Therapeutic response to bronchial thermoplasty: toward feasibility of patient selection based on modeling predictions

Bronchial thermoplasty (BT) is a treatment for moderate-to-severe asthma in which the airway smooth muscle layer is targeted directly using thermal ablation. Although it has been shown to be safe and effective in long-term follow-up, questions remain about its mechanism of action, patient selection, and optimization of protocol based on structural phenotype. Using a cohort of 20 subjects who underwent thermoplasty and assessment by computed tomography (CT), we demonstrate that response to BT can be feasibly predicted based on pretreatment airway dimensions that inform a subject-specific computational model. Analysis revealed the need for CT assessment at total lung capacity, rather than functional residual capacity, which was less sensitive to the effects of BT. Final model predictions compared favorably with observed outcomes in terms of airway caliber and asthma control, suggesting that this approach could form the basis of improved clinical practice.NEW & NOTEWORTHY Bronchial thermoplasty is a treatment for asthma that targets the airway smooth muscle directly. We demonstrate the feasibility and constraints of predicting patient-specific response to thermoplasty using a computational model informed by pretreatment CT scans at different lung volumes. Predictions are compared with functional outcomes and posttreatment CT scans. This has the potential to form the basis for improved clinical practice.

Bronchial thermoplasty increases airway volume measured by functional respiratory imaging

BACKGROUND

The purpose of this study was to use CT scanning with computational fluid dynamics to evaluate the mechanisms by which Bronchial Thermoplasty (BT) improves asthmatic symptoms.

METHODS

The study was conducted in a university teaching hospital, experienced in performing BT. Imaging studies were performed before, and after, BT of the left lung, and prior to treatment of the right lung, which therefore acted as a control. On each occasion, two high-resolution CT scans were performed, one at full inspiration (TLC) and the other at Functional Residual Capacity (FRC). The study protocol was offered to 10 patients, all of whom met the definition of severe asthma, despite high dose inhaled corticosteroids and dual long acting bronchodilators.

RESULTS

Significant increases in airway luminal volume were observed on the treated side, compared with control, at both full inspiration (by 27%) and at FRC (by 17%). The ratio of distal airway volume to lung volume significantly increased on the treated side. The change in airway volume with inspiration from FRC increased by 48% on the treated side compared to 5% in the control lung, suggesting treatment increased airway distensibility. No effect was observed on airway wall thickness, nor air trapping. There was a trend towards correlation between the improvement in airway volume at TLC and improvement in symptoms.

CONCLUSION

This study demonstrates that BT increases the luminal airway volume on the treated side compared to the control lung. We suggest that this is an important link between the airway smooth muscle atrophy demonstrated pathologically, and the improvement in symptoms observed clinically.

Effectiveness and response predictors of omalizumab in a severe allergic asthma population with a high prevalence of comorbidities: the Australian Xolair Registry

BACKGROUND

Severe asthma is a high impact disease. Omalizumab targets the allergic inflammatory pathway; however, effectiveness data in a population with significant comorbidities are limited.

AIMS

To describe severe allergic asthma, omalizumab treatment outcomes and predictors of response among the Australian Xolair Registry participants.

METHODS

A web-based post-marketing surveillance registry was established to characterise the use, effectiveness and adverse effects of omalizumab (Xolair) for severe allergic asthma.

RESULTS

Participants (n = 192) (mean age 51 years, 118 female) with severe allergic asthma from 21 clinics in Australia were assessed, and 180 received omalizumab therapy. They had poor asthma control (Asthma Control Questionnaire, ACQ-5, mean score 3.56) and significant quality of life impairment (Asthma-related Quality of Life Questionnaire score 3.57), and 52% were using daily oral corticosteroid (OCS). Overall, 95% had one or more comorbidities (rhinitis 48%, obesity 45%, cardiovascular disease 23%). The omalizumab responder rate, assessed by an improvement of at least 0.5 in ACQ-5, was high at 83%. OCS use was significantly reduced. The response in participants with comorbid obesity and cardiovascular disease was similar to those without these conditions. Baseline ACQ-5 ≥ 2.0 (P = 0.002) and older age (P = 0.05) predicted the magnitude of change in ACQ-5 in response to omalizumab. Drug-related adverse events included anaphylactoid reactions (n = 4), headache (n = 2) and chest pains (n = 1).

