Epidural PCA

Epidural PCA is maintained for 2-4 days, depending upon the procedure and potential benefit to the patient. Most patients make a smooth transition to oral opioids such as oxycodone or oxycodone-acetaminophen compounds, or to low-dose IV-PCA therapy for some who remain nil per os (NPO) for extended periods. For opioid-dependent or chronic... 

Assess epidural PCA use. If minimal, educate the patient to press the bolus button every 6 minutes as needed. If approaching the maximmn, consider increasing the bolus dose by 25-33%. Also consider an epidural loading dose of 10 mL of infusion solution, which may be repeated 15 minutes later. 

Opioids maybe administered in a variety of routes including oral (tablet and liquid), sublingual, rectal, transdermal, transmucosal, intravenous, subcutaneous, and intraspinal. While the oral and transdermal routes are most common, the method of administration is based on patient needs (severity of pain) and characteristics (swallowing difficulty and preference). Oral opioids have an onset of effect of 45 minutes, so intravenous or subcutaneous administration maybe preferred if more rapid relief is desired. Intramuscular injections are not recommended because of pain at the injection site and wide fluctuations in drug absorption and peak plasma concentrations achieved. More invasive routes of administration such as PCA and intraspinal (epidural and intrathecal) are primarily used postoperatively, but may also be used in refractory chronic pain situations. PCA delivers a self-administered dose via an infusion pump with a preprogrammed dose, minimum dosing interval, and maximum hourly dose. Morphine, fentanyl, and hydromorphone are commonly administered via PCA pumps by the intravenous route, but less frequently by the subcutaneous or epidural route. 

Dosages and routes of administration Morphine is available in different salt forms but the hydrochloride and sulfate (Vermeire and Remon, 1999) are used preferentially. The compound can be administered by the oral, parenteral or intraspinal route. Oral application is preferred for chronic pain treatment and various slow release forms have been developed to reduce the administration frequency to 2-3 times per day (Bourke et al., 2000). Parenteral morphine is used in intravenous or intramuscular doses of 10 mg, mostly for postoperative pain and self-administration devices are available for patient-controlled analgesia (PCA). Morphine is additionally used for intraspinal (epidural or intrathecal) administration. Morphine is absorbed reasonably well in the lower gastrointestinal tract and can be given as suppositories. 

Medico-technical instruments such as infusion pumps can be used in PCA (patient-controlled analgesia, Fig. 1) to provide patient-orientated and therapy as required, e.g. with morphine injection solutions. Depending on the patients perception of pain, they may add small doses of analgesics to the basic infusion by means of an electrically controlled infusion pump. The physician specifies the basic dose, which is infused independent of patient demands, the boluses that can be demanded, an hourly maximum dose and a refractory time that cannot be reduced between two doses. The infusion may be given intravenously, subcutaneously, epidurally or intraspinally. 

FIGURE 17-3 T Schematic illustration of PCA spinal delivery. The catheter delivers the analgesic into either the epidural or intrathecal [subarachnoid] space. Catheters for long-term use are tunneled under the skin (dashed line) and can either be connected directly to an implanted PCA pump, or exit the anterior-lateral flank for connection to an external pump. 

Thus, PCA techniques have been shown to have certain advantages over more traditional methods such as intermittent IM injection or continuous epidural infusion. One must also consider that PCA decreases the need for other health professionals (physicians, nurses, pharmacists) to be directly involved in... 

Sumikura H, van de Velde M, Tateda T. Comparison between a disposable and an electronic PCA device for labor epidural analgesia. J Anesth. 2004 18 262-266. 

Yavuz L, Eroglu F, Ozsoy M. The efficacy of intravenous versus epidural tramadol with patient-controlled analgesia (PCA) in gynecologic cancer pain. EurJ Gynaecol Oncol. 2004 25 215-218. 

In a randomized, placebo-controlled, double-blind study of the relative efficacies of patient-controlled analgesia (PCA) regimens (63), 60 patients undergoing elective total hip or knee replacement were randomly allocated to receive epidural diamorphine 2.5 mg followed by a PCA bolus 1 mg with a 20-minute lockout (group 1), subcutaneous diamorphine 2.5 mg followed by a PCA bolus 1 mg with a 10-minute lockout (group 2), or epidural diamorphine 2.5 mg in 4 ml of 0.125% bupivacaine followed by a PCA bolus of 1 mg diamorphine in 4 ml... 

The addition of bupivacaine and/or adrenaline to epidural fentanyl analgesia has also been studied in 100 women after elective cesarean section. AU received fentanyl (3 pg/ml) by patient-controUed analgesia (PCA) for 48 hours and were randomly assigned double-bUnd to receive either bupivacaine 0.01%, ephedrine 0.5 pg/ml, both, or neither (25). Patients who received fentanyl alone made more attempts at PCA than the other groups, suggesting that this regimen was less effective and the higher dose of fentanyl used perhaps contributed to a... 

In a randomized, double-blind study in 56 patients, continuous infusion of fentanyl (1 qg/kg/hour or 0.5 pg/ kg/hour) and bupivacaine 0.1 mg/kg/hour, with intravenous morphine PCA as rescue analgesia, produced better pain relief after knee hgament operations than epidural saline combined with intravenous morphine PCA (26). There was a non-significant increase in nausea in the fentanyl group. 

In another comparison of a single dose of epidural morphine with PCA epidural fentanyl after cesarean section, pain relief and the incidence of nausea were similar, but pruritus was significantly less with fentanyl (SEDA-18, 83). 

In a double-blind, double-dummy, sham-control-led study including 168 total knee arthroplasty patients, subjects were assigned to receive DepoDur 30 mg, DepoDur 20 mg, or sham epidural injection, to compare DepoDur with morphine PCA. DepoDur patients experienced less pain and required less opioid rescue as compared to morphine PCA patients [5]. 

If the patient is highly opioid-dependent, consider administering a more concentrated epidural infusion (hydromorphone 20-30 pg/mL plus bupivacaine 1/16 %). In addition, opioid-dependent patients will almost always require oral or IV opioid supplementation. They may benefit from combined IV-PCA hydromorphone (0.4-1 mg q 6 min) plus a continuous epidural infusion of more concentrated solution. Alternatively, parenteral doses of morphine... 

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