Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2006
ReviewThe use of hypertonic saline for treating intracranial hypertension after traumatic brain injury.
The past decade has witnessed a resurgence of interest in the use of hypertonic saline for low-volume resuscitation after trauma. Preliminary studies suggested that benefits are limited to a subgroup of trauma patients with brain injury, but a recent study of prehospital administration of hypertonic saline to patients with traumatic brain injury failed to confirm a benefit. ⋯ There are few clinical studies in traumatic brain injury with patient survival as an end point. In this review, we examined the experimental and clinical knowledge of hypertonic saline as an osmotherapeutic agent in neurotrauma.
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Anesthesia and analgesia · Jun 2006
ReviewMorphine-6-glucuronide: morphine's successor for postoperative pain relief?
In searching for an analgesic with fewer side effects than morphine, examination of morphine's active metabolite, morphine-6-glucuronide (M6G), suggests that M6G is possibly such a drug. In contrast to morphine, M6G is not metabolized but excreted via the kidneys and exhibits enterohepatic cycling, as it is a substrate for multidrug resistance transporter proteins in the liver and intestines. M6G exhibits a delay in its analgesic effect (blood-effect site equilibration half-life 4-8 h), which is partly related to slow passage through the blood-brain barrier and distribution within the brain compartment. ⋯ At analgesic doses, M6G causes similar reduction of the ventilatory response to CO2 as an equianalgesic dose of morphine but significantly less depression of the hypoxic ventilatory response. Preliminary data indicate that M6G is associated less than morphine with nausea and vomiting, causing 50% and 75% less nausea in postoperative and experimental settings, respectively. Although the data from the literature are very promising, we believe that more studies are necessary before we may conclude that M6G is superior to morphine for postoperative analgesia.
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Knowledge of postoperative nausea and vomiting (PONV) risk factors allows anesthesiologists to optimize the use of prophylactic regimens. Modern PONV risk research began in the 1990s with publication of studies using logistic regression analysis to simultaneously identify multiple independent PONV predictors and publication of meta-analyses and systematic reviews. This literature shows that female gender post-puberty, nonsmoking status, history of PONV or motion sickness, childhood after infancy and younger adulthood, increasing duration of surgery, and use of volatile anesthetics, nitrous oxide, large-dose neostigmine, or intraoperative or postoperative opioids are well established PONV risk factors. ⋯ Early-phase menstruation, obesity and lack of supplemental oxygen are disproved risk factors. Current risk scoring systems have approximately 55%-80% accuracy in predicting which patient groups will suffer PONV. Further research examining genetic and under-investigated clinical patient characteristics as potential risk factors, and involving outpatients and children, should improve predictive systems.