Intravenous route
Oral route
Rectal route
Subcutaneous route
Topical
Antiepileptic
Ketamine
NSAIDs
Opioids
Antiepileptic
Antidepressants
Antihistamines
Anxiolytics
Cortisone
Hypnotics
Local anesthetics
NSAIDs
Opioids
Acetaminophen
Aspirin
Opioids
Phenothiazines
Local anesthetics
Opioids
Capsaicin
Cold
Hot
Lidocaine/prilocaine
Local anesthetics
Interventional
Treatment of pain with the use of local injections or invasive procedures
Consultation preoperatively with a specialist in pain therapy
Physical therapy
Biofeedback
Exercise
Hot/cold
Immobilization
Massage
TENS (transcutaneous electrical nerve stimulation)
Relaxation
7.2.2 Continuous Peripheral Blocks
In recent years, continuous peripheral blocks have been used successfully in the treatment of acute postoperative pain (Level A). After orthopedic surgery of the upper and lower limbs, clinical trials have shown that continuous peripheral blocks are as effective as continuous epidural block, and both are considerably more effective than parenteral opioids (Level A). Studies have shown a remarkable effectiveness of these techniques in reducing pain at rest and during movement, the consumption of opioid analgesics, and nausea and vomiting. This treatment has improved, especially in orthopedic surgery, functional recovery with adequate analgesia, and reduced side effects (Level A). Regional analgesia should also be used in critically ill patients to reduce the consumption of sedatives and opiates (Level C).
After major orthopedic surgery of the upper and lower limbs, clinical studies have shown that continuous peripheral blocks are as effective as continuous epidural and that both are greatly more effective than intravenous opioids or infiltration with local anesthetics (Level A).
Regional analgesia also should be used in critically ill patients to reduce the consumption of sedatives and opiates (Level C).
It has been shown that, in knee surgery, the adductor canal ultrasound-guided block, compared with continuous femoral block, ensures equal analgesia and lower incidence of quadriceps femur motor block, thus preventing accidental falls in the first postoperative days [4, 8]. Likewise, the role of continuous thoracic paravertebral block for breast and thoracic surgery has been reaffirmed as an alternative to continuous epidural and TAP (transversus abdominis plane) block (abdominal wall block with continuous infusion of local anesthetic).
7.2.3 Infusion Modality
Several studies have shown that PCRA (patient controlled regional anesthesia) is a more effective infusion baseline in postoperative pain control and allows a better mobilization of the patient (Level C).
It is recommended to avoid continuous infusion techniques with no flow control devices and to adopt a programmed registration system, including pain level, analgesia effectiveness, and side effects notation (Level A).
7.2.4 Patient Controlled Analgesia (PCA)
7.2.4.1 PCA Intravenous
The intravenous PCA is a method for the treatment of postoperative pain that allows the patient to self-administer the needed doses of analgesics. The intravenous PCA opioid guarantees better analgesia (with an average of 5 mm on a scale 0–100 mm for pain) and greater patient satisfaction than conventional treatments with parenteral opioids at fixed hours (Level A).
The intravenous opioid PCA, however, is not associated with a reduction in opioid consumption or reduced incidence of side effects related to opioids compared with conventional treatments with parenteral opioids (Level A). There is no evidence that a basal infusion can improve pain relief or quality of sleep, or reduce the number of doses required by IV PCA. Before starting treatment with PCA, a correct initial titration must be made to reach an adequate level of analgesia.
The incidence of side effects related to opioids, including respiratory depression, is the same for both the IV PCA and the intermittent administration of opioid analgesics (Level A). The risk factors for respiratory depression associated with IV PCA are divided into those associated with the patient (elderly, children, obesity, obstructive sleep apnea, respiratory failure) and those related to the technique:
mistakes made by the patient
errors made by operators (programming errors, accidental boluses during the syringe change, inappropriate prescription drug dose, inadequate dose interval).
7.2.5 Day Surgery
7.2.5.1 Anesthetic Approach (Level A)
Whenever possible, general anesthesia should be integrated with preemptive analgesia (acetaminophen/NSAIDs and/or peri-incisional local anesthetic infiltration).
Due to the expected vomiting/pain interactions, the use of nitrous oxide is not recommended. If indicated, peripheral nerve blocks are preferred over general anesthesia (Table 7.2).
Table 7.2
Security intervals between drug administration interfering with coagulation and execution of epidural block
ENF 4 h |
LMWH low doses 12 h |
LMWH high doses 24 h |
Fondaparinux 36 h |
Anti Vitamin K INR <1.5 |
Ticlopidine 10 days |
Clopidogrel 7 days |
Tirofiban 8–10 h |
Hirudin 8–10 h |
Abciximab 24–48 h |
Dabigatran Nc |
Rivaroxaban 18–22 h |
Apixaban 24 h |
7.2.5.2 Early and Late Postoperative Recovery: Analgesia at Discharge (Level D)
The hospital discharge letter must include pain assessment, postoperative drug provision plan, rescue dose commitment, and adverse events prevention suggestions. It is recommended to provide, both orally and in writing, information and clear and precise instructions on where and when prescribed drugs can be taken and how side effects can be controlled. These recommendations relate particularly to the need to clearly inform patients who are discharged with continuous perinervous infusion of local anesthetics, emphasizing the risks of loss of motor function and ambulation.
7.3 Specific Groups of Patients
7.3.1 Elderly Patients
In elderly patients (>65 years), the following is recommended:
use of a simple semantic scale (absent, mild, moderate, severe) to measure pain in collaborating patients;
use of neuro-behavioral parameter scales in uncooperative patients;
taking account of changes in pharmacokinetics and pharmacodynamics to avoid the risks involved in the choice of NSAIDs/coxibs;
reducing the minimum effective dose of opioids from 1/3 to 2/3;
use of methods of PCA is safe in elderly patients without cognitive deficits;
use of methods of epidural analgesia requires a reduction of the doses of local anesthetics and opioids;
ensure a level of analgesia aimed at early motor rehabilitation and a complete functional recovery plan.
7.3.2 Pediatric Patients
An appropriate analgesia plan must be considered over sedation alone. The most used drugs for the procedural analgosedation are nitrous oxide, associated or not to low doses of ketamine and midazolam. For minor procedures (venipuncture, stitches, etc.) the inhalation of nitrous oxide (50 %) and/or the use of topical local anesthetic can be considered an effective and safe procedure (Level A).
For procedures of moderate severity (lumbar puncture, aspiration of bone marrow) the inhalation of nitrous (50 %) and the use of topical or local anesthetic for injection is effective in most patients (Level A).
For other procedures (reduction of fracture), regional IV blocks with local anesthetic are effective in most of children, despite the potential complications and the high incidence of side effects. General anesthesia may be more appropriate in some groups of patients. Cognitive techniques, the presence of family members, behavioral interventions (Level C), and administration of sugar reduce behavioral responses in neonates and infants (Level B).
Paracetamol and NSAIDs are effective for pain with moderate intensity and reduce the opioid requirements after major surgery (Level A). Acetylsalicylic acid should be used with caution in children to reduce the potential risk of Reye’s syndrome. In addition, aspirin and NSAIDs increase the risk of postoperative bleeding (Level A). Severe side effects are rare in children above 6 months of age.
Opioids are effective and can be used safely in children of all ages. The initial opioid dose must be established according to weight and age and must be adjusted according to the individual response.
The mode of administration with PCA is very effective and safe; it can be used in children who are able to collaborate, typically 5 years and older.