Intravenous anesthesia/analgesia
Why do we need local anesthetics ?
A. Borgeat, Orthopedic University Clinic
Zurich/Balgris
Correspondence :
Alain
BORGEAT
Chief-of-Staff Anesthesia
Orthopedic University Clinic Zurich/Balgrist
Forchstrasse 340
CH-8008 Zurich / Switzerland
Tel.: ++41 1 386 11
11
Fax: ++41 1 386 16
09
Email aborgeat@balgrist.unizh.ch
In spite of
great advances in medical science, many patients are still concerned about
having operative procedures, because of their fear of the ensuing postoperative
pain (1,2). It is a matter of historical fact, that the routine prescription of
analgesics, based upon the patient having to complain of severe pain, resulted
in satisfactory pain relief in only a minority of cases (2,3). Unrelieved
postoperative pain results in patient discomfort, long hospital stays, poor
patient outcome and greater use of health care resources. Pain is a
complication of surgery and all the means to alleviate this complication have
to be applied.
Considerable
progress in per- and postoperative patient care have been made over the years,
for example the introduction of PCA in 1980, acute pain service (APS) in 1985
and the concept of multimodal approach in 1998. The beneficial impact of recent
developments is illustrated by two surveys conducted among surgical patients in
a university hospital (4). In 1989, when asked about the severity of their pain
on the second postoperative day, 71% of those patients not managed by an APS
had moderate pain and 19% severe. Six years later after implementation of pain
treatment guidelines in the same department, 73% of the patients rated their
pain intensity as "low" and only 6% of patients rated their pain as
severe. Although great progress has been made, a considerable scope remains for
further improvement in postoperative care. Among the targets the surgeons have
to be taken into account. Indeed, a recent survey showed the need for better
education of the surgeons (5). The survey demonstrated that
- 81% of the surgeons felt
uncomfortable with pain management
- 50% of the surgical departments had no guidelines for the management of acute
pain
– 62% of the surgeons believed that an interdisciplinary pain service was
needed.
Anesthesiologists
have a place of choice to deal with pain. Brian Ready wrote ten years ago
"Anesthesists are a logical choice to provide pain relief in the immediate
postoperative period, since they are familiar with the pharmacology of
analgesics, ... are knowledgeable about pain pathways and their interruption
and are skilled in the techniques needed to offer multiple forms of pain
control ..."
Patient controlled analgesia (PCA)
PCA has
become the preferred technique when opioids are administered systemically.
Despite the advantages that this technique offers over more traditional techniques,
some problems remain
- inadequate analgesia with PCA has
been demonstrated in a number of studies (6,7)
- inadequate analgesia was also
reflected in patient's inability to comply with physiother-
apy (6,7)
- the incidence of nausea and vomiting remains high
- sedation may be troublesome
- delayed recovery of bowel function has been observed.
Concomitant
administration of paracetamol (8), NSAIDS (9), clonidine (10) or ketamine (11)
lead to a significant opioid-sparing effect, an early withdrawal of the PCA
device and therefore a reduction in the incidence of opioid-associated
side-effects.
However,
despite these advances in per- and postoperative pain management, room remains
for improvement. The time for regional anesthesia and local anesthetics has
come. Local anesthetics (LA) are well designed for either spinal, epidural or
peripheral nerve blocks anesthesia/analgesia.
Numerous
studies have shown that LA are associated with a better pain control, less
side-effects and a higher patient satisfaction as compare to classical intravenous
analgesia (12,13). It is important to understand the specific properties of LA
in per- and postoperative pain management.
