What are the effects of different types of positive expiratory pressure (PEP) breathing exercises when compared to conventional breathing exercises in patients undergoing coronary artery bypass graft (CABG) surgery?

Study setting: National Hospital Sri Lanka (NHSL)

All patients who admit for CABG surgery in Cardiothoracic Units of NHSL will be consecutively screened for eligibility. Following recruitment, participants will be assigned in to 03 (three) groups (group A, B and C) randomly using sealed envelopes containing the group number. All the patients will be allocated in the study until sample size (180) obtained.

Intervention: Participants in groups A and B will attend sessions of positive expiratory pressure (PEP) exercises by the principal investigator starting from 2 days before surgery. The exercises will be demonstrated and supervised individually by the principal investigator from pre-operative day 2 until discharge from the ward.

Participants of Group C will receive standard management only. All the three groups will continue routine physiotherapy techniques conducted by the ward physiotherapists.

Group A: Commercialized PEP device group (used to create an expiratory resistance of +10 cm of H2O). The patients will be instructed to perform the exercises in the sitting position. Subjects will be instructed to perform slow maximal inspirations, while expiration will be through the device. The exercise session will include 3 sets of 10 deep breaths with 30 to 60 seconds pause between each set per hour while awake.

Group B: PEP – Blow bottle device group. A bottle with 10 cm of water and a 42cm plastic tube (1 cm diameter) will be used as the blow bottle. The maneuver gives will provide a resisted exhalation with an expiratory peak pressure of 10cm H2O. Subjects will be instructed to perform slow maximal inspirations, while expiration through the device, in the sitting position. The exercise included 3 sets of 10 deep breaths with 30 to 60 seconds pause between each set per hour while awake.

Group C: Conventional group Participants will be encouraged to continue routine physiotherapy techniques conducted by the ward staff. They will not be taught any extra breathing exercises.

The routine protocol consists of deep breathing exercises, breathing exercises using an incentive volumetric spirometer associated, coughing and huffing techniques. All participants will be encouraged to continue these exercises hourly while awake.

The exercise programme will be monitored through direct observation twice a day by the principal investigator and by the patient training diary maintained hourly while awake during the hospital. The participants will take the personal device to home after discharge from hospital for home breathing exercises. All the participants (all three groups) will be requested to continue the exercises for one month after surgery at home which will be encouraged through two phone calls weekly and will be monitored with exercise diaries.

Male and female patients between 40 to 70 years of age awaiting CABG surgery at NHSL

Exclusion criteria at point of recruitment
1. Other cardiovascular surgical procedure other than CABG Had a myocardial infarction within the past five days
2. Unstable angina
3. Patients with previous open heart surgery
4. Patients with hemodynamic instability –Blood pressure (BP) less than 110-70 mmHg, Heart rate 100-60, sinus rhythm
5. Uncooperative patients
6. Inability to consent or understand
7. Cognitive impairment
8. Diagnosed with cerebrovascular, orthopedic, neurologic, or cognitive-emotive disorders that would prevent the completion of the pre-surgical test items
9. Patients with COPD and any respiratory conditions
10. Any contraindication to use of PEP therapy e.g. severe haemoptysis, pneumothorax

Exclusion criteria at point of analysis
11. ICU time > 72 hours
12. Depend on mechanical ventilator for more than 24 hours
13. Need balloon pump more than 24 hours
14. Need ionotropic support more than 3 days