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Biomedical subjects

L Lindgren

Publications and source records attributed to L Lindgren.

At least 181 records · Page 10Linked to original sources
PubMed1984

Effects of practolol and metoprolol on QT interval, heart rate and arterial pressure during induction of anaesthesia.

The effects of the selective beta 1-adrenergic receptor blocking agents, practolol with intrinsic sympathetic activity (ISA) and metoprolol without ISA, were studied on QT interval, heart rate, arterial pressure and cardiac arrhythmias during the induction of anaesthesia in 142 adults. In the control group, the QT interval was statistically significantly prolonged after thiopental, and the most marked prolongation occurred after suxamethonium. Neither practolol nor metoprolol alone affected the QT interval. Practolol 100 micrograms/kg i.v., but not 40 or 150 micrograms/kg i.v., almost completely reduced the prolongation of the QT interval after suxamethonium. In all doses of 20, 30 and 40 micrograms/kg i.v. metoprolol statistically significantly and dose-dependently reduced the prolongation of the QT interval after thiopental, suxamethonium and laryngoscopy, but the prolongation of the QT interval after intubation still occurred. Practolol and metoprolol alone statistically significantly reduced heart rate, but did not prevent the increase of heart rate after thiopental. The effects on arterial pressure were minimal. Neither practolol nor metoprolol prevented the cardiovascular intubation response. Ventricular ectopic beats after intubation occurred in 20% of the patients in the control group and their incidence ranged from 20 to 27% in the groups pretreated with practolol or metoprolol 20 micrograms/kg. In the groups pretreated with metoprolol 30 or 40 micrograms/kg, ventricular ectopic beats occurred in 5% and 8%, respectively. It is concluded that the selective beta 1-adrenergic receptor blocking agents practolol with ISA, and especially metoprolol without ISA, reduced the prolongation of the QT interval after suxamethonium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Metabolic and respiratory hydrogen ion effects on hypoxic pulmonary vasoconstriction.

Hypoxic pulmonary vasoconstriction (HPV) was studied in the ventilated-perfused rat lung in vitro. Respiratory acidosis and alkalosis were obtained by ventilating with 2, 7, or 10% CO2 (21% O2-balance N2). Metabolic acidosis and alkalosis were produced by the addition of 0.9 N NaHCO3 or 1 N lactic acid to the perfusate at constant PCO2. At each pH the pressor responses to 2 and 4% O2 were compared with the maximum pressor response (R%max) obtained with zero O2 and 5% CO2 at a normal pH (approximately 7.35). HPV was maximal when the [H+] was between 38 and 50 nM and was attenuated by changes of pH in either direction. Both respiratory and metabolic pH changes had similar effects. The combined linear regression equations were as follows: with 2% O2 the response to acidosis was R%max = 101.37 - 0.52 [H+] and to alkalosis was R%max = 2.03 [H+] - 3.85; with 4% O2 the response to acidosis was R%max = 56.88 - 0.3 [H+] and to alkalosis was R%max = 1.16 [H+] - 4.95. These effects were not due to changes of ionized calcium.

Animals↗
PubMed1983

Cardiovascular responses to enflurane induction followed by suxamethonium in children.

Induction of anaesthesia with enflurane 5 vol% plus 70% nitrous oxide in oxygen was followed by suxamethonium 1, 1.5 or 2 mg kg-1 i.v. and the cardiovascular changes studied in 58 children. The eyelash reflex disappeared in 44 +/- 1.2 (SEM)s and the venepuncture could be performed 1.8 +/- 0.05 (SEM) min after the start of enflurane anaesthesia. The increase in systolic arterial pressure after tracheal intubation was less marked after enflurane than after thiopentone (taken from an earlier study). Heart rate increased significantly after all doses of suxamethonium, but no cardiac arrhythmias were seen. The QT interval was significantly prolonged by enflurane (P less than 0.001), but remained unchanged after suxamethonium.

Anesthesia, Inhalation↗
PubMed1983

Effect of competitive myoneural blockade and fentanyl on muscle fasciculation caused by suxamethonium in children.

The effects of tubocurarine 0.06 mg kg-1, alcuronium 0.03 mg kg-1, pancuronium 0.01 mg kg-1, and fentanyl 1 or 2 micrograms kg-1 on the muscle fasciculations associated with suxamethonium were studied in 171 children undergoing otolaryngological surgery. The mean fasciculation index in all pretreatment groups was significantly smaller than in the control group. The most effective pretreatment was fentanyl 2 micrograms kg-1 followed, in order, by alcuronium, fentanyl 1 microgram kg-1, tubocurarine and pancuronium. The rate of the onset of the fasciculations after the injection of suxamethonium ranged from 8 s after pancuronium to 20 s after tubocurarine. There was evidence of respiratory depression in the children receiving fentanyl 2 micrograms kg-1 if the duration of anaesthesia was less than 30 min.

Child↗
PubMed1983

Pulmonary blood pressure and flow during atelectasis in the dog.

