Pharmacology

Metaraminol use during spinal anaesthesia for caesarean section

Phenylephrine has recently displaced Ephedrine as the pressor of choice for spinal induced hypotension during Cesarean Section. However an older agent makes a comeback in this study, although it has remained popular in some countries.

Conclusions:Metaraminol appears superior to ephedrine for the prevention of feto-maternal complications.

Metaraminol is associated with better umbilical arterial pH values than phenylephrine.

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Anaesthesia and sedation in breastfeeding women

The Association of Anaesthetists has provided a draft copy open for comment on the topic of breastfeeding and anesthesia/sedation.

In general, the conclusion is that only tiny amounts of most agents are present in breast milk and feeding can be resumed after anesthesia once the mother is awake and lucid. The practice of “pump and dump” is largely unnecessary. However this draft document looks at all commonly used agents in anesthesia and sedation and evidence is in some cases limited, and some agents may pose some degree of risk, like Oxycodone.

Single doses of most analgesics pose little risk but caution is advised with repeated doses.

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Induction Technique Among Infants and Neonates Undergoing Pyloromyotomy

The decline is Succinylcholine use has been expedited by the arrival of Sugammadex. Succinylcholine is often still preferred where the risk of aspiration is deemed higher.

This study compared rapid sequence induction (RSI) with modified rapid sequence induction (mRSI) in infants.

The conclusion found mRSI acceptable practice: “In infants presenting for pyloromyotomy, anesthetic induction with mRSI compared with RSI was associated with significantly less hypoxemia without an observed increase in aspiration events. In addition, the need for multiple intubation attempts was a strong predictor of hypoxemia. The increased risk of hypoxemia associated with RSI and multiple intubation attempts was even more pronounced in neonatal patients.”

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International consensus statement on the use of uterotonic agents during caesarean section

This statement updates use of uterotonic agents. Traditionally Oxytocin has been used in higher then needed doses and this statement reiterates current expert opinion on the use of smaller titrated doses in most situations, especially in elective Cesarean.

They discuss the increasing use of Carbetocin as an alternative, which has the advantage of a longer half life thereby obviating the need for an infusion. Side effects are similar.

Second line agents are discussed also.

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Consensus Statement on Persistent Postoperative Opioid Use

This statement looked at the definition, incidence and risk factors for persistent postoperative opioid use and how it might be dealt with.

“Patient characteristics associated with an increased risk of persistent postoperative opioid use included preoperative opioid use, depression, substance use disorder, preoperative pain conditions, and smoking.”

They discuss in the free full text how health policy may help to curtail persistent opioid use.

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Mannitol in Critical Care

Mannitol has a long history of use to decrease intracranial pressure in neurosurgery and traumatic brain injury but it’s effect on long term outcome is still uncertain.

This free full text review – a meta-analysis and systematic review – surveys its history and usage. Its conclusion is essentially:

“Mannitol is effective in accomplishing short-term clinical goals, although hypertonic saline is associated with improved brain relaxation during craniotomy. Mannitol has a favorable safety profile although it can cause electrolyte abnormality and renal impairment. More research is needed to determine its impacts on long-term outcomes.”

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Music versus midazolam during preoperative nerve block placements

The essential conclusion in this study was the equivalence between music played through noise cancelling headphones and Midazolam.

While previous evidence has suggested the utility of music for awake patients, it should be noted that physician satisfaction was higher than patient satisfaction. And both judged communication to be more impaired in the music group.

Nonetheless sedation has gone s little out of fashion in both anesthesia and ICU with links to delirium in many studies in the elderly and substitution with music may be worth considering.

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Dexmedetomidine + Propofol for Colonoscopy?

Numerous adjuvants to Propofol have been used for colonoscopy sedation, such as Midazolam or more recently Ketamine or Lidocaine. This study supports Propofol as a sole agent.

Combining a low dose of dexmedetomidine with propofol decreased propofol consumption in adults having ambulatory colonoscopy, with no increase in sustained bradycardia. However, using only propofol for colonoscopy provided more stable hemodynamics, faster recovery from anesthesia, and faster attainment of discharge readiness, compared with using propofol–dexmedetomidine.

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Haloperidol and Long Term ICU Outcome

This study examined the use of prophylactic Haloperidol in ICU patients at high risk of delirium. While it is often a treatment agent used when non-pharmacological approaches to delirium fail, this study confirms that prophylactic use exerts no beneficial effect on long-term quality of life in ICU survivors.

The REDUCE study previously showed that neither does it reduce the incidence or duration of delirium.

“The factors age, medical, and trauma admission, baseline quality of life, risk for delirium, and the number of sedation-induced coma days are associated with the decline in long-term outcome parameters.”

And a major message is “Every additional day of sedation-induced coma is associated with further decline of long-term physical and mental function”.

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Risk factors for postoperative delirium in patients undergoing lower extremity joint arthroplasty

This large national cohort “identified various modifiable risk factors (including anesthesia type and pharmaceutical agents) for postoperative delirium, demonstrating possible prevention pathways.”

Benzodiazepines and gabapentinoids were associated with higher odds of delirium, whereas lower risk of delirium was associated with neuraxial vs. general anesthesia, use of NSAIDs and COX2 Inhibitors, and high vs low opioid use specifically in the over 65 year olds.

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