CONCLUSION

Australian patients with severe allergic asthma report a high disease burden and have extensive comorbidity. Symptomatic response to omalizumab was high despite significant comorbid disease. Omalizumab is an effective targeted therapy for severe allergic asthma with comorbidity in a real-life setting.

Real-life effectiveness of omalizumab in severe allergic asthma above the recommended dosing range criteria

BACKGROUND

Omalizumab (Xolair) dosing in severe allergic asthma is based on serum IgE and bodyweight. In Australia, patients eligible for omalizumab but exceeding recommended ranges for IgE (30-1500 IU/mL) and bodyweight (30-150 kg) may still receive a ceiling dose of 750 mg/4 weeks. About 62% of patients receiving government-subsidized omalizumab are enrolled in the Australian Xolair Registry (AXR).

OBJECTIVES

To determine whether AXR participants above the recommended dosing ranges benefit from omalizumab and to compare their response to within-range participants.

METHODS

Data were stratified according to dose range status (above-range or within-range). Further sub-analyses were conducted according to the reason for being above the dosing range (IgE only vs. IgE and weight).

RESULTS

Data for 179 participants were analysed. About 55 (31%) were above recommended dosing criteria; other characteristics were similar to within-range participants. Above-range participants had higher baseline IgE [812 (IQR 632, 1747) IU/mL vs. 209 (IQR 134, 306) IU/mL] and received higher doses of omalizumab [750 (IQR 650, 750) mg] compared to within-range participants [450 (IQR, 300, 600) mg]. At 6 months, improvements in Juniper 5-item Asthma Control Questionnaire (ACQ-5, 3.61 down to 2.01 for above-range, 3.47 down to 1.93 for within-range, P < 0.0001 for both) and Asthma Quality of Life Questionnaire (AQLQ mean score (3.22 up to 4.41 for above-range, 3.71 up to 4.88 for within-range, P < 0.0001) were observed in both groups. Forced expiratory volume in one second (FEV₁ ) improved among above-range participants. There was no difference in response between above-range and within-range participants. Above-range participants due to either IgE alone or IgE and weight had similar improvements in ACQ-5, AQLQ and FEV₁ .

CONCLUSIONS AND CLINICAL RELEVANCE

Patients with severe allergic asthma above recommended dosing criteria for omalizumab have significantly improved symptom control, quality of life and lung function to a similar degree to within-range participants, achieved without dose escalation above 750 mg.

'New to Forensic'; implementing a problem-based introductory educational programme for forensic practitioners in Scotland

The New to Forensic educational programme has been developed for use across all forensic services in Scotland. It is designed to meet the needs of all staff who are both new to and already working within forensic mental health services. Its objectives are targeted to both clinical and non-clinical staff. The programme follows the patient's journey through the mental health and criminal justice systems. It covers mental disorder, legislation, psychiatric defences, assessment and treatment, risk of harm to others, services, attitudes and boundaries, multidisciplinary working, users and carers, community, learning disability, and prison services. It is self-directed and practice based, and uses a problem-based approach. Over a 3-year period, trainers and mentors have been trained to deliver the programme by members of the School of Forensic Mental Health http://www.forensicnetwork.scot.nhs.uk/ and all services have adopted the programme as a core educational initiative. Initial findings from the programme evaluation indicate a significant improvement in learning following engagement in the initiative.

Guidelines for the management of hepatitis C in general practice: a semi-qualitative interview survey of GPs’ views regarding content and implementation

BACKGROUND

Hepatitis C is a common infection among people who attend GPs for methadone maintenance treatment.

AIM

To determine the views of GPs towards clinical guidelines for the management of hepatitis C among current or former injecting drug users in advance of their implementation.

METHODS

A purposive sample of 14 GPs (10% of the total prescribing methadone at the time the guidelines were developed) was invited to review a pre-publication draft of the guidelines and interviewed regarding content, presentation, perceived barriers to implementation and suggested interventions to facilitate effective implementation of the guidelines.

