A functional regression analysis of vessel source level measurements from the Enhancing Cetacean Habitat and Observation (ECHO) database.

Measurements of the source levels of 9880 passes of 3188 different large commercial ships from the Enhancing Cetacean Habitat and Observation (ECHO) program database were used to investigate the dependencies of vessel underwater noise emissions on several vessel design parameters and operating conditions. Trends in the dataset were analyzed using functional regression analysis, which is an extension of standard regression analysis and represents a response variable (decidecade band source level) as a continuous function of a predictor variable (frequency). The statistical model was applied to source level data for six vessel categories: cruise ships, container ships, bulk carriers, tankers, tugs, and vehicle carriers. Depending on the frequency band and category, the functional regression model explained approximately 25%-50% of the variance in the ECHO dataset. The two main operational parameters, speed through water and actual draft, were the predictors most strongly correlated with source levels in all of the vessel categories. Vessel size (represented via length overall) was the design parameter with the strongest correlation to underwater radiated noise for three categories of vessels (bulkers, containers, and tankers). Other design parameters that were investigated (engine revolutions per minute, engine power, design speed, and vessel age) had weaker but nonetheless significant correlations with source levels.

Predictors of cesarean section following elective post-dates induction of labor in nullipara with uncomplicated singleton vertex pregnancies.

OBJECTIVE: Although post-dates is among the most common indications for induction of labor, no studies have identified the predictors of cesarean section (C/S) in that population. The high cesarean rate in our institution for this group of women triggered us to assess different induction practices to elicit potential causes. METHODS: We conducted a hospital-based retrospective cohort analysis using chart reviews of all nullipara women with induced labor at the Children's and Women's Health Centre of British Columbia, Vancouver, Canada, during the 2-year period, April 1998 to March 2000. The C/S rate was compared among 3 groups of women who were divided according to their induction method. RESULTS: Three hundred and thirty-nine women meeting the inclusion criteria were induced. Of the 25 women who received oxytocin ideally and the 111 women who did not, 7 (28%) and 53 (48%) were delivered by C/S, (x2=3.228 p=0.07; relative risks 0.59 [95% confidence interval 0.30, 1.13]). A significantly lower C/S rate (x2=21.9, p<0.0005) was found among women induced with prostaglandin (PG) alone (19.4%) compared with those induced with PG and oxytocin, whether oxytocin was given ideally (38.3%) or not ideally (45.4%). Of women who received oxytocin, there was no difference in chorioamnionitis (x2=0.485, p=0.49) between those who had an early membrane rupture (with or pre-oxytocin, 22.4%) and those who had membrane rupture following a period of oxytocin infusion (18.5%). CONCLUSION: The need for oxytocin or less than 2 doses of PG is associated with increased risk of C/S. Whether oxytocin was given according to protocol (ideally) or not, made no difference to the C/S risk in this population.

The prediction of adverse maternal outcomes in preeclampsia.

OBJECTIVES: (1) To evaluate whether clinical variables reflecting the multiorgan dysfunctions of preeclampsia can predict adverse maternal outcomes of preeclampsia; (2) to determine the usefulness of the mean platelet volume (MPV):platelet ratio as a novel measure of platelet consumption in predicting the severity of preeclampsia. METHOD: A retrospective chart review was conducted of cases of preeclampsia seen in 3 tertiary level units from January 2001 to December 2001. Candidate predictors of adverse maternal outcome were gestational age (GA) on admission to hospital, blood pressure, proteinuria, urine output, uric acid, creatinine, aspartate transaminase (AST), lactate dehydrogenase, bilirubin, albumin, fraction of inspired oxygen:oxygen saturation (FIO2:SaO2) ratio, platelet count, MPV, MPV:platelet ratio, fibrinogen, and seizures. The combined adverse maternal outcomes included maternal death; 1 or more of hepatic failure, hematoma, or rupture; Glasgow coma scale <13; stroke; 2 or more seizures; cortical blindness; positive inotrope support; myocardial infarction; infusion of any third antihypertensive; dialysis; renal transplantation; > or =50% FIO2 for >1 hour; intubation; or transfusion of > or =10 units of blood products. Descriptive, univariable, and multivariable analyses were performed, with significance set at P < .05. RESULTS: Of a total of 594 women with preeclampsia, 60 (10.1%) developed at least 1 element of the combined adverse outcome; 1 of these 60 women died. The most common outcomes were increased oxygen requirements, the use of a third infused antihypertensive, and transfusion >10 units. In women who developed an adverse outcome, GA and fibrinogen were lower, and total leukocyte count, creatinine, and AST were greater. Multivariable logistic regression revealed that admission GA (odds ratio [OR], 0.91), dipstick protein (OR, 1.31), and MPV:platelet ratio (OR, 391.0) independently predicted the outcome. CONCLUSIONS: Several promising markers were identified: admission GA, dipstick proteinuria, and the MPV:platelet ratio. MPV:platelet ratio also showed promise as a marker of platelet consumption. A prospective study is required to develop a clinical prediction model for preeclampsia.