[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Nursing](https://durgical.com/en/nursing/) › [Perioperative nursing](https://durgical.com/en/nursing/areas/perioperative/) › Postoperative complications: recognising them and when to call

# Postoperative complications: recognising them and when to call

- Assessment

Most postoperative complications give early warning signs; the nurse finds them by regular assessment and calls for help in time.

Updated Nov 12, 2026

## Key points

- Respiratory: shortness of breath, fast breathing and low oxygen saturation; atelectasis comes mainly from shallow breathing due to pain or immobility.
- VTE: a swollen, painful, warm or red leg (DVT); sudden breathlessness, chest pain, fast heart rate or fainting (pulmonary embolism).
- Bleeding: soaked dressing or rising drain output, with a fast pulse, low blood pressure and anxiety as blood loss grows.
- Urinary retention: no voiding, lower abdominal pain or fullness; confirmed by examination or bladder ultrasound per protocol.
- Ileus, wound infection or dehiscence, delirium and sepsis are covered in the table and the call criteria.
- Use the early warning score and SBAR; call early rather than wait.

## What it is

The main complications after surgery are respiratory (atelectasis, pneumonia, aspiration), venous thromboembolism (deep vein thrombosis and pulmonary embolism), bleeding, urinary retention, paralytic ileus, surgical site infection and wound dehiscence, delirium and sepsis. Each has typical signs. The nurse looks for them in every assessment, uses the early warning score and escalates with SBAR. This page summarises what to look for and when to call; it does not replace medical diagnosis.

## Reference values

- Vital signs outside the protocol or NEWS2 parameters trigger escalation; the reference values are on the routine vital signs and early warning score pages.
- Systemic signs of wound infection (fever over 38 °C, malaise, new confusion, increasing pain, spreading redness or swelling) need urgent review.
- Sepsis signs: confusion, shortness of breath, fast heart rate or weak pulse, fever or feeling very cold, clammy skin, extreme pain.
- About half of people with a deep vein thrombosis have no symptoms.

## What you need

- Vital signs, saturation and the early warning score chart.
- Inspection of the wound, dressings and drains; inspection of both legs.
- Intake and output chart and time of the last void; bladder ultrasound device if available.
- Abdominal assessment (distension, bowel sounds, bowel movements, tolerance of food) and a quick check of attention and orientation.

## How to measure it (and why)

- Measure vital signs and saturation and score the early warning scale: an abnormal score triggers escalation.
- Listen to breathing and ask about cough and breathlessness: atelectasis and pneumonia are frequent after surgery.
- Look at both legs for swelling, pain, warmth or redness: these may signal deep vein thrombosis.
- Check the dressing, drains and pulse: fresh bleeding with a rising pulse, falling pressure or anxiety suggests haemorrhage.
- Record the time of the last void and palpate the lower abdomen: retention is common after anaesthesia.
- Assess the abdomen for distension and bowel sounds, and ask about bowel movements and eating: these show whether bowel function is returning.
- Inspect the wound for redness, heat, pus or separating edges: infection or dehiscence needs prompt review.
- Check attention and orientation, and ask the family if the patient seems different: delirium is often quiet.
- Report with SBAR and record the findings and actions: clear escalation shortens the delay to treatment.

## Complications and what you see

| Complication | What you see |
| --- | --- |
| Atelectasis, pneumonia | Shortness of breath, fast breathing, low oxygen saturation |
| DVT / pulmonary embolism | Swollen, painful, warm or red leg; sudden breathlessness, chest pain, fast pulse |
| Bleeding | Soaked dressing, rising drain output, fast pulse, low blood pressure, anxiety |
| Urinary retention | No voiding with a full bladder, lower abdominal pain or discomfort |
| Paralytic ileus | Abdominal distension, fewer bowel sounds, constipation, difficulty eating again |
| Wound infection or dehiscence | Redness, warmth, pus, fever; edges separating, more drainage, broken sutures |
| Delirium | Sudden, fluctuating confusion, inattention, disorganised thinking; quiet or agitated |

## How to read it

- A single normal reading does not rule out a problem; look at the trend.
- Hypoactive delirium (quiet, sleepy) is the most common form and the easiest to miss.
- Coughing or straining can open an abdominal wound suddenly; teach the patient to move carefully and avoid straining the wound area.
- If organs protrude through the wound, stay with the patient, keep them still, cover the wound per protocol and call at once.