RESULTS

GPs indicated the guidelines were useful but suggested aspects of presentation should be clarified. Organisational issues were identified as the principal barriers to effective implementation, with the provision of additional nursing support the principal intervention suggested to facilitate implementation.

CONCLUSIONS

Interviewing intended recipients may be an important step in ensuring clinical practice guidelines are effectively implemented.

Undergraduate medical students' experience in general practice

BACKGROUND

Increasingly, undergraduate medical education is becoming community-based. Logbooks are a useful tool in documenting the range of clinical exposure and learning opportunities available to students during clinical training, particularly where the role of new clinical settings for training medical students is being explored.

AIMS

To describe the clinical experience of medical students during an undergraduate programme in general practice at an Irish University.

METHODS

Medical students in the fifth year of medical school were asked to record data from 20 consecutive consultations during a clinical attachment in general practice.

RESULTS

A total of 186 students (82% of total) recorded data on 3,710 consultations. The patient population encountered was similar in demography and morbidity profile to other general practice populations, with hypertension, preventive immunisation and cough the most frequently encountered diagnostic labels. Respiratory illness and circulatory illness were the most frequently encountered primary and secondary presentations, respectively. An active role was adopted by students in almost half of all consultations.

CONCLUSIONS

This paper provides evidence that general practice in Ireland is a setting in which medical students can both encounter a wide range of clinical problems and engage in active learning processes.

Experience of hepatitis C among current or former heroin users attending general practice

The majority of injecting drug users in Ireland are infected with hepatitis C (HCV) and many attend general practice for methadone maintenance treatment. To describe awareness and experience of HCV infection, related investigations and treatment, a semi-qualitative interview study of current or former heroin users attending a general practice was carried out. Twenty-five patients (69% of total) were interviewed, of whom 23 were on methadone maintenance therapy at the time of the interview and 22 were HCV positive. While awareness of harm reduction measures and health implications of the infection was good, continued high-risk activity was common. Negative experiences at diagnosis, of subsequent investigations and treatments received were common. Only one person had been treated for HCV. We conclude there are a number of barriers to effective HCV management among heroin users and further research is needed to improve our understanding of this issue.

Deaths in general practice: an Irish national profile

BACKGROUND

There is little information on general practitioner (GP) involvement in terminal care. Aim This study explores general practice experience of the care of dying patients.

METHODS

One hundred and forty-two GPs offered to participate in a study of consecutive deaths during three months, to a maximum of five cases per practice. Data were collected on patient characteristics, cause and place of death, terminal care and GP notification of deaths.

RESULTS

One hundred and three GPs (73%) completed data collection. Participating GPs were younger and more likely to be in group practice. There were 297 deaths reported: 34% of practices had five deaths or more but 20% had no death. Seventy-five per cent of patients had one GP consultation in the final three months, 60% had at least one hospital admission and 38.8% of deaths occurred at home. Mean home visit, surgery consultation and phone consultation rates were 5.4, 1.8 and 3.6 respectively. In 88% of cases, the GP was informed of the death within one week.

CONCLUSIONS

GPs are notified rapidly of deaths in all groups and causes. In the majority, the GP has had recent clinical contact and has often been heavily involved in care. Most deaths and care occur outside the cancer-related sphere.

Pulmonary presentations of amyloidosis

Respiratory tract involvement with amyloid is rare. We report eight cases of lower respiratory tract amyloidosis including a case of isolated pulmonary interstitial amyloidosis treated with chemotherapy, two cases of recurrent endobronchial amyloid with airway obstruction successfully treated with laser therapy and three cases of localized nodular pulmonary amyloidosis. The subjects with endobronchial and nodular amyloid demonstrated good long-term survival, while those with systemic or interstitial pulmonary amyloid had progressive disease and poor survival. Circulating monoclonal immunoglobulins were identified in five of the eight cases as the likely cause of the amyloid.

