Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2004
The volume kinetics of acetated Ringer's solution during laparoscopic cholecystectomy.
We studied the distribution and elimination of an IV infusion of 20 mL/kg of acetated Ringer's solution (approximately 1500 mL) over 60 min in 12 women undergoing laparoscopic cholecystectomy. A plasma dilution of 4.2% developed during the induction of general anesthesia, even though fluid was withheld. The additional plasma dilution induced by the subsequent volume expansion was slightly larger than expected from previous volunteer experiments and averaged 18%. ⋯ These data represent a half-life of the fluid in the patients that is 17 times longer (median, 4.5 h) than the half-life of the plasma dilution (16 min), indicating a strong tendency to the formation of peripheral edema. A nomogram based on the kinetic variables suggests that infusion rates should be relatively rapid early on during surgery but slower later. This strategy creates a constant plasma dilution at any desired level without causing undue peripheral accumulation of fluid.
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Anesthesia and analgesia · Dec 2004
Apoptosis is not enhanced in primary mixed neuronal/glial cultures protected by isoflurane against N-methyl-D-aspartate excitotoxicity.
Volatile anesthetics reduce acute excitotoxic cell death in primary neuronal/glial cultures. We hypothesized that cells protected by isoflurane against N-methyl-d-aspartate (NMDA)-induced necrosis would instead become apoptotic. Primary mixed neuronal/glial cultures prepared from fetal rat brain were exposed to dissolved isoflurane (0 mM, 0.4 mM [1.8 minimum alveolar anesthetic concentration], or 1.6 mM [7 minimum alveolar anesthetic concentration]) and NMDA (0 or 100 microM) at 37 degrees C for 30 min. ⋯ At 48 h, no evidence was found to indicate that cells protected by isoflurane had become apoptotic or apoptotic-like. However, cells protected by dizocilpine against necrosis showed evidence of caspase-3-mediated apoptosis. These in vitro data do not support the hypothesis that isoflurane protection against acute excitotoxic necrosis results in apoptosis.
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Anesthesia and analgesia · Dec 2004
Randomized Controlled Trial Comparative Study Clinical TrialEmergence and recovery characteristics of desflurane versus sevoflurane in morbidly obese adult surgical patients: a prospective, randomized study.
We compared postoperative recovery after desflurane (n = 25) versus sevoflurane (n = 25) anesthesia in morbidly obese adults (body mass index >/=35) who underwent gastrointestinal bypass surgery via an open laparotomy. After premedication with midazolam and metoclopramide 1 h before surgery, epidural catheter placement, induction of anesthesia with fentanyl and propofol, and tracheal intubation facilitated with succinylcholine, anesthesia was maintained with age-adjusted 1 minimum alveolar concentration (MAC) desflurane or sevoflurane. Fentanyl IV, morphine or local anesthetics epidurally, and vasoactive drugs as needed were used to maintain arterial blood pressure at +/-20% of baseline value and to keep bispectral index of the electroencephalogram values between 40 to 60 U. ⋯ On admission to PACU, patients given desflurane had higher oxygen saturations (97.0% +/- 2.4%) than patients given sevoflurane (94.8% +/- 4.4%, P = 0.035). Overall, the incidence of postoperative nausea and vomiting and the use of antiemetics did not differ between the two anesthetic groups. We conclude that morbidly obese adult patients who underwent major abdominal surgery in a prospective, randomized study awoke significantly faster after desflurane than after sevoflurane anesthesia and the patients anesthetized with desflurane had higher oxygen saturation on entry to the PACU.
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Anesthesia and analgesia · Dec 2004
Preoperative anxiety and emergence delirium and postoperative maladaptive behaviors.
Based on previous studies, we hypothesized that the clinical phenomena of preoperative anxiety, emergence delirium, and postoperative maladaptive behavioral changes were closely related. We examined this issue using data obtained by our laboratory over the past 6 years. Only children who underwent surgery and general anesthesia using sevoflurane/O(2)/N(2)O and who did not receive midazolam were recruited. ⋯ The odds ratio of having new-onset postoperative maladaptive behavior changes was 1.43 for children with marked emergence status as compared with children with no symptoms of emergence delirium. A 10-point increase in state anxiety scores led to a 12.5% increase in the odds that the child would have a new-onset maladaptive behavioral change after the surgery. This finding is highly significant to practicing clinicians, who can now predict the development of adverse postoperative phenomena, such as emergence delirium and postoperative behavioral changes, based on levels of preoperative anxiety.
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Anesthesia and analgesia · Dec 2004
Comparative StudyThe mechanical properties of continuous spinal small-bore catheters.
Continuous spinal anesthesia (CSA) has a nearly 100-yr history. In situations of difficult removal of a CSA small-bore catheter, mechanical properties of the different catheters might be important, because breakage could occur. We compared 5 different CSA small-bore catheters, 22- to 28-gauge from 3 manufacturers, for tensile strength, tensile stress, distension, and yield strength. ⋯ The material characteristics of different CSA small-bore catheters for maximal tensile strength were: 22-gauge = 29.56 +/- 1.56 (mean +/- sd) Newton (N), 24-gauge = 16.77 +/- 1.61 N, 25-gauge = 9.20 +/- 0.48 N, 27-gauge = 4.61 +/- 0.25 N, 28-gauge = 5.07 +/- 0.59 N at room temperature. A strong correlation between maximal tensile strength and the outer diameter (r = 0.957, P < 0.001) and maximal tensile strength and the wall thickness (r = 0.9, P < 0.001) was observed. Although extrapolation from experimental studies to clinical routine should be made with care, our data suggest that catheters with higher-strength characteristics may reduce the risk of catheter breakage in patients, although clinical correlations are lacking.