Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Effect of oral liquids and ranitidine on gastric fluid volume and pH in children undergoing outpatient surgery.
Eighty-eight children (mean age 5.6 yr, range 1-14 yr) about to undergo elective outpatient surgery were randomly assigned to four groups. All children were given phenolsulfonphthalein (PSP) orally 2-3 h before the scheduled time of surgery as a marker dye to assess gastric emptying. Immediately after receiving PSP they were given: group A--liquids, up to 5 ml/kg + placebo (glucose water 0.2 ml/kg); group B--liquids, up to 5 ml/kg + ranitidine 2 mg/kg in glucose water 0.2 ml/kg; group C--placebo only; group D--ranitidine only. ⋯ PSP could not be detected in the gastric samples from children in whom the ingestion-sampling interval was more than 2.25 h. In comparison with prolonged starvation, administration of oral liquids without ranitidine 2-3 h preoperatively did not produce a significant increase in mean volume of gastric aspirate, and there was no increase in the number of patients with gastric aspirate greater than 0.4 ml/kg. Administration of ranitidine with or without fluids resulted in a decrease in both volume and acidity of gastric contents.
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Comparative Study Clinical Trial Controlled Clinical Trial
Mivacurium-induced neuromuscular blockade following single bolus doses and with continuous infusion during either balanced or enflurane anesthesia.
Mivacurium chloride (BW B1090U) was administered to 72 patients during their elective surgery. The eight groups (nine subjects per cell) in the 2 x 2 x 2 study design differed in three factors: the size of the mivacurium bolus dose administered, whether or not this dose was followed by an infusion of mivacurium, and in the technique used for the maintenance of anesthesia. Four groups received a single bolus dose of mivacurium, 0.15 mg/kg, and the remaining four groups received mivacurium, 0.25 mg/kg, administered iv in 15 s. ⋯ Four groups, again two at each bolus dose, subsequently received an infusion of mivacurium, adjusted to depress the twitch response by approximately 95%. Infusion rates averaged 6.0 micrograms.kg-1.min-1 in the groups receiving balanced anesthesia and 4.2 micrograms.kg-1.min-1 for those receiving enflurane anesthesia. Recovery following administration by infusion was slower than that observed following a bolus dose of mivacurium, 0.15 mg/kg but did not differ between the anesthetic groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Perioperative pulmonary function in acute respiratory failure: effect of ventilator type and gas mixture.
Whether maintaining pulmonary nitrogenation and/or a stable ventilatory pattern during surgery would minimize changes in perioperative pulmonary function in two groups of patients with acute respiratory failure (ARF) whose lungs were being mechanically ventilated was examined. Group 1 (n = 39 cases) (inspired oxygen fraction [FIO2] less than or equal to 0.5, minute ventilation less than or equal to 15 l/min, peak inspiratory pressure less than or equal to 50 cmH2O, positive end-expiratory pressure [PEEP] less than or equal to 10 cmH2O) were assigned randomly to one of four intraoperative ventilator-gas mixture (FIO2 approximately 0.5) combinations: 1) Siemens 900C ventilator, N2/O2; 2) Siemens 900C ventilator, N2O/O2; 3) Ohio anesthesia ventilator, N2/O2; or 4) Ohio anesthesia ventilator, N2O/O2. Group 2 (n = 15 cases) (ventilatory requirements exceeding any of those in Group 1) had their lungs ventilated intraoperatively with the Siemens 900C ventilator and a gas mixture determined by their anesthesiologist (FIO2 approximately 0.6-1.0). ⋯ In patients whose lungs were ventilated with the Ohio N2/O2 combination, PaO2/FIO2 decreased significantly from 270 +/- 86 mmHg preoperatively to 174 +/- 74 mmHg intraoperatively. These variables did not change significantly in patients ventilated with the Siemens ventilator (groups 1 and 2). Pulmonary oxygen gas exchange returned to preoperative values by the first hour postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Pharmacokinetics and dynamics of intravenous, intrathecal, and epidural clonidine in sheep.
Epidural clonidine administration produces analgesia by a spinal action but may produce hemodynamic depression by activating other central or peripheral alpha 2-adrenoceptors. To determine clonidine's distribution and cardiorespiratory effects 300 micrograms clonidine was injected epidurally, intrathecally, and intravenously in six chronically prepared sheep, and cerebrospinal fluid (CSF) and arterial plasma clonidine were measured. Dural transfer of epidurally administered clonidine was rapid and extensive: time to maximal concentration (Tmax) in CSF was 32 +/- 8 min, bioavailability in CSF was 14 +/- 4% of the administered dose, and maximal CSF concentrations following epidural administration (820 +/- 30 ng/ml) were three orders of magnitude greater than those following iv injection (0.71 +/- 0.06 ng/ml). ⋯ Blood pressure increased and heart rate decreased following iv injection when plasma clonidine concentrations were high (greater than 2 ng/ml). Clonidine, following all routes of administration, numerically decreased blood pressure, but this decrease was significant only following epidural (mean arterial pressure = 97 +/- 6 mmHg before, 86 +/- 6 mmHg after; P less than 0.05) and intrathecal (93 +/- 9 mmHg before, 79 +/- 10 mmHg after; P less than 0.05) injection. Blood pressure decreased earlier following intrathecal than following epidural injection, corresponding with higher CSF clonidine concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Differences between handwritten and automatic blood pressure records.
Comparison of 46 handwritten and electromechanically generated blood pressure records revealed substantial differences between the recordings. The highest automated record pressures exceeded the highest pressures found in corresponding handwritten records. Similarly, the lowest pressures from automated records were lower than those from handwritten records. ⋯ No handwritten record contained a diastolic pressure above 110 mmHg. Discrepancies between handwritten and automatic records may arise from one or more causes. Among these are readings captured automatically but not observed by the anesthesiologist, faulty reconstruction of handwritten records from memory, and bias in favor of less controversial values.