This study sample included difficult and prolonged weaning patients who fail one weaning attempt of spontaneous breathing trial and who were conscious and able to join the training program. Please note, the instrumentation images are available in the Supplemental Files section.
Fifty general surgery patients who were difficult and prolonged weaning patients from both sexes (men & women) with age ranged from 40 to 50 years old in surgical intensive care unit, Kasr Al Ainy Teaching Hospital, Cairo University and Beni- Suef Teaching Hospital , Beni –Suef University.
These patients were divided randomly into two groups; group A (study group): Twenty five patients who received comprehensive rehabilitation program consist of upper-extremity exercises, lower extremity exercises, pedaling exercises, trunk control exercises and bedside functional training combined with inspiratory muscle training.
-Group B (Control group): Twenty five patients who received traditional chest physical therapy (positioning – modified postural drainage - percussion – vibration) combined with inspiratory muscle training.
A randomization process was performed using closed envelopes. The investigator prepared 50 closed envelopes, each envelope containing a card labeled either group A or group B. Each patient was asked to draw a closed envelope to determine whether he was allocated to group A or group B. The randomization (active dynamic adaptive randomization; minimization) was performed by a colleague who was independent and blind with respect to the study, using closed envelopes with the group description randomly placed within them.
The inclusion criteria was; the general surgery patients who fail one weaning attempt of spontaneous breathing trial ;adequate gas exchange ( paO2 more than 60 mmHg , FiO2 of 0.50 or less) conscious patients receiving assist control or SIMV of equal to or less than 6 b /min or pressure support via trachestomy with SIMV of equal to or less than 6 b /min, pressure support of equal to or less than 15 cmH2O and PEEP of equal to or less than 10 cmH2O;no excessive secretions requiring suctions more than once every hour ; hemodynamically stable patients (lack of hypotension or a need for only low-dose pressors) ; The patients with Acute Physiology and Chronic Health Evaluation II (APACHE II) scale 20 or less.
Exclusion criteria was; patients with persistent altered sensorium ; patients with major cardiac arrhythmia ; patients with comorbid medical conditions (e.g., neurological diseases) or who are under any sedative or paralytic agents that would interfere with strength measurements and limb exercises ;patients with history of underlying neuromuscular disease or acquired polyneuromyopathies ;patients who are unable to perform physical training due to preexisting joint dysfunction ;obese patients
A- Evaluation tools and equipments
1. The APACHE II (Acute Physiology and Chronic Health Evaluation II)
The Apache-II Score provides an estimate of ICU mortality based on a number of laboratory values and patient signs taking both acute and chronic disease into account . It was measured by a colleague who was independent and blind with respect to the study.
2. Mechanical ventilator
The maximal inspiratory pressure was measured by mechanical ventilator by a colleague who was independent and blind with respect to the study .
3. Functional Independence Measure (FIM)
The Functional Independence Measure (FIM) is an outcome measure of the severity of disability for an inpatient rehabilitation setting. It rates 18 activities of daily living on a 7- point scale ranging from fully dependent (1) to independent with no aids (7). In this study only 5 activities were measured by a colleague who was independent and blind with respect to the study, which were bathing, dressing, moving from bed
4. Hand-held dynamometer
A hand-held dynamometer (Lafayette manual muscle test system Model 01163, White Plains, New York, 10602) is a portable device that can be used to obtain more discrete, objective measures of strength during manual muscle testing (MMT) than can be achieved via traditional manual muscle testing. It was measured by a colleague who was independent and blind with respect to the study
B) Training equipments
1. Pedaling Exerciser
A rehabilitation device (UNI-FORCE RPM26001, Profit Country Enterprises Ltd, Kowloon, Hong Kong) that allows application of various loads for both leg (pedaling) and arm (cranking).
Weights from 100 grams to 600 grams were used to progressively increase resistance.
3. Inspiratory muscle trainer
The patient inhaled through a device (RES-HS553-010) with an adjustable, spring-loaded, threshold poppet valve and the patient must generate an inspiratory pressure greater than the indicated threshold pressure setting to compress the spring and open the poppet valve, and the inspiratory pressure must be maintained above the threshold pressure to keep the poppet valve open.
