What is the algorithm for treating hypotension (low blood pressure)?

From the Guidelines

The treatment of hypotension should be based on the presumed underlying causes, including vasodilation, hypovolaemia, bradycardia, and low cardiac output, as recommended by the perioperative quality initiative (POQI) international consensus statement 1. When managing hypotension, it is crucial to identify and address the underlying cause while stabilizing the patient. The approach involves:

• Ensuring adequate fluid resuscitation with crystalloids like normal saline or lactated Ringer's solution, typically starting with a 500-1000 mL bolus in adults and reassessing.
• Using a passive leg raise (PLR) test to assess fluid responsiveness, as it strongly predicts fluid responsiveness with a positive likelihood ratio of 11 and a pooled specificity of 92% 1.
• If the PLR test is positive, administering intravenous fluid; otherwise, focusing on vascular tone and chronotropy/inotropy.
• Initiating vasopressors, such as norepinephrine, if hypotension persists despite fluid administration, as it increases both systemic vascular resistance and cardiac output with minimal tachycardia.
• Considering the use of other vasopressors, such as vasopressin, dobutamine, phenylephrine, or epinephrine, based on the patient's specific needs and underlying cause of hypotension. Throughout treatment, continuous monitoring of blood pressure, heart rate, urine output, and mental status is essential to maintain mean arterial pressure above 65 mmHg and ensure adequate organ perfusion. Key considerations in the management of hypotension include:
• The side-effect profile of drugs used in treatment, such as phenylephrine's potential to cause reflex bradycardia 1.
• The importance of addressing the underlying cause of hypotension, whether it be vasodilation, hypovolaemia, bradycardia, or low cardiac output, as recommended by the POQI international consensus statement 1.

From the FDA Drug Label

Restoration of Blood Pressure in Acute Hypotensive States Blood volume depletion should always be corrected as fully as possible before any vasopressor is administered. When, as an emergency measure, intraaortic pressures must be maintained to prevent cerebral or coronary artery ischemia, LEVOPHED can be administered before and concurrently with blood volume replacement After observing the response to an initial dose of 2 mL to 3 mL (from 8 mcg to 12 mcg of base) per minute, adjust the rate of flow to establish and maintain a low normal blood pressure (usually 80 mm Hg to 100 mm Hg systolic) sufficient to maintain the circulation to vital organs

The algorithm for treating hypotension involves:

• Correcting blood volume depletion as fully as possible before administering a vasopressor
• Administering norepinephrine (IV), such as LEVOPHED, at an initial dose of 2 mL to 3 mL (from 8 mcg to 12 mcg of base) per minute
• Adjusting the rate of flow to establish and maintain a low normal blood pressure (usually 80 mm Hg to 100 mm Hg systolic)
• Monitoring the patient's response and adjusting the dosage as needed, with an average maintenance dose ranging from 0.5 mL to 1 mL per minute (from 2 mcg to 4 mcg of base) 2

From the Research

Algorithm for Treating Hypotension

The treatment of hypotension is best targeted at the underlying etiology, although this can be difficult to discern early in a patient's disease course 3.

Key Aspects of Treatment

• Expedited bedside evaluation with rapid initiation of treatment based on the most likely underlying etiology is paramount, followed by serial reassessment of the patient's condition 3.
• Crystalloids are the preferred solution for the resuscitation of emergency department patients with severe sepsis and septic shock 4.
• Balanced crystalloids, such as lactated Ringer's, may improve patient-centered outcomes and should be considered as an alternative to normal saline, if available 4, 5.

Resuscitation Fluids

• Lactated Ringer's solution compared with 0.9% saline might be associated with improved survival in patients with sepsis-induced hypotension 6.
• Balanced crystalloid solutions have a sodium, potassium, and chloride content closer to that of extracellular fluid and, when given intravenously, have fewer adverse effects on acid-base balance 5.
• Normal saline may cause hyperchloremic metabolic acidosis, inflammation, hypotension, acute kidney injury, and death 5.

Comparison of Resuscitation Fluids

• A retrospective analysis of normal saline and lactated Ringer's as resuscitation fluid in sepsis did not show a statistically significant difference in mortality rates, hospital LOS, ICU admission after diagnosis, mechanical ventilation, oxygen therapy, and RRT between the two groups 7.
• However, the study suggested that further large-scale prospective studies are needed to solidify the current guidelines on the use of balanced crystalloids 7.