Proton beam dosimetry in the presence of magnetic fields using Farmer-type ionization chambers of different radii

BACKGROUND

Magnetic resonance-guided proton therapy is promising, as it combines high-contrast imaging of soft tissue with highly conformal dose delivery. However, proton dosimetry in magnetic fields using ionization chambers is challenging since the dose distribution as well as the detector response are perturbed.

PURPOSE

This work investigates the effect of the magnetic field on the ionization chamber response, and on the polarity and ion recombination correction factors, which are essential for the implementation of a proton beam dosimetry protocol in the presence of magnetic fields.

METHODS

Three Farmer-type cylindrical ionization chambers, the 30013 with 3 mm inner radius (PTW, Freiburg, Germany) and two custom built chambers "R1" and "R6" with 1 and 6 mm inner radii respectively were placed at the center of an experimental electromagnet (Schwarzbeck Mess - Elektronik, Germany) 2 cm depth of an in-house developed 3D printed water phantom. The detector response was measured for a 3×10 cm² field of mono-energetic protons 221.05 MeV/u for the three chambers, and with an additional proton beam of 157.43 MeV/u for the chamber PTW 30013. The magnetic flux density was varied between 0.1 and 1.0 Tesla in steps of 0.1 Tesla.

RESULTS

At both energies, the ionization chamber PTW 30013 showed a non-linear response as a function of the magnetic field strength, with a decrease of the ionization chamber response of up to 0.27±0.06% (1 SD) at 0.2 Tesla, followed by a smaller effect at higher magnetic field strength. For the chamber R1, the response decreased slightly with the magnetic field strength up to 0.45±0.12% at 1 Tesla, and for the chamber R6, the response decreased up to 0.54±0.13% at 0.1 Tesla, followed by a plateau up to 0.3 Tesla, and a weaker effect at higher magnetic field strength. The dependence of the polarity and recombination correction factor on the magnetic field was ≤ $ \le $ 0.1% for the chamber PTW 30013.

CONCLUSIONS

The magnetic field has a small but significant effect on the chamber response in the low magnetic field region for the chamber PTW 30013 and for R6, and in the high magnetic field region for the chamber R1. Corrections may be necessary for ionization chamber measurements, depending on both the chamber volume and the magnetic flux density. No significant effect of the magnetic field on the polarity and recombination correction factor was detected in this work for the ionization chamber PTW 30013. This article is protected by copyright. All rights reserved.

Increasing the use of perioperative risk scoring in emergency laparotomy: nationwide quality improvement programme

Background

Emergency laparotomy is associated with high morbidity and mortality. The early identification of high-risk patients allows for timely perioperative care and appropriate resource allocation. The aim of this study was to develop a nationwide surgical trainee-led quality improvement (QI) programme to increase the use of perioperative risk scoring in emergency laparotomy.

Methods

The programme was structured using the active implementation framework in 15 state-funded Irish hospitals to guide the staged implementation of perioperative risk scoring. The primary outcome was a recorded preoperative risk score for patients undergoing an emergency laparotomy at each site.

Results

The rate of patients undergoing emergency laparotomy receiving a perioperative risk score increased from 0–11 per cent during the exploratory phase to 35–100 per cent during the full implementation phase. Crucial factors for implementing changes included an experienced central team providing implementation support, collaborator engagement, and effective communication and social relationships.

Conclusions

A trainee-led QI programme increased the use of perioperative risk assessment in patients undergoing emergency laparotomy, with the potential to improve patient outcomes and care delivery.

212 BUILT ENVIRONMENT OF NURSING HOMES AND INFECTION CONTROL AND PANDEMIC PREPAREDNESS

Background

The disproportionately high death rate of nursing home (NH) residents from COVID-19 in many countries, including Ireland, has focussed attention on infection prevention and control, including the built environment, in nursing homes. This has been a poorly researched topic to date, and we undertook a systematic review of evidence for architectural design measures which support infection control and pandemic preparedness.

