Intermediate-acting Muscle Relaxant Research Articles

Postoperative neuromuscular block following atracurium or alcuronium in children

Postoperative neuromuscular block (NMB) was evaluated in 60 children who received randomly either atracurium or alcuronium to induce and maintain an 85-95 per cent NMB during balanced anaesthesia. The EMG-monitor was turned away from the anaesthetist 10-15 min before the end of surgery. The average NMB was comparable between the groups at the time of reversal with neostigmine 50 micrograms.kg-1 (84 +/- 9 per cent, mean +/- SD) as were the NMB and the train-of-four ratio when the tracheas were extubated on a clinical basis (32 +/- 20 per cent and 50 +/- 18 per cent, respectively). Patients who had been paralyzed with atracurium arrived at the recovery room earlier and on arrival had greater train-of-four ratios than the patients paralyzed with alcuronium (P less than 0.01). Time to a train-of-four ratio of greater than 90 per cent was significantly shorter in the atracurium group (10 +/- 5 min vs 26 +/- 15 min, P less than 0.001). Thus, an intermediate-acting muscle relaxant offers a safer recovery profile of the NMB than a long-acting muscle relaxant in paediatric patients.

Clinical uses of intravenous anesthetic and analgesic infusions.

Renewed interest in i.v. anesthetic techniques has resulted from the availability of more rapid and shorter-acting i.v. drugs. With recent advances in the area of infusion pump technology, it has become easier to administer i.v. anesthetics and analgesics by continuous infusion techniques. The newer sedative-hypnotic (midazolam, propofol) and analgesic (sufentanil, alfentanil) drugs are better suited pharmacologically to continuous administration techniques than the traditional i.v. agents because they can be more accurately titrated to meet the unique and changing anesthetic needs of the individual patient. With the newer sedative and analgesic drugs, it is now possible to administer i.v. anesthetics in a titrated manner analogous to that which is possible when volatile anesthetics are used. In this way, the drug infusion rate is varied depending on the patient's responses to noxious surgical stimuli. In titrating i.v. drug infusions, consideration must also be given to the age of the patient, pre-existing disease states, potential drug interactions, and proximity to the end of the operative procedure. The availability of rapid and short-acting i.v. drugs like alfentanil and propofol, as well as intermediate-acting muscle relaxants makes it possible to employ total intravenous anesthetic techniques during general surgery. Many non-sedative and non-analgesic i.v. drugs are being investigated in anesthesia for use by continuous infusion techniques, e.g., muscle relaxant, and local anesthetics. Several recent studies have demonstrated the efficacy of continuous infusions of local anesthetics for obstetrical analgesia. The use of continuous local anesthetic infusions makes it possible to achieve improved analgesia (i.e., a more constant degree of analgesia) with lower doses. Improved delivery systems for administering i.v. drugs will make it easier to use continuous infusion techniques in the future. With continued progress in the development of infusion devices and i.v. drugs designed for continuous administration, the use of intravenous anesthetic techniques will become more widespread. In the near future, infusion pumps will likely become standard equipment on all anesthesia machines and anesthesiologists should find these techniques easier to use in their clinical practices.