Neostigmine antagonism of rocuronium block during anesthesia with sevoflurane, isoflurane or propofol

Purpose: To examine the influence of continuing administration of sevoflurane or isoflurane during reversal of rocuronium induced neuromuscular block with neostigmine. Methods: One hundred and twenty patients, divided into three equal groups, were randomly allocated to maintenance of anesthesia with sevoflurane, isoflurane or propofol. Neuromuscular block was induced with rocuronium and monitored using train-of-four (TOF) stimulation of the ulnar nerve and recording the force of contraction of the adductor pollicis muscle. Neostigmine was administered when the first response in TOF had recovered to 25%. At this time the volatile agent administration was stopped or propofol dosage reduced in half the patients in each group (n = 20 in each group). The times to attain TOF ratio of 0.8, and the number of patients attaining this end point within 15 min were recorded. Results: The times (mean ± SD) to recovery of the TOF ratio to 0.8 were 12.0 ± 5.5 and 6.8 ± 2.3 min in the sevoflurane continued and sevoflurane stopped groups, 9.0 ± 8.3 and 5.5 ± 3.0 min in the isoflurane continued and isoflurane stopped groups, and 5.2 ± 2.8 and 4.7 ±1.5 min in the propofol continued and propofol stopped groups (P <0.5- 01). Only 9 and 15 patients in the sevoflurane and isoflurane continued groups respectively had attained a TOF ratio of 0.8 within 15 min (P <0.001 for sevoflurane). Conclusions: The continued administration of sevoflurane, and to a smaller extent isoflurane, results in delay in attaining adequate antagonism of rocuronium induced neuromuscular block.

Anti-sized reed bed system for animal wastewater treatment: a comparative study

This paper presents a comparative study on the treatment of high-strength animal wastewater in two parallel lab-scale constructed reed bed systems, progressively-sized system and anti-sized system, which have same configuration but different arrangement of bed media. The reed bed systems were operated in a tidal flow pattern to treat diluted pig slurry. Detailed analyses were carried out for the removal of some key pollutants including COD, BOD5, NH4-N, P and suspended solids. The results showed that both systems have considerable capacity for the removal of solids, organic matter and inorganic nutrients. The formation of biofilms on the surfaces of gravel media in both reed bed systems was monitored by scanning selected gravel samples using scanning electron microscopy. In general, no significant difference was detected with regard to the percentage pollutant removal in the systems. However, the anti-sized system demonstrated a clear advantage in its ability to slow down the clogging of bed media and avoid the impairment of long-term functioning and sustainability of the beds. A conceptual model was developed to predict the occurrence of the clogging. The validity of the model was tested using data from this study and from the literatures.

Assessment of fighting ability in animal contests

Selection should favour accurate information gathering regarding the likely costs and benefits of continued conflict. Here we consider how variation in the abilities of contestants to assess resource-holding potential (RHP) influences fights. This has been examined in various game theory models. However, discriminating between assessment strategies has proven difficult and has resulted in confusion. To add clarity, we group existing models into three main types that differ in the information about RHP that contestants are presumed to gather: (1) pure self-assessment, (2) cumulative assessment and (3) mutual assessment. Within this framework we outline methods advocated to discriminate successfully between the three main assessment models. We discuss support for each model, before highlighting a number of conflicting and inconclusive studies, leading us to consider alternative approaches to investigate assessment. Furthermore, we examine support for newly emerging concepts such as 'varying degrees of assessment', 'switching assessment' strategies and the possibility of contestants adopting different assessment strategies within a fight involving distinctive roles. We suggest future studies will benefit by judicious use of a battery of techniques to determine how animals settle contests. Finally, we highlight difficulties with current game theory models, and raise concerns regarding the use of certain behavioural criteria to accept or reject a model, particularly since this may conflict with evidence for a given assessment strategy. Furthermore, the failure of existing models to account for newly emerging concepts points to limitations of their use and leads us to challenge game theoreticians to develop upon them. (C) 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.