Why does sepsis cause a wide pulse pressure?

From the Guidelines

Sepsis causes wide pulse pressure primarily due to the systemic inflammatory response that leads to vasodilation and decreased vascular resistance, as evidenced by the excessive nitric oxide production triggered by bacterial toxins and inflammatory mediators like cytokines 1.

Pathophysiology of Sepsis-Induced Wide Pulse Pressure

The pathophysiology of sepsis-induced wide pulse pressure can be attributed to several key factors:

• Vasodilation: The systemic inflammatory response in sepsis leads to the production of inflammatory mediators, which cause profound peripheral vasodilation, reducing systemic vascular resistance 1.
• Decreased vascular resistance: The decreased vascular resistance results in a significant drop in diastolic blood pressure, while systolic pressure may be maintained or less severely affected, leading to an increased difference between systolic and diastolic pressures 1.
• Increased cardiac output: Sepsis often causes tachycardia as the heart attempts to compensate for reduced vascular tone by increasing cardiac output, further contributing to the wide pulse pressure 1.
• Myocardial depression: As sepsis progresses to septic shock, myocardial depression may develop, potentially altering the hemodynamic picture 1.

Clinical Implications of Wide Pulse Pressure in Sepsis

The widened pulse pressure in sepsis is an important clinical sign that helps distinguish septic shock from other forms of shock, which typically present with narrowed pulse pressure due to decreased cardiac output.

• The use of dynamic measures, such as pulse pressure variation, can help predict fluid responsiveness in patients with sepsis or septic shock, with a sensitivity of 0.72 and a specificity of 0.91 1.
• Mean arterial pressure (MAP) is the driving pressure of tissue perfusion, and a target MAP of 65 mm Hg is recommended in patients with septic shock requiring vasopressors 1.

Management of Sepsis-Induced Wide Pulse Pressure

The management of sepsis-induced wide pulse pressure involves early effective fluid resuscitation, with an initial target of 30 mL/kg of crystalloid within the first 3 hours, and further fluid administration guided by functional hemodynamic measurements 1.

• The use of echocardiography and other non-invasive or invasive monitoring techniques can help assess cardiac function and guide fluid management 1.
• The goal of treatment is to normalize lactate levels and improve tissue perfusion, with a focus on early recognition and intervention to reduce morbidity and mortality 1.

From the Research

Sepsis and Pulse Pressure

• Sepsis is a life-threatening condition that can cause a wide range of symptoms, including changes in blood pressure and pulse pressure 2.
• Pulse pressure is the difference between systolic and diastolic blood pressure, and a widened pulse pressure has been identified as a potential prognostic indicator of mortality in patients with sepsis 2.

Mechanism of Wide Pulse Pressure in Sepsis

• The exact mechanism of wide pulse pressure in sepsis is not fully understood, but it is thought to be related to the body's response to infection and inflammation 2.
• Vasopressors, such as norepinephrine and vasopressin, are commonly used to treat septic shock and may affect pulse pressure 3, 4, 5, 6.
• However, the relationship between vasopressor use and pulse pressure is complex, and further research is needed to fully understand the mechanisms involved.

Clinical Implications

• A widened pulse pressure may be a valuable clinical tool in the early assessment of patients with sepsis and could be used as a prognostic factor to assess and implement management therapy 2.
• The use of vasopressors, such as norepinephrine and vasopressin, may be associated with changes in pulse pressure, and clinicians should be aware of this potential relationship when managing patients with sepsis 3, 4, 5, 6.