In this clinical proof-of-concept study, the aim is to investigate the efficacy of a hypotension avoidance strategy to prevent post-induction hypotension. Specifically, it will be investigate how much postinduction hypotension occurs when using a hypotension avoidance strategy - combining continuous intraarterial blood pressure monitoring, careful administration of anesthetic drugs, and continuous administration of norepinephrine to treat hypotension - in high-risk patients having elective non-cardiac surgery.
Hypotension is common in patients having non-cardiac surgery with general anesthesia and is associated with organ injury. About one third of hypotension occurs "postinduction" - i.e., after the induction of general anesthesia but before surgical incision. Unmodifiable risk factors for postinduction hypotension include age, male sex, and a high American Society of Anesthesiologists physical status. However, postinduction hypotension is mainly driven by modifiable factors - specifically, anesthetic drugs that cause vasodilation. Vasodilation can be effectively treated with vasopressors, e.g. norepinephrine. It is reasonable to assume that postinduction hypotension is largely avoidable by careful anesthetic and hemodynamic monitoring and management during anesthetic induction. A hypotension avoidance strategy could include continuous intraarterial blood pressure monitoring, careful administration of anesthetic drugs, and continuous administration of norepinephrine to treat hypotension. However, it remains unknown to which extent a hypotension avoidance strategy actually can avoid postinduction hypotension. Before testing the effectiveness of hypotension avoidance strategies in large-scale randomized trials it is important to investigate their efficacy. In this clinical proof-of-concept study, the aim is to investigate the efficacy of a hypotension avoidance strategy to prevent post-induction hypotension. Specifically, it will be investigate how much postinduction hypotension occurs when using a hypotension avoidance strategy - combining continuous intraarterial blood pressure monitoring, careful administration of anesthetic drugs, and continuous administration of norepinephrine to treat hypotension - in high-risk patients having elective non-cardiac surgery.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
120
Continuous blood pressure monitoring
Norepinephrine infusion will be prepared and connected to peripheral or central venous catheter (infusion will not be started)
Propofol infusion will be started only when clinical effects of opioid are noticeable: 1.5 mg/kg propofol in patients less than 55 years old and 1.0 mg/kg propofol in patients 55 years or older over 90 seconds
Lower mean arterial pressure alarm threshold will be set to 75 mmHg
Lower mean arterial pressure intervention threshold will be 75 mmHg: continuous norepinephrine infusion will be started when mean arterial blood decreases below 75 mmHg
University Medical Center Hamburg-Eppendorf
Hamburg, Germany
Area under a MAP of 65 mmHg
Area under a mean arterial pressure (MAP) of 65 mmHg within the first 15 minutes of anesthetic induction \[mmHg x min\].
Time frame: First 15 minutes of induction of general anesthesia
Area under threshold
Area under a MAP of 60, 50, and 40 mmHg \[mmHg x min\]
Time frame: First 15 minutes of induction of general anesthesia
Duration
Duration of MAP \<65, \<60, \<50, and \<40 mmHg \[min\]
Time frame: First 15 minutes of induction of general anesthesia
Any Hypotension
Absolute \[n\] and relative \[%\] number of patients with any MAP measurement \<65, \<60, \<50, and \<40 mmHg
Time frame: First 15 minutes of induction of general anesthesia
1-minute Hypotension
Absolute \[n\] and relative \[%\] number of patients with at least one 1-minute episode of a MAP \<65, \<60, \<50, and \<40 mmHg
Time frame: First 15 minutes of induction of general anesthesia
Area above the curve
Area above a MAP of 100, 110, 120, 140 mmHg \[mmHg x min\]
Time frame: First 15 minutes of induction of general anesthesia
Norepinephrine
Cumulative dose of norepinephrine indexed to body weight \[μg kg-1\]
Time frame: First 15 minutes of induction of general anesthesia
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