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Biomedical subjects

L E Larsson

Publications and source records attributed to L E Larsson.

At least 55 records · Page 3Linked to original sources
PubMed1987

Effects of rectal thiopentone and methohexitone on carbon dioxide tension in infant anaesthesia with spontaneous ventilation.

The influence of rectal administration of barbiturates on PCO2 during mask anaesthesia with spontaneous ventilation was studied in 72 infants. The age of the patients ranged between 6 and 24 months and they were all subjected to minor paediatric surgery. The patients were divided into four equally large groups: a control group receiving no premedication, a group receiving rectal thiopentone 30 mg X kg-1 and two groups receiving methohexitone either 20 or 30 mg X kg-1. In all patients PCO2 was measured in an arterialized capillary blood sample obtained during stable anaesthesia with oxygen, nitrous oxide and halothane before and after surgery. After rectal induction with barbiturates, the mean PCO2 was significantly higher in the different barbiturate groups than in the control group (P less than 0.05). The mean PCO2 value +/- s.d. in kPa for the control group was 5.6 +/- 0.7, for the group receiving thiopentone 30 mg X kg-1 6.5 +/- 1.6, for the groups receiving methohexitone 20 or 30 mg X kg-1 6.1 +/- 1.2 and 6.3 +/- 1.1, respectively. It is concluded that the combination of rectal induction with barbiturates and mask anaesthesia with oxygen, nitrous oxide and halothane carries an increased risk of hypoventilation in infants under 2 years of age.

Administration, Rectal↗
PubMed1987

Carbon dioxide tensions in infants during mask anaesthesia with spontaneous ventilation.

Carbon dioxide tensions (PCO2) in arterialized capillary blood samples were measured in 39 infants anaesthetized for minor paediatric surgery. Anaesthesia was induced and maintained with oxygen, nitrous oxide and halothane, using a Mapleson-D system with spontaneous ventilation and a Rendell-Baker face mask. The duration of anaesthesia was between 15 and 95 min. Two capillary blood samples were obtained during stable anaesthesia before and after surgery. The PCO2 values varied between 3.7 and 8.0 kPa. The highest values were found in infants aged 15-30 days, 6.6 +/- 0.7 kPa (mean +/- s.d.), compared to 5.9 +/- 0.7 in infants aged 31-60 days, 5.6 +/- 0.8 in infants aged 61-180 days and 5.5 +/- 0.7 in infants aged 181-300 days. Comparison between measurements before and after surgery did not in any group indicate a progressive hypoventilation or a correlation between the length of the anaesthesia and the PCO2. It is concluded that anaesthesia with oxygen, nitrous oxide and halothane with spontaneous mask ventilation is a satisfactory method for minor procedures in infants over 1 month of age, while in younger infants controlled ventilation with intubation may be a safer choice of method.

Anesthesia, Inhalation↗
PubMed1987

Prediction of symptomatic patent ductus arteriosus in preterm infants using Doppler and M-mode echocardiography.

To investigate whether the development of symptomatic patent ductus arteriosus could be predicted, 26 preterm infants dependent on mechanical ventilation were examined daily with Doppler and M-mode echocardiography until 3 days after birth. The presence or absence of a hemodynamically significant ductus shunt, as judged from echocardiographic criteria, was tested for predictive power in terms of sensitivity, specificity and total error rate. Out of the 26 infants 13 developed symptomatic patent ductus arteriosus at a median age of 5 days (range 2-8). These 13 infants developed echocardiographic evidence of a large shunt at a median age of 2 days (range 1-3). The sensitivity of prediction was 18, 46 and 100% at 1, 2 and 3 days after birth. The specificity was 80, 92 and 85% and the total error rate was 52, 32 and 8%. Thus, accurate prediction was possible 3 days after birth.

Ductus Arteriosus, Patent↗
PubMed1986

Incidence of heart disease and functional significance of changes in the electrocardiogram 10 years after radiotherapy for breast cancer.

