British journal of anaesthesia
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Randomized Controlled Trial
Lidocaine use in ultrasound-guided femoral nerve block: what is the minimum effective anaesthetic concentration (MEAC90)?
This study aimed to estimate the minimum effective anaesthetic concentrations of lidocaine required to block the femoral nerve under ultrasound (US) guidance in 90% (MEAC90) of patients. ⋯ Perineural injection of 15 ml of lidocaine 0.93% w/v under US guidance could provide successful femoral nerve block in 90% of patients.
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It is unclear what factors affect the uptake of sevoflurane administered through the membrane oxygenator during cardiopulmonary bypass (CPB) and whether this can be monitored via the oxygenator exhaust gas. ⋯ The uptake of sevoflurane delivered via the membrane oxygenator during CPB seems to be affected by hypothermia, haemodilution, and changes in the oxygenator fresh gas supply flow. Measuring the concentration of sevoflurane in the exhaust from the oxygenator is not useful for monitoring sevoflurane administration during bypass.
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Randomized Controlled Trial
Influence of ketamine and morphine on descending pain modulation in chronic pain patients: a randomized placebo-controlled cross-over proof-of-concept study.
Descending inhibition of pain, part of the endogenous pain modulation system, is important for normal pain processing. Dysfunction is associated with various chronic pain states. Here, the effect of ketamine and morphine on descending inhibition is examined using the conditioned pain modulation (CPM) paradigm in chronic neuropathic pain patients. ⋯ The observed treatment effects in chronic pain patients suggest a role for CPM engagement in analgesic efficacy of ketamine, morphine, and placebo treatment.
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Exposure to general anaesthesia during critical stages of brain development results in long-lasting cognitive impairment. Co-administration of protective agents could minimize the detrimental effects of anaesthesia. Co-administration of R(+)pramipexole (PPX), a synthetic aminobenzothiazol derivative that restores mitochondrial integrity, prevents anaesthesia-induced mitochondrial and neuronal damage and prevents early development of cognitive impairment. Here, we determine the protective effects of PPX into late adulthood in male and female rats. ⋯ PPX provides long-lasting protection against cognitive impairment known to occur when very young animals are exposed to anaesthesia during the peak of brain development. Anaesthesia-induced cognitive impairment appears to be sex-specific with females being more vulnerable than males, suggesting that they could benefit more from early prevention.
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Measurement of the balance between nociception and anti-nociception during anaesthesia is challenging and not yet clinically established. The Surgical pleth index (SPI), derived from photoplethysmography, was proposed as a surrogate measure of nociception. Recently, the analgesia nociception index (ANI) derived by heart rate (HR) variability was developed. The aim of the present study was to challenge the ability of ANI compared with SPI to detect standardized noxious stimulation during propofol-remifentanil anaesthesia. ⋯ The two variables, ANI and SPI, enabled consistent reflection of stimulation during propofol-remifentanil anaesthesia. Nevertheless, ANI and SPI may improve detection but not prediction of a possible inadequate nociception-anti-nociception balance. Clinicaltrials.gov Identifier. NCT01522508.