Effect of phenylephrine infusion on hypotension induced by the beach chair position

Abstract

Background: The beach chair position (BCP), used during shoulder surgery, is associated with hypotension, bradycardia, and risk of cerebral hypoperfusion. Phenylephrine is commonly used as a first treatment of choice of intraoperative hypotension during surgery. We evaluated the hemodynamic effects of 2 doses of intravenous phenylephrine infusion administered before being placed in BCP for arthroscopic shoulder surgery. The primary endpoint was the incidence of hypotension after positional change. Methods: Sixty-six patients were randomized to receive either intravenous normal saline (group NS) or intravenous phenylephrine infusion (0.5 μg/kg/min, group LP or 1.0 μg/kg/min, group HP) for 5 minutes before being placed in the BCP. Mean arterial pressure(MAP), heart rate, stroke volume variation, and cardiac index were measured before and after positional change. Results: The total incidence of hypotension after the BCP was 93.65%, but was not significantly different among the 3 groups. However, there was a significant difference in trends between the groups for MAP for 5 minutes after BCP ( P = .028). Comparison of changes in MAP at 1 minute compared to post-induction MAP was significantly different between group HP and group NS ( P = .014). Conclusion: Infusion of 0.5 and 1.0 μg/kg/min of phenylephrine for 5 minutes before the BCP has no preventive effect for incidence of hypotension. However, this study showed that 1.0 μg/kg/min of phenylephrine infusion for 5 minutes can attenuate the severity of hypotension.

Systemic and cerebral hemodynamic changes in patients undergoing shoulder arthroscopy in the beach chair position

“…After positioning we revealed further decreasing of SBP, DBP and MAP. Our data are similar to those obtained by M. Ko et al [14]. The total incidence of hypotension after placement into the BCP in their investigation came up 93.65 % in all patients.…”

Noninvasive Cardiac Output Monitoring (NICOM) in the Critically Ill Patient Undergoing Endotracheal Intubation: A Prospective Observational Study

“…However, one of the most common push dose pressors to treat hypotension in the critically ill, whether related to intubation or not (57.3% of patients utilized push dose pressors for ETI vs 38.2% of patients utilizing push dose pressors for transient hypotension according to 1 report 18 ), is phenylephrine. 19–21 Unlike norepinephrine which stimulates α 1 /α 2 receptors in addition to slight activity at β 1 /β 2 receptors, phenylephrine is a pure α 1 receptor agonist causing constriction of larger arterioles rather than terminal arterioles. 22 A prior randomized controlled trial concluded that there was no difference in outcomes when phenylephrine, instead of norepinephrine, was used as the first-line vasopressor for patients in septic shock.…”