Clinical course of gamma-hydroxybutyrate overdose.

STUDY OBJECTIVE: To describe the clinical characteristics and course of gamma-hydroxybutyrate (GHB) overdose. METHODS: We assembled a retrospective series of all cases of GHB ingestion see in an urban public-hospital emergency department and entered in a computerized database January 1993 through December 1996. From these cases we extracted demographic information, concurrent drug use, vital signs, Glasgow Coma Scale (GCS) score, laboratory values, and clinical course. RESULTS: Sixty-one (69%) of the 88 patients were male. The mean age was 28 years. Thirty-four cases (39%) involved coingestion of ethanol, and 25 (28%) involved coingestion of another drug, most commonly amphetamines. Twenty-five cases (28%) had a GCS score of 3, and 28 (33%) had scores ranging from 4 through 8. The mean time to regained consciousness from initial presentation among nonintubated patients with an initial GCS of 13 or less was 146 minutes (range, 16-389). Twenty-two patients (31%) had an initial temperature of 35 degrees C or less. Thirty-two (36%) had asymptomatic bradycardia; in 29 of these cases, the initial GCS score was 8 or less. Ten patients (11%) presented with hypotension (systolic blood pressure < or = 90 mm Hg); 6 of these patients also demonstrated concurrent bradycardia. Arterial blood gases were measured in 30 patients; 21 had a PCO2 of 45 or greater, with pH ranging from 7.24 to 7.34, consistent with mild acute respiratory acidosis. Twenty-six patients (30%) had an episode of emesis; in 22 of these cases, the initial GCS was 8 or less. CONCLUSION: In our study population, patients who overdosed on GHB presented with a markedly decreased level of consciousness. Coingestion of ethanol or other drugs is common, as are bradycardia, hypothermia, respiratory acidosis, and emesis. Hypotension occurs occasionally. Patients typically regain consciousness spontaneously within 5 hours of the ingestion.

Physiological control of sibilant duration: insights afforded by speech compensation to dental prostheses.

Temporal relationships among tongue contact, phonation, and presence of frication were examined for /s/ and /z/. In cases where /s/ and /z/ were produced with a supraglottal articulation of the same duration, the duration of the resulting frication was 17 ms longer for /s/. The difference can be attributed to glottal activity. The presence of a unfamiliar dental prosthesis in the mouth caused the tongue to contact the alveolar ridge sooner and release later. This physiological effect was reflected in lengthening of frication for sibilants, but the acoustical consequences were greater and more reliable for /z/ than for /s/. Reasons for this difference were sought in adaptation of timing of tongue contact, and in aerodynamic conditions expected for voiced versus voiceless sibilants. A rapid adaptation of tongue contact timing was found, with the adaptation being greater for /s/. Timing of vocal fold adduction at the end of unvoiced sibilants, and its aerodynamic consequences, are suggested to consequences, are suggested to contribute to the relative stability of /s/ acoustical durations.