Phase 1 Inpatient Cardiac Rehabilitation: MET Progression, Sternal Safety, and Discharge Readiness
In short
Phase 1 inpatient cardiac rehabilitation safely advances patients from 1.5 METs to 3.5 METs over 4 to 5 post-operative days, preventing post-CABG thromboembolism.
In this guide (4 sections)
Objectives and Physiological Milestones of Phase 1 Inpatient Rehab
Phase 1 Inpatient Cardiac Rehabilitation begins in the intensive care and step-down surgical units within 24 to 48 hours following Coronary Artery Bypass Grafting (CABG), Percutaneous Coronary Intervention (PCI), or acute myocardial infarction. The primary clinical objectives are counteracting bed-rest deconditioning, preventing Deep Vein Thrombosis (DVT) and atelectasis, reassuring the patient, and safely preparing them for hospital discharge.
Exercise dosing in Phase 1 relies strictly on the Metabolic Equivalent of Task (MET) framework, where 1 MET represents resting baseline oxygen consumption (3.5 mL O2/kg/min). Patients systematically progress from bed-level activities (1.0 to 1.5 METs) to self-care and independent hallway ambulation (3.0 to 3.5 METs).
Stepwise MET Progression Protocol: Post-CABG Hospital Stay
| Post-Op Day / Step | Target MET Level | Functional Activities Permitted | Heart Rate & Hemodynamic Limits | |
|---|---|---|---|---|
| Step 1: Post-Op Day 1 | 1.0 to 1.5 METs | Active-assisted bed exercises, dangle at edge of bed 15 mins | HR < resting + 20 bpm; SBP change < 20 mmHg | |
| Step 2: Post-Op Day 2 | 1.5 to 2.0 METs | Sit in bedside cardiac chair 30 mins, bedside commode, seated grooming | RPE <= 11 on Borg 6-20 scale; SpO2 >= 92% | |
| Step 3: Post-Op Day 3 | 2.0 to 2.5 METs | Room ambulation, hallway walk 50 to 100 feet with assistance | Continuous telemetry monitoring; check for new atrial fibrillation | |
| Step 4: Post-Op Day 4 | 2.5 to 3.0 METs | Independent hallway walk 200 to 500 feet twice daily, standing shower | Monitor surgical leg incision / saphenous graft harvest site edema | |
| Step 5: Post-Op Day 5 (Discharge) | 3.0 to 3.5 METs | Stair flight ascent/descent test (1 flight), home exercise instruction | Prepares patient for safe return home and Phase 2 outpatient referral |
Physiological Exercise Termination Criteria and Safety Red Flags
- Hemodynamic Termination Red Flags: Immediately terminate exercise if systolic blood pressure drops by > 10-15 mmHg below baseline during exertion, resting SBP exceeds 200 mmHg, or diastolic blood pressure exceeds 110 mmHg.
- Electrocardiographic Rhythm Warning Signs: Halt session if telemetry displays new-onset atrial fibrillation, ventricular tachycardia, second- or third-degree heart block, or ST-segment depression / elevation > 1 mm.
- Subjective Symptom Thresholds: Stop activity immediately if the patient reports angina pectoris (chest heaviness radiating to jaw or left arm), excessive dyspnea (Borg CR10 > 5), lightheadedness, pallor, or cold diaphoresis.
Frequently Asked Questions
How soon do you start walking after heart bypass surgery?
Walking begins remarkably early. Most patients sit on the edge of the bed the very next day after surgery, and begin walking short distances down the hospital corridor by day two or three with a physiotherapist.
What is a MET level in cardiac rehabilitation?
MET stands for Metabolic Equivalent of Task. 1 MET is the energy you burn sitting quietly in a chair. Walking slowly down the hall burns about 2 to 3 METs. Therapists use METs to ensure you do not push your healing heart too hard.
Why do therapists test climbing stairs before you leave the hospital?
Before going home, a physiotherapist watches you climb one flight of stairs to make sure your heart rate, blood pressure, and oxygen levels stay safe. This gives you confidence that you can manage stairs at home safely.
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