[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Nursing](https://durgical.com/en/nursing/) › [Critical care](https://durgical.com/en/nursing/areas/critical-care/) › After heart surgery in the ICU: bleeding, tamponade, rewarming, pacing wires and chest drains

# After heart surgery in the ICU: bleeding, tamponade, rewarming, pacing wires and chest drains

- Safe practice

After heart surgery the nurse watches bleeding, temperature, rhythm and output, alert to tamponade, the emergency ruled out first.

Updated Nov 13, 2026

## Key points

- Low output after heart surgery: tamponade is ruled out first.
- Blood or clot in the mediastinum without signs of systolic or diastolic dysfunction raises the suspicion of tamponade: report it.
- Hypothermia causes arrhythmias, shivering, high vascular resistance and poor clotting; rewarming dilates vessels and can drop the pressure.
- Low potassium and magnesium cause ectopic beats; low ionised calcium lowers cardiac output and pressure.
- Pacing wires: system checked at least daily; after their removal, watch closely for 24 hours for signs of tamponade.

## What it is

After heart surgery the patient arrives in the ICU sedated and ventilated, with an arterial line, usually a central or pulmonary artery catheter, chest drains, a urinary catheter and often temporary pacing wires. The first hours are the riskiest: bleeding, low cardiac output, tamponade, cold and rewarming, arrhythmias and electrolyte shifts. The nurse receives a structured handoff from surgery and anaesthesia, assesses the patient system by system, and repeats the checks often, comparing with the last ones. Care of the chest drains and of temporary pacing has its own pages, and ward care after the ICU (sternal wound, mobilisation, going home) is on the med-surg page.

## What it requires

- A structured handoff from the surgical and anaesthesia teams: procedure, bleeding, drugs running, pacing, problems.
- Continuous ECG, arterial pressure, filling pressures, temperature, saturation and hourly drain and urine output.
- Protocols for bleeding, rewarming, electrolytes, glucose and transfusion.
- A defibrillator and pacing box ready at the bedside.

## How it is applied (and why)

- Receive the handoff and assess rhythm, pressure, filling pressures, temperature, drips, ventilator, drains and neurological state — it gives the baseline.
- Measure and record drain output as the institutional protocol says, and report output above the limits it sets — the team plans bleeding care from it.
- Watch for low cardiac output: tamponade is the first cause to exclude — report falling pressure or output at once.
- Rewarm as the protocol says and treat shivering as ordered — cold worsens bleeding and rhythm; warming can drop the pressure.
- Check potassium, magnesium and ionised calcium as ordered and report abnormal values — they affect rhythm and contractility.
- Watch the rhythm: atrial fibrillation lowers output; know which wires are atrial and which ventricular — pacing restores rate and AV timing.
- Handle the wires and pacing box as the institutional protocol says, and check settings and thresholds at least daily — a poorly sensing system is dangerous.
- Measure urine output hourly and report a fall — low output and inflammation after bypass can injure the kidneys.
- Check glucose as ordered — stress and some vasoactive drugs raise it.
- After wire removal, take vital signs closely for 24 hours and report new low pressure at once — bleeding into the pericardium can cause tamponade.

## In nursing practice

- Report a cardiac index or blood pressure below the goals the team set, and a heart rate outside the range ordered.
- Bleeding is managed by a defined plan: warming, pressure control, laboratory tests and transfusion as ordered.
- An enlarged mediastinal shadow on the chest film or echo findings support the suspicion of tamponade; the surgeon decides on re-exploration.
- Ventricular ectopy, new atrial fibrillation or a change in the paced rhythm are reported with an ECG strip.
- Explain to the family the lines, tubes and alarms they will see, and when they can visit.

## Common mistakes

- Treating low cardiac output with an inotrope before tamponade has been ruled out.
- Treating hypotension during rewarming without considering bleeding or tamponade.
- Leaving a poorly sensing pacing system switched on without reporting it.
- Not checking electrolytes before treating arrhythmias.
- Losing the trend because drain output and urine are not recorded hourly.

## Test yourself

Think of the answer, then tap the question to see it.

## Which emergency must be ruled out first in low cardiac output after heart surgery?

Cardiac tamponade, from blood and clot collecting around the heart.

## Why does hypothermia matter after heart surgery?

It causes arrhythmias, shivering, high vascular resistance and impaired clotting; rewarming then dilates vessels and can lower the pressure.

## Which electrolytes are watched closely after heart surgery, and why?

Potassium and magnesium, whose low levels cause ectopic beats, and ionised calcium, whose low level lowers contractility and pressure.

## What is watched after epicardial pacing wires are removed?

Vital signs, closely for 24 hours: new low blood pressure or shock may mean tamponade and needs urgent echocardiography.

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## Elsewhere in DurgiPedia

- [Cardiac tamponade: Beck triad and pulsus paradoxus](https://durgical.com/en/clinical-exam/cardiac-tamponade-beck-triad-and-pulsus-paradoxus/)

## Connections

## Related 4

- [Chest tube: assisting insertion, the drainage system and care](https://durgical.com/en/nursing/chest-tube-assisting-insertion-the-drainage-system-and-care/)
- [Temporary pacing (transcutaneous and transvenous): set-up, capture, sensing and safety](https://durgical.com/en/nursing/temporary-pacing-set-up-capture-sensing-and-safety/)
- [Postoperative complications: recognising them and when to call](https://durgical.com/en/nursing/postoperative-complications-recognising-them-and-when-to-call/)
- [Ward care after heart surgery (bypass, valve replacement): sternal wound, lungs, mobilisation and going home](https://durgical.com/en/nursing/ward-care-after-heart-surgery-sternal-wound-lungs-mobilisation-and-going-home/)

## Related conditions 2

- [Cardiac tamponade](https://durgical.com/en/conditions/cardiac-tamponade/)
- [Myocardial Infarction (Heart Attack)](https://durgical.com/en/conditions/myocardial-infarction/)

[← All of nursing](https://durgical.com/en/nursing/)

Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order.

Sources: [Postoperative Care of the Cardiac Surgical Patient (DiMarco RF Jr, in Surgical Intensive Care Medicine, 2010:535-566)](https://pmc.ncbi.nlm.nih.gov/articles/PMC7120630/) (Springer, open access in PubMed Central, 2010); [Temporary epicardial pacing after cardiac surgery (Gillham MJ, Barr TM, BJA Education 2023;23(9):337-349)](https://pmc.ncbi.nlm.nih.gov/articles/PMC10433321/) (BJA Education, open access in PubMed Central, 2023).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/nursing/after-heart-surgery-in-the-icu-bleeding-tamponade-rewarming-pacing-wires-and-che/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/nursing/after-heart-surgery-in-the-icu-bleeding-tamponade-rewarming-pacing-wires-and-che/