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Biomedical subjects

D R Geiser

Publications and source records attributed to D R Geiser.

8 recordsLinked to original sources

Use of end-tidal CO2 tension to predict arterial CO2 values in isoflurane-anesthetized equine neonates.

End-tidal carbon dioxide tension (PetCO2) and arterial carbon dioxide tension (PaCO2) were determined and compared in isoflurane-anesthetized spontaneously breathing equine neonates. End-tidal carbon dioxide and PaCO2 values increased with respect to time. Difference between values of PetCO2 and PaCO2 increased over time. End-tidal carbon dioxide tension was useful to predict changes in and was more closely correlated with PaCO2 early in the anesthetic period (T less than or equal to 60 minutes). The dead space volume to tidal volume (Vd/Vt) ratio increased with respect to time, indicating increase in physiologic dead space in isoflurane-anesthetized foals. The data indicate that the increased difference between widening of the PetCO2 and PaCO2 values over time may have been attributable to hypoventilation and decreased pulmonary capillary perfusion of alveoli.

Anesthesia, Inhalation

Chemical restraint and analgesia in the horse.

Chemical restraint in the standing horse is used for a variety of procedures in veterinary medicine. The choice of agent depends on the physical status, temperament, and size of the patient; the procedure to be performed; and safety for the patient, veterinarian, and owner. The combination of certain agents may provide more desirable restraint and analgesia than does the use of individual agents. The use of analgesics in the horse is not without side effects, some of which may be detrimental to the patient's condition. Analgesics should be chosen with these untoward effects in mind. Draft breeds possess differences that may provide a challenge to the practitioner. One such difference is their clinically apparent increased sensitivity to tranquilizers and sedative-hypnotics; consequently, reduced dose regimens for chemical restraint should be employed initially.

Analgesia

Work intolerance in a horse with thyroid carcinoma.

A thyroid carcinoma was diagnosed in a 14-year-old competitive trail horse with a 3-month history of work intolerance. Abnormal findings included low base-line triiodothyronine (T3) and thyroxine (T4) values, a large thyroid gland and decreased work tolerance. Nuclear medicine scanning revealed displacement of the right thyroid gland by a mass. Needle biopsy of the mass revealed neoplastic changes compatible with thyroid carcinoma. After removing the tumor surgically, T3 and T4 values returned to normal. Subsequently, the horse was able to compete successfully. Horses with work intolerance combined with a large thyroid gland may develop a thyroid carcinoma. In such horses, T3 and T4 values should be determined; if abnormal values are detected, needle biopsy and scintigraphic evaluation should be considered.

Animals

Management of thermal injuries in large animals.

The pathophysiology and histopathology of thermal burns in large animals is very similar to that in humans. Burns are classified as first degree, superficial and deep second degree, third degree, and fourth degree, depending upon the depth of thermal injury. Most severe burns will produce a local and a systemic response--both of which must be properly treated to increase the patient's chances for survival. The systemic response is mainly characterized by hypovolemia, fluid and electrolyte loss, protein loss, pulmonary edema, increased caloric requirements, and depressed immune responses. The local response is one of inflammation, vasospasm fluid accumulation, and electrolyte shifts depending upon the extent of the thermal injury. In all burn cases, the total patient should be evaluated. There is a tendency to focus on the wound, and systemic problems may be overlooked. In many cases, the thermal wound cannot be accurately evaluated for a few days, especially in large animals. An attempt should be made to estimate the depth of the burn, because treatment will vary accordingly. The treatment method must consider several problems. These include evaporative fluid and electrolyte loss, protection against mechanical injury, prevention of bacterial invasion and infection, maintenance of body temperature, and removal of nonviable tissue while leaving viable germinal tissue for healing. Thermal injuries in large animals present several additional problems. Many burns in large animals involve a large surface area, which increases the fluid, electrolyte, and caloric losses. Because most veterinary hospitals are not equipped to control the patient's surroundings, extensive bacterial contamination of the burn is of major concern. Patient restraint must also be a consideration to prevent further injury of the healing wound. Many patients are pruritic, and proper measures must be taken to prevent self-mutilation. There is also a lack of technically trained personnel to monitor and properly treat burn patients.

Animals