Therapeutic efficacy of granulocyte-macrophage colony-stimulating factor in patients with idiopathic acquired alveolar proteinosis

Alveolar proteinosis (AP) is characterized by excessive surfactant accumulation, and most cases are of unknown etiology. Standard therapy for AP is whole-lung lavage, which may not correct the underlying defect. Because the hematopoietic cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) is required for normal surfactant homeostasis, we evaluated the therapeutic activity of GM-CSF in patients with idiopathic AP. Fourteen patients received 5 microg/kg/d GM-CSF for 6 to 12 wk with serial monitoring of the alveolar-arterial oxygen gradient ([A-a]DO2), diffusing capacity of carbon monoxide, computed tomographic scans, and exercise testing. Patients not responding to 5 microg/kg/d GM-CSF underwent stepwise dose escalation, and responding patients were retreated at disease recurrence. Stored pretreatment sera were assayed for GM-CSF-neutralizing autoantibodies. According to prospective criteria, five of 14 patients responded to 5 microg/kg/d GM- CSF, and one of four patients responded after dose escalation (20 microg/kg/d). The overall response rate was 43% (mean improvement in [A-a]DO2 = 23.2 mm Hg). Responses lasted a median of 39 wk, and were reproducible with retreatment. GM-CSF was well-tolerated, with no late toxicity seen. The only treatment-related factor predictive of response was GM-CSF-induced eosinophilia (p = 0.01). Each of 12 patients tested had GM-CSF-neutralizing autoantibodies present in pretreatment serum. We conclude that GM- CSF has therapeutic activity in idiopathic AP, providing a potential alternative to whole-lung lavage.

A & E services in Ireland: the potential role of general practice in accident and emergency services

BACKGROUND

In 1996, Irish accident and emergency (A&E) departments had approximately 1.2 million visits. General practitioners (GPs) have been shown to work efficiently in A&E.

AIM

This study aimed to describe the current A&E structures in Ireland and the potential contribution of general practice.

METHOD

Questionnaires were sent to all 43 Irish A&E departments seeking information on staffing levels, training posts and interest in the role of GPs within the department.

RESULTS

Thirty-four (79%) hospitals responded, representing at least 71% of all A&E visits. Eleven (32%) had A&E consultants. In 16 (47%) hospitals the A&E department was supervised by other consultants; in 14 supervision was for five hours per week or less. Seven hospitals had no consultant supervision. Twenty-six (76%) had NCHDs assigned to the department. Only 11% of NCHDs were in training in A&E medicine. Six departments employed GPs but 28 said they would like to do so. Most wished GPs to see non-urgent cases but one-third wished them to see all cases. Current staffing levels had little relationship with departmental workload.

CONCLUSIONS

The limited consultant supervision and small numbers of NCHDs in training for A&E medicine raise concerns about staffing. Most hospitals want GPs to work in their A&E departments. This has implications for training and for the interface between general practice and the A & E department.

Experience of heroin overdose among drug users attending general practice

BACKGROUND

Heroin overdose is responsible for significant mortality. It has not previously been highlighted as an important prevention or care issue for general practitioners (GPs) involved in the management of drug misuse.

AIMS

To examine the prevalence and experience of heroin overdose in a population of drug users attending a general practice.

METHOD

A questionnaire-based interview of drug users attending a general practice in Dublin, Ireland.

RESULTS

Twenty-four (73% of estimated total) drug users were interviewed. Although 17 (71%) were on recognised methadone treatment programmes, 10 (42%) were still injecting heroin. A total of 23 (96%) had witnessed an overdose, with 10 (42%) having been victims of overdose themselves. Twenty-two (92%) knew a victim of fatal overdose, with four (17%) having been present at a fatal overdose. The interviews revealed high levels of activity associated with overdose and poor use of preventive measures.

CONCLUSION

The issue of prevention and management of overdose should become a priority for GPs caring for opiate-dependent patients.

Methadone maintenance in general practice: impact on staff attitudes

BACKGROUND

The evaluation of a structured protocol for the discharge of stabilised patients on methadone maintenance to general practice provided an opportunity to evaluate the impact on the attitudes of general practitioners (GPs) and practice staff.

AIM

To assess attitudes, expectations and experience among GPs and practice staff before the introduction of structured methadone maintenance and six months after its introduction.

METHODS

A postal questionnaire was sent to 31 GPs and 23 receptionists in 23 Dublin general practices before the patient's first visit and six months later at the end of the study period. Outcome measures were staff attitudes, incidence of disruption, perceived difficulties in providing care and in prescribing methadone, and stress levels.