4. Mechanical vibrator
The mechanical vibrator (Thrive, Model 707A, Daito electric machine industry Co., LTD, Japan) was applied to patient chest during expiration to assist airway clearance.
The patient was evaluated at the beginning of the study and at weaning from mechanical ventilation by a colleague who was independent and blind with respect to the study; using the following :
1-Maximal inspiratory pressure
It was conducted after endotracheal or trachestomy aspiration. Maximal inspiratory pressure was performed three times with two minutes rest in between manoeuvers . The highest value of the one second plateau pressure generated on one of the manoeuvers was considered for analysis. The mechanical ventilator was used to measure the plateau pressure (maximal inspiratory pressure). Plateau pressure was measured using the inspiratory hold function on the venilator while the patient was sedated and on volume control mode .
The plateau pressure was measured by ventilator in millibar then it converted to cm H2O by multiplying it by 1.01971621298 (1millibar equals 1.01971621298 cm H2O and near the figure to the nearest two decimal places.
2- Upper and lower extremity muscle strength
Upper and lower extremity muscle strength were assessed using a handheld dynamometer. The shoulder flexor, elbow flexor, and knee extensor muscle groups were included in the measurements. Standard test positions was modified because all patients in this study were using mechanical ventilator and unable to sit up at initial examination. The shoulder and elbow flexors were tested in the semi-Fowler position. The isometric force of the shoulder flexors was tested with the shoulder flexed 90 degrees and the elbow in extended position. The dynamometer was placed just proximal to the epicondyles of the humerus, and the patients were stabilized at the axillary region. The isometric force of the elbow flexors was tested with the elbow flexed 90 degrees, the forearm supinated, and the shoulder in neutral position; the dynamometer was placed just proximal to styloid processes of ulna and radius, and the patients were stabilized at the superior aspect of the arm. All patients in the study were receiving mechanical ventilation through artificial airway; therefore, the recommended test position (i.e., prone position) for the knee extensors was modified to the supine position, with the knee slightly flexed at 20 to 50 degrees, a roller behind the knee, the ankle not touching the bed, and the hands resting on the lap. The dynamometer was placed just proximal to the malleoli of the tibia and fibula. The dynamometer shaft was held perpendicular to the tested limb segment, and the tester applying all manual stabilization. All measurements were performed 3 times using isometric "make" tests. The patients were asked to increase force to a maximum effort over a 2-second period, maintain the maximum effort for approximately 5 seconds, and then stop. This procedure had been shown to yield reliable measurements and to be adequate for measuring maximum isometric strength. The peak force in kilogram of 3 tests was recorded. Two minutes of rest was allowed between repeated readings .
3- The Functional Independence Measure (FIM)
Five activities with the Functional Independence Measure (FIM) were measured, which were bathing, dressing, moving from bed to chair, bowel management, and bladder management.
- Study group treatment procedure
1-Spontaneous breathing trials
Spontaneous breathing trials was used when underlying cause of acute respiratory failure stabilizes or significantly improved and daily assessment of the patient’s readiness for ventilator discontinuation was considered. The spontaneous breathing trial lasted from 30 minutes to 120 minutes combined with CPAP and if the trial had failed, the patient was returned back to full ventilatory support for at least 24 hours before performing a new trial .
The following guidelines were used when determining weaning readiness; resolution of the disease for which the patient was intubated ; paO2/FiO2 of 150-200 requiring PEEP of equal to or less than 5-8cmH2O and FiO2 of equal to or less than 0.4 -0.5 ; haemodynamic stability ; absence of fever ; stable blood pressure ; no or minimal vasopressor ; adequate hemoglobin ; adequate mentation ; adequate cough .
