Anesthesiology
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Oliguria is common in critically ill patients and may result from prerenal, renal, and postrenal causes. Oliguria also frequently develops in patients with normal concentrations of blood urea nitrogen and creatinine. Most of these patients do not develop renal failure. ⋯ The hypovolemic patients increased their urine output from 17 +/- 2 ml/h to greater than 0.5 ml.kg-1.h-1 following a 500-ml bolus of normal saline. The normovolemic oliguric patients remained oliguric following the saline bolus (13 +/- 2 to 19 +/- 3 ml/h). The authors conclude that oliguria is common in critically ill patients and results from renal hypoperfusion and ADH excess.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of 0.5% ropivacaine and 0.5% bupivacaine for epidural anesthesia in patients undergoing lower-extremity surgery.
Ropivacaine is an amide local anesthetic structurally related to, but appearing less cardiotoxic, than bupivacaine. The authors' investigation was designed in a randomized, double-blind fashion to compare the clinical effectiveness of ropivacaine and bupivacaine in patients undergoing lower-extremity surgery. Forty-five patients were randomized to receive 20 ml of 0.5% ropivacaine or bupivacaine. ⋯ Cardiovascular changes, incidence of tourniquet pain, and the amounts of supplemental medications necessary were also similar between groups. The authors found 0.5% ropivacaine and bupivacaine to be clinically similar in both sensory- and motor-blocking characteristics, with the exception that bupivacaine produced a blockade of slightly longer duration. Because ropivacaine is reported to be less cardiotoxic than bupivacaine in animal studies, the similarity of clinical epidural anesthesia may make ropivacaine the preferred agent.
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The preoperative fast is often an unpleasant preoperative experience that might be alleviated by allowing children to drink clear liquids. The authors compared gastric fluid volume and pH in two groups of children, one of whom was permitted clear liquids until 2 h before surgery (study group) and the other followed routine preoperative fasting orders (control group). The study group was not limited in the quantity of clear liquid allowed with the exception that the last intake prior to surgery was limited to 8 ounces. ⋯ Of the study patients, 48% had a measured gastric fluid volume greater than or equal to 0.4 ml/kg compared with 58% of the control patients (P = 0.77). Eighty three patients had sufficient gastric fluid for pH determination; of these 34/35 (97%) in the study group and 44/48 (92%) in the control group had a gastric fluid pH less than or equal to 2.5. Using a linear analog scale parents rated the children in the study group to be less irritable (P less than 0.001) and to have had a better overall preoperative experience (P less than 0.01) compared with the control patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Labor analgesia with epidural bupivacaine plus fentanyl: enhancement with epinephrine and inhibition with 2-chloroprocaine.
Epidural injection of drug combinations may decrease toxicity by decreasing the dose of each component, but may also result in detrimental drug interactions. In this study interactions among bupivaciane, fentanyl, epinephrine, 2-chloroprocaine, and lidocaine for epidural analgesia during labor were examined. In part 1 of the study, healthy parturients received in a random manner either 10 ml of 0.25% bupivacaine with 5 micrograms/ml fentanyl (n = 50), or 10 ml of this combination with 3.33 micrograms/ml freshly added epinephrine (n = 50). ⋯ The lidocaine test dose group had a greater duration of analgesia than the 2-chloroprocaine test dose group (median duration of 164 vs. 91 min, P less than 0.05). The authors conclude that the addition of epinephrine 3.33 micrograms/ml significantly increases the duration of analgesia obtained from 0.25% bupivacaine with 5 micrograms/ml fentanyl. However, prior injection of 2-chloroprocaine, but not lidocaine, significantly decreases the duration of analgesia achieved with this BFE mixture.
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A questionnaire inquiring about existing and desirable work and rest patterns appeared in a newsletter mailed to about 22,000 anesthesiologists and anesthesiology residents and 24,000 nurse anesthetists (CRNA). Almost 3,000 anonymous replies were received and analyzed. Respondents reported mean work weeks of 47.5 h (CRNA) to 69.8 h (residents), longest continuous period of administering anesthesia without a break of 6.6 h (CRNA) to 7.7 h (residents), and longest period of administering anesthesia with or without breaks of 14.1 h (CRNA) to 20 h (resident). ⋯ The majority of respondents recalled having made errors in the administration of anesthesia that they attributed to fatigue. These results may not be representative of work patterns or attitudes among American anesthesia providers because of the small sample size and the resultant potential for bias. Yet, the subject deserves attention and further study because fatigue can affect professional performance, ability to learn, and family life.