PCA
Formal Definition
Patient-Controlled Analgesia; a method of pain management in which the patient self-administers pre-programmed doses of IV or epidural analgesic (typically morphine, hydromorphone, or fentanyl) by pressing a button; the pump is programmed with a demand dose, lockout interval, and optional background infusion; allows rapid, personalized pain titration for post-operative and acute severe pain.
How It's Used on the Ward
"PCA" or "pain pump" or "they have a PCA button" — the pump with the patient-controlled button for on-demand pain medication.
Example
""Post-thoracotomy patient with severe pain, unable to deep breathe or cough effectively: starting PCA with morphine 1mg demand dose, 6-minute lockout, no basal rate. Respiratory therapy for incentive spirometry. PCA must be patient-controlled only — do not allow family members to press the button.""
Clinical Context
Critical safety rule: PCA is designed to be patient-controlled only. Sedated or oversedated patients cannot press the button — this is the built-in safety mechanism. Family-controlled PCA (PCAA) bypasses this safeguard and risks overdose. Monitor: pain scores, sedation scores (RASS), respiratory rate, oxygen saturation every 1–2 hours for first 12 hours. Naloxone at bedside for all patients on PCA. Background infusion: avoid in opioid-naive patients (increases sedation and respiratory depression risk); appropriate for opioid-tolerant patients. Transition to oral: convert 24-hour PCA usage to oral equivalents when patient tolerating PO.