Methods

Databases were screened for keywords related to NHs, built environment, infection prevention and control, and COVID-19; relevant papers were uploaded onto Covidence and screened for relevance. Data extracted from included articles was tabulated under 8 specific aspects of the built environment.

Results

Of 17 papers included in the final analysis, four studies found that larger nursing homes carried an increased risk of COVID-19 infection. Crowding in NHs was also a risk factor for infection, with a high crowding index associated with COVID-19 infection in five studies. Green House care homes, which are based on small clusters of domestic dwellings, fared better than traditional NHs. Two papers found an association between the location of NHs and the risk of COVID-19 infection, with urban NHs and those in areas of high prevalence being more at risk. Two papers identified internal fittings as a target for infection prevention and control. Seven papers highlighted the role of adequate ventilation in NHs in the prevention of spread of COVID-19. Only one paper described easy access to the outdoors as beneficial to infection control.

Conclusion

Residents of NHs are amongst the most vulnerable to COVID-19 infection. When designing and building NHs, the role of the built environment in controlling the spread of the virus should not be underestimated.

This research supported by Science Foundation Ireland.

The politics of COVID-19 on the island of Ireland

Background

Political systems are the means through which the science of public health achieves its objectives. This is a qualitative study of public health policies for COVID-19 in Northern Ireland and the Republic of Ireland that seeks to establish if inter-jurisdictional commitments have led to co-ordination and co-operation on the island of Ireland.

Methods

10 indicators from the OxCGRT codebook directed data collection with directed qualitative content analysis supporting comprehensive reading of policy documents. Cross-case and within-case analysis of policy alignment and divergence across ten OxCGRT indicators was undertaken.

Results

Closing Schools Republic of Ireland: 12th March 2020 Northern Ireland: 23rd March 2020; Workplace Closing - Republic of Ireland: 12th and 15th March and 24th March 2020. Northern Ireland: 20th March 2020 followed by mandatory closure on 28th March 2020. Cancelling events and mass gatherings (St Patrick's Day, 17th March)-Republic of Ireland: 9th March 2020-Northern Ireland: 9th March 2020;Lockdown/Shelter-in-place policies. Republic of Ireland: 27th March 2020- Northern Ireland: 28th March 2020; Restrictions on Internal Movement Republic of Ireland: 27th March 2020 Northern Ireland: 28th March 2020. Physical Distancing Measures -Republic of Ireland: 2-metres 24th March 2020 Northern Ireland: 2 metres 23rd March 2020. Mandatory Face Masks in Enclosed Spaces-Republic of Ireland: 10th August 2020 -Northern Ireland: 10th August 2020.

Conclusions

The historical and constitutional politics of the island of Ireland is the obstacle to an all-island response to COVID-19 and this has almost certainly been compounded by Brexit. Defying the odds, however, this study has demonstrated substantial public health policy alignment brought about through ongoing dialogue and co-operation between the health administrations in each jurisdiction.

Key messages

Historical and constitutional politics of the island of Ireland is the obstacle to an all-island response to COVID-19. Even pandemics cannot overcome realpolitik.

Process evaluation of We Can Quit- stop-smoking programme for women in socio-disadvantage in Ireland

Background

Smoking tobacco poses a serious risk of early preventable death and disease for women living with socioeconomic disadvantage (SED). A smoking cessation programme ‘We Can Quit' (WCQ) tailored to women living in four SED areas developed in Ireland included group support delivered by trained lay local women and free nicotine replacement therapy (NRT). The intervention was pilot tested in a community-based, cluster randomised controlled trial, ‘We Can Quit 2'. Results of an embedded process evaluation to assess feasibility and acceptability of the programme and trial processes are presented.

Methods

The design was qualitative using the Medical Research Council's (MRC) process evaluation framework. Semi-structured interviews with trial participants (N = 18) and Community Facilitators (CFs) who delivered WCQ (N = 8) were conducted. An inductive approach was used and data were analysed using thematic coding.

