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Biomedical subjects

L W Hall

Publications and source records attributed to L W Hall.

At least 73 records · Page 4Linked to original sources
PubMed1979

Radiographic evidence of impaired pulmonary function in laterally recumbent anaesthetised horses.

Studies in conscious and anaesthetised ponies demonstrated that starvation, anaesthesia and changes in body position influence the radiographic appearance of the lungs in the lateral and dorsoventral views. Radiographic appearances could not be closely correlated with blood gas values, but they suggested that the volume of the lowermost lung of the laterally recumbent animal is greatly reduced.

Anesthesia↗
PubMed1979

Oxygenation of pulmonary vein blood in conscious and anaesthetised ponies.

Catheters were implanted through the left atrium into large veins drawing blood from regions of the diaphragmatic lobes in five ponies. Measurement of oxygen and carbon dioxide tensions in blood samples drawn through these catheters showed that in laterally recumbent conscious and anaesthetised animals the function of the lowermost lung is progressively impaired while in the supine position the function of both lungs is adversely affected.

Anesthesia↗
PubMed1978

The effects of a simulated refinery effluent on the grass shrimp, Palaemonetes pugio.

Duplicate static bioassays were conducted using a simulated refinery effluent on the grass shrimp (Palaemonetes pugio, Hippolyte sp.) with the LC-50 values recorded at 4-, 8-, 24-, 48-, and 96-hr intervals. The stimulated refinery effluent contained phenol (0.10 mg/L), sulfide (0.17 mg/L), chromium (0.25 mg/L), ammonia (10 mg/L), No. 2 fuel oil (10 mg/L), and kaolinite (20 mg/L). This arbitrary reference mixture (ARM) contains approximately the concentration of compounds recommended by EPA for 1977. Of the six ARM components, No. 2 fuel oil was the most toxic followed in decreasing order by sulfide, ammonia, phenol, chromium, and kaolinite. Temperature was the most important environmental variable affecting short term toxicity of the ARM to the grass shrimp. Light intensity, photo-period, and salinity had no significant effect. There was no difference in sensitivity of grass shrimp collected from five locations along the gulf and eastern coasts of the United States. Similarly, there was no difference in the response of two grass shrimp genera, Palaemonetes and Hippolyte to the ARM and there was no differences among the three species of Palaemonetes tested. In comparing the sensitivities of the two genera of grass shrimp and the pinfish (Lagodon rhombroides) to the ARM, the grass shrimp were more sensitive.

Animals↗
PubMed1978

Temperature preference of the crayfish Orconectes obscurus.

Acclimation temperature influenced the acute preferred temperature of the crayfish Orconectes obscurus. This species preferred a higher temperature than its acclimation temperature for those acclimation temperatures ranging from 6 degrees to 26 degrees C. When acclimated to 30 degrees and 33 degrees C, the crayfish preferred a lower temperature than its acclimation temperature. The final temperature preferendum is estimated to be approximately 30 degrees C.

Acclimatization↗
PubMed1977

Clinical evaluation of enflurane in the dog.

Enflurane (Ethrane; Abbott Laboratories Ltd), a new inhalation anaesthetic, was used on 30 clinical cases. A surgical plane of anaesthesia was quickly obtained and recovery was rapid. Respiratory depression occurred with a reduction in rate which was more marked in deeper planes of anaesthesia. Hypotension was not severe and was more marked in deeper plans of anaesthesia. Clinically the agent did not appear to be a good analgesic. No signs of spontaneous muscle activity were seen, possibly due to premedication with acepromazine.

Anesthesia, Inhalation↗
PubMed1975

Papers and articles measurement of central venous pressure in horses.

Central venous pressure measurements were made in 74 horses and ponies free from clinical evidence of cardiopulmonary disease. Using the sternal manubrium as the zero reference point, the mean value obtained was 12 cm H2O (S.D. +/- 6). There was a significant correlation with body weight (r=0.6, p less than 0.001) but there was none with age, sex, breed or type. During halothane anaesthesia, using the same reference point, the mean value was 24.5 cm H2O (S.D. +/- 6) in 28 animals in right lateral recumbency, 29 cm H2O (S.D. +/- 8) in 17 animals in left lateral recumbency and -6 cm H20 (S.D. +/- 4) IN 27 supine animals. The use of the sternal manubrium as zero reference point did not allow comparison of values in standing and recumbent animals and it was considered that serial measurements were of more value than isolated determinations in assessing the circulatory state of an animal.

Acepromazine↗
PubMed1975

Positive end-expiratory pressure in anaesthetized spontaneously breathing horses.

Horses breathing spontaneously under halothane anaesthesia were subjected to expiratory resistance by the introduction of a water-trap into the expiratory limb of a circle absorber. Resistances of 10 and 20 cm H2O produced no significant increase in PaO2 (P greater than 0.05) during halothane/air and halothane/oxygen anaesthesia. The imposition of resistance was associated with an increase in PaCO2 and a significant increase in mixed venous PCO2. In three animals subjected to 20 cm H2O resistance under halothane/air anaesthesia, the cardiac output was reduced (P less than 0.01). It was concluded that the indiscriminate application of end-expiratory pressure has no place in routine equine anaesthesia.

Airway Resistance↗
PubMed1975

The use of intravascular catheters for long-term studies on the mare and fetus.

Methods developed for the insertion of catheters into the umbilical artery and vein and the uterine vein of the pregnancy mare are described. The technique requires careful anaesthesia and the maintenance of normal blood gas tensions, pH and arterial blood pressure. Fetal survival was variable: three mares delivered live foals and six fetuses survived more than 15 days with a maximal period of 41 days. The erythrocytes sedimentation rate (ESR) of the fetal foal was always very low at operation but subsequently increased slightly; a sudden large rise in ESR usually indicated imminent fetal death. The relatively sudden death in utero of catheterized fetuses maintained for 10 days or more remains unexplained. Nevertheless, the stability and relatively long duration of some of these preparations are sufficient to investigate various aspects of placental exchange and the endocrine climate of the fetus.

Anesthesia↗