Day Two After Triple CABG: Lobar Collapse, Sternal Pain and a Sudden Desaturation
A 58-year-old man is referred on day 2 after elective three-vessel coronary artery bypass grafting through a median sternotomy at a MOH cardiothoracic centre. He was extubated eight hours ago. He has a left pleural chest drain, temporary epicardial pacing wires and a central line. Observations: respiratory rate 24, SpO2 93% on 4 L/min nasal cannula, heart rate 104 in sinus rhythm, blood pressure 118/72 mmHg, temperature 37.6 °C. He is using morphine patient-controlled analgesia and has type 2 diabetes. Breath sounds are absent over the left lower zone and the chest radiograph shows left lower lobe atelectasis. Sternotomy pain is 7/10 on coughing; he splints his chest and refuses to cough. He is anxious and says walking is impossible. His wife asks whether he should be resting completely.
1. What are your priorities for the first session, and in what order would you deliver them? Justify the sequence.
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Priority: reverse the atelectasis and control pain - ambulation comes after, not first.
Reasoning: tachypnoea, SpO2 93% on 4 L, tachycardia and absent left basal breath sounds with radiographic collapse indicate secretion retention and volume loss, not deconditioning. Walking a patient whose lobe has not re-expanded raises oxygen demand and rarely fixes the collapse.
Sequence:
- Coordinate analgesia: ask the nurse to time a morphine bolus 20–30 minutes before the session and confirm the PCA is functioning.
- Position for the left lower lobe: right side-lying with a slight head-down tilt if tolerated after sternotomy, or semi-prone if the team agrees, to improve ventilation–perfusion matching.
- Supported huffing with a pillow splint: two or three huffs with pauses, plus deep breathing with an inspiratory hold or incentive spirometry; consider intermittent positive pressure breathing if inspiratory volumes stay low.
- Reassess SpO2 and breath sounds; if improved, sit him out on the bed edge with the drain below insertion level and the pacing wires secured.
- Mobilise in the second session once oxygenation and pain are controlled.
Stop criteria: SpO2 below 90%, respiratory rate above 30, new arrhythmia, sudden drain output, or sharp sternal pain. Document the sequence and the objective change so the next session builds on it rather than repeating it.
2. While sitting on the edge of the bed, he becomes pale and dizzy. Blood pressure falls to 88/54 mmHg and SpO2 to 88%. What do you do, and what is your differential?
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Treat it as an adverse event, not as orthostatic intolerance to be worked through.
Immediate actions: return him to supine with legs elevated, stay with him, call the nurse, apply oxygen to keep SpO2 at or above 92%, and check pulse, conscious level, capillary refill and the monitor. Do not leave him alone and do not attempt to re-mobilise the same day.
Differential - look for a cause before labelling it postural:
- Bleeding or tamponade: check chest drain volume and rate, look for rising central venous pressure, muffled heart sounds, pulsus paradoxus.
- Arrhythmia: atrial fibrillation is common on day 2–3 after CABG; check the monitor and pacing wires.
- Drug effect: recent morphine bolus plus residual anaesthetic, or antihypertensives.
- Hypovolaemia or dehydration, particularly with diabetes and perioperative fluid shifts.
- Simple orthostatic intolerance: only if observations recover promptly on lying flat and there is no other finding.
Afterwards: document time, position, observations before, during and after, action taken and who was informed; complete an incident report per MOH policy. The next attempt should be shorter, with bed-edge or tilt-table progression, continuous oximetry and the nurse present. Tell his wife what happened and why, in plain language.
3. His wife asks whether he should be resting completely. What sternal and activity advice do you give for the next 6–8 weeks, and how evidence-based is it?
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Give a clear, individualised rule set - and be honest that the numbers are precautionary.
Standard advice after median sternotomy:
- For 6–8 weeks avoid lifting more than about 5 kg, avoid pushing or pulling with the arms (heavy doors, shopping trolleys, vacuuming), avoid single-arm loading and avoid end-range shoulder extension or abduction under load.
- Splint the chest with a pillow for coughing, huffing and getting out of bed.
- Keep walking daily, build distance gradually, and use the arms below shoulder height for light daily tasks.
Mechanism: the sternum is wired, but bony union takes roughly 6–8 weeks, and shear forces are greatest with pushing, pulling and unilateral arm work. The widely quoted 5 kg limit is a precaution derived from consensus, not a measured threshold.
Evidence: no high-quality trial defines safe load limits; small studies and expert commentary suggest some traditional restrictions can be relaxed in low-risk patients, while over-restriction produces shoulder stiffness, fear of movement and deconditioning. Frame the advice as risk management, check the surgeon's protocol, which takes precedence, and put it in writing in Arabic and English.
Answer the wife directly: complete rest is not the goal - daily walking and active secretion clearance are part of recovery. Give her a role: walking with him, reminding him to splint, and watching for breathlessness or chest pain.