Patient-controlled drug delivery for acute postoperative pain management: a review of current and emerging technologies.

Postoperative pain management has dramatically improved with the advent of patient-controlled analgesia (PCA) delivery. The optimal PCA system would encompass several key characteristics, including consistent efficacy across a number of surgeries; safety of both the analgesic drug delivered and the delivery system; ease of setup, maintenance, and administration; patient comfort during analgesic delivery; avoidance of analgesic gaps; minimal invasiveness; and it would be associated with high patient satisfaction. Existing PCA modalities (using intravenous or epidural routes) encompass some of these characteristics (e.g., they have demonstrated efficacy across a number of surgeries); however, they are limited by the need for an indwelling catheter and the time and resources required for system setup and use. Device programming-related medication errors by hospital staff are an unfortunate risk, and could lead to significant harm. New PCA technologies are on the horizon that address some of the limitations to existing modalities; however, the added complexity of these newer systems are a concern, and their benefits and drawbacks remain to be assessed. These technologies include "smart" intravenous PCA infusion pumps to improve the safety of analgesic administration; needle-free options, such as the fentanyl HCl iontophoretic transdermal system for transdermal delivery; and a number of PCA devices for intranasal delivery, as well as several new options for patient-controlled regional analgesia. This review will discuss the benefits and drawbacks of both existing and emerging PCA modalities in the context of the ideal PCA system, and provide a critical evaluation of their use in postoperative settings.