Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1996
Comparative StudyHydroxyethyl starch solution attenuates blood-brain barrier disruption caused by intracarotid injection of hyperosmolar mannitol in rats.
This study was performed to investigate whether a fraction of hydroxyethyl starch macromolecules, prepared from pentastarch and known as "Hes-Pz," with molecular weights of 100,000-1,000,000, protects against blood-brain barrier (BBB) disruption due to intracarotid injection of hyperosmolar mannitol. Rats were anesthetized with isoflurane, and retrograde catheterization of a unilateral eternal carotid artery was performed. Except for the Control group (n = 8), hemodilution was performed using lactated Ringer's solution LR group, n = 7), 6% hetastarch (HES group, n = 7), or 6% HES-Pz (HES-Pz group, n = 8) to reduce the hematocrit to about 23%. ⋯ Ki was similar in the CC in all four groups. The Ki in the IC was significantly lower in the HES-Pz(6.4 +/- 3.5 microL.g-1.min-1) than in the Control, HES, or LR group (16.3 +/- 6.1, 19.0 +/- 12.9, 17.9 +/- 10.8 microL.g-1.min-1, respectively). Our data suggest that HES-Pz significantly attenuates disruption of the BBB caused by an injection of hyperosmolar mannitol.
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Anesthesia and analgesia · Aug 1996
Comparative StudyClinical evaluation of a prototype motion artifact resistant pulse oximeter in the recovery room.
The frequency and nature of spurious pulse oximetry readings were compared using both a conventional pulse oximeter (CPO) and a prototype Masimo signal extraction technology pulse oximeter (Masimo SET). At a university hospital, 50 ASA physical status I-IV adult patients who underwent general or spinal-epidural anesthesia were selected from a group of 250 patients on the basis of high-alarm generation with routine postoperative pulse oximetry. Pulse oximetry data were recorded simultaneously from both devices with a computer. ⋯ The prototype Masimo SET device alarm frequency was once every 30 min, and 59% of these were considered false. During arm motion with 15 patients, the CPO device produced spurious signals on 54 occasions compared with five for the prototype Masimo SET. The incidence of artifactual pulse oximetry events during patient motion appear to be substantially reduced with the prototype Masimo SET device, relative to a CPO device.
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Anesthesia and analgesia · Aug 1996
Heparin neutralization with methylene blue, hexadimethrine, or vancomycin after cardiopulmonary bypass.
There are no clinically available alternatives for reversing heparin in protamine-allergic patients. This study examined the ability of methylene blue, hexadimethrine, and vancomycin to reverse circulating heparin so that these compounds can be carefully examined in future placebo-controlled studies in humans. Heparin activity in blood obtained from extracorporeal circuits was reversed by adding protamine (13.5, 27.0, 81.1, 135.1, and 270.3 micrograms/mL), methylene blue (13.5, 27.0, 135.1, 202.7, 270.3, 337.8, 405.4, 473.0, 540.5, and 810.8 micrograms/mL), hexadimethrine (6.8, 13.5, 20.3, 27.0, 81.1, and 135.1 micrograms/mL), or vancomycin (13.5, 27.0, 135.1, 270.3, 540.5, and 810.8 micrograms/mL), and activated clotting times (ACTs) were measured with kaolin (n = 18). ⋯ Heparin concentrations were 3.3 +/- 0.3 U/mL with ACT values of 485 +/- 97 s. The ACT at a protamine concentration of 81.1 micrograms/mL and at hexadimethrine concentrations of 81.1 and 135.1 micrograms/mL was not statistically different from heparinase-ACT; however, methylene blue or vancomycin did not reverse the anticoagulation at any concentrations. Hexadimethrine can reverse heparin-induced anticoagulation after cardiopulmonary bypass as well as protamine, although methylene blue or vancomycin did not neutralize heparin in vitro.