A dose-ranging study of rapacuronium in pediatric patients.

BACKGROUND: The aim of this study was to determine the dose or doses of the new rapid-onset, short-acting, neuromuscular blocking drug rapacuronium that would provide satisfactory conditions for tracheal intubation at 60 s in infants and children. METHODS: Sixty-five infants (< 1 yr), 51 younger children (1-6 yr), and 49 older children (7-12 yr) were studied. Anesthesia was induced with thiopental-nitrous oxide-oxygen. Tracheal intubation was attempted 60 s after administration of one of five doses of rapacuronium (0.5, 1.0, 1.5, 2.0, or 2.5 mg/kg) and intubating conditions were assessed using a four-point scale. Following tracheal intubation, anesthesia was maintained with nitrous oxide-oxygen and alfentanil (12.5-50 microg/kg) as necessary. Neuromuscular transmission was monitored in an uncalibrated fashion using an acceleromyograph. RESULTS: Intubating conditions were good or excellent at 60 s in all infants after doses of 1.5 mg/kg or more and in all younger and older children after doses of 2.0 mg/kg or more. The duration of action of rapacuronium was dose- and age-dependent. Mean times to reappearance of the third twitch of the train-of-four (TOF; T3) were less than 10 min in infants at doses of 1.5 mg/kg or less and in younger and older children at doses of 2.0 mg/kg or less. Recovery of T3 after 1.0-2.0 mg/kg rapacuronium was significantly slower in infants compared with younger (P = 0.001) and older (P = 0.02) children. Five adverse experiences were related to rapacuronium administration: Bronchospasm (two instances), tachycardia (one instance), and increased salivation (two instances). None were serious. CONCLUSIONS: Doses of 1.5 and 2.0 mg/kg rapacuronium can produce satisfactory intubating conditions at 60 s in anesthetized infants and children, respectively, and are associated with a short duration of action.

Dose-response, time-course of action and recovery of rocuronium bromide in children during halothane anaesthesia.

Two groups of children, aged 1-4 years (n = 28) and 5-10 years (n = 28), respectively, received at random one of four doses of rocuronium (0.12, 0.17, 0.22 or 0.27 mg kg-1). When maximum block was obtained, further rocuronium to a total dose of 0.5 mg kg-1 was given. At a spontaneous T1 recovery of 25% the block was reversed with atropine and neostigmine in half the patients. The remainder were allowed to recover spontaneously. There was no difference in potency in the two age groups. An ED50 of 0.2 mg kg-1 was estimated. The estimates of ED50 were model-dependent of approximately 0.32 mg kg-1. The maximum block was found significantly higher in the younger age group (99.0 +/- 1.5% (mean +/- SD)) as compared to the older group (97.5 +/- 2.3%), and the clinical duration was also longer (16.6 +/- 5.3 min vs. 13.3 +/- 3.8 min), respectively. There was no significant difference between the two age groups in duration90 (26.9 +/- 6.5 min, 22.5 +/- 6.7 min, respectively) and duration0.7 (27.6 +/- 6.0 min, 24.9 +/- 7.9 min, respectively). Recovery time25-75, recovery time25-90, but not recovery time25-0.7 were found significantly longer in the 1-4 year group as compared to the times in older children. Neostigmine administration reduced recovery time by approximately half to two-thirds. MAP was not influenced by rocuronium. Following the injection of rocuronium in the younger age group there was a 15% increase in heart rate compared to a 10% increase in the age group 5-10 years.

[Cognitive function of geriatric ophthalmology patients after local and general anesthesia]. / Untersuchung der kognitiven Funktion bei geriatrischen ophthalmologischen Patienten nach Lokal-bzw. Allgemeinanästhesie.

Since there will be an increase in the number of geriatric patients who undergo surgery and anesthesia over the next few years, studies comparing the effects of general and local anesthesia on cognitive functioning in elderly persons are mandatory. One hundred eleven ophthalmological patients, all over the age of 64 years, were assessed preoperatively, on the first and on the fourth postoperative day using a battery of standardized cognitive tests. Of the initial sample, 47 patients undergoing local and 54 undergoing general anesthesia completed the assessment. The performance of the patients in six tests did not change perioperatively. In both anesthesia groups, two tests revealed a cognitive deficit postoperatively, which only became evident on the first postoperative day. The two other tests showed a significant difference between the two anesthesia groups on the first postoperative day. The performance of patients with general anesthesia decreased transiently and returned to the initial levels within 3 days. We conclude from our results that postoperative cognitive deficits may occur in geriatric patients. However, general anesthesia poses no more risk to cognitive function than local anesthesia.

[The importance of neuromuscular monitoring during anesthesia for neuroradiologic diagnosis]. / Bedeutung des neuromuskulären Monitorings bei Anästhesien zur neuroradiologischen Diagnostik.

Muscle relaxants are essential in anaesthesia for neuroradiological diagnosis. In addition, neurosurgical and neurological patients often face, because of their basic illness, respiratory danger, which can increase postoperatively through the use of muscle relaxants during anaesthesia. Because of their pharmacodynamic properties and side-effects, muscle relaxants must be clearly differentiated from one another and used selectively for the different phases of anaesthesia-intubation, calmness during examination and recovery from neuromuscular block with extubation. During planned extubation in particular, no residual relaxation or danger of recurarization must exist during the recovery stage from neuromuscular block. For investigations with planned extubation, only the muscle relaxants atracurium and vecuronium with their medium-long effect should be applied. A high degree of safety is provided by neuromuscular block and especially in the recovery phase. Using relaxometers it is possible to determine individual relaxant requirements, avoid under- and overdoses, carry out an antagonism at the correct time and prevent residual relaxation situations so that respiratory insufficiency can be reliably excluded.

Marked decrease in arterial oxygen tension associated with continuous intravenous nifedipine administration.

Intravenous nifedipine was administered to treat arterial hypertension in a 54-year-old woman presenting for removal of a meningioma. A marked decrease in arterial oxygen tension occurred during the nifedipine infusion. Inhibition of hypoxic pulmonary vasoconstriction by nifedipine is discussed.

[Cannulation of the axillary artery in continuous blood pressure monitoring and blood gas analysis]. / Kanülierung der Arteria axillaris zur kontinuierlichen Blutdruckmessung und Blutgasanalyse.

Catheterisation of the axillar artery for the control of blood pressure and blood gases is described. The advantages over puncturing of small arteries consist in the lower risk of thromboembolic complications and the greater accuracy in blood pressure measurement. Compared with the a. femoralis, the a. axillaris offers the advantages of better intraoperative accessibility, lower risk of contamination and better mobility of the patient. Out of 120 patients who received an a. axillaris catheter preoperatively or in the intensive-care ward for control purposes, complications occurred in 12 cases (haematomas after decannulation, disturbed sensitivity, thrombus at the vascular wall, kinking and obstruction of the catheter), which, however, did not give rise to any clinical sequels.