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Biomedical subjects

S J Keens

Publications and source records attributed to S J Keens.

7 recordsLinked to original sources
PubMed1990

IV fluids during surgery.

During an attempt to measure renal function during operation in six patients undergoing major abdominal surgery involving intestinal resection and blood loss in excess of 300 ml, it became apparent that the conventional recommendation for i.v. crystalloid fluid of 5-10 ml kg-1 h-1 was not sufficient to maintain cardiovascular stability and urine output, but a volume of 15 ml kg-1 h-1, given to a subsequent six patients, was adequate. Administration of low sodium (glucose) solutions also produced biochemical abnormalities of a severity not documented previously. A survey of the published literature on volumes of crystalloid fluids used supports the contention that, during major surgery, crystalloid requirements may be of the order of 10-15 ml kg-1 h-1 rather than 5-10 ml kg-1 h-1.

Abdomen↗
PubMed1987

Neostigmine in the antagonism of the action of atracurium.

Antagonism of atracurium-induced neuromuscular blockade with neostigmine (one or two doses of 2.5 mg) was compared, using electromyography, with spontaneous recovery. Two levels of blockade were studied, one in which the initial response of the train-of-four has reached 10% of control and the other 50% of control. Adequate recovery was considered to be present when the ratio of the fourth response to the first (train-of-four ratio) had reached 70%. Neostigmine always accelerated recovery and "neostigmine block" was not detected. This acceleration of recovery after neostigmine was most marked with the greater degree of blockade, but two doses of neostigmine were no more effective than one. Spontaneous recovery to the train-of-four ratio of 70% was slow, in the order of 1 h after an initial dose of 0.5 mg kg-1 and 45 min after incremental doses of 0.2 mg kg-1. It is concluded that antagonism of atracurium with one dose of neostigmine is usually desirable, that two doses are unnecessary, and that spontaneous recovery is slower than is generally realized.

Atracurium↗
PubMed1987

Potentiation of the neuromuscular blockade produced by alcuronium with halothane, enflurane and isoflurane.

The potentiation of alcuronium by halothane, enflurane and isoflurane was investigated using electromyography. In the first study, cumulative dose-response curves were constructed in four groups of 10 patients anaesthetized with one of the inhalation agents and nitrous oxide, or with fentanyl and droperidol (control). All three agents reduced the ED50 of alcuronium; the effect was marked with isoflurane (P less than 0.005) but less so with halothane (P less than 0.05) and enflurane (ns). In the second part of the investigation, designed primarily to test the duration of action of alcuronium with each agent, a single bolus dose of alcuronium 0.2 mg kg-1 was given to four similar groups (n = 5). The duration of action was significantly prolonged by enflurane (P less than 0.01) and isoflurane (P less than 0.05), but not by halothane. The possible reasons for this are discussed.

Action Potentials↗
PubMed1986

Carcinoid syndrome with myasthenia gravis. An unusual and interesting case.

The anaesthetic management of a patient suffering from carcinoid syndrome and myasthenia gravis is described including the successful treatment of a carcinoid attack with intravenous aprotonin. The differences between myasthenia gravis and the myasthenic (Eaton-Lambert) syndrome are considered and the rationale for the choice of vecuronium as the muscle relaxant is discussed.

Action Potentials↗