Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2010
Detection of carbon monoxide during routine anesthetics in infants and children.
Carbon monoxide (CO) can be produced in the anesthesia circuit when inhaled anesthetics are degraded by dried carbon dioxide absorbent and exhaled CO can potentially be rebreathed during low-flow anesthesia. Exposure to low concentrations of CO (12.5 ppm) can cause neurotoxicity in the developing brain and may lead to neurodevelopmental impairment. In this study, we aimed to quantify the amount of CO present within a circle system breathing circuit during general endotracheal anesthesia in infants and children with fresh strong metal alkali carbon dioxide absorbent and define the variables associated with the levels detected. ⋯ CO was detected routinely during general anesthesia in infants and children when FGF:(.)VE was <1. Peak CO levels measured in the anesthesia breathing circuit were in the range thought to impair the developing brain. Further study is required to identify the source of CO detected (CO produced by degradation of volatile anesthetic versus rebreathing CO from endogenous sources or both). However, these findings suggest that avoidance of low-flow anesthesia will prevent rebreathing of exhaled CO, and use of carbon dioxide absorbents that lack strong metal hydroxide could limit inspired CO if detection was attributable to degradation of volatile anesthetic.
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Anesthesia and analgesia · Mar 2010
Sensory testing of distal sural and posterior tibial nerves provides early prediction of surgical anesthesia after single-injection infragluteal-parabiceps sciatic nerve block.
Surgical anesthesia for reconstructive ankle surgery requires sensory and motor block of all the terminal nerve distributions of the sciatic nerve. In this prospective observational study, we investigated the value of sensory and motor testing of the foot, after local anesthetic injection, for predicting complete sciatic nerve blockade and the duration of testing required for identifying incomplete anesthesia. ⋯ Sural anesthesia assessed at the lateral heel and the lateral aspect of the foot and the fifth toe identified within 4 to 6 minutes demonstrated a similar posttest predictive value as anesthesia in the distributions of the posterior tibial and peroneal nerves or motor movement of the foot at later intervals. In addition, failure to achieve sural anesthesia within 10 minutes was predictive of block failure.
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Anesthesia and analgesia · Mar 2010
The diverse effects of vasopressors on the fetoplacental circulation of the dual perfused human placenta.
We studied the effects of 5 vasopressors on fetal arterial perfusion pressure (FAP) in vitro using the dual perfused, single isolated cotyledon, human placental model. ⋯ In the dual perfused, single isolated cotyledon, human placental model, exposure of the maternal circulation to ephedrine and phenylephrine caused an increase in FAP, whereas exposure to norepinephrine, epinephrine, and methoxamine did not. The pharmacodynamic mechanisms underlying these differences have yet to be explained. Thus, the clinical implications of the findings are as yet unclear.