Biomedical subjects
Publications and source records attributed to C L Gwinnutt.
Complications arising from operations on the cervical spine through an anterior approach are relatively uncommon. However, the surgical territory is such that when complications do arise they can be serious and occasionally life-threatening. We report the case of a patient who developed acute respiratory obstruction after Cloward's procedure.
Antagonism of intense neuromuscular block induced by atracurium 0.5 mg kg-1 was attempted in four groups of six children using one of two doses of neostigmine (0.05 mg kg-1 and 0.1 mg kg-1) or of edrophonium (0.5 mg kg-1 and 1.0 mg kg-1) when the first twitch of the post-tetanic count (PTC1) was 10% of control. For comparison with normal practice, a fifth group received neostigmine 0.05 mg kg-1 when the first twitch of the train-of-four was 10% of control. Total recovery time from PTC1 10% to a train-of-four ratio of 0.8 was not reduced by early administration of the anticholinesterases, compared with conventional administration of neostigmine at T1 10%. However, recovery from intense block was faster after neostigmine than edrophonium (P less than 0.01). Doubling the doses of the anticholinesterases did not reduce the recovery time and had the effect of increasing variability. We conclude that there is no clinical advantage in attempting to antagonize intense neuromuscular block in children using normal or increased doses of neostigmine or edrophonium.
A wide variety of surgical and pharmacological methods have been described in an attempt to reduce pain after tonsillectomy, with conflicting results. Opiates are still widely used, despite unwanted side-effects. Recently the non-steroidal anti-inflammatory drugs have been shown to be effective against a variety of post-operative pains. Diclofenac is effective in both children and adults in the relief of pain after tonsillectomy when administered rectally, but absorption is variable, and suppositories are not widely accepted in the UK. The present double-blind study compared a single intramuscular dose of diclofenac with papaveretum in adults undergoing tonsillectomy. Post-operatively, the patients who received diclofenac had less pain and started drinking significantly sooner than the control group. There were no undesirable side-effects. Intramuscular diclofenac is superior to papaveretum in the relief of pain in adults undergoing tonsillectomy.
Nitrous oxide is now recognised as an important contributor to the 'greenhouse' effect. Each year the medical profession unwittingly adds a very small burden of this gas to the atmosphere. Unfortunately, the long lifetime of nitrous oxide means that all emissions into the atmosphere are significant. By making small changes in their practices, anaesthetists are well-placed to help reduce the potential environmental damage.
We have measured concentrations of atracurium and laudanosine in cerebrospinal fluid (CSF) and plasma in three intensive care patients receiving atracurium infusions of 22.5-106 h duration to maintain neuromuscular block. Two patients had suffered severe closed head injuries and the third patient had developed respiratory failure following the clipping of two intracranial aneurysms. The total dose of atracurium given was 14.3-136.6 mg kg-1; rate of infusion was 0.6-1.38 mg kg-1 h-1. Plasma concentrations of atracurium and laudanosine were 0.73-3.11 micrograms ml-1 and 0.48-8.65 micrograms ml-1, respectively; CSF concentration of laudanosine was 70-440 ng ml-1. No adverse effects attributable to these concentrations of laudanosine were observed.
Concentrations of atracurium and laudanosine in cerebrospinal fluid (CSF) and plasma were assayed in nine patients receiving atracurium infusions of 111-251 min duration to maintain neuromuscular block during intracranial surgery. The total dose of atracurium was 1.57-2.60 mg kg-1 and the plasma concentration of atracurium was 1.27-5.44 micrograms ml-1. Concentrations of laudanosine in CSF and plasma increased during the infusion period, and after 125-140 min reached means of 202.5 ng ml-1 and 1448.7 ng ml-1, respectively. The highest recorded concentration of laudanosine in CSF was 570 ng ml-1, in one of two CSF samples found to contain atracurium. After operation, two patients had fits, but these were not thought to be related to laudanosine. It is concluded that during infusion of atracurium, laudanosine accumulates in both plasma and CSF.
The post-tetanic count was investigated as a method of monitoring intense neuromuscular blockade in children. One of five myoneural blockers (atracurium, vecuronium, pancuronium, tubocurarine or alcuronium) was given to groups of six children during nitrous oxide-oxygen-halothane anaesthesia. During recovery, the first post-tetanic response always preceded the first train-of-four response. The interval between the appearance of the first post-tetanic response and the first train-of-four response was typically 5-10 min for the intermediate-acting agents vecuronium and atracurium, and 20-30 min for the long-acting agents pancuronium, alcuronium and tubocurarine. A post-tetanic count of 6 with alcuronium and tubocurarine, or 7 with vecuronium, atracurium and pancuronium indicated that recovery of the first train-of-four response was imminent.
A case is described of a 32-year-old woman who showed signs of injury to the left axillary nerve after lumbar spine surgery. This rare complication is reviewed and the possible mechanisms of injury are discussed.