Patient-Controlled Regional Analgesia (PCRA) at Home
Effective management of pain may make the difference between surgery being performed on an in-patient or day care basis. The primary goal of postoperative pain management is the provision of good analgesia with minimal or no adverse effects. Since use of opioids is associated with dose-dependent increase in incidence and severity of adverse effects especially respiratory depression opioid-sparing strategies including use of non-opioid analgesics and regional techniques are particularly important in ambulatory patients.
By avoiding opioids regional anesthesia techniques provide excellent analgesia in an alert, co-operative patient untroubled by nausea. Regional anesthesia techniques are among the most effective and versatile means for providing relief of acute pain. Peripheral nerve blocks can provide excellent analgesia over a limited field and with minimal systemic effect. Such blocks allow early ambulation and are indicated in increasing number of day surgery patients. Regional techniques are particularly useful in pediatric patients because they reduce or eliminate the need for repeated injections of parenteral opioids. Catheter techniques are possible for nearly all nerve blocks. In general peripheral nerve blocks are easy to perform, inexpensive and safe but are underused for postoperative analgesia (1). Wound infiltration is perhaps the simplest method for providing analgesia, the technique has been studied mainly in patients undergoing minor orthopaedic and plastic surgery but it may also have a morphine-sparing effect in the control of pain following major surgery.
For most day-surgery patients, postoperative pain can be managed adequately at home with conventional oral analgesics, such as paracetamol, nonsteroidal antiinflammatory drugs (NSAIDs), and weak opioids. However, for moderate to severe pain, this treatment may be inadequate. Our study of 1030 patients undergoing a variety of day-surgical procedures (2) showed that approximately 30% of patients experienced moderate to severe pain at home. Severe pain was experienced by many patients who underwent the following surgeries: orthopaedic (knee, shoulder, iliac bone graft, maxillofacial, halux valgus), breast augmentation, inguinal hernia, and varicose veins. The problem of postoperative pain at home has been recognized in several recent studies. We have described a technique using an elastometric balloon pump, which allows the patient to self-administer local anesthetic analgesia at home (3). The technique involves the placement of a multihole, thin (22-gauge) epidural or Perifix brachial plexus catheters (B. Braun, Melsungen, Germany) subcutaneously into the surgical wound, subacromially, intra-articularly or in the axillary brachial plexus sheath (Table 1). The catheter is tunnelled 4-5 cm subcutaneously by the surgeon and firmly secured on the skin by sterile tape. Axillary brachial plexus catheters are placed and secured in position by anesthesiologists. The catheters are introduced 3-5 cm within the sheath and secured to the skin by transparent dressing and tape.
Using aseptic technique the catheters are connected to a 50 mL or 100 mL elastometric (balloon) pump (Fig. 1) with the appropriate concentration and volume of local anesthetic drug (Home pump®, I-Flow Corporation, Lake Forest, CA, USA). The balloon pump is filled with a volume of local anesthetic to provide 10 doses for postoperative pain management. Postoperatively, when the patient feels pain he starts the local anesthetic infusion by opening the clamp. The patient stops the infusion by closing the clamp after the prescribed time (usually 6 min) or earlier if he is satisfied with pain relief (Fig. 1). When the patient does not need analgesia any further, he removes the tape, pulls out the catheter and discards the pump. In most cases the patient self-administers the first dose in the PACU.
Bupivacaine or ropivacaine 0.125% was used in brachial plexus catheters, in all other catheters 0.25% concentration was used. The 0.125% solution was used to reduce or avoid the risk of possible injury due to excessive motor block. The maximum volume of local anesthetic allowed for each administration was 2.5 mL for maxillofacial surgery, 5-10 mL for surgical wounds, 10 mL for the remaining procedures. An appropriate pump (50 mL or 100 mL) filled with local anesthetic to provide 10 doses at home was given to the patient before discharge. The patient was instructed to avoid using the pump more than once every hour. Follow-up consisted of evaluation of pain relief at home, pump function, use of rescue medication and overall satisfaction/dissatisfaction with the technique.
