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Biomedical subjects

T R Abbott

Publications and source records attributed to T R Abbott.

16 recordsLinked to original sources
PubMed1995

Effect of temperature and cardiopulmonary bypass on the auditory evoked response.

We have recorded auditory evoked potentials before and during cardiopulmonary bypass in 10 adult patients undergoing cardiac surgery under moderate hypothermia to 27-28 degrees C. The immediate effect of bypass was a small decrease in latency and increase in amplitude of the early cortical response. We also studied two adults and two children during profound hypothermia with circulatory arrest during cardiopulmonary bypass. Reduction in core temperature to 25 degrees C resulted in an increase in latency and amplitude of the brain stem responses; below this temperature the amplitude decreased but latency continued to increase until the auditory evoked response trace became completely flat between 21 and 19 degrees C. These changes were reversible on rewarming.

Aged↗
PubMed1984

Acid-base control during hypothermia. Acid-base control in children during hypothermia without temperature correction of pH and PCO2.

In 28 children undergoing cardiopulmonary bypass with deep hypothermia for open heart surgery, an attempt was made to maintain pH at 7.4 not corrected for temperature by varying the CO2 concentration supplied to the oxygenator so that the PaCO2 was 5.33 kPa, not corrected for temperature. One to two percent CO2 gave satisfactory results. Five percent CO2 had previously been given. No adverse clinical side effects were noted, and the acid-base status remained stable for 24 hours in 16 patients. There are strong theoretical reasons for maintaining a pH of 7.4, uncorrected for temperature, during hypothermia and a clinical impression was gained of better myocardial function and improved systemic and cerebral perfusion.

Acid-Base Equilibrium↗
PubMed1984

Hypothermic cardiopulmonary bypass in a patient with sickle-cell trait.

A male patient, aged 7.5 years, with known sickle cell trait, presented for correction of Fallot's tetralogy. The successful management under hypothermic cardiopulmonary bypass is described and the behaviour of sickle haemoglobin under hypothermic conditions is discussed.

Anemia, Sickle Cell↗
PubMed1984

Intra-operative awakening to monitor spinal cord function during scoliosis surgery. Description of the technique and report of four cases.

We used a modification of the wake-up test to monitor spinal cord function in 102 consecutive scoliotic patients undergoing Harrington instrumentation. Four patients were found to have a neural deficit when they were awakened during the operation. Three recovered immediately after partial release of the distracting force; one required immediate removal of the rod and was left with a slight neural deficit. Using our method, we have encountered no problem in performing the wake-up test, although attention is drawn to the difficulty in repeating the test if the patient is re-anaesthetised with diazepam. There were no false negative results in this series.

Adolescent↗
PubMed1983

Changes in serum calcium fractions and citrate concentrations during massive blood transfusions and cardiopulmonary bypass.

Total serum calcium, its fractions and serum citrate concentrations were measured in children receiving massive blood transfusion for scoliosis surgery, and in other children undergoing open heart surgery with cardiopulmonary bypass. During scoliosis surgery, although up to 100% of blood volume was replaced, and no additional calcium salts were infused, serum ionized calcium concentration remained within normal limits, provided that infusion rates of blood did not exceed 30 ml kg-1 h-1. During cardiopulmonary bypass, in which citrate-containing blood priming solutions were used, serum ionized calcium concentrations decreased markedly during perfusion associated with extremely high serum citrate concentrations. Serum ionized calcium concentrations returned to normal by the end of bypass, but serum citrate concentrations remained five times the normal concentration 5 h after bypass.

Adolescent↗
PubMed1980

Mass spectrometer measurement of oxygen uptake and carbon dioxide exchange during cardiopulmonary bypass.

Oxygen uptake (VO2) and carbon dioxide output (VCO2) were measured continuously in four children during cardiopulmonary bypass, using the variation in concentration of a tracer gas, argon, as a measure of flow, and a mass spectrometer to monitor gas concentrations. Normal values for the ratio of VCO2:VO2 (= 0.8) indicated that gas exchange equilibrium had been established following sudden changes in body temperature. During rapid cooling, 10% carbon dioxide is necessary to ensure carbon dioxide homeostasis within the body.

Body Temperature↗
PubMed1977

The use of sodium nitroprusside in children.

The hypotensive response to sodium nitroprusside was investigated in 30 children, age range 5-15 years, weight range 14-60 kg, who were undergoing spinal surgery for kyphoscoliosis. It was possible to achieve a constant level of satisfactory hypotension within the range 70-80 mmHg systolic arterial pressure using sodium nitroprusside infused at a rate of 10 microng/kg/minute and no serious side effects were experienced at this dose rate.

Adolescent↗
PubMed1977

Oxygen uptake following deep hypothermia.

Oxygen uptake of the body (Vo2) was measured in 9 children undergoing surgical correction of congenital heart lesions using cardiopulmonary bypass and deep hypothermia at 20 degrees tc with circulatory arrest. Initial levels of Vo2 following circulatory arrest were found to be four times greater than would have been expected from the normal relationship between Vo2 and body temperature, but within 8-10 minutes had fallen to normal levels. The quantity of oxygen taken up by the body during this time is similar to theoretical values for the quantity of oxygen inphysical solution, at 20 degrees C, in the tissues. It is postulated that during deep hypothermia the increased amount of oxygen in physical solution in the body plays an important part in preventing tissue damage during circulatory arrest.

Adolescent↗