A survey of non-depolarising muscle relaxants used in cardiac anaesthesia and surgery

Introduction: Residual neuromuscular blockade contributes to postoperative morbidity and mortality, and is more common with long-acting non-depolarising muscle relaxants (NDMRs) such as pancuronium [1]. This phenomenon may be a common occurrence in 'fast-track' managed cardiac patients administered long-acting NDMRs. We examine the usage of NDMRs in cardiac anaesthesia in the United Kingdom. Methods: A postal questionnaire was sent to 310 consultant cardiac anaesthetists in the United Kingdom. We asked which NDMRs are preferred (differentiating between 'fast-track' [FT] and 'non-fast-track' [NFT] management of patients), and what methods are used to assess neuromuscular function prior to extubation. Results: There was a 72.6% (225/310) response rate, of which 217 responses were valid. A single-agent NDMR technique is most prevalent for both NFT (92.2%) and FT patients (88.5%). Pancuronium (either as sole agent or in combination with another NDMR) was the first choice for NFT and FT patients, 73.7% and 52.1% respectively. For both management strategies, rocuronium is the next most popular agent. Benzylisoquinolinium derivatives are not in common usage. Forty-nine out of 211 anaesthetists (where a comparison could be made) changed their choice of NDMR between NFT and FT patients. The majority of these anaesthetists (85.7%) remove pancuronium from their practice for FT patients. Of respondents, 20.7% (45/217) indicated that an assessment of neuromuscular function was part of an extubation protocol; 75.6% (34/45) of these respondents detailed only clinical methods, whilst 6.7% (3/45) indicated use of a 'neuromuscular function monitor' alone, with 15.6% (7/45) indicating use of both methods. Amongst the responses indicating 'neuromuscular function monitor' methods, an assessment of the 'train-of-four' was the commonest response. Less than 10% monitor the neuromuscular junction during surgery. Conclusions: Pancuronium remains the most popular NDMR for all types of cardiac anaesthesia. Some anaesthetists modify their choice of NDMR for FT management, changing from pancuronium to a shorter acting NDMR as the commonest adaptation. A minority of respondents indicated that a protocol exists to routinely assess the neuromuscular function prior to extubation. Introduction: Many patients develop, to a varying extent, a metabolic acidosis during cardiopulmonary bypass (CPB). Often this acidosis is assumed to be the result of tissue hypoperfusion. However, fluids administered to patients before and during CPB, through their effects upon the strong ion difference (SID), may cause metabolic acidosis [1,2]. These fluids may also produce acidosis by haemodilution because of the decrease in plasma protein concentration [2]. The aim of this study was to determine …