The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

The influence of dissolved and particulate materials on underwater light fields in shelf seas: implications for primary production modelling

The effects that particulate and coloured dissolved materials had on the underwater light field were examined using a combination of in situ observations and radiance transfer modelling. Hydrolight (a commercially available radiance transfer software program) was used to validate in-situ measurements of inherent optical properties (IOP's). A general set of specific optical cross sections were derived which allowed the nature of the underwater light field to be determined from the concentrations of chlorophyll (Chl), coloured dissolved organic matter (CDOM) and suspended minerals (MSS) The attenuation coefficient of irradiance at 490 nm (K-d490) was linearly correlated with the depth at which the surface irradiance reached 1% of its original value. A study was carried out to determine whether there were any advantages in taking hyperspectral measurements of the underwater light field as opposed to seven waveband multi-spectral measurements. It was found that there was no significant difference between hyperspectral and 7 waveband measurements at the surface, but there was a 20% difference at a depth equivalent to 5 optical depths. Finally, the light harvesting strategies of two different phytoplankton functional groups (diatoms and chlorophytes) were examined in waters with high concentrations of dissolved and particulate materials to assess whether the accessory light harvesting pigments in diatoms gave that group an advantage