Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2013
The effect of lipid emulsion on intracellular bupivacaine as a mechanism of lipid resuscitation: an electrophysiological study using voltage-gated proton channels.
Lipid resuscitation has become a standard treatment for local anesthetic (LA) systemic toxicity, but its mechanisms remain to be fully elucidated. Although the partitioning effect is one of the proposed mechanisms, it is difficult to evaluate its impact independently from several other mechanisms or to examine the intracellular concentration of a LA, which is primarily responsible for LA systemic toxicity. We recently reported that LAs as weak bases reduced voltage-gated proton currents by increasing intracellular pH, which could be estimated from the reversal potentials of the channels (Vrev). Using this characteristic, we examined the partitioning effect in detail and showed its impact on lipid resuscitation. ⋯ Here we quantitatively evaluated for the first time the partitioning effect of lipid emulsion therapy on the intracellular concentration of bupivacaine in real-time settings by analyzing behaviors of voltage-gated proton channels. Our results suggested that lipid emulsion markedly reduced the intracellular concentration of bupivacaine, which was mostly due to the partitioning effect. This could contribute to our understanding of the mechanisms underlying lipid resuscitation, especially the importance of the partitioning effect.
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Anesthesia and analgesia · Dec 2013
Lack of utility of a decision support system to mitigate delays in admission from the operating room to the postanesthesia care unit.
When the phase I postanesthesia care unit (PACU) is at capacity, completed cases need to be held in the operating room (OR), causing a "PACU delay." Statistical methods based on historical data can optimize PACU staffing to achieve the least possible labor cost at a given service level. A decision support process to alert PACU charge nurses that the PACU is at or near maximum census might be effective in lessening the incidence of delays and reducing over-utilized OR time, but only if alerts are timely (i.e., neither too late nor too early to act upon) and the PACU slot can be cleared quickly. We evaluated the maximum potential benefit of such a system, using assumptions deliberately biased toward showing utility. ⋯ Despite multiple biases that favored effectiveness, the maximum potential benefit of a decision support system to mitigate PACU delays on the day on the surgery was below the 70% minimum threshold for utility of automated decision support messages, previously established via meta-analysis. Neither reduction in PACU delays nor reassigning promised PACU slots based on reducing over-utilized OR time were realized sufficiently to warrant further development of the system. Based on these results, the only evidence-based method of reducing PACU delays is to adjust PACU staffing and staff scheduling using computational algorithms to match the historical workload (e.g., as developed in 2001).
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Anesthesia and analgesia · Dec 2013
Case ReportsA patient who received 191 spinal anesthetics over 5 years without evidence of neurologic complications by examination or magnetic resonance imaging.
We present the case of a 50-year-old man who suffered a crush injury to his right lower extremity in 2002 and received 191 spinal anesthetics to date with no identifiable neurologic complications by physical examination or imaging. He has undergone >300 operations at our institution related to recurrent infection and wound breakdown, including multiple amputations and debridements with 146 of these occurring in a span of 36 months. ⋯ There was no evidence of intrathecal scar tissue, adhesions, neuroma formation, or other changes that could be attributed to repeated lumbar puncture. Although uneventful in our single patient, safety with respect to the development of transient or permanent neurologic complications, infections, or subclinical pathology identified by imaging cannot be broadly extrapolated to repeat lumbar punctures.
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Anesthesia and analgesia · Dec 2013
Neonatal Exposure to Sevoflurane Causes Significant Suppression of Hippocampal Long-Term Potentiation in Postgrowth Rats.
The inhaled anesthetic sevoflurane is commonly used for neonates in the clinical setting. Recent studies have indicated that exposure of neonatal rodents to sevoflurane causes acute widespread neurodegeneration and long-lasting neurocognitive dysfunction. Although acute toxic effects of sevoflurane on cellular viability in the hippocampus have been reported in some studies, little is known about the effects of neonatal sevoflurane exposure on long-term hippocampal synaptic plasticity, which has been implicated in the processes of learning and memory formation. Our study is the first to examine the long-term electrophysiological impact of neonatal exposure to a clinically relevant concentration of sevoflurane. ⋯ Our present findings indicate that neonatal exposure to sevoflurane at a higher concentration can cause alterations in the hippocampal synaptic plasticity that persists into adulthood.
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Anesthesia and analgesia · Dec 2013
Increased mean time from end of surgery to operating room exit in a historical cohort of cases with prolonged time to extubation.
Prolonged time to extubation has been defined as the occurrence of a ≥ 15-minute interval from the end of surgery to removal of the tracheal tube. We quantified the increases in the mean times from end of surgery to exit from the OR associated with prolonged extubations and tested whether the increases were economically important (≥ 5 minutes). ⋯ We recommend that anesthesia providers document the times of extubations and monitor the incidence of prolonged extubations as an economic measure. This would be especially important for providers at facilities with many ORs that have at least 8 hours of cases and turnovers.