The document discusses patient-controlled analgesia (PCA) pumps which allow patients to self-administer pain medication via an intravenous line connected to a computerized pump. The pump can be programmed to provide a constant small dose of medication with additional doses available when the patient presses a button. PCA pumps are commonly used for patients recovering from surgery and help give patients control over their pain relief. Close monitoring of patients using a PCA pump is important to assess pain levels, sedation, and respiratory function.