Managementof Acute Postoperative

Pain

Min Yan. M. D. Anesthesiology DepartmentNo.2 Affiliated HospitalMedical college, Zhejiang UniversityE-mail: yanminnina@hotmail.comOffice phone: 0571-87783716Hand phone: 13757118632

• After the first public demonstration of ether anesthesia at the Massachusetts General Hospital in 1846, the news that “We have conquered pain” spread around the world.

• What was not understood at the time is that the potent hypnotics merely suspend pain perception, but do little to change pain transmission.

• Analgesia, as distinct from hypnosis, is a vital and integral component of anesthesia.

• Anesthesiologists must plan for the continuum of intra- and postoperative pain.

Preparation--Patient Education

• Patients who are informed about their likely postoperative experience are much better able to cope with pain and the other discomforts of the postoperative state than those who enter the experience uninformed.

Preparation—Anesthesia Planning

• Painfree emergence ：• This is not only by means of sustainable

analgesia (epidurals and other catheter treatments), but also by careful anesthesia planning that results in a painfree or near pain-free emergence from anesthesia.

• The importance of a painfree emergence cannot be overemphasized;

Preparation—Anesthesia Planning

• Painfree emergence ：• Patients who wake from anesthesia in

severe pain, especially those who are not expecting pain, are already disadvantaged in terms of being able to control their pain—again, fear and anxiety intervene to make pain control difficult.

Pain Assessment

• Pain is a complex, multidimensional symptom resulting from a combination of tissue damage and nociception, previous pain experience, personal beliefs, culture and mood.

• This explains why patients with the same degree of tissue damage can differ widely in their pain reports.

Pain Assessment

• Verbal numeric rating scales ：• The patient is asked to rate pain on a

numeric scale, usually 0–10, where 0 is no pain and 10 is the worst pain imaginable.

Pain Assessment

• Visual analog scales ：• The patient marks on a measured line

labeled “no pain” at one end and “worst pain imaginable” at the other.

Pain Assessment

• Assessment of pain in children ：• the Wong-Baker FACES Pain Rating

Scale ：

Postoperative analgesia

• Postoperative analgesia is provided to minimize patient discomfort and anxiety ， attenuate the physiologic stress response to pain ， enable optimal pulmonary toilet ， and enable early ambulation.

Postoperative analgesia

• Intravenous route ：• As needed （ p.r.n ）• Patient Controlled Analgesia （ PCA ）

• Continuous narcotic infusions

• Epidural infusions

• Oral agents

Postoperative analgesia

• Intravenous route ：• As needed （ p.r.n ）

• The intermittent administration of intravenous or intramuscular narcotics has the potential disadvantages of being given too infrequently ， too late ， and in insufficient amounts to provide adequate pain control.

• Morphine 2-4mg IV, q 30-60min, q 30-60min• Meperidine 50-100mg, q 30-60min• Ketorolac 15-30mg, q 6h

Patient Controlled Analgesia （ PCA）

• Simple though it seems, PCA technology represents a huge advance in acute pain management.

• PCA satisfies the needs of patients to receive pain medication easily and quickly, when needed.

• Serum drug levels from frequent small dosing using PCA compared with large, intramuscular or intravenous dosing given every 2–4 hours. Ideally, serum drugs levels are kept within the “analgesic” range, avoiding the high peaks associated with oversedation and respiratory depression and the low troughs associated with inadequate analgesia. Frequent small dosing would not be practicable without PCA.

Postoperative analgesia

• Continuous narcotic infusions ：• Are used periodically to treat patients

requiring sustained high serum narcotic levels.

Postoperative analgesia

• Epidural infusions:

• Indications:• Including patients having thoracic or abdominal surgery,

patients having lower-limb surgery in whom early mobilization is important, patients having lower-body vascular procedures in whom a sympathetic block is desirable, and patients with compromised cardiac or

pulmonary function.

Postoperative analgesia

• Epidural infusions:

• Narcotics, local anesthetics ， or a mixture of the two may be infused continuously through catheters placed in the lumbar or thoracic epidural space

Postoperative analgesia

• Oral agents ：• Acetaminophen+codeine

• Acetaminophen+oxycodone

• Aspirin+oxycodone

• Acetaminophen+propoxyphene

Postoperative analgesia—side effects and complications

• Overseation and respiratory depression

• Apneic

• Hypotension

• Nausea and vomiting

• Pruritis

• Momoamine oxidase inhibitors

Thank you!