ABSTRACTS
Additional prospective studies should be undertaken to verify and reproduce the above findings. Surely outcome and morbidity studies are the true way to evaluate such technology and its clinical indications.] Lynn Keating, MD vecuronium, neuromuscular blocking agents
Onset and duration of n e u r o m u s c u l a r b l o c k a d e following high.dose vecuronium administration Ginsberg B, Glass PS, Quill T, et al Anesthesiology 71:201-205 Aug 1989
A rapid and predictable onset of neuromuscular blockade is needed for rapid sequence endotracheal intubation. A study using high-dose vecuronium as an alternative to succinylcholine was performed. To determine the time to blockade, duration of blockade, hemodynamics, and endotracheal intubating conditions following high doses of vecuronium, 40 ASA physical status I and II patients scheduled for elective surgery were selected. These patients were randomly assigned to doses of either 100, 200, 300, or 400 ~g/kg vecuronium. Neuromuscular blockade was quantitated continuously using surface electrodes and EMG recordings. When electromyogram calibrations fell to less than 20% of control, intubating conditions were assessed using a four-point scale. Systolic, diastolic, and mean arterial pressure, and heart rate were recorded every two minutes from induction of anesthesia until ten minutes after intubation. Time to complete abolition of twitch tension (onset time) and to 25% recovery of twitch tension (duration time) also was recorded. Time to intubation varied from 183 ± 24 seconds in the 100 ~g/kg group to 96 -+- 31 seconds in the 400 ixg/kg group. Increasing the dose of vecuronium from 100 to 400 ~g/kg decreased the onset time from 208 _+ 41 seconds to 106 _+ 35 seconds. A linear increase in duration of blockade was found as the dose of vecuronium was increased. Intubating conditions were rated as good or excellent in all groups, with no statistical difference in h e m o d y n a m i c s found between groups. The authors conclude that use of high-dose vecuronium may be a viable alternative to succinylcholinc when rapid onset of neuromuscular blockade is needed.
Roger A Smith, MD thyroxine, overdose, pediatric
A c u t e thyroxine ingestion in pediatric patients Lewander WJ, Lacouture PG, Silva JE, et al Pediatrics 48:262-265 Aug 1989
This prospective study investigated 15 pediatric cases of 168/216
thyroxine (T4) overdose during a one-year period. Inclusion criteria were a history of an acute T4 ingestion in a patient not undergoing thyroid hormone replacement therapy, age of 5 years or less, and determination of an initial serum T4 concentration. Estimated dosage ranged from 1.5 to 8.8 mg (0.1 to 0.73 mg/kg). All patients were examined between one and six hours after ingestion and were initially asymptomatic. However, three patients with T4 concentrations of more than 75 }~g/kg manifested signs of toxicity such as fever, tachycardia, hypertension, and agitation within 12 to 48 hours; these resolved in 24 to 60 hours. The other 12 patients (80%) remained asymptomatic. Treatment of all patients consisted of gastrointestinal decontamination with ipecac and/or activated charcoal with cathartic. Four patients received propylthiouracil to decrease T4 to T3 conversion, three received acetaminophen for fever, and two received propanolol for adrenergic overactivity. Eight patients were hospitalized for an average of 78 hours; there were no deaths. The mean elimination half-lives of T4 and T3 in acute ingestion were found to be 2.8 and 6.0 days, respectively, compared with three to five days and one day, respectively, under physiologic conditions. The ongoing conversion of T4 to T3 may explain the long elimination half-life of T3 in this study. The authors conclude that the majority of pediatric T4 ingestions are not severe and may be managed on an outpatient basis. In patients ingesting large (more than 4 mg) or unknown quantities of T4, an initial T4 concentration may predict delayed onset of toxicity in the absence of early clinical manifestations. Admission should be considered for all symptomatic patients or those with T4 levels of more than 75 txg/dL regardless of presentation.
Carol Federiuk, MD carbon monoxide, toxicity
M e a s u r e m e n t of expired carbon monoxide to evaluate carboxyhemoglobin saturation in patients with possible carbon monoxide poisoning Mols P, Bruyninx J, Naeije M, et al JEUR 1:29-32 1988
A prospective study was done to determine the ease of use and reliability of a commercially available hand-held, noninvasive method to measure expired gas carboxyhemoglobin saturation. Previous studies had already shown that a linear correlation exists between expired carboxyhemoglobin (COHb) and blood carboxyhemoglobin levels. In this study expired carbon monoxide measurements were compared w i t h s p e c t r o p h o t o m e t r i c m e a s u r e m e n t s of COHb in the blood. Forty-five patients admitted to a European university hospital for carbon monoxide poisoning participated in the study. Twenty-four (53%) patients had a COHb of more than 15% and 37.8% had levels of more
Annals of EmergencyMedicine
19:2 February 1990