Results

Peer-modelling, a non-judgemental environment, and CFs supportive role were viewed as facilitative elements of group support. Potential for broader message diffusion into the social networks of participating women was observed. Participants reported that free access to NRT was helpful for cessation. Some participants expressed concerns about NRT side effects. Community pharmacists provided important guidance relating to NRT and additional support between group sessions. Provision of a saliva samples proved challenging. Low literacy was a barrier to engagement with the programme and completion of trial-related materials. Hypothetical scenarios of direct or indirect observational fidelity assessment for a definitive trial (DT) were acceptable.

Conclusions

The MRC framework proved useful to capture the experience of women smokers in SED areas of engaging with a community-based smoking cessation trial. Programme and trial-related processes were feasible and acceptable. A future DT will need to address low literacy.

Key messages

A group-based stop-smoking programme including free NRT was acceptable and feasible to programme deliverers and women smokers living in disadvantaged communities. Women’s low literacy was a barrier to engagement with trial and completion of programme materials.

359 Incidental Fatty Liver Disease; Are We Adhering to Guidelines?

Aim

Hepatic steatosis is an increasingly prevalent condition, with estimates of up to 30% amongst western populations. Fatty liver is a common incidental finding on abdominal imaging. Current British Society of Gastroenterology guidelines suggest the use of scoring systems, such as FIB-4 or NFS, to stratify these patients into risk categories for the development of non-alcoholic steatohepatitis, and subsequent liver failure or hepatocellular carcinoma. We carried out an audit of our own practice, to see if these guidelines were being followed.

Method

We interrogated the national imaging management system to identify all scans performed in Wexford general hospital from 16th April to 16th October 2020 which identified “hepatic steatosis” or “fatty liver”. Data extracted included: patient demographics, imaging modality & finding. We correlated this data with the patient’s LFTs to calculate their FIB-4/NFS score and investigated whether suitable patients had been referred to gastroenterology.

Results

Of the 145 patients identified as having hepatic steatosis on imaging, 65 (44.8%) had ALT derangement, 42 (29%) had ALP derangement, 81 (56%) had GGT derangement and 23 (16%) had an elevated total bilirubin. Only 26 (17.9%) of these patients had evidence of subsequent liver serology studies, and only 11 (7.6%) had been referred to gastroenterology. None of the patient cohort had either a FIB-4 or NFS score calculated.

Conclusions

There is clear evidence that guidelines are not being followed in the management of patients who are incidentally found to have hepatic steatosis.

Outcomes of renal replacement therapy in the critically ill with COVID-19

Objective

To describe outcomes of critically ill patients with COVID-19, particularly the association of renal replacement therapy to mortality.

Design

A single-center prospective observational study was carried out.

Setting

ICU of a tertiary care center.

Patients

Consecutive adults with COVID-19 admitted to the ICU.

Intervention

Renal replacement therapy.

Main variables of interest

Demographic data, medical history, illness severity, type of oxygen therapy, laboratory data and use of renal replacement therapy to generate a logistic regression model describing independent risk factors for mortality.

Results

Of the total of 166 patients, 51% were mechanically ventilated and 26% required renal replacement therapy. The overall hospital mortality rate was 36%, versus 56% for those requiring renal replacement therapy, and 68% for those with both mechanical ventilation and renal replacement therapy. The logistic regression model identified four independent risk factors for mortality: age (adjusted OR 2.8 [95% CI 1.8–4.4] for every 10-year increase), mechanical ventilation (4.2 [1.7–10.6]), need for continuous venovenous hemofiltration (2.3 [1.3–4.0]) and C-reactive protein (1.1 [1.0–1.2] for every 10 mg/L increase).

Conclusions

In our cohort, acute kidney injury requiring renal replacement therapy was associated to a high mortality rate similar to that associated to the need for mechanical ventilation, while multiorgan failure necessitating both techniques implied an extremely high mortality risk.

