Pain

Tramadol and Persistent Opioid Use

Faced with the opioid epidemic, many have turned to postoperative use of Tramadol in the belief it has less misuse potential.

This observational study finds however that: “People receiving tramadol alone after surgery had similar to somewhat higher risks of prolonged opioid use compared with those receiving other short acting opioids”.

They advocate reclassifying Tramadol and urge caution in its prescription.

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Opioid Sparing in Pediatric Adenotonsillectomy

This QI project identified an opioid sparing anesthesia approach for pediatric tonsillectomy and adenotonsillectomy that moved away from morphine and acetaminophen, though Dexmedetomidine plus Ibuprofen, and finally on to the most effective regime consisting of Dexmedetomidine plus Ketorolac.

The study highlights both the move away from opioid based anesthesia as well as the increasing use of Intraoperative Dexmedetomidine.

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Intraoperative Methadone

Methadone assisted treatment of substance use disorders is well known but its potential for perioperative analgesia is under appreciated.

This review (full text for ASA members or subscription) may be helpful to introduce it as a long lasting intravenous agent given at the beginning of surgery. Common doses are 0.1 – 0.3mg/kg or a single 20mg dose with 3 – 5mg in PACU q 20mins. Analgesia is generally quite prolonged for 24 hours or more, and most of the evidence provided here does not show a higher rate of respiratory depression.

Caution is advised in the elderly or morbidly obese or those with cardiovascular co-morbidities. Further studies are needed on its potential adverse effects on QT prolongation or serotonin syndrome, effects on chronic pain, use in ambulatory surgery and in enhanced recovery protocols.

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Dexamethasone IV and Spinal Anesthesia

A systematic literature search followed by conventional meta‐analysis examined the effects of intravenous Dexamethasone during Spinal Anesthesia.

While its effects on nausea and vomiting are well known, this study found a high level of evidence that intravenous dexamethasone improves postoperative analgesia after spinal anaesthesia.

Dexamethasone use was associated with a significant reduction in 24‐h morphine consumption and times to first analgesia request was prolonged by 86 mins.

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Paravertebral Block

Many situations where epidurals were previously employed now use techniques such as paravertebral block.

This free full text review provides an excellent brief survey of the anatomy, and both older landmark-based and current ultrasound-guided techniques, uses in thoracic/abdominal/breast surgeries, and complications.

Also discussed are the so-called “paravertebral by proxy” blocks that indirectly spread there – erector spinae, midpoint transverse process, retro-laminar, and intercostal paraspinal blocks. These may become preferred approaches in less specialized hands where injury to pleura is likely to be less.

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Morphine vs. Hydromorphone in Day Surgery

This study objective was to compare morphine with hydromorphone for achieving satisfactory analgesia with minimal emesis in ambulatory surgery.

There were no differences in the side-effects of severe itching, respiratory depression, or sedation. Patient satisfaction, discharge times, and post-discharge outcomes, including pain and nausea/vomiting over 24 h, were also comparable.

It is believed by some that Hydromorphone has more euphoric effects that could encourage substance misuse.

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Opioid Dose Variability and Opioid Overdose

This study on those on long term opioid therapy found high variability in opioid dose was associated with a greater than 3-fold increased risk of opioid overdose even after controlling for dose.

This occurred even on low dose opioids. Several mechanisms are postulated, including tapering leading to withdrawal effects that precipitated recommencing higher doses, seeking other opioid prescriptions or sources etc.

Individuals with sustained opioid therapy discontinuation (defined as 3 continuous months with 0 mg of morphine equivalents before the index date) were 51% less likely to have experienced an overdose than individuals who had not discontinued opioid therapy

The authors warn that physicians should consider the risks that may be associated with dose variability when designing and implementing new policies to reduce opioid prescribing.

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Pediatric Temperament and Postoperative Pain

The influence of psychological, psychiatric and emotional factors on pain postoperatively has been well described. Recent studies have shown the negative effects of anxiety, depression, sleep disturbance, and even parental anxiety on postoperative pain in adults as well as children.

This study shows “preoperative temperament characteristics may differentially influence pediatric post‐operative pain experience in children. Specifically, children with high levels of positive and negative emotionality may exhibit more post‐surgical pain behaviors”.

The novel approach looked at broader temperament analysis; positive excitability clusters as well as the more well known negative attitudes are a factor to consider for pain prediction.

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Full text early view

Substance use disorders in pregnancy

The results of a joint workshop provide guidance on all aspects of substance use in pregnancy. Issues discussed in the full free text include screening tests, biologic tests, management of pain in labor and after Cesarean, pain after discharge, and approaches to medication assisted therapy (Methadone and Buprenorphine are standards of care), and organizational issues to optimize care. Discussion around breast feeding and the common neonatal opioid withdrawal syndrome (NOWS) occurs.

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Rib Fracture Analgesia

Rib fractures cause significant impairment of respiratory function and are often accompanied by severe pain. Two studies add to our knowledge.

The first used ultrasound guided paravertebral block. While they couldn’t definitely prove any mortality benefit, they found it safe, effective and with low complication rate.

The second used potentially easier Erector Spinae plane blocks, which were associated with improved inspiratory capacity and analgesic outcomes following rib fracture, without haemodynamic instability. Opioid consumption was not reduced however.

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