Why would a provider order a systolic blood pressure goal >90 over a mean arterial pressure (MAP) goal of >65 when titrating vasopressors?

Why Order SBP >90 Instead of MAP >65 When Titrating Vasopressors?

A provider would order a systolic blood pressure (SBP) goal >90 mmHg over a MAP goal >65 mmHg when both parameters serve different clinical purposes: MAP >65 mmHg is the primary target for initiating and maintaining vasopressor therapy to ensure adequate organ perfusion, while SBP >90 mmHg serves as a secondary threshold to identify persistent organ dysfunction and guide escalation of care. 1

Understanding the Dual Threshold System

The distinction between these two blood pressure targets reflects different stages and severity of shock management:

MAP ≥65 mmHg: The Primary Vasopressor Target

• MAP represents the driving pressure for tissue perfusion and is the standard initial target when starting vasopressors in septic shock and vasodilatory states 1, 2
• Norepinephrine should be titrated to maintain MAP at 65 mmHg after adequate fluid resuscitation in maternal sepsis and other shock states 1
• This target balances adequate organ perfusion while minimizing risks of arrhythmias and excessive vasopressor requirements 1
• Below the critical MAP threshold, tissue perfusion becomes linearly dependent on arterial pressure as autoregulatory mechanisms fail 1, 2

SBP <90 mmHg: A Marker of Persistent Organ Dysfunction

• SBP <90 mmHg defines persistent organ dysfunction in both severe sepsis and septic shock, serving as a clinical criterion beyond MAP 1
• Two sequential blood pressures with SBP <90 mmHg (or <85 mmHg if 20 weeks pregnant to 3 days postpartum) trigger escalation to the 6-hour sepsis bundle and consultation with critical care 1
• This threshold identifies patients who require more aggressive monitoring, potential invasive hemodynamic monitoring, and consideration of additional vasopressor agents 1

Clinical Algorithm for Blood Pressure Target Selection

Initial Resuscitation Phase

1. Start with MAP-guided therapy: Initiate vasopressors when MAP remains <65 mmHg after adequate fluid resuscitation 1
2. Titrate norepinephrine to achieve MAP ≥65 mmHg as the primary goal 1
3. Monitor SBP simultaneously as a secondary parameter to assess severity 1

When to Prioritize SBP Monitoring

A provider would specifically order an SBP goal >90 mmHg in these scenarios:

• Maternal sepsis patients: Where SBP <90 mmHg (or <85 mmHg in pregnancy/early postpartum) specifically triggers escalation protocols 1
• Screening for persistent organ dysfunction: When assessing whether a patient meets criteria for severe sepsis versus septic shock 1
• Trauma or hemorrhagic shock: Where permissive hypotension strategies target SBP 80-90 mmHg in patients without traumatic brain injury 1
• Elderly patients: Where lower MAP targets (60-65 mmHg) may be appropriate, but SBP monitoring helps avoid excessive hypotension 1, 3

Critical Pitfalls and Caveats

Common Misunderstandings

• Blood pressure alone does not reflect cardiac output or adequate tissue perfusion 2
• MAP and SBP serve complementary but distinct roles: MAP guides vasopressor titration, while SBP identifies severity thresholds 1, 2
• Achieving MAP ≥65 mmHg does not guarantee adequate perfusion if SBP remains <90 mmHg, suggesting more severe shock 1

Additional Monitoring Required

Beyond blood pressure targets, providers must assess:

• Lactate clearance (repeat within 6 hours if elevated) 1, 2
• Urine output as an indicator of renal perfusion 1, 2
• Mental status, skin perfusion, and capillary refill 2
• Volume status and tissue perfusion through clinical assessment or bedside echocardiography 1

Special Population Considerations

• Chronic hypertension: May require higher MAP targets (80-85 mmHg) to reduce need for renal replacement therapy 1
• Elderly patients >75 years: Lower MAP targets (60-65 mmHg) may reduce mortality compared to higher targets (75-80 mmHg) 1, 3
• Pregnant/postpartum patients: Use SBP <85 mmHg as the threshold (rather than <90 mmHg) from 20 weeks gestation through 3 days postpartum 1

Practical Implementation

When writing orders, specify both targets with clear escalation criteria:

• Primary goal: "Titrate norepinephrine to maintain MAP ≥65 mmHg"
• Secondary monitoring: "Notify MD if SBP <90 mmHg on two consecutive readings despite MAP ≥65 mmHg"
• This approach ensures the team recognizes when a patient requires escalation of care despite achieving the MAP target 1

The dual threshold system allows early identification of patients with more severe shock who may need additional vasopressors (vasopressin, epinephrine), invasive monitoring, or critical care consultation 1