379 The Critical Care Experience of Irish Surgical Non-Consultant Hospital Doctors, Are We Equipped to Assist During the Covid-19 Outbreak and Beyond?

Introduction

The ongoing COVID-19 pandemic has presented unforeseen threats and stresses to healthcare systems around the world, most notably in the ability to provide critical care.

Aim

To assess surgical NCHD experience in providing critical care and working in an intensive care environment.

Method

An electronic survey was distributed amongst surgical trainees and then amongst individual surgical departments. Ten questions were included in the survey assessing the NCHD’s experience with aspects of critical care.

Results

39 respondents including 16 specialist registrars, 3 senior registrars, 11 registrars and 9 senior house officers. 18% of respondents had previous experience in anaesthetics or intensive care. 23% self-reported being competent in performing endotracheal intubation. 15% self-reported being competent in the use of CPAP and BiPaP, 5% did not know what these were. 20% self-reported being competent in the use of AIRVO. 15% self-reported being competent in placing central and arterial lines. 15% self-reported being competent in starting and adjusting inotropes/vasopressors. 49% reported completing a CCRISP or BASIC course. 85% felt that a rotation in anaesthesia should be a routine part of surgical training.

Conclusions

Whilst there is critical care experience amongst the surgical NCHD cohort there remains room for further development.

378 The Future Potential of Artificial Intelligence in Upper Gastrointestinal Endoscopy, A Scoping review

Introduction

The use of Artificial Intelligence (AI) in medicine is accelerating. Recently there have been significant advancements made in its role in upper GI endoscopy.

Aim

To assess current research questions exploring the use of AI in diagnosing upper GI pathology at endoscopy.

Method

A scoping review of studies published on PubMed over the last 5 years using the search string: (((artificial intelligence) OR AI)) AND (Gastroscopy OR OGD OR EGD OR oesophagus OR esophagus OR stomach OR Gastric) was conducted.

Inclusion criteria: retrospective and prospective studies, published in the English language. Data extracted: country of origin for the research, clinical question, demographics, form of AI and study design.

Results

Search run on 5thof February 2020 yielded 2542 results. Articles meeting inclusion criteria numbered 25. Research originated in Japan (32%), Europe (24%), China (20%), South Korea (8%), other (16%). Clinical questions being explored included: use of AI for detecting gastric cancer, assessing depth of gastric cancer invasion, detecting early neoplasia in Barrett’s Oesophagus, real time gastric polyp detection and H.Pylori infection status.

Conclusions

AI use in upper GI endoscopy is being evaluated at an increasing rate. Surgeons must be ready to gain a working knowledge of this technology to safely interpret its results.

381 Is There A Role for Tranexamic Acid in Upper GI Bleeding? A Systematic Review and Meta-Analysis

Introduction

Upper Gastrointestinal bleeding is associated with increased morbidity and mortality. It has been suggested that tranexamic acid (TXA) may be useful in arresting bleeding.

Aim:

To synthesise available evidence of the effect of TXA on upper GI bleeding.

Method

A systematic review was conducted. PubMed, EMBASE and Cochrane central register of controlled trials were searched for relevant studies. A random effects meta-analysis was performed to determine the risk ratio of primary and secondary outcomes.

Results

8 studies were included in the review. Total number of patients included was 12994 including 4550 females (35%). The effect of TXA on mortality: risk ratio was 0.95 which favoured TXA however the 95% CI ranged from 0.80 to 1.13 and was not statistically significant. The re-bleeding rate risk ratio was 0.64, which favoured the TXA group and with a 95% CI ranging from 0.47 to 0.86 this was statistically significant. The risk of adverse thromboembolic events: risk ratio was 0.93 favoured the TXA group however the 95% CI extended from 0.62 to 1.39 and so was not statistically significant.

Conclusions

We cannot recommend the routine use of TXA in the setting of acute upper GI bleeding outside its use in randomised controlled clinical trials.

