Articles: anesthesia.
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Complexity of neuronal firing patterns may serve as an indicator of sensory information processing across different states of consciousness. Recent studies have shown that spontaneous changes in brain states can occur during general anesthesia, which may influence neuronal complexity and the state of consciousness. In this study, we investigated how the firing patterns of cortical neurons, both at rest and during visual stimulation, are affected by spontaneously changing brain states under varying levels of anesthesia. ⋯ However, this was contradicted by the observation of low neuronal complexity in both spontaneous and stimulus-related spike activity, which more closely aligns with unconsciousness. Our findings reveal that transient neuronal states with distinct spiking patterns can emerge in visual cortex at constant anesthetic concentrations. The reduced complexity in states associated with deep anesthesia likely indicates a disruption of conscious sensory information processing.
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Review Practice Guideline
Intrathecal catheter placement after inadvertent dural puncture in the obstetric population: management for labour and operative delivery. Guidelines from the Obstetric Anaesthetists' Association.
Recommendations:
- An intrathecal catheter may be inserted for the provision of analgesia and anaesthesia following inadvertent dural puncture during attempted epidural catheter placement. This decision must be made with consideration of potential risks and benefits (Grade C, moderate level of certainty).
- Whether using intermittent boluses or a continuous infusion technique, use the same local anaesthetic solution throughout labour (Grade I, low level of certainty).
- Maternal blood pressure should be checked every 5 min for 15 min following the first dose, and after every subsequent bolus given via an intrathecal catheter (Grade A, high level of certainty).
- As with epidural analgesia, sensory and motor block should be checked every hour during intrathecal catheter analgesia (Grade B, moderate level of certainty).
- Fetal heart rate should be continuously monitored during intrathecal analgesia (Grade B, moderate level of certainty).
- Top-ups of local anaesthetic for caesarean delivery should be given incrementally, with each bolus limited to 2.5 mg bupivacaine (or equivalent) (Grade I, low level of certainty).
- Extension of labour analgesia for caesarean delivery via an intrathecal catheter should be performed in an operating theatre (Grade B, moderate level of certainty).
- Non-invasive blood pressure, ECG and oxygen saturations should be monitored throughout the duration of intrathecal anaesthesia (Grade A, high level of certainty).
- All departments should have clear guidelines for the management of intrathecal catheters in labour and for delivery. These should highlight key risks, monitoring protocols and other safety measures (Grade A, low level of certainty).
- Only anaesthetists should administer top-ups through an intrathecal catheter, and connect, disconnect or reconnect the catheter and tubing (Grade A, low level of certainty).
- Anaesthetists should account for the dead space of the intrathecal catheter and filter when administering top-ups in labour or for operative delivery (Grade B, low level of certainty).
- An intrathecal catheter should be clearly labelled adjacent to the filter and on the front of any infusion pump (Grade A, low level of certainty).
- The multidisciplinary team (including any non-resident staff who may be called to attend the patient during labour or delivery), must be made aware of the intrathecal catheter through both verbal and written communication, including at every handover (Grade A, low level of certainty).
- Intrathecal catheters should be removed at the earliest opportunity following delivery to reduce the risk of accidental overdose and infectious complications (Grade B, low level of certainty).
- When patients who experience inadvertent dural puncture, with or without intrathecal catheter insertion, are discharged from hospital, follow-up should be in line with established guidance and include written information on headaches, ‘red flag’ symptoms, hospital contact information and communication with primary care (Grade B, low level of certainty).
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Reports are limited regarding supraglottic airway (SGA) usage in children in the prone position. This study aimed to compare the clinical performance of the Ambu®AuraGain™, a 2nd generation SGA, in children undergoing surgery in the prone and supine positions. We hypothesized that oropharyngeal leak pressure (OLP) in the prone position would not be inferior to that in the supine position. ⋯ OLP when using AuraGain in the prone position in children was not inferior to that in the supine position. This suggests that the AuraGain may be an effective option for children undergoing short surgical procedures in the prone position.
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Editorial Review
The safety of nitrous oxide: glass half-full or half-empty?
A systematic review of clinical trials confirms that including nitrous oxide in the gas mixture for general anaesthesia has minor short-term benefits and does not impact most patient safety outcomes. However, no risk-benefit analysis of nitrous oxide should ignore its known environmental effects. If continued nitrous oxide use is supported, strategies to minimise and monitor the contribution of medical nitrous oxide to global warming are vital.