Patient-Controlled Analgesia Pumps

A patient-controlled analgesia (PCA) pump delivers a prescribed opioid dose when the patient presses a demand button. The pump records the request, gives the dose only if the lockout interval has elapsed, and refuses additional doses during that interval. The lockout reduces repeated dosing, but it does not make opioid accumulation impossible. Morphine, fentanyl, and hydromorphone are μ-opioid receptor agonists. They reduce transmission of nociceptive signals in the dorsal horn of the spinal cord and alter how the brain perceives pain. The same receptor activity that relieves pain can suppress the brainstem drive to breathe, reduce alertness, slow gastrointestinal motility, cause nausea or vomiting, produce pruritus, and lower blood pressure. The most useful safety rule is also the simplest: the patient must be the only person who presses the button. A patient who is awake enough to recognize pain, understand the device, and request a dose can participate in the safety system. A sleeping family member cannot judge whether another dose is safe. If the patient is too sedated to press the button, giving more opioid is unsafe—even if the...