Outcomes of renal replacement therapy in the critically ill with COVID-19

Objective

To describe outcomes of critically ill patients with COVID-19, particularly the association of renal replacement therapy to mortality.

Design

A single-center prospective observational study was carried out.

Setting

ICU of a tertiary care center.

Patients

Consecutive adults with COVID-19 admitted to the ICU.

Intervention

Renal replacement therapy.

Main variables of interest

Demographic data, medical history, illness severity, type of oxygen therapy, laboratory data and use of renal replacement therapy to generate a logistic regression model describing independent risk factors for mortality.

Results

Of the total of 166 patients, 51% were mechanically ventilated and 26% required renal replacement therapy. The overall hospital mortality rate was 36%, versus 56% for those requiring renal replacement therapy, and 68% for those with both mechanical ventilation and renal replacement therapy. The logistic regression model identified four independent risk factors for mortality: age (adjusted OR 2.8 [95% CI 1.8–4.4] for every 10-year increase), mechanical ventilation (4.2 [1.7–10.6]), need for continuous venovenous hemofiltration (2.3 [1.3–4.0]) and C-reactive protein (1.1 [1.0–1.2] for every 10 mg/L increase).

Conclusions

In our cohort, acute kidney injury requiring renal replacement therapy was associated to a high mortality rate similar to that associated to the need for mechanical ventilation, while multiorgan failure necessitating both techniques implied an extremely high mortality risk.

Optimising the management of concurrent symphyseal/parasymphyseal and bilateral extracapsular condylar fractures using three-dimensional printing

PURPOSE

Three-dimensional (3D) printing plays an important role in the diagnosis and treatment planning of many elective procedures in oral and maxillofacial surgery (OMFS). 3D printers and the associated print materials are now within the price range of most maxillofacial units, requiring less work to be sent out to commercial printers. Whilst their use in the planning of elective procedures is commonplace, acute trauma is an area where 3D printing remains underutilised. The successful management of complex fracture patterns such as concomitant symphyseal/parasymphyseal and bilateral condylar fractures often warrants this approach.

METHODS

Freeware digital processing and manipulation software packages were used to view and segment structures from computed tomography (CT) data. Thereafter, fractures were digitally reduced. 3D printed models were produced from the digitally reduced models, allowing preoperative custom adaptation of osteosynthesis plates, facilitating accurate fracture fixation intraoperatively.

RESULTS

For less than one hundred pounds sterling (STG), a 3D printer (with print material) capable of producing a model of sufficient quality can be purchased. The use of freeware digital processing software allows digital manipulation of CT data. Production of 3D models and plate adaptation can be carried out within hours after CT examination.

CONCLUSIONS

The construction of digitally reduced 3D models and custom adapted plates enables the surgeon to achieve accurate fixation of complex fracture patterns in theatre which is clearly of benefit to patients. The potential for reduced theatre time also renders this approach more desirable, making this a worthwhile investment despite the additional non-clinical time associated with training and initial expenditure.

Surgical Parathyroidectomy Services

Aims Retrospectively audit our experience with surgical parathyroidectomy over a 5 year period from the beginning of 2013 to June 2018. Methods Hospital In-patient Enquiry (HIPE) data, NIMIS radiology and theatre logs were used to identify the study cohort of a single specialist parathyroid surgeon. Demographic data plus pre and post-op calcium and parathyroid Hormone (PTH) levels were analysed. Data were coded and entered into SPSS 24 statistical software package for analysis. Results Thirty-one surgical parathyroidectomy cases were identified comprising four male and twenty seven females. Average age was 59.81 years (SD 14.75). The median pre-op and post-op calcium levels were 2.81[elevated] (Range 2.37-4.06 mmol/L) and 2.42[normal] (2.16-3.31 mmol/L) respectively and were statistically significant therapeutic reductions (p<0.05). The median pre-op and post-op PTH levels were 168.0[elevated] (Range 69-3171 pg/ml) and 41.7 [normal] (7.30-1628 pg/ml) respectively. All patients were discharged on post op day 1. Conclusion Parathyroidectomy is a safe and cost-effective treatment for PHPT in University Hospital Waterford.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Antimicrobial-resistant Faecal Organisms in Algae Products Marketed as Health Supplements

