Hypnosedation in Relaxing Patients Undergoing Breast Cancer Surgery

Efficacy of HS

Will estimate the mean differences of these outcomes between groups and corresponding 90% confidence intervals at specified points in time (baseline, during the procedure, if applicable, and post-procedure), as well as across time points, using linear mixed models (LMMs). Will similarly evaluate the difference in the slope of change for these outcomes between arms. Baseline covariates such as those used in the minimization will be controlled for in our analyses. Time-varying predictors (such as electroencephalograms \[EEGs\]) may be controlled for in additional exploratory analyses. Standard model diagnostics will be applied to check for model assumptions, such as normality of the residual distribution.

Time frame: Up to 1 day

Assessment of changes in immune markers and endocrine function

Will estimate the mean differences of these outcomes between groups and corresponding 90% confidence intervals at specified points in time (baseline, during the procedure, if applicable, and post-procedure), as well as across time points, using linear mixed models (LMMs). Will similarly evaluate the difference in the slope of change for these outcomes between arms. Baseline covariates such as those used in the minimization will be controlled for in our analyses. Time-varying predictors (such as electroencephalograms \[EEGs\]) may be controlled for in additional exploratory analyses. Standard model diagnostics will be applied to check for model assumptions, such as normality of the residual distribution.

Time frame: Up to 14 days post-surgery

Changes in EEG activity as assessed using standardized low-resolution brain electromagnetic tomography (sLORETA)

One test for each of the nine frequency band pass regions will be conducted as well as voxel-by-voxel t-tests computed for the whole data set. For each subject, power means within the frequency bands will be summed across all electrode sites in both absolute and relative power. Within-group differences will be examined using paired-sample t-tests. Between-group differences will be examined using analysis of covariance (ANCOVA) with the condition as the fixed variable, baseline EEG scores as the covariate, and post intervention scores as the dependent variable. Percent signal changes will be computed at all six time points of interest in our predetermined regions of interest (ROIs).

Time frame: Baseline up to 14 days post-surgery

Group differences in medical costs

Will obtain detailed billing records from the date of surgery to the point of discharge at 14 days (+/- 5 days) and quantify medical costs in two ways. The first method is to apply cost-to-charge ratio to convert charges on the billing records to cost. The second method will identify from the study's institutional database each billing code appearing in patient's professional and technical charges, and calculate costs using Medicare reimbursement rates corresponding to current procedural terminology (CPT) codes. Because medical costs are highly skewed, the study will apply the non-parametric bootstrapping method to compare difference in medical costs between groups.

Time frame: From the date of surgery up to 14 days