Desflurane provides faster wash-in and wash-out than sevoflurane in morbidly obese patients, and recovery is much faster after desflurane administration when no premedication has been used.

Weight adjustment causes a clinically unacceptable performance bias, which is not corrected when TBW is used as an input to the 'Marsh' model. It is, therefore, advisable to administer propofol to morbidly obese patients by titration to targeted processed-EEG values.

The median values (interquartile ranges) of the MDPE, MDAPE, divergence and wobble for the James equations during maintenance were -53.4% (-58.7% to -49.2%), 53.4% (49.0-58.7%), 3.3% (2.9-4.7%) and 1.4% h(-1) (1.1-2.5% h(-1)), respectively. The respective values for the Janmahasatian equations were -18.9% (-24.2% to -10.4%), 20.5% (13.3-24.8%), 2.6% (-0.7% to 4.5%) and 1.9% h(-1) (1.4-3.0% h(-1)). The performance (in terms of the MDPE and MDAPE) of the corrected pharmacokinetic set was better than that of the uncorrected one. The predictive performance of the original pharmacokinetic set is not clinically acceptable. Use of a corrected LBM value in morbidly obese patients corrects this pharmacokinetic set and allows its use in obese patients. The 'fictitious height' can be a valid alternative for use of TCI infusion of remifentanil in morbidly obese patients until commercially available infusion pumps and research software are updated and new LBM equations are implemented in their algorithms.

Significant bias between predicted and measured plasma propofol concentrations was found while the low wobble values suggest that propofol TCI system is able to maintain stable drug concentrations over time. As already suggested before, a computer simulation confirmed that the TCI system performance could be significantly improved when total body weight is used.

Morbid obesity is defined as body mass index (BMI) > 35 kg.m(-2), and super-obesity as BMI > 55 kg.m(-2). We report the case of a 290-kg super-obese patient scheduled for open bariatric surgery. A propofol-remifentanil TCI (target controlled infusion) was chosen as the anaesthetic technique both for sedation during awake fibreoptic nasotracheal intubation and for maintenance of anaesthesia during surgery. Servin's weight correction formula was used for propofol. Arterial blood samples were taken at fixed time points to assess the predictive performance of the TCI system. A significant difference between measured and predicted plasma propofol concentrations was found. After performing a computer simulation, we found that predictive performance would have improved significantly if we had used an unadjusted pharmacokinetic set. However, in conclusion (despite the differences between measured and predicted plasma propofol concentrations), the use of a propofol-remifentanil TCI technique both for sedation during awake fibreoptic intubation and for Bispectral Index-guided propofol-remifentanil anaesthesia resulted in a rapid and effective induction, and operative stability and a rapid emergence, allowing rapid extubation in the operating room and an uneventful recovery.