Permissive Hypotension Has No Deleterious Impact on Fluid Balance or Kidney Function

Area of Science:

• Critical Care Medicine
• Nephrology
• Sepsis Pathophysiology

Background:

• Sepsis management guidelines recommend targeting a mean arterial pressure (MAP) of 65 mm Hg or higher.
• The safety and consequences of allowing MAP between 55 and 65 mm Hg in septic patients without signs of hypoperfusion remain unclear.
• Understanding fluid balance and kidney function under permissive hypotension is crucial for optimizing sepsis care.

Purpose of the Study:

• To evaluate the safety and impact of permissive hypotension (MAP 55-65 mm Hg) on fluid balance and kidney function in septic patients.
• To compare outcomes between septic patients managed with permissive hypotension versus those requiring vasopressors for septic shock.

Main Methods:

• Retrospective analysis of consecutive septic patients admitted to a tertiary teaching hospital ICU over one year.
• Patients with MAP < 65 mm Hg despite fluid resuscitation were divided into two groups: permissive hypotension (MAP 55-65 mm Hg without peripheral hypoperfusion) and septic shock (MAP corrected with norepinephrine).
• Data collected included demographics, infection sources, Sequential Organ Failure Assessment (SOFA) scores, fluid administration, urinary output, and KDIGO scores for kidney injury.

Main Results:

• Ninety-four patients were included: 15 in the permissive hypotension group and 79 in the septic shock group.
• The septic shock group had higher SOFA scores (p < 0.0001) and mortality (38% vs. 0%, p < 0.01).
• Permissive hypotension patients received less fluid in the first 6 hours (p = 0.03), had higher urinary output (p < 0.001), and lower KDIGO scores at 48 hours (p < 0.05).

Conclusions:

• Mean arterial hypotension between 55 and 65 mm Hg can be safely tolerated in septic patients without clinical peripheral hypoperfusion.
• This strategy, termed permissive hypotension, did not necessitate vasopressor use and was associated with reduced fluid administration and less kidney damage.
• Permissive hypotension appears to be a safe and potentially beneficial approach in select septic patients, warranting further investigation.