Pain relief was graded good to excellent by 90% of patients. Onset of analgesia was experienced within 5 min, the duration of analgesia after each administration of local anesthetic varied from 2-8 h. Patient follow-up did not reveal any infection or any other major problem with the technique, patient satisfaction was very high. To date over 500 patients undergoing a variety of surgical procedures (Table 1) have been treated with PCRA without any major complications. Controlled trials are in progress to compare this technique with traditional methods and to evaluate the optimal concentration and volume of local anesthetic.
The main concern with this device is that the entire volume of local anesthetic will be delivered if the patient accidentally fails to close the clamp. This has happened in one patient with subacromial catheter and in one patient who had two subcutaneous catheters after breast augmentation surgery. None of the patients had any adverse effects. In a recent study it was demonstrated that subacromial administration of high doses of ropivacaine (500 mg) for pain relief after shoulder surgery resulted in blood levels (0.07-0.2 mg/L) which were well below concentrations reported to produce CNS toxic symptoms (0.34-0.85 mg/L) (4).
Recent controlled trials have demonstrated the efficacy and safety of incisional catheter PCRA in patients undergoing Caesarean section (5), abdominal hysterectomy (6) and inguinal hernia repair (7).
Studies are necessary to evaluate the optimal concentration and volume of local anesthetic and also the possible role of adjuvant drugs. The importance of adequate patient information is emphasized (Table 2).
References
1. Horlocker TT. Peripheral nerve blocks - regional anesthesia
for the new millennium (Editorial). Reg Anesth Pain Med 1998;23:237-240.
2. Rawal N, Hylander J, Nydahl PA, Olofsson I, Gupta A. Survey of postoperative
analgesia following ambulatory surgery. Acta Anaesthesiol Scand 1997;41:1017-1022.
3. Rawal N, Axelsson K, Hylander J, Allvin R, Amilon A,
Lidegran G, Hallén J. Postoperative patient-controlled local anesthetic
administration at home. Anesth Analg 1998;86:86-89.
4. Axelsson K, Johanzon E, Gupta A, Rawal N, Lidegran
G, Nordenson U, Sjövall J. Subacromial administration of high doses of
ropivacaine after shoulder surgery. IMRAPT 2000;12: 191.
5. Zohar E, Fredman B, Shapiro A, Rawal N, Jedeikin R. The analgesic efficacy
of patient controlled ropivacaine instillation following Caesarean section.
IMRAPT 2000;12:249.
6. Zohar E, Fredman B, Shapiro A, Philipov A, Jedeikin R. The analgesic efficacy
of patient controlled bupivacaine instillation following total abdominal hysterectomy.
IMRAPT 2000;12:250.
7. Vintar N, Požlep G, Rawal N, Godec M, Rakovec S. Incisional analgesia
by self-administration of local anaesthetic solution on demand after inguinal
hernia repair: comparison of bupivacaine and ropivacaine. IMRAPT 2000;12:257.
Narinder A. Rawal, MD
| Table 1. Type of surgery and site of catheter placement for PCRA | |
|
Surgery |
Site of catheter placement |
|
Hand surgery |
•
Brachial plexus sheath • Surgical wound |
|
Shoulder surgery |
•
Interscalene block • Subacromial • Intraarticular |
|
Breast surgery (augmentation, mastectomy) |
• Surgical wound |
|
Bone harvesting |
• Supra periosteal (iliac crest) |
|
Inguinal hernia |
• Surgical wound (subcut., subfascial) |
| Maxillo-facial surgery |
• Supra periosteal |
| Obst. Gyn. Surgery (C. section, hysterectomy) |
• Surgical wound
|
|
Miscellaneous |
• Surgical wound |
| Table 2. Patient instructions for postoperative PCRA at home | |
Inform
the patient about the technique and how "balloon pump" works (oral
and written information). Information should also include the following:
• Importance of opening and closing the clamp at prescribed times (use of a timer is encouraged) Provide the name and
telephone (and beeper) number(s) of physician to be contacted in case
of local anaesthetic toxicity symptoms or other problems Ask patient to return follow-up data about technique and satisfaction in self-addressed envelope Telephone follow-up day after surgery by a nurse or physician |
Self-administration of the local anaesthetic solution by a patient. On opening the clamp (a), the solution starts running into the . After the prescribed time (usually 6 min), the patient closes the clamp (confirmed by a clickingcatheter sound) to stop the infusion (b). The patient is encouraged to use a timer as a reminder to close the clamp.