RESULTS

There was a generally positive attitude to provision of methadone in general practice for stabilised patients, although it was not anticipated to be problem free. Following six months involvement attitudes were similar; stress levels were unchanged, but fewer GPs anticipated problems in delivering the service. All continued to participate in the scheme.

CONCLUSION

GPs and receptionists in this sample had mixed views about methadone maintenance which were unchanged by six months experience of the service. The study illustrates important issues in the recruitment and support of general practice in meeting this need.

Cardiovascular effects of volatile anesthesia in rabbits: influence of chronic heart failure and enalaprilat treatment

Circulatory responses to isoflurane and halothane anesthesia were studied in eight rabbits with biventricular cardiomyopathy induced by doxorubicin (Adriamycin, 14 mg/kg IV over 7 wk) and in eight controls (saline injections). In preliminary operations pulsed-Doppler flow probes were placed on the ascending aorta, left renal artery, and lower abdominal aorta. Each group was studied after 4, 6, and 7 wk of treatment. The development of congestive heart failure (CHF) was associated with decreases in mean arterial pressure and cardiac output (CO) of 14% and 16%, respectively, (P less than 0.05) and an increase in heart rate. In controls, each anesthetic agent produced dose-related decreases in mean arterial pressure and increases in heart rate, but not significant changes in CO. Renal blood flow was reduced to a similar degree by 1.3 MAC halothane (24% decrease) and 1.3 MAC isoflurane (21% decrease); hindlimb blood flow was reduced only by halothane. As CHF developed there was an attenuation of the heart rate response to anesthesia. Halothane, but not isoflurane, significantly reduced CO in more advanced stages of CHF. The changes in renal blood flow and hindlimb blood flow with each anesthetic in the CHF group were similar to those observed in controls and did not vary with week of treatment. Administration of the angiotensin-converting enzyme inhibitor enalaprilat (0.2 mg/kg IV) reversed the CO and renal blood flow effects of halothane except after 7 wk of treatment in the CHF group, when the combination of halothane and enalaprilat resulted in severe circulatory depression.

Cardiovascular responses to graded treadmill exercise during the development of doxorubicin induced heart failure in rabbits

STUDY OBJECTIVE

The aim was to examine the haemodynamic and humoral responses to graded treadmill exercise, serially during the development of congestive heart failure.

DESIGN

Doxorubicin (1 mg.kg-1) was given to rabbits twice weekly intravenously over 8 weeks to induce a low output congestive cardiomyopathy. Treadmill exercise at 8 and 16 m.min-1 was performed at weeks 0, 2, 4, 6, 7, and 8. During each exercise study, continuous recordings were made of cardiac output, mean arterial pressure, and heart rate, and central venous blood was sampled at rest and during the last 10 s of exercise for plasma noradrenaline and plasma renin activity.

EXPERIMENTAL MATERIAL

Six cross-bred English rabbits, mean weight 2.6 kg, received doxorubicin treatment; three control rabbits received vehicle injection.

MEASUREMENTS AND MAIN RESULTS

Over the first 2 weeks, resting haemodynamic variables and responses to exercise were normal in all rabbits. Thereafter, doxorubicin treated rabbits had progressive falls in resting cardiac index and mean arterial pressure, and rises in resting heart rate and systemic vascular resistance. The normal increases in cardiac index and mean arterial pressure with exercise were progressively attenuated, despite an increase in resting and exercising heart rate. The resting levels of plasma noradrenaline and plasma renin rose after the fourth week of doxorubicin treatment. Throughout the experiment, exercise consistently raised plasma noradrenaline and renin, but the exercising levels of both hormones increased as heart failure progressed. Four of the six doxorubicin treated rabbits became exhausted in the final run and there was an intense rise in systemic vascular resistance.

CONCLUSIONS

In this rabbit model of chronic heart failure, sympathetic vasoconstrictor drive is greater than normal at rest, and is greatly exaggerated during exercise. It is suggested that this abnormal response to exercise results from a combination of failure of arterial pressure to reach the elevated set point of the arterial baroreflex, increased afferent input from exercising muscles due to their underperfusion, and increase in central command due to muscle fatigue.

