1 – Circulatory arrest in mature monkeys
Studies of neurological effects and neuropathology
of circulatory arrest in mature monkeys were
undertaken by Miller and Myers to determine if the
adult brain might not be more tolerant than
previously thought to episodes of total ischemia [1,
2]. Or is it only the newborn infant's brain that will
sustain no more than "minor" brainstem damage
during a lapse in respiration?
Miller and Myers devised a procedure for blocking
circulation to the brain but preserving blood flow to
the heart and lungs. Their highly upbeat conclusion
was that if normal blood pressure was maintained
during recovery, only the brainstem, spinal cord, and
Purkinje cell layer of the cerebellum sustained
damage, and only minor neurological deficits resulted
from a lapse of blood flow to the brain lasting 14 to
24 minutes!
The 1970 paper described both immediate and long-
term neurologic effects of circulatory arrest:
First, during the experimental procedure the pupils
began dilating within seconds of vascular occlusion
and were fully dilated within 15 to 30 seconds; tonic
movements occurred during this same period, but
thereafter the animals became flaccid. Regular
respiratory efforts were initially intense but ceased in
forty-five seconds. Gasping commenced after a
minute and a half and continued for 5 to 7 minutes.
More than 75 percent of the animals died within the
first four days. Although circulation to the heart was
maintained, a progressive diminution in contractile
force was noted during the period of arrested blood-
flow to the brain.
For animals that survived the procedure, following
restoration of circulation the dilated pupils began to
constrict reaching a pinpoint size in those more
severely injured. Gasping commenced after about
fifteen minutes but ceased, leading to another period
of apnea. Corneal reflexes began to return during
the first hour and were always present after 5 hours;
muscle tone increased over the following few hours
but led to extensor hypertonus and opisthotonic
posturing. Figure xx is a picture of a monkey in
opisthotonus (or decerebrate posture) from the 1970
paper of Miller and Myers.
Studies of neurological effects and neuropathology
of circulatory arrest in mature monkeys were
undertaken by Miller and Myers to determine if the
adult brain might not be more tolerant than
previously thought to episodes of total ischemia [1,
2]. Or is it only the newborn infant's brain that will
sustain no more than "minor" brainstem damage
during a lapse in respiration?
Miller and Myers devised a procedure for blocking
circulation to the brain but preserving blood flow to
the heart and lungs. Their highly upbeat conclusion
was that if normal blood pressure was maintained
during recovery, only the brainstem, spinal cord, and
Purkinje cell layer of the cerebellum sustained
damage, and only minor neurological deficits resulted
from a lapse of blood flow to the brain lasting 14 to
24 minutes!
The 1970 paper described both immediate and long-
term neurologic effects of circulatory arrest:
First, during the experimental procedure the pupils
began dilating within seconds of vascular occlusion
and were fully dilated within 15 to 30 seconds; tonic
movements occurred during this same period, but
thereafter the animals became flaccid. Regular
respiratory efforts were initially intense but ceased in
forty-five seconds. Gasping commenced after a
minute and a half and continued for 5 to 7 minutes.
More than 75 percent of the animals died within the
first four days. Although circulation to the heart was
maintained, a progressive diminution in contractile
force was noted during the period of arrested blood-
flow to the brain.
For animals that survived the procedure, following
restoration of circulation the dilated pupils began to
constrict reaching a pinpoint size in those more
severely injured. Gasping commenced after about
fifteen minutes but ceased, leading to another period
of apnea. Corneal reflexes began to return during
the first hour and were always present after 5 hours;
muscle tone increased over the following few hours
but led to extensor hypertonus and opisthotonic
posturing. Figure xx is a picture of a monkey in
opisthotonus (or decerebrate posture) from the 1970
paper of Miller and Myers.
- Miller JR, Myers RE
(1970) Neurological
effects of systemic
circulatory arrest in the
monkey. - Miller JR, Myers RE
(1972) Neuropathology of
systemic circulatory arrest
in adult monkeys.
Opisthotonus, or
"decerebrate posture"
"decerebrate posture"