grade 3 or higher complications, with 1/33 (3%) occurring in a patient with COVID-19. Conclusion It is safe to continue non-emergency surgery during the COVID-19 pandemic with appropriate service reconfiguration.

Diagnostic and therapeutic interventions on the esophagus or adjacent organs are responsible for nearly half of all esophageal perforations. If not recognized at the time of the injury, iatrogenic esophageal perforations can present insidiously and lead to delay in diagnosis, thereby increasing morbidity and mortality. Acute clinical awareness is vital for prompt diagnosis, which is usually confirmed with contrast esophagography and contrast-enhanced computed tomography. After establishment of diagnosis, treatment should be promptly initiated and include fluid-volume resuscitation, cessation of oral intake, nasogastric tube insertion, broad-spectrum antibiotics and analgesia. Primary repair, when feasible, is the treatment of choice. Additional procedures beyond primary repair, such as relief of concomitant obstruction, may be necessary if there is underlying esophageal pathology. Drainage alone can be performed for perforations of the cervical esophagus that cannot be visualized. Esophageal T-tube placement or exclusion and diversion techniques are appropriate in clinically unstable patients and in cases where primary repair is precluded either due to preexisting esophageal disease or extensive esophageal damage. Esophagectomy should be performed in patients with malignancy, end-stage benign esophageal disease or extensive esophageal damage that precludes repair. Endoscopic techniques, including stenting, clipping or vacuum therapy, can be used in select cases. Finally, nonoperative management should be reserved for patients with contained esophageal perforations, limited extraluminal soilage and no evidence of systemic inflammation.

INTRODUCTION: Carcinoma of unknown primary is a well-recognized clinical syndrome which accounts for the 3-5% of all the malignancies. Patients with carcinoma of unknown primary usually present with late stage disease without having identified the primary source of the tumour despite an extensive diagnostic work-up. PRESENTATION OF CASE: A 60 years old male presented to the clinic complaining of a neck mass to the left lateral neck. Patient's history was unremarkable without evidence of any malignant disease. Clinical and radiological examination revealed a cystic mass extending from the lower one third of the neck to the left clavicle causing periostal reaction. Mass biopsy and PET-CT was unspecific for the primary origin of the mass. However in the context of tumour immunohistochemistry, HPV status, neck location and basaloid cell differentiation, the tumour mass was considered as carcinoma of unknown primary with possible oropharyngeal primary location. The patient underwent surgical resection of the mass, left clavicle and the first rib. One year after the operation the patient is disease free. DISCUSSION: Although CUP usually presents with cervical lyphadenopathy, in our case there was no evidence of lymph node tissue infiltration in the neck region. Surgical resection of the mass showed that the location was extending within the cervical soft tissues and upper thorax. Taking into consideration the absence of lymphadenopathy this is an uncommon location of carcinoma of unknown primary in the neck. CONCLUSION: This is an uncommon location of CUP with possible implications in survival and management. (C) 2019 Published by Elsevier Ltd on behalf of IJS Publishing Group Ltd.

Abstract Aims Action potential duration (APD) alternans is an established precursor or arrhythmia and sudden cardiac death. Important differences in fundamental electrophysiological properties relevant to arrhythmia exist between experimental models and the diseased in vivo human heart. To investigate mechanisms of APD alternans using a novel approach combining intact heart and cellular cardiac electrophysiology in human in vivo. Methods and results We developed a novel approach combining intact heart electrophysiological mapping during cardiac surgery with rapid on-site data analysis to guide myocardial biopsies for laboratory analysis, thereby linking repolarization dynamics observed at the organ level with underlying ion channel expression. Alternans-susceptible and alternans-resistant regions were identified by an incremental pacing protocol. Biopsies from these sites (n = 13) demonstrated greater RNA expression in Calsequestrin (CSQN) and Ryanodine (RyR) and ion channels underlying IK1 and Ito at alternans-susceptible sites. Electrical restitution properties (n = 7) showed no difference between alternans-susceptible and resistant sites, whereas spatial gradients of repolarization were greater in alternans-susceptible than in alternans-resistant sites (P = 0.001). The degree of histological fibrosis between alternans-susceptible and resistant sites was equivalent. Mathematical modelling of these changes indicated that both CSQN and RyR up-regulation are key determinants of APD alternans. Conclusion Combined intact heart and cellular electrophysiology show that regions of myocardium in the in vivo human heart exhibiting APD alternans are associated with greater expression of CSQN and RyR and show no difference in restitution properties compared to non-alternans regions. In silico modelling identifies up-regulation and interaction of CSQN with RyR as a major mechanism underlying APD alternans.