Teaching the nursing process

Gerard Carton, Dave Langton and David Robinson discuss a pilot study of an innovative approach to the design and implementation of a research-led, clinically-based and clinically-relevant teaching package for individualised care. The difficulties in transferring classroom-taught theory to psychiatric practice are considered. Nursing staff in the context of Rampton Hospital have, for example, experienced problems in applying the principles of the Open University OU P553 Course to the clinical setting.

Vasoconstriction in the renal vascular bed during exercise: studies in control and heart failure rabbits

1. The effects of graded treadmill exercise on renal blood flow (RBF) were examined in seven rabbits, in which congestive heart failure (CHF) was produced by the administration of doxorubicin, 1 mg/kg, twice weekly for 8 weeks, and in seven controls. A third group of five rabbits underwent doxorubicin treatment with the addition of surgical section of the left renal sympathetic nerve. 2. During submaximal exercise, there was a small reduction in RBF in controls, which was greatly exaggerated in CHF. 3. In both control and heart failure rabbits, there was a precipitous fall in RBF as exercise fatigue developed. 4. Renal sympathectomy ablated these changes in RBF during exercise. 5. It is concluded that in heart failure there is an exaggerated, sympathetically mediated, diversion of blood flow away from the kidney. The onset of exercise fatigue in both normal and heart failure rabbits is accompanied by a marked intensification of this process.

Regional distribution of the cardiac output and renal responses to atrial natriuretic peptide infusion in rabbits with congestive heart failure

1. A biventricular, low-output congestive cardiomyopathy was induced in 19 rabbits by administering adriamycin (16 mg/kg). The effects of alpha-rat atrial natriuretic peptide (ANP) infused at 0.1, 0.2 and 0.4 micrograms/kg per min, were then examined in terms of (i) central haemodynamics (ii) regional blood flow (iii) renal function and (iv) plasma norepinephrine and plasma renin. 2. In this dose range, ANP produced progressive and significant falls in stroke volume, cardiac output and mean arterial pressure, owing to a fall in venous return. The heart rate response to this was blunted. 3. Using radiolabelled microspheres, significant falls in the perfusion of cutaneous, gastrointestinal and musculoskeletal tissues were observed, due to reduced vascular conductances in these beds. These changes were accompanied by activation of the sympathetic nervous system as evidenced by a progressive rise in plasma norepinephrine. A significant increase in plasma renin was only observed with the highest infusion of ANP. 4. Renal blood flow was maintained in the face of a falling mean arterial pressure and cardiac output, but diuretic and natriuretic effects were absent. 5. It was concluded that the dominant influence of ANP infusion in this model of heart failure appeared to be a reduction in cardiac preload with detrimental overall haemodynamic consequences.

Comparison of felodipine extended release and conventional tablets in essential hypertension using ambulatory blood pressure monitoring

Two formulations of felodipine, conventional and extended release (ER) tablets, were compared in a double-blind, crossover study of patients whose blood pressure was not being controlled using metoprolol 100 mg once daily. Nineteen patients with a supine diastolic blood pressure greater than or equal to 95 mmHg after 4 weeks of taking metoprolol and placebo were randomly assigned to felodipine conventional (5 mg twice a day) or ER (10 mg once daily) for 4 weeks. A 2-week washout period was then followed by 4 weeks of treatment with the alternative formulation. Metoprolol once daily was taken concomitantly throughout the study. Clinic blood pressure was measured at 0 h (i.e. 12 h after the last dose of conventional, and 24 h after the last ER felodipine dose), and then 2 and 5 h after the following dose had been taken. Ambulatory blood pressure and the heart rate were monitored over 24 h using an Accutracker (Suntech Medical Instruments, Raleigh, North Carolina, USA). During the final treatment, both felodipine formulations caused similar substantial falls in supine blood pressure compared with pressures prior to randomized treatment. The falls in clinic blood pressures (systolic/diastolic) were similar with the conventional and ER formulations at all time points, i.e. 0 h (21/13; 19/11 mmHg), 2 h (39/18; 36/18 mmHg) and 5 h (30/12; 35/11 mmHg) after the morning dose was taken. Both formulations also produced similar falls in blood pressures over 24 h and during the daytime (21/12; 20/12 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)