Effects of head-down positioning on regional central nervous system perfusion in isoflurane-anesthetized horses

Abstract

Head-down positioning increased heart-brain hydrostatic gradients in isoflurane-anesthetized horses, thereby decreasing cerebral blood flow and, to a greater extent, increasing ICP. During anesthesia, CNS regions with low blood flows in horses may be predisposed to ischemic injury induced by high ICP.

The effect of xylazine on intracranial pressure in anesthetized and standing horses

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg 15,17–21 . The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg.…”

“…15,21 The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions. 17,18,20,21 The baseline CPP reported here falls within this range at 50 ± 8 mm Hg. Factors that have been determined to affect CPP include duration of anesthesia 20 and type of recumbency.…”

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg. 15,[17][18][19][20][21] The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia.…”

“…The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia 15,21 . The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions 17,18,20,21 .…”

The effect of xylazine on intracranial pressure in anesthetized and standing horses

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg 15,17–21 . The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg.…”

“…15,21 The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions. 17,18,20,21 The baseline CPP reported here falls within this range at 50 ± 8 mm Hg. Factors that have been determined to affect CPP include duration of anesthesia 20 and type of recumbency.…”

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg. 15,[17][18][19][20][21] The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia.…”

“…The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia 15,21 . The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions 17,18,20,21 .…”

Successful cardiopulmonary resuscitation in an adult horse following cardiovascular collapse on recovery from general anaesthesia in the Trendelenburg position

“…In a study assessing central nervous system perfusion during Trendelenburg positioning, one horse developed an unexplained marked hypotension (Brosnan et al 2008). A further common feature between our case and the case reported by Brosnan et al (2008) is the infusion of dobutamine. Dobutamine has been reported in both dogs and humans to be capable of inducing a BJR reflex with associated periods of asystole (Hofmeister et al 2005;Parent and Lepage 2015).…”

The effect of xylazine on intracranial pressure in anesthetized and standing horses

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg 15,17–21 . The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg.…”

“…15,21 The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions. 17,18,20,21 The baseline CPP reported here falls within this range at 50 ± 8 mm Hg. Factors that have been determined to affect CPP include duration of anesthesia 20 and type of recumbency.…”

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg. 15,[17][18][19][20][21] The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia.…”

“…The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia 15,21 . The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions 17,18,20,21 .…”

Successful cardiopulmonary resuscitation in an adult horse following cardiovascular collapse on recovery from general anaesthesia in the Trendelenburg position

“…In a study assessing central nervous system perfusion during Trendelenburg positioning, one horse developed an unexplained marked hypotension (Brosnan et al 2008). A further common feature between our case and the case reported by Brosnan et al (2008) is the infusion of dobutamine. Dobutamine has been reported in both dogs and humans to be capable of inducing a BJR reflex with associated periods of asystole (Hofmeister et al 2005;Parent and Lepage 2015).…”

The effect of xylazine on intracranial pressure in anesthetized and standing horses

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg 15,17–21 . The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg.…”

“…15,21 The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions. 17,18,20,21 The baseline CPP reported here falls within this range at 50 ± 8 mm Hg. Factors that have been determined to affect CPP include duration of anesthesia 20 and type of recumbency.…”

“…The ICP of anesthetized horses in lateral recumbency has been documented in multiple studies with values ranging from 19.7 to 52 mm Hg. 15,[17][18][19][20][21] The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia.…”

“…The baseline ICP reported here falls within this range at 24.5 ± 3 mm Hg. Factors that have been determined to affect ICP in anesthetized horses include head down positioning, 18 type of recumbency, 17 duration of anesthesia, 20 and hypercapnia 15,21 . The CPP of anesthetized horses in lateral recumbency has also been previously reported ranging from 35 to 82 mm Hg depending on the study conditions 17,18,20,21 .…”

Successful cardiopulmonary resuscitation in an adult horse following cardiovascular collapse on recovery from general anaesthesia in the Trendelenburg position

“…In a study assessing central nervous system perfusion during Trendelenburg positioning, one horse developed an unexplained marked hypotension (Brosnan et al 2008). A further common feature between our case and the case reported by Brosnan et al (2008) is the infusion of dobutamine. Dobutamine has been reported in both dogs and humans to be capable of inducing a BJR reflex with associated periods of asystole (Hofmeister et al 2005;Parent and Lepage 2015).…”