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Biomedical subjects

D Ostergaard

Publications and source records attributed to D Ostergaard.

At least 37 records · Page 2Linked to original sources
PubMed1992

Influence of plasma cholinesterase activity on recovery from mivacurium-induced neuromuscular blockade in phenotypically normal patients.

The significance of plasma cholinesterase (pChe) activity for the duration of action of mivacurium in phenotypically normal patients was evaluated in 35 patients during neurolept anaesthesia. The response to train-of-four nerve stimulation was recorded using a Myograph 2000. Ten patients with normal pChe (Group I) and five patients with decreased pChe activity (Group 2) were given a small test dose of mivacurium 0.03 mg kg-1. Mivacurium 0.1 mg kg-1 was administered following spontaneous recovery from the first dose. The mean suppression of the height of the first (T1) of the train-of-four responses following mivacurium 0.03 mg kg-1 patients with normal and decreased enzyme activity was 40% and 56%, respectively, and the mean T1 suppression after mivacurium 0.1 mg kg-1 was 100% in both groups. The times to different levels of twitch height recovery following the 0.1 mg kg-1 dose did not differ between the two groups of patients. Another 20 patients with normal or decreased pChe activity (Group 3) were given mivacurium 0.2 mg kg-1. In this group the time to maximum block was 1.4 min (1.0-4.0) mean (range) and the time to reappearance of the T1 response was 15.0 min (7.4-22.7) (range). An inverse relationship was found between the patients' pChe activity and the time to first response. It is concluded that mivacurium is short-acting in patients with normal pChe phenotype and normal to low-normal pChe activity. No patient with very low pChe activity was included in the study. A prolonged response to mivacurium may, however, be expected in these patients.

Anesthesia Recovery Period↗
PubMed1991

Pretreatment with pancuronium before suxamethonium administration in patients heterozygous for the usual and the atypical plasma cholinesterase gene.

The object of this study was to investigate whether pretreatment with pancuronium before i.v. injection of suxamethonium could cause prolonged neuromuscular blockade in patients heterozygous for the usual and the atypical plasma cholinesterase gene (E1uE1a). Forty-three patients, 23 with genotype E1uE1a and 20 with normal genotype (E1uE1u), were pretreated with pancuronium 0.01 mg.kg-1 followed by suxamethonium 1.5 mg.kg-1, and received either neurolept anaesthesia or halothane anaesthesia. Seven patients (E1uE1a) were given suxamethonium 1.5 mg.kg-1 without pretreatment. The duration and type of neuromuscular block were evaluated using train-of-four (TOF) nerve stimulation. Type of anaesthesia did not significantly influence the results. The duration of block following pretreatment was significantly longer in heterozygous patients than in normal patients. Time to 90% twitch height recovery was 10.7 +/- 1.2 min (mean +/- s.d.) in genotypically normal patients, and 18.0 +/- 4.2 min in patients with genotype E1uE1a. Pretreatment with pancuronium caused a significantly slower recovery of the TOF ratio (phase II block). Thus, a TOF ratio of 0.7 was always reached within 13 min in genotypically normal patients. In genotypically abnormal patients, the same TOF ratio was reached within 20 min in all but three patients. In these three patients time to 90% twitch height recovery was prolonged (18-31 min), and TOF ratio did not return to normal, but stabilized at about 0.35, 0.50, and 0.65, respectively. Injection of edrophonium restored normal neuromuscular function in 10 min. It is concluded that in patients heterozygous for the usual and the atypical gene, pretreatment with pancuronium in combination with an increased dose of suxamethonium may cause a phase II block and thus a prolonged neuromuscular block.

Adult↗
PubMed1990

Reversal of intense neuromuscular blockade following infusion of atracurium.

In order to evaluate reversal time from very intense neuromuscular blockade caused by a continuous infusion of atracurium, the time course of neostigmine induced reversal from different levels of neuromuscular blockade was evaluated using the post-tetanic count (PTC) and the train-of-four (TOF) in 30 patients anesthetized with nitrous oxide, fentanyl, and thiopental. Reversal time (time from administration of neostigmine at different PTC levels to a TOF ratio of 0.7) was found to depend upon the degree of blockade at the time of reversal. Median reversal time from a PTC of 1-2, 3-4, 5-6, 7-8, 9-10, 11-12, and greater than 13 (but less than 10% twitch height) to a TOF ratio of 0.7 was 31, 23, 19, 18, 14, and 13 min, respectively. Spontaneous recovery from PTC level of 1-2, when atracurium infusion was stopped, to a PTC level at which antagonism was induced and reversal time were both correlated to the square root of the PTC. Total recovery time (spontaneous recovery plus reversal time) was not shortened by an early injection of neostigmine. It is concluded that neostigmine administration during intense neuromuscular blockade following atracurium infusion does not shorten total recovery time and offers no clinical advantages.

Adult↗
PubMed1989

Double burst stimulation (DBS): a new pattern of nerve stimulation to identify residual neuromuscular block.

We present a new pattern of nerve stimulation--double burst stimulation (DBS)--to detect residual neuromuscular block manually. The DBS consists of two short lasting, 50-Hz tetanic stimuli or bursts separated by a 750-ms interval. The response to this pattern of stimulation is two single separated muscle contractions of which the second is less than the first during nondepolarizing neuromuscular blockade. The ability to identify fade manually at different train-of-four (TOF) ratios was compared in four DBS patterns in which different numbers of impulses in the individual bursts were combined. The DBS with three impulses in each burst (DBS3,3) was considered to be the most sensitive and the least painful and thus most suitable for clinical use. The degree of fade in TOF and DBS3,3 was almost identical at any level of blockade (correlation coefficient 0.96), and the major post-DBS3,3 effect was a depression of the first twitch in TOF lasting less than 15 s. It is concluded that the DBS is more sensitive than the TOF in manual detection of residual block.

