Saturday, April 2, 2011

Opioid Analgesics : Principles of anesthesia in the postoperative period

postoperative period
The fight against pain is one of the most important problems in the postoperative period. Effective opioid analgesics promotes early rehabilitation of patients reduced the incidence of postoperative complications and chronic pain syndromes.

Currently, there are a wide range of drugs and drug-free pain relief, but many studies in different countries have shown a lack analgesia early postoperative period, almost 50% of patients. Therefore, the knowledge of modern principles of anesthesia after surgery is of great practical importance.

Stages of adequate pain relief are:

1. Preoperative assessment of the intensity and duration of pain

2. Construction plan of treatment of pain (analgesic (s), route of administration, frequency, etc.)

3. Treatment of pain.

4. Postoperative evaluation of the effectiveness of pain relief (to adjust the plan for treatment of pain in low analgesia).

To determine the quality of analgesia after surgery most widespread visual analogue scale (Fig. 1). The patient puts on the vertical lines mark the appropriate level of pain. Analgesia found to be adequate if the patient does not note pain at rest and during movement, coughing occurs moderate pain, not restrict them.

Opioid analgesics implement its action through opioid receptors located at the spinal and supraspinal levels, and are a major group of drugs for the treatment of pain in the postoperative period.

At the same time after major intracavitary surgery to achieve adequate analgesia in each third patient required the introduction of opioids in doses exceeding the recommended standard. Increasing the dose of opioids is accompanied by severe side effects (drowsiness, respiratory depression, nausea, vomiting, paresis of the gastrointestinal tract, urinary disorders), so it is now recognized that monotherapy with opioids are not always effective enough, and sometimes even dangerous.

In addition, the traditional subcutaneous and intramuscular injection is difficult to maintain an optimal concentration of opioids in the plasma, which may be accompanied by a respiratory depression, or inadequate anesthesia.

Bolus intrathecal opioids or epidural analgesia provides good up to 24 hours, but even small doses of drugs administered (ten times less than with intramuscular) may be accompanied by adverse and toxic effects.

Tramadol (Tramal)

- this is an opioid agonist, standing alone among all members of this class of opioids, primarily because unlike them he does not belong to a drug. This is confirmed by extensive clinical experience of its use worldwide, and special research potential of its drugs.

In contrast to other opioid agonists Tramadol has a dual mechanism of action. Established that the analgesia induced by tramadol is not completely eliminated by opioid antagonist naloxone, and along with the opioid mechanism is implemented by additional inhibition of pain impulses, with the participation of serotonin-and adrenergic systems. Ie on the mechanism of analgesic action of tramadol are not completely identical to other opioid agonists.

The analgesic potential of tramadol according to different authors, ranging from 0.1 to 0.2 on the capacity of morphine, it is equal to or slightly exceeds the capacity of codeine, on the effectiveness of 50 mg of tramadol equivalent of 1000 mg metamizol, ie Tramadol belongs to analgesics intended for the treatment of pain of a strong and moderate intensity.

In numerous studies have not found significant respiratory depression in postoperative patients under the influence of Trueman in the range of therapeutic doses of 0.5 to 2 mg per 1 kg of body weight, even after intravenous bolus administration, whereas morphine at a therapeutic dose of 0.14 mg / kg significantly and significantly reduces respiratory rate and increase the voltage of CO2 in exhaled air.

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