## Next step: when to call for help

- Call at once (rapid response or doctor): sudden breathlessness or chest pain, falling saturation, low blood pressure with fast pulse, heavy bleeding, new confusion with fever, organs visible through the wound.
- Call promptly: a fever over 38 °C, a swollen painful leg, no voiding with lower abdominal pain, abdominal distension with inability to eat or drink.
- Report today: a red, warm or draining wound, no bowel movement, poor intake.
- Follow the early warning score rules of your institution and record who was called and when.

## Test yourself

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

## Which signs suggest a pulmonary embolism after surgery?

Sudden breathlessness, chest pain that worsens with deep breaths or coughing, a fast or irregular heart rate, coughing blood, low blood pressure or fainting.

## What are the signs of postoperative urinary retention?

The patient has not voided and has lower abdominal pain, discomfort or a palpable full bladder; it is confirmed by examination or bladder ultrasound per protocol.

## Why is hypoactive delirium easy to miss?

Because the patient is quiet and sleepy rather than agitated, and this can be mistaken for normal postoperative sedation.

## Which signs together suggest possible sepsis?

Confusion, shortness of breath, a fast heart rate or weak pulse, fever or feeling very cold, clammy skin and extreme pain.

## Which wound signs suggest a dehiscence is starting?

Redness at the wound edges, increasing drainage, increasing pain and broken sutures, especially after coughing or straining.

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## Connections

## Related 6

- [Recognising deterioration and calling the rapid response team](https://durgical.com/en/nursing/recognising-deterioration-and-calling-the-rapid-response-team/)
- [Early warning scores (NEWS2) and when to escalate](https://durgical.com/en/nursing/early-warning-scores-and-when-to-escalate/)
- [Vital signs in nursing: when, how often and how to record them](https://durgical.com/en/nursing/vital-signs-in-nursing-when-how-often-and-how-to-record-them/)
- [Mechanical prevention of venous thromboembolism: stockings and intermittent compression](https://durgical.com/en/nursing/mechanical-prevention-of-venous-thromboembolism-stockings-and-intermittent-compr/)
- [Airway clearance: incentive spirometry, deep breathing, coughing and oscillating devices](https://durgical.com/en/nursing/airway-clearance-incentive-spirometry-deep-breathing-coughing-and-oscillating-de/)
- [The surgical wound: healing, dehiscence and infection](https://durgical.com/en/nursing/the-surgical-wound-healing-dehiscence-and-infection/)

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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 pulmonary complications: clinical and imaging insights](https://europepmc.org/article/PMC/PMC12402958) (Balkan Medical Journal, open access (Europe PMC), 2025); [About venous thromboembolism (blood clots)](https://www.cdc.gov/blood-clots/about/index.html) (Centers for Disease Control and Prevention (CDC), 2024); [Postoperative urinary retention (POUR): a narrative review](https://europepmc.org/article/PMC/PMC11033892) (Saudi Journal of Anaesthesia, open access (Europe PMC), 2024); [An outline of the management and prevention of postoperative ileus: a review](https://europepmc.org/article/PMC/PMC11175850) (Medicine (Baltimore), open access (Europe PMC), 2024); [WHO guidelines for safe surgery 2009: safe surgery saves lives](https://www.who.int/publications-detail-redirect/9789241598552) (World Health Organization (WHO), 2009); [Nursing Skills, 20.2: Basic concepts related to wounds](https://med.libretexts.org/Bookshelves/Nursing/Nursing_Skills_(OpenRN)/20:_Wound_Care/20.02:_Basic_Concepts_Related_to_Wounds) (Open RN, Wisconsin Technical College System (LibreTexts copy), 2021); [Postoperative delirium in elderly orthopedic patients: a narrative review of prevention and multidisciplinary nursing intervention](https://europepmc.org/article/PMC/PMC13366212) (Frontiers in Psychiatry, open access (Europe PMC), 2026); [About sepsis](https://www.cdc.gov/sepsis/about/index.html) (Centers for Disease Control and Prevention (CDC), 2024).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/nursing/postoperative-complications-recognising-them-and-when-to-call/