How can we
understand the clinical advantages associated with the use of local anesthetics
? By looking at the different pain pathways which follow surgical trauma, we
may notice that two of them can be efficiently blocked only by local
anesthetics. These two are first the segmental reflex responses, responsible
for the pain associated with muscular reflex spasms, decreased thorax
compliance, bronchoconstriction, ileus and urinary retention and second the
suprasegmental reflex responses (associated with the activity of the
sympathetic system), responsible for an increased blood pressure and cardiac
output, - their involvement is demonstrated by a generalized body increase of
oxygen consumption. Opioids are ineffective to block either the segmental or
the suprasegmental responses. The advantages of central blocks are mainly better
pulmonary and gastrointestinal functions, a lower incidence of thrombo-embolic
events, and an overall reduced body need of oxygen. The advantages of
peripheral blocks, mainly in orthopedics, are linked with the possibility of
better and early effective rehabilitation; these are accompanied by a decreased
appearance of adherences and intra-articular deposits of fibrous tissue, a
lower incidence of capsular retraction and postoperative articular ankylosis.
LA can effectively block the A delta nerve fibers, which is not the case with
the opioids. It is known that periarticular structures for example are densely
linked with A delta nerve fibers, which are particularly solicited during
movement.
Regional
anesthesia with the application of LA is one of the most important components
of a multimodal and multidisciplinary approach to the management of the
surgical patient, a concept believed to offer an accurate patient management
strategy and to provide for the patient the best per- and postoperative pain
management.
References
1.
Ready
LB: Acute perioperative pain. In: Miller RD, ed. Anesthesia. Churchill Livingstone, Philadelphia 2000: 2323-50
2.
Sinatra
RS: Acute pain management and acute pain services. In: Neural Blockade in
Clinical Anesthesia and Management of Pain. Cousins MJ, Bridenbaugh PO, eds. 2nd
Ed, Lippincott-Raven, Philadelphia 1998: 793-836
3.
Warfield
CA, Kahn CH: Acute pain management. Programs in US hospitals and experiences
and attitudes among US adults. Anesthesiology 1995; 83: 1090-4
4.
Maier
C, Raetzel M, Wulf H: Audit in 1989 and 1994 of the Department of
Anaesthesiology and Intensive Care, Hospital of Christian-Albrechts-University,
Schwanenweg 21, D24105, Kiel, Germany
5.
Neugebauer
E, Hepel K, Sauerland S, Lempa M, Koch G. The status of perioperative pain
therapy in Germany. Results of a representative, anonymous survey of 1,000
surgical clinics. Chirurg 1998; 69: 461-6
6.
Sidebotham
D, Dijkhuizen MR, Schug SA: The safety and utilisation of patient-controlled
analgesia. J Pain Symptom Manage 1997; 14: 202-0
7.
Schug
SA, Fry RA: Continuous regional analgesia in comparison with intravenous opioid
administration for routine postoperative pain control. Anaesthesia 1994; 49:
528-32
8.
Schug
SA, Sidebotham DA, McGuinnety M, Thomas J, Fox L. Acetaminophen as an adjunct
to morphine by patient controlled analgesia in the management of acute
postoperative pain. Anaesth Analg 1998; 87: 368-72
9.
Etches
RC, Warriner CB, Badner N, et al: Continuous intravenous administration of
ketorolac reduced pain and morphine consumption after total hip or knee
arthroplasty. Anesth Analg 1995; 81: 1175-80
10.
Park
J, Forrest J, Kolesar R, Bhola D, et al: Oral clonidine reduces post-operative
PCA morphine requirements. Can J Anaesth 1996; 43: 900-6
11.
Royblat L,
Korotkoruchko A, Katz J, et al. Postoperative pain: the effect of low-dose ketamine in addition to
general anaesthesia. Anesth Analg 1993; 77: 1161-5
12.
Borgeat
A, Schäppi B, Biasca N, Gerber C: Patient-controlled analgesia after major
shoulder surgery. Anesthesiology 1997; 87: 1343-7
13.
Borgeat
A, Tewes E, Biasca N, Gerber C: Patient-controlled interscalene analgesia with
ropivacaine after major shoulder surgery: PCIA vs PCA. Brit J Anaesth 1998; 81:603-5