Pain in the ICU is commonly multi-factorial, arising from:

1. 1 Pre-existing disease (e.g. recent surgery and myeloma).

2. 2 Therapeutic devices (e.g. drains, non-invasive ventilation masks and endotracheal tubes).

3. 3 Invasive procedures (e.g. intravenous access).

4. 4 Routine nursing care (e.g. airway suctioning, physiotherapy, mobilization and dressing changes).

5. 5 Monitoring (e.g. oesophageal Doppler).

In order to avoid patient suffering, these nociceptive stimuli require suitable analgesia, using adequate dosages and appropriate regimens.

Why are patients in pain?

1. 1 Staff fear of potent analgesics, particularly with regard to the potential:

2. — Obscuring of diagnosis.

3. — Occurrence of adverse side effects (cardiovascular system (CVS), respiratory, gastrointestinal (GIT) system).

4. — For drug addiction.

5. 2 Staff difficulties with pain assessment.

6. 3 The multi-factorial nature of influences affecting the patients' perception of pain, specifically:

7. — Expectation of pain.

8. — Prior pain experiences.

9. — Emotional state.

10. — Cognitive processes.

What are the complications of inadequate pain relief?

Inadequate analgesia contributes to:

1. 1 Exhaustion, disorientation and agitation, consequent upon insomnia.

2. 2 An enhanced stress response, characterized by tachycardia, increased myocardial oxygen consumption, hypercoagulability, immunosuppression and persistent catabolism.

3. 3 Pulmonary dysfunction, with guarding of muscles around painful areas leading to restrictive movements of the chest wall and diaphragm.

How can pain be assessed in the intensive care unit?

Clinical pain assessment relies heavily on subjective patient reports (Table 16.1).