Dietary supplements are increasingly popular in Irish society. One of these is blue-green algae which is used with a variety health benefits in mind. A batch of Chlorella powder was found to be contaminated with Salmonella species in Ireland in 2015. This prompted additional testing of a total of 8 samples of three different products (Chlorella, Spirulina and Super Greens), for other faecal flora and antimicrobial resistance in any bacteria isolated. All 8 samples cultured enteric flora such as Enterococci, Enterobacteriaceae and Clostridium species. Antimicrobial susceptibility testing revealed one isolate with extended-spectrum ?-lactamase (ESBL) activity and one with carbapenemase activity. Clinicians caring for vulnerable patients should be aware of the potential risk of exposure to antimicrobial resistant bacteria associated with these products.

A nonrandomized observational trial of short-term preoperative endocrine therapy in ER-positive breast cancer to investigate change in genomic expression using the 21-gene breast cancer assay

221

Background: Preoperative systemic treatment is commonly employed for women with locally advanced breast cancer. Women with early-stage breast cancer, whose resections may be delayed for 30 to 60 days while they undergo preoperative evaluation, may benefit from receiving preoperative endocrine therapy while awaiting surgery. One rationale for not initiating such treatment is that the cancer may be rendered less chemosensitive. The 21-gene assay is a proven predictor of chemotherapy responsiveness. The objective of this study is to examine the association between recurrence score (RS) and ER, PR, and HER2 RT-PCR values in core biopsy and surgical specimens from patients treated with short term pre-operative endocrine therapy.

Methods: Pre- and postmenopausal women with clinical T1-N0-M0, sonographically visible, ER-positive, HER2-negative breast cancer were eligible. Patients were treated with 4-8 weeks of preoperative endocrine therapy; letrozole if postmenopausal or tamoxifen if premenopausal. Clinical breast examination and ultrasound were conducted every two weeks, with the final ultrasound immediately prior to surgery. Tumor blocks from the core biopsy and surgical excision were submitted to Genomic Health, Inc., where RS, ER, PR, and HER2 results were obtained from each of the paired specimens.

Results: Nineteen matching core biopsy and surgical specimens were available for analysis. Pearson correlation coefficients between core biopsy and excisional sample results were 0.89 for RS, 0.87 for ER, 0.72 for PR, and 0.77 for HER2. On average, small but statistically significant increases in RS and decreases in ER and PR were observed (all p < 0.005 from paired t-test). No obvious associations between these markers and clinical response were observed.

Conclusions: In this small, hypothesis-generating study, paired RS and RT-PCR for ER/PR/HER2 remained correlated after short-term preoperative endocrine therapy. This study provides no suggestion of decreasing chemosensitivity during preoperative endocrine therapy, but additional research is warranted to explore these findings further.

Anti-CD25 treatment and FOXP3-positive regulatory T cells in heart transplantation

The interleukin-2 receptor alpha chain (IL-2Ra, CD25) plays a major part in shaping the dynamics of T cell populations following immune activation, due to its role in T cell proliferation and survival. Strategies to blunt the effector responses in transplantation have been developed by devising pharmaceutical agents to block the IL-2 pathways. However, such strategies could adversely affect the CD25(+)FOXP3(+)T regulatory (T reg) populations which also rely on intereukin-2 signaling for survival. The present study shows that a cohort of heart allograft recipients treated with Daclizumab (a humanized anti-CD25 antibody) display FOXP3 expression patterns consistent with functional T regulatory cell populations. High levels of FOXP3 were observed to correlate with lower incidence of and recovery from acute rejection, as well as lower levels of anti-donor HLA antibody production. Therefore, T reg populations appear fully functional in patients treated with Daclizumab, even when 5 doses were administered. By comparison, patients treated with fewer doses or no Daclizumab had a higher incidence of acute rejection, antibody production and graft failure. Therefore, our data indicates that Daclizumab treatment does not interfere with the generation of regulatory T cells and has a beneficial effect on heart allograft survival.

