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Biomedical subjects

L I Eriksson

Publications and source records attributed to L I Eriksson.

46 records · Page 3Linked to original sources
PubMed1992

Atracurium-induced neuromuscular block in the isolated arm.

A modification of the isolated arm technique was applied in 10 females under opioid-based i.v. anaesthesia for comparison of the offset of an atracurium-induced neuromuscular block in an isolated arm to an arm with maintained circulation. The neuromuscular blocking effect of a bolus dose of atracurium 0.5 mg.kg-1 was measured bilaterally using the integrated adductor pollicis EMG response (integrated T1 EMG response in % of baseline value and T4/T1 ratio) after bilateral ulnar nerve train-of-four (TOF) stimulation. At 10% T1 recovery, one arm was isolated from the general circulation for 20 min by means of a tourniquet cuff (isolated arm), while normal circulation was maintained in the other arm (control arm). In both arms, the TOF response, peripheral skin temperature, mixed peripheral venous pH and plasma concentrations of atracurium and laudanosine were then measured and compared. Core and peripheral skin temperatures in both arms remained stable and normal throughout the study, and mixed peripheral venous pH stayed within physiological limits in both arms in all subjects. In the isolated arm, recovery of the neuromuscular block was markedly delayed compared to the control arm, the integrated EMG T1 response and TOF ratio being significantly reduced in the isolated arm after 20 min of isolation. The decline in plasma concentration of atracurium was less in the isolated arm than in the control arm, whereas laudanosine levels increased in the isolated and decreased in the control arm. Normal peripheral circulation is of major importance for termination of an atracurium-induced neuromuscular block.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia Recovery Period↗
PubMed1991

Twitch tension and train-of-four ratio during prolonged neuromuscular monitoring at different peripheral temperatures.

In eight healthy patients, the influence of the train-of-four (TOF) response of prolonged neuromuscular monitoring and of different peripheral temperatures was studied during normal core temperature. Anaesthesia was induced and maintained with midazolam-fentanyl and a 70/30% mixture of nitrous oxide and oxygen. The mechanical TOF response of the adductor pollicis muscle (twitch tension and TOF ratio), was recorded simultaneously in both hands using supramaximal TOF stimulation of the ulnar nerve at the wrist. One arm was kept normothermic. The other arm was cooled using cold infusions and cold packings. Skin, muscle and core temperatures were continuously measured. In the normothermic arm (skin temperature greater than 32.0 degrees C), the twitch tension and TOF ratio were unchanged following 130-230 min of continuous nerve stimulation. In the hypothermic arm the twitch tension and TOF ratio showed only minor variations above a skin temperature of 32.0 degrees C (corresponding to a mean muscle temperature of 34.5 +/- 0.3 degrees C). Below a skin temperature of 32.0 degrees C a progressive decrease in TOF response was recorded. A linear relationship was found between skin temperature and TOF response as well as between muscle temperature and TOF response. At a skin temperature of 27.0 degrees C (corresponding to a mean muscle temperature of 30.8 +/- 0.4 degrees C), an approximate 20% reduction in twitch tension and a 10% decrease in TOF ratio were recorded with a considerable interindividual variation. We conclude that prolonged TOF nerve stimulation does not change the mechanical twitch response in patients with a normal central and peripheral temperature. A peripheral skin temperature below 32.0 degrees C with sustained and normal body temperature is, however, associated with changes in both twitch tension and TOF ratio that may be a source of error when evaluating neuromuscular function.

Aged↗
PubMed1991

The effect of peripheral hypothermia on a vecuronium-induced neuromuscular block.

