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Biomedical subjects

G C Fisk

Publications and source records attributed to G C Fisk.

17 recordsLinked to original sources
PubMed1979

Thrombus formation on catheters in new born lambs.

Catheters were inserted into the aorta and inferior vena cava of newborn lambs by cutdown on the femoral vessels and directly into the umbilical vein. The lambs were killed after six days and the amounts of thrombus surrounding the cathethers were measured. Most catheters inserted into the umbilical vein looped within the liver and only a few passed directly into the portal vein or through the ductus venosus into the vena cava. On different types of catheters inserted via the femoral artery or femoral vein, there were significant differences both in the proportion with thrombus and the amount of thrombus. There were also significant differences in renal infarctions caused by different types of catheters.

Animals↗
PubMed1978

Gastric shake test and pharyngeal lecithin/sphingomyelin ratios in new born infants.

Gastric shake test and pharyngeal lecithin/sphingomyelin ratios were measured in newborn infants with respiratory difficulties, and in low birth weight infants in the immediate neonatal period. Both tests were useful in distinguishing infants with idioathic respiratory distress syndrome from those with respiratory difficulty due to other causes. However, in six infants with idiopathic respiratory distress syndrome, the pharyngeal lecithin/sphingomyelin ratio indicated mature lungs, and in three of these, the gastric shake test showed the presence of surfactant. Five of these six infants had been delivered by emergency lower segment caesarean section because of maternal complications, which might account for the discrepancy between the laboratory results and the clinical condition of the patient.

Cesarean Section↗
PubMed1977

Measurement errors in pneumotachography due to pressure transducer design.

When pneumotachography is used during intermittent positive pressure ventilation (IPPV), the design of some differential pressure transducers can cause measurement errors. These errors may be avoided by using differential pressure transducers which have small, equal chambers free from temperature sensitive electrical elements. Few of the transducers which are sensitive enough for clinical use fulfil these requirements.

Diagnostic Errors↗
PubMed1977

Technical considerations in the use of the membrane oxygenator (Lande'-Edwards) for open heart surgery.

Experience has shown that successful cardio-pulmonary bypass depends upon an efficient oxygenator which causes minimum blood damage. Experience with 1,600 Lande'-Edwards membrane oxygenators in more than 1,000 patients has led to the development of a simple and safe routine for their use in open heart surgery. The circuitry, method of preparation for perfusion, and management of perfusion are described in detail.

Adult↗
PubMed1976

The influence of duration of circulatory arrest at 20 degrees C on cerebral changes.

In infants and piglets subjected to periods of circulatory arrest at 20 degrees C there was close correlation between duration of arrest and delay in return of electroencephalographic activity. Post mortem studies demonstrated histological evidence of brain damage in patients after circulatory arrest at 20 degrees C. Similar histological changes were demonstrated in piglets, including some who had complete E.E.G. and clinical recovery from circulatory arrest.

Animals↗
PubMed1976

Measurement of thrombus formation on intravascular catheters.

Relative thrombogenicities of several brands of intravascular catheters were measured in the saphenous and cephalic veins of sheep. Differences in thrombogenicity between brands of up to eleven fold were found. At least one brand contained an ingredient which was locally toxic to sheep and which caused phlebitis in cannulated vessels. The brands tested were made from six types of plastics. It is suggested that differences in manufacturing technique may be more important than the type of plastic in determining the thrombogenicity of catheters.

Animals↗
PubMed1976

Aims and objectives for postgraduate learning in anaesthesia.

This paper describes the statement of aims and objectives of postgraduate training for the Faculty of Anaesthetists of the Royal Australasian College of Surgeons. The objectives of the authors are that after study of this paper, the readers will: (a) Understand the importance of both "stated" and "informal" objectives in teaching and learning. (b) Understand the important terms used in the Faculty of Anaesthetists' Document on objectives. (c) Know the strategies using in writing the Faculty's Document of Objectives.

Anesthesiology↗
PubMed1975

Evaluation of infant ventilators.

