Regional Anesthesia

Dural puncture epidural versus conventional epidural block

Dural Puncture Block has become an increasingly discussed technique in labor and delivery analgesia, whereby no spinal medication is given but the dural hole is thought to enhance spread and speed of onset.

This review found “a lack of clear evidence on either the benefits or the risks of the DPE technique, such that a recommendation for or against its routine use is premature. Two of the three studies showing a beneficial effect of DPE came from the same institution and replication of the findings by other groups is warranted.”

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Post Dural Puncture Headache Treatment

A new guideline from the Obstetric Anaesthetists Association underlines how little evidence is really available to guide management of post dural puncture headache. Epidural Blood Patch remains the best treatment but in general is more effective after 48 hours. Some relief occurs in up to 80%, and complete resolution of pain in about a third. It may need repeating. 20mL blood is suggested or less if back pain develops.

There is insufficient evidence on a whole host of suggested treatments – steroids, gabapentinoids, ACTH, caffeine, triptans, theophylline, neostigmine and atropine, acupuncture, various nerve blocks, and epidural crystalloid.

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Neuraxial Anesthesia-Delivery time interval

Traditionally one of the more critically identified time frames after spinal anesthesia for Cesarean is the uterine incision to delivery time, and this is confirmed in this study.

After neuraxial anesthesia, uterine hypoperfusion from hypotension and maternal obesity may compromise the fetus. This study shows a direct correlation between increasing delay before delivery and decreasing umbilical artery pH.

“Efforts to minimize predelivery time following spinal placement could reduce the frequency of unanticipated neonatal acidemia.”

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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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Phenylephrine vs. Norepinephrine in Cesarean

A growing interest in the use of small bolus Norepinephrine (Noradrenaline) for Cesarean hypotension is based on its presumed lesser tendency to cause bradycardia compared to Phenylephrine.

This small study compared the effects of 100 μg phenylephrine and 5 μg norepinephrine and found no difference in maternal bradycardia. The number of boluses needed was higher in the Phenylephrine group.

“However, in view of the lower umbilical artery pH when using noradrenaline, further research is warranted to study its placental transfer and fetal metabolic effects”.

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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Lung Resection, Anesthetic Technique and ICU Admission

This retrospective study examined Total Intravenous Anesthesia (TIVA), volatile inhalational anesthesia, and analgesic techniques of epidural or paravertebral block. Lung resection was the specific focus.

The aim was to investigate the influence of anaesthetic and analgesic technique on the need for unplanned postoperative intensive care admission – defined as the unplanned need for either tracheal intubation and mechanical ventilation or renal replacement therapy.

It was found that patients having TIVA or epidurals were less likely to have an unplanned admission to intensive care.

Mortality and length of stay was higher in those needing unplanned ICU admission.

The study discusses possible mechanisms for these findings but emphasizes that prospective randomized trials are needed to prove causation.

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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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Intermittent Lumbar Plexus Block vs. Continuous

A clear trend towards programmed intermittent bolus rather than continuous infusion has emerged in epidural analgesia in labor. Other regional analgesia pain blocks have found the same.

This study using lumber plexus block in total hip arthroplasty again finds intermittent rather than continuous infusion led to lower opioid rescue and more consistently maintained sensory block.

The regime was: continuous infusion group 6 mL/hour continuous infusion of levobupivacaine 0.125%, and intermittent infusion group 12 mL of levobupivacaine 0.125% bolus delivered every 2 hours.

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