Impact of chemoradiotherapy for locally advanced head and neck cancer on swallowing function

6054

Background: We examined the impact of chemoradiotherapy (CRT) on swallowing function in a group of patients treated for locally advanced head and neck cancer in an ongoing randomized phase II study with concurrent CRT, with or without Ethyol. Methods: Chemotherapy consisted of weekly carboplatin AUC 1.5 and paclitaxel at 45 /m2 for 4 weeks. Radiation was delivered using a 3 field technique with a concomitant boost schedule to a total dose of 72 Gy. Patients were randomized to receive or not receive daily subcutaneous Ethyol. Patients had video swallow studies at the start of radiation and 8, 12, 24 and 52 weeks post chemoradiotherapy. Dysphagia and weight loss were monitored. Video swallow study reports were collected and the incidence of penetration, aspiration, pharyngeal residue and upper esophageal narrowing analyzed. Results: Baseline data were available for 31 patients out of 43 enrolled. 29% of the patients penetrated, 6.4% aspirated and 29% had pharyngeal residue. Patients on both arms of the study had a steady decline in swallowing function from onset until 24 weeks post radiation. Penetration, aspiration and pharyngeal residue were consistently noted at all time points and improvements in deglutition were seen on the 52-week post radiation video swallow. Forty percent of the patients (17/43) had narrowing in the upper esophagus. On average, a third of the patients examined required dilations. The remaining patients with esophageal narrowing were able to advance their diet and have their feeding tubes removed without dilations. The average time from the end of the treatment to PEG removal was 219 days. Conclusion: Based on the video swallow studies that were conducted, patients had a gradual decline in swallowing function from initiation of CRT until 24 weeks post. Esophageal narrowing was common, often requiring dilation. Given that it takes 7 months on average for the feeding tubes to come out, we recommend that these patients undergo intensive swallowing therapy and continuous long term follow up and assessment at two and possibly three years post CRT. Study is ongoing.

No significant financial relationships to disclose.

Swallowing function after intensity modulated radiotherapy (IMRT) and chemotherapy for head and neck cancer

6046

Background: To evaluate the swallowing function of patients treated with intensity modulated radiation therapy (IMRT) + chemotherapy (CT) for HNSCC. Methods: Patients completing RT between 9/04 and 8/06 at the DFCI/BWH were evaluated with IRB approval. All patients had formal swallowing evaluation following the completion of therapy; patients with swallowing difficulty underwent video swallow and both stricture and aspiration were scored. Variables examined for correlation with swallowing pathology were: age, race, gender, smoking and alcohol history, primary site, LVI, PNI, RT intention (primary, postop) and use of induction CT. All variables were analyzed via two-sided t-test. Results: 96 patients were evaluated. Median follow-up 10 mos. 75% of the pts were given definitive RT and 25% received postop RT. 72% stage IV, 24% stage III. Primary sites: oropharynx-43, hypopharynx/larynx-17, oral cavity-13, nasopharynx-11, maxillary sinus-2 and unknown primary-10 pts. All pts received once daily IMRT. 9 pts received RT alone, 28 pts received sequential induction and concurrent (CT) and 59 pts received concurrent CT. 31 pts (32%) had some aspiration after therapy; 36 pts (37%) had evidence of a stricture following RT. All but 5 patients had percutaneous endoscopic gastrostomy placed prophylactically RT. Smoking history was the only significant factor found on univariate analysis to correlate with stricture (p=0.05) but not aspiration. Induction CT was not a significant factor in causing aspiration or stricture. 22 of the strictures (71%) resolved after dilation. RT doses to swallowing structures are under evaluation and will be presented. Conclusions: Aspiration and stricture are common side effects after radical treatment with IMRT and CT for HNSCC. Smoking has a significant negative impact on functional outcome.

