Efficacy of Malignant Hyperthermia Association of the United States–Recommended Methods of Preparation for Malignant Hyperthermia-Susceptible Patients Using Dräger Zeus Anesthesia Workstations and Associated Costs
Bibliographic record
Abstract
BACKGROUND: The objective of this study was to assess the efficacy and cost of Malignant Hyperthermia Association of the United States-recommended methods for preparing Dräger Zeus anesthesia workstations (AWSs) for the malignant hyperthermia-susceptible patient. METHODS: We studied washout profiles of sevoflurane, isoflurane, and desflurane in 3 Zeus AWS following 3 preparation methods. AWS was primed with 1.2 minimum alveolar concentration anesthetic for 2 hours using 2 L/min fresh gas flow, 500 mL tidal volume, and 12/min respiratory rate. Two phases of washout were performed: high flow (10 L/min) until anesthetic concentration was <5 parts per million (ppm) for 20 minutes and then low flow (3 L/min) for 20 minutes to identify the rebound effect. Preparation methods are as follows: method 1 (M1), changing disposables (breathing circuit, soda lime, CO2 line, and water traps); method 2 (M2), M1 plus replacing the breathing system with an autoclaved one; and method 3 (M3), M1 plus mounting 2 activated charcoal filters on respiratory limbs. Primary outcomes are as follows: time to obtain anesthetic concentration <5 ppm in the high-flow phase, peak anesthetic concentrations in the low-flow phase, and for M3 only, peak anesthetic concentration after 70 minutes of low-flow phase, when activated charcoal filters are removed. Secondary outcomes are as follows: cost analysis of time and resources to obtain anesthetic concentration <5 ppm in each method and a vapor-free Zeus AWS. Sensitivity analyses were performed using alternative assumptions regarding the costs and the malignant hyperthermia-susceptible caseload per year. RESULTS: Primary outcomes were as follows: M3 instantaneously decreased anesthetic concentration to <1 ppm with minimal impact of low-flow phase. M1 (median, 88 minutes; 95% confidence interval [CI], 69-112 minutes) was greater than M2 (median, 11 minutes; 95% CI, 9-15 minutes). Means of peak rebound anesthetic concentrations in M1, M2, and M3 were 15, 6, and 1 ppm, respectively (P < .001). Anesthetic concentration increased 33-fold (95% CI, 21-50) after removing charcoal filters (from 0.7 to 20 ppm). The choice of anesthetic agents did not impact the results. Secondary outcomes were as follows: M3 was the lowest cost when the cost of lost operating room (OR) time due to washout was included, and M1 was the lowest cost when it was not included. When the cost of lost OR time due to washout was considered the estimated cost/case of M3 was US $360 (M1, US $2670; M2, US $969; and a "vapor-free" Zeus AWS was US $930). The OR time and equipment costs represent the largest differentiators among the methods. CONCLUSIONS: Institutions in which demand for OR time has exceeded capacity should consider M3, and institutions with surplus OR capacity should consider M1.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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 teacher head, 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".