Anesthesiology
-
Pharyngeal cooling decreases brain temperature by cooling carotid arteries. This study was designed to evaluate the principle of pharyngeal cooling in monkeys and humans. ⋯ Pharyngeal cooling rapidly and selectively decreased brain temperature in primates and tympanic temperature in humans and did not have adverse effects on return of spontaneous circulation, even when initiated during cardiac arrest in primates.
-
Nitrous oxide converts vitamin B12 to its nonmetabolically active form, inhibits methionine synthase, and results in an elevation of plasma total homocysteine (tHcy). The authors investigated the effect of nitrous oxide anesthesia on the plasma tHcy concentrations in children the morning after surgery and whether blood concentrations of folate and vitamins B12 and B6 were associated with any potential increase. ⋯ Exposure to ≥ 2 h nitrous oxide is associated with a small, albeit statistically significant, increase in postoperative plasma tHcy concentrations the morning after surgery in young children. The clinical significance of this increase is unknown.
-
The diagnosis of sympathetically maintained pain (SMP) is typically established by assessment of pain relief during local anesthetic blockade of the sympathetic ganglia that innervate the painful body part. To determine if systemic α-adrenergic blockade with phentolamine can be used to diagnose SMP, we compared the effects on pain of local anesthetic sympathetic ganglion blocks (LASB) and phentolamine blocks (PhB) in 20 patients with chronic pain and hyperalgesia that were suspected to be sympathetically maintained. The blocks were done inrandom order on separate days. ⋯ The pain relief achieved by LASB and PhB correlated closely (r = 0.84), and there was no significant difference in the maximum pain relief achieved with the two blocks (t = 0.19, P > 0.8). Nine patients experienced a greater than 50% relief of pain and hyperalgesia from both LASB and PhB and were considered to have a clinically significant component of SMP. We conclude that α-adrenergic blockade with intravenous phentolamine is a sensitive alternative test to identify patients with SMP.
-
Data can be collected for various purposes with anesthesia information management systems. The authors describe methods for using data acquired from an anesthesia information management system to assess intraoperative utilization of blood and blood components. ⋯ The use of data acquired from an anesthesia information management system allowed a detailed analysis of blood component utilization, which revealed significant variation among surgical services and surgical procedures, and among individual anesthesiologists and surgeons compared with their peers. Incorporating these methods of data acquisition and analysis into a blood management program could reduce unnecessary transfusions, an outcome that may increase patient safety and reduce costs.
-
Xenon is a general anesthetic with neuroprotective properties. Xenon inhibition at the glycine-binding site of the N-Methyl-D-aspartate (NMDA) receptor mediates xenon neuroprotection against ischemic injury in vitro. Here we identify specific amino acids important for xenon binding to the NMDA receptor, with the aim of finding silent mutations that eliminate xenon binding but leave normal receptor function intact. ⋯ These findings confirm xenon binds to the glycine site of the GluN1 subunit of the NMDA receptor and indicate that interactions between xenon and the aromatic ring of the phenylalanine 758 residue are important for xenon binding. Our most important finding is that we have identified two mutations, F758W and F758Y, that eliminate xenon binding to the NMDA receptor glycine site without changing the glycine affinity of the receptor or the binding of volatile anesthetics. The identification of these selective mutations will allow knock-in animals to be used to dissect the mechanism(s) of xenon's neuroprotective and anesthetic properties in vivo.