Late cardiac complications after radiotherapy for breast cancer was studied in 197 patients examined before, 6 months after, and 10 years after treatment. The 10-year follow-up was done by survey of the files of patients who had died and re-examination of patients who were alive and free of cancer. Among 95 patients who died, 3 died of cardiopulmonary diseases. Autopsy in 32 patients showed serious cardiac abnormalities in 3. Of 102 patients alive at follow-up, 3 reported heart symptoms. Sixty-nine patients participated in the re-examination. Electrocardiogram (ECG) abnormalities were found in 19% of these patients before treatment; in 45% at 6 months, essentially due to T-wave changes in patients who had received left-sided irradiation; and in 45% at 10 years, with fewer T-wave abnormalities but more ST depression and ectopic beats. Average working capacity was 83 W before, 81 W at 6 months, and 84 W at ten years. Average heart volume was 680 ml before, 689 ml at 6 months, and 718 ml (P less than 0.01) 10 years after treatment. In conclusion, there was a high incidence of ECG T-wave changes, but they were reversible, and the perimyocardial damage indicated was functionally insignificant. The incidence of serious cardiac complications was low.

Autopsy↗
PubMed1986

Changes in gait patterns after operations in children with spastic cerebral palsy.

We have utilised a scoring system with the aid of a specially designed worksheet to measure gait ability in spastic children with cerebral palsy before and after corrective soft tissue operations. Postoperatively, there were obvious improvements in gait especially in the mobility of the leg and the foot. Comparison between a visually assessed score and objectively recorded values using foot-switches showed a good correlation. The postoperative improvement was most obvious in hemiplegic children, but was also present in diplegic children following both single and complex one-stage operations.

Adolescent↗
PubMed1986

Circulatory effects of carbon dioxide in experimental endotoxic shock.

In seven anaesthetized dogs the central circulatory effects of changes in Paco2 were studied before and after an intravenous injection of E. coli endotoxin 1.0 mg kg-1. The animals were on controlled ventilation with constant minute volumes, and Paco2 was changed by variations in the inspired gas mixture. Before endotoxin was given, cardiac output, mean aortic pressure, mean pulmonary artery pressure, total peripheral resistance and stroke volume were little affected by the changes in Paco2 from 3.9 +/- 0.4 to 7.2 +/- 0.4 kPa (mean +/- s.e.mean). Only heart rate decreased significantly (P less than 0.05). The intravenous endotoxin injection resulted in a decreased cardiac output (P less than 0.01), a decreased mean aortic pressure (P less than 0.01) and a decreased stroke volume (P less than 0.05). Mean pulmonary artery pressure, total peripheral resistance and heart rate showed only minor changes. In endotoxic shock an increase in Paco2 from 4.4 +/- 0.4 to 7.8 +/- 0.3 kPa (mean +/- s.e.mean) resulted in a significant increase in cardiac output (P less than 0.05), stroke volume (P less than 0.05) and mean pulmonary artery pressure (P less than 0.05), while the other parameters remained unchanged. It can be concluded that the carbon dioxide tension is of importance for the cardiac performance in experimental endotoxic stock in a manner not seen in control animals. The mechanisms behind these findings need further investigation.

Animals↗
PubMed1985

Cerebral effects of HDC.

HDC is commonly used in conditions with a raised intracranial pressure. An effect on cerebral edema was first described in patients with brain tumors, where the intracranial pressure can be lowered following administration of HDC. However, the use of HDC in cerebral edema of other origin is not equally well supported. Apart from effects on brain circulation secondary to the effects of HDC on brain edema, direct effects of HDC on cerebral blood flow and oxygen uptake have been studied mainly in experimental endotoxic shock. Endotoxin given intravenously leads to reduction in the cerebral blood flow and increase in the oxygen uptake. The increased oxygen uptake could be due to circulating catecholamines or other substances affecting the cerebral metabolism following their passage of a damaged blood-brain barrier. Pretreatment with HDC prevents the effects of endotoxin on cerebral blood flow and oxygen uptake. When HDC was given after an intravenous endotoxin injection blood flow was unaffected but the increased cerebral oxygen uptake was reduced transiently. This might hypothetically be explained by either a direct effect on the permeability of the blood-brain barrier or indirectly via a decrease of metabolically active circulatory substances.

