Objective—To determine the cardiovascular and respiratory
effects of water immersion in horses recovering
from general anesthesia.
Animals—6 healthy adult horses.
Procedure—Horses were anesthetized 3 times with
halothane and recovered from anesthesia while positioned
in lateral or sternal recumbency in a padded
recovery stall or while immersed in a hydropool.
Cardiovascular and pulmonary functions were monitored
before and during anesthesia and during recovery
until horses were standing. Measurements and
calculated variables included carotid and pulmonary
arterial blood pressures (ABP and PAP, respectively),
cardiac output, heart and respiratory rates, arterial
and mixed venous blood gases, minute ventilation,
end expiratory transpulmonary pressure (PendXes),
maximal change in transpulmonary pressure
(ΔPtpmax), total pulmonary resistance (RL), dynamic
compliance (Cdyn), and work of breathing ().
Results—Immersion in water during recovery from
general anesthesia resulted in values of ABP, PAP, PendXes, ΔPtpmax, RL, and that were significantly greater and values of Cdyn that were significantly less,
compared with values obtained during recovery in a padded stall. Mode of recovery had no significant
effect on any other measured or calculated variable.
Conclusions and Clinical Relevance—Differences in
pulmonary and cardiovascular function between horses
during recovery from anesthesia while immersed
in water and in a padded recovery stall were attributed
to the increased effort needed to overcome the
extrathoracic hydrostatic effects of immersion. The
combined effect of increased extrathoracic pressure
and PAP may contribute to an increased incidence of
pulmonary edema in horses during anesthetic recovery
in a hydropool. (Am J Vet Res 2001;62:1903–1910)
Objective—–To compare transfixation and standard
full-limb casts for prevention of in vitro displacement
of a mid-diaphyseal third metacarpal osteotomy site
Sample Population—6 forelimbs from 6 horses
euthanatized for reasons not related to the musculoskeletal
Procedure—A 30° osteotomy was performed in the
mid-diaphysis of the third metacarpal bone. Two 4.5-mm cortical bone screws were placed across the
osteotomy site to maintain alignment during casting.
Two 6.35-mm Steinmann pins were placed from a lateral-to-medial direction in the distal aspect of the
radius. A full-limb cast that incorporated the pins was
applied. An extensometer was positioned in the
osteotomy site through a window placed in the dorsal
aspect of the cast, and after removal of the screws,
displacement was recorded while the limb was axially
loaded to 5,340 N (1,200 lb). Pins were removed,
and the standard full-limb cast was tested in a similar
Results—The transfixation cast significantly reduced
displacement across the osteotomy site at 445 N (100
lb), 1,112 N (250 lb), 2,224 N (500 lb), and 4,448 N
(1,000 lb), compared with the standard cast.
Conclusion and Clinical Relevance—A full-limb
transfixation cast provides significantly greater resistance
than a standard full-limb cast against axial collapse
of a mid-diaphyseal third metacarpal osteotomy
site when the bone is placed under axial compression.
Placement of full-limb transfixation casts should
be considered for the management of unstable fractures
of the third metacarpal bone in horses. (Am J
Vet Res 2000;61:1633–1635)