58804
document
Effect of phenylephrine on the haemodynamic state and cerebral oxygen saturation during anaesthesia in the upright position . BACKGROUND The upright sitting or beachchair position is associated with hypotension , risk of cerebral hypoperfusion , and cerebral injury . We hypothesized that by increasing arterial pressure with phenylephrine administration , cerebral perfusion , and postoperative recovery would be improved . METHODS Thirty-four patients undergoing elective shoulder surgery were randomized to receive either saline or phenylephrine infusion ( PE ) 5 min before being placed in the upright position . Simultaneous measurements of mean arterial pressure , cerebral oxygen saturation , middle cerebral artery velocity , and cardiac function using transthoracic echocardiography were made . Postoperative neurocognitive function was assessed . RESULTS At the commencement of PE , mean ( SD ) cerebral oxygen saturation significantly decreased from 77 ( 10 ) to 67 ( 13 ) % ( P=0.02 ) , and further to 59 ( 11 ) % on upright positioning . The level of cerebral saturation upright was not significantly different to patients receiving saline ( P=0.07 ) , with values remaining at room-air levels . Middle cerebral artery blood velocity increased by 20 % ( P=0.04 ) . Phenylephrine prevented hypotension in the upright position primarily by maintaining preload and increasing systemic vascular resistance ( P=0.01 ) , and was associated with a decrease in cardiac output . No postoperative neurocognitive dysfunction was identified . CONCLUSIONS Despite maintaining arterial pressure with phenylephrine , cerebral desaturation occurred with upright positioning . Cerebral oxygen saturation can provide a valuable endpoint when evaluating the effect of vasopressor therapy on cerebral perfusion .
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Intervention_Pharmacological
phenylephrine
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Intervention_Pharmacological
phenylephrine
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Intervention_Pharmacological
saline or phenylephrine infusion ( PE )
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Intervention_Pharmacological
phenylephrine
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Outcome_Physical
haemodynamic state and cerebral oxygen saturation
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Outcome_Physical
hypotension , risk of cerebral hypoperfusion , and cerebral injury .
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Outcome_Physical
cerebral perfusion
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Outcome_Physical
postoperative recovery
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Outcome_Physical
mean arterial pressure , cerebral oxygen saturation , middle cerebral artery velocity , and cardiac function using transthoracic echocardiography
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Outcome_Mental
neurocognitive function
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Outcome_Physical
mean ( SD ) cerebral oxygen saturation
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Outcome_Physical
level of cerebral saturation upright
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Outcome_Physical
Middle cerebral artery blood velocity
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Outcome_Physical
hypotension
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Outcome_Physical
systemic vascular resistance
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Outcome_Physical
cardiac output .
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Outcome_Mental
postoperative neurocognitive dysfunction
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Outcome_Physical
cerebral desaturation
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Outcome_Physical
Cerebral oxygen saturation
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Participant_Sample-size
Thirty-four
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Participant_Condition
elective shoulder surgery