Adrenal Cortex Hormones↗
PubMed1985

Skeletal muscle function in man: force, relaxation rate, endurance and contraction time-dependence on sex and age.

Two different methods for estimating muscle function were compared; hand grip strength (HGS) and adductor pollicis muscle function after electrical stimulation of the ulnar nerve. Fifty-two 'normal' subjects, who were divided into four groups, according to sex and age, were investigated. Technical modifications of the latter method are presented for the measurement of human skeletal muscle function, independent of the motivation of the subject. Maximal voluntary force, as measured with a hand dynamometer, was higher in males than in females. Young males were stronger than males over 50 years old, and young females were stronger than old women. The statistical analysis of the muscle function variables after electrical stimulation showed that young females developed relatively more force at low stimulating frequencies than females over 50 years old. Females had a significantly longer contraction time to tetany compared to males. The relaxation rate after tetanic stimulation was independent of sex and age. Endurance was reduced in old males compared to females in the same age-group and to young males.

Adult↗
PubMed1985

Simulation of paretic gait in normal subjects by loading the ankles.

Normal subjects were loaded with increasing weights (2-6 kg) applied around the ankles. During these conditions stride length increased in relation to velocity. The percentage duration of single support in relation to stride duration increased. Provided the same load was applied around both ankles increase was symmetrical. Consequently there was also an increase of swing as well as a decrease of stance and of double support. The results contrast in all respects to what was found in previous experiments when the load was carried in the hand. During these conditions stride length decreased as well as the duration of single support. The two experimental conditions differed in that with ankle loading the swing phase was loaded while in the other case stance was loaded. The two types of experiment may help to explain why some patients with paretic legs walk with short strides, while others walk with strides that are normal or slightly prolonged.

Adolescent↗
PubMed1984

Blood-glucose concentrations during anaesthesia in children. Effects of starvation and perioperative fluid therapy.

Blood glucose concentration, pH and standard bicarbonate concentration were measured in 70 anaesthetized children aged between 2 weeks and 22 months before and following surgery. The duration of starvation varied between 4 and 14 h (mean 5.8 h). The lowest blood-glucose concentration before operation was 2.9 mmol litre-1 (53 mg dl-1). Preoperative blood-glucose concentrations were not influenced by the age or weight of the child, or the duration of starvation. During operation the children received either a balanced Ringer acetate solution (group A) or a Ringer glucose solution containing 2.5% glucose (group B). In these patients the preoperative starvation did not result in hypoglycaemia and, during surgery, increases in blood-glucose concentration were found even in those children receiving a glucose-free fluid regimen.

Anesthesia, General↗
PubMed1984

Severe acute encephalitis--improved outcome after barbiturate treatment?

Six cases of severe encephalitis due to measles, varicellae, mononucleosis, influenza, rubella and pertussis were treated with high doses of barbiturates in combination with steroids and artificial hyperventilation. Four of the patients also received antiviral therapy. They all survived without neurological sequelae. The use of barbiturates in high doses may be of importance for an improved outcome in patients with severe encephalitis.

Acyclovir↗
PubMed1984

A comparison of the gaits of paretic patients with the gaits of control subjects carrying a load.

The gaits of 15 patients with peripheral and central paresis were studied. They were compared both with a control group of the same age and sex and with a group of nine subjects who carried varying weights. Velocity was low in the patients and this was due to decreases of both stride length and stride frequency. Load did not significantly decrease the velocity of the control subjects, since unlike the patients, they had the ability to compensate for a low stride length by significantly increasing stride frequency. The significant lowering of stride length in both groups was a similarity between them. The patients were also similar to the loaded normal subjects in having a shortened duration of the single support and a prolonged double support. The patients with hemisymptoms also showed significant differences between the two sides for the durations of both single and double support. The results obtained from this study justify our hypothesis that a subject who is carrying a load may in certain respects be considered as a model of a subject with paresis. The remaining differences may be explained by the fact that in the experimental situation, the leg was loaded only during stance, while in paresis the legs may be considered relatively loaded during the whole stride.