A method of evaluating the performance of paediatric ventilators under simulated clinical conditions is described, together with the results of this evaluation of the prototypes of two ventilators designed specifically for use with infants and small children.

Airway Resistance↗
PubMed1975

Mucosal changes in the trachea and main bronchi of newborn infants after naso-tracheal intubation.

Permanent sequelae of nasotracheal intubation are uncommon, but acute ulceration and squamous metaplasia occur. Histological sections from the trachea and main bronchi were examined in 12 infants. A nasotracheal tube had been inserted during the first two weeks of life of these infants and had been in place for more than one week. In four cases the patient died some time (7 to 108 days) after extubation. Similar sections from patients who were not intubated, intubated only for attempted resuscitation, or intubated for several hours were studied for comparison. The sections were classified according to the degree of mucosal loss and metaplasia, and the extent of the lesions was estimated. Squamous change was seen in most sections from all 12 patients with the exception of one who died 57 days after extubation. Some respiratory epithelium was seen in all patients. In the eight patients who died while intubated, the changes were more marked in the right main bronchus than the left in seven, and more marked in the lower trachea than the upper in five. In the two patients intubated for several hours, in addition to mucosal loss, early metaplasia was seen. It is suggested that mucosal loss is replaced by the squamous metaplasia, and that trauma caused by suction catheters in the lower trachea and right main bronchus is more extensive than that due to the endotracheal tube itself.

Bronchi↗
PubMed1975

The final F.F.A.R.A.C.S. examination.

The development of the Final Examination of Fellowship of the Faculty of Anaesthetists of the Royal Australasian College of Surgeons is described from its inception in 1956 to the present. A statistical analysis was made of the examinations in 1969 and 1970. The correlations between marks for essay questions, within the multiple choice examination and between clinical examinations were low, suggesting that the reliability of these tests was unsatisfactory. At this same time, applied anatomy was added to the subjects in this examination. The examination was restructured with more emphasis on the oral and multiple choice examination and the marking system was revised. Continuing analysis has shown higher correlations between and within most parts of the examination. The correlations for the essay marks have remained lower, but essays have been retained in an attempt to assess and encourage the skills involved. Feedback of teaching and learning information obtained from analysis of the examination is provided to Regional Education Officers and Supervisors of Training.

Anesthesiology↗
PubMed1975

Errors in pneumotachography with intermittent positive pressure ventilation.

Instrument errors that can occur when pneumotachography is used during Intermittedt Positive Pressure Ventilation (IPPV) have been described previously (Kafer 1973). Our efforts to eliminate these errors led to the discovery of further inaccuracies, which appear to be due to the design of the differential pressure transducers used with pneumotachograph head. A system was used in which a sine-wave pump delivered a constant tidal volume to a dummy lung, the tidal volume being measured by means of a pneumotachograph. Using Grass, Statham and Devices differential pressure transducers, the volume recorded as leaving the dummy lung was consistently greater than that recorded as entering, and changing the pneumatic polarity of the differential pressure transducer produced large differences in the recorded volume. In some cases the error was greater than the volume being measured. There would seem to be several causes of such errors. The Sanborn 270 differential pressure transducer and the Greer micromanometer appeared to be free of these artifacts. The results of this study throw into doubt much previously published work using pneumotachography during IPPV.

Equipment and Supplies↗
PubMed1975

Some advantages of the membrane oxygenator for open-heart surgery.

The Lande'-Edwards oxygenator has been used for clinical perfusions on 283 patients. Among these patients we have encountered the full range of congenital and acquired defects and a variance in age from 1 day to adulthood. Data are presented concerning the means and methods of perfusion, the defects involved, and the results of treatment. A comparison has been made between two groups of 20 adults each, one group perfused with a bubble oxygenator (Bently) and the other with the Lande'-Edwards membrane lung. This study showed that platelet function is better preserved by the membrane lung, that hemolysis is less severe, and that postoperative bleeding is reduced. Indirect evidence has been accumulated to suggest that pulmonary, cerebral, and renal function is also better preserved when the membrane lung is employed.

Adolescent↗