Biomedical subjects

Jennifer A Alison

Publications and source records attributed to Jennifer A Alison.

9 recordsLinked to original sources

PubMed2006

Study protocol: home-based physical rehabilitation for survivors of a critical illness [ACTRN12605000166673].

INTRODUCTION: Numerous primary studies and several review papers have highlighted delayed physical and psychological recovery for survivors of critical illness, often beyond 6 months after discharge. This randomized controlled trial with blinded assessment aims to test the effects of an 8-week, home-based, individually tailored physical rehabilitation programme on physical and psychological recovery for survivors of a critical illness after discharge from hospital. METHOD: Participants are survivors of a critical illness discharged from nine intensive care units (ICUs) in Australia, who are aged 18 years or older, in an ICU longer than 48 hours, discharged home to self-care or carer (non-institutional care), able to participate in physical rehabilitation, and within the hospitals' local geographical areas for home visits. The study is based in participants' home environments. Blinded assessments at weeks 1, 8 and 26 after hospital discharge examine physical functioning, exercise capacity, health-related quality of life and psychological well being. The intervention is graded, individualized endurance and strength training prescribed by a pulmonary rehabilitation physiotherapist over an 8-week period, with three home visits, five follow-up phone calls, and a printed exercise manual supporting the training. Initial focus is on lower limb exercises and walking, with warm-up stretches, and progresses to the addition of core stabilization and upper limb exercises. RESULTS: The burden of a critical illness is well documented. This novel study will determine whether a home-based physical rehabilitation programme improves the recovery trajectory for survivors of critical illness. The projected sample size of 200 patients aims to detect a clinically important 10% improvement in physical functioning. The study will also examine whether other important physical and psychological measures are improved. CONCLUSION: This multicentre, randomized controlled trial will examine outcomes that are meaningful to patients, their family and society, namely functional ability and well being. The study will also target a health problem that is likely to increase as the population ages. If the programme is effective, it will provide a model that can be easily adapted and adopted by existing primary care or community services to improve the recovery of individuals following critical illness.

Clinical Protocols↗

PubMed2006

Exercise capacity and quadriceps muscle metabolism following training in subjects with COPD.

The aim of the study was to determine whether 16 sessions of exercise training, completed twice weekly, alters exercise capacity, quadriceps muscle metabolism, cross-sectional area (CSA) and strength in subjects with chronic obstructive pulmonary disease (COPD). We studied (a) 10 COPD subjects (mean age+/-sem = 71+/-2 years; FEV1 = 0.99+/-0.1 L) before and after 16 sessions of exercise training, and (b) 10 healthy subjects (age = 68+/-3 years). The COPD subjects underwent an incremental peak exercise test using a cycle ergometer and a 6-min walk test: both improved following exercise training (P < 0.05). Magnetic resonance spectroscopy measurements, in quadriceps muscle, of post-exercise phosphocreatinine (PCr) recovery kinetics were used to assess mitochondrial function in vivo: in the COPD subjects pre-training this was 19+/-8% lower than in healthy subjects (P = 0.03), but a 38+/-12% increase was seen in the COPD subjects following training (P = 0.003). Magnetic resonance imaging was used to assess quadriceps CSA: after training in the COPD subjects this showed a 7+/-2% increase (P = 0.03). Quadriceps strength, measured by the best of five maximum voluntary contractions, also showed a 32+/-11% increase in the COPD subjects (P = 0.007). Sixteen sessions of exercise training, performed twice weekly, increased exercise capacity as well as quadriceps mitochondrial capacity, CSA and strength in the subjects with COPD.

Aged↗

PubMed2006

Manual vibration increases expiratory flow rate via increased intrapleural pressure in healthy adults: an experimental study.

QUESTION: What is the relationship between vibration of the chest wall and the resulting chest wall force, chest wall circumference,intrapleural pressure, and expiratory flow rate? Is the change in intrapleural pressure during vibration the sum of the intrapleural pressure due to recoil of the lung, chest wall compression, and chest wall oscillation? DESIGN: Randomised, within-subject,experimental study. PARTICIPANTS: Seven experienced cardiopulmonary physiotherapists and three healthy adults. INTERVENTION: Vibration (compression + oscillation), compression alone, and oscillation alone were applied manually to the chest walls of healthy participants during passive exertion and compared with passive expiration alone. OUTCOME MEASURES: Chest wall force, chest wall circumference, intrapleural pressure, and expiratory flow rate. RESULTS: During vibration, coherence was high(r2 > 0.97) between external chest wall force, chest wall circumference, intrapleural pressure, and expiratory flow. The mean change in intrapleural pressure during vibration was 9.55 cmH2O (SD 1.66), during chest compression alone was 8.06 cmH2O(SD 1.65), during oscillation alone was 7.93 cmH2O (SD 1.57), and during passive expiration alone was 6.82 cmH2O (SD 1.51). During vibration, compression contributed 13% of the change in intrapleural pressure, oscillation contributed 12%, and lung recoil contributed the remaining 75%. CONCLUSIONS: During vibration the chest behaves as a highly linear system. Changes in intrapleural pressure occurring during vibration appear to be the sum of changes in pressure due to lung recoil and the compressive and oscillatory components of the technique, which suggests that all three components are required to optimise expiratory flow.