Adult↗
PubMed1983

Superior sagittal sinus blood flow in the dog measured by an electromagnetic flow meter. A comparison with a radioactive gas elimination method.

A simple method for continuous measurement of superior sagittal sinus blood flow (SSBF) in dogs, using an electromagnetic flow meter around the intact vessel, is presented. This method is compared with a procedure measuring radioactive gas elimination upon intra-arterial indicator injection. A good correlation between the cerebral blood flow (CBF), calculated from the fast component of the elimination curve and SSBF (r = 0.96) was found within a CBF range of 50-200 ml/100 g min.

Animals↗
PubMed1983

Early onset group B streptococcal disease. Seven year experience and clinical scoring system.

Early onset group B streptococcal disease was reviewed for the seven year period between 1975 to 1981 at Vanderbilt University Medical Center. One hundred and twenty cases were identified. The disease varied from asymptomatic bacteremia to fatal cardiopulmonary collapse. Factors associated with a poor outcome were prematurity, low Apgar score at 5 min, the presence of shock, leukopenia, rupture of membranes for more than 12 hours, and a delay in treatment after the onset of symptoms. A scoring system for probability of death based on these 6 factors was then developed. Over the seven year period mortality decreased from 50% to 10%. The only factor identified with the decrease in mortality was a significant decrease in the number of hours between the onset of symptoms and the beginning of treatment. Early recognition and prompt treatment seem to be the major causes of the decreasing mortality over the seven years of this report.

Apgar Score↗
PubMed1983

Effects of cyclooxygenase inhibition on the response to group B streptococcal toxin in sheep.

The effects of cyclooxygenase inhibition on the reaction to a toxin isolated from group B beta-hemolytic streptococci, type III, were studied in seven sheep instrumented for chronic measurement of pulmonary lymph flow, pulmonary artery and left atrial pressures. Each sheep was infused with toxin alone on one day and with indomethacin plus toxin on a different day in random order. The toxin alone caused a two-phased reaction. After the infusion of toxin, alone, in the initial phase, pulmonary artery pressure increased from 16.5 +/- 1.2 mmHg to 47.1 +/- 4.8 mmHg and the rectal temperature rose from 39.7 +/- 0.13 degree C to 40.9 +/- 0.16 degree C. During the second phase, the granulocyte count decreased to less than 10% of baseline values and the lymph protein clearance increased from 4.8 +/- 1.2 ml/h to 10.02 +/- 1.4 ml/h, suggesting increased pulmonary vascular permeability. Indomethacin pretreatment prevented the initial phase of pulmonary hypertension, the increases in thromboxane and prostacyclin metabolites in lung lymph, and the febrile response to toxin infusion but did not modify the granulocytopenia or the increased pulmonary vascular permeability. It appears that the hemodynamic changes are independent from the pulmonary vascular changes, and that prostaglandin endoperoxides or their metabolites are necessary for the fever and the acute pulmonary hypertension.

Animals↗
PubMed1983

Pulmonary hemodynamic and ultrastructural changes associated with Group B streptococcal toxemia in adult sheep and newborn lambs.

A toxin isolated from Group B beta-hemolytic streptococci, Type III was infused into adult sheep and newborn lambs. A two-phased reaction was observed. There was an initial phase of pulmonary hypertension and high flow of protein-poor lymph. This was followed by a second phase when pressures returned to baseline but lymph flow remained twice the baseline values and protein concentration in lymph increased. During the second phase there was a significant increase in lymph protein clearance, suggestive of increased microvascular permeability to protein. The absolute granulocyte count decreased to 10% of baseline values by 60 min after the infusion, and was followed by a variable return to baseline. The sheep with the largest changes in protein clearance were those who had the slowest return to baseline values. Pathologic examination of lung tissue revealed there was capillary dilation, interstitial edema, and large numbers of granulocytes in the lungs. The basement membranes of both capillaries and arterioles showed disruption and widening, along with fragmentation of the internal elastic membrane. This study provides morphologic and physiologic evidence of increased pulmonary vascular permeability after injection of streptococcal toxin associated with granulocyte trapping in the lung. We postulate that granulocytes may be involved as mediators of the pulmonary vascular injury.

Animals↗