Seven healthy patients were investigated during midazolam-fentanyl nitrous oxide-oxygen anaesthesia. The mechanical twitch response of the adductor pollicis muscle was recorded simultaneously during bilateral supramaximal train-of-four (TOF) stimulation of the ulnar nerves at the wrist. Intense neuromuscular block was evaluated using the post-tetanic count (PTC) method. Core temperature and the peripheral skin temperature of one arm were kept normal and stable. Following cooling of the other arm to a peripheral hand skin temperature of 27 degrees C, vecuronium was administered in a bolus dose of 0.05 mg.kg-1 followed by maintenance doses of 0.02 mg.kg-1. In the hypothermic and the normothermic arm the onset time following the bolus dose was 180 +/- 40 (mean +/- s.d.) seconds and 140 +/- 30 s, respectively, the duration of action was 26.4 +/- 4.5 and 16.5 +/- 4.0 min and the recovery time was 265 +/- 90 and 130 +/- 60 s (P less than 0.01). The time course of action following maintenance doses showed a similar marked difference between the hypothermic and the normothermic arm. In the normothermic arm a close correlation was found between the number of post-tetanic twitches and the time to first response to TOF stimulation. In contrast, in the hypothermic arm the number of post-tetanic twitches showed great variation with a poor correlation to the duration of intense neuromuscular block. It is concluded that the time course of action of a vecuronium-induced neuromuscular block is markedly prolonged during peripheral hypothermia and intense neuromuscular block cannot reliably be assessed using the PTC method at low peripheral temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed1990

Use of post-tetanic count in assessment of a repetitive vecuronium-induced neuromuscular block.

In order to evaluate the use of the post-tetanic count (PTC) method during repetitive administration of vecuronium, we studied 20 patients allocated randomly to one of two groups: 10 patients received droperidol-fentanyl anaesthesia (control group); 10 other patients were given droperidol-fentanyl anaesthesia modified subsequently by addition of 0.5% isoflurane (isoflurane group). Before tracheal intubation, a bolus dose of vecuronium 0.08 mg kg-1 was given i.v. followed by repeated doses of 0.03 mg kg-1. The twitch response of adductor pollicis was recorded after supramaximal stimulation of the ulnar nerve at the wrist using a Myograph 2000 neuromuscular transmission analyser. In the control group, a close correlation was found between PTC and time to first reaction to train-of-four (TOF) nerve stimulation. This relationship was unchanged when comparing the bolus dose and each of eight consecutive maintenance doses. Further, the degree and the duration of intense block were unchanged after each of the eight maintenance doses. In the isoflurane group, the relationship between PTC and time to first reaction to TOF stimulation remained unchanged after addition of isoflurane. However, isoflurane caused a significant prolongation of the duration of intense block and a corresponding lower PTC in all patients. We conclude that PTC is a reliable method to evaluate intense neuromuscular block caused by vecuronium, even after repetitive administration of the drug and in combination with 0.5% isoflurane.

Adult↗
PubMed1990

The influence of 10 mg and 20 mg of bambuterol on the duration of succinylcholine-induced neuromuscular blockade.

Bambuterol is an inactive prodrug which is enzymatically cleaved by plasma cholinesterase to yield the active compound, terbutaline. This catalytic process is accompanied by a selective inhibition of plasma-cholinesterase, the enzyme also necessary for the break-down of succinylcholine. We therefore studied the possible effect of bambuterol on succinylcholine-induced neuromuscular blockade in a double-blind fashion in patients undergoing surgery under general anaesthesia. Of the 39 patients studied, 13 patients had 10 mg of bambuterol, 12 had 20 mg and 14 were given placebo 10-16 h prior to anaesthesia. Succinylcholine 1 mg.kg-1 bw was administered after induction of anaesthesia. Following supramaximal train-of-four stimulation of the ulnar nerve, the tension developed in the adductor pollicis muscle was measured. Onset time and the durations of action (times to 10%, 25%, 75% and 90% recovery of the first twitch of the train-of four response) were recorded. The mean recovery times were prolonged 30-50% in patients who had received 10 or 20 mg of bambuterol as compared with placebo. It is concluded that a prolonged duration of action of succinylcholine can be expected in patients being treated with bambuterol.

Adult↗
PubMed1989

The influence of 0.5% isoflurane on a vecuronium-induced neuromuscular blockade.

The influence of adding 0.5% isoflurane to a narcotic-based anaesthesia on the duration of effect and recovery time after repetitive administration of vecuronium was studied in ten healthy patients. The twitch response in the adductor pollicis muscle was recorded after supramaximal train-of-four (TOF) stimulation of the ulnar nerve at the wrist. Prior to endotracheal intubation a bolus dose of vecuronium (0.08 mg/kg b.w.) was given. During surgery repeated injections of vecuronium (0.02 mg/kg b.w.) were administered at a TOF ratio of 0.25. Hand-skin temperature, systolic blood pressure, end-tidal CO2 and isoflurane concentrations were continuously monitored. Before and after 90 min administration of isoflurane, the duration of effect was 21 +/- 4 and 24 +/- 5 min (mean +/- s.d., P less than 0.05) respectively. Corresponding recovery times were 270 +/- 60 and 280 +/- 70 s (n.s.). Skin temperature remained unchanged and systolic blood pressure showed only minor variations. The addition of 0.5% isoflurane to a narcotic-based anaesthesia causes a moderate increase in duration of effect but no change in recovery time from a repetitive vecuronium-induced neuromuscular blockade of 0.02 mg/kg.

