Early postoperative patient-controlled analgesia ratio predicts 24-hour morphine consumption and pain in children undergoing scoliosis surgery
Bibliographic record
Abstract
BACKGROUND: The identification of patients at risk for developing severe postoperative pain and/or opioid-related side effects is difficult due to a lack of sensitive indicators. The patient-controlled analgesia (PCA) ratio of demands to deliveries is a potential tool for early identification of patients who experience severe postoperative pain. The authors hypothesized that the PCA ratio is able to predict morphine requirement in the first 24 hours after scoliosis surgery. METHODS: The authors performed a retrospective study of adolescents who had surgery for idiopathic scoliosis. They collected data describing PCA demands and deliveries, morphine consumption, numerical rating scale (NRS) pain scores, opioid related side effects, and duration of hospital stay. Spearman rank analysis assessed association among 4-hour PCA ratios, NRS pain score, and 24-hour morphine consumption. Patients were divided into groups on the basis of PCA ratios <1.5 and ≥1.5. Univariate analysis and multiple regression were used to identify independent factors predictive for increased 24-hour morphine. Mann-Whitney rank-sum and Fisher exact tests were used to compare data. p < 0.05 was considered statistically significant. RESULTS: One hundred forty-seven patients were included in the analysis, mean (SD) age and weight were 15 (1.8) years and 55 (27) kg, respectively. There was a significant positive correlation between the 4-hour PCA ratio and initial 24-hour cumulative morphine consumption (r = 0.33, p = 0.0002). Patients with a 4-hour PCA ratio ≥1.5 demonstrated a significantly greater initial 24-hour morphine consumption (p = 0.0002), greater pain scores at 24 hours after surgery (p = 0.02), a greater incidence of at least one opioid-related side effect within the initial 24 hours after surgery, and a longer duration of hospital stay (p = 0.04) compared with those patients with a 4-hour PCA ratio <1.5. PCA ratio ≥1.5, age, and patient sex were predictive for 24-hour morphine consumption. CONCLUSIONS: The authors have demonstrated that a PCA ratio of demands/deliveries ≥1.5 is predictive of increased opioid requirements and is associated with greater pain scores in the initial 24 hours after surgery, an increased incidence of opioid-related side effects, and duration of hospital stay.
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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 | 0.003 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 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 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".