Adult↗
PubMed1989

Clinical recovery and train-of-four ratio measured mechanically and electromyographically following atracurium.

Indices of clinical recovery were compared with mechanically (adductor pollicis muscle) and electromyographically (first dorsal interosseal muscle) recorded train-of-four (TOF) ratios during antagonism of atracurium blockade in 23 healthy neurolept anesthetized patients. Clinical recovery was evaluated from the ability to lift the head, sustain headlift for 5 or 10 s, protrude the tongue, open the eyes, and the presence of ptosis of the eyelids. In all patients the mechanical TOF ratio was recorded. In 17 patients TOF ratios based on measurements of the potential area and the amplitude of the major negative deflection of the compound EMG response were recorded as well. At each TOF ratio interval of 0.05 from a TOF ratio of 0.5-0.85, the number of patients being able to perform the individual tests was recorded. Further, the mechanical TOF ratio during recovery was compared with the EMG TOF ratios. Headlift could not be sustained for 5 s in any patient at a TOF ratio of 0.5, whether recorded mechanically or by EMG, and TOF ratio had to recover to 0.8 before all patients could sustain headlift for 5 s. All patients could open the eyes and protrude the tongue at a TOF ratio of 0.65, and ptosis remained present during the entire testing period. There was no statistically significant difference between the mechanical and the EMG methods with regard to the TOF ratios at which the tests could be performed. During recovery a linear relationship was found between mechanical TOF ratios and the square root of the EMG TOF ratios.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Half-life of plasma cholinesterase.

The half-life of plasma cholinesterase (acylcholine acylhydrolase EC 3.1.1.8) was determined in three patients homozygous for the atypical gene for plasma cholinesterase by measuring the rate of disappearance of enzyme activity following intravenous injection of concentrated human cholinesterase. Half-life values of 10.9, 11.1, and 11.3 days were estimated. The distribution volume was estimated to be 18.0, 18.2, and 13.8% of body weight, respectively.

Adult↗
PubMed1987

A new infusion design for atracurium and vecuronium.

An infusion technique, designed to reduce the duration of period of no response to nerve stimulation following atracurium (Group I) and vecuronium (Group 2), was studied in 30 patients during neurolept anaesthesia. For intubation a combination of a small bolus injection of the relaxant (ED50) and a continuous infusion were administered. The tactile response to nerve stimulation was used to quantify the degree of relaxation and to adjust the speed of infusion. On the other arm the mechanical twitch was recorded blindly for control. Good to excellent intubation conditions were obtained in 4.3 min with atracurium and in 4.0 min with vecuronium. The total dose given for intubation was 0.36 mg kg-1 atracurium (0.24-0.49 mg kg-1) and 0.064 mg kg-1 vecuronium (0.046-0.084 mg kg-1). The period of no response was zero in seven patients in Group I and in four patients in Group 2. In the remaining patients in Group I the period of no response ranged from 5.0-25.0 min, median 10.9 min, and in Group 2 from 2.5-15.6 min, median 9.5 min. At the time of extubation the train-of-four ratio was 0.71 and 0.72 in Group I and 2, respectively. It is concluded that it is possible to achieve a stable, adjustable, and easily reversible block with this technique, even during surgery of short duration.

Adult↗
PubMed1986

The influence of fentanyl on the cardiovascular effect of suxamethonium.

The influence of fentanyl on the cardiovascular effect of a single dose of suxamethonium was evaluated during thiopentone N2O/O2 anaesthesia. Sixty adult patients were randomly allocated to three groups. In one group (control group) no fentanyl was given. In two groups fentanyl 0.002 mg/kg and 0.004 mg/kg, respectively, was given before induction of anaesthesia. Three minutes after the injection of suxamethonium 1 mg/kg, both heart rate (HR) and mean arterial pressure (MAP) in the two groups receiving fentanyl were significantly lower than in the control group. However, the absolute changes were small and no dose-related effect was seen. An estimation of the change in HR following suxamethonium was made using as predictors initial HR before induction of anaesthesia, age, sex, and the injection of fentanyl. The higher the initial HR, the greater was the chance of a decrease in HR following suxamethonium. Injection of fentanyl lowered the threshold HR above which a decrease was to be expected following injection of suxamethonium. This effect was most pronounced among the younger patients. It is concluded that injection of fentanyl potentiates the decrease in HR sometimes seen after a single dose of suxamethonium and that this effect is influenced by HR before induction of anaesthesia and by age of the patient.

Adult↗
PubMed1985

Edrophonium and neostigmine for reversal of the neuromuscular blocking effect of vecuronium.

The effect of edrophonium for reversal of the non-depolarizing neuromuscular blockade produced by a continuous infusion of vecuronium was compared to that of neostigmine in 20 adult patients during neurolept anaesthesia. When antagonism was attempted at 10% twitch height recovery, reversal time to a train-of-four ratio of 0.7 was significantly shorter following neostigmine 0.04 mg/kg than after edrophonium 0.75 mg/kg (9.8 min and 18.7 min, respectively) but the same after edrophonium 1.5 mg/kg (10.3 min). There was no statistically significant difference in reversal time between neostigmine 0.04 mg/kg given at 10% twitch height and edrophonium 0.75 mg/kg given at 25% twitch height recovery (6.0 min). Additional doses of atropine were necessary following edrophonium 1.5 mg/kg.

Adult↗