Publications by authors named "Alison Knaggs"

Introduction: Oesophagectomy is a major surgical procedure, associated with high rates of postoperative cardiopulmonary morbidity, that is in part due to the frequent requirement for periods of intraoperative one-lung ventilation (OLV). The current pilot study aims to investigate variation in exhaled NO levels during oesophagectomy with emphasis on the response to OLV and correlation to physiological variables and clinical outcomes.

Methods: Breath-to-breath concentrations of NO were analysed in patients undergoing oesophagectomy at various stages of two-lung ventilation.

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Background: The aim of this study was to determine the safety of anti-reflux surgery for lung transplant recipients and assess its effect on lung function.

Methods: We retrospectively collected and analyzed data from all lung transplant recipients who underwent anti-reflux surgery at St Mary's Hospital London from July 2005 to May 2012. The indications for surgery were histologic evidence of gastroesophageal reflux aspiration on bronchoscopy biopsy specimens or a positive impedance study with symptomatic reflux or a consistent decline/fluctuating forced expiratory volume in 1 second (FEV(1)).

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Hypothesis: Extended lymphadenectomy in gastroesphageal cancer leads to improved long-term survival without compromising postoperative outcomes in Western patients to attain the standard achieved in Japanese centers.

Design: Cohort study comparing postoperative outcomes and long-term survival with data from the National Cancer Center (NCC) of Tokyo, Japan. Outcomes were also compared with data from the UK National Oesophago-Gastric Cancer Audit (NOGCA) and a representative cohort from southeast England.

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A study is described of the first on line, real time analyses of the exhaled breath of five anaesthetized patients during the complete perioperative periods of laparoscopic surgery. These breath analyses were achieved using a selected ion flow tube, SIFT-MS, instrument, located in the operating theatre at an acceptable distance from the operating table, and coupled to the endotracheal tube in the ventilation circuit via a 5 metre long capillary tube. Thus, inhalation/exhalation breathing cycles, set to be at a frequency of 10 per minute, were sampled continuously for water vapour, the metabolites acetone and isoprene and the propofol used to induce anaesthesia for each operating period that ranged from 20 min (shortest) to 80 min (longest).

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Background: A large tortuous vein coursing over the posterior aspect of the knee and the upper calf may give rise to a constellation of varicose veins unrelated to the great (GSV) or small (SSV) saphenous veins. Designated the popliteal fossa vein (PFV), it perforates the deep popliteal fascia and empties into the deep system. We examined the prevalence, anatomic reflux patterns, hemodynamic role, and clinical significance of the PFV.

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Purpose: By acutely enhancing the arterial leg inflow, intermittent pneumatic leg compression (IPC) improves the walking ability, arterial hemodynamics, and quality of life of claudicants. We quantified the duration of acute leg inflow enhancement with IPC of the foot (IPC(foot)), calf (IPC(calf)), or both (IPC(foot+calf)) and its amplitude decay in claudicants and controls in relation to the pulsatility index, an estimate of peripheral resistance. These findings are cross-correlated with the features of the three implicated physiologic mechanisms: (1) an increase in the arteriovenous pressure gradient, (2) suspension of peripheral sympathetic autoregulation, and (3) enhanced release of nitric oxide with flow and shear-stress increase.

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Objective: Coursing the posterior thigh as a tributary or trunk projection of the small saphenous vein (SSV), the Giacomini vein's clinical significance in chronic venous disease (CVD) remains undetermined. This cross-sectional controlled study examined the prevalence, anatomy, competency status, and clinical significance of the Giacomini vein across the clinical spectrum of CVD in relation to the SSV termination.

Methods: One hundred eighty-nine consecutive subjects (301 limbs) with suspected CVD (109 men, 80 women; age, 18-87 years [median, 61 years]) underwent examination, clinical class (CEAP) stratification, and duplex ultrasound determination of the sites and extent of reflux >0.

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Our hypothesis was that, due to its sympatholytic action, epidural anesthesia (EA) administered as part of anesthesia in abdominal surgery would generate a marked venous leg flow enhancement, thus aiding in the prevention of peroperative venous stasis. We studied, and comprehensively quantified the venous haemodynamic changes in the lower limb during and immediately after abdominal surgery performed under EA and general (GA) anesthesia combined, in comparison to GA alone. This is a prospective, randomized, controlled study, stratified for hypertension and smoking, comprising ASA 1-2 patients undergoing elective total abdominal hysterectomy.

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The role of stasis in venous disease is undisputed, yet surprisingly, its haemodynamic quantitation remains largely undefined. We investigated the phenomenon of venous stasis in the lower limb upon sitting and standing and project its implications to economy class aircraft passengers. 26 normal limbs, 13 subjects, age 29-54, selected after duplex, plethysmography and ABPI, had peak[V(peak)], mean[V(mean)] and minimum[V(min)] velocities, volume-flow[Q(venous)], pulsatility index [PI(venous)] and diameter obtained on horizontal, sitting (as in economy aircraft seats) and standing with duplex, at popliteal, femoral[FV] and common femoral[CFV]veins [differences in median %].

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