2-Inspiratory muscle training
A threshold inspiratory muscle trainer was connected to the artificial airway with 15 mm and 22 mm adaptors and the patient exhaled through the training device via a low-resistance, one-way, spring-loaded valve through the inhalation orifice. Training bouts consisted of three to five sets of six repetitions breathing through the trainer. Inspiratory muscle strength training sessions was conducted in the morning, 5 to 7 days per week and supplemental oxygen was added as needed during training. Training was conducted with the patient in bed with an approximately 30° head-up tilt and with intensity about 40 %- 50 % of maximal inspiratory pressure. Patients were instructed to maximally exhale before taking a breath and to try to maximally fill the lungs fully with each inspiration. This training breath was repeated six times in each training set. Patients were returned to mechanical ventilation for rest between training sets as needed. Three to five sets of six training breaths were completed for a total of 18 to 30 training breaths per session. Following each training set, the patient indicated a rating of perceived inspiratory exertion on modified Borg scale of 0 to 10, with 0 representing no inspiratory effort and 10 equaling a maximal inspiratory effort. The training threshold pressure setting was adjusted to an exertion rating of 6 to 8. If an exertion rating fell below 6, the pressure was increased, and if the exertion rating exceeded 8, the pressure was reduced. Patients were observed during training for cardiac arrhythmias, for pulse oximetric saturation decreases of more than 5% from baseline, for significant changes in BP, and for subjective evidence of distress. A signal was used by the patient to indicate that he want to stop training before competing six repetitions and return to mechanical ventilation. The complete inspiratory muscle strength training session was about10 min per day  .
3- Upper extremity exercises
Upper-extremity exercises included range of motion (ROM) exercises for the wrist; elbow and shoulder flexion and extension; and shoulder abduction, adduction, and internal and external rotation, with 10 repetitions of each motion per set for 2 sets. Patients initially performed these exercises against gravity in a supine position and progressed to a sitting position as tolerated. These exercises’ resistance then increased to repetitions against resistance using weights (100-600 g)
4-Lower extremity exercises
Lower extremity exercises included ROM exercises for ankle dorsiflexion and plantar flexion, hip and knee flexion and extension, and straight leg raising, with 10 repetitions of each motion per set for 2 sets in the supine position.
The patients were instructed to pedal by lower limb and arm cranking and to maintain at least 30 revolutions per minute. The training intensity and duration was progressively increased depending on the patient’s ability (up to an arbitrary limit of 30 min 2 sessions /day) .
6-Trunk control exercises
The patients received exercises consisting of task-specific movements of the upper and lower part of the trunk both in the supine and sitting positions. The supine exercises involved the pelvic bridge, the unilateral bridge, the flexion rotation of the upper and lower trunk. Sitting exercises included selective flexion extension of the lower trunk; lateral flexion of the upper and lower trunk; rotation of the upper and the lower trunk; weight shifts; forward and lateral reach, with 10 repetitions of each motion per set for 2 sets. The trunk exercises were initiated with moderate assistance and progressed to a state of no assistance. The number of repetitions and intensity of the exercise was determined according to the patient’s performance with adequate rest periods in between.
The intensity of the exercises was increased by introducing one or several of the following changes; reducing the base of support ;increasing the lever arm ; advancing the balance limits ; Increasing the hold time
7-Bedside functional retraining
Bedside functional retraining included turning from side to side on the bed; transfers to and from the bed, chair, and wheelchair; and coming to a standing position. Ambulation was begun as early as patients can tolerate it. Patients were allowed to rest between training sets, and decreased pulse oxygen saturation (SPO2) and any sign or symptom that indicate intolerance was closely monitored throughout the training session. Control group treatment procedure included inspiratory muscle training , manual percussion , mechanical vibration to increase mucociliary clearance , positioning and modified postural drainage such as high side lying or side lying.
Days to wean and success of weaning from mechanical ventilator were evaluated at weaning period
Maximal inspiratory pressure , peripheral muscle strength and Functional independence measure questionnaire were measured at the beginning of the study and at weaning from mechanical ventilator.
Statistical analysis and sample size calculation
All these data were analyzed statistically by using:
1-Descriptive statistics (mean - standard deviation-median).
2- Inferential statistics using paired and unpaired t-test.
The level of significance was (P< 0.05).
3-Non-parametric statistical test for functional independence measure questionnaire (FIM). Mann-Whitney test between groups and Wilcoxon signed-rank test inside each group.
Sample size calculation was performed at the beginning of the study using G_Power statistical software (version 126.96.36.199; Franz Faul, Universit€at Kiel, Germany) (Faul et al., 2009) and this revealed that the appropriate sample size for this study was N= 40 which gave an observed power equal to 0.87. Calculations were performed using alpha= 0. 05, ß =0.2 and an effect size of 0.6.