1. Clinical Significance
Effects of Physical Training on Functional Status in Patients with Prolonged Mechanical Ventilation
Chiang LL, Wang LY, Wu CP, Wu HD, Wu YT. Effects of physical training on functional status in patients with prolonged mechanical ventilation. Physical Therapy. 2006; 86:
Results Continued
The ventilator-free time increased an average of 8.9 hours (P.01) in the treatment group and 4.8 hours (P.1) in the control group after 6 weeks.
After 3 and 6 weeks of physical training, all functional scores were significantly greater in the treatment group than in the control group except executive functioning (which was significant only after 6 weeks).
At the sixth week of intervention, the average distance walked during the 2-minute walk test was m (n9) for the treatment group.
Changes in BI scores correlated significantly with changes in both respiratory and limb muscle strength and ventilator-free time.
Changes in ventilator free time and the strength of the shoulder and elbow flexors and knee extensors after 6 weeks of physical training correlated significantly with items related to ADL, except for eating and toileting.
Changes in executive functioning scores and FIM total score correlated significantly with changes in limb muscle strength and ventilator-free time.
Abstract
Background and Purpose
The effects of 6 weeks of physical training on the strength of respiratory and limb muscles, on ventilator-free time, and on functional status in patients requiring PMV were examined.
Subjects
39 patients with PMV were initially enrolled in the study and were assigned to either a treatment group (n20) or a control group (n19).
Methods
Subjects in the treatment group received physical training 5 days a week for 6 weeks.
Strength of respiratory and limb muscles, ventilator-free time, and functional status, which was measured by the Barthel Index of Activities of Daily Living (BI) and Functional Independence Measure (FIM), were examined at baseline and at the third and sixth weeks of the study period.
Results
Respiratory and limb muscle strength improved significantly at the third and sixth weeks in the treatment group compared with baseline measurements.
Total BI and FIM scores increased significantly in the treatment group and remained unchanged in the control group.
Discussion and Conclusion
The results show that a 6-week physical training program may improve limb muscle strength and ventilator-free time and thus improve functional outcomes in patients requiring PMV.
Introduction
Patients requiring PMV often have weakness of the respiratory and limb muscles that impairs functional status and health-related quality of life due to adverse effects of medications, and prolonged immobilization.
Purpose
The purpose was to examine the effects of 6 weeks of physical training on the strength of respiratory and limb muscles, ventilator-free time, and on functional status in patients requiring PMV.
Methods
Subjects
39 patients were initially enrolled in the study and assigned to either a treatment group (n20, age = y) or a control group (n19, age = y).
Physical Training
Treatment group performed physical training 5 times per week for 6 weeks.
Subjects performed UE exercises and LE exercises against gravity for 2 sets of 10 repetitions of each motion.
Bedside functional retraining and ambulation were also performed.
Diaphragmatic breathing exercises were assisted and practiced in the supine, semi-Fowler (sitting at a 45° angle) and sitting positions.
Measurements
Respiratory muscle strength was assessed by measuring maximum pressures.
Maximum inspiratory pressure (Pimax) was measured at residual volume, whereas maximum expiratory pressure (Pemax) was measured at total lung capacity.
Strength tested 3 times of shoulder and elbow flexors and knee extensors.
Two instruments were used to assess the subjects’ functional status, which were the BI and FIM.
Limb and respiratory muscle strength were measured and the BI and FIM were administered at baseline, the third and sixth weeks of the study.
If a subject could ambulate without ventilator for at least 1 hour, a 2-minute walk test was performed at comfortable speed with vital signs and SpO2 closely monitored.
Results
The limb strength increased significantly in the treatment group (P.001) at the third and sixth weeks compared with baseline.
At the third and sixth weeks of the study period, Pimax and Pemax increased significantly (P.01) in the treatment group and decreased significantly (P.001) in the control group compared with baseline.
Discussion
The results show that a 6-week physical training program may improve functional status in patients requiring PMV by improving limb muscle strength and ventilator-free time.
After 6 weeks of physical training, 53% of the subjects in the treatment group regained ability to ambulate.
Results suggest that physical training could indeed reverse and prevent the effects of immobilization.
BI and FIM scores could identify outcome changes with physical training in patients requiring PMV, however, whether these changes were “clinically significant” remains a concern.
After a 6-week training program, cognitive domain score increased significantly in the treatment group but deteriorated significantly in the control group.
PMV has a greater effect on physical function than on cognitive function.
A limitation in the study was that a wide variety of patients with different diagnoses required assistance with PMV.
Future research should include larger sample sizes, randomized study design, potential effects of physical training for different patient populations, the ideal duration of physical training and how long the effects last.
Conclusion
Improvements in muscle strength and ventilator-free time after 6 weeks of physical training in patients requiring PMV may enhance their functional status, including both physical and cognitive dimensions.
Clinical Significance
Physical training in patients with PMV is important to increase limb strength, respiratory strength, ventilator-free time and functional outcomes in both physical and cognitive dimensions.
To help patients requiring PMV to improve and regain their ambulation ability.
To help patients that require PMV to exercise and prevent or avoid the effects of immobilization.
Exercise Intervention in the Critical Care Unit – What is the Evidence?
Thomas A. Exercise intervention in the critical care unit –what is the evidence? Physical Therapy Reviews. 2009; 14:50-59.
This systematic literature review supports the article written by Chiang et al. because it provides convincing evidence that decreases in muscle strength occur in critically ill patients who do not receive muscle strengthening exercises.
The relationship between muscle strength, functional scales and other measures of outcome including number of days to wean from mechanical ventilation and length of stay need to be explored.
Feasibility of Physical and Occupational Therapy Beginning from Initiation of Mechanical Ventilation
Pohlman M, Schweickert W, Pohlman A et al. Feasibility of physical and occupational therapy beginning from initiation of mechanical ventilation. Critical Care Medicine. 2010; 38:2089–2094.
This randomized controlled trial supports the article written by Chiang et al. because it discusses that early physical and occupational therapy show improvement in functional and neurocognitive outcomes and shorten duration of ventilation.
Patients in this study were able to accomplish sitting up at bedside, standing, transfers, activities of daily living, and walking during ventilation.
Summary
These three studies are clinically relevant to be aware of the benefits of physical training in individuals requiring PMV.
The article written by Chiang et al. discusses that increase in limb and respiratory strength, functional status and ventilator-free time had increased significantly due to physical training. The article explains that physical training can also reverse and prevent the effects of immobilization.
The article written by Pohlman et al. discusses that physical and occupational therapy had increased functional and decreased mechanical ventilation duration time in these patients.
The article written by Thomas discusses that decreases in muscle strength occur in critically ill patients who do not receive muscle strengthening exercises.
Mary Glorighian
Bellarmine University
PT Student