The purpose of the study was to measure the time course, direction, and magnitude of the hypoxic pulmonary vasoconstriction (HPV) response to atelectasis. Six dogs were anesthetized with pentobarbital. With the chest open, each lung was ventilated separately. Pulmonary blood flow was measured with electromagnetic flow probes. Pulmonary arterial, left atrial, and systemic arterial pressures were measured via indwelling catheters. The right lung was ventilated continuously with 100% O2, while the left lung was either ventilated with 100% O2 (control phase), unventilated (4 hours of atelectasis), or ventilated with a gas mixture containing 4% O2, 3% CO2, and 93% N2 (hypoxia phase). Left lung atelectasis resulted in a reduction of the per cent lung blood flow from 43 +/- 4% (mean +/- SE) to 25 +/- 7% at 15 min and to 12 +/- 1% at 60 min which persisted for the remaining four-hour period. The per cent left lung blood flow was significantly lower (8 +/- 1%) and the PaO2 significantly higher (356 +/- 38 mmHg) during the maximal response to atelectasis as compared to 15 min of hypoxic ventilation (23 +/- 5%; 211 +/- 21 mmHg). With atelectasis or hypoxic ventilation, pulmonary perfusion pressure was increased significantly from the control value of 7.9 +/- 0.8 mmHg to approximately 11 mmHg. The present study demonstrated that in the open chest model without systemic hypoxemia, the response to acute atelectasis is a regional increase in pulmonary vascular resistance which develops quickly (15 min) and is maximal by 60 min and is maintained thereafter. As a result, there is a sustained diversion of blood flow away from the atelectatic lung and a generalized increase of pulmonary perfusion pressure.

Animals↗
PubMed1983

Influence of mixed venous oxygen tension (PVO2) on blood flow to atelectatic lung.

The influence of mixed venous oxygen tension (PVO2) on blood flow to the atelectatic left lung was studied at normal and reduced cardiac outputs (CO) using extracorporeal veno-venous bypass in six pentobarbital anesthetized, mechanically ventilated dogs. Aortic and left pulmonary artery flows; airway, left atrial, central venous, pulmonary, and systemic arterial pressures; hemoglobin, arterial, and mixed venous blood gases were measured. The blood flow reduction observed in atelectasis was altered by the PVO2. Approximately 50% of blood flow was diverted away from atelectatic lung when PVO2 was low (24 +/- 2 mmHg) or normal (46 +/- 2 mmHg) (mean left lung blood flow [QL%] was 23.2 +/- 4.6% with low PVO2 and 19.0 +/- 3.4%, with normal PVO2). When PVO2 was increased to greater than 100 mmHg, diversion of blood flow away from atelectatic lung did not occur and QL% was nearly the flow expected for normoxic ventilated left lung (mean QL% = 40.4 +/- 5.9%). Shunt (QS/QT%) was significantly greater when PVO2 was high than when it was normal or low (mean QS/QT% = 51.7 +/- 5.6%, 31.0 +/- 3.1%, 26.0 +/- 3.4% with high, normal, and low PVO2, respectively). Mean PaO2 was significantly greater when PVO2 was high than when PVO2 was normal or low, despite the increase in QL% and QS/QT% (PaO2 = 327 +/- 25 mmHg, 220 +/- 32 mmHg, 115 +/- 21 mmHg with high, normal, and low PVO2, respectively). A 40% reduction in cardiac output significantly decreased transmural pulmonary artery pressure but did not affect PaO2, QS/QT%, or QL%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Prolongation of QT interval during induction of anaesthesia.

QT interval was studied in 156 adults and in 127 children during the induction of anaesthesia. Both in adults and in children, QT interval was prolonged statistically significantly after thiopentone 5 mg/kg and the most marked prolongation occurred after suxamethonium 1 to 1.5 mg/kg. In adults, d-tubocurarine 0.06 mg/kg, but not alcuronium 0.03 mg/kg or pancuronium 0.01 mg/kg, prevented statistically significantly the prolongation of the QT interval after suxamethonium 1.5 mg/kg. In children, all three muscle relaxants prevented statistically significantly the effect of suxamethonium 2 mg/kg and pancuronium also prevented the effect of thiopentone. The most common ECG changes were ventricular ectopic beats (VEB) which occurred in 26% of the adults and in 22% of the children who were not pretreated with the muscle relaxants. After pretreatment with d-tubocurarine, the incidence of VEB was 3% in both groups. In adults, alcuronium was as effective as d-tubocurarine in the prevention of VEB but in the alcuronium group supraventricular ectopic beats and junctional rhythm occurred in 6% and 9% of the patients, respectively. Pancuronium did not significantly prevent the incidence of VEB. On the basis of the present results, d-tubocurarine is the relaxant of choice for the prevention of the prolongation of QT interval as well as ECG changes during the induction of anaesthesia.

Adult↗
PubMed1981

Comparison of halothane and enflurane anaesthesia for otolaryngological surgery in children.