This case study looks at Long term complications of thoracotomy- chest wall paraesthesia and neuralgic chest pain , and provides questions with model answers.

In this paper, we present a novel approach to quantify the spatio-temporal organization of electrical activation during human ventricular fibrillation (VF). We propose three different methods based on correlation analysis, graph theoretical measures and hierarchical clustering. Using the proposed approach, we quantified the level of spatio-temporal organization during three episodes of VF in ten patients, recorded using multi-electrode epicardial recordings with 30 s coronary perfusion, 150 s global myocardial ischaemia and 30 s reflow. Our findings show a steady decline in spatio-temporal organization from the onset of VF with coronary perfusion. We observed transient increases in spatio-temporal organization during global myocardial ischaemia. However, the decline in spatio-temporal organization continued during reflow. Our results were consistent across all patients, and were consistent with the numbers of phase singularities. Our findings show that the complex spatio-temporal patterns can be studied using complex network analysis.

This case study looks at Left pneumonectomy in a 25 year old with carcinoid tumour, and provides questions with model answers.

This case study looks at Postoperative care of 60 year old man with Squamous cell carcinoma but with severe COPD and no other co-morbidities, and provides questions with model answers.

Oxford Case Histories in Lung Cancer contains 40 well-structured cases from clinical practice that give a comprehensive coverage of both commonly faced situations in clinical practice and incidents that pose particular challenges. Split into five sections, covering epidemiology, medical and clinical oncology, thoracic surgery, and palliative care, each case comprises a brief clinical history with relevant clinical examination findings. Questions are based on clinical investigations and aspects of management. Detailed answers follow, based on the best available evidence from the latest research, systematic reviews, meta-analyses, and guidelines. The resource is illustrated with over 75 pictures and diagrams.

Background: Acquired aerodigestive fistula (ADF) are rare, but associated with significant morbidity. Surgery affords the best prospect of cure. We present our experience of the surgical management of ADFs at a specialist unit, highlighting operative techniques, challenges and assess clinical outcomes following intervention. We also illustrate findings of a Hospital Episodes Statistics search for ADFs. Methods: A prospectively-maintained database was searched to identify all patients diagnosed with an ADF who were managed at our institution. Of 48 patients with an ADF, eight underwent surgical intervention. Results: Four patients underwent an exploration of the ADF with primary repair of the defect. Two of these patients had proximal ADFs, amenable to repair through a neck incision, and two required a thoracotomy. Two patients suffered fistulae secondary to endoscopic therapy and underwent oesophageal exclusion surgery, with subsequent staged reconstruction. Two patients with previous Tuberculosis had a lung segmentectomy and lobectomy respectively, and a further patient in remission after treatment for lymphoma underwent oesophageal resection with synchronous reconstruction. Three patients suffered a complication, with one post-operative mortality. The remaining seven patients all achieved normal oral alimentation, with no evidence of ADF recurrence at a median follow-up of 32months. Conclusions: Surgery to manage ADFs is effective in restoring normal alimentation and alleviates soiling of the airway, with a very low risk of recurrence. Several operative techniques can be utilised dependent on the features of the ADF. Early referral to specialist units is advocated, where the expertise to facilitate the complete management of patients is present, within a multi-disciplinary setting.

This case study looks at Preoperative assessment and fitness for surgery- T2N0 M0 Left hilar squamous cell carcinoma in lady with severe COPD, and provides questions with model answers.