Anesthesiology
-
Randomized Controlled Trial Clinical Trial
Recruitment maneuvers after a positive end-expiratory pressure trial do not induce sustained effects in early adult respiratory distress syndrome.
Recruitment maneuvers performed in early adult respiratory distress syndrome remain a matter of dispute in patients ventilated with low tidal volumes and high levels of positive end-expiratory pressure (PEEP). In this prospective, randomized controlled study the authors evaluated the impact of recruitment maneuvers after a PEEP trial on oxygenation and venous admixture (Qs/Qt) in patients with early extrapulmonary adult respiratory distress syndrome. ⋯ In patients with early extrapulmonary adult respiratory distress syndrome who underwent a PEEP trial, recruitment maneuvers failed to induce a sustained improvement of oxygenation and venous admixture.
-
Previous work has demonstrated that ongoing hemorrhagic shock dramatically alters the distribution, clearance, and potency of propofol. Whether volume resuscitation after hemorrhagic shock restores drug behavior to baseline pharmacokinetics and pharmacodynamics remains unclear. This is particularly relevant because patients suffering from hemorrhagic shock are typically resuscitated before surgery. To investigate this, the authors studied the influence of an isobaric bleed followed by crystalloid resuscitation on the pharmacokinetics and pharmacodynamics of propofol in a swine model. The hypothesis was that hemorrhagic shock followed by resuscitation would not significantly alter the pharmacokinetics but would influence the pharmacodynamics of propofol. ⋯ Hemorrhagic shock followed by resuscitation with lactated Ringer's solution did not alter the pharmacokinetics but did increase the potency of propofol. These results demonstrate that alterations in propofol pharmacokinetics observed in moderate to severe blood loss can be reversed with resuscitation. These results suggest that a modest reduction in propofol is prudent to achieve a desired drug effect after resuscitation from severe hemorrhagic shock.
-
Comparative Study Clinical Trial
Comparative pharmacokinetics and pharmacodynamics of the new propofol prodrug GPI 15715 and propofol emulsion.
GPI 15715 is a new water-soluble prodrug that is hydrolyzed to release propofol. The objectives of this crossover study in volunteers were to investigate the pharmacokinetics and pharmacodynamics of GPI 15715 in comparison with propofol emulsion. ⋯ Compared with propofol emulsion, propofol from GPI 15715 showed different pharmacokinetics and pharmacodynamics, particularly a higher potency with respect to concentration. These differences may indicate an influence of the formulation.
-
The currently available pharmacokinetic models for fentanyl were derived from normal weight patients and were not scaled to body weight. Their application to obese patients may cause overprediction of the plasma concentration of fentanyl. This study examined the influence of body weight on the predictive accuracy of two models (Anesthesiology 1990; 73:1091-102 and J Pharmacol Exp Ther 1987; 240:159-66). Further, we attempted to derive suggested dosing mass weights for fentanyl that improved predicted accuracy. ⋯ Actual body weight overestimates fentanyl dose requirements in obese patients. Dosing weight (pharmacokinetic mass) derived from the nonlinear relationship between prediction error and TBW proved to have a linear relationship with clearance.
-
A lung-protecting strategy is essential when ventilating acute lung injury/acute respiratory distress syndrome patients. Current emphasis is on limiting inspiratory pressure and volume. This study was designed to investigate the effect of peak inspiratory flow on lung injury. ⋯ When an injurious tidal volume is delivered, the deterioration in gas exchange and respiratory mechanics, and lung injury appear to be marked at a high peak inspiratory flow.