Halothane and enflurane were compared in 131 children undergoing adenoidectomy with or without tonsillectomy. Anaesthesia for adenoidectomy was induced with thiopentone or Althesin and for tonsillectomy with thiopentone. The response to surgery was minimal (0-5%) during both inhalation anaesthetics. During immediate recovery, respiratory depression was more profound after enflurane than after halothane. Both the i.v. and the inhalation anaesthetics had an influence on recovery. The total recovery scores (0-10) based on activity, respiration, heart rate, consciousness and colour improved most rapidly after Althesin + enflurane and most slowly after thiopentone + halothane on the adenoidectomy groups. In the tonsillectomy groups, the recovery scores were better after enflurane than after halothane. After both inhalation anaesthetics, the frequency of shivering ranged from 0 to 17%.

Adenoidectomy↗
PubMed1981

E.C.G changes during halothane and enflurane anaesthesia for E.N.T. surgery in children.

E.c.g. changes were compared in 152 children undergoing adenoidectomy of adenotonsillectomy (T + A) under halothane or enflurane anaesthesia. Junctional rhythm occurred in 4-16% of the children in adenoidectomy groups and in 11-33% in T + A groups. Bundle branch block occurred in 4% of the children anaesthetized with halothane, but not with enflurane and was particularly common in association with thiopentone and T + A operations; one patient had bifocal ventricular tachycardia. QT interval was prolonged compared with control after thiopentone (P less than 0.001) and thiopentone and suxamethonium (P less than 0.02). QT interval was not changed after Althesin with or without suxamethonium. Mean preanaesthetic QT interval (+/- SEM) was significantly prolonged (492 +/- 22 ms; normal 440 ms) in children showing aberrant conduction with chaotic rhythm, but normal (438 +/- 5 ms) when bundle branch block or junctional rhythm was present during halothane anaesthesia. QT interval was prolonged significantly in enflurane but not in halothane anaesthesia.

Adenoidectomy↗
PubMed1981

Perinatal mortality and differing socioeconomic status.

During the last decade the area served by the Public Maternity Hospital was significantly altered on some occasions. The perinatal mortality increased after the alteration of the district and the socioeconomic structure of the population was changed. The socioeconomic structure of the population has been defined and expressed as a socioeconomic factor. The obstetric care was mainly carried out without alteration. The object of the investigation was to determine if the exchange itself or the change in the socioeconomic situation of the population of the district was a cause of the increased perinatal mortality.

Female↗
PubMed1980

Comparison of oral triclofos, diazepam and flunitrazepam as premedicants in children undergoing otolaryngological surgery.

Triclofos 70 mg kg-1, diazepam 0.25 mg kg-1 and flunitrazepam 0.02 mg kg-1 all in combination with atropine 0.03 mg kg-1 were compared as oral premedicants in 128 children undergoing otolaryngological surgery in a double-blind study. All drugs provided good anxiolysis in children 5 yr and older. In children less than 5 yr, the effects of triclofos were superior to those of diazepam and flunitrazepam. There was a positive correlation between anxiolysis and the ease of induction of anaesthesia. In both age groups, flunitrazepam prevented the fasciculations caused by suxamethonium more effectively than did diazepam or triclofos. The preinduction heart rate after triclofos was greater than after the other drugs and its antisialagogue effect was superior. The mean volume of gastric contents was 0.4 ml kg-1 for all the patients with no statistically significant difference between the groups. The mean pH of gastric contents was 4.5 after triclofos and 2.2 after other drugs. The serum concentration of both benzodiazepines in the older age group was greater than in the younger age group.

Administration, Oral↗
PubMed1979

Comparison of I.M. pethidine, diazepam and flunitrazepam as premedicants in children undergoing otolaryngological surgery.

Pethidine 1 mg kg-1, diazepam 0.25 mg kg-1 and flunitrazepam 0.02 mg kg-1 i.m. wer compared as premedicants in a double-blind study in 145 children undergoing otolaryngological surgery. Both flunitrazepam and pethidine had an anxiolytic effect in the children of less than 5 yr whereas diazepam had little effect. All of the drugs were anxiolytic in the children aged 5 yr and older. Sleep following thiopentone was restless more often in the younger than in the older children. Cardiovascular responses to thiopentone and to tracheal intubation were most obvious following benzodiazepines in children of less than 5 yr. After anaesthesia 10--33% of the older children could not recall pictures shown to them before anaesthesia. Forty-five (+/-SD 13) min after injection, the concentration of diazepam in serum was similar in both age groups; after 90 min it decreased in the younger and increased in the older children. All concentrations of flunitrazepam were significantly greater in the older compared with the younger children.

Adolescent↗
PubMed1977

The influence of pressure upon the fetal head during labour.

In contracted pelvis, moulding of the skull bones is caused by the force of the amniotic fluid pressure and the resistance of the pelvis. In normal labour and abnormal uterine action the moulding of the skull bones is caused by the head to cervix pressure, as has been demonstrated by intra-uterine tokometry. By contrast, in the contracted pelvis there are no mouldings between the two parietal bones. In breech presentation during the first stage of labour the moulding of the skull bones is explained, by the differing resistance of the various skull bones against the amniotic fluid pressure.

Amniotic Fluid↗