Compare the advantages and disadvantages of PCA opioids with those of intramuscular opioids

Compare the advantages and disadvantages of PCA opioids with those of intramuscular opioids.

The idea behind PCA is to allow a patient to achieve a plasma opioid concentration in their “therapeutic window”, which is the plasma level where they are comfortable but not suffering from side-effects. This “therapeutic window” is highly variable between patients. By titrating to their own level of analgesia, patients using PCA can achieve individual plasma opioid concentrations that provide pain control without the peak and trough levels seen with intra-muscular opioids. This avoids periods of both profound sedation and inadequate pain control. PCA also provides the psychological advantage of allowing patients to influence an aspect of their care without blind dependency on medical personnel.

PCA provides a convenient method of increased dosing immediately prior to painful events, such as coughing and mobilizing. During the immediate postoperative period, patients utilizing PCA use smaller amounts of opioids than patients receiving intramuscular injections, and benefit from the absence of painful intramuscular injections. By reducing the total amount of opioids and by avoiding large intramuscular doses, opioid side-effects such as sedation, nausea, vomiting, and respiratory depression are reduced. Nursing time devoted to responding to a patient’s call for analgesics, assessing the need for medication, checking the orders, signing out, and administering the opioid is decreased, thereby improving nursing efficiency.

There are disadvantages to the use of PCA. The pumps and disposable tubing are expensive. Patients must be instructed in the proper use of PCA prior to the use of the device. PCA is an excellent way to maintain analgesia; however, the patient needs to be bolused to comfort with opioids prior to the start of PCA therapy. Improper pro-gramming or pump malfunction can cause overdosing or underdosing. Opioid side-effects such as nausea, vomiting, sedation, and respiratory depression can occur, although with a decreased incidence when compared with intra-muscular opioid administration. Potential for overuse and abuse still exists.