Pathophysiological mechanisms of pain syndrome
Any surgical intervention is inevitably accompanied by tissue damage, which triggers a cascade of protective and pathological reactions. The developing pain syndrome acts as a powerful psychoemotional stress factor for the operated patient.
In response to intense pain, a massive release of catecholamines into the systemic circulation occurs. This leads to pronounced changes in the cardiovascular system: the patient develops tachycardia and a corresponding increase in blood pressure.
Equally significant and extremely dangerous is the effect of pain on the respiratory system. Due to the fear of sharply intensifying pain with movements of the chest or anterior abdominal wall, reflex respiratory depression occurs. The patient begins to breathe shallowly, and the strength and overall effectiveness of the cough reflex sharply decrease, creating ideal conditions for secretion stagnation.
Pharmacological methods of analgesia
The choice of drugs for postoperative pain relief should be based on the principle of maximum analgesic efficacy with minimal suppressive effect on vital functions (especially hemodynamics and the respiratory center).
- Opioid analgesics. Used to relieve severe pain syndrome. The optimal choice is drugs that minimally depress respiration and do not cause sharp negative hemodynamic shifts. A typical representative of this group in surgical practice is fentanyl.
- Non-opioid analgesics. Used as a basic component of analgesia. Metamizole sodium is often used in surgery to help reduce the intensity of pain impulses.
Additional methods and features of treatment in elderly patients
To improve the overall quality of analgesia and reduce the pharmacological load, additional non-pharmacological and regional techniques are actively used:
- Percutaneous electrical nerve stimulation.
- Continuous epidural anesthesia.
- Acupuncture.
Elderly patients require a special and extremely careful approach. The combination of non-opioid analgesics (such as metamizole sodium) with the aforementioned additional methods is most indicated and safe for them.
Importance of adequate pain relief
The main task of pain relief in the postoperative period is the functional rehabilitation of the body. When a patient is provided with adequate pain relief, they are able to:
- Take deep breaths, expanding the lungs.
- Productively and effectively expectorate accumulated sputum.
- Exhibit early physical activity.
All these factors combined represent the most important and reliable prevention of postoperative complications.
Briefly: answers to topical questions
What groups of pharmacological drugs are used for postoperative analgesia?
- Non-opioid analgesics and paracetamol are effective drugs for basic analgesia and the elimination of acute pain.
- Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to relieve pain and aseptic inflammation.
- Opioid (narcotic) analgesics are used when non-opioid agents are insufficiently effective and to control severe pain syndrome.
- Gabapentinoids are recommended for inclusion in multimodal analgesia regimens.
- Adjuvant drugs include a single dose of dexamethasone to significantly reduce pain syndrome.
What regional anesthesia methods are used to relieve postoperative pain?
- Continuous epidural anesthesia is indicated as an additional method of postoperative pain relief.
- Epidural anesthesia is described as a safe and effective method within the structure of multimodal analgesia when there is a risk of respiratory depression.
- Local block or regional anesthesia is recommended as part of the postoperative multimodal regimen.
- Wound infiltration with local anesthetic solutions is among the recommended methods for postoperative pain relief.
- TAP block (transversus abdominis plane block) is a recommended method of postoperative pain relief after cesarean section.
- Local infiltration anesthesia is used as part of multimodal analgesia in the surgical treatment of patients with acquired foot deformities.
Which opioid analgesics are used in surgical practice for postoperative pain relief?
- Fentanyl is an opioid drug with minimal respiratory and hemodynamic depression, used among other things for patient-controlled analgesia.
- Trimeperidine is an opioid analgesic used intramuscularly on the first day after surgery and strictly according to indications when severe pain persists.
- Morphine is an opioid analgesic used in the early postoperative period and when NSAIDs are insufficiently effective.
- Tramadol is an opioid analgesic with equianalgesic dosages to other agonists.
What pulmonary complications can develop due to inadequate postoperative pain relief?
- Decreased cough reflex and respiratory depression are described as manifestations of postoperative pain syndrome.
- Pulmonary atelectasis refers to respiratory disorders of the early postoperative period; adequate pain relief is indicated in its prevention and treatment.
- Pneumonia refers to respiratory disorders of the early postoperative period; adequate pain relief is indicated in its prevention and treatment.
- Bronchitis refers to respiratory disorders of the early postoperative period; adequate pain relief is indicated in its prevention and treatment.
- Adequate pain relief allows the patient to effectively expectorate sputum, breathe deeply, and remain active, which serves as a prevention of postoperative complications.
What scales are used for the objective assessment of postoperative pain intensity?
- VAS (Visual Analog Scale) is a 10 cm uncalibrated line reflecting pain intensity in millimeters and possessing the highest sensitivity.
- Numerical Rating Scale is a scale with digital calibration from 0 to 10 points.
- VRS (Verbal Rating Scale) is a scale containing adjectives and/or digital designations from "no pain" to "excruciating".
- Faces Pain Scale for children is a tool for assessing pain intensity in children.
- Digital Pain Rating Scale is a numerical pain rating scale.
What are the principles of multimodal analgesia in the postoperative period?
- Joint use is the combined use of various analgesics with different mechanisms of action, analgesia technologies, and non-pharmacological methods.
- Nervous system action is the effect on the peripheral and/or central parts of the nervous system.
- Synergistic effect is the achievement of more effective pain relief through the combination of drugs.
- Basic therapy is the use of a combination of nonsteroidal anti-inflammatory drugs and paracetamol as the basis of treatment.
- Adjuvant enhancement — the addition of opioid analgesics, regional techniques, and other medications for moderate and severe pain.
Class and exam questions
How does postoperative pain affect respiratory function?
Pain causes shallow breathing and a reflex fear of coughing. This leads to respiratory depression, a decrease in the effectiveness of the cough reflex, and impaired clearance of bronchial secretions.
Why does severe pain syndrome lead to elevated blood pressure?
Pain-induced psychoemotional stress triggers a surge of catecholamines. They stimulate the cardiovascular system, causing persistent tachycardia and elevated blood pressure.
Which postoperative analgesia regimen is preferentially used in elderly patients?
In elderly patients, the combination of non-opioid analgesics with additional methods, such as continuous epidural anesthesia or percutaneous electrical analgesia, is most strongly indicated.
What is the main goal of postoperative pain relief?
The primary goal is to enable the patient to be active, take deep breaths, and effectively clear sputum by coughing. This is a key component in the prevention of postoperative complications.
What else to study on this topic
- Mechanisms of action of opioid analgesics and the safety profile of fentanyl
- Technique and monitoring for continuous epidural anesthesia
- Pathogenesis of psychoemotional stress during surgical interventions
- Physiotherapy methods: percutaneous electrical analgesia and acupuncture in surgery
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