The Effects of an Increase of Central Blood Volume Before Spinal Anesthesia for Cesarean Delivery: A Qualitative Systematic Review
Bibliographic record
Abstract
UNLABELLED: We evaluated in this qualitative systematic review the efficacy of increasing central blood volume on the incidence of hypotension after spinal anesthesia for elective cesarean delivery. Randomized controlled trials investigating any method of increasing central blood volume before the initiation of obstetric spinal anesthesia were sought by using MEDLINE (1966-2000), Embase (January 1988-April 2000), and the Cochrane Library (Issue 1, 2000). Additional reports from retrieved and review articles, hand searching of non-MEDLINE journals, and abstracts of major anesthesia meetings (1994-1999) were located. The primary outcome was the incidence of hypotension. Secondary outcomes included: ephedrine use, Apgar scores, umbilical cord pH values, and maternal nausea and vomiting. Twenty-three articles met our inclusion criteria with the use of crystalloid preload, colloid preload, and mechanical methods of increasing central volume. Crystalloid preload was inconsistent in preventing hypotension, whereas colloid appeared to be effective in all but one study. Leg wrapping and thromboembolic stockings decreased the incidence of hypotension compared with leg elevation or control. Few differences in fetal outcomes or maternal nausea and vomiting were reported. Increasing central blood volume by using colloid and leg wrapping decreases but does not abolish the incidence of hypotension before spinal anesthesia for elective cesarean delivery. IMPLICATIONS: We performed a systematic review to determine whether fluid loading reduced the incidence of low blood pressure after spinal anesthesia for cesarean delivery. Although no technique totally eliminates the occurrence of hypotension, colloid administration (starch or gelatin containing fluids) and leg wrapping were the most effective.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.051 | 0.153 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.003 |
| Bibliometrics | 0.012 | 0.012 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".