What is the treatment for postoperative hypotension?

From the Guidelines

Post-operative hypotension should be treated promptly with a systematic approach, prioritizing fluid resuscitation and vasopressor support as needed, with the goal of maintaining mean arterial pressure above 65 mmHg to ensure adequate organ perfusion, as recommended by the most recent consensus statement 1.

Treatment Approach

The treatment of post-operative hypotension involves a step-wise approach, starting with:

• Ensuring adequate fluid resuscitation with crystalloids (normal saline or lactated Ringer's) at 500-1000 mL boluses while monitoring response, as fluid responsiveness is a key factor in managing hypotension 1.
• If hypotension persists despite fluid administration, vasopressors may be necessary, with phenylephrine (50-200 mcg IV bolus or 0.1-0.5 mcg/kg/min infusion) useful for pure vasoconstriction, and norepinephrine (0.01-0.3 mcg/kg/min) preferred for patients with myocardial dysfunction 1.
• Simultaneously, identifying and treating underlying causes such as ongoing bleeding, vasodilation from anesthetics, or cardiac dysfunction, as these factors can contribute to hypotension 1.

Monitoring and Assessment

Continuous monitoring of vital signs, urine output, and mental status is crucial in managing post-operative hypotension, as it allows for prompt detection of any changes in the patient's condition 1.

• If hypotension is severe or unresponsive, consider echocardiography to assess cardiac function, as cardiac dysfunction can be a contributing factor to hypotension 1.

Goal of Treatment

The goal of treatment is to maintain mean arterial pressure above 65 mmHg to ensure adequate organ perfusion, as hypotension can lead to end-organ damage and increased morbidity and mortality 1.

Recent Consensus

The most recent consensus statement 1 emphasizes the importance of prompt treatment of post-operative hypotension, and recommends a systematic approach to management, including fluid resuscitation, vasopressor support, and identification and treatment of underlying causes.

From the FDA Drug Label

For blood pressure control in certain acute hypotensive states (e.g., pheochromocytomectomy, sympathectomy, poliomyelitis, spinal anesthesia, myocardial infarction, septicemia, blood transfusion, and drug reactions). As an adjunct in the treatment of cardiac arrest and profound hypotension. Phenylephrine Hydrochloride is an alpha-1 adrenergic receptor agonist indicated for increasing blood pressure in adults with clinically important hypotension resulting primarily from vasodilation, in such settings as septic shock or anesthesia. Dosing for Perioperative Hypotension • Intravenous bolus administration: 50 mcg to 250 mcg • Intravenous continuous infusion: 0.5 mcg/kg/minute to 1.4 mcg/kg/minute titrated to effect

Treatment of post-op hypotension may involve the use of vasopressors such as norepinephrine or phenylephrine.

• Norepinephrine can be used for blood pressure control in certain acute hypotensive states, including those resulting from anesthesia 2.
• Phenylephrine is indicated for increasing blood pressure in adults with clinically important hypotension resulting from vasodilation, including perioperative hypotension 3. The recommended dosing for phenylephrine in perioperative hypotension is an intravenous bolus administration of 50 mcg to 250 mcg or an intravenous continuous infusion of 0.5 mcg/kg/minute to 1.4 mcg/kg/minute titrated to effect 3.

From the Research

Treatment of Post-Operative Hypotension

• The treatment of post-operative hypotension is crucial to prevent adverse outcomes, including myocardial infarction, death, acute kidney injury, and major adverse cardiac or cerebrovascular events 4, 5.
• Fluid resuscitation is a common approach to manage post-operative hypotension, with the choice of fluid being a topic of debate 6, 7.
• Balanced crystalloids and normal saline are two commonly used fluids for resuscitation, with studies suggesting that balanced crystalloids may reduce the risk of death in patients with non-traumatic brain injury, but increase the risk of death in those with traumatic brain injury 6.
• However, other studies have found no significant difference in mortality, acute kidney injury, or renal replacement therapy between balanced crystalloids and normal saline 6, 7.
• The use of colloids, such as albumin, and fresh frozen plasma may also be beneficial in maintaining endothelial glycocalyx barrier function and mitigating endothelial injury and inflammation 8.

Fluid Resuscitation Strategies

• Low-volume resuscitation with normal saline may be associated with microvascular endothelial dysfunction after hemorrhage, compared to colloids and balanced crystalloids 8.
• Lactated Ringer's solution may have lesser effects on increased permeability and leukocyte rolling compared to normal saline 8.
• Albumin may stabilize permeability and white blood cell rolling/adhesion post-shock, comparable to fresh frozen plasma 8.

Blood Pressure Management

• Post-operative blood pressure management is challenging due to the numerous causes of blood pressure alterations after surgery 5.
• There is increasing evidence that hypotension during the initial days after non-cardiac surgery is associated with post-operative adverse outcomes 4, 5.
• However, robust evidence for a causal relationship between post-operative blood pressure and post-operative adverse outcomes is still lacking 5.