No abstract

Background: Limited data are available about the difference in propofol plasma levels estimated by target controlled infusion models (TCI) and measured plasma levels during prolonged operations. We hypothesized the difference to be greater at the end of surgery than at the beginning.Methods: For this prospective observational study, adult patients were enrolled (elective surgery, estimated operating time of ≥ 3 hours, eligible to receive propofol using TCI (Schnider model)). Blood was sampled in steady state after anesthesia induction (propofol dosed to achieve BIS values of 40-60; T 1 ) and at the end of the procedure (T 2 ). Fluid balance was recorded. Bias and limits of agreement of actual plasma levels (C blood ) to TCI values (C TCI ) were calculated, hemodynamics assessed, and performance error (PE) measured (PE(%) = ((C blood -C TCI )/C TCI )*100) and assessed for correlations.Results: Thirty patients were included. Mean duration of procedure was 250 min (± 136.7), fluid balance 2066 ml (± 1017), and all patients were hemodynamically stable. Mean C TCI was 2.0 µ/ml (± 0.3) and 1.8 µ/ml

In December 2001, the Maryland State Highway Administration (SKA) opened a single bid for the substructure and superstructure contract to replace the Woodrow Wilson Memorial Bridge, the crossing of the Potomac River for I-95 and I-495 (Capital Beltway) traffic. This contract was part of the larger Woodrow Wilson Bridge project, a $2.5 billion project to build the new Potomac River crossing and to reconstruct the four interchanges in its vicinity. The contract’s estimate was a record for SHA at $487 million. The single bid was for a budget-wrecking $860 million and was rejected. The design team regrouped and focused its efforts on innovative means for bringing the project back on budget. Maryland SHA convened an independent review committee (IRC). Composed of industry experts, the IRC advised the design team on making the contract less expensive and more attractive to contractors to increase competition and reduce costs. Ultimately, the work was readvertised as three separate contracts. The outcome of redesigning and readvertising was to reduce the total bid amount for the work by $362 million. Several lessons were learned in handling megaprojects: reach out to the construction industry early and often to rouse and maintain interest in the project; make terms of the contracts as contractor friendly as reasonable; and, when sizing the contract, ensure that it is manageable and that it balances competition and contract interface risk.