Adult↗

PubMed2006

Vibration and its effect on the respiratory system.

Vibration is a manual technique used widely to assist with the removal of pulmonary secretions. Little is known about how vibration is applied or its effect on the respiratory system. The purpose of this study was to describe mechanical consequences of vibration on the chest wall of a normal subject and the effects of vibration on expiratory flow rates and volumes. The effects of vibration were compared to other interventions of chest wall compression, chest wall oscillation, cough, huff from high lung volume, inspiration to total lung capacity with relaxed expiration, tidal breathing, and sham. Sixteen physiotherapists applied vibration and other interventions in a randomised order to the chest wall of a healthy adult female subject. The magnitude and direction of the force and the frequency of vibration were measured by an instrumented bed with seven load cells. Inductive plethsysmography measured the change in chest wall circumference with vibration. A heated pneumotachometer measured inspiratory and expiratory flow rates, which were integrated to provide volumes. Vibration was applied with a mean resultant force of 74.4 N (SD 47.1). The mean (SD) change in chest wall circumference and frequency of vibration were 0.8 cm (SD 0.4) and 5.5 Hz (SD 0.8) respectively. The mean peak expiratory flow rate was 0.97 l/s (SD 0.27). Peak expiratory flow rates with vibration were less than 20% of those achieved with cough or huff from high lung volume but greater than with chest wall compression, chest wall oscillation, relaxed expiration from total lung capacity, sham treatment or tidal breathing.

Adult↗

PubMed2005

Effect of body position on maximal expiratory pressure and flow in adults with cystic fibrosis.

Maximum expiratory pressure (MEP) and peak expiratory flow rate (PEFR) are used as surrogate measures of cough and huff strength. Some body positions (particularly head-down tilt) significantly affect these measures in people with normal respiratory function and with chronic obstructive pulmonary disease. This may have implications for people with cystic fibrosis (CF), who use coughing and huffing and may use gravity-assisted drainage positions for airway clearance. Previous research concluded that body position does not affect MEP in people with CF, although head-down tilt was not examined and PEFR was not measured. This study investigated the effect of body position on MEP and PEFR in 20 adults with stable CF. Repeated measures of MEP and PEFR were performed across seven positions (standing, chair-sitting, sitting in bed with backrest vertical, sitting in bed with backrest at 45 degrees , supine, side-lying, and side-lying with head-down tilt 20 degrees ) in random order. During testing, reflux sensation and oxygenation were monitored. MEP was significantly reduced in side-lying and in the head-down tilt position. PEFRs were significantly reduced in the three-quarters sitting, supine, side-lying, and head-down positions. Oxygenation and reflux scores were worst in the head-down position. Despite statistical significance, the differences observed between positions in this stable population were of small magnitude. The effect of body position on MEP and PEFR may be more relevant during airway clearance treatments of the acutely unwell person with CF.

Adolescent↗

PubMed2004

Physiological responses to the early mobilisation of the intubated, ventilated abdominal surgery patient.

The aim of this study was to investigate the effects of mobilisation on respiratory and haemodynamic variables in the intubated, ventilated abdominal surgical patient. Mobilisation was defined as the progression of activity from supine, to sitting over the edge of the bed, standing, walking on the spot for one minute, sitting out of bed initially, and sitting out of bed for 20 minutes. Seventeen patients with age (mean +/- SD) 71.4 +/- 7.1 years satisfied inclusion criteria. Respiratory and haemodynamic parameters were measured in each of the above positions and compared with supine. In the 15 subjects who completed the protocol, standing resulted in significant increases in minute ventilation (VE) from 15.1 +/- 3.1 l/min in supine to 21.3 +/- 3.6 l/min in standing (p < 0.001). The increase in VE in standing was achieved by significant increases in tidal volume (VT) from 712.7 +/- 172.8 ml to 883.4 +/- 196.3 ml (p = 0.008) and in respiratory rate (fR) from 21.4 +/- 5.0 breaths/min to 24.9 +/- 4.5 breaths/min (p = 0.03). No further increases were observed in these parameters beyond standing when activity was progressed to walking on the spot for one minute. When supine values were compared with walking on the spot for one minute, inspiratory flow rates (VT/TI) increased significantly from 683 +/- 131.8 ml/sec to 985.1 +/- 162.3 ml/sec (p = 0.001) with significant increases in rib cage displacement (p = 0.001) and no significant increase in abdominal displacement (p = 0.23). Arterial blood gases displayed no improvements following mobilisation. Changes in VT, fR, and VE were largely due to positional changes when moving from supine to standing.

Abdomen↗

PubMed2003

Arm positioning alters lung volumes in subjects with COPD and healthy subjects.

