Shared Decision-Making During Anesthesia Consent for Elective Cesarean Delivery (SDM-Consent)

Background. SDM, in which the clinician contributes evidence and the patient contributes values and preferences, is the ethical and increasingly the legal standard of consent (Hopp v Lepp; Reibl v Hughes; Montgomery v Lanarkshire). Major guidelines recommend neuraxial anesthesia for cesarean delivery because of the higher maternal risk of GA, and the SOAP Center of Excellence benchmark is a GA rate below 5%. Choice of technique is nevertheless preference-sensitive (being awake or asleep at the birth, partner presence, fear of needles or of awareness, prior trauma), and GA is routinely delivered when clinically required. Neuraxial block fails in about 5% of cesarean deliveries and intraoperative pain occurs in roughly 11-22%, a leading cause of maternal dissatisfaction and medicolegal action. The institutional consent discloses these risks. What varies between providers is choice: some present GA as a genuine primary option alongside neuraxial anesthesia, while others present neuraxial as the sole primary technique with GA only as rescue. A departmental poll found that 6 of 21 anesthesiologists (29%) report offering GA as a primary option. It is unknown whether offering GA as a genuine primary option affects women's perception of SDM.

Design. Single-centre, prospective, cross-sectional study at BC Women's Hospital, Vancouver. It combines (a) structured direct observation of the pre-operative anesthesia consent encounter and (b) a patient questionnaire on the 1st or 2nd postpartum day. No change is made to clinical care or to the consent process; existing variation in practice is the exposure. Because the anesthesiologist is assigned by the duty rota, women are quasi-randomly exposed to consent with or without a genuine primary choice.

Recruitment. A member of the circle of care (admitting nurse) asks the patient on the day of surgery whether they are willing to be approached. Only if they agree does a trained observer introduce the study and seek verbal assent to observation. Written informed consent is obtained 24-48 hours postpartum by a trained research assistant who is not the observer. The clinical anesthesia consent (routine care, observed) and the research consent (written, not observed) are separate processes. Providers receive an individual information sheet with an opt-out, and no per-case feedback is given. The specific exposure of interest is withheld from providers until study end; providers are not deceived about being observed.

Measures. Exposure: observer-classified offer of GA as a genuine primary option (yes/no). Observed SDM: OPTION-5, with at least 10% double-rated. Perceived SDM: SDM-Q-9 (primary outcome). Decisional conflict: Decisional Conflict Scale, descriptive. Future-choice preference. Covariates: age, parity, prior cesarean, prior anesthesia experience, education, gestational age, technique received, consultation duration.

Sample size and analysis. The primary analysis is a linear mixed-effects model with a random intercept for consenting provider, adjusted for covariates, reporting the adjusted mean difference with its 95% CI and the provider-level ICC. Assuming SD 12.4, alpha 0.05, a difference of 13.5 points, and ICC 0.10, 84 analyzable patients (4 per provider across 21 providers) give 97.7% power. Allowing about 20% attrition, the recruitment target is 105. A blinded biostatistician check of ICC, exposure split and SD after the first 105 patients will verify power; any increase in sample size will be submitted to the REB as an amendment. Reporting follows STROBE.

Data. Data are held in the institutional BCCHR/PHSA-hosted REDCap instance, keyed by study ID, with the re-identification key stored separately. Records are retained for 5 years after study completion and publication.