No significant financial relationships to disclose.

Bronchiolitis obliterans organizing pneumonia in a patient with non-Hodgkin's lymphoma following R-CHOP and pegylated filgrastim

Bronchiolitis obliterans organizing pneumonia (BOOP) presents with fever, dyspnoea, pleuritic chest pain and hypoxia. The diagnosis can be made from radiological appearances on chest radiograph and CT scan correlated with histological findings following biopsy. We present a 52-year-old gentleman undergoing treatment for high grade non-Hodgkin's lymphoma who developed respiratory symptoms during chemotherapy. BOOP was diagnosed and he responded well to oral prednisolone. The cause of BOOP is often not certain. However, in this case we suspect pegylated filgrastim or rituximab as possible agents.

In vitro evaluation of B-domain deleted recombinant factor VIII (ReFactoR) stability during simulated continuous infusion administration

The administration of factor VIII (FVIII) by continuous infusion (CI) to manage severe haemorrhage or during major surgery appears pharmacokinetically and economically favourable when compared with intermittent bolus infusions. Successful clinical use of FVIII delivered by CI, however, requires a thorough assessment of product stability under conditions encountered during CI such as prolonged exposure to the delivery devices at ambient temperature and the low FVIII concentrations. This investigation has identified conditions under which ReFacto, a recombinant human B-domain deleted FVIII, can be successfully delivered under dilute conditions when using large volume parenteral polyvinyl chloride (PVC) bags without the addition of stabilizers or as an undiluted preparation delivered by ambulatory infusion pumps. ReFacto is stable for 36 h when stored in large volume parenteral PVC reservoirs at 3 and 8 IU mL(-1) or 72 h when delivered undiluted at 62 IU mL(-1) by CADD infusion pumps. The greatest concern with the delivery of ReFacto by CI is adsorptive losses to the contact surfaces of the delivery system. There was no significant binding of ReFacto to the PVC reservoirs overtime; however, there was appreciable binding to the administration set under certain conditions. The binding was influenced by the ionic strength of the solution, residence time in the tubing and protein concentration. The recovery and stability profile of ReFacto under certain conditions appears favourable when compared with that of full-length recombinant FVIII products, observed by other investigators.

Large sample validations of three general predictors of pilot training success

This article addresses one of the perennial problems of pilot selection research: obtaining an adequate sample size for reliable statistical analysis of predictive validity. Results from three studies involving the same computerized tests of instrument comprehension and psychomotor ability were combined in a meta-analysis to determine whether the validities of these tests generalized across three contexts. These were Royal Air Force and Turkish Air Force fixed-wing pilot training and British Army Air Corps rotary-wing pilot training. In this article, we discuss the adequacy of samples for estimating the validity of the tests, and the persistence of predictive validity to later stages of training as shown by British Army Air Corps data. Reference is also made to data from a fourth independent study of Qantas pilot training.

The Heartmate II: design and development of a fully sealed axial flow left ventricular assist system

Our group is developing the control and power transmission components required to implement a permanent and fully sealed left ventricular assist system (LVAS). Starting with the percutaneously powered HeartMate II blood pump, our development efforts are focused in the following areas: a complete redesign of the transcutaneous energy transmission system (TETS) to include a rectification network and autonomous voltage regulation within the secondary coil, a hermetically sealed electronics package containing a miniaturized implementation of the existing redundant drive and control electronics with several power-input options, an implanted rechargeable lithium ion battery pack capable of providing up to 1 h of untethered operation, implantable electrical connectors that allow components to be connected after placement in the body or to be replaced if needed, and a radio telemetry subsystem to transmit diagnostic information and to permit remote adjustment of selected parameters.