Subjects with chronic obstructive pulmonary disease (COPD) have difficulty performing arm exercise, particularly if the arms are unsupported and elevated. The purpose of this study was to evaluate the effect of arm position on static lung volumes in COPD and healthy subjects. Lung volumes were measured by plethysmography in nine COPD subjects (mean age +/- SD = 67.3 +/- 10.3 years; % pred FEV1 +/- SD = 39.7 +/- 10.9%) and nine healthy subjects (mean age +/- SD = 55.8 +/- 8.8 years; % pred FEV1 +/- SD = 102.9 +/- 12.2%) with the arms below 90 degrees shoulder flexion, at 90 degrees shoulder flexion and above 90 degrees shoulder flexion. In all subjects a significant increase in functional residual capacity (FRC) and reduction in inspiratory capacity (IC) was shown with arms above 90 degrees shoulder flexion when compared with both arms below 90 degrees shoulder flexion (mean increase in FRC (95% CI) was 0.17 L (0.06 to 0.27) for COPD and 0.29 L (0.11 to 0.47) for healthy subjects; mean reduction in IC (95% CI) was 0.24 L (0.1 to 0.38) for COPD and 0.45 L (0.22 to 0.68) for healthy subjects) and arms at 90 degrees shoulder flexion (mean increase in FRC (95% CI) was 0.15 L (0.01 to 0.29) for COPD and 0.22 L (0.11 to 0.34) for healthy subjects; mean reduction in IC (95% CI) was 0.14 L (0.01 to 0.26) for COPD and was 0.29 L (0.17 to 0.42) for healthy subjects). These changes may alter lung mechanics and, in COPD subjects, may affect their ability to perform arm exercise above shoulder height

Adult↗

PubMed2003

A randomized controlled trial of the effects of intensive sit-to-stand training after recent traumatic brain injury on sit-to-stand performance.

OBJECTIVE: To examine the effectiveness of intensive practice of sit-to-stand on motor performance, exercise capacity and exercise efficiency in traumatic brain-injured patients during early inpatient rehabilitation. DESIGN: Single-blind randomized controlled pilot study. SETTING: Brain injury rehabilitation unit. SUBJECTS: Twenty-four subjects who had recently sustained a severe traumatic brain injury (TBI) were randomized into an experimental (n = 13) and a control (n = 11) group. INTERVENTIONS: In addition to their usual rehabilitation programme, subjects in the experimental group participated in four weeks of intensive training of sit-to-stand and step-up exercises with the aim of improving performance of sit-to-stand. The control group did no additional sit-to-stand or step-up training. MAIN OUTCOME MEASURES: Total number of sit-to-stands in 3 min as a measure of motor performance; peak oxygen consumption during a maximal 3-min sit-to-stand test (Vo2peak) as a measure of exercise capacity; oxygen consumption during a 3-min equivalent workload sit-to-stand test (Vo2equiv) as a measure of exercise efficiency. Pre- and post-training measurements were made. RESULTS: The exercise programme resulted in a 62% improvement in motor performance (number of repetitions of sit-to-stand in 3 min) for the experimental group compared with the control group's 18% improvement (p < 0.05). There was no significant difference between groups for changes in exercise capacity or efficiency. In the experimental group, the increase in Vo2peak from pre-test to post-test correlated with the increase in sit-to-stand repetitions (p < 0.05). CONCLUSIONS: Intensive task-specific training is recommended as an important component of rehabilitation early following severe traumatic brain injury.

Adolescent↗

PubMedDate not supplied

Arm exercise capacity and dyspnea ratings in subjects with chronic obstructive pulmonary disease.

PURPOSE: This study aimed to compare the metabolic, ventilatory, and dyspnea responses to unsupported arm exercise, supported arm exercise and leg exercise between subjects with chronic obstructive pulmonary disease (COPD) and healthy age-matched controls. METHODS: For this study, 21 subjects with COPD (mean age, 62 +/- 2 years; predicted forced expiratory volume in 1 second [FEV(1)], 37 +/- 3%) and 7 healthy age-matched control subjects (% pred FEV(1) = 109 +/- 5%) were included in the analyses of three incremental exercise tests to peak work capacity: unsupported arm exercise, supported arm exercise (arm ergometry), and leg exercise (cycle ergometry). Work level, oxygen consumption (VO(2)), minute ventilation (V(E)), dyspnea, and rate of perceived exertion were measured each minute. RESULTS: Peak work level and peak VO(2) were significantly reduced in the subjects with COPD for all exercise tests (P <.01 for all), as compared with the control subjects. Within the COPD group, the VO(2) and V(E) at peak exercise were significantly lower for unsupported arm exercise than for both the leg and supported arm exercises (both P <.001). The ratio of V(E) to maximal voluntary ventilation was high for leg exercise (96%), supported arm exercise (91%), and unsupported arm exercise (77%) among the subjects with COPD. At a given percentage of VO(2) peak, dyspnea scores were similar for all the exercise tests. CONCLUSIONS: Ventilatory constraints limit exercise performance in COPD. The lowest amount of work, in terms of VO(2,), was during unsupported arm exercise. Because the subjects with COPD had scores showing similar levels of dyspnea at the same percentage of VO(2) peak, it is suggested that patients be encouraged to reach equivalent dyspnea levels when performing unsupported and supported arm exercise training and leg training.

Arm↗