Effect of Intravenous Phenobarbital on Left Ventricular Myocardial Contractility Determined by Echocardiography in Children
Bibliographic record
Abstract
INTRODUCTION: Animal studies and rare human studies have suggested a negative effect of barbiturates on cardiac function. Although intravenous (IV) phenobarbital is used routinely in children in the clinical setting, studies in children are lacking. We performed a study to evaluate effect of IV phenobarbital loading on myocardial systolic function of children. METHODS: In a prospective pilot study in children without congenital heart defects, the effect of IV phenobarbital was evaluated on the left ventricular systolic function measured by ejection fraction (EF) by Simpson's method via an echocardiogram. Any child less than 18 years of age who received IV loading dose of at least 20 mg/kg of phenobarbital given as an infusion over 20 - 30 minutes for various medical indications was eligible to take part in the study. Three measurements of EF by an echocardiogram were made: before loading dose, 30 minutes after completion of the loading dose, and prior to the first maintenance dose. Relevant clinical data were recorded, including vital signs, immediately prior to each echocardiogram. Change of function as measured by EF over time was analyzed using linear mixed modeling methods. For this study, significant change in blood pressure was defined as a drop of at least 20 mmHg in systolic blood pressure. RESULTS: Ten children (70% female, age range two days to 8.2 years) were enrolled. Three had hypotension with a drop of systolic blood pressure greater than 20 mmHg from baseline. On examining the trajectory of EF on each individual graphically, the left ventricular EF tended to fall immediately following phenobarbital therapy and return to baseline on re-evaluation. These trajectories were statistically significant for EF. CONCLUSIONS: Phenobarbital had a direct and transient depressant effect on systolic function of the myocardium in one third of the cases. The depression in EF appeared to be transient with return to baseline in less than 24 hours. We recommend close monitoring with anticipation of decreased function in children when using IV phenobarbital.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".