Adolescent↗
PubMed1989

Clinical experience with atracurium during prolonged anaesthesia.

The pharmacodynamic properties of repeated injections of atracurium were studied in twenty-two patients. A control group received narcotic-based anaesthesia while another group received the same narcotic-based anaesthesia subsequently modified by the addition of 0.5% isoflurane. The twitch response of the adductor pollicis muscle was recorded after train-of-four (TOF) stimulation of the ulnar nerve at the wrist. Duration of effect and recovery time were measured. A bolus dose of atracurium (0.5 mg/kg b.w.) was given for tracheal intubation and maintenance doses of 0.2 mg/kg b.w. were given during anaesthesia at a TOF ratio of 0.25. Mean duration of anaesthesia was 7.5 hours (range 3-19). In the control group mean duration of effect and mean recovery time remained unchanged (six doses studied). A noteworthy inter-individual variation was found. In the isoflurane group mean duration of effect increased from 36.1 (SD 6.3) minutes to 42.2 (SD 8.1) minutes (P less than 0.05) following the addition of isoflurane. Corresponding recovery times remained unchanged. We conclude that during repeated administration of atracurium during narcotic-based anaesthesia, each patient shows a constant interval between requirements for maintenance doses of atracurium of 0.2 mg/kg b.w. Addition of 0.5% isoflurane causes a moderate prolongation of the duration of effect, but recovery time remains unchanged.

Adult↗
PubMed1988

Experience with vecuronium during long-lasting surgery.

Our knowledge of the possible cumulative properties of vecuronium is limited. Previous studies have shown a tendency towards an increased duration of effect, a slightly prolonged recovery time, as well as an increased variation in duration of effect. We have studied 15 patients scheduled for middle-ear surgery. During i.v. N2O-O2 anaesthesia the twitch response of the adductor pollicis muscle was recorded after supramaximal stimulation of the ulnar nerve at the wrist. Prior to tracheal intubation a bolus dose of vecuronium was given (0.08 mg/kg body weight). During surgery supplementary doses of 0.02 mg/kg body weight were given at a train-of-four (TOF) ratio of 0.25. The duration of effect (DUR-IT-25) and recovery time from a TOF ratio of 0.10 to 0.25 (Recovery-IT-10-25) were recorded. When comparing 10 iteration doses, the mean DUR-IT-25 in the 15 patients studied showed only minor variations (n.s.). Each patient had a near constant interval between the iteration doses; however, a noteworthy variation between individuals was found. Recovery-IT-10-25 was 250 +/- 80 (mean +/- s.d.) 240 +/- 80 and 260 +/- 80 s comparing the second, sixth and tenth iteration doses, respectively. In conclusion, the duration of effect varied considerably between patients. Each patient showed, however, a near constant iteration interval and a recovery time with only small variations. This indicates that cumulation is unlikely to exist following repetitive administration of vecuronium of 0.02 mg/kg body weight.

Adolescent↗
PubMed1986

Overuse and distorsion soccer injuries related to the player's estimated maximal aerobic work capacity.

Fourty senior male soccer players were selected for this study. Before the season, each subject performed an exercise test, and the maximal capacity of oxygen uptake was estimated according to Astrand and Rhyming. The exercise test was repeated in 25 subjects 6 months later. The subjects were then ranked according to their estimated maximal capacity of oxygen uptake (estimated VO2 max) at the first test and allocated into one of three groups of similar size. During the season, all new injuries were examined and registered by an orthopaedic surgeon, and the subjects were allocated into one of three groups (overuse injuries, distorsion injuries, and other injuries). There were significantly more overuse injuries among subjects with high estimated VO2 max, and the incidence of distorsion injuries tended to be lower among subjects with high estimated VO2 max. No correlation was found regarding the total incidence of injuries and estimated VO2 max. No significant difference in estimated VO2 max was registered between the tests before and after the season.

Athletic Injuries↗