Avoiding Postinduction Hypotension: the Clinical ZERO-HYPOTENSION Proof-of-concept Study

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.

Inclusion criteria

• American Society of Anesthesiologists physical status classification III or higher, and in whom intraarterial blood pressure monitoring is planned for clinical indication

Exclusion criteria

• Emergency surgery
• Transplant surgery
• History of organ transplant
• Sepsis
• Pregnancy
• Contraindications for the use of propofol
• Rapid sequence induction